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Oppen D, Schmidt F, Braitmaier SH, Hinrichs J, Weiss J. Modelling of dynamic mastication physics of cheese/casein gels as function of milk-fat distribution and intensity of thermo-mechanical treatment. Food Res Int 2024; 192:114694. [PMID: 39147542 DOI: 10.1016/j.foodres.2024.114694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 06/19/2024] [Accepted: 06/26/2024] [Indexed: 08/17/2024]
Abstract
Pasta filata-style cheese products are among the world's most famous cheese varieties. Thermo-mechanical processing of cheese curd results in stringy, fibrous, and anisotropic structures with pleasing texture attributes. A recent area of research focuses on improving yield during the manufacturing of pasta filata-type cheese products by homogenizing the milk. This process reduces the size of fat droplets, leading to better retention of milk fat during curd plasticization. As this sometimes results in texture deficits, this study aims to investigate the impact of thermo-mechanical processing on curd from homogenized and non-homogenized milk. The hypothesis is that increased thermo-mechanical processing, leading to more anisotropic structural elements, may offset texture deficits caused by homogenization. To assess textural and structural changes due to homogenization and thermo-mechanical processing, mechanical tests including rheology and texture analysis were conducted, along with confocal-laser-scanning microscopy. Additionally, sensory evaluation involving panelists consuming the samples and recording mastication properties such as muscle activity and jaw movement was carried out. Dynamic data modeling was used to derive connections between structure and texture. Results showed that homogenization alone did not yield significant differences between the samples, but plasticization and texturization properties differed significantly. Non-homogenized samples developed a distinct fibrous structure, and muscle activities and jaw movements increased significantly (p < 0.01) with longer thermo-mechanical processing.
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Affiliation(s)
- Dominic Oppen
- Department of Food Material Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstraße 25, 70599 Stuttgart, Germany
| | - Florian Schmidt
- Department of Soft Matter Science and Dairy Technology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstraße 21, 70599 Stuttgart, Germany
| | - Sarah Helena Braitmaier
- Department of Soft Matter Science and Dairy Technology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstraße 21, 70599 Stuttgart, Germany
| | - Jörg Hinrichs
- Department of Soft Matter Science and Dairy Technology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstraße 21, 70599 Stuttgart, Germany
| | - Jochen Weiss
- Department of Food Material Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstraße 25, 70599 Stuttgart, Germany.
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Alnajjar FA, Alloughani AJ, Alhajj MN, Baig MR. Fracture Resistance of Posterior Milled Nanoceramic Crowns after Thermomechanical Aging. J Funct Biomater 2024; 15:171. [PMID: 39057293 PMCID: PMC11278284 DOI: 10.3390/jfb15070171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 06/01/2024] [Accepted: 06/19/2024] [Indexed: 07/28/2024] Open
Abstract
Fracture resistance is an important parameter used to predict the performance of indirect dental restorations. The purpose of this in vitro study was to assess the fracture load of posterior milled nanoceramic crowns, in comparison with the lithium disilicate crowns, after fatigue loading, for two different restoration occlusal thicknesses. Forty test metal dies were fabricated by duplicating a master metal model consisting of an anatomic abutment preparation of the maxillary first premolar for a single crown. The dies were divided into two groups of 20 each for the fabrication of nanoceramic (Lava Ultimate) and lithium disilicate (IPS e.max CAD) single crowns. Each material group was further divided into two sub-groups of 10 dies each, based on crown occlusal thickness, of 0.5-mm and 0.75-mm (n = 10). Dental Type V stone dies poured from polyvinyl siloxane impressions of the test metal dies were laboratory scanned in order to design and mill 40 ceramic crowns. The crowns were cemented on to the test metal dies with a self-adhesive resin luting cement. All crowns were thermocycled (2500 cycles) and mechanically loaded (250,000 cycles) in a chewing simulator followed by static loading until failure, and the values noted. The data were statistically analyzed by 2-way ANOVA and Tukey HSD post-hoc multiple comparison tests (α = 0.05). The mean fracture loads ranged from 1022 to 1322 N for nanoceramic crowns and from 1145 to 1441 N for the lithium disilicate crowns. Two-way ANOVA revealed insignificant differences between the nanoceramic and lithium disilicate crowns (p > 0.05) in terms of fracture load. Significant differences were noted in the fracture resistance of crowns based on occlusal thickness (303 N; p = 0.013) regardless of the material used. Multiple comparisons by Tukey HSD post-hoc test showed insignificant differences between the four material-occlusal thickness groups (p > 0.05). The nanoceramic crowns were found to be comparable with lithium disilicate crowns in terms of fracture load. The mean fracture loads of all of the tested crowns were within the normal physiological masticatory load limits. Based on the fracture-resistance results, nanoceramic crowns seem to be suitable for clinical use for the tested occlusal thicknesses.
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Affiliation(s)
| | - Arwa Jamal Alloughani
- College of Dentistry, Kuwait University, Kuwait P.O. Box 24923, Kuwait; (F.A.A.); (A.J.A.)
| | - Mohammed Nasser Alhajj
- Department of Prosthodontics, Faculty of Dentistry, Thamar University, Dhamar P.O. Box 13020, Yemen;
| | - Mirza Rustum Baig
- Department of Restorative Sciences (Prosthodontics), College of Dentistry, Kuwait University, Kuwait P.O. Box 24923, Kuwait
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Yurchenko M, Hubálková H, Charvát J. Selected muscle tone and asymmetry of the occlusal plane in case of intracapsular temporomandibular joint disorder. Cranio 2024; 42:267-278. [PMID: 34355675 DOI: 10.1080/08869634.2021.1964052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Objective: To discover the extent of the connection between occlusal plane asymmetry and the rest tone of the four muscle groups of the orofacial region with temporomandibular joint pathology.Methods: Eighty-seven subjects were divided into two groups. The following methods were applied: clinical examination, roentgenological examination, and electromyography. Data were evaluated and statistically analyzed.Results: The variability of occlusal plane inclination in relation to the porion plane was 0-4.6º.The tonus of masseter muscle was higher in the experimental group: 1.45 mV more than in the control group: 1.23 mV (p < 0.05).Conclusion: Asymmetry of the occlusal plane inclination was found for nearly all subjects in both groups. It can be compensated for by adaptation mechanisms and does not cause temporomandibular joint disorders. Undertaken research shows the existence of a proven correlation between TMJ disorders and the resting tonus of the masseter muscle.
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Affiliation(s)
- Maksim Yurchenko
- Charles University in Prague, 1st Faculty of Medicine, Department Of Stomatology, Prague 2, Czech Republic
| | - Hana Hubálková
- Charles University in Prague, 1st Faculty of Medicine, Department Of Stomatology, Prague 2, Czech Republic
| | - Jindřich Charvát
- Charles University in Prague, 1st Faculty of Medicine, Department Of Stomatology, Prague 2, Czech Republic
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ElShamoty YK, Sadeqi HA, Baig MR. Effect of connector height and retainer occlusal thickness on the fracture resistance of posterior 4-unit monolithic 5Y-TZP fixed partial dentures after thermomechanical aging. J Prosthet Dent 2024; 131:933.e1-933.e7. [PMID: 38429151 DOI: 10.1016/j.prosdent.2024.01.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 03/03/2024]
Abstract
STATEMENT OF PROBLEM The connector height and retainer occlusal thickness of fixed partial dentures (FPDs) may affect restoration longevity. PURPOSE The purpose of this in vitro study was to determine and compare the fracture resistance of 4-unit monolithic 5% yttria tetragonal zirconia polycrystal (5Y-TZP) FPDs made with different connector heights and retainer occlusal thicknesses after thermomechanical aging. MATERIAL AND METHODS Forty test metal dies were duplicated from a master metal die containing 2 anatomic abutment preparations of the mandibular right first premolar and second molar for a 4-unit FPD. The dies were divided into 2 groups of 20 each for the fabrication of 4-unit FPDs, with 2-mm and 4-mm uniform connector heights at all 3 connectors, resulting in 6.3-mm2 and 12.6-mm2 connector areas. Each of these groups was further divided into 2 subgroups based on the occlusal thickness of the 2 retainers of 1 mm and 2 mm (n=10). Polyvinyl siloxane impressions of the test metal dies were made and poured in Type V dental stone. Laboratory scans were performed on all the stone dies, and 40 5Y-TZP FPDs (Ceramill Zolid FX) were designed and fabricated. Subsequently, all the FPDs were luted on to the metal dies with a self-adhesive resin cement. The FPDs were preloaded (400 000 mechanical cycles; 4000 thermocycles) using a mastication simulator and tested for axial compressive strength. Two-way analysis of variance (ANOVA) was used to examine the effect of connector and occlusal thicknesses on the fracture load (α=.05). The data were further assessed using the post hoc Tukey HSD multiple comparison test (α=.05). RESULTS The mean fracture load values were between 737 N and 1563 N. Significant differences in the mean fracture load were found between the connector heights (601 N; P<.001) and occlusal thicknesses (225 N; P=.002), but the interaction of the 2 factors was not significant (P=.132) The Tukey post hoc analysis showed significant differences between the connector thicknesses groups (P<.01), but the occlusal thicknesses were found to be similar for the same connector height (P=.609) CONCLUSIONS: Connector height and occlusal retainer thickness influenced the fracture load of 4-unit monolithic 5Y-TZP FPDs after thermomechanical aging.
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Affiliation(s)
- Yousef Khaled ElShamoty
- Graduate student, Dental Materials Science, Department of Bioclinical Sciences, College of Dentistry, Kuwait University, Kuwait City, Kuwait; and Ministry of Health, Kuwait
| | - Haneen Adnan Sadeqi
- Senior Dental Technician, Department of Restorative Sciences, College of Dentistry, Kuwait University, Kuwait City, Kuwait
| | - Mirza Rustum Baig
- Associate Professor, Department of Restorative Sciences (Prosthodontics), College of Dentistry, Kuwait University, Kuwait City, Kuwait.
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Hegedűs M, Kis VK, Rózsa N, Kovács Z. A novel image processing procedure for the quantitative evaluation of dental enamel prism arrangement. Microsc Res Tech 2024; 87:808-817. [PMID: 38093599 DOI: 10.1002/jemt.24473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 11/27/2023] [Indexed: 03/02/2024]
Abstract
Enamel prism is the main microstructural unit of mammalian enamel which composed of hundreds of bioapatite nanocrystals. Prism structure plays a key role in the excellent mechanical performance of dental enamel during millions of chewing cycles without significant remodeling. Thus, quantitative understanding of prism architecture is of utmost importance for biomechanical materials design. To characterize enamel prism orientation quantitatively, a novel image processing method has been developed. Our method is based on scanning electron microscopy images of etched enamel surface and consists of an ellipse fitting procedure, which provides a numerical approximation of prism shape and orientation in the studied cross section. The obtained analytical data allow to construct color coded orientation maps, which provide quick and useful insight into the microstructure of enamel. Besides striking visualization, orientation maps allow to extract and plot the rich information on the azimuthal and inclination angles of the prisms as function of location. Numerical data on prism arrangement can be analyzed using statistical tools over large areas, which paves the way towards quantifying comparative investigation of prism arrangement either in dentistry research or evolution biology. The application of the method is demonstrated for a distal-mesial cross-section of sound human tooth enamel. HIGHLIGHTS: Scanning electron microscopy images of etched enamel surface are analyzed using ellipse fitting. Geometrical parameters of the fitted ellipses provide numerical data of thousands of prisms. Prism arrangement is visualized on color coded orientation maps and analyzed using statistical tools.
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Affiliation(s)
- Máté Hegedűs
- Department of Materials Physics, Eötvös Loránd University, Budapest, Hungary
| | - Viktória K Kis
- HUN-REN Centre for Energy Research, Budapest, Hungary
- Department of Mineralogy, Eötvös Loránd University, Budapest, Hungary
| | - Noémi Rózsa
- Faculty of Dentistry, Department of Pedodontics and Orthodontics, Semmelweis University, Budapest, Hungary
| | - Zsolt Kovács
- Department of Materials Physics, Eötvös Loránd University, Budapest, Hungary
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Stoilov M, Boehmer T, Stoilov L, Stark H, Marder M, Enkling N, Kraus D. Influence of Cementation Mode and Ferrule Design on the Fatigue Resistance of Monolithic Zirconia Endocrowns. J Clin Med 2024; 13:1165. [PMID: 38398475 PMCID: PMC10889707 DOI: 10.3390/jcm13041165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 02/13/2024] [Accepted: 02/17/2024] [Indexed: 02/25/2024] Open
Abstract
Background: Classic endocrowns made of dental ceramics are considered a promising alternative to traditional post-endodontic restorations. The use of circular ferrules in endocrowns is a topic of controversial discussion. Therefore, the present study aims to evaluate the effect of ferrule design and cementation mode on the fatigue resistance of zirconia endocrowns. Methods: Eighty human molars were divided into four groups (n = 20): NFC (no-ferrule, conventional cementation), NFA (no-ferrule, adhesive luting), FC (ferrule, conventional cementation) and FA (ferrule, adhesive luting). Both the classic and the modified endocrown preparation with a two-millimeter ferrule design were carried out. Endocrowns were fabricated from zirconia using the CEREC system. After thermocycling, specimens were loaded according to the step-stress test up to 1500 N. Results: Failure rate was low; 88.8% of total specimens passed the step-stress test. Fractures were distributed between all groups; no significant differences in fatigue resistance were detected for preparation design and cementation mode. Conclusions: Endocrowns appear to be a promising concept for endodontically treated molars. Ferrule and also cementation mode have only a minor influence on fatigue resistance of zirconia endocrowns. However, at very high forces, the marginal area of the ferrule represents a weak point.
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Affiliation(s)
- Milan Stoilov
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, Bonn University, 53111 Bonn, Germany; (T.B.); (L.S.); (H.S.); (M.M.); (N.E.); (D.K.)
| | - Tobias Boehmer
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, Bonn University, 53111 Bonn, Germany; (T.B.); (L.S.); (H.S.); (M.M.); (N.E.); (D.K.)
| | - Lea Stoilov
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, Bonn University, 53111 Bonn, Germany; (T.B.); (L.S.); (H.S.); (M.M.); (N.E.); (D.K.)
| | - Helmut Stark
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, Bonn University, 53111 Bonn, Germany; (T.B.); (L.S.); (H.S.); (M.M.); (N.E.); (D.K.)
| | - Michael Marder
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, Bonn University, 53111 Bonn, Germany; (T.B.); (L.S.); (H.S.); (M.M.); (N.E.); (D.K.)
| | - Norbert Enkling
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, Bonn University, 53111 Bonn, Germany; (T.B.); (L.S.); (H.S.); (M.M.); (N.E.); (D.K.)
- Department of Reconstructive Dentistry and Gerodontology, Bern University, 3012 Bern, Switzerland
| | - Dominik Kraus
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, Bonn University, 53111 Bonn, Germany; (T.B.); (L.S.); (H.S.); (M.M.); (N.E.); (D.K.)
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Botelho AL, da Silva AMBR, da Silva MAMR, Cândido Dos Reis A. Assessment of neuromuscular fatigue through frequency analysis of the electromyographic signal of control participants and those with temporomandibular dysfunction treated with resilient or hard occlusal devices. J Prosthet Dent 2024; 131:233-240. [PMID: 35400505 DOI: 10.1016/j.prosdent.2021.12.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 12/12/2021] [Accepted: 12/13/2021] [Indexed: 10/18/2022]
Abstract
STATEMENT OF PROBLEM Muscle hyperactivity that leads to neuromuscular fatigue can be evaluated by electromyography. Whether treatment with occlusal devices can restore neuromuscular balance to patients with temporomandibular disorders (TMDs) is unclear. PURPOSE The purpose of this clinical study was to evaluate neuromuscular fatigue by analyzing the frequency of the electromyographic signal of the masseter and anterior temporalis muscles on both sides in healthy participants and those with TMD treated with a resilient or hard occlusal device. MATERIAL AND METHODS One hundred asymptomatic participants and 30 with TMD were divided into 2 groups: treated with a hard device or treated with a resilient device. All underwent electromyographic examination before and after treatment with the occlusal devices. RESULTS In both groups, the results showed statistically significant differences (P<.01) when the fatigue rate before and after treatment with an occlusal device was compared. CONCLUSIONS Treatment with both types of occlusal device was efficient in reducing the rate of neuromuscular fatigue in patients with TMDs.
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Affiliation(s)
- André Luís Botelho
- Post-Doc student, Department of Dental Materials and Prosthodontics, Ribeirão Preto Dental School, University of São Paulo (USP), Ribeirão Preto, SP, Brazil.
| | | | | | - Andréa Cândido Dos Reis
- Professor, Department of Dental Materials and Prosthodontics, Ribeirão Preto Dental School, University of São Paulo (USP), Ribeirão Preto, SP, Brazil
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Gierthmuehlen PC, Spitznagel FA, Koschate M, Bonfante EA, Prott LS. Influence of ceramic thickness and dental substrate on the survival rate and failure load of non-retentive occlusal veneers after fatigue. J ESTHET RESTOR DENT 2024; 36:373-380. [PMID: 37605963 DOI: 10.1111/jerd.13103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 04/26/2023] [Accepted: 06/27/2023] [Indexed: 08/23/2023]
Abstract
OBJECTIVE To investigate the effect of ceramic thickness and dental substrate (enamel vs. dentin/enamel) on the survival rate and failure load of non-retentive occlusal veneers. MATERIALS AND METHODS Human maxillary molars (n = 60) were divided into five test-groups (n = 12). The groups (named DE-1.5, DE-1.0, DE-0.5, E-1.0, E-0.5) differed in their dental substrate (E = enamel, DE = dentin/enamel) and restoration thickness (standard: 1.5 mm, thin: 1.0 mm, ultrathin: 0.5 mm). All teeth were prepared for non-retentive monolithic lithium-disilicate occlusal veneers (IPS e.max Press, Ivoclar). Restorations were adhesively cemented (Syntac Classic/Variolink II, Ivoclar) and exposed to thermomechanical fatigue (1.2 million cycles, 1.6 Hz, 49 N/ 5-55°C). Single load to failure was performed using a universal testing-machine. A linear-regression model was applied, pairwise comparisons used the Student-Newman-Keuls method (p < 0.05). RESULTS Three dentin-based occlusal veneers (one DE-1.0, two DE-0.5) revealed cracks after fatigue exposure, which corresponds to an overall-survival rate of 95%. Load to failure resulted in the following ranking: 2142 N(DE-0.5) > 2105 N(E-1.0) > 2075 N(E-0.5) > 1440 N(DE-1.5) > 1430 N(DE-1.0). Thin (E-1.0) and ultrathin enamel-based occlusal veneers (E-0.5) revealed high failure loads and surpassed the standard thickness dentin-based veneers (DE-1.5) significantly (p = 0.044, p = 0.022). CONCLUSION All tested monolithic lithium disilicate occlusal veneers obtained failure loads above physiological chewing forces. Thin and ultrathin enamel-based occlusal veneers outperformed the standard thick dentin-based occlusal veneers. CLINICAL SIGNIFICANCE Minimally invasive enamel-based occlusal veneer restorations with non-retentive preparation design may serve as a conservative treatment option.
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Affiliation(s)
- Petra C Gierthmuehlen
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
| | - Frank A Spitznagel
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
| | | | - Estevam A Bonfante
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of Sao Paulo, Bauru, SP, Brazil
| | - Lea S Prott
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
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Bogdanov V. Type of correlation between bite force and EMG activity of the temporalis and masseter muscles during maximal and submaximal clenching. Folia Med (Plovdiv) 2023; 65:975-985. [PMID: 38351788 DOI: 10.3897/folmed.65.e107180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 08/24/2023] [Indexed: 02/16/2024] Open
Abstract
INTRODUCTION Maximal bite force is an important determinant of masticatory function and is essential for the estimation of dental status. Bite force is usually measured by gnathodynamometry.
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Mohseni P, Soufi A, Chrcanovic BR. Clinical outcomes of zirconia implants: a systematic review and meta-analysis. Clin Oral Investig 2023; 28:15. [PMID: 38135804 PMCID: PMC10746607 DOI: 10.1007/s00784-023-05401-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023]
Abstract
PURPOSE To assess the clinical outcomes of zirconia dental implants based on an updated systematic literature review. METHODS An electronic search was performed in three databases, last updated in June 2023, supplemented by hand searching. The eligibility criteria were clinical studies reporting patients rehabilitated with zirconia implants. The cumulative survival rate (CSR) of implants was calculated. A meta-analysis for marginal bone loss (MBL) under different follow-up times and a meta-regression assessing the relationship between mean MBL and follow-up were done. RESULTS Twenty-five studies were included (4017 implants, 2083 patients). Seven studies had follow-up longer than 60 months. 172 implants failed, after a mean of 12.0 ± 16.1 months (min-max 0.3-86.0), of which 47 early failures, and 26 due to implant fracture, the majority in narrow-diameter implants. The 10-year CSR was 95.1%. Implants with coronal part prepared by drills presented statistically significant lower survival than non-prepared implants (p < 0.001). Two-piece implants presented lower survival than one-piece implants (p = 0.017). Implants discontinued from the market presented lower survival than the commercially available ones (p < 0.001). The difference in survival was not significant between implants in maxilla and mandible (p = 0.637). The mean MBL fluctuated between 0.632 and 2.060 mm over long periods of observation (up until 132 months). There was an estimated MBL increase of 0.005 mm per additional month of follow-up. CONCLUSION Zirconia implants present high 10-year CSR and short-term low MBL. The review was registered in PROSPERO (CRD42022342055). CLINICAL RELEVANCE The clinical outcomes observed for zirconia dental implants are very promising, although these have not yet been extensively studied as titanium alloy implants.
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Affiliation(s)
| | - Ahmad Soufi
- Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Bruno Ramos Chrcanovic
- Department of Oral and Maxillofacial Surgery and Oral Medicine, Faculty of Odontology, Malmö University, Carl Gustafs Väg 34, 214 21, Malmö, Sweden.
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Oppen D, Weiss J. Oral processing, rheology, and mechanical response: Relations in a two-phase food model with anisotropic compounds. J Texture Stud 2023; 54:808-823. [PMID: 37718549 DOI: 10.1111/jtxs.12799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 08/15/2023] [Accepted: 08/30/2023] [Indexed: 09/19/2023]
Abstract
Food-material poses a challenging matrix for objective material scientific description that matches the consumers' perception. With eyes on the emerging structured food materials from alternative protein sources, objectively describing perceived texture characteristics became a topic of interest to the food industry. This work made use of the well-known methodologies of jaw tracking and electromyography from the field of "food oral processing" and compared outcomes with mechanical responses to the deformation of model food systems to meat alternatives. To enable transferability to meat alternative products, an anisotropic structuring ingredient for alternative products, high-moisture texturized vegetable protein (HM-TVP), was embedded in an isotropic hydrocolloid gel. Data of the jaw movement and muscle activities exerted during mastication were modeled in a linear mixed model and set in relation to characteristic values obtained from small- and large-strain deformation. For improvement of the model fit, this work makes use of two new data-processing strategies in the field of oral processing: (i) Muscle activity data were set in relation to true forces and (ii) measured data were standardized and subjected to dimensional reduction. Based on that, model terms showed decreased p-values on various oral processing features. As a key outcome, it could be shown that an anisotropic structured phase induces more lateral jaw movement than isotropic samples, as was shown in meat model systems.
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Affiliation(s)
- Dominic Oppen
- Department of Food Material Science, Institute of Food Science and Biotechnology, University of Hohenheim, Stuttgart, Germany
| | - Jochen Weiss
- Department of Food Material Science, Institute of Food Science and Biotechnology, University of Hohenheim, Stuttgart, Germany
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12
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Neves BR, Costa RTF, Vasconcelos BCDE, Pellizzer EP, Moraes SLD. Muscle activity between dentate and edentulous patients rehabilitated with dental prostheses: A systematic review. J Oral Rehabil 2023; 50:1508-1517. [PMID: 37605296 DOI: 10.1111/joor.13564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/18/2023] [Accepted: 07/31/2023] [Indexed: 08/23/2023]
Abstract
BACKGROUND Adequate muscle activity is important for the success of oral rehabilitation: it maintains the integrity of the stomatognathic system and is responsible for chewing movements needed to break, crush and grind food. OBJECTIVE To compare muscle activity using electromyography (EMG) while clenching or chewing soft and/or hard foods among individuals with natural dentition (ND) and edentulous patients rehabilitated with dental prostheses. METHODS This review was conducted until March, 2023, and the research question was "Is the muscle activity of edentulous patients rehabilitated with dental prostheses similar to that of dentate individuals?" A search strategy was conducted in PubMed/MEDLINE, The Cochrane Library, Web of Science, Lilacs, Embase and manual journal searches. RESULTS Ten studies were included in the analysis. Most of them reported that individuals with ND had significant higher muscle activity (clenching or chewing) than complete dentures (CD) users. However, no difference was observed between patients with full mouth implant-supported fixed dental prosthesis (ISFDP) and ND. Additionally, two studies compared patients with mandibular ISFDP with maxillary CD and individuals with ND and found no differences; however, one study concluded that patients with ISFDP with CD (maxillary or mandibular) had lower muscle activity than individuals with ND. Only one study reported a higher muscle activity in patients with full-mouth ISFDP than in individuals with ND. CONCLUSIONS Bimaxillary CD users had lower muscle activity than individuals with ND. During rehabilitation, the muscle activity of patients with full-mouth ISFDP and mandibular ISFDP with maxillary CD is similar to individuals with ND.
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Affiliation(s)
- Bruna Rocha Neves
- Department of Oral Rehabilitation, Faculty of Dentistry, University of Pernambuco (UPE), Recife, Brazil
| | | | | | - Eduardo Piza Pellizzer
- Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University (UNESP), Araçatuba, Brazil
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Wang JL, Wang J, Chen KN, Guo JQ, Xu XL, Guo CB. Designing customized temporomandibular fossa prosthesis based on envelope surface of condyle movement: validation via in silico musculoskeletal simulation. Front Bioeng Biotechnol 2023; 11:1273263. [PMID: 38026896 PMCID: PMC10644477 DOI: 10.3389/fbioe.2023.1273263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Objective: This study presents an innovative articular fossa prosthesis generated by the envelope surface of condyle movement, and compares its mandible movements, muscle activities, and joint reaction forces with two temporomandibular joint (TMJ) prostheses using multibody musculoskeletal simulation. Methods: A healthy 23-year-old female was recruited for this study. Cone-beam computed tomographic (CBCT) was performed to reconstruct the mandibular bone geometry. A customized TMJ fossa prosthesis was designed based on the subject-specific envelope surface of condyle movement (ESCM). Mandibular kinematics and jaw-closing muscle electromyography (EMG) were simultaneously recorded during maximum jaw opening-closing movements. To validate our prosthesis design, a mandibular musculoskeletal model was established using flexible multibody dynamics and the obtained kinematics and EMG data. The Biomet fossa prosthesis and the ellipsoidal fossa prosthesis designed by imitating the lower limb prostheses were used for comparison. Simulations were performed to analyze the effects of different fossa prostheses on jaw opening-closing motions, mandibular muscle activation, and contact forces. Results: The maximum opening displacement for the envelope-based fossa prosthesis was greater than those for Biomet and ellipsoidal prostheses (36 mm, 35 mm, and 33 mm, respectively). The mandibular musculoskeletal model with ellipsoidal prosthesis led to dislocation near maximal jaw opening. Compared to Biomet, the envelope-based fossa reduced the digastric and lateral pterygoid activation at maximal jaw opening. It also reduced the maximal resistance to condylar sliding on the intact side by 63.2 N. Conclusion: A customized TMJ fossa prosthesis was successfully developed using the ESCM concept. Our study of musculoskeletal multibody modeling has highlighted its advantages and potential. The artificial fossa design successfully achieved a wider condylar range of motion. It also reduced the activation of jaw opening muscles on the affected side and resistance on the intact side. This study showed that an ESCM-based approach may be useful for optimizing TMJ fossa prostheses design.
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Affiliation(s)
- Jun-Lin Wang
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry, Ministry of Health, NMPA Key Laboratory for Dental Materials, Beijing, China
| | - Jing Wang
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry, Ministry of Health, NMPA Key Laboratory for Dental Materials, Beijing, China
| | - Ke-Nan Chen
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry, Ministry of Health, NMPA Key Laboratory for Dental Materials, Beijing, China
| | - Jian-Qiao Guo
- MOE Key Laboratory of Dynamics and Control of Flight Vehicle, School of Aerospace Engineering, Beijing Institute of Technology, Beijing, China
| | - Xiang-Liang Xu
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry, Ministry of Health, NMPA Key Laboratory for Dental Materials, Beijing, China
| | - Chuan-Bin Guo
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry, Ministry of Health, NMPA Key Laboratory for Dental Materials, Beijing, China
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Kashiwazaki K, Komagamine Y, Shanglin W, Ren X, Hayashi N, Nakayama M, Namano S, Kanazawa M, Minakuchi S. Improvements in Maximum Bite Force with Gum-Chewing Training in Older Adults: A Randomized Controlled Trial. J Clin Med 2023; 12:6534. [PMID: 37892673 PMCID: PMC10607538 DOI: 10.3390/jcm12206534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/25/2023] [Accepted: 10/12/2023] [Indexed: 10/29/2023] Open
Abstract
No specific methods have been officially proposed for the prevention and improvement of oral hypofunction. Therefore, in this randomized controlled trial, we aimed to develop a gum-chewing training program and determine its effects in older adults. A total of 218 older adults, aged 65-85 years, were randomly allocated to the intervention or control groups. The intervention group chewed the experimental gum daily, whereas the control group consumed the experimental granular food daily. The outcome assessments measured the maximum bite force, occlusal contact areas, oral dryness, tongue pressure, tongue and lip functions, masticatory function, and gum-chewing time. The measured values for each outcome were compared between groups using the Mann-Whitney U test and within groups pre- and post-intervention using the Wilcoxon signed-rank test. A total of 211 participants completed the study. After 2 months, the intervention group had a significantly higher maximum bite force than the control group (p = 0.01), indicating that gum-chewing training improved maximum bite force in older adults. This was determined using one type of bite force measuring device. Therefore, it is suggested that gum-chewing training has a high potential to improve oral hypofunction.
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Affiliation(s)
- Kenta Kashiwazaki
- Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8549, Japan; (K.K.); (W.S.); (X.R.); (S.N.); (S.M.)
| | - Yuriko Komagamine
- Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8549, Japan; (K.K.); (W.S.); (X.R.); (S.N.); (S.M.)
| | - Wu Shanglin
- Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8549, Japan; (K.K.); (W.S.); (X.R.); (S.N.); (S.M.)
| | - Xiangyu Ren
- Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8549, Japan; (K.K.); (W.S.); (X.R.); (S.N.); (S.M.)
| | - Nanaka Hayashi
- Digital Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8549, Japan; (N.H.); (M.N.); (M.K.)
| | - Mirai Nakayama
- Digital Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8549, Japan; (N.H.); (M.N.); (M.K.)
| | - Sahaprom Namano
- Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8549, Japan; (K.K.); (W.S.); (X.R.); (S.N.); (S.M.)
| | - Manabu Kanazawa
- Digital Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8549, Japan; (N.H.); (M.N.); (M.K.)
| | - Shunsuke Minakuchi
- Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8549, Japan; (K.K.); (W.S.); (X.R.); (S.N.); (S.M.)
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15
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Leung BAY, Joe W, Mofarah SS, Sorrell CC, Abbasi R, Azadeh M, Arsecularatne JA, Koshy P. Unveiling the mechanisms behind surface degradation of dental resin composites in simulated oral environments. J Mater Chem B 2023; 11:7707-7720. [PMID: 37465918 DOI: 10.1039/d3tb00756a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Dental resin composites are widely used as restorative materials due to their natural aesthetic and versatile properties. However, there has been limited research on the degradation mechanisms of these composites in gastric acid environments, which would be common in patients with gastroesophageal reflux. This study aims to investigate the degradation behavior of dental composites immersed in simulated oral environments, including acid, saliva, and water. Mechanical and morphological properties of the composites, upon immersion in the simulated environments, were thoroughly examined using hardness testing and SEM imaging. Qualitative analyses of the ions leached from the polymer matrix and fillers were conducted using XPS and ICP-MS. In addition, the thermodynamic stability of the inorganic fillers of the composites in aqueous solutions across a wide range of pH values was theoretically studied through construction of Pourbaix diagrams. This study proposed a mechanism for composite leaching involving interactions between the matrix's hydrophilic groups and the aqueous immersion media, leading to swelling and chemical degradation of the composites. Furthermore, it was demonstrated that filler leaching was followed by ion exchange with Ca and P, resulting in the formation of hard calcified layers on the composite surface. The current findings provide valuable insights into the development of new composite materials with improved durability and resistance to degradation, especially for patients suffering from gastroesophageal reflux.
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Affiliation(s)
- Brenda Ah-Yan Leung
- School of Materials Science and Engineering, UNSW Sydney, NSW 2052, Australia.
| | - William Joe
- School of Materials Science and Engineering, UNSW Sydney, NSW 2052, Australia.
| | - Sajjad S Mofarah
- School of Materials Science and Engineering, UNSW Sydney, NSW 2052, Australia.
| | - Charles C Sorrell
- School of Materials Science and Engineering, UNSW Sydney, NSW 2052, Australia.
| | - Roozbeh Abbasi
- School of Materials Science and Engineering, UNSW Sydney, NSW 2052, Australia.
| | - Mohsen Azadeh
- School of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran
| | | | - Pramod Koshy
- School of Materials Science and Engineering, UNSW Sydney, NSW 2052, Australia.
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Saracutu OI, Pollis M, Cagidiaco EF, Ferrari M, Manfredini D. Repeatability of Teethan® indexes analysis of the masseter and anterior temporalis muscles during maximum clenching: a pilot study. Clin Oral Investig 2023; 27:5309-5316. [PMID: 37507600 PMCID: PMC10492765 DOI: 10.1007/s00784-023-05150-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023]
Abstract
OBJECTIVES The aim of this study is to assess the repeatability of a surface electromyographic (EMG) device (Teethan®, Teethan S.p.A., Milan, Italy), designed for the analysis of the masseter and anterior temporalis muscles. MATERIALS AND METHODS Tests were performed on a sample of 30 healthy fully dentate TMD-free individuals randomly selected. Each test consisted of two distinct recordings performed at 5-min intervals: (i) the patient is asked to clench with maximum voluntary contraction (MVC), with two cotton rolls interposed between the dental arches; (ii) the patient is asked to repeat the same clenching activity without the cotton rolls. The outcomes of the study were the EMG indices conceptualized by the manufacturing company, based on the differences between the two test conditions (i.e., clenching on cotton rolls and on dentition). Pairwise correlation analysis and ANOVA test were performed to assess the strength of correlation and the significance of differences between the results of the three trials. RESULTS Thirty TMD-free healthy individuals (20 females and 10 males; mean age 44 years, range 16-60 years) took part in the study. ANOVA test did not show any statistically significant difference between the three trials. The Global Index, which is the mean of the other EMG indices, showed the highest correlation values between the three trials, while some other indices showed a weak-to-medium correlation level. One out of five participants showed a coefficient of variation higher than 10%. CONCLUSIONS The statistical analysis showed that the indices provided by the device are quite repeatable. However, this does not necessarily imply a specific clinical application of the device, which was here used in fully controlled experimental conditions. CLINICAL RELEVANCE The clinical usefulness of the applied protocol remains questionable. Further studies should test the repeatability of EMG findings gathered with this device under various circumstances, in a more heterogeneous population.
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Affiliation(s)
- Ovidiu Ionut Saracutu
- Department of Biomedical Technologies, School of Dentistry, University of Siena, 53100, Siena, Italy.
| | - Matteo Pollis
- Department of Biomedical Technologies, School of Dentistry, University of Siena, 53100, Siena, Italy
| | - Edoardo Ferrari Cagidiaco
- Department of Biomedical Technologies, School of Dentistry, University of Siena, 53100, Siena, Italy
| | - Marco Ferrari
- Department of Biomedical Technologies, School of Dentistry, University of Siena, 53100, Siena, Italy
| | - Daniele Manfredini
- Department of Biomedical Technologies, School of Dentistry, University of Siena, 53100, Siena, Italy
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17
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Emam M, Metwally MF. Effect of coping materials zirconia or polyetheretherketone with different techniques of fabrication on vertical marginal gap and fracture resistance of posterior crowns with composite veneering. BMC Oral Health 2023; 23:546. [PMID: 37559037 PMCID: PMC10413631 DOI: 10.1186/s12903-023-03247-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 07/21/2023] [Indexed: 08/11/2023] Open
Abstract
BACKGROUND Insufficient research has been conducted in the literature assessing the performance of zirconia and polyetheretherketone (PEEK) crowns in relation to the essential requirements of successful restorations, such as fracture resistance or margin adaptation. The purpose of this study was to evaluate the effect of the coping materials zirconia or PEEK with different fabrication techniques on the vertical marginal gap and fracture resistance of posterior crowns with composite veneering. METHODS Ceramic copings (n = 18) restoring mandibular first molar were fabricated from zirconia (Zircon.x, Presidentdental, Germany), milled PEEK (PEEK CAD) (breCAM.BioHPP, Bredent, Germany) and pressed PEEK (PEEK Press) (BioHPP Granules, Bredent, Germany) six specimens each (n = 6). The copings were veneered with high impact polymer composite (HIPC) material (breCAM.HIPC, Bredent, Germany). The vertical marginal gap was captured under a magnification of 40X. Five equidistant marks on each surface of the die distinguished the points of measurement for a total of 20 readings per sample. The analysis was completed using an image analysis system (ImageJ 1.53t, National Institute of Health, USA). The specimens were loaded to failure at a crosshead speed of 1 mm/min and the load at failure was recorded to measure the fracture resistance. RESULTS The marginal gap was analyzed using one-way ANOVA followed by Tukey's post hoc test. Fracture resistance was analyzed using Welch one-way ANOVA followed by the Games-Howell post hoc test. Marginal gap values showed a significant difference between the tested groups, with zirconia having significantly lower gap values (48.67 ± 11.98 µm) than both the PEEK CAD (108.00 ± 20.08 µm) and Press groups (108.00 ± 25.10 µm) (p < 0.001). However, the results of fracture resistance showed no significant difference (p = 0.06) with 1687.47 ± 253.29 N, 2156.82 ± 407.64 N, 2436.72 ± 725.93 N for zirconia, PEEK CAD, and Press, respectively. The significance level was p < 0.05. CONCLUSIONS Zirconia framework crowns have a smaller vertical marginal gap than milled and pressed PEEK crowns. Crowns fabricated from zirconia, PEEK CAD, or PEEK Press frameworks and veneered with composite resin have comparable fracture resistance lower than the maximum biting force in the posterior region. CLINICAL RELEVANCE Posterior crowns with zirconia frameworks are preferred over milled and pressed PEEK frameworks regarding margin adaptation, although all can safely survive the maximum occlusal forces without fracture.
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Affiliation(s)
- Marwa Emam
- Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Organization of African Unity St, El-Qobba Bridge, Al Waili, 11566, Cairo, Egypt.
| | - Mohamed F Metwally
- Department of Crown and Bridge, Faculty of Dental Medicine, AL Azhar University, Cairo, Egypt
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18
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Osman MLM, Lim TW, Chang HC, Ab Ghani AR, Tsoi JKH, Ab Ghani SM. Structural Integrity of Anterior Ceramic Resin-Bonded Fixed Partial Denture: A Finite Element Analysis Study. J Funct Biomater 2023; 14:jfb14020108. [PMID: 36826907 PMCID: PMC9962904 DOI: 10.3390/jfb14020108] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
This study was conducted as a means to evaluate the stress distribution patterns of anterior ceramic resin-bonded fixed partial dentures derived from different materials and numerous connector designs that had various loading conditions imposed onto them through the utilization of the finite element method. A finite element model was established on the basis of the cone beam computed tomography image of a cantilevered resin-bonded fixed partial denture with a central incisor as an abutment and a lateral incisor as a pontic. Sixteen finite element models representing different conditions were simulated with lithium disilicate and zirconia. Connector height, width, and shape were set as the geometric parameters. Static loads of 100 N, 150 N, and 200 N were applied at 45 degrees to the pontic. The maximum equivalent stress values obtained for all finite element models were compared with the ultimate strengths of their materials. Higher load exhibited greater maximum equivalent stress in both materials, regardless of the connector width and shape. Loadings of 200 N and 150 N that were correspondingly simulated on lithium disilicate prostheses of all shapes and dimensions resulted in connector fractures. On the contrary, loadings of 200 N, 150 N, and 100 N with rectangular-shaped connectors correspondingly simulated on zirconia were able to withstand the loads. However, two of the trapezoidal-shaped zirconia connectors were unable to withstand the loads and resulted in fractures. It can be deduced that material type, shape, and connector dimensions concurrently influenced the integrity of the bridge.
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Affiliation(s)
- Mas Linda Mohd Osman
- Centre of Restorative Dentistry Studies, Faculty of Dentistry, Universiti Teknologi MARA, Sungai Buloh 47000, Selangor, Malaysia
| | - Tong Wah Lim
- Division of Restorative Dental Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China
| | - Hung-Chih Chang
- Department of Biomedical Engineering, Hungkuang University, Taichung City 433304, Taiwan
| | - Amir Radzi Ab Ghani
- College of Engineering, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
| | - James Kit Hon Tsoi
- Division of Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China
| | - Siti Mariam Ab Ghani
- Centre of Restorative Dentistry Studies, Faculty of Dentistry, Universiti Teknologi MARA, Sungai Buloh 47000, Selangor, Malaysia
- Correspondence: ; Tel.: +86-603-61266611
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Role of Electromyography in Dental Research:
A Review. JOURNAL OF RESEARCH IN DENTAL AND MAXILLOFACIAL SCIENCES 2023. [DOI: 10.52547/jrdms.8.1.71] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
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20
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Sonaye SY, Bokam VK, Saini A, Nayak VV, Witek L, Coelho PG, Bhaduri SB, Bottino MC, Sikder P. Patient-specific 3D printed Poly-ether-ether-ketone (PEEK) dental implant system. J Mech Behav Biomed Mater 2022; 136:105510. [PMID: 36244326 DOI: 10.1016/j.jmbbm.2022.105510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/29/2022] [Accepted: 10/02/2022] [Indexed: 11/06/2022]
Abstract
Fused Filament Fabrication (FFF)-based 3D printing is an efficient technique for developing medical implants, but it is not very useful in developing small yet mechanically robust design-specific fixtures such as dental implants (<15 mm). Specifically, it is challenging to 3D print robust Polyetheretherketone (PEEK) small implants due to PEEK's high melting temperature and melt viscosity. However, in this study, we efficiently utilize high-temperature FFF to develop the first-of-its-kind patient-specific robust PEEK dental implants with high print resolution. Specifically, we explore the effects of critical FFF processing conditions on the mechanical properties of the implants and subsequently determine an optimized set of processing conditions that are essential in developing durable dental implant systems. Our results indicate that the 3D printed dental implants exhibit good fatigue properties and suffice the clinical and industrial requirements for dental implants. Furthermore, we prove that the 3D printed implants exhibit adequate mechanical durability even after simulated (accelerated) aging of 30 years.
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Affiliation(s)
| | - Vijay K Bokam
- Department of Mechanical Engineering, Cleveland State University, Cleveland, OH, USA
| | - Akshay Saini
- Department of Mechanical Engineering, Cleveland State University, Cleveland, OH, USA
| | - Vasudev V Nayak
- Department of Mechanical and Aerospace Engineering, New York University Tandon School of Engineering, Brooklyn, NY, USA; Biomaterials Division - Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, USA
| | - Lukasz Witek
- Biomaterials Division - Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, USA; Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, NY, USA
| | - Paulo G Coelho
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA; Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Sarit B Bhaduri
- Department of Mechanical, Industrial and Manufacturing Engineering, University of Toledo, Toledo, OH, USA
| | - Marco C Bottino
- Department of Cariology, Restorative Sciences, Endodontics, School of Dentistry, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Prabaha Sikder
- Department of Mechanical Engineering, Cleveland State University, Cleveland, OH, USA.
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Jung JK, Im YG. Can the subject reliably reproduce maximum voluntary contraction of temporalis and masseter muscles in surface EMG? Cranio 2022:1-10. [PMID: 36334278 DOI: 10.1080/08869634.2022.2142234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To evaluate the repeatability of the surface EMG variables of myoelectric signals from the masseter and temporalis muscles according to three methods to induce maximum voluntary contraction (MVC) in healthy adults. METHODS Thirty healthy young subjects performed the following three MVC tasks three times each in three sessions on the same day without replacing surface electrodes: clenching the teeth (MVCIC) and biting down on two cotton rolls bilaterally with the posterior teeth (MVCBP) or first molars (MVCB6). RESULTS The intra-class correlation coefficient (ICC) of the amplitudes during the three MVC tasks ranged from 65 to 79%. The ICCs of the spectral variables ranged from 78 to 86%. The ICCs of the asymmetry index of the masseter ranged from 77 to 86%, and those of the activity index ranged from 68 to 90%. CONCLUSION The surface EMG measurements according to the three MVC methods exhibited good to excellent reproducibility.
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Affiliation(s)
- Jae-Kwang Jung
- Department of Oral Medicine, School of Dentistry, IHBR, Kyungpook National University, Daegu, Republic of Korea
| | - Yeong-Gwan Im
- Department of Oral Medicine, Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea
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Zhou Z, Han X, Gao W, Li Y, Yu W, Yang S, Zhang J, Wang J, Shi R, Zhou Y, Zhao J. Fabrication and mechanical properties of different types of carbon fiber reinforced polyetheretherketone: A comparative study. J Mech Behav Biomed Mater 2022; 135:105472. [PMID: 36162163 DOI: 10.1016/j.jmbbm.2022.105472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/14/2022] [Accepted: 09/17/2022] [Indexed: 11/17/2022]
Abstract
OBJECTIVES To find alternative non-metallic materials as dental implants for clinical application, different types of carbon fiber reinforced polyetheretherketone were fabricated and investigated. METHODS Continuous carbon fiber reinforced polyetheretherketone fabrics were fabricated with polyetheretherketone fibers and carbon fibers. Different kinds of carbon fiber reinforced polyetheretherketone were synthesized by setting specific experiment parameters of injection or hot press molding. Various mechanical tests were performed to determine the mechanical properties of different carbon fiber reinforced polyetheretherketone, pure polyetheretherketone and pure titanium. RESULTS Polyetheretherketone composites presented outstanding mechanical and thermal properties after incorporating carbon fiber. The bending and tensile strength of short carbon fiber reinforced polyetheretherketone were close to human bone, and the bending strength of continuous carbon fiber reinforced polyetheretherketone reached 644 MPa, even higher than that of pure titanium. CONCLUSIONS The mechanical properties of polyetheretherketone composites are more similar to bone tissue than titanium, and the stress shielding phenomenon may be inhibited. They may become promising materials as substitutions for titanium and prospective materials in bone tissue engineering.
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Affiliation(s)
- Zhe Zhou
- Hospital of Stomatology, Jilin University, Changchun, 130021, China
| | - Xiao Han
- Hospital of Stomatology, Jilin University, Changchun, 130021, China
| | - Weijia Gao
- Hospital of Stomatology, Jilin University, Changchun, 130021, China
| | - Yongli Li
- Hospital of Stomatology, Jilin University, Changchun, 130021, China
| | - Wanqi Yu
- Hospital of Stomatology, Jilin University, Changchun, 130021, China
| | - Shihui Yang
- Hospital of Stomatology, Jilin University, Changchun, 130021, China
| | - Jingjie Zhang
- Hospital of Stomatology, Jilin University, Changchun, 130021, China
| | - Junyan Wang
- Hospital of Stomatology, Jilin University, Changchun, 130021, China
| | - Ruining Shi
- Hospital of Stomatology, Jilin University, Changchun, 130021, China
| | - Yanmin Zhou
- Hospital of Stomatology, Jilin University, Changchun, 130021, China; Jilin Province Key Laboratory of Tooth Development and Bone Remodeling, Changchun, 130021, China
| | - Jinghui Zhao
- Hospital of Stomatology, Jilin University, Changchun, 130021, China; Jilin Province Key Laboratory of Tooth Development and Bone Remodeling, Changchun, 130021, China.
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Fracture Resistance of Monolithic Zirconia Crowns Depending on Different Marginal Thicknesses. MATERIALS 2022; 15:ma15144861. [PMID: 35888327 PMCID: PMC9323601 DOI: 10.3390/ma15144861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 07/11/2022] [Accepted: 07/11/2022] [Indexed: 02/04/2023]
Abstract
Under some clinical conditions, the preparation of crowns of limited marginal thickness is inevitable. In such situations, it is questionable whether the same ideal preparation criteria can be applied equally. Since there are only a small number of studies focusing on the fracture resistance with respect to the marginal thickness, there is a need for a study evaluating whether zirconia crowns of limited marginal thickness are clinically acceptable. The purpose of this study is to evaluate the fracture resistance of monolithic zirconia crowns of limited marginal thickness in the posterior area. Methods: Abutments and CAD/CAM zirconia crowns with a marginal thickness of 1.0 mm were set as the control group, while experimental groups A, B, and C possessed reduced marginal thicknesses of 0.8 mm, 0.6 mm, and 0.4 mm, respectively (n = 10 per group). Resin-based abutment dies and monolithic zirconia crowns were fabricated using the CAD/CAM technique, and a universal testing machine was used to measure the fracture load value. Fractured specimens were examined with a scanning electron microscope. The data were analyzed using a one-way ANOVA and Bonferroni post hoc test (p < 0.05). Results: The means and standard deviations of the fracture load values of the control group and the three experimental groups were as follows: control group (1.0 mm): 3090.91 ± 527.77 N; group A (0.8 mm): 2645.39 ± 329.21 N; group B (0.6 mm): 2256.85 ± 454.15 N; group C (0.4 mm): 1957.8 ± 522.14 N. Conclusions: The crowns fabricated with a CAD/CAM zirconia block with limited marginal thicknesses of 0.6 mm and 0.4 mm showed significantly lower fracture resistance values compared to those with the recommended margin thickness of 1.0 mm.
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Guo J, Chen J, Wang J, Ren G, Tian Q, Guo C. EMG-assisted forward dynamics simulation of subject-specific mandible musculoskeletal system. J Biomech 2022; 139:111143. [DOI: 10.1016/j.jbiomech.2022.111143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/17/2022] [Accepted: 05/09/2022] [Indexed: 01/17/2023]
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Hjerppe J, Jung RE, Hämmerle CH, Özcan M, Mühlemann S. Mechanical stability of fully personalized, abutment-free zirconia implant crowns on a novel implant-crown interface. J Dent 2022; 121:104121. [PMID: 35395344 DOI: 10.1016/j.jdent.2022.104121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 03/24/2022] [Accepted: 04/03/2022] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES To test the failure load and failure mode of a novel implant-crown interface specifically designed for the fabrication of fully personalized, abutment-free monolithic zirconia CAD-CAM crowns compared to conventional implant-abutment interfaces involving prefabricated or centrally manufactured abutments for zirconia CAD-CAM crowns. METHODS Implants (N=48) were divided into groups (n=12) according to different implant-abutment interface designs: (1) internal implant connection with personalized, abutment-free CAD-CAM crowns (Abut-Free-Zr), (2) internal conical connection with customized, centrally manufactured zirconia CAD-CAM abutments (Cen-Abut-Zr), (3) prefabricated titanium base abutments from manufacturer 1 (Ti-Base-1), (4) additional prefabricated titanium base abutments from manufacturer 2 (Ti-Base-2). All specimens were restored with a screw-retained monolithic zirconia CAD-CAM molar crown and subjected to thermomechanical aging (1.200.000 cycles, 49 N, 1.67 Hz, 30° angulation, thermocycling 5-50°C). Static load until failure was applied in a universal testing machine. Failure modes were analyzed descriptively under digital microscope. Mean failure load values were statistically analyzed at a significance level of p<0.05. RESULTS All specimens survived thermomechanical aging. The mean failure loads varied between 1332 N (Abut-Free-Zr) and 1601 N (Ti-Base-2), difference being significant between these groups (p<0.05). No differences between the other groups were seen. The predominant failure mode per group was crown fracture above implant connection (Abut-Free-Zr, 75%), abutment fracture below implant neck (Cen-Abut-Zr, 83%), crown fracture leaving an intact abutment (Ti-Base-1/Ti-Base-2 100%). CONCLUSIONS Implant-crown interface with fully personalized, abutment-free monolithic CAD-CAM zirconia crowns exhibited similar failure loads as conventional implant-abutment interfaces (except group Ti-Base-2) involving CAD-CAM crowns with prefabricated or centrally manufactured abutment. CLINICAL SIGNIFICANCE The new implant connection simplifies the digital workflow for all-ceramic implant reconstructions. The specific design of the implant-crown interface allows the fabrication of fully personalized, abutment-free zirconia implant crowns both in-house and in-laboratory without the need of a prefabricated abutment or central manufacturing.
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Affiliation(s)
- Jenni Hjerppe
- Clinic of Reconstructive Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, CH-8032 Zurich, Switzerland.
| | - Ronald E Jung
- Clinic of Reconstructive Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, CH-8032 Zurich, Switzerland
| | - Christoph Hf Hämmerle
- Clinic of Reconstructive Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, CH-8032 Zurich, Switzerland
| | - Mutlu Özcan
- Clinic of Reconstructive Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, CH-8032 Zurich, Switzerland
| | - Sven Mühlemann
- Clinic of Reconstructive Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, CH-8032 Zurich, Switzerland
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Prabahar T, Gupta N, Chowdhary N, Sonnahalli NK, Chowdhary R, Reddy VR. Comparative Evaluation of Occlusal Bite Force in Relation to the Muscle Activity in the Mixed Dentition Children of Age Group 9-12 Years: A T-scan Analysis. Int J Clin Pediatr Dent 2022; 14:S29-S34. [PMID: 35082463 PMCID: PMC8754266 DOI: 10.5005/jp-journals-10005-2019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Aim and objective Compare and evaluate the muscle activity and the occlusal force between the mixed dentition boys and girls of 9-12 years. Materials and methods The study included 15 boys and 15 girls. The occlusal force and activity of the masseter and temporalis muscle were measured with a T-scan device using a sensor, a module to transmit the signals to a computer and the complete data of the bite force and muscle activity with the EMG recordings and data were collected and evaluated. Results Relative occlusal force in the primary and permanent molars between the boys and girls showed no significant difference on the left side compared to the right. The electromyography values of masseter and temporalis in boys and girls showed a significant difference in which (TAR and MMR), (TAR and MML), (TAL and MMR), and (TAL and MML) are significant. The overall paired sample statistics showed higher muscle activity in masseter. Conclusion T-scan analysis has proved to be a dependable method for the evaluation of occlusal bite force with the muscle activity interpretation using EMG. This study concluded that there is a difference in the occlusal pattern and muscle activity in the mixed dentition that showed the maximum force was on the permanent molars and the symmetry of EMGs activity in children was on the right masseter comparatively with higher bite values in boys compared to girls. Clinical significance T-scan is a computerized analysis system that helps in the proper assessment of the patient's occlusion and assists in the proper treatment planning and diagnosis accurately without much effort. How to cite this article Prabahar T, Gupta N, Chowdhary NR, et al. Comparative Evaluation of Occlusal Bite Force in Relation to the Muscle Activity in the Mixed Dentition Children of Age Group 9-12 Years: A T-scan Analysis. Int J Clin Pediatr Dent 2021;14(S-1):S29-S34.
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Affiliation(s)
- Tanuja Prabahar
- Department of Pedodontics and Preventive Dentistry, Sri Siddhartha Dental college and Hospital, Sri Siddhartha Academy of Higher Education, Tumakuru, Karnataka, India
| | - Nisha Gupta
- Department of Pedodontics and Preventive Dentistry, Sri Siddhartha Dental college and Hospital, Sri Siddhartha Academy of Higher Education, Tumakuru, Karnataka, India
| | - Nagalakshmi Chowdhary
- Department of Pedodontics and Preventive Dentistry, Sri Siddhartha Dental college and Hospital, Sri Siddhartha Academy of Higher Education, Tumakuru, Karnataka, India
| | - Nithin Kumar Sonnahalli
- Department of Prosthodontics, Sri Siddhartha Dental college and Hospital, Sri Siddhartha Academy of Higher Education, Tumakuru, Karnataka, India
| | - Ramesh Chowdhary
- Brånemark Osseointegration Center India, Vijaynagar, Bengaluru, Karnataka, India
| | - Vundela Rajashekar Reddy
- Department of Pedodontics and Preventive Dentistry, Sri Siddhartha Dental college and Hospital, Sri Siddhartha Academy of Higher Education, Tumakuru, Karnataka, India
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Szyszka-Sommerfeld L, Sycińska-Dziarnowska M, Machoy M, Wilczyński S, Maglitto M, Cernera M, Spagnuolo G, Woźniak K. Electromyographic Study of Masticatory Muscle Function in Children with Down Syndrome. J Clin Med 2022; 11:jcm11030506. [PMID: 35159958 PMCID: PMC8837010 DOI: 10.3390/jcm11030506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 01/16/2022] [Accepted: 01/18/2022] [Indexed: 11/16/2022] Open
Abstract
This study assessed the electrical activity of the masticatory muscles in both children with down syndrome (DS) and healthy children. After applying the inclusion and exclusion criteria, 30 patients aged between 7.9 and 11.8 years participated in the study. They were divided into two groups of 15: DS and non-DS. A DAB-Bluetooth device (Zebris Medical GmbH, Germany) was used to record the electromyographical (EMG) activity of the right and left temporal and of the right and left masseter muscles at rest and during maximum voluntary clenching (MVC). The asymmetry index between right and left masticatory muscle EMG activity was calculated for each position. The Mann–Whitney U test was applied to analyze the study results. There were no differences in the electrical activity of the temporal and masseter muscles at rest between the groups. During MVC, the asymmetry index for the masseter muscles was significantly higher in subjects with DS. The electrical potentials of the temporal and masseter muscles in children with DS were significantly lower compared to the corresponding parameters for healthy children when clenching.
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Affiliation(s)
- Liliana Szyszka-Sommerfeld
- Department of Orthodontics, Pomeranian Medical University in Szczecin, Al. Powst. Wlkp. 72, 70111 Szczecin, Poland; (L.S.-S.); (M.S.-D.); (M.M.); (K.W.)
| | - Magdalena Sycińska-Dziarnowska
- Department of Orthodontics, Pomeranian Medical University in Szczecin, Al. Powst. Wlkp. 72, 70111 Szczecin, Poland; (L.S.-S.); (M.S.-D.); (M.M.); (K.W.)
| | - Monika Machoy
- Department of Orthodontics, Pomeranian Medical University in Szczecin, Al. Powst. Wlkp. 72, 70111 Szczecin, Poland; (L.S.-S.); (M.S.-D.); (M.M.); (K.W.)
| | - Sławomir Wilczyński
- Department of Basic Biomedical Science, Medical University of Silesia in Katowice, 3 Kasztanowa Street, 41200 Sosnowiec, Poland;
| | - Marzia Maglitto
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples Federico II, 80131 Naples, Italy; (M.M.); (M.C.)
| | - Mariangela Cernera
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples Federico II, 80131 Naples, Italy; (M.M.); (M.C.)
| | - Gianrico Spagnuolo
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples Federico II, 80131 Naples, Italy; (M.M.); (M.C.)
- Institute of Dentistry, I. M. Sechenov First Moscow State Medical University, 119435 Moscow, Russia
- Correspondence:
| | - Krzysztof Woźniak
- Department of Orthodontics, Pomeranian Medical University in Szczecin, Al. Powst. Wlkp. 72, 70111 Szczecin, Poland; (L.S.-S.); (M.S.-D.); (M.M.); (K.W.)
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Haroyan-Darbinyan E, Romeo-Rubio M, Río-Highsmith JD, Lynch CD, Castillo-Oyagüe R. Fracture resistance of cantilevered full-arch implant-supported hybrid prostheses with carbon fiber frameworks after thermal cycling. J Dent 2021; 116:103902. [PMID: 34822914 DOI: 10.1016/j.jdent.2021.103902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES This in vitro study aimed to find the best combination of mesostructure and veneering materials for full-arch implant-supported hybrid prostheses (HPs) in terms of the fracture resistance (FR) of their cantilevers. METHODS Three groups (n = 5 each) of maxillary HPs were fabricated: Group-1 (CC-A, control): Co-Cr frameworks coated with acrylic resin; Group-2 (CF-A): carbon fiber veneered with acrylic resin; and Group-3 (CF-R): carbon fiber coated with composite resin. All specimens were submitted to 5,000 thermal cycles (5 °C - 55 °C, dwell time: 30 s), and subjected to a single cantilever bending test in a universal testing machine (crosshead speed: 0.5 mm/min) until failure. The fracture pattern was assessed using stereo microscope and SEM. The one-way ANOVA and Bonferroni tests were run (α= 0.05). RESULTS The FR yielded significant differences among the three groups (p< 0.001). CC-A samples reached the highest FR values (p ≤ 0.001), whereas both CF-A and CF-R HPs exhibited the comparably (p = 0.107) lowest FR. CC-A specimens failed cohesively (100%): mostly without chipping (80%). CF-A mesostructures were always broken at the connections of the distal implants. CF-R prostheses often failed adhesively (80%). CONCLUSIONS The HPs made of Co-Cr veneered with acrylic demonstrated the best mechanical behavior, being the only group whose 13-mm long cantilevers exceeded the clinically acceptable FR of 900 N. The HPs constructed with carbon fiber frameworks showed, additionally, more unfavorable fracture patterns. CLINICAL SIGNIFICANCE For HPs with cantilevers up to 13 mm, Co-Cr mesostructures coated with acrylic may represent the optimum combination of materials.
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Affiliation(s)
| | - Marta Romeo-Rubio
- Faculty of Dentistry, Complutense University of Madrid (U.C.M.), Madrid, Spain.
| | | | - Christopher D Lynch
- University Dental School & Hospital/University College Cork, Wilton, Cork, Ireland.
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Prott LS, Spitznagel FA, Bonfante EA, Malassa MA, Gierthmuehlen PC. Monolithic zirconia crowns: effect of thickness reduction on fatigue behavior and failure load. J Adv Prosthodont 2021; 13:269-280. [PMID: 34777717 PMCID: PMC8558575 DOI: 10.4047/jap.2021.13.5.269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 08/30/2021] [Accepted: 09/14/2021] [Indexed: 11/23/2022] Open
Abstract
PURPOSE The objective of this study was to evaluate the effect of thickness reduction and fatigue on the failure load of monolithic zirconia crowns. MATERIALS AND METHODS 140 CAD-CAM fabricated crowns (3Y-TZP, inCorisTZI, Dentsply-Sirona) with different ceramic thicknesses (2.0, 1.5, 1.0, 0.8, 0.5 mm, respectively, named G2, G1.5, G1, G0.8, and G0.5) were investigated. Dies of a mandibular first molar were made of composite resin. The zirconia crowns were luted with a resin composite cement (RelyX Unicem 2 Automix, 3M ESPE). Half of the specimens (n = 14 per group) were mouth-motion-fatigued (1.2 million cycles, 1.6 Hz, 200 N/ 5 – 55℃, groups named G2-F, G1.5-F, G1-F, G0.8-F, and G0.5-F). Single-load to failure was performed using a universal testing-machine. Fracture modes were analyzed. Data were statistically analyzed using a Weibull 2-parameter distribution (90% CI) to determine the characteristic strength and Weibull modulus differences among the groups. RESULTS Three crowns (21%) of G0.8 and five crowns (36%) of G0.5 showed cracks after fatigue. Characteristic strength was the highest for G2, followed by G1.5. Intermediate values were observed for G1 and G1-F, followed by significantly lower values for G0.8, G0.8-F, and G0.5, and the lowest for G0.5-F. Weibull modulus was the lowest for G0.8, intermediate for G0.8-F and G0.5, and significantly higher for the remaining groups. Fatigue only affected G0.5-F. CONCLUSION Reduced crown thickness lead to reduced characteristic strength, even under failure loads that exceed physiological chewing forces. Fatigue significantly reduced the failure load of 0.5 mm monolithic 3Y-TZP crowns.
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Affiliation(s)
- Lea Sophia Prott
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
| | - Frank Akito Spitznagel
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
| | - Estevam Augusto Bonfante
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of Sao Paulo, Bauru, SP, Brazil
| | | | - Petra Christine Gierthmuehlen
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
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Sadeqi HA, Baig MR, Al-Shammari M. Evaluation of Marginal/Internal Fit and Fracture Load of Monolithic Zirconia and Zirconia Lithium Silicate (ZLS) CAD/CAM Crown Systems. MATERIALS 2021; 14:ma14216346. [PMID: 34771872 PMCID: PMC8585271 DOI: 10.3390/ma14216346] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/15/2021] [Accepted: 10/20/2021] [Indexed: 11/24/2022]
Abstract
Fit accuracy and fracture strength of milled monolithic zirconia (Zi) and zirconia-reinforced lithium silicate (ZLS) crowns are important parameters determining the success of these restorations. This study aimed to evaluate and compare the marginal and internal fit of monolithic Zi and ZLS crowns, along with the fracture load, with and without mechanical aging. Thirty-two stone dies acquired from a customized master metal molar die were scanned, and ceramic crowns (16 Zi Ceramill Zolid HT+ and 16 ZLS Vita Suprinity) were designed and milled. Absolute marginal discrepancies (AMD), marginal gaps (MG), and internal gaps (IG) of the crowns, in relation to the master metal die, were evaluated using x-ray nanotomography (n = 16). Next, thirty-two metal dies were fabricated based on the master metal die, and crowns (16 Zi; 16 ZLS) cemented and divided into four groups of eight each; eight Zi with mechanical aging (MA), eight Zi without mechanical aging (WMA), eight ZLS (MA), and eight ZLS (WMA). Two groups of crowns (Zi-MA; ZLS-MA) were subjected to 500,000 mechanical cycles (200 ± 50 N, 10 Hz) followed by axial compressive strength testing of all crowns, until failure, and the values were recorded. Independent sample t tests (α = 0.05) revealed no significant differences between Zi and ZLS crowns (p > 0.05); for both internal and marginal gaps, however, there were significant differences in AMD (p < 0.005). Independent samples Mann–Whitney U and Kruskal–Wallis tests revealed significant differences between the two materials, Zi and ZLS, regardless of fatigue loading, and for the individual material groups based on aging (α = 0.05). Multiple comparisons using Bonferroni post-hoc analysis showed significant differences between Zi and ZLS material groups, with or without aging. Within the limitations of this study, the ZLS crown fit was found to be on par with Zi, except for the AMD parameter. As regards fracture resistance, both materials survived the normal range of masticatory forces, but the Zi crowns demonstrated greater resistance to fracture. The monolithic Zi and ZLS crowns seem suitable for clinical application, based on the fit and fracture strength values obtained.
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Affiliation(s)
- Haneen A. Sadeqi
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, P.O. Box 24923,
Safat 13110, Kuwait; (H.A.S.); (M.A.-S.)
| | - Mirza Rustum Baig
- Department of Restorative Sciences (Prosthodontics), Faculty of Dentistry, Kuwait University, P.O. Box 24923,
Safat 13110, Kuwait
- Correspondence:
| | - Mohammad Al-Shammari
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, P.O. Box 24923,
Safat 13110, Kuwait; (H.A.S.); (M.A.-S.)
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Moreira A, Batista R, Oliveira S, Mendes J, Sampaio-Fernandes M, Figueiral MH. The Thermal Influence of Oral Rehabilitation on the Cranio-Cervico-Mandibular Complex: A Thermographic Analysis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph181910441. [PMID: 34639742 PMCID: PMC8508334 DOI: 10.3390/ijerph181910441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 09/24/2021] [Accepted: 09/29/2021] [Indexed: 11/16/2022]
Abstract
PURPOSE Assess the thermal effect of prosthodontic treatment on the cranio-cervico-mandibular complex using infrared thermography. METHODS The treatment group was composed of adults of both sexes who underwent a prosthodontic treatment in which at least posterior occlusal contacts were added and/or the vertical dimension of occlusion was reestablished. The control group (CG) was constituted of adult subjects of both sexes, with no more than a single missing posterior tooth, excluding third molars. Thermograms were taken of the treatment group with a Flir i7 IR camera both before oral rehabilitation (TGB; n = 33) and two months after treatment was concluded (TGA; n = 19). CG (n = 33) had only one occasion for data acquisition. RESULTS Statistically significant differences were found when the thermal difference (ΔT) and the health status of the orbicularis oris muscle were compared between the TGB and the TGA groups (p = 0.020 and p = 0.003, respectively). By comparing the health status of the masseter muscle between the CG and TGB, statistically significant differences were also observed (p = 0.030). CONCLUSION A prosthodontic treatment appears to have a minimum or null effect on the ΔT and/or on the health status of the TMJ and the temporal muscle. In contrast, orbicularis oris muscles exhibited significant thermal variations.
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Affiliation(s)
- André Moreira
- Department of Prosthodontics, Faculty of Dental Medicine, University of Porto, 4200-393 Porto, Portugal; (R.B.); (S.O.); (M.S.-F.)
- Correspondence:
| | - Ricardo Batista
- Department of Prosthodontics, Faculty of Dental Medicine, University of Porto, 4200-393 Porto, Portugal; (R.B.); (S.O.); (M.S.-F.)
| | - Susana Oliveira
- Department of Prosthodontics, Faculty of Dental Medicine, University of Porto, 4200-393 Porto, Portugal; (R.B.); (S.O.); (M.S.-F.)
| | - Joaquim Mendes
- INEGI, Department of Mechanics, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal;
| | - Margarida Sampaio-Fernandes
- Department of Prosthodontics, Faculty of Dental Medicine, University of Porto, 4200-393 Porto, Portugal; (R.B.); (S.O.); (M.S.-F.)
| | - Maria Helena Figueiral
- INEGI, Department of Prosthodontics, Faculty of Dental Medicine, University of Porto, 4200-393 Porto, Portugal;
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A Redundantly Actuated Chewing Robot Based on Human Musculoskeletal Biomechanics: Differential Kinematics, Stiffness Analysis, Driving Force Optimization and Experiment. MACHINES 2021. [DOI: 10.3390/machines9080171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Human masticatory system exhibits optimal stiffness, energy efficiency and chewing forces needed for the food breakdown due to its unique musculoskeletal actuation redundancy. We have proposed a 6PUS-2HKP (6 prismatic-universal-spherical chains, 2 higher kinematic pairs) redundantly actuated parallel robot (RAPR) based on its musculoskeletal biomechanics. This paper studies the stiffness and optimization of driving force of the bio-inspired redundantly actuated chewing robot. To understand the effect of the point-contact HKP acting on the RAPR performance, the stiffness of the RAPR is estimated based on the derived dimensionally homogeneous Jacobian matrix. In analyzing the influence of the HKP on robot dynamics, the driving forces of six prismatic joints are optimized by adopting the pseudo-inverse optimization method. Numerical results show that the 6PUS-2HKP RAPR has better stiffness performance and more homogenous driving power than its non-redundant 6-PUS counterpart, verifying the benefits that the point-contact HKP brings to the RAPR. Experiments are carried out to measure the temporomandibular joint (TMJ) force and the occlusal force that the robot can generate. The relationship between these two forces in a typical chewing movement is studied. The simulation and experimental results reveal that the existence of TMJs in human masticatory system can provide more homogenous and more efficient chewing force transmission.
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Comparative Evaluation of Occlusion before and after Soft Tissue Mobilization in Patients with Temporomandibular Disorder-Myofascial Pain with Referral. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18126568. [PMID: 34207403 PMCID: PMC8296451 DOI: 10.3390/ijerph18126568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/13/2021] [Accepted: 06/15/2021] [Indexed: 02/06/2023]
Abstract
The aim of the study was to evaluate occlusal parameters in patients with myofascial pain with referral before and after soft tissue mobilization. The study group consisted of 50 people (37 females and 13 males, average age 23.36 ± 2.14 years) diagnosed with myofascial pain with referral. All patients underwent triplicate soft tissue mobilization. Occlusal parameters were evaluated six times, before and after each treatment, using T-scan III. A decreasing tendency of the occlusion time was observed after the first, second, and third therapy. After the third treatment, the mean occlusion time in the entire study group was 0.119 s. The 1st soft tissue mobilization shortened both right and left disclusion times to 0.181 s and 0.185 s, respectively. After the third treatment, these parameters amounted to 0.159 s and 0.165 s, respectively. The Friedman test for the entire study group indicated that soft tissue mobilization altered the occlusion time and both disclusion times (p < 0.05). In conclusion, soft tissue mobilization affects biotensegrity of the masticatory system, thus modifying occlusal parameters. The occlusion time and both disclusion times cannot be considered as cofactors of the existing temporomandibular disorders-myofascial pain with referral.
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Alsharif HNH, Ganji KK, Alam MK, Manay SM, Bandela V, Sghaireen MG, Mousa MA. Periodontal Clinical Parameters as a Predictor of Bite Force: A Cross-Sectional Study. BIOMED RESEARCH INTERNATIONAL 2021; 2021:5582946. [PMID: 34046498 PMCID: PMC8128538 DOI: 10.1155/2021/5582946] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/22/2021] [Accepted: 04/27/2021] [Indexed: 12/29/2022]
Abstract
OBJECTIVE To investigate the correlation of periodontal parameters and bite force in different stages of periodontitis after phase I periodontal therapy. METHODS Periodontal clinical parameters such as mobility, attachment loss, gingival recession, and percentage of bone remaining were recorded at the mandibular first molar region after phase I therapy in subjects categorized according to the stage of periodontitis. Corresponding bite force was recorded at the first mandibular molar region using a bite force device after phase I therapy. ANOVA test was used to assess the significant difference among different groups. Pearson correlation coefficient was used to assess the correlation between measured variables. RESULTS The ANOVA test represents that there is no statistical significant difference between the bite force in stage I, stage II, and stage III type of periodontitis. A strong positive correlation was found (r = 0.537) between bite force and percentage of remaining alveolar bone support whereas negative correlation was observed in measured parameters such as mobility (r = -0.0181), attachment loss (r = -0.608), and gingival recession (r = -0.435). CONCLUSION Among all periodontal clinical parameters, the percentage of remaining alveolar bone is the strong predictor of bite force and mobility; attachment loss and gingival recession cannot predict the bite force in the first molar region. Bite force is variable in different stages of periodontitis.
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Affiliation(s)
| | - Kiran Kumar Ganji
- Department of Preventive Dentistry, College of Dentistry, Jouf University, Sakaka, Saudi Arabia
| | - Mohammad Khursheed Alam
- Department of Preventive Dentistry, College of Dentistry, Jouf University, Sakaka, Saudi Arabia
| | | | - Vinod Bandela
- Department of Prosthetic Dental Sciences, College of Dentistry, Jouf University, Sakaka, Saudi Arabia
| | - Mohammed Ghazi Sghaireen
- Department of Prosthetic Dental Sciences, College of Dentistry, Jouf University, Sakaka, Saudi Arabia
| | - Mohammed Assayed Mousa
- Department of Prosthetic Dental Sciences, College of Dentistry, Jouf University, Sakaka, Saudi Arabia
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Park CJ, Son JJ, Lin R, Phark JH, Wilson ML, Chee WW, Cho G. Evaluation of fracture resistance of zirconia modification/polishing around implant abutments. J ORAL IMPLANTOL 2021; 48:202-209. [PMID: 33945621 DOI: 10.1563/aaid-joi-d-20-00144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Subcrestal placement of implants may have interproximal bone proximity issues that interfere with submucosal contour of the implant-supported Zirconia restorations during delivery of these restorations. Modification of the mesial distal submucosal areas may be necessary to fully seat the restoration without impingement of the interproximal bone. Our aim was to determine if modification of submucosal cervical contour of implant supported zirconia titanium base (Zi-Ti base) restorations result in a significant change in fracture strength compared to Zi-Ti base restorations without any modification near the cervical submucosal area. Implant Zi-Ti base restorations, designed in the form of a maxillary premolar was made for the Straumann implant lab analog. Zirconia samples were cemented onto the Ti-base and the test group (N=20) underwent recontouring and polishing at the junction of the Zi-Ti-base cervical areas. The control group (N=20) did not undergo any modifications. All 40 samples underwent fracture testing with an Instron machine. We assessed differences between modified and unmodified implant restorations using a two-tailed t-test for independent samples. Fracture strength values (N) ranged from 4,354.68 to 6,412.49 in the test group (N=20) and from 5,400.31 to 6,953.22 in the control group (N=20). The average fracture strength in the control group (6,154.84 ± 320.50) was higher than in the modified group (5,593.13 ± 486.51; p<.001)). Modification of submucosal contour significantly decreased the fracture strength. However, the average fracture strength exceeded the masticatory forces of humans.
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Affiliation(s)
- Cheryl Jonghee Park
- Herman Ostrow School of Dentistry of University of Southern California Dentistry 925 W. 34th Street Rm4374 UNITED STATES Los Angeles CA 90089 12139991716 Assistant Professor of Clinical Dentistry, Carl Rieder Professor of Restorative Dentistry, Division of Restorative Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, USA
| | - Jenny Jin Son
- Assistant Professor of Clinical Dentistry, Division of Restorative Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, USA
| | - Richard Lin
- Assistant Professor of Clinical Dentistry, Director of CAD/CAM Dentistry, Division of Restorative Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, USA
| | - Jin-Ho Phark
- Associate Professor of Clinical Dentistry, Director of Biomaterials Research Laboratory, Co-Director of Advanced Program in Operative and Adhesive Dentistry, Division of Restorative Sciences, Herman Ostrow School of Dentistry, University of Southern Califo
| | - Melissa Lee Wilson
- Associate Professor of Clinical Preventive Medicine, University of Southern California KECK School of Medicine, Los Angeles, California, USA
| | - Winston W Chee
- Associate Professor, Ralph & Jean Bleak Professor of Restorative Dentistry, Director of Advanced Education in Prosthodontics, Director of Implant Dentistry, Herman Ostrow School of Dentistry of University of Southern California, Los Angeles, California, US
| | - George Cho
- Associate Professor, Phillip Maurer Tennis Professor of Clinical Dentistry, Assistant Director of Advanced Prosthodontics, Director of Predoctoral Implant Dentistry, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, Califor
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Burkhardt F, Harlass M, Adolfsson E, Vach K, Spies BC, Kohal RJ. A Novel Zirconia-Based Composite Presents an Aging Resistant Material for Narrow-Diameter Ceramic Implants. MATERIALS 2021; 14:ma14092151. [PMID: 33922688 PMCID: PMC8122934 DOI: 10.3390/ma14092151] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 01/23/2023]
Abstract
A novel ceria-stabilized zirconia-alumina-aluminate composite (Ce-TZP-comp) that is not prone to aging presents a potential alternative to yttrium-stabilized zirconia for ceramic oral implants. The objective of this study was to evaluate the long-term stability of a one-piece narrow-diameter implant made of Ce-TZP-comp. Implant prototypes with a narrow (3.4 mm) and regular (4.0 mm) diameter were embedded according to ISO 14801, and subgroups (n = 8) were subsequently exposed to dynamic loading (107 cycles, 98N) and/or hydrothermal treatment (aging, 85 °C). Loading/aging was only applied as a combined protocol for the 4.0 mm diameter implants. One subgroup of each diameter remained untreated. One sample was cross-sectioned from each subgroup and evaluated with a scanning electron microscope for phase-transformation of the lattice. Finally, the remaining samples were loaded to fracture. A multivariate linear regression model was applied for statistical analyses (significance at p < 0.05). All samples withstood the different loading/aging protocols and no transformation propagation was observed. The narrow diameter implants showed the lowest fracture load after combined loading/aging (628 ± 56 N; p < 0.01), whereas all other subgroups exhibited no significantly reduced fracture resistance (between 762 ± 62 and 806 ± 73 N; p > 0.05). Therefore, fracture load values of Ce-TZP-comp implants suggest a reliable intraoral clinical application in the anterior jaw regions.
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Affiliation(s)
- Felix Burkhardt
- Medical Center—University of Freiburg, Center for Dental Medicine, Department of Prosthetic Dentistry, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany; (F.B.); (M.H.); (B.C.S.)
| | - Markus Harlass
- Medical Center—University of Freiburg, Center for Dental Medicine, Department of Prosthetic Dentistry, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany; (F.B.); (M.H.); (B.C.S.)
| | | | - Kirstin Vach
- Medical Center—University of Freiburg, Institute for Medical Biometry and Statistics, Faculty of Medicine, University of Freiburg, Stefan-Meier-Str. 26, 79104 Freiburg, Germany;
| | - Benedikt Christopher Spies
- Medical Center—University of Freiburg, Center for Dental Medicine, Department of Prosthetic Dentistry, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany; (F.B.); (M.H.); (B.C.S.)
| | - Ralf-Joachim Kohal
- Medical Center—University of Freiburg, Center for Dental Medicine, Department of Prosthetic Dentistry, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany; (F.B.); (M.H.); (B.C.S.)
- Correspondence:
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Yilmaz B, Gouveia D, Seghi R, Johnston W, Lang LA. Effect of crown height on the screw joint stability of zirconia screw-retained crowns. J Prosthet Dent 2021; 128:1328-1334. [PMID: 33838917 DOI: 10.1016/j.prosdent.2021.02.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 02/12/2021] [Accepted: 02/12/2021] [Indexed: 10/21/2022]
Abstract
STATEMENT OF PROBLEM Medium- to long-term data for the performance of zirconia crowns with titanium (Ti) bases are sparse, particularly when the crown height space and occlusal loads are high. PURPOSE The purpose of this in vitro study was to assess the effect of the height of zirconia screw-retained implant crowns with a Ti base on the screw joint stability after cyclic loading. A secondary aim was to investigate the survival of zirconia crowns of different heights after cyclic loading. MATERIAL AND METHODS Twenty-one internal connection implants were secured between fiberglass-reinforced epoxy resin sleeves. Mandibular first molar monolithic zirconia crowns with 3 different heights (6 mm, 10 mm, and 14 mm) were milled and bonded to the Ti bases (n=7). The screws were tightened to 30 Ncm, and a 30-degree 120-N cyclic load was applied to the crowns at 2 Hz for 5 million cycles. After 5 million cycles, the crowns were evaluated for stability, and the same protocol was repeated for 275-N and 435-N loads for 5 million cycles each. After loading, the detorque values were recorded. Failure was characterized based on whether the crown, screw, and/or implant fracture was observed. The detorque values were analyzed by using a 1-way-ANOVA with the restricted maximum likelihood estimation. The percentage of torque loss was calculated. The LIFETEST procedure was used to analyze the survival probability of the groups (α=.05). RESULTS The effect of crown height on the detorque values of screws was not found to be statistically significant (P>.05). The mean detorque value for 6-mm crowns was 23.5 Ncm, 24.4 Ncm for 10-mm crowns, and 22.1 Ncm for 14-mm crowns. A significant effect of crown height was found on the survival (P=.006), and the time-to-failure survival of 14-mm crowns was significantly lower than the survival of 6 mm and 10 mm crowns (P=.020), where no failures were observed. Four 14-mm crowns failed between the 1 and 2 million cycles after the loads were increased to 435 N. The failure modes were the same for all the crowns, implants, and screws fractured. CONCLUSIONS When the tested internal connection implant was used, the crown height did not affect the detorque values, and 14-mm crowns performed similarly to the shorter crowns in terms of torque loss after cyclic loading. However, survival of the 14-mm crown-implant complex was lower, resulting in screw and implant fractures.
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Affiliation(s)
- Burak Yilmaz
- Professor, Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, Ohio
| | - Diogo Gouveia
- Assistant Professor, Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, Ohio.
| | - Robert Seghi
- Professor Emeritus, Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, Ohio
| | - William Johnston
- Professor Emeritus, Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, Ohio
| | - Lisa A Lang
- Professor, Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, Ohio
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Fathy SM, Al-Zordk W, E Grawish M, V Swain M. Flexural strength and translucency characterization of aesthetic monolithic zirconia and relevance to clinical indications: A systematic review. Dent Mater 2021; 37:711-730. [PMID: 33581910 DOI: 10.1016/j.dental.2021.01.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/15/2020] [Accepted: 01/20/2021] [Indexed: 02/04/2023]
Affiliation(s)
- Salma M Fathy
- Dental Biomaterials Department, Faculty of Oral and Dental Medicine, Zagazig University, Zagazig, Egypt.
| | - Walid Al-Zordk
- Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt
| | - Mohammed E Grawish
- Oral Biology Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt
| | - Micheal V Swain
- Discipline of Biomaterials, Faculty of Dentistry, University of Sydney, Australia
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Martín-Ortega N, Sallorenzo A, Casajús J, Cervera A, Revilla-León M, Gómez-Polo M. Fracture resistance of additive manufactured and milled implant-supported interim crowns. J Prosthet Dent 2021; 127:267-274. [PMID: 33431173 DOI: 10.1016/j.prosdent.2020.11.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 12/20/2022]
Abstract
STATEMENT OF PROBLEM Interim dental prostheses can be fabricated by using subtractive or additive manufacturing technologies. However, the fracture resistance of implant-supported interim crowns fabricated by using vat-polymerization additive manufacturing methods remains unclear. PURPOSE The purpose of this in vitro study was to evaluate the fracture resistance of anterior and posterior screw-retained implant-supported interim crowns fabricated by using subtractive and vat-polymerization direct light processing (DLP) additive manufacturing procedures. MATERIAL AND METHODS An implant (Zinic Implant RP ∅4.0×10 mm) was placed in a 15×15-mm polymethylmethacrylate block. An implant abutment (ZiaCam, nonrotatory RP) was positioned on each implant. The virtual implant abutment standard tessellation language (STL) file provided by the manufacturer was imported into a software program (Exocad v2.2 Valletta) to design 2 anatomic contour crowns, a maxillary right central incisor (anterior group) and a maxillary right premolar (posterior group). Each group was subdivided into 2 subgroups depending on the manufacturing method: milled (milled subgroup) and additive manufacturing (additive manufacturing subgroup). For the milled subgroup, an interim material (Vivodent CAD Multi) and a milling machine were used to fabricate all the specimens (N=40, n=10). For the additive manufacturing subgroup, a polymer interim material (SHERAprint-cb) and a DLP printer (SHERAprint 30) were used to manufacture all the specimens at a 50-μm layer thickness and 45-degree build orientation as per the manufacturer's instructions. Then, each specimen was cemented to an implant abutment by using composite resin cement (Multilink Hybrid Abutment HO) as per the manufacturer's instructions. A universal testing machine was used for fracture resistance analysis, and the failure mode was recorded. The Shapiro-Wilk test revealed that data were normally distributed. One-way ANOVA and Tukey multiple comparison were selected (α=.05). RESULTS One-way ANOVA revealed significant differences among the groups (P<.05). The anterior milled subgroup obtained a significantly higher fracture resistance mean ±standard deviation value of 988.4 ±54.8 N compared with the anterior additive manufacturing subgroup of 636.5 ±277.1 N (P<.001), and the posterior milled subgroup obtained significantly higher mean ±standard deviation of 423.8 ±68 N than the additive manufacturing subgroup of 321.3 ±128.6 N (P=.048). All groups presented crown fracture without abutment fracture. CONCLUSIONS Manufacturing procedures and tooth type influenced the fracture resistance of screw-retained implant-supported interim crowns. Milled specimens obtained higher fracture resistance compared with the DLP additive manufacturing groups. The anterior group was higher than the posterior group.
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Affiliation(s)
- Nuria Martín-Ortega
- Graduate student, Advanced in Implant Prosthodontics, Department of Conservative Dentistry and Prosthodontics, School of Dentistry, Complutense University of Madrid, Madrid, Spain
| | - Alessandro Sallorenzo
- Graduate student, Advanced in Implant Prosthodontics, Department of Conservative Dentistry and Prosthodontics, School of Dentistry, Complutense University of Madrid, Madrid, Spain
| | - Javier Casajús
- Assistant Professor of Signal Processing Applications Group, Department of Signals, Systems, and Telecommunications, Politécnica University of Madrid, Madrid, Spain
| | - Alberto Cervera
- Guest Lecturer, Materials Engineering Department, Carlos III University of Madrid, Madrid, Spain
| | - Marta Revilla-León
- Assistant Professor and Assistant Program Director, AEGD Residency, Department of Comprehensive Dentistry, College of Dentistry, Texas A&M University, Dallas, Texas; Affiliate Faculty Graduate Prosthodontics, Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, Wash; Researcher at Revilla Research Center, Madrid, Spain.
| | - Miguel Gómez-Polo
- Associate Professor and Program Director of Graduate in Advanced Implant Prosthodontics, Department of Conservative Dentistry and Prosthodontics, School of Dentistry, Complutense University of Madrid, Madrid, Spain
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Woodford SC, Robinson DL, Edelmann C, Mehl A, Röhrle O, Vee Sin Lee P, Ackland DC. Low-Profile Electromagnetic Field Sensors in the Measurement and Modelling of Three-Dimensional Jaw Kinematics and Occlusal Loading. Ann Biomed Eng 2021; 49:1561-1571. [PMID: 33409850 DOI: 10.1007/s10439-020-02688-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 11/04/2020] [Indexed: 11/30/2022]
Abstract
Dynamic occlusal loading during mastication is clinically relevant in the design and functional assessment of dental restorations and removable dentures, and in evaluating temporomandibular joint dysfunction. The aim of this study was to develop a modelling framework to evaluate subject-specific dynamic occlusal loading during chewing and biting over the entire dental arch. Measurements of jaw motion were performed on one healthy male adult using low-profile electromagnetic field sensors attached to the teeth, and occlusal anatomy quantified using an intra-oral scanner. During testing, the subject chewed and maximally compressed a piece of rubber between both second molars, first molars, premolars and their central incisors. The occlusal anatomy, rubber geometry and experimentally measured rubber material properties were combined in a finite element model. The measured mandibular motion was used to kinematically drive model simulations of chewing and biting of the rubber sample. Three-dimensional dynamic bite forces and contact pressures across the occlusal surfaces were then calculated. Both chewing and biting on the first molars produced the highest bite forces across the dental arch, and a large amount of anterior shear force was produced at the incisors and the second molars. During chewing, the initial tooth-rubber contact evolved from the buccal sides of the molars to the lingual sides at full mouth closure. Low-profile electromagnetic field sensors were shown to provide a clinically relevant measure of jaw kinematics with sufficient accuracy to drive finite element models of occlusal loading during chewing and biting. The modelling framework presented provides a basis for calculation of physiological, dynamic occlusal loading across the dental arch.
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Affiliation(s)
- Sarah C Woodford
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Dale L Robinson
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Cornelia Edelmann
- Centre of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Albert Mehl
- Centre of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Oliver Röhrle
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
| | - Peter Vee Sin Lee
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, 3010, Australia
| | - David C Ackland
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, 3010, Australia.
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Lima JMDC, Tribst JPM, Anami LC, de Melo RM, Moura DMD, Souza ROA, Bottino MA. Long-term fracture load of all-ceramic crowns: Effects of veneering ceramic thickness, application techniques, and cooling protocol. J Clin Exp Dent 2020; 12:e1078-e1085. [PMID: 33262875 PMCID: PMC7680567 DOI: 10.4317/jced.57352] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 07/02/2020] [Indexed: 11/14/2022] Open
Abstract
Background To evaluate, in vitro, the effects of the cooling protocol, application technique, and veneering ceramic thickness on the fracture resistance of ceramic crowns with Y-TZP frameworks.
Material and Methods 80 frameworks were made from zirconia by the CAD/CAM technique and divided into 8 groups (n = 10) according to the factors: “application technique” (stratified-L and pressed -P), “thickness” (1 mm and 2 mm), and “cooling protocol” (slow-S and fast-F) of the feldspathic veneering ceramic. After, all crowns were cemented over G10 preparations with resin cement (Panavia F, Kuraray), mechanically cycled (2x106 cycles, 200 N, 3Hz), and subjected to the axial compression resistance test (0.5 mm/min, 10 kN). The data (N) underwent descriptive statistical analysis by 3-way ANOVA and Tukey’s test (5%). Fracture analysis was performed to determine the possible origin of failure.
Results The factors “cooling protocol” (P=0.0058) and “application” technique (P=0.0001) influenced the fracture resistance of the crowns. For pressed veneer technique, the P2S (4608.9±464.5). A presented significantly higher results than that P2F(3621.1±523.0)BCD (Tukey’s test). For the stratified technique, this difference was not observed (P>0.05). The thickness of the veneering ceramic was not significant regardless of the cooling protocol and technique (P>0.05). The predominant failure mode was chipping of the ceramic veneer originating in the subsurface.
Conclusions The pressed technique, used with a slow-cooling protocol, leads to the best outcome for the veneering of all-ceramic crowns. Key words:Zirconia, ceramics, cooling protocol, thickness, application technique.
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Affiliation(s)
| | - João-Paulo-Mendes Tribst
- DDs, MSc, PhD, Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), Institute of Science and Technology, São José dos Campos, São Paulo, Brazil
| | - Lilian-Costa Anami
- DDs, MSc, PhD, Departmentof Dentistry, Santo Amaro University, São Paulo, SP, Brazil
| | - Renata-Marques de Melo
- DDs, MSc, PhD, Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), Institute of Science and Technology, São José dos Campos, São Paulo, Brazil
| | - Dayanne-Monielle-Duarte Moura
- DDs, MSc, PhD, Department of Dentistry, Division of Prosthodontics, Federal University of Rio Grande do Norte (UFRN), Natal/RN, Brazil
| | - Rodrigo-Othávio-Assunção Souza
- DDs, MSc, PhD, Department of Dentistry, Division of Prosthodontics, Federal University of Rio Grande do Norte (UFRN), Natal/RN, Brazil
| | - Marco-Antonio Bottino
- DDs, MSc, PhD, Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), Institute of Science and Technology, São José dos Campos, São Paulo, Brazil
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de Kok P, Kanters GF, Kleverlaan CJ. Fatigue resistance of composite resins and glass-ceramics on dentin and enamel. J Prosthet Dent 2020; 127:593-598. [DOI: 10.1016/j.prosdent.2020.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 11/05/2020] [Accepted: 11/05/2020] [Indexed: 11/16/2022]
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Tekin YH, Hayran Y. Fracture resistance and marginal fit of the zirconia crowns with varied occlusal thickness. J Adv Prosthodont 2020; 12:283-290. [PMID: 33149849 PMCID: PMC7604235 DOI: 10.4047/jap.2020.12.5.283] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/26/2020] [Accepted: 08/13/2020] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The present study aimed to evaluate the clinical applicability of monolithic zirconia (MZ) crowns of different thickness via determination of fracture resistance and marginal fit. MATERIALS AND METHODS MZ crowns with 0.5, 0.8, 1.0, and 1.5 mm thickness and porcelain fused to metal (PFM) crowns were prepared, ten crowns in each group. Marginal gaps of the crowns were measured. All crowns were aged with thermal cycling (5 - 55℃/10000 cycle) and chewing simulator (50 N/1 Hz/lateral movement: 2 mm, mouth opening: 2 mm/240000 cycles). After aging, fracture resistance of crowns was determined. Statistical analysis was performed with one-way ANOVA and Tukey's HDS post hoc test. RESULTS Fracture loads were higher in the PFM and 1 mm MZ crowns compared to 0.5 mm and 0.8 mm crowns. 1.5 mm MZ crowns were not broken even with the highest force applied (10 kN). All marginal gap values were below 86 µm even in the PFM crowns, and PFM crowns had a higher marginal gap than the MZ crowns. CONCLUSION The monolithic zirconia exhibited high fracture resistance and good marginal fit even with the 0.5 mm thickness, which might be used with reduced occlusal thickness and be beneficial in challengingly narrow interocclusal space.
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Affiliation(s)
- Yadel Hazır Tekin
- Department of Prosthodontic Dentistry, Faculty of Dentistry, Tokat Gaziosmanpasa University, Tokat, Turkey
| | - Yeliz Hayran
- Department of Prosthodontic Dentistry, Faculty of Dentistry, Tokat Gaziosmanpasa University, Tokat, Turkey
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Jung BT, Kim WH, Park B, Lee JH, Kim B, Lee JH. Biomechanical evaluation of unilateral subcondylar fracture of the mandible on the varying materials: A finite element analysis. PLoS One 2020; 15:e0240352. [PMID: 33031474 PMCID: PMC7544122 DOI: 10.1371/journal.pone.0240352] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 09/24/2020] [Indexed: 11/19/2022] Open
Abstract
Fixation materials used in the surgical treatment of subcondylar fractures contribute to successful clinical outcomes. In this study, we simulated the mechanical properties of four fixation materials [titanium (Ti), magnesium alloy (Mg alloy), poly-L-lactic acid (PLLA), and hydroxyapatite/poly-L-lactide (HA-PLLA)] in a finite-element analysis model of subcondylar fracture. Two four-hole plates were fixed on the anterior and posterior surfaces of the subcondyle of the mandible. In the simulation model of a subcondylar fracture, we evaluated the stress distribution and mechanical deformation of fixation materials. The stress distribution conspicuously appeared on the condylar neck of the non-fractured side and the center of the anterior plate for all materials. More stress distribution to the biologic component appeared with HA-PLLA than with Ti or Mg alloy, but its effects were less prominent than that of PLLA. The largest deformation was observed with PLLA, followed by HA-PLLA, Mg alloy, and Ti. The results of the present study imply the clinical potential of the HA-PLLA fixation material for open reduction of subcondylar fractures.
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Affiliation(s)
- Bryan Taekyung Jung
- School of Dentistry, University of Detroit Mercy, Detroit, Michigan, United States of America
| | - Won Hyeon Kim
- Department of Mechanical Engineering, Sejong University, Seoul, Korea
- Clinical Translational Research Center for Dental Science, Seoul National University Dental Hospital, Seoul, Korea
| | - Byungho Park
- Department of Oral and Maxillofacial Surgery, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea
| | - Jong-Ho Lee
- Clinical Translational Research Center for Dental Science, Seoul National University Dental Hospital, Seoul, Korea
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Seoul, Korea
| | - Bongju Kim
- Clinical Translational Research Center for Dental Science, Seoul National University Dental Hospital, Seoul, Korea
- * E-mail: (BK); (JHL)
| | - Jee-Ho Lee
- Department of Oral and Maxillofacial Surgery, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea
- * E-mail: (BK); (JHL)
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Alander P, Perea-Lowery L, Vesterinen K, Suominen A, SÄilynoja E, Vallittu PK. Layer structure and load-bearing properties of fibre reinforced composite beam used in cantilever fixed dental prostheses. Dent Mater J 2020; 40:165-172. [PMID: 33028792 DOI: 10.4012/dmj.2019-428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study evaluates the effect of fiber reinforcement quantity and position on fracture load of fixed dental prostheses specimens with different fibre reinforced composite (FRC)/ particulate filler composite (PFC) ratio in a cantilever beam test. Three types of specimen structures where made: Specimens with FRC, PFC, or with a combination of both. Specimen's size was 2.0×2.0×25 mm3 and the thicknesses of the FRC layers were 0, 0.5, 1.0, 1.5 and 2.0 mm. The layers of FRC were placed at the top or at the bottom. Eight groups of specimens were evaluated (n=15/group). The test specimens were statically-loaded until fracture. The fracture loads were linearly dependent on the quantity of the FRC reinforcement when placed at the top (R2=0.941) and bottom (R2=0.896) of the specimens. ANOVA revealed that reinforcement position on the tension side and higher FRC reinforcement volume in the test specimens had positive effect to load bearing capacity (p<0.001).
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Affiliation(s)
- Pasi Alander
- Degree Programme in Dental Technology, Faculty of Health and Well-being, Turku University of Applied Science.,Department of Biomaterials Science, Institute of Dentistry, University of Turku
| | - Leila Perea-Lowery
- Department of Biomaterials Science, Institute of Dentistry, University of Turku
| | - Kalevi Vesterinen
- Technology Industry, Faculty of Engineering and Business, Turku University of Applied Sciences
| | - Auli Suominen
- Department of Community Dentistry, Institute of Dentistry, University of Turku
| | - Eija SÄilynoja
- Department of Biomaterials Science, Institute of Dentistry, University of Turku.,Scientific Affairs and Administration, Stick Tech Ltd. -a member of GC Group
| | - Pekka Kalevi Vallittu
- Department of Biomaterials Science, Institute of Dentistry, University of Turku.,City of Turku, Welfare Division
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Surface Electromyography as a Method for Diagnosing Muscle Function in Patients with Congenital Maxillofacial Abnormalities. JOURNAL OF HEALTHCARE ENGINEERING 2020; 2020:8846920. [PMID: 33029337 PMCID: PMC7527883 DOI: 10.1155/2020/8846920] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 11/24/2022]
Abstract
Electromyography (EMG) is the most objective and reliable method available for imaging muscle function and efficiency, which is done by identifying their electrical potentials. In global surface electromyography (sEMG), surface electrodes are located on the surface of the skin, and it detects superimposed motor unit action potentials from many muscle fibers. sEMG is widely used in orthodontics and maxillofacial orthopaedics to diagnose and treat temporomandibular disorders (TMD) in patients, assess stomatognathic system dysfunctions in patients with malocclusions, and monitor orthodontic therapies. Information regarding muscle sEMG activity in subjects with congenital maxillofacial abnormalities is limited. For this reason, the aim of this review is to discuss the usefulness of surface electromyography as a method for diagnosing muscle function in patients with congenital malformations of the maxillofacial region. Original papers on this subject, published in English between 1995 until 2020, are located in the MEDLINE/PubMed database.
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Zacher J, Bauer R, Hanie Krifka S, Rosentritt M. In vitro performance and fracture resistance of pressed or CAD/CAM milled ceramic implant-supported screw-retained or cemented anterior FDPs. J Prosthodont Res 2020; 65:208-212. [PMID: 32938865 DOI: 10.2186/jpr.jpor_2019_403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
PURPOSE This study investigated the in-vitro performance of anterior implant-supported fixed dental prostheses (FDP). The effect of ceramics, fabrication, finalization and the presence of a screw-channel wa s investigated. METHODS Identical anterior ceramic FDPs (tooth 11-13; n=80) were milled (Lithiumdisilicate (LiSiCAD, emaxCAD, Ivoclar-Vivadent), Lithiumaluminiumsilicate (LiAlSi, experimental material) or pressed (Lithiumdisilicate (LiSiPress, emaxPress, Ivoclar-Vivadent), Lithiumsilicate (ZLS, CeltraPress, Dentsply Sirona). FDP-groups (n=8 per material and group) simulated a cemented or screw-retained approach. After cementation or screwing on titanium abutments, thermal cycling and mechanical loading (TCML) was performed on all restorations to mimic 5-year clinical performance. Performance and fracture force were determined and failures were analyzed. STATISTICS (Kolmogorov-Smirnov-test, one-way-ANOVA; post-hoc-Bonferroni, multivariate-regression, α=0.05). RESULTS All FDPs survived TCML without aging, cracks, fractures or chipping. For FDPs without screw channel fracture values varied between with 839.8±112.3N (LiAlSi glazed) and 1485.9±232.6N (LiSiCAD). With screw channel, fracture results varied between 701.4±220.1N (LiALSi glazed) and 1516.3±253.7N (LiSipress). The type of material had a significant influence on the fracture results (LiSi>ZLS>LiAlSi; p≤0.012). Fabrication and finalization had no influence on the results. A screw channel did not significantly (p≥0.135) reduce the fracture force of the FDPs. Type of failure was mostly characterized by a fracture of the connector (LiSi, LiAlSi) or the abutment (ZLS, LiAlSi). CONCLUSIONS FDPs survived TCML without failures indicating that the in vitro performance was not influenced by the tested parameters. Composition of ceramic material has significant influence on the fracture resistance of implant supported LiSi based FDPs. Screw channel, fabrication or finalization did not weaken the FDPs.
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Affiliation(s)
- Julian Zacher
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg
| | - Robert Bauer
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg
| | - Step Hanie Krifka
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg
| | - Martin Rosentritt
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg
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de Moura MB, Loureiro KRT, Lima LB, Felippi C, Júnior PCS. Biomechanical behavior of three different types of internal tapered connections after cyclic and static loading tests: experimental in vitro. Int J Implant Dent 2020; 6:41. [PMID: 32696277 PMCID: PMC7374674 DOI: 10.1186/s40729-020-00228-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 05/25/2020] [Indexed: 11/10/2022] Open
Abstract
Abstract Background In the long-term success of a dental implant, the reliability and stability of the implant-abutment interface are important. Studies of maximum force of dental implants with different loading values have been used. This study aims to evaluate the influence of the oblique cyclic loading on the maximum force supported in one-piece and two-piece abutments installed on internal tapered implants. Findings Sixty implants and sixty prosthetic abutments were divided into six groups (n = 10): G1 and G2 (two-piece abutments with 16°), G3 and G4 (two-piece abutments with 11.5°), and G5 and G6 (one-piece abutments with 11.5°). A 2-Hz cyclic loading was applied to specimens of G2, G4, and G6, with a number of cycles of 2,400,000. All specimens were inclined by 30° from the vertical axis, and a vertical loading was applied over the tapered connections (ISO 14801). Then, the maximum force was tested by applying a static compression load on the specimens of the 6 groups tested (30°) at a rate of 0.5 mm/s. Statistical analysis was performed using the Shapiro-Wilk (p > 0.05) and Levene (p = 0.789) tests to determine if the data presented homoscedasticity and the Tukey test for multiple comparisons. Tukey test showed that the maximum force supported by G1 and G2 was not affected by the cyclic load, while in G3 and G4 it decreased significantly when subjected to the cyclic load. The G5 and G6 had a significant increase in maximum force supported when subjected to cyclic load. Conclusions Cyclic loading influenced the maximum force supported of G4 and G6 but did not influence G2.
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Affiliation(s)
- Marcos Boaventura de Moura
- Department of Occlusion, Fixed Prosthodontics and Dental Materials, School of Dentistry, Federal University of Uberlandia, Av. Pará 1720, Bloco 4LB, sala 39, Uberlandia, MG, 38405-902, Brazil.
| | - Karine Regina Tolesano Loureiro
- Department of Occlusion, Fixed Prosthodontics and Dental Materials, School of Dentistry, Federal University of Uberlandia, Av. Pará 1720, Bloco 4LB, sala 39, Uberlandia, MG, 38405-902, Brazil
| | - Livia Bonjardim Lima
- Department of Occlusion, Fixed Prosthodontics and Dental Materials, School of Dentistry, Federal University of Uberlandia, Av. Pará 1720, Bloco 4LB, sala 39, Uberlandia, MG, 38405-902, Brazil
| | - Christian Felippi
- Department of Mechanical Engineering, University Federal of Paraná, Curitiba, PR, Brazil
| | - Paulo Cézar Simamoto Júnior
- Department of Occlusion, Fixed Prosthodontics and Dental Materials, School of Dentistry, Federal University of Uberlandia, Av. Pará 1720, Bloco 4LB, sala 39, Uberlandia, MG, 38405-902, Brazil
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Abdulmajeed A, Sulaiman T, Abdulmajeed A, Bencharit S, Närhi T. Fracture Load of Different Zirconia Types: A Mastication Simulation Study. J Prosthodont 2020; 29:787-791. [PMID: 32840940 DOI: 10.1111/jopr.13242] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2020] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To assess the effect of yttria mol% concentration and material thickness on the biaxial fracture load (N) of zirconia with and without mastication simulation. MATERIALS AND METHODS Disk-shaped specimens (N = 120) of 3 mol% yttria-partially stabilized zirconia, 3Y-PSZ (Katana High Translucent, Kuraray Noritake), 4 mol% yttria-partially stabilized zirconia, 4Y-PSZ (Katana Super Translucent Multi Layered) and 5 mol% Yttria-partially stabilized zirconia, 5Y-PSZ (Katana Ultra Translucent Multi Layered) were prepared to thicknesses of 0.7 and 1.2 mm. For each thickness, the biaxial fracture load (N) was measured with and without mastication simulation with 1.2 million cycles at a 110-N load and simultaneous thermal cycling at 5°C to 55°C. The data were analyzed by three-way Analysis of Variance (α = 0.05) and Tukey-Kramer adjusted multiple comparison test. RESULTS Yttria mol% concentration and material thickness had a statistically significant effect on the mean biaxial fracture load (F = 388.16, p < 0.001 and F = 714.33, p < 0.001 respectively). The mean biaxial fracture load ranged from the highest to the lowest; 3Y-PSZ, 4Y-PSZ, and 5Y-PSZ (p = 0.012). The mean biaxial fracture load of the 1.2 mm thickness groups was significantly higher than 0.7 mm thickness at any given condition (p = 0.002). Not all specimens survived the mastication simulation protocol. Fifty percent of the 0.7-mm-thick 4Y-PSZ specimens, 70% of the 0.7-mm-thick 5Y-PSZ specimens and 20% of 1.2-mm-thick 5Y-PSZ specimens fractured during mastication simulation. Mastication simulation had no statistically significant effect on the biaxial fracture load (F = 1.24, p = 0.239) of the survived specimens. CONCLUSIONS Lowering yttria mol% concentration and increasing material thickness significantly increases the fracture load of zirconia. At 0.7 mm thickness, only 3Y-PSZ survived masticatory simulation. A minimum material thickness of 1.2 mm is required for 4Y-PSZ or 5Y-PSZ.
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Affiliation(s)
- Awab Abdulmajeed
- Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland.,Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, VA
| | - Taiseer Sulaiman
- Division of Comprehensive Oral Health, Adams School of Dentistry, University of North Carolina, Chapel Hill, NC
| | - Aous Abdulmajeed
- Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland.,Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, VA
| | - Sompop Bencharit
- Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, VA.,Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, VA
| | - Timo Närhi
- Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland.,City of Turku, Welfare Division, Turku, Finland
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Assessment of Masticatory Muscle Function in Patients with Bilateral Complete Cleft Lip and Palate and Posterior Crossbite by means of Electromyography. JOURNAL OF HEALTHCARE ENGINEERING 2020; 2020:8828006. [PMID: 32908658 PMCID: PMC7474777 DOI: 10.1155/2020/8828006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 08/18/2020] [Indexed: 11/17/2022]
Abstract
Aim The aim of this study was to evaluate the electrical activity of the masticatory muscles in children with a bilateral complete cleft lip and palate (BCCLP) and posterior crossbite as well as in noncleft subjects with no malocclusion. Another purpose of the study was to examine the possible factors associated with this muscle activity. Methods The study included 52 children with mixed dentition and Class I occlusions (20 patients with nonsyndromic BCCLP and 32 subjects with no clefts). All the cleft patients had posterior crossbite. The surface electromyography (sEMG) was used to identify the electrical potentials of the temporalis and masseter muscles. The electromyographical (EMG) recordings were taken with a DAB-Bluetooth Instrument (zebris Medical GmbH, Germany) at rest and during maximum voluntary clenching (MVC). The relationships between muscle EMG activity and independent variables were identified through multivariate logistic regression analysis. Results The EMG activity of the temporalis muscles at rest was significantly higher in BCCLP patients with malocclusion in comparison with the noncleft subjects with normal occlusion. During MVC, significantly lower electrical potentials of the temporalis and masseter muscles were observed in cleft patients compared to the noncleft group. The presence of BCCLP, unilateral posterior crossbites, increased vertical overlap, and increased overjet are factors strongly associated with higher temporalis muscle EMG activity at rest. Conclusion The use of surface electromyography in imaging muscle function showed that children with BCCLP and posterior crossbite exhibited altered masticatory muscle potentials at rest and during clenching. The presence of unilateral posterior crossbites, increased vertical overlap, and increased overjet had a significant impact on temporalis muscle activity in cleft patients. This knowledge is important in the aspect of early and proper diagnosis and orthodontic treatment of malocclusions, thereby achieving correct occlusion and improvement in muscle function.
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