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Ahlers MO, Cachovan G, Jakstat HA, Edelhoff D, Roehl JC, Platzer U. Freehand vs. depth-gauge rotary instruments for veneer preparation: A controlled randomized simulator study. J Prosthodont Res 2024; 68:407-414. [PMID: 37853627 DOI: 10.2186/jpr.jpr_d_22_00317] [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: 10/20/2023]
Abstract
PURPOSE To investigate whether depth-gauge burs in veneer preparations influence preparation depth in a randomized, controlled, single-blinded trial and whether inexperienced operators can perform adequate veneer preparations. METHODS Participants were 20 undergraduate dental students with no prior veneer preparation experience. The instruments used were the "Laminate Veneer System" (LVS), "Keramik-Veneers. de" (KVD), and a "Freehand" group (FH) for reference. All participants prepared three educational acrylic resin maxillae and three mandibular central incisors mounted in typodonts in patient simulators. The objectives were to achieve a preparation depth of 0.6 mm (tooth 11) and 0.4 mm (tooth 31). The sequences of the instruments used and prepared teeth were randomized. The measurements were performed using a laser triangulation coordinate-measuring machine. The data were stratified according to tooth location. RESULTS The preparation depths of both depth-gauge-instrument-groups LVS and KVD achieved the objectives significantly better than did the instruments from the "Freehand" group (P < 0.001). The differences between the depth gauge groups were insignificant, although the maximum preparation depths were smaller in the KVD group. Regarding the prepared teeth, the preparation depths in the mandibular incisors were lower, and the differences were smaller. CONCLUSIONS The use of special depth-gauge burs for initial veneer preparation leads to significantly lower preparation depths than "Freehand" preparations. The tapered instruments resulted in a lower incidence of extreme preparation depths. The inexperienced operators performed veneer preparation remarkably well.
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Affiliation(s)
- M Oliver Ahlers
- Department of Prosthetic Dentistry, Center for Dental and Oral Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- CMD-Center Hamburg-Eppendorf, Hamburg, Germany
| | - Georg Cachovan
- Oral Healthcare DACH, Philips GmbH, Hamburg, Germany
- Department of Periodontics, Preventive and Restorative Dentistry, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Holger A Jakstat
- Department of Prosthetic Dentistry and Dental Materials and Special Care, Center for Dental and Oral Medicine, University of Leipzig, Leipzig, Germany
| | - Daniel Edelhoff
- Department of Prosthetic Dentistry, University Hospital LMU Ludwig-Maximilians, Munich, Germany
| | | | - Ursula Platzer
- Department of Periodontics, Preventive and Restorative Dentistry, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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de Andrade GS, Luz JN, Tribst JPM, Chun EP, Bressane A, Borges ALS, Saavedra GDSFA. Impact of different complete coverage onlay preparation designs and the intraoral scanner on the accuracy of digital scans. J Prosthet Dent 2024; 131:1168-1177. [PMID: 35717209 DOI: 10.1016/j.prosdent.2022.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 05/06/2022] [Accepted: 05/09/2022] [Indexed: 11/18/2022]
Abstract
STATEMENT OF PROBLEM The trueness and precision of intraoral scanners (IOSs) and the effect of intracoronal restorations have been reported. However, studies addressing the accuracy of IOSs in reproducing different complete coverage onlay preparation designs are lacking. PURPOSE The purpose of this in vitro study was to evaluate the influence of complete coverage onlay preparation design and intraoral scanning devices on the accuracy of digital scans in terms of trueness and precision. MATERIAL AND METHODS Three preparation designs on the mandibular first molar were considered: a traditional preparation design with isthmus reduction (IST), a traditional preparation design without isthmus reduction (wIST), and simplified nonretentive preparation (nRET). Digital scans of epoxy resin mandibular arch reference models of the preparations (containing second premolar, first molar, and second molar) were obtained by using 3 IOSs (iTero Element 2 [ELE], TRIOS 3 [TRI], and Primescan [PRI]) (n=10). Trueness (μm) and precision (μm) were analyzed by superimposing the digital scan on the digital reference models obtained with a high-accuracy industrial scanner (ATOS Core 80) in a tridimensional metrology software program. Accuracy was quantified by the absolute deviation (μm). Local and overall mean positive and negative deviations for trueness were also obtained. Data were analyzed by using the Kruskal-Wallis and Dunn tests with a statistical software program (α=.05). RESULTS The nonretentive preparation groups obtained higher trueness (3.8 μm) and precision (2.7 μm) than the IST and wIST groups (trueness=7.5 to 6.3 μm, precision=5.5 to 4.6 μm). Trueness values were lower with ELE×IST (16 μm), followed by ELE×wIST (13 μm), and PRI×IST (7.8 μm). In general, no difference was found between PRI and TRI scanners (6.3 to 5.9 μm), with lower performance for ELE (13 μm). Positive deviations were higher on the proximal box of the IST and wIST preparation and on the occlusal box of the IST group. Negative deviation was higher on the ELE×IST occlusal box. CONCLUSIONS Different intraoral scanners and preparation designs influenced the accuracy of digital scans. A more complex preparation such as IST and wIST showed higher deviation. The iTero Element 2 scanner exhibited higher deviation for both trueness and precision.
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Affiliation(s)
- Guilherme Schmitt de Andrade
- Assistant Professor, Center of Biological and Health Sciences, School of Dentistry, Western Paraná State University (Unioeste), Cascavel, PR, Brazil.
| | - Julio Nogueira Luz
- Assistant Professor, Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University - UNESP, São José dos Campos, SP, Brazil; Adjunct Professor, Department of Dentistry, School of Dentistry, University of Guarulhos (UNG), Guarulhos, SP, Brazil
| | - João Paulo Mendes Tribst
- Assistant Professor, Department of Dental Materials, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Eliseo Pablo Chun
- Faculty, School of Dentistry, Espiritu Santo University, Samborondon, Ecuador
| | - Adriano Bressane
- Associate Professor, Applied Oral Health Sciences Post-Graduate Program, Institute of Science and Technology, São Paulo State University (UNESP), São José dos Campos, SP, Brazil
| | - Alexandre Luiz Souto Borges
- Associate Professor, Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (UNESP), São José dos Campos, SP, Brazil
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Suksawat N, Angwaravong O, Angwarawong T. Fracture resistance and fracture modes in endodontically treated maxillary premolars restored using different CAD-CAM onlays. J Prosthodont Res 2024; 68:290-298. [PMID: 37225522 DOI: 10.2186/jpr.jpr_d_22_00311] [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: 05/26/2023]
Abstract
PURPOSE To examine the fracture resistance and fracture modes of endodontically treated teeth (ETT) restored using onlays of different materials fabricated using computer-aided design and computer-aided manufacturing (CAD-CAM). METHODS Sixty maxillary first premolars were randomly assigned to six groups (n=10). The first group comprised intact teeth (INT). The remaining premolars were prepared for mesio-occluso-distal cavity and root canal treatments. Group 2 was treated using polymer-reinforced zinc oxide-eugenol intermediate restorative material (IRM). Groups 3-6 were core build-up, prepared for onlay, and restored using resin nanoceramic (Cerasmart [CER]), polymer-infiltrated ceramic networks (Vita Enamic [VE]), lithium disilicate-based ceramic (IPS e.max CAD [EM]), or translucent zirconia (Katana Zirconia UTML [KZ]). All specimens were immersed in 37 °C distilled water for 24 h. Each specimen was loaded at 45° to the long axis until failure (crosshead speed, 0.5 mm/min). Fracture loads were analyzed using one-way analysis of variance and Tukey's post-hoc test (α=0.05). RESULTS There were no significant differences in fracture load among the INT, CER, VE, and EM groups. The fracture load in the KZ group was significantly higher than those in the other groups (P < 0.05). Fracture load was the lowest in the IRM group (P < 0.05). The unrestorable failure rate was 70% in the KZ group and 10-30% in the other experimental groups. CONCLUSIONS ETT restored using Cerasmart, Vita Enamic, or IPS e.max CAD onlays had fracture resistance and patterns comparable to those of intact teeth. Katana Zirconia UTML-restored ETT had the highest fracture load but also a higher unrestorable failure rate.
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Affiliation(s)
- Nuntana Suksawat
- Department of Prosthodontics, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Onauma Angwaravong
- Division of Pediatric Dentistry, Department of Preventive Dentistry, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Thidarat Angwarawong
- Department of Prosthodontics, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
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Figueiredo PS, Spazzin AO, Bacchi A, Alessandretti R. Effect of preheating and ultrasound application of resin-based luting agents on the failure load of a lithium disilicate glass-ceramic. J Prosthodont 2024; 33:396-401. [PMID: 37300878 DOI: 10.1111/jopr.13722] [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: 06/21/2022] [Accepted: 05/31/2023] [Indexed: 06/12/2023] Open
Abstract
PURPOSE To assess the effect of preheating resin-based materials and ultrasound application on the failure load of a lithium disilicate glass-ceramic. MATERIALS AND METHODS Ninety ceramic specimens were produced (14×12×1.0 mm) and divided into 9 groups (n = 10) to be bonded to a dentin analog (Nema G10) with light-cured luting agent (LC), flowable resin composite (FL), and supra-nano filled resin composite (SN), as follows: LC/R - LC at room temperature; LC/P - preheated LC; LC/P/U - preheated LC and Ultrasound; FL/R - FL at room temperature; FL/P - preheated FL; FL/P/U - preheated FL and Ultrasound; SN/R - SN at room temperature; SN/P - preheated SN; SN/P/U - preheated SN and Ultrasound. The failure load test was performed in a universal testing machine with the aid of acoustic detection. The data was analyzed with two-way ANOVA (for failure load) and Weibull statistics (Weibull modulus - m and characteristic strength, based on 95% confidence intervals - CI). RESULTS The analyses of failure load revealed no statistically significant difference among groups considering the type of luting agent (P = 0.075; F = 2,673), the application method (P = 0.772; F = 2,259), and the interaction between them (P = 0.297; F = 1,248). The characteristic strength did not show differences among groups (95% CI). The m, which indicates structural reliability, showed lower values for SN/P/U and SN/P, with a difference from other selected groups (95% CI). CONCLUSION Preheating of resin-based materials and ultrasound application did not affect the failure load of lithium disilicate glass-ceramic. Lower reliability was observed with supra-nano filled resin composite.
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Affiliation(s)
| | - Aloísio Oro Spazzin
- Graduate Program in Dentistry, School of Dentistry, Atitus Education, Passo Fundo, RS, Brazil
| | - Atais Bacchi
- Graduate Program in Dentistry, Paulo Picanço School of Dentistry (FACPP), Fortaleza, CE, Brazil
| | - Rodrigo Alessandretti
- Graduate Program in Dentistry, School of Dentistry, Atitus Education, Passo Fundo, RS, Brazil
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Abdelhady WA, Metwally MF, Haggag KM. Effect of thermomechanical loading on fracture resistance and failure mode of new pressable zirconia-reinforced lithium disilicate onlay restoration. J Dent Res Dent Clin Dent Prospects 2024; 18:29-36. [PMID: 38881646 PMCID: PMC11179138 DOI: 10.34172/joddd.40843] [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: 11/17/2023] [Accepted: 01/29/2024] [Indexed: 06/18/2024] Open
Abstract
Background Insufficient information exists regarding the fracture resistance and failure pattern of newly developed zirconia-reinforced lithium disilicate (ZL, Vita Ambria) onlays. This in vitro study compared the fracture resistance of two types of onlays: monolithic lithium disilicate (LD) and monolithic ZL. Methods Forty-eight ceramic onlay restorations were fabricated on epoxy dies using a maxillary first premolar model. The samples were divided into two main groups: LD and ZL. Half of each group was subjected to thermomechanical fatigue loading (TML) using a chewing simulator. All the samples were cemented with self-adhesive resin cement. Subsequently, they were loaded until failure in a universal testing machine, and the fracture patterns and resistance were recorded. Results Before TML, ZL demonstrated the highest statistically significant mean fracture resistance (499.76±34.14N) compared to LD (470.40±27.38N). After TML, ZL showed the highest non-statistically significant mean fracture resistance (429.27±131.42N), while LD's mean fracture resistance decreased (377.31±62.18N). Conclusion Monolithic zirconia-reinforced onlays demonstrated higher fracture resistance and a more favorable failure mode compared to LD. However, the impact of thermomechanical aging resulted in reduced fracture resistance for both materials, with a notable preference observed for ZL.
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Affiliation(s)
- Walid A Abdelhady
- Crown and Bridge Department, Faculty of Dental Medicine, Al Azhar University, Cairo, Egypt
| | - Mohamed F Metwally
- Crown and Bridge Department, Faculty of Dental Medicine, Al Azhar University, Cairo, Egypt
| | - Khaled M Haggag
- Crown and Bridge Department, Faculty of Dental Medicine, Al Azhar University, Cairo, Egypt
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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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Spitznagel F, Prott L, Hoppe J, Manitckaia T, Blatz M, Zhang Y, Langner R, Gierthmuehlen P. Minimally invasive CAD/CAM lithium disilicate partial-coverage restorations show superior in-vitro fatigue performance than single crowns. J ESTHET RESTOR DENT 2024; 36:94-106. [PMID: 38009505 PMCID: PMC10872741 DOI: 10.1111/jerd.13169] [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: 09/30/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 11/29/2023]
Abstract
OBJECTIVE To analyze the influence of restoration design (partial-coverage restoration vs. crown) and ceramic layer thickness on the performance and failure loads of CAD/CAM-fabricated lithium disilicate (LDS) reconstructions on molars after fatigue. MATERIALS AND METHODS Seventy-two posterior monolithic CAD/CAM-fabricated LDS restorations (IPS e.max CAD, Ivoclar Vivadent) with different occlusal/buccal ceramic layer thicknesses (1.5/0.8, 1.0/0.6, and 0.5/0.4 mm) and restoration designs (PCR: non-retentive full-veneer/partial-coverage restoration, C: crown,) were investigated and divided into six groups (n = 12, test: PCR-1.5, PCR-1.0, PCR-0.5; control: C-1.5, C-1.0, C-0.5). LDS restorations were adhesively bonded (Variolink Esthetic DC, Ivoclar Vivadent) to dentin-analogue composite dies (Z100, 3M ESPE). All specimens were subjected to thermomechanical loading (1.2 million cycles, 49 N, 1.6 Hz, 5-55°C) and exposed to single load to failure testing. Failure analysis was performed with light and scanning electron microscopies. Data were statistically analyzed using ANOVA, Tukey-Test, and t-test (p < 0.05). RESULTS Eight crown samples (C-0.5) and one PCR specimen (PCR-0.5) revealed cracks after fatigue, resulting in an overall success rate of 87.5% (crowns: 75%, PCRs: 96.88%). Direct comparisons of PCRs versus crowns for thicknesses of 0.5 mm (p < 0.001) and 1.0 mm (p = 0.004) were significant and in favor of PCRs. Minimally invasive PCRs (0.5 and 1.0 mm) outperformed crowns with the identical ceramic thickness. No difference was detected (p = 0.276) between thickness 1.5 mm PCRs and crowns. CONCLUSIONS Minimally invasive monolithic CAD/CAM-fabricated posterior LDS PCRs (0.5 and 1.0 mm) resulted in superior failure load values compared to minimally invasive crowns. Minimally invasive crowns (0.5 mm) are prone to cracks after fatigue. CLINICAL SIGNIFICANCE Minimally invasive CAD/CAM-fabricated LDS PCR restorations with a non-retentive preparation design should be considered over single crowns for molar rehabilitation.
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Affiliation(s)
- F.A. Spitznagel
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
- Department of Preventive and Restorative Sciences, Penn Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - L.S. Prott
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
| | - J.S. Hoppe
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
| | - T. Manitckaia
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
| | - M.B. Blatz
- Department of Preventive and Restorative Sciences, Penn Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Y. Zhang
- Department of Preventive and Restorative Sciences, Penn Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - R. Langner
- Institute of Systems Neuroscience, Medical Faculty, Heinrich-Heine-University Düsseldorf, Germany
- Institute of Neuroscience and Medicine, Brain and Behavior (INM-7), Research Center Jülich, Germany
| | - P.C. Gierthmuehlen
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
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Demirel MG, Mohammadi R, Keçeci M. Crack Propagation and Fatigue Performance of Partial Posterior Indirect Restorations: An Extended Finite Element Method Study. J Funct Biomater 2023; 14:484. [PMID: 37754898 PMCID: PMC10532640 DOI: 10.3390/jfb14090484] [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: 08/30/2023] [Revised: 09/13/2023] [Accepted: 09/18/2023] [Indexed: 09/28/2023] Open
Abstract
Dental ceramics are susceptible to slow, progressive crack growth after cyclic loading. The purpose of this study was to investigate the progressive patterns of cracks in two different types of CAD/CAM ceramic materials used with three different partial posterior indirect restoration (PPIR) designs and to determine the materials' failure risk using a fatigue test. Standard initial cracks were formed in Standard Tessellation Language (STL) files prepared for three different PPIRs. The materials chosen were monolithic lithium disilicate (LS) and polymer-infiltrated ceramic networks (PICNs). The extended finite element method (XFEM) was applied, and the fatigue performance was examined by applying a 600 N axial load. The cracks propagated the most in onlay restorations, where the highest displacement was observed. In contrast, the most successful results were observed in overlay restorations. Overlay restorations also showed better fatigue performance. LS materials exhibited more successful results than PICN materials. LS materials, which can be used in PPIRs, yield better results compared to PICN materials. While inlay restorations demonstrated relatively successful results, overlay and onlay restorations can be specified as the most and the least successful PPIR types, respectively.
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Affiliation(s)
| | - Reza Mohammadi
- Faculty of Dentistry, Necmettin Erbakan University, Konya 42090, Turkey;
| | - Murat Keçeci
- Department of Prosthodontics, Faculty of Dentistry, Karamanoğlu Mehmet Bey University, Karaman 70000, Turkey;
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Zahran M, Abo El-Farag S, Soltan H, Attia A. Fracture load of ultrathin occlusal veneers: Effect of thickness and surface conditioning. J Mech Behav Biomed Mater 2023; 145:106030. [PMID: 37473575 DOI: 10.1016/j.jmbbm.2023.106030] [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: 06/02/2023] [Revised: 07/12/2023] [Accepted: 07/15/2023] [Indexed: 07/22/2023]
Abstract
OBJECTIVE This in-vitro study is planned to analyze the effect of different thicknesses of ceramic occlusal veneers and different surface treatments on fracture resistance. MATERIALS AND METHODS A total of 48 sound mandibular molars are anatomically prepared from the occlusal surface with two different thicknesses (1.0 and 0.5 mm). CAD/CAM zirconia-reinforced glass ceramic blocks (Vita Suprinity) are used for fabricating occlusal veneers. The teeth are randomly divided into two primary groups A and B (n=24) according to occlusal veneer thickness. Each group is subdivided according to surface conditioning into three equal subgroups (n=8)-subgroup HF: etching with hydrofluoric acid and ceramic primer application; subgroup APF: etching with acidulated phosphate fluoride and ceramic primer application; subgroup EP: conditioning with etch and prime only. Dual-cure adhesive resin cement (Multilink Automix) is utilized to adhesively bond the veneers. All specimens are subjected to 240,000 cycles of dynamic load aging prior to the fracture resistance test. The fracture resistance is measured in Newton (N). The Failure mode patterns are analyzed and categorized using a scanning electron microscope (SEM). The results are analyzed using a two-way ANOVA with Bonferroni's Post-Hoc test, followed by a one-way ANOVA for each factor. That is in addition to one-way ANOVA for surface treatment under each thickness, each followed by Bonferroni's Post-Hoc test. Then, a T-test is used to compare the two thicknesses under each surface treatment. All tests are set at 0.05 significance level. RESULTS The two-way ANOVA test revealed that restoration thickness and surface treatment both significantly affect the fracture resistance values (p<0.05). The highest fracture resistance mean (2672±216N) is obtained from HF at 1.0 mm thickness, while the lowest mean (2104±299N) is obtained from APF at 0.5 mm thickness. CONCLUSION All test groups, regardless of thickness, demonstrated fracture resistance values that exceeded both normal and parafunctional bite forces. The veneers that bonded after hydrofluoric acid etching followed by ceramic primer application showed more favourable fracture patterns.
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Affiliation(s)
- Maged Zahran
- Department of Fixed Prosthodontics, Faculty of Dentistry, Mansoura University, Mansoura 35516, Egypt.
| | - Shaimaa Abo El-Farag
- Department of Fixed Prosthodontics, Faculty of Dentistry, Mansoura University, Mansoura 35516, Egypt.
| | - Hassan Soltan
- Production and Mechanical Design Engineering Department, Faculty of Engineering, Mansoura University, Mansoura 35516, Egypt.
| | - Ahmed Attia
- Department of Fixed Prosthodontics, Faculty of Dentistry, Mansoura University, Mansoura 35516, Egypt.
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10
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Salah Z, Sleibi A. Effect of deep margin elevation on fracture resistance of premolars restored with ceramic onlay: In vitro comparative study. J Clin Exp Dent 2023; 15:e446-e453. [PMID: 37388433 PMCID: PMC10306389 DOI: 10.4317/jced.60384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 04/12/2023] [Indexed: 07/01/2023] Open
Abstract
Background This in vitro comparative study aimed to compare the influence of two levels of deep margin elevation (2 and 3 mm) with either bulk-fill flowable composite or short fiber-reinforced flowable composite on the fracture resistance of maxillary first premolars restored with ceramic onlays. Material and Methods Fifty sound-extracted maxillary first premolar teeth were selected to prepare mesio-occluso-distal cavities with standardized dimensions. The cervical margins were extended 2 mm below the cemento-enamel junction on both mesial and distal sides. These teeth were randomly divided into five groups: Group I: no box elevation (control group). Group II: 2 mm marginal elevation with bulk-fill flowable composite. Group III: 2 mm marginal elevation with short fiber-reinforced flowable composite. Group IV: 3 mm marginal elevation with bulk-fill flowable composite. Group V: 3 mm marginal elevation with short fiber-reinforced flowable composite. After cementation, all teeth were subjected to a fracture resistance test using the universal testing machine, and the mode of failure was analyzed using a digital microscope at 20x magnification. Results The result showed a non-significant difference in the fracture resistance between 2 and 3 mm marginal elevation (p>0.05) with respect to each restorative material used for deep margin elevation. However, the fracture resistance of teeth elevated with short fiber-reinforced flowable composite was significantly higher than those elevated with bulk-fill flowable composite at both levels 2 and 3 mm, p=0.041 and 0.038 respectively. Conclusions The fracture resistance of premolars restored with a ceramic onlay was not influenced by the levels of deep margin elevation (2 or 3 mm). However, marginal elevation with short fiber-reinforced flowable composites provided higher fracture resistance than those elevated with bulk-fill flowable composites, and those without marginal elevation. Key words:Fracture Resistance, Short fiber reinforced flowable composite, Bulk-fill flowable composite, Ceramic onlay, Cervical margin elevation.
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Affiliation(s)
- Zahraa Salah
- MSc researcher, Department of Conservative Dentistry, College of Dentistry, Mustansiriyah University, Baghdad, Iraq. Health Center Al-Taji first, Department health of Baghdad Karkh, Iraqi Ministry of Health
| | - Ahmed Sleibi
- Department of conservative dentistry, College of Dentistry, Mustansiriyah University, Baghdad, Iraq
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Fouda AM, Atta O, Özcan M, Stawarczyk B, Glaum R, Bourauel C. An investigation on fatigue, fracture resistance, and color properties of aesthetic CAD/CAM monolithic ceramics. Clin Oral Investig 2023; 27:2653-2665. [PMID: 36574045 PMCID: PMC10264477 DOI: 10.1007/s00784-022-04833-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 12/18/2022] [Indexed: 12/28/2022]
Abstract
OBJECTIVES To evaluate and compare fracture resistance, translucency, and color reproducibility, as well as the effect of aging on the fracture load and color stability of novel monolithic CAD/CAM ceramics. MATERIALS AND METHODS One hundred crowns of uniform thickness were milled from five ceramic blocks (n = 20): partially crystallized lithium disilicate (PLD) and fully crystallized lithium disilicate (FLD), lithium metasilicate (LMS), 4Y-TZP (SMZ), and 5Y-TZP (UMZ) monolithic zirconia. PLD crowns were glazed, LMS was fired, and FLD was polished. SMZ and UMZ crowns were sintered and polished. Crowns were adhesively cemented to epoxy dies. Half of the crowns (n = 10) were subjected to 1.200.000 load cycles with thermal cycling. Color space values L, a, b defined by the Commission Internationale de l´Eclairage (CIELAB) were measured before and after aging, and (∆E) was calculated. Both aged and non-aged specimens were loaded until fracture in a universal testing machine and the fracture load was recorded. X-ray diffraction (XRD) and scanning electron microscope (SEM) fractographic analysis were carried out on fractured fragments of representative samples. For translucency and color reproducibility, 50 rectangular-shaped specimens were fabricated and processed as described previously. Color values were measured over black and white backgrounds, and the translucency parameter (TP) was computed. Using the shade verification mode, (∆E) to shade A3 was calculated. Data were statistically analyzed using one-way and two-way ANOVA, and t-test. RESULTS Aging did not affect fracture resistance significantly (p > 0.05). The highest mean fracture load was obtained for the SMZ and UMZ. A significant color change was observed after aging in all groups. The highest TP was noted for FLD. SMZ and UMZ had the best shade match. CONCLUSIONS Zirconia showed higher fracture resistance and color stability than lithium silicate ceramics. Lithium silicate ceramics were more translucent. The experimental FLD demonstrated high translucency. CLINICAL RELEVANCE Tested ceramics showed sufficient stability to withstand masticatory forces. Characterization of final restorations might be mandatory for better color match.
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Affiliation(s)
- Ahmed Mahmoud Fouda
- Department of Oral Technology, University Hospital Bonn, Bonn University, Welschnonnenstr. 17, 53111, Bonn, Germany.
- Department of Fixed Prosthodontics, Suez Canal University, Ismailia, Egypt.
| | - Osama Atta
- Department of Fixed Prosthodontics, Suez Canal University, Ismailia, Egypt
| | - Mutlu Özcan
- Division of Dental Biomaterials, Center for Dental Medicine, Clinic for Reconstructive Dentistry, University of Zurich, Zurich, Switzerland
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany
| | - Robert Glaum
- Institute of Inorganic Chemistry, Bonn University, Bonn, Germany
| | - Christoph Bourauel
- Department of Oral Technology, University Hospital Bonn, Bonn University, Welschnonnenstr. 17, 53111, Bonn, Germany
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12
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Alshamrani A, Alhotan A, Owais A, Ellakwa A. The Clinical Potential of 3D-Printed Crowns Reinforced with Zirconia and Glass Silica Microfillers. J Funct Biomater 2023; 14:jfb14050267. [PMID: 37233377 DOI: 10.3390/jfb14050267] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/09/2023] [Accepted: 05/09/2023] [Indexed: 05/27/2023] Open
Abstract
The development of 3D-printed crown resin materials with improved mechanical and physical properties is an area of growing interest in dentistry. This study aimed to develop a 3D-printed crown resin material modified with zirconia glass (ZG) and glass silica (GS) microfillers to enhance overall mechanical and physical properties. A total of 125 specimens were created and divided into five groups: control unmodified resin, 5% either ZG or GS reinforced 3D-printed resin, and 10% either ZG or GS reinforced 3D-printed resin. The fracture resistance, surface roughness, and translucency parameter were measured, and fractured crowns were studied under a scanning electron microscope. The results showed that 3D-printed parts that were strengthened with ZG and GS microfillers demonstrated comparable mechanical performance to unmodified crown resin but resulted in greater surface roughness, and only the group that contained 5% ZG showed an increase in translucency. However, it should be noted that increased surface roughness may impact the aesthetics of the crowns, and further optimisation of microfillers concentrations may be necessary. These findings suggest that the newly developed dental-based resins that incorporate microfillers could be suitable for clinical applications, but further studies are necessary to optimise the nanoparticle concentrations and investigate their long-term clinical outcomes.
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Affiliation(s)
- Abdullah Alshamrani
- Oral Rehabilitation & Dental Biomaterial and Bioengineering, The University of Sydney, Sydney, NSW 2006, Australia
- Department of Dental Health, College of Applied Medical Sciences, King Saud University, Riyadh P.O. Box 12372, Saudi Arabia
| | - Abdulaziz Alhotan
- Department of Dental Health, College of Applied Medical Sciences, King Saud University, Riyadh P.O. Box 12372, Saudi Arabia
| | - Ahmed Owais
- The X-ray Spectroscopy Node, Sydney Analytical, Core Research Facilities, The University of Sydney, Sydney, NSW 2006, Australia
| | - Ayman Ellakwa
- Oral Rehabilitation & Dental Biomaterial and Bioengineering, The University of Sydney, Sydney, NSW 2006, Australia
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13
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Ille C, Moacă EA, Pop D, Goguță L, Opriș C, Pîrvulescu IL, Avram L, Faur A, Jivănescu A. Compressive strength evaluation of thin occlusal veneers from different CAD/CAM materials, before and after acidic saliva exposure. Odontology 2023; 111:360-374. [PMID: 36097129 PMCID: PMC10020293 DOI: 10.1007/s10266-022-00741-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 09/02/2022] [Indexed: 01/09/2023]
Abstract
In the present study are depicted valuable observations for practitioners, obtained from an in vitro study which aims to evaluate the compressive strength of occlusal veneers fabricated from 3 type of restorative materials, before and after 1 month of acidic artificial saliva exposure (pH = 2.939). In this context, 90 extracted human molars were prepared to receive computer-aided design/computer-aided manufacturing (CAD/CAM) occlusal veneers. The restorative materials considered in this study were: Cerasmart; Straumann Nice and Tetric CAD. The occlusal veneers were designed, milled and cemented with an adhesive dual-cure resin cement. From all the extracted human molars, only sixty specimens were immersed in acidic artificial saliva, for 1 month, at 37 °C ± 1 °C and part of this specimens were also thermo-cycled, between 5 and 55 °C ± 2 °C, before compressive strength test. The results showed a lower compressive strength for both the samples exposed to acidic artificial saliva as well as for the samples exposed to acidic artificial saliva and thermo-cycled. Scanning electron microscopy (SEM) showed that after compressive strength, all the specimens non-exposed to acidic artificial saliva, present extensive cracks formation at the surface of the restorations, and after exposure to acidic artificial saliva for 1 month, the surface damage was characterized by longitudinal and profound fractures of the restoration, as well as the fracture of the tooth structure. Between CAD/CAM materials tested, nanoceramic resin shows more favorable fracture patterns, both before and after acidic artificial saliva exposure.
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Affiliation(s)
- Codruța Ille
- Department of Prosthodontics, Faculty of Dental Medicine, “Victor Babes” University of Medicine and Pharmacy, Revolutiei Ave. 1989, No. 9, 300580 Timișoara, Romania
- TADERP Research Center—Advanced and Digital Techniques for Endodontic, Restorative and Prosthetic Treatment, “Victor Babeș” University of Medicine and Pharmacy, Revolutiei Ave. 1989, No. 9, 300041 Timişoara, Romania
| | - Elena-Alina Moacă
- Department of Toxicology and Drug Industry, Faculty of Pharmacy, “Victor Babeș” University of Medicine and Pharmacy Timisoara, 2nd Eftimie Murgu Square, 300041 Timisoara, Romania
- Research Centre for Pharmaco-Toxicological Evaluation, “Victor Babeș” University of Medicine and Pharmacy, 2nd Eftimie Murgu Square, 300041 Timișoara, Romania
| | - Daniel Pop
- Department of Prosthodontics, Faculty of Dental Medicine, “Victor Babes” University of Medicine and Pharmacy, Revolutiei Ave. 1989, No. 9, 300580 Timișoara, Romania
- TADERP Research Center—Advanced and Digital Techniques for Endodontic, Restorative and Prosthetic Treatment, “Victor Babeș” University of Medicine and Pharmacy, Revolutiei Ave. 1989, No. 9, 300041 Timişoara, Romania
| | - Luciana Goguță
- Department of Prosthodontics, Faculty of Dental Medicine, “Victor Babes” University of Medicine and Pharmacy, Revolutiei Ave. 1989, No. 9, 300580 Timișoara, Romania
| | - Carmen Opriș
- Department for Materials and Manufacturing Engineering, Faculty of Mechanics, Politechnic University of Timisoara, Mihai Viteazu Ave., No. 1, 300222 Timisoara, Romania
| | - Ioana Ligia Pîrvulescu
- Department of Prosthodontics, Faculty of Dental Medicine, “Victor Babes” University of Medicine and Pharmacy, Revolutiei Ave. 1989, No. 9, 300580 Timișoara, Romania
| | - Liane Avram
- Department of Prosthodontics, Faculty of Dental Medicine, “Victor Babes” University of Medicine and Pharmacy, Revolutiei Ave. 1989, No. 9, 300580 Timișoara, Romania
| | - Andrei Faur
- Department of Prosthodontics, Faculty of Dental Medicine, “Victor Babes” University of Medicine and Pharmacy, Revolutiei Ave. 1989, No. 9, 300580 Timișoara, Romania
| | - Anca Jivănescu
- Department of Prosthodontics, Faculty of Dental Medicine, “Victor Babes” University of Medicine and Pharmacy, Revolutiei Ave. 1989, No. 9, 300580 Timișoara, Romania
- TADERP Research Center—Advanced and Digital Techniques for Endodontic, Restorative and Prosthetic Treatment, “Victor Babeș” University of Medicine and Pharmacy, Revolutiei Ave. 1989, No. 9, 300041 Timişoara, Romania
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14
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Pacquet W, Tapie L, Mawussi B, Boitelle P. Volumetric and dimensional accuracy assessment of CAD-CAM-manufactured dental prostheses from different materials. J Prosthet Dent 2023; 129:150-159. [PMID: 34330531 DOI: 10.1016/j.prosdent.2021.05.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 05/18/2021] [Accepted: 05/18/2021] [Indexed: 01/18/2023]
Abstract
STATEMENT OF PROBLEM In computer-aided design and computer-aided manufacturing (CAD-CAM) dentistry, the CAD of the prosthesis represents the clinical prerequisite design to restore the treated tooth. However, how closely the CAM prosthesis shape matches the CAD, particularly in relation to different materials, is unclear. PURPOSE The purpose of this in vitro study was to evaluate onlays designed and manufactured with the same CAD-CAM system but manufactured with different materials. MATERIAL AND METHODS A single standard tessellation language (STL) model was used to produce 6 composite resin onlays, 6 leucite glass-ceramic onlays, and 6 lithium disilicate glass-ceramic onlays. The onlays were digitized by using an X-ray microtomographic protocol with a metrological calibration. The CAD model was then compared with the scans of the different onlays. An analysis by region of interest was then carried out to assess the accuracy and reliability of the dimensional accuracy. RESULTS The composite resin and the lithium disilicate glass-ceramic had the best dimensional accuracy. The leucite glass-ceramic exhibited a lack of trueness linked to consistent overmilling. The composite resin had less peripheral chipping than the glass-ceramics. CONCLUSIONS The composite resin and the lithium disilicate glass-ceramic material exhibited satisfactory dimensional accuracy. Milling the glass-ceramic before crystallization considerably improved dimensional accuracy.
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Affiliation(s)
- William Pacquet
- Assistant Professor, Oral rehabilitation Department, Faculty of Dentistry, University Lille Nord de France, Paris, France.
| | - Laurent Tapie
- Senior Lecturer, Mechanical engineering Department, University Sorbonne Paris Nord, Paris, France
| | - Bernardin Mawussi
- Professor and Senior Lecturer, Mechanical engineering Department, University Sorbonne Paris Nord, Paris, France
| | - Philippe Boitelle
- Senior Lecturer, Oral rehabilitation Department, Faculty of Dentistry, University Lille Nord de France, Paris, France
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15
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Mancuso E, Mazzitelli C, Maravic T, Pitta J, Mengozzi A, Comba A, Baldi A, Scotti N, Mazzoni A, Fehmer V, Sailer I, Breschi L. The influence of finishing lines and margin location on enamel and dentin removal for indirect partial restorations: A micro-CT quantitative evaluation. J Dent 2022; 127:104334. [PMID: 36257512 DOI: 10.1016/j.jdent.2022.104334] [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: 04/29/2022] [Revised: 10/11/2022] [Accepted: 10/14/2022] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES This in vitro research aimed to quantitatively evaluate the enamel and dentin tissue removal and the residual adhesion surface area (RAS) after different margin designs and locations for indirect partial restorations (IPR). METHODS A human molar was scanned using a Micro-CT and the STL file obtained was used to 3D-print 50 resin-tooth replicas. IPR standardized preparations were performed. The specimens were randomly assigned to 5 groups (n = 10), according to preparation and margin location to the dental equator (DE): 1) Rounded shoulder above the DE (SA); 2) Hollow chamfer above the DE (CA); 3) Butt joint above the DE (BJ); 4) Rounded shoulder below the DE (SB); 5) Chamfer below the DE (CB). Then, the tooth replicas were scanned and each STL file was aligned and superimposed to the original STL model file. Data of enamel and dentin volume removal and RAS were assessed and statistically analyzed (one-way ANOVA and Kruskal-Wallis tests for the two dental substrates respectively). Significance was set at p<0.05. RESULTS Differences in dental tissue reductions were related to the margin location. Above the equator, SA, CA, and BJ performed comparably (p>0.05). Below the equator, CB was significantly more conservative in enamel reduction than SB (p<0.05) and showed the highest enamel adhesive surface exposure among the tested preparations (p<0.05). CONCLUSIONS When the preparation margin is placed above DE, BJ determines a greater exposure of dentin, reducing the adhesive surface in enamel. Below DE, SB seems to be more aggressive in terms of tissue removal compared to CB. CLINICAL SIGNIFICANCE The results of this in vitro study suggest that in teeth requiring partial restoration with the margin below the dental equator, a chamfer preparation would be more conservative than a shoulder preparation. When above the equator, preparations with flat designs would expose more dentine providing a worse substrate for adhesion.
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Affiliation(s)
- Edoardo Mancuso
- Department of Biomedical and Neuromotor Science (DIBINEM), Alma Mater University of Bologna, via S. Vitale 59, 40125 Bologna, Italy
| | - Claudia Mazzitelli
- Department of Biomedical and Neuromotor Science (DIBINEM), Alma Mater University of Bologna, via S. Vitale 59, 40125 Bologna, Italy
| | - Tatjana Maravic
- Department of Biomedical and Neuromotor Science (DIBINEM), Alma Mater University of Bologna, via S. Vitale 59, 40125 Bologna, Italy
| | - João Pitta
- Division of Fixed Prosthodontics and Biomaterials, University Clinics for Dental Medicine, University of Geneva, Geneva, Switzerland
| | - Alessandro Mengozzi
- Department of Biomedical and Neuromotor Science (DIBINEM), Alma Mater University of Bologna, via S. Vitale 59, 40125 Bologna, Italy
| | - Allegra Comba
- Department of Surgical Sciences, Dental School Lingotto, University of Turin, Via Nizza 230, 10126 Turin, Italy
| | - Andrea Baldi
- Department of Surgical Sciences, Dental School Lingotto, University of Turin, Via Nizza 230, 10126 Turin, Italy
| | - Nicola Scotti
- Department of Surgical Sciences, Dental School Lingotto, University of Turin, Via Nizza 230, 10126 Turin, Italy
| | - Annalisa Mazzoni
- Department of Biomedical and Neuromotor Science (DIBINEM), Alma Mater University of Bologna, via S. Vitale 59, 40125 Bologna, Italy
| | - Vincent Fehmer
- Division of Fixed Prosthodontics and Biomaterials, University Clinics for Dental Medicine, University of Geneva, Geneva, Switzerland
| | - Irena Sailer
- Division of Fixed Prosthodontics and Biomaterials, University Clinics for Dental Medicine, University of Geneva, Geneva, Switzerland
| | - Lorenzo Breschi
- Department of Biomedical and Neuromotor Science (DIBINEM), Alma Mater University of Bologna, via S. Vitale 59, 40125 Bologna, Italy.
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16
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Mannocci F, Bitter K, Sauro S, Ferrari P, Austin R, Bhuva B. Present status and future directions: The restoration of root filled teeth. Int Endod J 2022; 55 Suppl 4:1059-1084. [PMID: 35808836 PMCID: PMC9796050 DOI: 10.1111/iej.13796] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 12/30/2022]
Abstract
This narrative review will focus on a number of contemporary considerations relating to the restoration of root filled teeth and future directions for research. Clinicians are now more than ever, aware of the interdependence of the endodontic and restorative aspects of managing root filled teeth, and how these aspects of treatment are fundamental to obtaining the best long-term survival. To obtain the optimal outcomes for patients, clinicians carrying out endodontic treatment should have a vested interest in the restorative phase of the treatment process, as well as an appreciation for the structural and biomechanical effects of endodontic-restorative procedures on restoration and tooth longevity. Furthermore, the currently available research, largely lacks appreciation of occlusal factors in the longevity of root filled teeth, despite surrogate outcomes demonstrating the considerable influence this variable has. Controversies regarding the clinical relevance of minimally invasive endodontic and restorative concepts are largely unanswered with respect to clinical data, and it is therefore, all too easy to dismiss these ideas due to the lack of scientific evidence. However, conceptually, minimally invasive endodontic-restorative philosophies appear to be valid, and therefore, in the pursuit of improved clinical outcomes, it is important that the efficacies of these treatment protocols are determined. Alongside an increased awareness of the preservation of tooth structure, developments in adhesive bonding, ceramic materials and the inevitable integration of digital dentistry, there is also a need to evaluate the efficacy of new treatment philosophies and techniques with well-designed prospective clinical studies.
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Affiliation(s)
- Francesco Mannocci
- Department of EndodonticsFaculty of Dentistry, Oral and Craniofacial SciencesKing's College LondonLondonUK
| | - Kerstin Bitter
- Department of Operative and Preventive DentistryCharité ‐ University Medicine BerlinBerlinGermany
| | - Salvatore Sauro
- Departamento de Odontología, Facultad de Ciencias de la SaludUniversidad CEU‐Cardenal Herrera ValenciaAlfara del PatriarcaSpain
| | - Paolo Ferrari
- Department of Operative DentistryUniversity of ParmaParmaItaly
| | - Rupert Austin
- Department of ProsthodonticsFaculty of Dentistry, Oral and Craniofacial SciencesKing's College LondonLondonUK
| | - Bhavin Bhuva
- Department of EndodonticsFaculty of Dentistry, Oral and Craniofacial SciencesKing's College LondonLondonUK
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17
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Sirous S, Navadeh A, Ebrahimgol S, Atri F. Effect of preparation design on marginal adaptation and fracture strength of ceramic occlusal veneers: A systematic review. Clin Exp Dent Res 2022; 8:1391-1403. [PMID: 36062841 PMCID: PMC9760166 DOI: 10.1002/cre2.653] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 08/13/2022] [Accepted: 08/18/2022] [Indexed: 01/26/2023] Open
Abstract
OBJECTIVES This systematic review aims to investigate the effect of different preparation designs on the marginal fit and fracture strength of ceramic occlusal veneers. MATERIALS AND METHODS Based on the PICO question and the search terms, an electronic search was performed in Google Scholar, PubMed (MEDLINE), Scopus, Cochrane Library, Web of Science, Science Direct, Wiley, Ovid, and SAGE for articles published up to July 2022. After including English in vitro studies that evaluated posterior ceramic occlusal overlays at the posterior with ceramic restorations by following the PRISMA statement, the extracted data was tabulated. The methodological quality of the included studies was evaluated. Risk of bias assessment was done independently by two authors using the modified MINORS scale. RESULTS About 3138 search results were screened, of which 22 were selected due to their titles. Twenty-one full-text articles were assessed for eligibility. Seventeen in-vitro studies were finalized for the extraction of quantitative data. All 17 articles had a low risk of bias and were retained. The influencing items for evaluating the research were different in most studies; therefore, qualitative synthesis of the results was feasible. They generally included preparation design, material thickness, depth of preparation in the tooth, internal divergence angle, and finish line. Meta-analysis was not done due to heterogeneity of preparation types and evaluation methods. Results revealed that fracture resistance of occlusal veneers is higher than normal mastication force, and it is sufficient to prepare the occlusal surface, use a self-etching primer for bonding, and an acceptable minimum ceramic thickness. The marginal discrepancy of occlusal veneers is clinically acceptable. However, this systematic review faces some limitations due to the lack of in vivo studies, different preparation designs in included studies, different follow-ups, and lack of comprehensive explanations in articles. CONCLUSIONS The preparation design of occlusal veneers influences both marginal adaptation and fracture resistance. Various preparation designs are proven to have clinically acceptable fracture strength and marginal adaptation.
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Affiliation(s)
- Samin Sirous
- Departement of Prosthodontics, School of DentistryIslamic Azad University (Khorasgan Branch)IsfahanIran
| | | | - Saeedeh Ebrahimgol
- Department of Prosthodontics, School of DentistryTehran University of Medical SciencesTehranIran
| | - Faezeh Atri
- Department of Prosthodontics, Dental Research CenterDentistry Research Institute, Tehran University of Medical SciencesTehranIran
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18
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Elbadawy AA, Omar EA, AbdElaziz MH. MicroCT evaluation for CAD/CAM occlusal veneer fit using two materials and three cement space settings. Braz Dent J 2022; 33:71-78. [PMID: 36043571 PMCID: PMC9645188 DOI: 10.1590/0103-6440202204764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 04/20/2022] [Indexed: 11/24/2022] Open
Abstract
This study was aimed to evaluate the fit of occlusal veneer restoration for two
CAD/CAM materials with different cement space settings, using microCT scans.
Sixty resin dies were made and divided into two groups (n=30) according to the
materials, (I): Hybrid all-ceramic, and (II): zirconia-reinforced lithium
silicate glass-ceramic. Each group was subdivided into three subgroups (n=10)
according to the cement space parameters (30, 40, and 50 µm). Occlusal veneers
for the six subgroups were milled. A circle with 20 different sections was
placed at the center of every scanned specimen to measure four different
locations (Occlusal, Axial, Marginal, and Absolute marginal discrepancy). Data
were analyzed using two-way ANOVA at a 0.05 level of significance. There was no
statistically significant effect of material type on the mean values of internal
and marginal gaps for the three cement space parameters (P>0.05). There were
no statistically significant differences in the occlusal and axial gap between
the cement space parameters, furthermore, there were statistically significant
differences in marginal gap distances and absolute marginal discrepancies
(P>0.05). Hybrid all-ceramic showed smaller marginal and internal
discrepancies than zirconia-reinforced lithium silicate glass-ceramic without
statistically significant differences, and, for both materials, 50 µm cement
space significantly improved the marginal fit and absolute marginal
discrepancy.
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Affiliation(s)
| | - Elsayed Ali Omar
- Department of Prosthodontics, College of dentistry, Taif University. Al Hawiyah, Saudi Arabia
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Gierthmuehlen PC, Jerg A, Fischer JB, Bonfante EA, Spitznagel FA. Posterior minimally invasive full-veneers: Effect of ceramic thicknesses, bonding substrate, and preparation designs on failure-load and -mode after fatigue. J ESTHET RESTOR DENT 2022; 34:145-153. [PMID: 34989466 DOI: 10.1111/jerd.12861] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/26/2021] [Accepted: 12/17/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To evaluate the effect of ceramic thicknesses, bonding surface (enamel vs. dentin), and preparation design (box vs. no box) on the fatigue survival and failure load of minimally invasive full-veneer restorations. MATERIALS AND METHODS Human-premolars (n = 60) were divided into five test groups (n = 12). All teeth received full-veneer preparation with the following occlusal/labial thicknesses: standard: 1.5/0.8 mm; thin: 1.0/0.6 mm; ultrathin 0.5/0.4 mm. Preparations for each ceramic thickness were refined in enamel (E-1.0 and E-0.5) or dentin (D-1.5, D-1.0, and D-0.5). Control groups DB-1.5, EB-1.0, and EB-0.5 received box preparations. Monolithic lithium disilicate restorations (IPS-e.max-Press, Ivoclar Vivadent) were adhesively cemented (Syntac-Classic/Variolink-II, Ivoclar Vivadent) and subjected to cyclic mechanical loading (F = 49 N, 1.2 million cycles) with simultaneous thermocycling (5-55°C). All specimens were exposed to single load-to-failure. Pair-wise differences were calculated by using a linear regression model and Student-Newman-Keuls method (p < 0.05). RESULTS All full-veneers of group D-1.5, E-1.0, E-0.5, DB-1.5, EB-1.0, and EB-0.5 survived fatigue. Two full-veneers (D-1.0 and D-0.5) revealed cracks during fatigue, resulting in an overall fatigue survival rate of 98.1%. Mean load-to-failure values (N) were as followed: 1005 (D-1.5); 866 (D-1.0); 816 (D-0.5); 1495 (E-1.0); 1279 (E-0.5); 1129 (DB-1.5); 1087 (EB-1.0); and 833 (EB-0.5). Irrespective of ceramic thicknesses, enamel-based full-veneers resulted in higher failure loads than dentin-based restorations. Box preparation reduced the failure loads of thin and ultrathin enamel-based restorations. CONCLUSION All tested monolithic lithium disilicate full-veneer restorations exceeded physiological masticatory forces. Minimally invasive full-veneer restorations with enamel as a bonding surface and a non-retentive preparation design showed superior performance. CLINICAL SIGNIFICANCE Enamel-based non-retentive full-veneers made of monolithic lithium disilicate may serve as a reliable and esthetical minimally invasive treatment option for premolars.
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Affiliation(s)
- Petra C Gierthmuehlen
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
| | - Annika Jerg
- 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, Brazil
| | - Frank A Spitznagel
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
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Rehm P, Derks H, Lesaar W, Spies BC, Beuer F, Böse MWH. Restoration of 1325 teeth with partial-coverage crowns manufactured from high noble metal alloys: a retrospective case series 18.8 years after prosthetic delivery. Clin Oral Investig 2022; 26:849-861. [PMID: 34241707 PMCID: PMC8791919 DOI: 10.1007/s00784-021-04063-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/29/2021] [Indexed: 12/04/2022]
Abstract
OBJECTIVES To evaluate long-term survival and success rates of conventionally cemented partial-coverage crowns (PCCs) manufactured from high noble metal alloys (hn). MATERIAL AND METHODS Restoration-, periodontal- and tooth-related criteria on patients, restored with a single or multiple conventionally cemented hnPCCs in a private dental office were collected from existing patient records. With regard to semi-annual follow-ups, data of the most recent clinical evaluations were considered. Kaplan-Meier and log-rank tests were used for statistical analyses. Level of significance was set at p ≤ .05. RESULTS Between 09/1983 and 09/2009, 1325 hnPCCs were conventionally cemented on 1325 teeth in 266 patients (mean age: 44.5 ± 10.7 years). Due to various reasons, 81 hnPCCs showed complications, documenting a success rate of 93.9% after a mean observation period of 18.8 ± 5.7 years. Of these, additional 14 restorations were counted as survival, resulting in a survival rate of 94.9%. Most frequent complications were periodontal issues (n = 29, 35.8%). Significantly higher success rates were documented for hnPCCs of patients aged between 37 and 51 years (p = .012). CONCLUSION Partial-coverage crowns from high noble metal alloys showed excellent survival and success rates after a mean observation period of 18.8 ± 5.7 years. Higher patient age was one of the risk factors. CLINICAL RELEVANCE According to the results of this study, hnPCCs still represent an excellent therapeutic option-even in modern dentistry.
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Affiliation(s)
- Philipp Rehm
- Private Dental Office Dr. Rehm, Klückenhofstraße 1, 46459, Rees, Germany.
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Aßmannshauser Str. 4-6, Berlin, Germany.
| | - Hermann Derks
- Private Dental Office Dr. Hermann Derks, Steinstraße 12, 46446, Emmerich am Rhein, Germany
| | - Wilfried Lesaar
- Private Dental Office Dr. Hermann Derks, Steinstraße 12, 46446, Emmerich am Rhein, Germany
| | - Benedikt Christopher Spies
- Center for Dental Medicine, Department of Prosthetic Dentistry, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany
| | - Florian Beuer
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Aßmannshauser Str. 4-6, Berlin, Germany
| | - Mats Wernfried Heinrich Böse
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Aßmannshauser Str. 4-6, Berlin, Germany
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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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Al-Zordk W, Saudi A, Abdelkader A, Taher M, Ghazy M. Fracture Resistance and Failure Mode of Mandibular Molar Restored by Occlusal Veneer: Effect of Material Type and Dental Bonding Surface. MATERIALS 2021; 14:ma14216476. [PMID: 34772003 PMCID: PMC8585144 DOI: 10.3390/ma14216476] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/21/2021] [Accepted: 10/26/2021] [Indexed: 11/16/2022]
Abstract
This study assesses the effect of the material type (lithium disilicate, zirconia, and polymer-infiltrated ceramic) and dental bonding substrates (dentin, dentin with intra-coronal cavity, and dentin with composite filling) on the fracture resistance and failure mode of molars restored by occlusal veneers. Methods: Ninety occlusal veneers, fabricated from either lithium disilicate, zirconia, or polymer-infiltrated ceramic, were adhesively bonded to teeth prepared with either dentin, dentin with intra-coronal cavity, or dentin with composite filling. All specimens were thermally aged (5000 cycles), then load cycled (120,000 cycles). Each specimen was subjected to a compressive load through fracture, then was examined (×20) to identify the fracture type. Data were statistically analyzed. Results: Material type and dental substrate had no significant effect on the fracture resistance of adhesively retained occlusal veneer restorations. For each material, no significant differences were found between veneers bonded to dentin, dentin with intra-coronal cavity, and dentin with composite filling. Additionally, within each bonding substrate, there were no significant differences between lithium disilicate, zirconia, and polymer-infiltrated ceramic veneers. The adhesive failure was recorded mainly with zirconia occlusal veneer restorations. Conclusions: Considering the fracture results, lithium disilicate, zirconia, and polymer-infiltrated ceramic occlusal veneers perform well whatever the type of dental bonding surface. When the dental bonding surface varies, different occlusal veneer materials should be considered. Occlusal veneers bonded to dentin, dentin with composite filling, or dentin with an intra-coronal cavity exhibited a fracture resistance exceeding the average human masticatory forces in the molar area.
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Affiliation(s)
- Walid Al-Zordk
- Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Mansoura 35516, Egypt; (A.S.); (A.A.); (M.G.)
- Fixed Prosthodontics Department, Faculty of Dentistry, Horus University, Damietta 34511, Egypt
- Correspondence: ; Tel.: +2-010-0890-6074
| | - Alaa Saudi
- Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Mansoura 35516, Egypt; (A.S.); (A.A.); (M.G.)
| | - Abdelraheem Abdelkader
- Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Mansoura 35516, Egypt; (A.S.); (A.A.); (M.G.)
| | - Mansoura Taher
- Conservative Dentistry Department, Faculty of Dentistry, Mansoura University, Mansoura 35516, Egypt;
| | - Mohamed Ghazy
- Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Mansoura 35516, Egypt; (A.S.); (A.A.); (M.G.)
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Microstructural development during crystallization firing of a dental-grade nanostructured lithia-zirconia glass-ceramic. Ann Ital Chir 2021. [DOI: 10.1016/j.jeurceramsoc.2021.04.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Comparative Stress Evaluation between Bilayer, Monolithic and Cutback All-Ceramic Crown Designs: 3D Finite Element Study. PROSTHESIS 2021. [DOI: 10.3390/prosthesis3020017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Different all-ceramic crown designs are available to perform indirect restoration; however, the mechanical response of each model should still be elucidated. The study aims to evaluate the stress distribution in three different zirconia crown designs using finite element analysis. Different three-dimensional molar crowns were simulated: conventional bilayer zirconia covered with porcelain, a monolithic full-contour zirconia crown, and the cutback modified zirconia crown with porcelain veneered buccal face. The models were imported to the computer-aided engineering (CAE) software. Tetrahedral elements were used to form the mesh and the mechanical properties were assumed as isotropic, linear and homogeneous materials. The contacts were considered ideal. For the static structural mechanical analysis, 100 N occlusal load was applied and the bone tissue was fixed. Maximum principal stress showed that the stress pattern was different for the three crown designs, and the traditional bilayer model showed higher stress magnitude comparing to the other models. However, grayscale stress maps showed homogeneous stress distribution for all models. The all-ceramic crown designs affect the stress distribution, and the cutback porcelain-veneered zirconia crown can be a viable alternative to adequate function and esthetic when the monolithic zirconia crown cannot be indicated.
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Schriwer C, Gjerdet NR, Arola D, Øilo M. The effect of preparation taper on the resistance to fracture of monolithic zirconia crowns. Dent Mater 2021; 37:e427-e434. [PMID: 33910755 DOI: 10.1016/j.dental.2021.03.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/15/2021] [Accepted: 03/28/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Monolithic zirconia crowns have become a viable alternative to conventional layered restorations. The aim of this study was to evaluate whether the taper, and thus wall thickness, of the abutment or pre-defined cement space affect the fracture resistance or fracture mode of monolithic zirconia crowns. METHODS A model tooth was prepared with a taper of 15° and a shallow circumferential chamfer preparation (0.5 mm). Two additional models were made based on the master model with a taper of 10° and 30° using computer-aided design software. Twenty monolithic 3rd generation translucent zirconia crowns were produced for each model with pre-defined cement space set to either 30 μm or 60 μm (n = 60). The estimated cement thickness was assessed by the replica method. The cemented crowns were loaded centrally in the occlusal fossa at 0.5 mm/min until fracture. Fractographic analyses were performed on all fractured crowns. RESULTS The load at fracture was statistically significant different between the groups (p < 0.05). The crowns with 30° taper fractured at lower loads than those with 10° and 15° taper, regardless of the cement space (p < 0.05). The fracture origin for 47/60 crowns (78%) was in the cervical area, close to the top of the curvature in the mesial or distal crown margin. The remaining fractures started at the internal surface of the occlusal area and propagated cervically. SIGNIFICANCE The fracture resistance of the monolithic zirconia crowns was lower for crowns with very large taper compared to 10 and 15° taper even though the crown walls were thicker.
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Affiliation(s)
- Christian Schriwer
- Department of Clinical Dentistry, Faculty of Medicine, University of Bergen, Norway.
| | - Nils Roar Gjerdet
- Department of Clinical Dentistry, Faculty of Medicine, University of Bergen, Norway
| | - Dwayne Arola
- Materials Science and Engineering, University of Washington, USA; Department of Restorative Dentistry, Dental School, University of Washington, USA
| | - Marit Øilo
- Department of Clinical Dentistry, Faculty of Medicine, University of Bergen, Norway
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Wille S, Sieper K, Kern M. Wear resistance of crowns made from different CAM/CAD materials. Dent Mater 2021; 37:e407-e413. [PMID: 33875248 DOI: 10.1016/j.dental.2021.03.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 02/26/2021] [Accepted: 03/29/2021] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The aim of this laboratory study was to evaluate the wear resistance of crowns made from current computer-aided design and computer-aided manufacture (CAD/CAM) materials. In addition, the abrasion of the steatite antagonist against these materials was compared. METHODS Identically shaped crowns of lithium disilicate, zirconia-reinforced lithium disilicate and a polymer-infiltrated ceramic network (PICN) were fabricated with an occlusal thickness of 1.5mm and a lateral wall thickness of 1.2mm (n=8). The crowns were cemented with a dual-polymerizing luting resin on composite resin dies. Using spherical steatite antagonists, all specimens were loaded with 49N for 1,200,000 cycles in a mastication simulator with additional thermocycling. After 120,000, 240,000, 480,000, 960,000, and 1,200,000 cycles, precision impressions were made and investigated with a laser scanning microscope. The vertical and volume substance loss was measured. Additionally, the substance loss of the antagonists was evaluated after 1,200,000 loading cycles. RESULTS No significant difference (p>0.05) was found in the median volume loss of the test materials after 1,200,000 cycles (lithium disilicate: 0.405mm3, PICN: 0.362mm3, zirconia-reinforced lithium disilicate: 0.340mm3). The vertical substance loss of PICN (157μm) was significantly lower (p≤0.05) than that of lithium disilicate (201μm) and zirconia reinforced lithium disilicate (191μm). However, the substance loss of steatite against zirconia-reinforced lithium disilicate (0.191mm3) was significantly lower (p≤0.05) than against lithium disilicate (0.296mm3) and PICN (0.531mm3). SIGNIFICANCE All three CAD/CAM materials showed wear resistance that seems appropriate for clinical application. Also, the abrasion of the antagonist looks promising.
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Affiliation(s)
- Sebastian Wille
- Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University at Kiel, Germany.
| | - Kim Sieper
- Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University at Kiel, Germany.
| | - Matthias Kern
- Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University at Kiel, Germany.
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Gomes de Carvalho AB, de Andrade GS, Mendes Tribst JP, Grassi EDA, Ausiello P, Saavedra GDSFA, Bressane A, Marques de Melo R, Borges ALS. Mechanical Behavior of Different Restorative Materials and Onlay Preparation Designs in Endodontically Treated Molars. MATERIALS 2021; 14:ma14081923. [PMID: 33921347 PMCID: PMC8070423 DOI: 10.3390/ma14081923] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 11/24/2022]
Abstract
This study evaluated the effect of the combination of three different onlay preparation designs and two restorative materials on the stress distribution, using 3D-finite element analysis. Six models of first lower molars were created according to three preparation designs: non-retentive (nRET), traditional with occlusal isthmus reduction (IST), and traditional without occlusal isthmus reduction (wIST); and according to two restorative materials: lithium-disilicate (LD) and nanoceramic resin (NR). A 600 N axial load was applied at the central fossa. All solids were considered isotropic, homogeneous, and linearly elastic. A static linear analysis was performed, and the Maximum Principal Stress (MPS) criteria were used to evaluate the results and compare the stress in MPa on the restoration, cement layer, and tooth structure (enamel and dentin). A novel statistical approach was used for quantitative analysis of the finite element analysis results. On restoration and cement layer, nRET showed a more homogeneous stress distribution, while the highest stress peaks were calculated for LD onlays (restoration: 69–110; cement layer: 10.2–13.3). On the tooth structure, the material had more influence, with better results for LD (27–38). It can be concluded that nRET design showed the best mechanical behavior compared to IST and wIST, with LD being more advantageous for tooth structure and NR for the restoration and cement layer.
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Affiliation(s)
- Ana Beatriz Gomes de Carvalho
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), São José dos Campos 12245-000, Brazil; (A.B.G.d.C.); (G.S.d.A.); (E.D.A.G.); (G.d.S.F.A.S.); (R.M.d.M.); (A.L.S.B.)
| | - Guilherme Schmitt de Andrade
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), São José dos Campos 12245-000, Brazil; (A.B.G.d.C.); (G.S.d.A.); (E.D.A.G.); (G.d.S.F.A.S.); (R.M.d.M.); (A.L.S.B.)
| | - João Paulo Mendes Tribst
- Graduate Program in Dentistry, Department Dentistry, University of Taubate (UNITAU), Taubate 12020-270, Brazil;
| | - Elisa Donária Aboucauch Grassi
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), São José dos Campos 12245-000, Brazil; (A.B.G.d.C.); (G.S.d.A.); (E.D.A.G.); (G.d.S.F.A.S.); (R.M.d.M.); (A.L.S.B.)
| | - Pietro Ausiello
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, School of Dentistry, University of Naples Federico II, 80138 Naples, Italy
- Correspondence:
| | - Guilherme de Siqueira Ferreira Anzaloni Saavedra
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), São José dos Campos 12245-000, Brazil; (A.B.G.d.C.); (G.S.d.A.); (E.D.A.G.); (G.d.S.F.A.S.); (R.M.d.M.); (A.L.S.B.)
| | - Adriano Bressane
- Graduate Oral Health Applied Science, Institute of Science and Technology, São Paulo State University (Unesp), São José dos Campos 12245-000, Brazil;
| | - Renata Marques de Melo
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), São José dos Campos 12245-000, Brazil; (A.B.G.d.C.); (G.S.d.A.); (E.D.A.G.); (G.d.S.F.A.S.); (R.M.d.M.); (A.L.S.B.)
| | - Alexandre Luiz Souto Borges
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), São José dos Campos 12245-000, Brazil; (A.B.G.d.C.); (G.S.d.A.); (E.D.A.G.); (G.d.S.F.A.S.); (R.M.d.M.); (A.L.S.B.)
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Albelasy E, Hamama HH, Tsoi JKH, Mahmoud SH. Influence of material type, thickness and storage on fracture resistance of CAD/CAM occlusal veneers. J Mech Behav Biomed Mater 2021; 119:104485. [PMID: 33812289 DOI: 10.1016/j.jmbbm.2021.104485] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/09/2021] [Accepted: 03/15/2021] [Indexed: 11/16/2022]
Abstract
OBJECTIVES The present study aimed to evaluate the effect of restoration thickness, CAD/CAM material, and 6 months of artificial saliva storage on the fracture resistance of occlusal veneers. MATERIALS AND METHODS A total of 84 intact maxillary molars were sectioned 4.0 mm occlusal to the cementoenamel junction to expose the dentine. The teeth were assigned into 3 main groups according to the type of restorative material (e.max CAD, Vita Enamic, and Lava Ultimate). In each group, the teeth were allocated into 2 subgroups (n = 14) according to restoration thickness (1.0 and 1.5 mm). The veneers were adhesively bonded using dual-cure self-adhesive luting agent. A total of 42 specimens comprising half the tested subgroups were stored in distilled water for 24-h before the test. The remaining half was stored in artificial saliva at 37 ± 1 °C in an incubator for 6 months. All specimens (n = 84) were subjected to 5000 thermal cycles between 5 and 55 °C ± 2 before the fracture resistance test. The maximum force at fracture was recorded in Newton. Failure mode was analyzed using a stereomicroscope. The results were analyzed using a parametric Three-way ANOVA test. RESULTS The results of the Three-way ANOVA test revealed that material type and restoration thickness significantly affected fracture resistance values (p < 0.5), while 6 months of storage in artificial saliva had no significant effect on mean fracture resistance values (p˃0.5). The most common failure patterns in CAD/CAM resin composite and polymer-infiltrated ceramics were scores I and score II. For glass ceramic groups, score IV and III were more dominant. CONCLUSIONS All the tested CAD/CAM restorations in both thicknesses exhibited fracture resistance values exceeding normal and parafunctional bite forces. Polymer-infiltrated ceramics and CAD/CAM resin composite veneers showed more favorable fracture patterns.
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Affiliation(s)
- Eman Albelasy
- Operative Dentistry Department, Faculty of Dentistry, Mansoura University, Egypt
| | - Hamdi H Hamama
- Operative Dentistry Department, Faculty of Dentistry, Mansoura University, Egypt.
| | - James K H Tsoi
- Dental Material Science, Division of Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China
| | - Salah H Mahmoud
- Operative Dentistry Department, Faculty of Dentistry, Mansoura University, Egypt
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Rocca GT, Baldrich B, Saratti CM, Delgado LM, Roig M, Daher R, Krejci I. Restoration's thickness and bonding tooth substrate are determining factors in minimally invasive adhesive dentistry. J Prosthodont Res 2021; 65:407-414. [PMID: 33762503 DOI: 10.2186/jpr.jpr_d_20_00008] [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 To explore fracture strength and failure behaviour of minimally invasive CAD-CAM composite resin overlay restorations.Methods Eighty bi- and tri-layer cylindrical overlay model including the restoration bonded over bovine tooth dentin (Groups D) and enamel-dentin (Groups E) were assembled (diameter 9 mm). Restorations were milled from CAD-CAM composite resin blocks (Brilliant Crios, Coltène/Whaledent AG) in different thicknesses (0.5mm, 1mm, 1.5mm, 2mm) and equally distributed in four Groups D and four Groups E (n=10). All specimens were submitted to an Hertzian load-to-failure contact test with spherical indenter. Critical loads were recorded in Newton and data were analysed using Kruskal-Wallis test for multiple and Mann-Whitney test for 2-samples comparisons (p < 0.05). Fragments were examined using SEM. The stress distribution for specimens with restorations of 0.5 mm and 2 mm was also investigated with FEA.Results For all specimens, the mean static loads in Newton increased with an increase in restoration thickness. On contrary, restorations with the same thickness displayed higher resistance values when bonded over enamel than dentin, except for the 2-mm thick restorations. A damage competition was detected between cone/median cracks originating at the loading contact area of the restorations and radial cracks beginning at their inner surface, with the former prevailing in restorations bonded on enamel and the latter being dominant for restorations bonded on dentin.Conclusions For bonded ultra-thin resin composite restorations (0.5 mm to 1.5 mm) enamel as bonding substrate assures higher critical loads to fracture than dentin. This influence gradually decreases as restoration thickened.
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Affiliation(s)
- Giovanni Tommaso Rocca
- Division of Cariology and Endodontology, School of Dentistry, University of Geneva, Geneva, Switzerland
| | - Borja Baldrich
- Department of Restorative Dentistry, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Carlo Massimo Saratti
- Division of Cariology and Endodontology, School of Dentistry, University of Geneva, Geneva, Switzerland
| | - Luis Maria Delgado
- Bioengineering Institute of Technology, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Miguel Roig
- Department of Restorative Dentistry, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Rene Daher
- Division of Cariology and Endodontology, School of Dentistry, University of Geneva, Geneva, Switzerland
| | - Ivo Krejci
- Division of Cariology and Endodontology, School of Dentistry, University of Geneva, Geneva, Switzerland
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Weng JH, Chen HL, Chen G, Cheng CH, Liu JF. Compressive strength of lithium disilicate inlay cementation on three different composite resins. J Dent Sci 2021; 16:994-1000. [PMID: 34141115 PMCID: PMC8189877 DOI: 10.1016/j.jds.2021.01.008] [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] [Received: 09/06/2020] [Revised: 01/18/2021] [Indexed: 11/24/2022] Open
Abstract
Background/purpose Ceramic restorations have been increasingly applied over recent years. But the performance of cement is still unknown after cementation. This study was aimed to compare the compressive strength and the performances of three different types of composite resin after lithium disilicate inlay cementation. Materials and methods Twenty-four human maxillary premolars were embedded in resin blocks, finished a MOD inlay preparation and scanned with an extraoral scanner. Lithium disilicate ceramic inlays (IPS e.max, Ivoclar Vivadent, Liechtenstein) were fabricated according to the scanner's model. All the specimens were then etched, bonded, and cemented with three different composite resins. Right after 5000 thermal cyclings, the specimens were accepted compressive tests to evaluate the compressive strength and failure types. Moreover, the fracture fragments of the specimens were examined using scanning electron microscopy (SEM) to verify the fracture type. Results Dual-cured resin cement (Rely X Ultimate) showed the highest compressive strength (1002 ± 508 N), followed by the light-cured flowable resin (Z350 XT) (971 ± 209 N) and light-cured bulkfill (Filtek Bulkfill) resin (581 ± 191 N). Type IV (root fracture) failures in the dual-cured resin cement group was 25%, and light-cured flowable resin was 37.5%. But none of type IV fracture was found in the light-cured bulkfill flowable group. Conclusion Dual-cured resin cement demonstrates the highest compressive strength after ceramic inlay cementation. Light-cured bulkfill resin shows the lowest compressive strength, but catastrophic failure is absent in this group.
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Affiliation(s)
- Jui-Hung Weng
- Department of Stomatology, Taichung Veteran General Hospital, Taichung, Taiwan.,School of Dentistry, Chung Shan Medical University, Taichung, Taiwan
| | - Hui-Ling Chen
- Department of Stomatology, Taichung Veteran General Hospital, Taichung, Taiwan.,School of Dentistry, National Yang Ming University, Taipei, Taiwan
| | - Gin Chen
- Department of Stomatology, Taichung Veteran General Hospital, Taichung, Taiwan.,School of Dentistry, Chung Shan Medical University, Taichung, Taiwan
| | - Chung-Hsiao Cheng
- Department of Stomatology, Taichung Veteran General Hospital, Taichung, Taiwan
| | - Jeng-Fen Liu
- Department of Stomatology, Taichung Veteran General Hospital, Taichung, Taiwan.,School of Dentistry, National Yang Ming University, Taipei, Taiwan
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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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de Andrade GS, Pinto ABA, Tribst JPM, Chun EP, Borges ALS, de Siqueira Ferreira Anzaloni Saavedra G. Does overlay preparation design affect polymerization shrinkage stress distribution? A 3D FEA study. Comput Methods Biomech Biomed Engin 2021; 24:1026-1034. [PMID: 33410710 DOI: 10.1080/10255842.2020.1866561] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This study evaluated the polymerization shrinkage stress of three tooth preparation designs for indirect ceramic overlay by finite element analysis: isthmus preparation (IST); without isthmus preparation (wIST); and non-retentive preparation (nRET). The models were created based in prepared dental typodonts and were digitally impressed with an intraoral scanner. The interfaces in all models were considered perfectly bonded and all materials were considered homogeneous, linear, and isotropic. The polymerization shrinkage of the cement layer (100 µm) was simulated and evaluated by maximum principal stress criteria. The stress peaks followed this sequence: restoration = IST (13.4 MPa) > wIST (9.3 MPa) > nRET (9 MPa); cement layer = IST (16.9 MPa) > wIST (12.6 MPa) > nRET (10-7.5 MPa); and teeth = IST (10.7 MPa) > wIST (10.5 MPa) > (9 MPa). For the cement layer, the non-retentive preparation (nRET) had the lowest shrinkage stress from all the groups, obtaining a more homogeneous stress distribution on the cement surface. Regarding the abutment teeth, the IST generated a higher shrinkage stress area on the dental structure, concentrating higher stress magnitude at the axiopulpar and axiogingival angles. Non-retentive preparation seems to reduce polymerization shrinkage stress.
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Affiliation(s)
- Guilherme Schmitt de Andrade
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (UNESP), São José dos Campos, Brazil
| | - Alana Barbosa Alves Pinto
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (UNESP), São José dos Campos, Brazil
| | - João Paulo Mendes Tribst
- Departament of Dentistry, Postgraduate Program in Dentistry, University of Taubaté (UNITAU), Taubaté, Brazil
| | | | - Alexandre Luiz Souto Borges
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (UNESP), São José dos Campos, 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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Maghami E, Pejman R, Najafi AR. Fracture micromechanics of human dentin: A microscale numerical model. J Mech Behav Biomed Mater 2020; 114:104171. [PMID: 33218927 DOI: 10.1016/j.jmbbm.2020.104171] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/17/2020] [Accepted: 10/23/2020] [Indexed: 11/25/2022]
Abstract
In the present study, we investigate the effects of microstructural morphology and heterogeneity on the initiation and propagation of microcracks in dentin. We create 2D pre-cracked models of human dentin at the microscale level and use a brittle fracture framework of the phase-field method to analyze the crack growth. We discuss the influence of the microstructural features on crack deflection, microcracking, and uncracked ligament bridging through various regions in dentin. The results demonstrate that the difference between the critical energy release rates of peritubular (PTD) and intertubular dentin (ITD) has considerable impacts on microcracking. Our simulations reveal that tubules surrounded by PTDs play an important role in the crack deflection. Our results also indicate that the toughness of dentin increases from the inner to outer dentin. In conclusion, the findings in our study provide valuable insights into the fracture behavior in various regions of dentin.
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Affiliation(s)
- Ebrahim Maghami
- Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, 19104, USA
| | - Reza Pejman
- Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, 19104, USA
| | - Ahmad R Najafi
- Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, 19104, USA.
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The influence of the restorative material on the mechanical behavior of screw-retained hybrid-abutment-crowns. J Mech Behav Biomed Mater 2020; 111:103988. [DOI: 10.1016/j.jmbbm.2020.103988] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/07/2020] [Accepted: 07/11/2020] [Indexed: 11/18/2022]
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Malament KA, Margvelashvili-Malament M, Natto ZS, Thompson V, Rekow D, Att W. Comparison of 16.9-year survival of pressed acid etched e.max lithium disilicate glass-ceramic complete and partial coverage restorations in posterior teeth: Performance and outcomes as a function of tooth position, age, sex, and thickness of ceramic material. J Prosthet Dent 2020; 126:533-545. [PMID: 33010922 DOI: 10.1016/j.prosdent.2020.08.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 12/18/2022]
Abstract
STATEMENT OF PROBLEM Long-term clinical data are lacking on the comparison of the survival of adhesively luted pressed e.max lithium disilicate glass-ceramic complete and partial coverage restorations in posterior dentitions and the effect that different technical and clinical variables have on their survival. PURPOSE The purpose of this clinical study was to examine and compare the 16.9-year survival of posterior pressed e.max lithium disilicate glass-ceramic complete and partial coverage restorations and associated clinical parameters on the outcome. MATERIAL AND METHODS Patients requiring either single-unit posterior defect-specific partial coverage or complete coverage restorations were recruited in a clinical private practice. The participants were offered the options of direct restorations, partial coverage cast gold, or glass-ceramic (lithium disilicate) restorations. Those requiring complete coverage restorations were given the options of complete cast gold, metal-ceramic, or glass-ceramic restorations. Only participants who chose glass-ceramic partial and complete coverage restorations were included in the study. The overall survival of the glass-ceramic restorations was assessed by the clinical factors determined at recall. The effect of various clinical parameters (type of restoration, dental arch, tooth position in the dental arch, age and sex of participant, and ceramic thickness) was evaluated by using Kaplan-Meier survival curves to account for attrition bias and other reasons for failure. The statistical significance of differences between parameters was determined using the log rank test (α=.05). RESULTS A total of 738 participants requiring 2392 lithium disilicate restorations in posterior teeth were evaluated. The mean age of the participants at the time of restoration placement was 62 (range: 20-99 years, 302 men and 436 women). Of 2392 units, 1782 were complete and 610 were partial coverage restorations. A total of 22 failures (bulk fracture or large chip) requiring replacement were recorded with the average time to failure 3.5 (0.02-7.9) years. The total time at risk computed for these units was 13227.9 years, providing an estimated failure risk of 0.17% per year. The 16.9-year estimated cumulative survival was 96.49%. The estimated cumulative survival of posterior complete (n=1782) and posterior partial coverage restorations (n=610) was 96.75% at 10.5 years and 95.27% at 16.9 years (P<.05). Of the 22, 16 failures were recorded for the complete coverage restorations. The total time at risk for these restorations was 10144.5 years, providing an estimated risk of 0.16 per year. The other 6 failures recorded occurred for the partial coverage restorations. The total time at risk for these restorations was 3083.5 years, providing an estimated risk of 0.19% per year. No statistically significant difference was found in the survival of posterior complete and partial coverage restorations among men and women, different age groups, or posterior tooth position in the dental arch (P>.05). The thickness of the restoration also had no influence on the survival of glass-ceramic posterior restorations (P>.05). CONCLUSIONS Pressed e.max lithium disilicate complete and partial coverage restorations showed high survival rates in posterior teeth over a 16.9-year period, with an overall failure rate of 0.17% per year. Risk of failure at any age was low for both men and women. No statistically significant difference was found in the survival of complete and partial coverage restorations, and none of the confounding variables, including the thickness of the restoration, appeared to have a significant effect on survival.
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Affiliation(s)
- Kenneth A Malament
- Clinical Professor, Department of Prosthodontics, Tufts University School of Dental Medicine, Boston, Mass.
| | | | - Zuhair S Natto
- Assistant Professor, Department of Dental Public Health, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia; Adjunct Assistant Professor, Department of Periodontology, Tufts University School of Dental Medicine, Boston, Mass
| | - Van Thompson
- Professor Emeritus, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London, UK
| | - Dianne Rekow
- Professor Emeritus, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London, UK
| | - Wael Att
- Professor and Chair, Department of Prosthodontics, Tufts University School of Dental Medicine, Boston, Mass
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Albelasy EH, Hamama HH, Tsoi JK, Mahmoud SH. Fracture resistance of CAD/CAM occlusal veneers: A systematic review of laboratory studies. J Mech Behav Biomed Mater 2020; 110:103948. [DOI: 10.1016/j.jmbbm.2020.103948] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/18/2020] [Accepted: 06/21/2020] [Indexed: 11/27/2022]
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Souza J, Fuentes MV, Baena E, Ceballos L. One-year clinical performance of lithium disilicate versus resin composite CAD/CAM onlays. Odontology 2020; 109:259-270. [PMID: 32705420 PMCID: PMC7790784 DOI: 10.1007/s10266-020-00539-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 07/09/2020] [Indexed: 11/28/2022]
Abstract
To compare the 1-year clinical performance of lithium disilicate and resin composite CAD/CAM onlay restorations. Twenty patients that required two restorations in posterior teeth, with at least one cusp to be covered, received two onlays. One was made with IPS e.max CAD (Ivoclar-Vivadent) and the other with Lava Ultimate (3M Oral Care). Two blind observers evaluated the restorations at baseline and 1 year after the onlays were cemented, according to FDI criteria. At each recall, digital photographs, bite-wing radiographs and impressions of the restorations were taken for SEM evaluation of the interface. Results were analyzed by Mann–Whitney U and Wilcoxon tests (p < 0.05). At baseline and in the 1-year recall, both CAD/CAM materials exhibited excellent results in most criteria with similar esthetic, functional and biological properties (p > 0.05). However, deterioration in surface lustre (p = 0.020) and color match/translucency (p = 0.039) were detected for IPS e.max CAD onlays after 1-year. Under SEM evaluation, there were no statistically differences in micromorphological criteria at baseline nor after a year between IPS e.max CAD and Lava Ultimate onlays. Conclusion: After 1 year of clinical service IPS e.max CAD and Lava Ultimate onlays showed a similar clinical performance that needs to be confirmed in long-term evaluations.
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Affiliation(s)
- Joana Souza
- Area of Stomatology, IDIBO Research Group, Health Sciences Faculty, Rey Juan Carlos University, Avenida de Atenas s/n, 28922, Alcorcón, Madrid, Spain
| | - Mª Victoria Fuentes
- Area of Stomatology, IDIBO Research Group, Health Sciences Faculty, Rey Juan Carlos University, Avenida de Atenas s/n, 28922, Alcorcón, Madrid, Spain
| | - Eugenia Baena
- Area of Stomatology, IDIBO Research Group, Health Sciences Faculty, Rey Juan Carlos University, Avenida de Atenas s/n, 28922, Alcorcón, Madrid, Spain
| | - Laura Ceballos
- Area of Stomatology, IDIBO Research Group, Health Sciences Faculty, Rey Juan Carlos University, Avenida de Atenas s/n, 28922, Alcorcón, Madrid, Spain.
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Zhang X, Li T, Wang X, Yang L, Wu J. Glass-ceramic resin-bonded fixed partial dentures for replacing a single premolar tooth: A prospective investigation with a 4-year follow-up. J Prosthet Dent 2020; 124:53-59. [PMID: 31735350 DOI: 10.1016/j.prosdent.2019.07.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/01/2019] [Accepted: 07/01/2019] [Indexed: 11/30/2022]
Abstract
STATEMENT OF PROBLEM Resin-bonded fixed partial dentures (RBFPDs) are a reliable treatment option for the replacement of a single missing tooth. Glass-ceramic may be a promising material for the fabrication of RBFPDs, but clinical verification has been lacking. PURPOSE The purpose of this prospective clinical study was to evaluate the outcomes of glass-ceramic RBFPDs on participants with a single missing premolar. MATERIAL AND METHODS Twenty participants (6 men, 14 women; age range: 20 to 54 years) were treated with 2-retainer RBFPDs. These RBFPDs were made of lithium disilicate glass-ceramic (IPS e.max Press; Ivoclar Vivadent AG) and designed with improved C-shaped retention. These prostheses were evaluated at 6 months, 12 months, and annually thereafter and were classified as survival or failure. Analysis was performed with the Kaplan-Meier analysis (95% confidence interval). Modified United States Public Health Service (USPHS) criteria were used to rate the clinical performance. Parameters assessed were fracture, marginal integrity, marginal discoloration, color of restoration, secondary caries, and abutment mobility. RESULTS Twenty RBFPDs were provided, 9 in the maxilla and 11 in the mandible. The mean observation time was 49.2 months (minimum 9 months, maximum 53 months). Nineteen RBFPDs were evaluated as having survived during the observation period with some acceptable marginal discoloration, 1 RBFPD had to be replaced because of fracture and secondary caries and was evaluated as a failure. The Kaplan-Meier analysis revealed a survival rate of 95% after a 4-year observation. CONCLUSIONS The glass-ceramic RBFPDs in this study displayed a good survival rate and clinical performance, indicating that glass-ceramic RBFPDs might be a promising approach for the short-term replacement of a single premolar. However, further investigations are needed to determine the long-term outcome.
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Affiliation(s)
- Xinyan Zhang
- Graduate student, Graduate Prosthodontics, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Department of Prosthodontics, School of Stomatology, Shandong University, Jinan, PR China
| | - Tong Li
- Associate Professor, Department of Endodontics, Jinan Stomatological Hospital, Jinan, PR China
| | - Xiaoxi Wang
- Graduate student, Graduate Prosthodontics, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Department of Prosthodontics, School of Stomatology, Shandong University, Jinan, PR China
| | - Lili Yang
- Graduate student, Graduate Prosthodontics, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Department of Prosthodontics, School of Stomatology, Shandong University, Jinan, PR China
| | - Junling Wu
- Associate Professor, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Department of Prosthodontics, School of Stomatology, Shandong University, Jinan, PR China.
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Falahchai M, Babaee Hemmati Y, Neshandar Asli H, Rezaei E. Effect of Tooth Preparation Design on Fracture Resistance of Zirconia‐Reinforced Lithium Silicate Overlays. J Prosthodont 2020; 29:617-622. [DOI: 10.1111/jopr.13160] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2020] [Indexed: 11/28/2022] Open
Affiliation(s)
- Mehran Falahchai
- Dental Sciences Research Center, Department of Prosthodontics, School of DentistryGuilan University of Medical Sciences Rasht Iran
| | - Yasamin Babaee Hemmati
- Dental Sciences Research Center, Department of Orthodontics, School of DentistryGuilan University of Medical Sciences Rasht Iran
| | - Hamid Neshandar Asli
- Dental Sciences Research Center, Department of Prosthodontics, School of DentistryGuilan University of Medical Sciences Rasht Iran
| | - Elnaz Rezaei
- Dental Sciences Research Center, Department of Prosthodontics, School of DentistryGuilan University of Medical Sciences Rasht Iran
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Huang X, Zou L, Yao R, Wu S, Li Y. Effect of preparation design on the fracture behavior of ceramic occlusal veneers in maxillary premolars. J Dent 2020; 97:103346. [PMID: 32325176 DOI: 10.1016/j.jdent.2020.103346] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/27/2020] [Accepted: 04/15/2020] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES The fracture strengths of four types of occlusal veneers and a traditional full crown ceramic restoration and the influence of preparation design on the stress of restorations were examined. METHODS Forty intact maxillary premolars randomly divided into five groups were prepared based on the demands of type O (occlusal surface coverage), OF (occlusal and lingual surface coverage), POF (occlusal, lingual, and mesial surface coverage), and POFP (occlusal, lingual, mesial, and distal surface coverage) veneers and full crown, and then restored by glass ceramic. Specimens were subjected to fracture resistance tests after cyclic loading. The fracture strengths and modes were analyzed statistically. The level of significance was set at α = 0.05. One maxillary premolar was prepared for type O, OF, POF, POFP veneer and full crown, and then scanned to establish finite element models. The mean fracture load was applied vertically to calculate the maximum principal stress on the ceramic. RESULTS Type O veneer showed higher fracture strength than type POF and POFP veneers (P < 0.05). Both type O and OF veneers exhibited higher fracture strength than full crown (P < 0.05). No significant difference in failure mode was observed. The maximum principal stress for type O, OF, POF, POFP veneers, and full crown increased progressively and concentrated at the bonding surface directly beneath the loading area. CONCLUSIONS Four types of occlusal veneer showed fracture strengths that considerably exceeded normal biting forces. They represent conservative alternatives to full crowns and present a viable treatment for severely worn teeth. CLINICAL SIGNIFICANCE The occlusal veneers with different preparation designs, including type O, OF, POF and POFP veneers, show higher fracture resistances than traditional full coverage crowns that considerably exceed the normal biting forces. Therefore, these represent conservative alternatives to crown restorations and present a viable treatment for restoring severely worn teeth.
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Affiliation(s)
- Xiaoqiong Huang
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, People's Republic of China.
| | - Leiyan Zou
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, People's Republic of China.
| | - Run Yao
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Shuyi Wu
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, People's Republic of China.
| | - Yan Li
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, People's Republic of China.
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García-Engra G, Fernandez-Estevan L, Casas-Terrón J, Fons-Font A, Castelo-Baz P, Agustín-Panadero R, Román-Rodriguez JL. Fracture Resistance of New Metal-Free Materials Used for CAD-CAM Fabrication of Partial Posterior Restorations. Medicina (B Aires) 2020; 56:medicina56030132. [PMID: 32197479 PMCID: PMC7143083 DOI: 10.3390/medicina56030132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/14/2020] [Accepted: 03/16/2020] [Indexed: 11/24/2022] Open
Abstract
Background and Objectives: To evaluate in vitro the fracture resistance and fracture type of computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: Discs were fabricated (10 × 1.5 mm) from four test groups (N = 80; N = 20 per group): lithium disilicate (LDS) group (control group): IPS e.max CAD®; zirconium-reinforced lithium silicate (ZRLS) group: VITA SUPRINITY®; polymer-infiltrated ceramic networks (PICN) group: VITA ENAMIC®; resin nanoceramics (RNC) group: LAVA™ ULTIMATE. Each disc was cemented (following the manufacturers’ instructions) onto previously prepared molar dentin. Samples underwent until fracture using a Shimadzu® test machine. The stress suffered by each material was calculated with the Hertzian model, and its behavior was analyzed using the Weibull modulus. Data were analyzed with ANOVA parametric statistical tests. Results: The LDS group obtained higher fracture resistance (4588.6 MPa), followed by the ZRLS group (4476.3 MPa) and PICN group (4014.2 MPa) without statistically significant differences (p < 0.05). Hybrid materials presented lower strength than ceramic materials, the RNC group obtaining the lowest values (3110 MPa) with significant difference (p < 0.001). Groups PICN and RNC showed greater occlusal wear on the restoration surface prior to star-shaped fracture on the surface, while other materials presented radial fracture patterns. Conclusion: The strength of CAD-CAM materials depended on their composition, lithium disilicate being stronger than hybrid materials.
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Affiliation(s)
- Georgina García-Engra
- Prosthodontics and Occlusion Unit, Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, 46021 Valencia, Spain; (G.G.-E.); (J.C.-T.); (A.F.-F.); (R.A.-P.); (J.L.R.-R.)
| | - Lucia Fernandez-Estevan
- Prosthodontics and Occlusion Unit, Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, 46021 Valencia, Spain; (G.G.-E.); (J.C.-T.); (A.F.-F.); (R.A.-P.); (J.L.R.-R.)
- Correspondence: ; Tel.: +34-963-864-034
| | - Javier Casas-Terrón
- Prosthodontics and Occlusion Unit, Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, 46021 Valencia, Spain; (G.G.-E.); (J.C.-T.); (A.F.-F.); (R.A.-P.); (J.L.R.-R.)
| | - Antonio Fons-Font
- Prosthodontics and Occlusion Unit, Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, 46021 Valencia, Spain; (G.G.-E.); (J.C.-T.); (A.F.-F.); (R.A.-P.); (J.L.R.-R.)
| | - Pablo Castelo-Baz
- Co-director of Master’s Program in Endodontics, Restorative Dentistry, and Dental Esthetics, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain;
| | - Rubén Agustín-Panadero
- Prosthodontics and Occlusion Unit, Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, 46021 Valencia, Spain; (G.G.-E.); (J.C.-T.); (A.F.-F.); (R.A.-P.); (J.L.R.-R.)
| | - Juan Luis Román-Rodriguez
- Prosthodontics and Occlusion Unit, Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, 46021 Valencia, Spain; (G.G.-E.); (J.C.-T.); (A.F.-F.); (R.A.-P.); (J.L.R.-R.)
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Tribst JP, Kohn BM, de Oliveira Dal Piva AM, Spinola MS, Borges AL, Andreatta Filho OD. Influence of restoration thickness on the stress distribution of ultrathin ceramic onlay rehabilitating canine guidance: a 3D-finite element analysis. ACTA ACUST UNITED AC 2019; 68:126-131. [PMID: 31014062 DOI: 10.23736/s0026-4970.19.04183-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The rehabilitation of canine guidance can be performed with adhesive indirect materials, but can the restoration thickness be reduced without mechanical disadvantages? Thus the goal of this study was to analyze the stress of upper canines which received different thicknesses of ceramic fragments for the rehabilitation of the canine guidance using finite element analysis. METHODS A superior canine was modeled using a computer aided design software. The dental tissues were individually shaped containing enamel, dentin and periodontal ligament. The following three different ceramic fragment thicknesses were then implemented: 0.3, 0.7 and 1.5 mm. Lithium disilicate was chosen as the ceramic material. The solid geometries were exported to the analysis software. The materials were considered isotropic, homogeneous and linear. The set was submitted to efforts in the incisal third in the palatine face to analyze maximal principal stress, mimicking mandibular lateral movement. The applied load was 100N, and the fixation region was on the medullary bone. RESULTS For restoration, the thinner the ceramic, the higher the stress concentration was; while for the adhesive surface of teeth, the thicker the ceramic, the higher the stress concentration. CONCLUSIONS The smaller the ceramic thickness was, the lower stress concentration showed at the adhesive interface, while the stress concentration was higher on the restoration intaglio surface.
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Affiliation(s)
- João P Tribst
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University, Unesp, São José dos Campos, SP, Brazil
| | - Bianca M Kohn
- Institute of Science and Technology, São Paulo State University, Unesp, São José dos Campos, SP, Brazil
| | - Amanda M de Oliveira Dal Piva
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University, Unesp, São José dos Campos, SP, Brazil -
| | - Manuela S Spinola
- Department of Restorative Dentistry, Institute of Science and Technology, São Paulo State University, Unesp, São José dos Campos, SP, Brazil
| | - Alexandre L Borges
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University, Unesp, São José dos Campos, SP, Brazil
| | - Osvaldo D Andreatta Filho
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University, Unesp, São José dos Campos, SP, Brazil
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Savi A, Crescini A, Manfredi M, De Maria A, Bresciano M. Agenesis of a maxillary lateral incisor associated with bilateral canine inclusions: A noninvasive multidisciplinary approach. J ESTHET RESTOR DENT 2019; 31:542-552. [DOI: 10.1111/jerd.12515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 05/17/2019] [Accepted: 07/07/2019] [Indexed: 11/26/2022]
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Chen SE, Park AC, Wang J, Knoernschild KL, Campbell S, Yang B. Fracture Resistance of Various Thickness e.max CAD Lithium Disilicate Crowns Cemented on Different Supporting Substrates: An In Vitro Study. J Prosthodont 2019; 28:997-1004. [PMID: 31469479 DOI: 10.1111/jopr.13108] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2019] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To investigate the influence of abutment material properties on the fracture resistance and failure mode of lithium disilicate (IPS e.max) CAD/CAM (computer-aided design/manufacturing) crowns on traditionally and minimally prepared simulated tooth substrates. MATERIALS AND METHODS Thirty lithium disilicate (IPS e.max) CAD/CAM crowns were divided into three groups (n = 10): TD: traditional thickness crowns cemented on Paradigm MZ100 abutments; MD: minimal thickness crowns cemented on Paradigm MZ100 abutments; ME: minimal thickness crowns cemented on e.max abutments. The 3Shape system was used to scan, design and mill all abutments and crowns with a die space set to 40 µm. Traditional thickness crowns were designed based on manufacturer guidelines with 1.5 mm occlusal thickness and 1.0 mm margins. Minimal thickness crowns were designed with 0.7 mm occlusal thickness and 0.5 mm margins. MZ100 composite and e.max abutments were selected to simulate dentin and enamel substrates, respectively, based on their elastic-modulus. Variolink Esthetic was used to cement all samples following manufacturer's instructions. A universal testing machine was used to load all specimens to fracture with a 3 mm radius stainless steel hemispherical tip at a crosshead speed 0.5 mm/minute along the longitudinal axis of the abutment with a 1 mm thermoplastic film placed between the loading tip and crown surface. Data was analyzed using ANOVA and Bonferroni post hoc assessment. Fractographic analysis was performed with scanning electron microscopy (SEM). RESULTS The mean fracture load (standard deviation) was 1499 (241) N for TD; 1228 (287) N for MD; and 1377 (96) N for ME. Statistically significant difference between groups did not exist (p = 0.157, F = 1.995). In groups TD and MD with low e-modulus abutments, the dispersion of a probability distribution (coefficient of variation: CV) was statistically higher than that of group ME with high e-modulus abutments. SEM illustrated larger micro-fracture dimensions in Group MD than Group ME. CONCLUSION Minimal thickness e.max crowns did not demonstrate statistical difference in fracture resistance from traditional thickness crowns. Fracture mechanisms of minimal thickness e.max crowns may be affected by the e-modulus of the substrate. Minimal thickness e.max crowns may be a viable restorative option when supported by high e-modulus materials.
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Affiliation(s)
- Sara Elizabeth Chen
- University of Illinois at Chicago - Restorative Dentistry, Chicago, IL, United States
| | | | - Jingxu Wang
- Department of Stomatology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Kent L Knoernschild
- University of Illinois at Chicago - Restorative Dentistry, Chicago, IL, United States
| | - Stephen Campbell
- University of Illinois at Chicago - Restorative Dentistry, Chicago, IL, United States
| | - Bin Yang
- University of Illinois at Chicago - Restorative Dentistry, Chicago, IL, United States
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Fatigue resistance of ultrathin CAD/CAM ceramic and nanoceramic composite occlusal veneers. Dent Mater 2019; 35:1370-1377. [PMID: 31351578 DOI: 10.1016/j.dental.2019.07.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 06/06/2019] [Accepted: 07/10/2019] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The fracture resistance of different ultrathin occlusal computer-aided design/computer-aided manufacturing (CAD/CAM) veneers was investigated under cyclic mechanical loading to restore combined enamel-dentin defects. METHODS Eighty-four molars were reduced occlusally until extensive dentin exposure occurred with a remaining enamel ring. Twenty-four molars were ground flat for examination of highly standardized specimens, of which 8 were treated with uniformly flat 0.3mm IPS Empress CAD and 0.3 and 0.5mm IPS e.max CAD restorations. Sixty-four molars were anatomically prepared until dentin exposure and were restored using occlusal veneers with fissure/cusp thicknesses of 0.3/0.5mm from 3 different dental CAD/CAM materials: IPS Empress CAD, IPS e.max CAD and Lava Ultimate CAD/CAM. Teeth were etched with 37% phosphoric acid, and occlusal veneers were bonded using an adhesive luting system (Syntac Primer, Adhesive, Heliobond and Variolink II). Specimens were placed under cyclic mechanical loading in a chewing simulator (1 million cycles at 50N) and were examined for cracks after each cyclic loading sequence. The anatomical 0.3/0.5mm IPS e.max CAD specimens experienced an additional 1 million cycles at 100N. Kaplan-Meier survival curves and log-rank tests were used for data analysis. RESULTS All highly standardized and 0.3/0.5mm IPS e.max CAD specimens tolerated cyclic loading. One anatomical Lava Ultimate CAD/CAM and 10 IPS Empress CAD specimens showed cracks. SIGNIFICANCE Ultrathin occlusal veneers of lithium disilicate ceramic and nanoceramic composite showed remarkably high fracture strength under cyclic mechanical loading. These veneers might be a tooth substance preserving option for restoring combined dentin-enamel defects.
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Zimmermann M, Ender A, Attin T, Mehl A. Fracture load of three-unit full-contour fixed dental prostheses fabricated with subtractive and additive CAD/CAM technology. Clin Oral Investig 2019; 24:1035-1042. [DOI: 10.1007/s00784-019-03000-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 06/28/2019] [Indexed: 10/26/2022]
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Thainimit I, Totiam P, Wayakanon K. Fracture Resistance of Remaining Buccal Cusps in Maxillary Premolar Ceramic Onlay Restorations. Oper Dent 2019; 45:0. [PMID: 32502265 DOI: 10.2341/19-251-l] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2019] [Indexed: 11/23/2022]
Abstract
Preparation designs for bondable partial coverage restorations are varied. As little as 1 mm of thickness of a remaining buccal cusp can be kept when restoring maxillary premolars with bondable partial coverage restorations.
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Affiliation(s)
- I Thainimit
- Itsalapong Thainimit, DDS, MSD, Restorative Dentistry, Naresuan University, Phitsanulok, Thailand
| | - P Totiam
- Potjaman Totiam, DDS, PhD, Restorative Dentistry, Naresuan University, Phitsanulok, Thailand
| | - K Wayakanon
- Kornchanok Wayakanon, DDS, MSD, PhD, Restorative Dentistry, Naresuan University, Phitsanulok, Thailand
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Al-Akhali M, Kern M, Elsayed A, Samran A, Chaar MS. Influence of thermomechanical fatigue on the fracture strength of CAD-CAM-fabricated occlusal veneers. J Prosthet Dent 2019; 121:644-650. [DOI: 10.1016/j.prosdent.2018.07.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 07/22/2018] [Accepted: 07/23/2018] [Indexed: 11/16/2022]
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PORTO TS, ROPERTO RC, AKKUS A, AKKUS O, TEICH S, FADDOUL F, PORTO-NETO ST, CAMPOS EA. Effect of storage and aging conditions on the flexural strength and flexural modulus of CAD/CAM materials. Dent Mater J 2019; 38:264-270. [DOI: 10.4012/dmj.2018-111] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Thiago Soares PORTO
- Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University
| | - Renato Cassio ROPERTO
- Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University
| | - Anna AKKUS
- Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University
- Department of Macromolecular Science and Engineering, School of Engineering, Case Western Reserve University
| | - Ozan AKKUS
- Department of Mechanical and Aerospace Engineering, School of Engineering, Case Western Reserve University
| | - Sorin TEICH
- Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University
| | - Fady FADDOUL
- Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University
| | | | - Edson Alves CAMPOS
- Department of Restorative Dentistry, Araraquara Faculty of Dentistry, Sao Paulo State University
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