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Lee JH, Seo JH, Park SW, Kim WG, Jung TG, Lee SJ. A Finite Element Analysis Study of Edentulous Model with Complete Denture to Simulate Masticatory Movement. Bioengineering (Basel) 2024; 11:336. [PMID: 38671758 PMCID: PMC11048550 DOI: 10.3390/bioengineering11040336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 03/22/2024] [Accepted: 03/26/2024] [Indexed: 04/28/2024] Open
Abstract
The purposes of this study are to establish and validate a finite element (FE) model using finite element analysis methods and to identify optimal loading conditions to simulate masticatory movement. A three-dimensional FE model of the maxillary and mandibular cortical bone, cancellous bone, and gingiva was constructed based on edentulous cone-beam-computed tomography data. Dental computer-aided design software was used to design the denture base and artificial teeth to produce a complete denture. Mesh convergence was performed to derive the optimal mesh size, and validation was conducted through comparison with mechanical test results. The mandible was rotated step-by-step to induce movements similar to actual mastication. Results showed that there was less than a 6% difference between the mechanical test and the alveolar bone-complete denture. It opened 10° as set in the first stage, confirming that the mouth closed 7° in the second stage. Occlusal contact occurred between the upper and lower artificial teeth as the mouth closed the remaining angle of 3° in the third stage while activating the masseter muscle. These results indicate that the FE model and masticatory loading conditions developed in this study can be applied to analyze biomechanical effects according to the wearing of dentures with various design elements applied.
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Affiliation(s)
- Jeong-Hyeon Lee
- Medical Device Research and Development Center, DENTIS Co., Ltd., Daegu 41065, Republic of Korea; (J.-H.L.); (J.-H.S.); (S.-W.P.)
- Department of Biomedical Engineering, Inje University, Gimhae-si 50834, Republic of Korea
| | - Jeong-Hee Seo
- Medical Device Research and Development Center, DENTIS Co., Ltd., Daegu 41065, Republic of Korea; (J.-H.L.); (J.-H.S.); (S.-W.P.)
| | - Shin-Wook Park
- Medical Device Research and Development Center, DENTIS Co., Ltd., Daegu 41065, Republic of Korea; (J.-H.L.); (J.-H.S.); (S.-W.P.)
| | - Won-Gi Kim
- Department of Dental Technology, Daegu Health College, Daegu 41453, Republic of Korea;
| | - Tae-Gon Jung
- Medical Device Development Center, Osong Medical Innovation Foundation, Cheongju-si 28160, Republic of Korea
| | - Sung-Jae Lee
- Department of Biomedical Engineering, Inje University, Gimhae-si 50834, Republic of Korea
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Igarashi M, Ohkuma K. Development of lightweight and high-strength hollow titanium-plated denture material using three-dimensional printing. Odontology 2024:10.1007/s10266-024-00923-3. [PMID: 38523208 DOI: 10.1007/s10266-024-00923-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 02/21/2024] [Indexed: 03/26/2024]
Abstract
Owing to its desirable ability to fabricate complex shapes, three-dimensional printing is preferred over casting for manufacturing dentures. Furthermore, titanium is widely used in dental implants and dentures because of its high corrosion resistance, biocompatibility, strength, and low density. In this study, we aimed to develop a new metal denture material from three-dimensional-printed (3DP) to achieve lighter weight and greater strength than those of PMMA dentures. Hollow (3DP-H) structure and solid (3DP-S) structure titanium plate specimens of 0.5, 1.0, and 3.0 mm in thickness were used. Casted Ti, casted Co-Cr, and PMMA plates were fabricated for comparison. Elastic modulus, density, thermal conductivity, hardness, and proof stress of the specimens were measured and plotted on a radar chart to enable multifaceted evaluation. The results indicated that the density of the 3DP-H plates reduced by 28-36% compared with those of 3DP-S and cast Ti plates. The weight of the metal-denture-equivalent section of the 0.5-mm-thick 3DP-H titanium-plated denture reduced to two-thirds that of the 2.0-mm-thick PMMA denture. The proof stress of the 0.5-mm-thick 3DP-H plate increased to about 3 times that of the 2.0-mm-thick PMMA plate. The total value of the 0.5-mm-thick 3DP-H titanium plates was higher than it of the 1.0-mm-thick PMMA plates. This study suggests that it is possible to produce 3DP-H titanium plate dentures exhibiting not only extremely lightweight compared to conventional PMMA dentures but also sufficient strength.
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Affiliation(s)
- Masahiro Igarashi
- Course of Applied Science, Field of Developmental Science of Oral Biomaterials, The Nippon Dental University Graduate School of Life Dentistry at Niigata, 1-8 Hamaura-cho, Chuo-ku, Niigata City, Niigata, 951-8580, Japan.
| | - Kazuo Ohkuma
- Course of Applied Science, Field of Developmental Science of Oral Biomaterials, The Nippon Dental University Graduate School of Life Dentistry at Niigata, 1-8 Hamaura-cho, Chuo-ku, Niigata City, Niigata, 951-8580, Japan
- Department of Dental Materials Science, The Nippon Dental University School of Life Dentistry at Niigata, 1-8 Hamaura-cho, Chuo-ku, Niigata City, Niigata, 951-8580, Japan
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Temizci T, Bozoğulları HN. Effect of thermal cycling on the flexural strength of 3-D printed, CAD/CAM milled and heat-polymerized denture base materials. BMC Oral Health 2024; 24:357. [PMID: 38509542 PMCID: PMC10953149 DOI: 10.1186/s12903-024-04122-y] [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: 08/23/2023] [Accepted: 03/07/2024] [Indexed: 03/22/2024] Open
Abstract
BACKGROUND This study compared the impact of thermal cycling on the flexural strength of denture-base materials produced through conventional and digital methods, using both subtractive and additive approaches. METHODS In total, 60 rectangular specimens were fabricated with specific dimensions for flexural strength tests. The dimensions were set according to the International Organization for Standardization (ISO) guideline 20795-1:2013 as 64 × 10 × 3.3 ± 0.2 mm. Specimens from each material group were divided into two subgroups (thermal cycled or nonthermal cycled, n = 10/group). We used distinct methods to produce three different denture-base materials: Ivobase (IB), which is a computer-aided-design/computer-aided-manufacturing-type milled pre-polymerized polymethyl methacrylate resin disc; Formlabs (FL), a 3D-printed denture-base resin; and Meliodent (MD), a conventional heat-polymerized acrylic. Flexural strength tests were performed on half of the samples without a thermal-cycle procedure, and the other half were tested after a thermal cycle. The data were analyzed using a two-way analysis of variance and a post hoc Tukey test (α = 0.05). RESULTS Based on the results of flexural-strength testing, the ranking was as follows: FL > IB > MD. The effect of thermal aging was statistically significant for the FL and IB bases, but not for the MD base. CONCLUSIONS Digitally produced denture bases exhibited superior flexural strength compared with conventionally manufactured bases. Although thermal cycling reduced flexural strength in all groups, the decrease was not statistically significant in the heat-polymerized acrylic group.
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Affiliation(s)
- Tuğba Temizci
- Department of Prosthodontics, Faculty of Dentistry, Karamanoğlu Mehmetbey University, Karaman, Turkey.
| | - Hatice Nalan Bozoğulları
- Department of Prosthodontics, Faculty of Dentistry, Karamanoğlu Mehmetbey University, Karaman, Turkey
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Montoya C, Kurylec J, Ossa A, Orrego S. Cyclic strain of poly (methyl methacrylate) surfaces triggered the pathogenicity of Candida albicans. Acta Biomater 2023; 170:415-426. [PMID: 37625677 DOI: 10.1016/j.actbio.2023.08.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/21/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023]
Abstract
Candida albicans is an opportunistic yeast and the primary etiological factor in oral candidiasis and denture stomatitis. The pathogenesis of C. albicans could be triggered by several variables, including environmental, nutritional, and biomaterial surface cues. Specifically, biomaterial interactions are driven by different surface properties, including wettability, stiffness, and roughness. Dental biomaterials experience repetitive (cyclic) stresses from chewing and biomechanical movements. Pathogenic biofilms are formed over these biomaterial surfaces under cyclic strain. This study investigated the effect of the cyclic strain (deformation) of biomaterial surfaces on the virulence of Candida albicans. Candida biofilms were grown over Poly (methyl methacrylate) (PMMA) surfaces subjected to static (no strain) and cyclic strain with different levels (ε˜x=0.1 and 0.2%). To evaluate the biomaterial-biofilm interactions, the biofilm characteristics, yeast-to-hyphae transition, and the expression of virulent genes were measured. Results showed the biofilm biomass and metabolic activity to be significantly higher when Candida adhered to surfaces subjected to cyclic strain compared to static surfaces. Examination of the yeast-to-hyphae transition showed pseudo-hyphae cells (pathogenic) in cyclically strained biomaterial surfaces, whereas static surfaces showed spherical yeast cells (commensal). RNA sequencing was used to determine and compare the transcriptome profiles of cyclically strained and static surfaces. Genes and transcription factors associated with cell adhesion (CSH1, PGA10, and RBT5), biofilm formation (EFG1), and secretion of extracellular matrix (ECM) (CRH1, ADH5, GCA1, and GCA2) were significantly upregulated in the cyclically strained biomaterial surfaces compared to static ones. Genes and transcription factors associated with virulence (UME6 and HGC1) and the secretion of extracellular enzymes (LIP, PLB, and SAP families) were also significantly upregulated in the cyclically strained biomaterial surfaces compared to static. For the first time, this study reveals a biomaterial surface factor triggering the pathogenesis of Candida albicans, which is essential for understanding, controlling, and preventing oral infections. STATEMENT OF SIGNIFICANCE: Fungal infections produced by Candida albicans are a significant contributor to various health conditions. Candida becomes pathogenic when certain environmental conditions change, including temperature, pH, nutrients, and CO2 levels. In addition, surface properties, including wettability, stiffness, and roughness, drive the interactions between Candida and biomaterials. Clinically, Candida adheres to biomaterials that are under repetitive deformation due to body movements. In this work, we revealed that when Candida adhered to biomaterial surfaces subjected to repetitive deformation, the microorganism becomes pathogenic by increasing the formation of biofilms and the expression of virulent factors related to hyphae formation and secretion of enzymes. Findings from this work could aid the development of new strategies for treating fungal infections in medical devices or implanted biomaterials.
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Affiliation(s)
- Carolina Montoya
- Department of Oral Health Sciences, Kornberg School of Dentistry, Temple University, Philadelphia, PA, United States
| | - Julia Kurylec
- Department of Oral Health Sciences, Kornberg School of Dentistry, Temple University, Philadelphia, PA, United States
| | - Alex Ossa
- Production Engineering Department, School of Engineering, Universidad EAFIT, Medellín, Colombia
| | - Santiago Orrego
- Department of Oral Health Sciences, Kornberg School of Dentistry, Temple University, Philadelphia, PA, United States; Bioengineering Department, College of Engineering, Temple University, Philadelphia, PA, United States.
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Teodorescu C, Preoteasa E, Preoteasa CT, Murariu-Măgureanu C, Teodorescu IM. The Biomechanical Impact of Loss of an Implant in the Treatment with Mandibular Overdentures on Four Nonsplinted Mini Dental Implants: A Finite Element Analysis. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8662. [PMID: 36500160 PMCID: PMC9739263 DOI: 10.3390/ma15238662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 12/01/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
The aim of this study was to evaluate the biomechanical impact, in terms of stress and displacement, at the level of a mandibular overdenture, on four mini dental implants (MDIs) after the loss of an implant. A three-dimensional virtual model was obtained by scanning the overdenture, and a biomechanical analysis was carried out, using the finite element method (FEM). The displacements of the overdenture and the equivalent von Mises stresses were evaluated using logarithmic scales. In the case of a mandibular overdenture on four MDIs inserted in the interforaminal area, the frontal loading generated the lowest values for the von Mises stresses, and the bilateral loading generated the least displacement when two implants were inserted in the canine area and two in the molar area. The highest von Mises stress was observed during frontal loading in the situation of the mandibular overdenture on four MDIs, two of which were inserted in the canine area and two in the molar area, following the loss of an implant in the canine area. The largest displacement was noted in the mandibular overdenture on four interforaminal MDIs during unilateral loading, following the loss of a distally inserted implant. The FEM analysis showed aspects that correlated with clinical observations, with predictive value. The concentration of von Mises stresses, and the occurrence of some displacements of the prosthodontic restoration, can explain the emergence of some complications in the overdenture's biodynamics, and the increased risk of fracture. Complications can be prevented by choosing a certain number of implants and a topographical distribution correlated with biomechanical aspects, and by proposing a correct occlusal scheme with optimal functional loading.
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Affiliation(s)
- Cristian Teodorescu
- Department of Prosthodontics, Faculty of Dentistry, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Elena Preoteasa
- Department of Prosthodontics, Faculty of Dentistry, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Cristina Teodora Preoteasa
- Department of Scientific Research Methods-Ergonomics, Faculty of Dentistry, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Cătălina Murariu-Măgureanu
- Department of Prosthodontics, Faculty of Dentistry, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Ioana Monica Teodorescu
- Department of Prosthodontics, Faculty of Dentistry, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania
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Grachev DI, Ruzuddinov NS, Arutyunov AS, Akhmedov GD, Dubova LV, Kharakh YN, Panin SV, Arutyunov SD. Algorithm for Designing a Removable Complete Denture (RCD) Based on the FEM Analysis of Its Service Life. MATERIALS (BASEL, SWITZERLAND) 2022; 15:7246. [PMID: 36295314 PMCID: PMC9610509 DOI: 10.3390/ma15207246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 10/10/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
(1) Background: The paper addresses the computer simulation and prediction of the service life of the base of removable complete dentures (RCDs) under typical loads caused by biting and chewing food. For this purpose, the finite element method (FEM) was used. It is assumed that various blocks of teeth, such as incisors, canines, premolars and molars, are subjected to cyclic impacts during a human life. (2) Methods: Both symmetric and asymmetric mastication (two- and one-sided loads, respectively) cases were considered. The load level was assumed to be 100 N, which corresponds to the average muscular compression force of typical human jaws. (3) Results: The FEM analysis of the stress-strain state evolution for RCDs under cyclic loads was carried out. Maps of equivalent lines were drawn for the denture base in terms of its durability. A multi-axial criterion was implemented to determine the number of cycles prior to failure by the mechanism of a normal opening mode crack. The FEM-based assessment of the service life of RCDs enabled us to establish the critical stress concentration areas, thereby allowing for further planning for the correction of an occlusal scheme or teeth inclinations. As a result, the service life of RCDs under cyclic loading can be improved. (4) Conclusions: An algorithm for designing RCDs in the case of edentulism based on the FEM simulation using commercial software as part of the procedure is proposed.
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Affiliation(s)
- Dmitry I. Grachev
- Digital Dentistry Department, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, 127473 Moscow, Russia
| | | | - Anatoliy S. Arutyunov
- Propaedeutics of Prosthetics Technologies in Dentistry Department, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, 127473 Moscow, Russia
| | - Gadzhi D. Akhmedov
- Propaedeutics in Surgical Dentistry, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, 127473 Moscow, Russia
| | - Lubov V. Dubova
- Orthopedic Dentistry Department, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, 127473 Moscow, Russia
| | - Yaser N. Kharakh
- Digital Dentistry Department, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, 127473 Moscow, Russia
| | - Sergey V. Panin
- Laboratory of Mechanics of Polymer Composite Materials, Institute of Strength Physics and Materials Science of Siberian Branch of Russian Academy of Sciences, 634055 Tomsk, Russia
| | - Sergey D. Arutyunov
- Digital Dentistry Department, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, 127473 Moscow, Russia
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Calamote C, Coelho IC, Silva AS, Esteves JL, Moreira L, Pinto AC, Manzanares-Céspedes MC, Escuín T. Comparison of the Masticatory Force (with 3D Models) of Complete Denture Base Acrylic Resins with Reline and Reinforcing Materials. MATERIALS 2021; 14:ma14123308. [PMID: 34203948 PMCID: PMC8232668 DOI: 10.3390/ma14123308] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 06/10/2021] [Accepted: 06/10/2021] [Indexed: 01/29/2023]
Abstract
The reinforcement of acrylic denture base remains problematic. Acrylic prosthesis fractures are commonly observed in prosthodontic practice and have not been reliably resolved. This study compared the resistance to masticatory force of acrylic bases of removable complete conventional prosthesis in 3D upper models. Forty acrylic base test specimens containing two types of reinforcement meshes (20 with glass fiber meshes (FIBER-FORCE®- Synca, Bio Composants MédicauxTM, Tullins, France), 20 with metal meshes (DENTAURUM®-Ispringen, Germany)), 20 with a conventional PMMA acrylic base (LUCITONE 199®-Dentsply Sirona, York, PA, USA), and 20 using a permanent soft reline material (MOLLOPLAST-B®-DETAX GmbH & Co. KG, Ettlingen, Germany) were tested—a total of 80 specimens. Half of the specimens were made for a low alveolar ridge and half for a high alveolar ridge. The data were analysed using one-way analysis of variance and Student’s t-test for independent test specimens. In the high-alveolar-ridge group, the prosthesis reinforced with the glass fiber mesh was the most resistant to fracture, while in the low-alveolar-ridge group, the non-reinforced prosthesis showed the highest resistance masticatory force. Prostheses with the permanent soft reline material showed the lowest resistance to fracture in both high and low-alveolar-ridge groups. The results show that the selection of the right reinforcement material for each clinical case, based on the height of the alveolar ridge, may help to prevent prosthesis fractures.
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Affiliation(s)
- Catarina Calamote
- Department of Oral Rehabilitation, Instituto Universitário de Ciências da Saúde, 4585-116 Gandra, Portugal; (C.C.); (I.C.C.); (A.C.P.)
| | - Isabel Carolina Coelho
- Department of Oral Rehabilitation, Instituto Universitário de Ciências da Saúde, 4585-116 Gandra, Portugal; (C.C.); (I.C.C.); (A.C.P.)
| | - António Sérgio Silva
- Dental Science Department, Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde, Rua Central da Gandra 1317, 4585-116 Gandra, Portugal
- Correspondence: ; Tel.: +351-918-725-156
| | - José Luís Esteves
- Department of Mechanical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal;
| | - Luís Moreira
- RECI–Research in Education and Community Intervention, Escola Superior de Saúde Jean Piaget, 4405-678 Vila Nova de Gaia, Portugal;
| | - António Correia Pinto
- Department of Oral Rehabilitation, Instituto Universitário de Ciências da Saúde, 4585-116 Gandra, Portugal; (C.C.); (I.C.C.); (A.C.P.)
| | | | - Tomás Escuín
- Department of Rehabilitation and Maxillofacial Prostheses, Faculty of Odontology, University of Barcelona, 08007 Barcelona, Spain;
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Relationships of Stresses on Alveolar Bone and Abutment of Dental Implant from Various Bite Forces by Three-Dimensional Finite Element Analysis. BIOMED RESEARCH INTERNATIONAL 2020; 2020:7539628. [PMID: 32149132 PMCID: PMC7049827 DOI: 10.1155/2020/7539628] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 12/02/2019] [Accepted: 01/23/2020] [Indexed: 11/24/2022]
Abstract
Occlusal trauma caused by improper bite forces owing to the lack of periodontal membrane may lead to bone resorption, which is still a problem for the success of dental implant. In our study, to avoid occlusal trauma, we put forward a hypothesis that a microelectromechanical system (MEMS) pressure sensor is settled on an implant abutment to track stress on the abutment and predict the stress on alveolar bone for controlling bite forces in real time. Loading forces of different magnitudes (0 N–100 N) and angles (0–90°) were applied to the crown of the dental implant of the left central incisor in a maxillary model. The stress distribution on the abutment and alveolar bone were analyzed using a three-dimensional finite element analysis (3D FEA). Then, the quantitative relation between them was derived using Origin 2017 software. The results show that the relation between the loading forces and the stresses on the alveolar bone and abutment could be described as 3D surface equations associated with the sine function. The appropriate range of stress on the implant abutment is 1.5 MPa–8.66 MPa, and the acceptable loading force range on the dental implant of the left maxillary central incisor is approximately 6 N–86 N. These results could be used as a reference for the layout of MEMS pressure sensors to maintain alveolar bone dynamic remodeling balance.
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Efficacy of different designs of mandibular expanders: A 3-dimensional finite element study. Am J Orthod Dentofacial Orthop 2020; 157:641-650. [PMID: 32354437 DOI: 10.1016/j.ajodo.2019.05.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 05/01/2019] [Accepted: 05/01/2019] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Nonsurgical mandibular expansion has been increasingly performed in recent years because it can effectively expand the mandibular dental arch. However, many types of mandibular expanders have been used in previous studies. No relevant studies have compared the biomechanical responses of different designs of mandibular expansion appliances with screws. Therefore, the purpose of this study was to analyze the stress distribution and displacement of the dentoalveolar structures according to different designs of mandibular screw expanders. METHODS Cone-beam computed tomography scans were used for 3-dimensional reconstruction of the mandibular finite element model. Four different designs of mandibular expanders, 1 removable expander (type A) and 3 fixed expanders (types B, C, and D), were added to the finite element models. Expanders were activated transversely for 0.2 mm. The initial tooth displacement and von Mises stress distribution were evaluated. RESULTS All the expanders enlarged the arch dimensions. In types A and B, the stress was mainly concentrated in the region of the anterior teeth, along with greater tooth displacement, whereas in types C and D, greater stress and displacement occurred in the region of the posterior teeth. Type A showed the greatest amount of transverse displacement. Type D was more efficient in the region of the posterior teeth. CONCLUSIONS Types A and B should be used with great caution in the clinic because of their incompatible expansion pattern. Type D is the recommended mandibular expansion appliance because of its appropriate expansion pattern.
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Jamayet N, Mousa M, Lynch E, Husein A. Biomechanical stress in removable complete dental prostheses: a narrative review of finite element studies. J Int Oral Health 2020. [DOI: 10.4103/jioh.jioh_190_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Tercanli Alkis H, Turker N. Retrospective evaluation of marginal bone loss around implants in a mandibular locator-retained denture using panoramic radiographic images and finite element analysis: A pilot study. Clin Implant Dent Relat Res 2019; 21:1199-1205. [PMID: 31625683 DOI: 10.1111/cid.12857] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/30/2019] [Accepted: 10/04/2019] [Indexed: 01/21/2023]
Abstract
BACKGROUND The follow-up of the peri-implant marginal bone loss is the most important criterion for the determination of implant success. PURPOSE The purpose of this study is to measure marginal bone loss using panoramic radiographic images (PRI) of patients treated using a mandibular, two implant-supported, locator-retained denture and to evaluate the compatibility of these findings with those of the finite element analysis (FEA). MATERIALS AND METHODS The PRI of patients who had a mandibular, two implant-supported, locator-retained denture were assessed, and the mesial and distal marginal bone loss of both right- and left-sided implants was measured. Mandibular and maxillary models, which have the features of bilateral balanced occlusion, were created. The surfaces of the generated models were converted in a computer-aided design model that could be transferred to the FEA software, and the forces were defined on contacts formed in maximum intercuspation, lateral, and protrusive movement position for bilateral balanced occlusion. RESULTS The bone loss in the mesial and distal regions at the right- and left-sided implants was not statistically significant. Higher stresses were formed on the vestibular side under protrusive movement, on the lingual side under maximum intercuspation, on the distolingual side under left unilateral biting, and on the mesiolingual side under right unilateral biting in the FEA. CONCLUSION According to FEA, peri-implant bone resorption may be higher in the buccal and palatal regions, implying that panoramic radiographs can be misleading in understanding the amount of peri-implant bone resorption.
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Affiliation(s)
- Humeyra Tercanli Alkis
- Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, University of Akdeniz, Antalya, Turkey
| | - Nurullah Turker
- Department of Prosthetics, Faculty of Dentistry, University of Akdeniz, Antalya, Turkey
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12
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Aguirre BC, Chen JH, Kontogiorgos ED, Murchison DF, Nagy WW. Flexural strength of denture base acrylic resins processed by conventional and CAD-CAM methods. J Prosthet Dent 2019; 123:641-646. [PMID: 31353106 DOI: 10.1016/j.prosdent.2019.03.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 03/14/2019] [Accepted: 03/14/2019] [Indexed: 11/19/2022]
Abstract
STATEMENT OF PROBLEM High flexural strength is one of the desirable properties for denture base resins, yet only few studies have evaluated the physical properties of newer denture bases such as computer-aided design and computer aided manufacturing (CAD-CAM) milled products. PURPOSE The purpose of this in vitro study was to compare the flexural strength of 3 different types of denture base resins: compression molded, injection molded, and CAD-CAM milled. MATERIAL AND METHODS Three groups (n=10) of acrylic denture base resins were tested: injection molded, compression molded, and CAD-CAM milled resin. ISO-compliant, rectangular specimens were fabricated (64×10×3.3 mm) (n=30). Specimens were stored in water for 1 week, and flexural strength was measured by using a 3-point bend test until failure. The Student t test was used to evaluate differences in the flexural strength and modulus of elasticity among specimen groups. The Bonferroni formula was used to set significance at α=.017 to account for multiple comparisons among the 3 groups. RESULTS The flexural strength of the CAD-CAM milled group was significantly higher than that of the other 2 groups (P<.001), while the strength of the compression molded group was significantly greater than that of the injection molded group (P<.001). The flexural modulus of the CAD-CAM group was significantly higher than that of the other 2 groups (P<.001). CONCLUSIONS CAD-CAM milled denture bases may be a useful alternative to conventionally processed denture bases in situations where increased resistance to flexural strength is needed.
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Affiliation(s)
- Brian C Aguirre
- Former Graduate Prosthodontics Resident, Department of Restorative Sciences, Texas A&M University College of Dentistry, Dallas, Texas
| | - Jenn-Hwan Chen
- Clinical Assistant Professor, Department of Restorative Sciences, Texas A&M University College of Dentistry, Dallas, Texas.
| | - Elias D Kontogiorgos
- Professor, Department of Restorative Sciences, Texas A&M University College of Dentistry, Dallas, Texas
| | - David F Murchison
- Adjunct Professor, Department of Diagnostic Sciences, Texas A&M University College of Dentistry, Dallas, Texas
| | - William W Nagy
- Associate Professor, Department of Restorative Sciences, Texas A&M University College of Dentistry, Dallas, Texas
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Röhrle O, Saini H, Lee PVS, Ackland DC. A novel computational method to determine subject-specific bite force and occlusal loading during mastication. Comput Methods Biomech Biomed Engin 2018; 21:453-460. [PMID: 30010417 DOI: 10.1080/10255842.2018.1479744] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The evaluation of three-dimensional occlusal loading during biting and chewing may assist in development of new dental materials, in designing effective and long-lasting restorations such as crowns and bridges, and for evaluating functional performance of prosthodontic components such as dental and/or maxillofacial implants. At present, little is known about the dynamic force and pressure distributions at the occlusal surface during mastication, as these quantities cannot be measured directly. The aim of this study was to evaluate subject-specific occlusal loading forces during mastication using accurate jaw motion measurements. Motion data was obtained from experiments in which an individual performed maximal effort dynamic chewing cycles on a rubber sample with known mechanical properties. A finite element model simulation of one recorded chewing cycle was then performed to evaluate the deformation of the rubber. This was achieved by imposing the measured jaw motions on a three-dimensional geometric surface model of the subject's dental impressions. Based on the rubber's deformation and its material behaviour, the simulation was used to compute the resulting stresses within the rubber as well as the contact pressures and forces on the occlusal surfaces. An advantage of this novel modelling approach is that dynamic occlusal pressure maps and biting forces may be predicted with high accuracy and resolution at each time step throughout the chewing cycle. Depending on the motion capture technique and the speed of simulation, the methodology may be automated in such a way that it can be performed chair-side. The present study demonstrates a novel modelling methodology for evaluating dynamic occlusal loading during biting or chewing.
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Affiliation(s)
- Oliver Röhrle
- a Institute of Applied Mechanics (Civil Engineering) , University of Stuttgart , Stuttgart , Germany.,b Cluster of Excellence for Simulation Technology (SimTech) , Stuttgart , Germany.,c Biomechatronic Systems , Fraunhofer Institute for Manufacturing Engineering and Automation IPA , Stuttgart , Germany
| | - Harnoor Saini
- a Institute of Applied Mechanics (Civil Engineering) , University of Stuttgart , Stuttgart , Germany
| | - Peter V S Lee
- d Department of Biomedical Engineering , The University of Melbourne , Parkville , Australia
| | - David C Ackland
- d Department of Biomedical Engineering , The University of Melbourne , Parkville , Australia
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14
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Khuder T, Yunus N, Sulaiman E, Dabbagh A. Finite element analysis and clinical complications in mandibular implant-overdentures opposing maxillary dentures. J Mech Behav Biomed Mater 2017; 75:97-104. [PMID: 28709037 DOI: 10.1016/j.jmbbm.2017.06.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 06/25/2017] [Accepted: 06/30/2017] [Indexed: 10/19/2022]
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15
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Yu SH, Oh S, Cho HW, Bae JM. Reinforcing effect of glass-fiber mesh on complete dentures in a test model with a simulated oral mucosa. J Prosthet Dent 2017; 118:650-657. [PMID: 28545871 DOI: 10.1016/j.prosdent.2017.03.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 03/17/2017] [Accepted: 03/17/2017] [Indexed: 11/16/2022]
Abstract
STATEMENT OF PROBLEM Studies that evaluated the strength of complete dentures reinforced with glass-fiber mesh or metal mesh on a cast with a simulated oral mucosa are lacking. PURPOSE The purpose of this in vitro study was to compare the mechanical properties of maxillary complete dentures reinforced with glass-fiber mesh with those of metal mesh in a new test model, using a simulated oral mucosa. MATERIAL AND METHODS Complete dentures reinforced with 2 types of glass-fiber mesh, SES mesh (SES) and glass cloth (GC) and metal mesh (metal) were fabricated. Complete dentures without any reinforcement were prepared as a control (n=10). The complete dentures were located on a cast with a simulated oral mucosa, and a load was applied on the posterior artificial teeth bilaterally. The fracture load, elastic modulus, and toughness of a complete denture were measured using a universal testing machine at a crosshead speed of 5 mm/min. The fracture load and elastic modulus were analyzed using 1-way analysis of variance, and the toughness was analyzed with the Kruskal-Wallis test (α=.05). The Tukey multiple range test was used as a post hoc test. RESULTS The fracture load and toughness of the SES group was significantly higher than that of the metal and control groups (P<.05) but not significantly different from that of the GC group. The elastic modulus of the metal group was significantly higher than that of the control group (P<.05), and no significant differences were observed in the SES and GC groups. CONCLUSIONS Compared with the control group, the fracture load and toughness of the SES and GC groups were higher, while those of the metal group were not significantly different.
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Affiliation(s)
- Sang-Hui Yu
- Postdoctoral Researcher, Department of Dental Biomaterials, College of Dentistry, Wonkwang University, Jeonbuk, Republic of Korea
| | - Seunghan Oh
- Associate Professor, Department of Dental Biomaterials and Institute of Biomaterials-Implant, College of Dentistry, Wonkwang University, Jeonbuk, Republic of Korea
| | - Hye-Won Cho
- Professor, Department of Prosthodontics, College of Dentistry, Wonkwang University, Jeonbuk, Republic of Korea
| | - Ji-Myung Bae
- Professor, Department of Dental Biomaterials, College of Dentistry, Institute of Skeletal Disease, Wonkwang University, Jeonbuk, Republic of Korea.
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16
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Gad MM, Fouda SM, ArRejaie AS, Al‐Thobity AM. Comparative Effect of Different Polymerization Techniques on the Flexural and Surface Properties of Acrylic Denture Bases. J Prosthodont 2017; 28:458-465. [DOI: 10.1111/jopr.12605] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2017] [Indexed: 11/26/2022] Open
Affiliation(s)
- Mohammed M. Gad
- Department of Substitutive Dental SciencesCollege of Dentistry, University of Dammam Dammam Saudi Arabia
| | - Shaimaa M. Fouda
- Department of Substitutive Dental SciencesCollege of Dentistry, University of Dammam Dammam Saudi Arabia
| | - Aws S. ArRejaie
- Prosthetic dental sciences DepartmentCollege of Dentistry, King Saud University Riyadh Saudi Arabia
| | - Ahmad M. Al‐Thobity
- Department of Substitutive Dental SciencesCollege of Dentistry, University of Dammam Dammam Saudi Arabia
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17
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Ogawa T, Sato Y, Kitagawa N, Nakatsu M. Relationship between retention forces and stress at the distal border in maxillary complete dentures: Measurement of retention forces and finite-element analysis in individual participants. J Prosthet Dent 2017; 117:524-531. [DOI: 10.1016/j.prosdent.2016.08.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 08/11/2016] [Accepted: 08/11/2016] [Indexed: 11/25/2022]
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18
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Ishak MI, Ahmad Shafi A, Abdul Kadir MR, Sulaiman E. Effect of Ferrule Height and Post Length on Mechanical Stress and Displacement of Endodontically Treated Maxillary Central Incisor: A Finite Element Analysis. J Med Biol Eng 2017. [DOI: 10.1007/s40846-017-0227-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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19
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Shrivastava R, Chaturvedi S, Verma AK, Ali M, Nagendra A, Chaturvedi M. Stress Distribution under Commercial Denture Liners- A Finite Element and Clinical Analysis. J Clin Diagn Res 2017; 10:ZC14-ZC18. [PMID: 28208996 DOI: 10.7860/jcdr/2016/21466.9027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 08/30/2016] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Previous studies have shown that 20-30% of denture users have been dissatisfied with their dentures. AIM To evaluate the stress pattern under elastic and viscoelastic denture liners using 3-Dimensional Finite Element Analysis (FEA) and its clinical correlation using a questionnaire. MATERIALS AND METHODS The study had both in-vitro and in-vivo phases. In in-vitro phase fabrication of a virtual parametric model of edentulous maxilla and dentures with overlying mucosa was made. A virtual load of 166N was analyzed at three points (Point A=anterior ridge, Point B=right posterior ridge and Point C=left posterior ridge). For the in-vivo phase, 20 edentulous patients were provided conventional complete dentures (Group-I). The dentures were lined with silicone (elastic) liners (Group-II) and acrylic resins (viscoelastic) liners (Group-III) at regular (2 months) intervals. After each reline, the patients were evaluated using food eating ability and denture assessment questionnaires. The results were statistically analyzed. The statistical analysis was done using SPSS (Statistical Package for Social Sciences) version 15.0 statistical analysis software. Other than standard statistical test Analysis of Variance (ANOVA) and Post-Hoc tests (Tukey-HSD) were used. RESULTS At loading, the in-vitro result for Groups-II and III revealed pressures of 0.074231N and 0.0678364N at Point A, 0.098764N and 0.093642N at Point B, and 0.099876N and 0.093746N at Point C respectively. The in-vivo study revealed that the mean quality of life score for different groups ranged from 23.65±4.00 (Group I) to 33.10±6.15 (Group III). The mean quality of life score for Group II was 29.50±5.08. CONCLUSION The viscoelastic liner provided the most uniform stress distribution and performed better than an elastic liner with hard, firm and soft foods.
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Affiliation(s)
- Rahul Shrivastava
- Clinical Practitioner, Dental Care Oral Implantology Center and Axiss Dental Pvt., Ltd. , DLF Phase 1, Gurugram, Haryana, India
| | - Saurabh Chaturvedi
- Assistant Professor, Department of Prosthodontics, College of Dentistry, King Khalid University , Abha, Saudi Arabia
| | - Ashok Kumar Verma
- Professor and Head, Department of Prosthodontics, Career Post Graduate Institute of Dental Sciences , Lucknow, Uttar Pradesh, India
| | - Mariyum Ali
- Professor, Department of Prosthodontics, Career Post Graduate Institute of Dental Sciences , Lucknow, Uttar Pradesh, India
| | - Amrita Nagendra
- Clinical Practitioner, Dental Care Oral Implantology Center and Axiss Dental Pvt., Ltd. , DLF Phase 1, Gurugram, Haryana, India
| | - Mudita Chaturvedi
- Assistant Professor, Department of Oral Pathology, Career Post Graduate Institute of Dental Sciences , Lucknow, Uttar Pradesh, India
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Abstract
The prevalence of prosthodontic treatment has been well recognized, and the need is continuously increasing with the ageing population. While the oral mucosa plays a critical role in the treatment outcome, the associated biomechanics is not yet fully understood. Using the literature available, this paper provides a critical review on four aspects of mucosal biomechanics, including static, dynamic, volumetric and interactive responses, which are interpreted by its elasticity, viscosity/permeability, apparent Poisson's ratio and friction coefficient, respectively. Both empirical studies and numerical models are analysed and compared to gain anatomical and physiological insights. Furthermore, the clinical applications of such biomechanical knowledge on the mucosa are explored to address some critical concerns, including stimuli for tissue remodelling (interstitial hydrostatic pressure), pressure–pain thresholds, tissue displaceability and residual bone resorption. Through this review, the state of the art in mucosal biomechanics and their clinical implications are discussed for future research interests, including clinical applications, computational modelling, design optimization and prosthetic fabrication.
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Affiliation(s)
- Junning Chen
- School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Rohana Ahmad
- Unit of Prosthodontics, Faculty of Dentistry, Universiti Teknologi MARA, Shah Alam 40450, Malaysia
| | - Wei Li
- School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Michael Swain
- Faculty of Dentistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Qing Li
- School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Sydney, New South Wales 2006, Australia
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Oswal MM, Amasi UN, Oswal MS, Bhagat AS. Influence of three different implant thread designs on stress distribution: A three-dimensional finite element analysis. J Indian Prosthodont Soc 2016; 16:359-365. [PMID: 27746600 PMCID: PMC5062138 DOI: 10.4103/0972-4052.191283] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Purpose: Clinical success of implant prosthodontics is dependent in part upon the type of implant thread design. The selection of implant thread design plays an important role in the outcome of the treatment. This study was undertaken to evaluate the pattern of stress distribution using a finite element analysis; hence, the area which would be bearing maximum load for a given design would be arrived. Materials and Methods: Three implants with different thread designs, namely V-thread, buttress, and reverse buttress thread designs were considered and dimensions were standardized. The site considered was the mandibular molar region with cortical and trabecular bone assuming to be isotropic and homogeneous. The implant modeling was done with the CATIA software. Vertical loads of 100N were applied. The stresses were calculated as Von Mises stress criterion. Results: Maximum stresses were seen at the cortical bone and were transferred to the implant. Minimum Von Mises stresses were seen with reverse buttress thread design at the cortical bone. The stresses were observed least at the cancellous bone and maximum at the implant. Conclusion: Hence, within the limitations of this study the results obtained can be applied clinically for appropriate selection of implant thread design for a predictable success of implant therapy.
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Affiliation(s)
- Mansi Manish Oswal
- Department of Prosthodontics, D. Y. Patil Dental School, D. Y. Patil Knowledge City, Lohegoan, Charholi Budruk, Pune, Maharashtra, India
| | - Ulhas N Amasi
- Department of Prosthodontics, KLE V K Institute of Dental Sciences, JNMC Campus, Belgaum, Karnataka, India
| | - Manish S Oswal
- Department of Prosthodontics, D. Y. Patil Dental School, D. Y. Patil Knowledge City, Lohegoan, Charholi Budruk, Pune, Maharashtra, India
| | - Ashish S Bhagat
- Department of Prosthodontics, D. Y. Patil Dental School, D. Y. Patil Knowledge City, Lohegoan, Charholi Budruk, Pune, Maharashtra, India
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22
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Effect of home reliner on occlusal relationships and oral mucosa: viscoelastic analyses by smoothed particle hydrodynamics simulation. Comput Biol Med 2015; 66:20-8. [DOI: 10.1016/j.compbiomed.2015.07.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 11/18/2022]
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23
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Yu SH, Cho HW, Oh S, Bae JM. Effects of glass fiber mesh with different fiber content and structures on the compressive properties of complete dentures. J Prosthet Dent 2015; 113:636-44. [PMID: 25794912 DOI: 10.1016/j.prosdent.2014.10.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 10/29/2014] [Accepted: 10/29/2014] [Indexed: 10/23/2022]
Abstract
STATEMENT OF PROBLEM No study has yet evaluated the strength of complete dentures reinforced with glass fiber meshes with different content and structures. PURPOSE The purpose of this study was to compare the reinforcing effects of glass fiber mesh with different content and structures with that of metal mesh in complete dentures. MATERIAL AND METHODS Two types of glass fiber mesh were used: SES mesh (SES) and glass cloth (GC2, GC3, and GC4). A metal mesh was used for comparison. The complete dentures were made by placing the reinforcement 1 mm away from the tissue surface. A control group was prepared without any reinforcement (n=10). The compressive properties were measured by a universal testing machine at a crosshead speed of 5 mm/min. The results were analyzed with the Kruskal-Wallis test and the Duncan multiple range test (α=.05). RESULTS The fracture resistance of the SES group was significantly higher than that of the control, GC4, and metal groups (asymptotic P=.004), but not significantly different from the GC2 and GC3 groups. The toughness of the SES and GC3 groups was significantly higher than that of the others (asymptotic P<.001), but not significantly different from that of the GC4 group. CONCLUSIONS SES and GC3, which have different structures but similar volume content, were the most effective in reinforcing complete dentures. The content of the glass fiber mesh seemed more important than the structures.
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Affiliation(s)
- Sang-Hui Yu
- Postdoctoral Researcher, Department of Dental Biomaterials and Institute of Biomaterials-Implant, College of Dentistry and Institute of Biomaterials-Implant, Wonkwang University, Iksan, Korea
| | - Hye-Won Cho
- Professor, Department of Prosthodontics, College of Dentistry, College of Dentistry and Institute of Biomaterials-Implant, Wonkwang University, Iksan, Korea
| | - Seunghan Oh
- Associate Professor, Department of Dental Biomaterials and Institute of Biomaterials-Implant, College of Dentistry and Institute of Biomaterials-Implant, Wonkwang University, Iksan, Korea
| | - Ji-Myung Bae
- Professor, Department of Dental Biomaterials and Institute of Biomaterials-Implant, College of Dentistry and Institute of Biomaterials-Implant, Wonkwang University, Iksan, Korea.
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Wang CW, Shao Q, Sun HQ, Mao MY, Zhang XW, Gong Q, Xiao GN. Influence of inner circular sealing area impression method on the retention of complete dentures. Braz Dent J 2015; 26:198-202. [PMID: 25831114 DOI: 10.1590/0103-6440201300383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 01/27/2015] [Indexed: 11/22/2022] Open
Abstract
The aims of the present study were to describe an impression method of "inner circular sealing area" and to evaluate the effect of the method on retention, aesthetics and comfort of complete dentures, which lack labial base for patients with maxillary protrusions. Three patients were subjected to the experiment, and two sets of complete maxillary dentures were made for each patient; the first set was made without labial base via an inner circular sealing area method (experimental group) and the second had an intact base that was made with conventional methods (control group). Retention force tests were implemented with a tensile strength assessment device to assess the retention and a visual analogue scale (VAS) was used to evaluate the comfort between the two groups. Results showed larger retention force, better aesthetics and more comfort in the experimental group. The improved two-step impression method formed an inner circular sealing area that prevented damage to the peripheral border seal effect of the denture caused by incomplete bases and obtained better denture retention.
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Affiliation(s)
- Cun-Wei Wang
- College of Stomatology, Shandong University, Jinan, Shandong, People's Republic of China
| | - Qi Shao
- Weihai Municipal Hospital, Weihai, Shandong, People's Republic of China
| | - Hui-Qiang Sun
- College of Stomatology, Shandong University, Jinan, Shandong, People's Republic of China
| | - Meng-Yun Mao
- College of Stomatology, Shandong University, Jinan, Shandong, People's Republic of China
| | - Xin-Wei Zhang
- College of Stomatology, Shandong University, Jinan, Shandong, People's Republic of China
| | - Qi Gong
- College of Stomatology, Shandong University, Jinan, Shandong, People's Republic of China
| | - Guo-Ning Xiao
- College of Stomatology, Shandong University, Jinan, Shandong, People's Republic of China
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Benazzi S, Nguyen HN, Kullmer O, Hublin JJ. Exploring the biomechanics of taurodontism. J Anat 2014; 226:180-8. [PMID: 25407030 DOI: 10.1111/joa.12260] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2014] [Indexed: 01/01/2023] Open
Abstract
Taurodontism (i.e. enlarged pulp chamber with concomitant apical displacement of the root bi/trifurcation) is considered a dental anomaly with relatively low incidence in contemporary societies, but it represents a typical trait frequently found in Neandertal teeth. Four hypotheses can be envisioned to explain the high frequency in Neandertals: adaptation to a specific occlusal loading regime (biomechanical advantage), adaptation to a high attrition diet, pleiotropic or genetic drift effects. In this contribution we used finite element analysis (FEA) and advanced loading concepts based on macrowear information to evaluate whether taurodontism supplies some dental biomechanical advantages. Loads were applied to the digital model of the lower right first molar (RM1 ) of the Neandertal specimen Le Moustier 1, as well as to the digital models of both a shortened and a hyper-taurodontic version of Le Moustier RM1 . Moreover, we simulated a scenario where an object is held between teeth and pulled in different directions to investigate whether taurodontism might be useful for para-masticatory activities. Our results do not show any meaningful difference among all the simulations, pointing out that taurodontism does not improve the functional biomechanics of the tooth and does not favour para-masticatory pulling activities. Therefore, taurodontism should be considered either an adaptation to a high attrition diet or most likely the result of pleiotropic or genetic drift effects. Finally, our results have important implications for modern dentistry during endodontic treatments, as we observed that filling the pulp chamber with dentine-like material increases tooth stiffness, and ultimately tensile stresses in the crown, thus favouring tooth failure.
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Affiliation(s)
- Stefano Benazzi
- Department of Cultural Heritage, University of Bologna, Ravenna, Italy; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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Sunbuloglu E. Stress analysis of a complete maxillary denture under various drop impact conditions: a 3D finite element study. Comput Methods Biomech Biomed Engin 2014; 18:1543-54. [PMID: 24945936 DOI: 10.1080/10255842.2014.927446] [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: 10/25/2022]
Abstract
Complete maxillary dentures are one of the most economic and easy ways of treatment for edentulous patients and are still widely used. However, their survival rate is slightly above three years. It is presumed that the failure reasons are not only due to normal fatigue but also emerge from damage based on unavoidable improper usage. Failure types other than long-term fatigue, such as over-deforming, also influence the effective life span of dentures. A hypothesis is presumed, stating that the premature/unexpected failures may be initiated by impact on dentures, which can be related to dropping them on the ground or other effects such as biting crispy food. Thus, the behavior of a complete maxillary denture under impact loading due to drop on a rigid surface was investigated using the finite element method utilizing explicit time integration and a rate-sensitive elastoplastic material model of polymethylmethacrylate (PMMA). Local permanent deformations have been observed along with an emphasis on frenulum region of the denture, regardless of the point of impact. Contact stresses at the tooth-denture base were also investigated. The spread of energy within the structure via wave propagation is seen to play a critical role in this fact. Stress-wave propagation is also seen to be an important factor that decreases the denture's fatigue life.
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Affiliation(s)
- Emin Sunbuloglu
- a Faculty of Mechanical Engineering, Istanbul Technical University , Inonu Cad. No: 65, Gumussuyu, Beyoglu, Istanbul 34437 , Turkey
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27
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HASE H, SHINYA A, YOKOYAMA D, SHINYA A, TAKAHASHI Y. Three-dimensional finite element analysis of Aramany Class IV obturator prosthesis with different clasp designs. Dent Mater J 2014; 33:383-8. [DOI: 10.4012/dmj.2014-015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Cilingir A, Bilhan H, Baysal G, Sunbuloglu E, Bozdag E. The impact of frenulum height on strains in maxillary denture bases. J Adv Prosthodont 2013; 5:409-15. [PMID: 24353878 PMCID: PMC3865195 DOI: 10.4047/jap.2013.5.4.409] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 09/18/2013] [Accepted: 11/07/2013] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The midline fracture of maxillary complete dentures is a frequently encountered complication. The purpose of this study was to assess the effect of frenulum height on midline strains of maxillary complete dentures. MATERIALS AND METHODS A removable maxillary complete denture was fabricated and duplicated seven times. Four different labial frenulum heights were tested for stresses occurring on the palatal cameo surface. The strains were measured with strain gauges placed on 5 different locations and the stresses were calculated. To mimic occlusal forces bilaterally 100 N of load was applied from the premolar and molar region. RESULTS A statistically significant association between the height of the labial frenulum and the calculated stresses and strains was shown (P<.05) predominantly on the midline and especially on the incisive papilla. The results showed that stress on the anterior midline of the maxillary complete denture increases with a higher labial frenulum. CONCLUSION Within the limitations of this in vitro study, it can be concluded that the stress on the anterior midline of the maxillary complete denture increases with a higher labial frenulum. Surgical or mechanical precautions should be taken to prevent short-term failure of maxillary complete dentures due to stress concentration and low cycle fatigue tendency at the labial frenulum region.
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Affiliation(s)
- Altug Cilingir
- Istanbul University, Faculty of Dentistry, Department of Prosthodontics, Istanbul, Turkey
| | - Hakan Bilhan
- Istanbul University, Faculty of Dentistry, Department of Prosthodontics, Istanbul, Turkey
| | - Gokhan Baysal
- Istanbul Technical University, Faculty of Mechanical Engineering, Laboratory of Biomechanics, Istanbul, Turkey
| | - Emin Sunbuloglu
- Istanbul Technical University, Faculty of Mechanical Engineering, Laboratory of Biomechanics, Istanbul, Turkey
| | - Ergun Bozdag
- Istanbul Technical University, Faculty of Mechanical Engineering, Laboratory of Biomechanics, Istanbul, Turkey
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29
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Ajaj-Alkordy NM, Alsaadi MH. Elastic modulus and flexural strength comparisons of high-impact and traditional denture base acrylic resins. Saudi Dent J 2013; 26:15-8. [PMID: 24532960 DOI: 10.1016/j.sdentj.2013.12.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 11/05/2013] [Accepted: 12/03/2013] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Fractures of acrylic resin dentures are a common occurrence in clinical dentistry. The denture may be fractured accidentally when dropped or while in service in the mouth due to flexural fatigue. OBJECTIVES The aim of this study was to compare the elastic modulus and the flexural strength between two heat-cured acrylic resins used in denture bases: a high-impact resin (Lucitone 199) and a traditional resin (Rodex). MATERIALS AND METHODS Rectangular strips of Lucitone 199 and Rodex (10 samples each) were fabricated and stored in artificial saliva at 37 °C for 2 weeks. The specimens were subjected to a three-point flexural test. The data were statistically analysed with Student's t-test (p ⩽ .05). RESULTS The high-impact acrylic resin had a lower elastic modulus (p = .000) and higher flexural strength (p = .001) compared to the traditional acrylic resin. CONCLUSION Within the limitations of this study, it can be concluded that the high-impact acrylic resin is a suitable denture base material for patients with clinical fracture of the acrylic denture.
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Affiliation(s)
- Nour M Ajaj-Alkordy
- Department of Removable Prosthodontics, Faculty of Dental Medicine, Damascus University, Syria
| | - Mohannad H Alsaadi
- Department of Removable Prosthodontics, Faculty of Dental Medicine, Damascus University, Syria
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Silva CDS, Machado AL, Chaves CDAL, Pavarina AC, Vergani CE. Effect of thermal cycling on denture base and autopolymerizing reline resins. J Appl Oral Sci 2013; 21:219-24. [PMID: 23857648 PMCID: PMC3881901 DOI: 10.1590/1679-775720130061] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Accepted: 04/05/2013] [Indexed: 12/05/2022] Open
Abstract
Objective: This study evaluated the fracture toughness (FT) of denture base and autopolymerizing
reline resins, with and without thermocycling (T). Material and Methods: Specimens of each material (denture base acrylic resin - Lucitone 550 - L;
autopolymerizing reline resins - Ufi Gel Hard-UH, Tokuyama Rebase II-TR, New Truliner-
NT and Kooliner-K), were produced, notched and divided into two groups (n=10): CG
(control group of autopolymerizing reline resins and L): FT tests were performed after
polymerization; TG (thermocycled group): FT tests were performed after T (5ºC and 55ºC
for 5,000 cycles). Results: Results (MPa.m(1/2)) were analyzed by two-way ANOVA and Tukey's test
(p=0.05). L exhibited the highest FT mean values in both groups (CG - 2.33; TG - 2.17).
For the CG groups, NT showed the highest FT (1.64) among the autopolymerizing reline
resins, and K the lowest (1.04). After T, when the autopolymerizing reline resins were
compared, a statistically significant difference in FT was found only between the NT
(1.46) and TR (1.00). Conclusions: Thermocycling increased the FT of K and did not influence the FT of L, UH, TR and
NT.
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Affiliation(s)
- Cíntia de Souza Silva
- Department of Dental Materials and Prosthodontics, School of Dentistry Araraquara, Univ. Estadual Paulista, Araraquara, SP, Brazil
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Wakabayashi N, Suzuki T. Patient-specific finite element analysis of viscoelastic masticatory mucosa. JOURNAL OF DENTAL BIOMECHANICS 2013; 4:1758736013483298. [PMID: 23580171 PMCID: PMC3619231 DOI: 10.1177/1758736013483298] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The purpose of this study was to analyze the stress and strain inside of the oral mucosa in partially-edentulous patients. The patient-specific finite element models of the mucosa and the bone were constructed using the CT images and in-vivo surface measurement during a continuous load. The mean initial shear modulus of 8.3 × 10–5 (GPa) and the mean relaxation time of 503 (s) were determined as the viscoelastic properties of the mucosa. The increase of the highest maximum compressive strain during the continuous loading was observed in all the patients, however; the intensity of strain was not in accordance with the thickness of the mucosa. It is suggested that the variations of the morphology and the initial modulus of the mucosa should be considered in the mathematical approaches to detect the mechanical responses of the oral mucosa.
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Affiliation(s)
- Noriyuki Wakabayashi
- Department of Removable Partial Prosthodontics, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
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Finite element analysis of different surgical approaches in various occlusal loading locations for zygomatic implant placement for the treatment of atrophic maxillae. Int J Oral Maxillofac Surg 2012; 41:1077-89. [PMID: 22575179 DOI: 10.1016/j.ijom.2012.04.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 01/27/2012] [Accepted: 04/13/2012] [Indexed: 11/23/2022]
Abstract
The aim of this study was to compare two different types of surgical approaches, intrasinus and extramaxillary, for the placement of zygomatic implants to treat atrophic maxillae. A computational finite element simulation was used to analyze the strength of implant anchorage for both approaches in various occlusal loading locations. Three-dimensional models of the craniofacial structures surrounding a region of interest, soft tissue and framework were developed using computed tomography image datasets. The implants were modelled using computer-aided design software. The bone was assumed to be linear isotropic with a stiffness of 13.4 GPa, and the implants were assumed to be made of titanium with a stiffness of 110 GPa. Masseter forces of 300 N were applied at the zygomatic arch, and occlusal loads of 150 N were applied vertically onto the framework surface at different locations. The intrasinus approach demonstrated more satisfactory results and could be a viable treatment option. The extramaxillary approach could also be recommended as a reasonable treatment option, provided some improvements are made to address the cantilever effects seen with that approach.
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Prombonas AE, Vlissidis DS, Maria PA, Nikolas PA. The stress state of the fraenal notch region in complete upper dentures. Med Eng Phys 2012; 34:1477-82. [PMID: 22445585 DOI: 10.1016/j.medengphy.2012.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2011] [Revised: 02/10/2012] [Accepted: 02/20/2012] [Indexed: 11/28/2022]
Abstract
The present study determines the stress field in the region of the labial flange of the complete upper denture (CUD). Using commercial edentulous molds and standardized procedures eight identical CUDs were fabricated with an initial fraenal notch of 5 mm. Three addition notch conditions were produced by deepening the notch two times giving a total depth of the notch of 7 and 9 mm respectively. Finally an incisal diastema of 7 mm was created in every CUD. Three elements rosette strain gauge was cemented onto the midline of each denture specimen near the fraenal notch, for calculating the two principal stresses and the maximum shear stress. It is less possible that a failure crack in a CUD will be initiated from the region of the fraenal notch, due to the compressive nature of the principal stresses (they are varied significantly among the four notch conditions with P=0.035 for σ(1) and P=0.007 for σ(2)) and the low value of the maximum shear stress. The creation of an incisal diastema significantly decreased the values of the principal stresses σ(1) (P=0.012) and σ(2) (P=0.025). Further investigation is needed to detect the region of the CUD where a failure crack may be initiated.
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Affiliation(s)
- Anthony E Prombonas
- Department of Dental Technology, Technological and Educational Institute of Athens, Athens, Greece.
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Effects of different implant-abutment connections on micromotion and stress distribution: prediction of microgap formation. J Dent 2012; 40:467-74. [PMID: 22366313 DOI: 10.1016/j.jdent.2012.02.009] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 02/15/2012] [Accepted: 02/16/2012] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES The aim of this study was to analyse micromotion and stress distribution at the connections of implants and four types of abutments: internal hexagonal, internal octagonal, internal conical and trilobe. METHODS A three dimensional (3D) model of the left posterior mandible was reconstructed from medical datasets. Four dental implant systems were designed and analysed independently in a virtual simulation of a first molar replacement. Material properties, contact properties, physiological loading and boundary conditions were assigned to the 3D model. Statistical analysis was performed using one-way analysis of variance (ANOVA) with a 95% confidence interval and Tukey's Honestly Significant Difference (HSD) multiple comparison test. RESULTS The internal hexagonal and octagonal abutments produced similar patterns of micromotion and stress distribution due to their regular polygonal design. The internal conical abutment produced the highest magnitude of micromotion, whereas the trilobe connection showed the lowest magnitude of micromotion due to its polygonal profile. CONCLUSIONS Non-cylindrical abutments provided a stable locking mechanism that reduced micromotion, and therefore reduced the occurrence of microgaps. However, stress tends to concentrate at the vertices of abutments, which could lead to microfractures and subsequent microgap formation.
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ZHANG X, ZHANG X, ZHU B, LIN K, CHANG J. Mechanical and thermal properties of denture PMMA reinforced with silanized aluminum borate whiskers. Dent Mater J 2012. [DOI: 10.4012/dmj.2012-016] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Benazzi S, Kullmer O, Grosse IR, Weber GW. Brief communication: Comparing loading scenarios in lower first molar supporting bone structure using 3D finite element analysis. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2011; 147:128-34. [DOI: 10.1002/ajpa.21607] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 07/31/2011] [Indexed: 11/09/2022]
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Benazzi S, Kullmer O, Grosse IR, Weber GW. Using occlusal wear information and finite element analysis to investigate stress distributions in human molars. J Anat 2011; 219:259-72. [PMID: 21615398 DOI: 10.1111/j.1469-7580.2011.01396.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Simulations based on finite element analysis (FEA) have attracted increasing interest in dentistry and dental anthropology for evaluating the stress and strain distribution in teeth under occlusal loading conditions. Nonetheless, FEA is usually applied without considering changes in contacts between antagonistic teeth during the occlusal power stroke. In this contribution we show how occlusal information can be used to investigate the stress distribution with 3D FEA in lower first molars (M(1)). The antagonistic crowns M(1) and P(2)-M(1) of two dried modern human skulls were scanned by μCT in maximum intercuspation (centric occlusion) contact. A virtual analysis of the occlusal power stroke between M(1) and P(2)-M(1) was carried out in the Occlusal Fingerprint Analyser (OFA) software, and the occlusal trajectory path was recorded, while contact areas per time-step were visualized and quantified. Stress distribution of the M(1) in selected occlusal stages were analyzed in strand7, considering occlusal information taken from OFA results for individual loading direction and loading area. Our FEA results show that the stress pattern changes considerably during the power stroke, suggesting that wear facets have a crucial influence on the distribution of stress on the whole tooth. Grooves and fissures on the occlusal surface are seen as critical locations, as tensile stresses are concentrated at these features. Properly accounting for the power stroke kinematics of occluding teeth results in quite different results (less tensile stresses in the crown) than usual loading scenarios based on parallel forces to the long axis of the tooth. This leads to the conclusion that functional studies considering kinematics of teeth are important to understand biomechanics and interpret morphological adaptation of teeth.
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Affiliation(s)
- Stefano Benazzi
- Department of Anthropology, University of Vienna, Vienna, Austria.
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