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Disha V, Čelebić A, Peršić S, Papić M, Rener-Sitar K. Orofacial esthetics, chewing function, and oral health-related quality of life in Kennedy class I patients with mini-implant-retained removable partial dentures: A 3-year clinical prospective study. Clin Oral Investig 2024; 28:353. [PMID: 38825621 DOI: 10.1007/s00784-024-05741-z] [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: 12/02/2023] [Accepted: 05/24/2024] [Indexed: 06/04/2024]
Abstract
This prospective clinical study aimed to assess self-reported orofacial esthetics, chewing function, and oral health-related quality of life (OHRQoL) over three years in the Kennedy Class I patients without posterior dentition who received free-end saddle removable partial dentures (RPDs) retained by two mini dental implants (MDIs) inserted in the canine/first premolar region. The study's robust findings reaffirm the viability of MDI-retained RPDs as a treatment modality in contemporary prosthodontics, instilling confidence in the dental community. MATERIALS AND METHODS 92 participants with posterior edentulism in the maxilla or mandible received 184 MDIs and 92 RPDs. After one year, three participants were excluded, and another seven were excluded after three years. The final sample was 82 participants. Self-perceived orofacial esthetics was assessed by the Orofacial Esthetic Scale (OES), chewing function by the Chewing Function Questionnaire (CFQ), and the OHRQoL by the OHIP-14. Statistical analysis utilized multivariate regression analysis, standardized effect size calculation, Wilcoxon Signed Rank test, and Friedman's test. RESULTS OHRQoL and chewing function significantly improved (p < 0.001) one month after MDI loading by the new RPDs and continued to improve over the observation period (p < 0.05). The OES also significantly improved (p < 0.001) and remained almost unchanged over the next three years (p = 0.440). CONCLUSION Despite the limitations of this study, the MDI-retained RPD appears to be a viable treatment modality in contemporary prosthodontics from the patients' perspective.
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Affiliation(s)
- Visar Disha
- Department of Dentistry, Medical Faculty, Clinics of Prosthodontics, Pristina, Republic of Kosovo.
| | - Asja Čelebić
- Department of Prosthodontics, School of Dental Medicine, University of Zagreb, Zagreb, Croatia
| | - Sanja Peršić
- Department of Prosthodontics, School of Dental Medicine, University of Zagreb, Zagreb, Croatia
| | - Milan Papić
- Department of Quantitative Methods in Business and Economy, Libertas International University, Zagreb, Croatia
| | - Ksenija Rener-Sitar
- Department for Prosthodontics, Dental Division, Medical Faculty, University of Ljubljana, Ljubljana, Slovenia
- Department for Prosthetic Dentistry, University Dental Clinics, University Medical Center of Ljubljana, Ljubljana, Slovenia
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Luo Y, Qiu L, Geng M, Zhang W. Retention and fatigue performance of modified polyetheretherketone clasps for removable prosthesis. J Mech Behav Biomed Mater 2024; 154:106539. [PMID: 38598917 DOI: 10.1016/j.jmbbm.2024.106539] [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: 01/18/2024] [Revised: 04/01/2024] [Accepted: 04/03/2024] [Indexed: 04/12/2024]
Abstract
PURPOSE Polyetheretherketone (PEEK) is considered as an alternative to metal material for removable partial denture (RPD). However, the retentive force is not strong as a metal RPD. This study investigated the retention and fatigue performance of PEEK clasps with different proportions of clasp arm engaging the undercut to verify a new strategy to improve their clinical performance. METHODS Three groups (n = 10/group) of PEEK clasps with their terminal 1/3, 2/3 and the whole of retentive arms engaging the undercut were fabricated along with a group (n = 10) of conventional cobalt-chrome (CoCr) clasps as control group. Retentive forces were measured by universal testing machine initially and at an interval of 1500 cycles for a total of 15,000 fatigue cycles. The fatigue cycles were conducted by repeated insertion and removal of the clasp using fatigue testing machine. Each clasp was scanned by Trios3 scanner before and after fatigue test to obtain digital models. The deformation of the clasp was evaluated by root mean square (RMS) through aligning the two models in Geomagic wrap (2021). Scanning electron microscopy (SEM) and finite element analysis were carried out to observe the abrasion and the von Mises stress of the clasp arm. Kruskal-Wallis H test was used to compare the retentive forces and the RMSs of the studied groups followed by Bonferroni multiple comparisons. RESULTS The whole of PEEK clasp arm engaging the undercut provided higher mean retentive forces (7.99 ± 2.02 N) than other PEEK clasp groups (P < 0.001) and was closer to CoCr clasps (11.88 ± 2.05 N). The RMSs of PEEK clasps were lower than CoCr clasps (P < 0.05) while the differences among PEEK clasps were of no statistical significance (P > 0.05). SEM showed that evidences of surface abrasion were observed on the section that engaged the undercut for all groups of clasps. The stress concentration mainly occurred on the initial part of the retentive arm. The maximum von Mises stress of each group was below the compressive strength of PEEK. CONCLUSIONS Proportions of PEEK clasp arm engaging the undercut positively influenced the retentive force and the fatigue resistance of PEEK clasps was superior than CoCr clasps. It is a feasible method to improve the retention of PEEK clasps by increasing the proportion of clasp arm engaging the undercut. Clinical trials are needed to further verify this innovation.
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Affiliation(s)
- Yichen Luo
- Department of Oral Special Consultation, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, PR China; State Key Laboratory Cultivation Base of Research, Prevention and Treatment for Oral Diseases (Nanjing Medical University), Nanjing, PR China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, PR China
| | - Lin Qiu
- Department of Oral Special Consultation, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, PR China; State Key Laboratory Cultivation Base of Research, Prevention and Treatment for Oral Diseases (Nanjing Medical University), Nanjing, PR China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, PR China
| | - Mingzhu Geng
- Department of Oral Special Consultation, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, PR China; State Key Laboratory Cultivation Base of Research, Prevention and Treatment for Oral Diseases (Nanjing Medical University), Nanjing, PR China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, PR China
| | - Wei Zhang
- Department of Oral Special Consultation, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, PR China; State Key Laboratory Cultivation Base of Research, Prevention and Treatment for Oral Diseases (Nanjing Medical University), Nanjing, PR China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, PR China.
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Zhou Z, Shi R, Wang J, Han X, Gao W, Jiao J, Qi Y, Li Y, Zhou Y, Zhao J. Finite Element Analysis of Different Carbon Fiber Reinforced Polyetheretherketone Dental Implants in Implant-supported Fixed Denture. JOURNAL OF STOMATOLOGY, ORAL AND MAXILLOFACIAL SURGERY 2024:101902. [PMID: 38685354 DOI: 10.1016/j.jormas.2024.101902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 04/27/2024] [Indexed: 05/02/2024]
Abstract
OBJECTIVES The purpose of this study is to determine the feasibility of polyetheretherketone-based dental implants, and analyze the stress and strain around different kinds of dental implants by finite element analysis. METHODS The radiographic data was disposed to models in Mimics 19.0. 3D models of implants, crowns and jawbones were established and combined in SolidWorks 2018. Appling axial and oblique loads of 100 N, cloud pictures were exported in Ansys Workbench 18.0 to calculate and analyze the stress and strain in and around different implants. RESULTS Oblique load tended to deliver more stress to bone tissue than axial load. The uniformity of stress distribution was the best for 30% short carbon fiber reinforced polyetheretherketone implants at axial and buccolingual directions. Stress shielding phenomenon occurred at the neck of 60% continuous carbon fiber reinforced polyetheretherketone and titanium implants. Stress concentration appeared in PEEK implants and the load of bone tissue would aggravate. CONCLUSIONS 30% short carbon fiber reinforced polyetheretherketone implants demonstrate a more uniform stress distribution in bone-implant contact and surrounding bone than titanium. Stress shielding and stress concentration may be avoided in bone-implant interface and bone tissue. Bone disuse-atrophy may be inhibited in PEEK-based implants.
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Affiliation(s)
- Zhe Zhou
- Hospital of Stomatology, Jilin University, Changchun, 130021, China.
| | - Ruining Shi
- Hospital of Stomatology, Jilin University, Changchun, 130021, China.
| | - Junqi Wang
- Hospital of Stomatology, Jilin University, Changchun, 130021, China.
| | - Xiao Han
- Hospital of Stomatology, Jilin University, Changchun, 130021, China.
| | - Weijia Gao
- Hospital of Stomatology, Jilin University, Changchun, 130021, China.
| | - Junjie Jiao
- Hospital of Stomatology, Jilin University, Changchun, 130021, China.
| | - Yuanzheng Qi
- Hospital of Stomatology, Jilin University, Changchun, 130021, China.
| | - Yongli Li
- Hospital of Stomatology, Jilin University, Changchun, 130021, China.
| | - Yanmin Zhou
- Hospital of Stomatology, Jilin University, Changchun, 130021, China; Jilin Province Key Laboratory of Tooth Development and Bone Remodeling, Changchun, 130021, China.
| | - Jinghui Zhao
- Hospital of Stomatology, Jilin University, Changchun, 130021, China; Jilin Province Key Laboratory of Tooth Development and Bone Remodeling, Changchun, 130021, China.
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Alouch E, Karkoutly M, Teriaky O. Effect of various staining beverages on the color stability of CAD/CAM PMMA denture teeth: An in vitro study. Clin Exp Dent Res 2024; 10:e869. [PMID: 38433287 PMCID: PMC10909787 DOI: 10.1002/cre2.869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 01/22/2024] [Accepted: 01/31/2024] [Indexed: 03/05/2024] Open
Abstract
OBJECTIVE This study aimed to compare the color change of computer-aided design (CAD)/computer-aided manufacturing (CAM) polymethyl methacrylate (PMMA) denture teeth and conventional acrylic teeth after immersion in three staining beverages (coffee, red tea, and cola) for a day, 7 days, and 30 days. MATERIALS AND METHODS Group 1: Conventional acrylic teeth (n = 32). Group 2: Milled CAD/CAM teeth out of PMMA disc (n = 32). The specimens of each material were further divided into four subgroups: (1) Control group, distilled water (n = 16). (2) Red tea solution (n = 16). (3) Coffee solution (n = 16). (4) Cola (n = 16). The color change (∆ E $\unicode{x02206}E$ ) was assessed using a spectrophotometer at four time points: at the baseline (t0 ), on the 1st day (t1 ), on the 7th day (t2 ), and the 30th day (t3 ) of immersion. Kolmogorov-Smirnov test was applied, followed by performing independent samples t test, one-way analysis of variance and post-hoc Tukey tests to compare the color change values at different time points. RESULTS The mean score of NBS values of the coffee solution indicates perceivable color change at the end of the 30th day in the conventional acrylic teeth group. It was 0.843 ± 0.395 at t1 , then increased to 1.017 ± 0.477 at t2 and to 2.259 ± 1.059 at t3 . There is a statistically significant difference (p < 0.05) in color change values between both tooth types at the end of the 30th day of immersion in red tea solution and a statistically significant difference at the end of the 7th day (p < 0.05) and the 30th day (p < 0.05) of immersion in coffee solution. CONCLUSIONS CAD/CAM PMMA teeth are more color stable than conventional acrylic teeth after 30 days of immersion in coffee and red tea solution.
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Affiliation(s)
- Ehab Alouch
- Department of Removable ProsthodonticsDamascus UniversityDamascusSyrian Arab Republic
| | - Mawia Karkoutly
- Department of Pediatric DentistryDamascus UniversityDamascusSyrian Arab Republic
| | - Omar Teriaky
- Department of Removable ProsthodonticsDamascus UniversityDamascusSyrian Arab Republic
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Fahmy MM, Al-Afandy MH, Mohamed HT, Abdelfattah Mohamed AM. Effect of different framework materials on stresses induced in distal extension removable partial dentures: A strain gauge analysis. J Prosthodont 2024. [PMID: 38520400 DOI: 10.1111/jopr.13847] [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: 10/21/2023] [Accepted: 03/07/2024] [Indexed: 03/25/2024] Open
Abstract
PURPOSE Evaluation of the strain transmitted to the abutments and residual ridge by polyetherketoneketone material compared to the cobalt-chromium one in distal extension removable partial dentures (RPDs) to fulfill the objective of preservation of the supporting structures. MATERIALS AND METHODS A virtual model simulating a Kennedy class I partially edentulous mandibular arch was designed. Two models, one for each group, were printed. Five RPDs were made in each group. In group CR, the framework was milled from a cobalt-chromium alloy. While in group PK, it was milled from a polyetherketoneketone blank. Strain gauge rosettes were bonded distal to the last abutment and posteriorly in the distal end of the residual ridge. Unilateral vertical and oblique loadings were applied. Mann-Whitney U test was used for inter-group comparisons while the Friedman test was used for intra-group comparisons and corrected by Wilcoxon Signed-Rank Sum. The significance level was set at p ≤ 0.05. RESULTS During unilateral vertical load application, a statistically significant difference was found between both groups distal to the abutment in the loaded and unloaded sides as well as the residual ridge on the unloaded side. During oblique load application, a statistically significant difference was found between both groups in all slots. CONCLUSION Polyetherketoneketone material induces less stress on the abutments and more stress on the residual ridges compared to the cobalt-chromium ones. Therefore, it may be recommended for weak abutments supporting RPDs.
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Affiliation(s)
- Maha Mahmoud Fahmy
- Oral and Maxillofacial Prosthodontics Department, Faculty of Dentistry, Ain-Shams University, Cairo, Egypt
| | - Mahmoud Hassan Al-Afandy
- Oral and Maxillofacial Prosthodontics Department, Faculty of Dentistry, Ain-Shams University, Cairo, Egypt
| | - Hebatallah Tarek Mohamed
- Oral and Maxillofacial Prosthodontics Department, Faculty of Dentistry, Ain-Shams University, Cairo, Egypt
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Kuroshima S, Ohta Y, Uto Y, Al-Omari FA, Sasaki M, Sawase T. Implant-assisted removable partial dentures: Part I. a scoping review of clinical applications. J Prosthodont Res 2024; 68:20-39. [PMID: 37164658 DOI: 10.2186/jpr.jpr_d_22_00252] [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: 05/12/2023]
Abstract
PURPOSE This scoping review aimed to systematically map research regarding implant-assisted removable partial dentures (IARPDs), and identify existing gaps in knowledge. STUDY SELECTION Two reviewers independently conducted a search of the MEDLINE-PubMed and Scopus databases according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) extension for Scoping Review and included articles published in English up to August 31, 2022, including human studies, reviews, and in vitro studies. Expert opinions, animal studies, and clinical studies involving complete overdentures were excluded, and ten aspects for establishing the treatment strategy for IARPDs were examined. RESULTS One hundred and twelve articles were chosen. There were two treatment modalities: IARPDs retained by implant- and tooth-supported surveyed single crowns (SCs) or fixed partial dentures (FPDs). In IARPDs retained by tooth-supported surveyed SCs or FPDs, the survival rate of dental implants for IARPDs was relatively higher with a wide range of marginal bone loss and many complications, but with improved functional performance, oral health-related quality of life, and patient satisfaction. There were limited data on survival or success rates and designs of IARPDs, attachment selections, length and diameter, inclination, placement sites, and loading protocols of implants, regardless of prosthetic types. There was limited information on maxillary IARPDs except for survival rates of implants. CONCLUSIONS Although IARPDs could become a useful treatment strategy, there is limited scientific consensus with gaps in knowledge about their use. Additional well-designed clinical and in vitro studies are necessary to scientifically establish IARPDs as definitive prostheses in implant dentistry.
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Affiliation(s)
- Shinichiro Kuroshima
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Yoshikazu Ohta
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Yusuke Uto
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Farah A Al-Omari
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Muneteru Sasaki
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Takashi Sawase
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
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Zhang Y, Zheng X, Zhang Q, He Z, Huang W, Yan X, Lv T, Yuan X. Clinical finite element analysis of mandibular displacement model treated with Twin-block appliance. Am J Orthod Dentofacial Orthop 2023; 164:395-405. [PMID: 37029052 DOI: 10.1016/j.ajodo.2023.02.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 02/01/2023] [Accepted: 02/01/2023] [Indexed: 04/09/2023]
Abstract
INTRODUCTION The mechanical distribution of the mandible is an important factor that affects functional orthosis during Twin-block (TB) appliance correction. Changes in the mandible before and after TB appliance correction are also key factors in maintaining the therapeutic effect. Finite element analysis, a powerful numerical, analytical tool, is widely used to predict the stress and strain distribution of the craniofacial bone that orthodontics generates. METHODS The sample was a 14-year-old male patient with Class II malocclusion during growth. A cone-beam computed tomography scan was undertaken at pretreatment and posttreatment. In the Finite element analysis of the pretreatment model, the remote displacement model of the mandible was established with the sella point as the center. A mandibular model under TB appliance loading was established. Its mandibular displacement and von Mises stress were compared before and after loading. Three-dimensional registration was conducted on the pretreatment and posttreatment models to measure the sagittal displacement of the centrosome. RESULTS The force on the mandible occurred mainly in the condyle neck and medial mandible after the TB appliance moved the mandible. After displacement, the posterior upper margin of the condyle was farther away from the articular fossa. Three-dimensional registration results showed that new bone had formed behind and above the condyle after TB appliance treatment. CONCLUSION The TB appliance provides additional advantages in treating skeletal Class II malocclusions by helping to reduce the burden on the temporomandibular joint and promoting the adaptive reconstruction of the mandible.
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Affiliation(s)
- Yingyue Zhang
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, China; School of Stomatology, Qingdao University, Qingdao, China
| | - Xinyu Zheng
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, China; School of Stomatology, Qingdao University, Qingdao, China
| | - Qiang Zhang
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, China; School of Stomatology, Qingdao University, Qingdao, China
| | - Zijing He
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, China; School of Stomatology, Qingdao University, Qingdao, China
| | - Wenli Huang
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, China; School of Stomatology, Qingdao University, Qingdao, China
| | - Xiao Yan
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, China; School of Stomatology, Qingdao University, Qingdao, China
| | - Tao Lv
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Qingdao, China.
| | - Xiao Yuan
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, China; School of Stomatology, Qingdao University, Qingdao, China.
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Mini-Implants Retaining Removable Partial Dentures in Subjects without Posterior Teeth: A 5-Year Prospective Study Comparing the Maxilla and the Mandible. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:medicina59020237. [PMID: 36837439 PMCID: PMC9959138 DOI: 10.3390/medicina59020237] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/20/2023] [Accepted: 01/22/2023] [Indexed: 01/31/2023]
Abstract
Background and objectives: Long-term studies of clinical outcomes of mini-implants (MDIs) in the first premolar/canine sites retaining a bilateral free-ending removable partial dentures (RPD) in Kennedy class I subjects have not been well documented. The aim was to assess clinical outcomes in a prospective 5-year cohort study comparing the mandible and maxilla. Material and Methods: Participants (n = 92) who received two MDIs each and a new RPD were reviewed after one, three and five years. A total of 71 participants (82 mini-implants in the mandible; 58 in the maxilla) completed the study. Marginal bone level change, success, survival rates, Modified Plaque (MPI) and Bleeding Indices (MBI) were assessed. Results: The five-year success rate was 93.3% and 93.4% (p > 0.05), in the mandible and the maxilla, respectively. Mean peri-implant bone loss (MBL) increased significantly over five years (p < 0.01) to 0.50 mm in the mandible and 0.52 mm in the maxilla. Age had a significant effect on the MBL (higher rates in younger participants), while jaw of insertion, gender, and antagonistic jaw status did not. MPI and MBI were not significantly correlated with MBL. Conclusions: The insertion of two MDIs in previous first premolar/canine sites for retention of a free-end saddle RPD can be a successful treatment modality in subjects with narrow alveolar ridges.
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Ajaj AL-Kordy NM, AL-Saadi MH. Finite Element Study of Stress Distribution with Tooth-Supported Mandibular Overdenture Retained by Ball Attachments or Resilient Telescopic Crowns. Eur J Dent 2022. [DOI: 10.1055/s-0042-1749363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract
Objective The removable partial denture must keep health of the remaining teeth and the supporting tissues through the distribution of chewing forces on the abutment teeth and alveolar process.This study aimed to evaluate stress distribution with canines-supported mandibular overdenture retained by two different attachment types: ball attachments or resilient telescopic crowns.
Materials and Methods Two 3-dimensional finite element models consisting of the cortical mandible bone, cancellous mandible bone, oral mucosa, canines, periodontal ligaments, the two attachment types, and overdenture were simulated. The models were imported into the mathematical analysis software Ansys Workbench V 15.0. All materials were considered to be homogeneous, isotropic, and linearly elastic. A vertical bilateral load of 120 N was applied to the central fossa of the first molars. The von Mises stress was calculated for canines, cortical, and cancellous bone.
Results The maximum von Mises stress of the ball attachments model was 35.61, 4.28, 7.82, and 1.29 MPa for canines, cortical alveolar bone of canines, cortical alveolar bone at the distal end of the overdenture, and cancellous alveolar bone of canines, respectively. The maximum von Mises stress of the resilient telescopic crowns model was 39.22, 4.74, 7.06, and 1.05 MPa for canines, cortical alveolar bone of canines, cortical alveolar bone at the distal end of the overdenture, and cancellous alveolar bone of canines, respectively.
Conclusion Resilient telescopic crowns distribute the stresses between canines, alveolar bone of canines, and overdenture supporting alveolar bone. Ball attachments transfer less stress to the canines and cortical alveolar bone of the canines, but more stress to the cancellous alveolar bone of canines and alveolar bone at distal end of the overdenture. Resilient telescopic crowns are preferred over ball attachment when the abutment teeth have good periodontal support.
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Affiliation(s)
- Nour M.T. Ajaj AL-Kordy
- Department of Removable Prosthodontics, Faculty of Dental Medicine, Damascus University, Damascus, Syria
| | - Mohannad H. AL-Saadi
- Department of Removable Prosthodontics, Faculty of Dental Medicine, Damascus University, Damascus, Syria
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Performance of Graphene-Based and Polyether-Ether-Ketone Polymers as Removable Partial Denture Esthetic Clasp Materials after Cyclic Fatigue. Polymers (Basel) 2022; 14:polym14152987. [PMID: 35893952 PMCID: PMC9331630 DOI: 10.3390/polym14152987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 11/17/2022] Open
Abstract
The esthetic clasp material is a clinical demand for a satisfactory removable partial denture. The purpose of this study is to assess the mechanical performance of graphene-based polymer (GBP) and polyether-ether-ketone (PEEK) materials as clasp materials. Thirty-two clasps were fabricated by CAD-CAM from two materials, GBP and PEEK. All clasps were tested for retention force after 10,000 cycles of insertion and removal and thermocycling. The clasp arms’ deformation was measured, and areas of stress−strain concentration were explored. The Mann−Whitney U test was used to compare the retentive force of the studied groups, while the independent sample t-test was applied to check the difference in clasp arm deformation at α = 0.5. The results showed a significantly higher retentive force (2.248 ± 0.315 N) in PEEK clasps, at p < 0.001. The deformation of the clasp arm of the GBP clasps was significantly higher than PEEK clasps. Areas of stress−strain concentration were seen at the junction of the retentive arm to the minor connector and at the retentive arm terminal. It could be concluded that PEEK polymer had a better mechanical performance as an esthetic clasp material than the GBP. An optimization study for GBP might be required to check the validity of such an application.
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Finite Element Comparative Analysis of Von Mises Stress Levels in Unilateral Removable Partial Denture with and without Distal Implant. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12105116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim of this paper is to compare von Mises stress levels and displacements between two possible designs of a class II Kennedy unilateral removable partial denture. Finite element analysis was used to compare two unilateral class II Kennedy removable partial dentures replacing a mandibular second premolar, and first and second molars and with the same design, except a distal implant. The 3D model was created for a mandibular RPD with three artificial teeth and double ball attachment on the abutment teeth and a horizontal ball attachment for the implant, using Autodesk Inventor 2022 software. On the saddle, significant differences appear only when force is applied on the second molar. Association with implant increases von Mises stresses on the acrylic saddle, where displacements values are similar, and decreases von Mises stresses on the muco-osseous support, where displacements values are also similar. Regarding metal reinforcement of the denture, von Mises stress values are greater for forces applied on the second premolar in the implant situation, and smaller for forces applied on the first and second molars. Association with implant decreases von Mises stresses on the metal reinforcement of the denture only if the force is applied distally, on the two molars; in this case, the metal reinforcement is more stressed above the mesial double ball attachment, where displacements values are similar. Regarding the artificial teeth, adding a distal implant does not significantly influence the stress and displacements values, except on the second premolar where the von Mises stresses values are greater, where displacements values are similar. Although an association with an implant increases the risk of fracture for the denture, the results demonstrate that in the posterior area of the edentulous space, the denture exerts less pressure on the mucosa and subjacent bone, protecting the area against resorption.
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Lyu H, Murakami N, Yamazaki T, Wada J, Utsumi M, Wakabayashi N. Evaluation of PEEK and zirconia occlusal rest designs for removable partial dentures based on finite element analysis. J Prosthodont Res 2022; 67:196-205. [PMID: 35644568 DOI: 10.2186/jpr.jpr_d_22_00011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Purpose We aimed to assess removable partial denture occlusal rests composed of polyether-ether-ketone (PEEK) and zirconia, using finite element analysis.Methods Three-dimensional PEEK and zirconia rest models, including the occlusal rest (1.5 mm thickness at the basal portion, 3.0 mm width) and minor connector (1.5 mm thickness, 6.0 mm height), and rest seat models with mechanical properties of enamel were constructed. The radius of transitional curvature between the rest and minor connector was 0.1-0.5 mm. The rest and rest seat model interfaces were set as frictional contacts (μ = 0.1), and the base of the rest seat model was restrained in all the directions. A 100 N downward load was applied perpendicular to the bottom surface of the minor connector. The maximum value of the first principal stress (Max-S1) was compared to the flexural and fatigue strengths of each material. Occlusal rests with 1.0-2.0 mm thickness, 2.0-3.5 mm width, and 0.5 mm radius of transitional curvature were analyzed.Results Max-S1 was observed at the transitional part and decreased with increasing radius of the transitional curvature, rest width, and thickness. PEEK rests with at least 1.5 mm thicknesses and 3.0 mm widths showed lower Max-S1 than the flexural strength. Max-S1 of all PEEK rests exceeded the PEEK fatigue strength, whereas Max-S1 of the zirconia rests was lower than the zirconia fatigue strength.Conclusions Zirconia occlusal rests with conventional metal rest designs have sufficient fatigue strength. PEEK occlusal rests have insufficient fatigue strength and may not withstand repeated mastication.
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Affiliation(s)
- Huaxin Lyu
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Natsuko Murakami
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Toshiki Yamazaki
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Junichiro Wada
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Miona Utsumi
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Noriyuki Wakabayashi
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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