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Objectives: This retrospective study aimed to investigate the differences in tooth loss rate between fixed implant-supported prostheses (FISPs) and removable partial dentures (RPDs) in cases of unilateral free-end missing teeth., Materials and Methods: The data of 324 patients who underwent treatment with FISPs or RPDs for unilateral free-end missing teeth and satisfied the applicable criteria, were evaluated (47 in the FISPs group and 277 in the RPDs group). After propensity score (PS) matching, which was used to extract patients with similar background factors related to prosthetic selection at baseline, survival time analyses were performed with tooth loss as the endpoint. The adjusted variables were age, sex, number of restored teeth, periodontal status, and the practicing dentist's experience in years. The remaining teeth were classified into subcategories in relation to the missing molars., Results: Overall, 58 patients (29 in each group) selected by PS matching were evaluated in the final analysis. The total number of lost teeth was 35 (FISPs group: n = 10; RPDs group: n = 25). The mean (±SD) period to tooth loss and the 10-year survival rates in the FISPs and RPDs groups were 51.6 (±30.1) months and 42.3 (±29.7) months, 70.5% and 16.4%, respectively. The log-rank test showed that significantly longer survival time in FISPs compared with RPDs., Conclusions: After adjustments for confounding factors using PS matching, replacing unilateral free-end missing teeth with FISPs may exhibit a lower tooth loss rate in adjacent and contralateral teeth compared to replacing with RPDs., (© 2024 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.)

Purpose: To determine the influence of partial edentulous distal extension and the use of removable partial dental prostheses in partially edentulous areas on the force exerted on the anterior teeth., Materials and Methods: A total of 83 volunteer patients participated in this study. The occlusal force was measured using an occlusal force measuring sheet in the patient's mouth. The occlusal forces and ratios were compared using the Wilcoxon signed-rank test (P < .05)., Results: The force exerted on the anterior teeth increased significantly as the number of remaining teeth decreased in an edentulous distal extension. The force exerted on the anterior teeth decreased significantly with the use of a removable partial dental prosthesis., Conclusions: In a clinical setting, when the number of remaining teeth in a partial edentulous distal extension decreases, the burden on the anterior teeth increases. Our findings suggest that, for patients with partial edentulous distal extension, using a removable partial dental prosthesis is effective in preserving the residual anterior teeth by reducing excessive force.

Purpose This study aimed to determine the influence of mandibular free-end partial edentulism and use of conventional or implant-supported removable dental prostheses in the partially edentulous area on the load exerted on the maxillary anterior teeth.Methods A jaw model with mandibular free-end missing teeth was used, and a distal extension, removable partial dental prosthesis was fabricated to replace the missing posterior teeth. Four experimental conditions were set up: 1) without prosthesis, 2) with a conventional removable partial dental prosthesis, 3) with an implant-supported removable partial dental prosthesis, and 4) with a complete dental arch. Strain gauges were attached to the root surface of the maxillary left central incisor, canine, first premolar, and first molar. The load exerted on them was calculated based on the calibration coefficient. An occlusal load of 49 N was applied, and the forces were compared using a Kruskal-Wallis test (P < 0.05). Results The load exerted on the maxillary anterior teeth increased significantly with no prosthesis, decreased significantly with a conventional removable partial dental prosthesis, and decreased even more significantly with an implant-supported removable partial dental prosthesis. Conclusions The burden on the maxillary anterior teeth decreased with the use of a removable partial dental prosthesis and decreased even further with the use of an implant-supported dental prosthesis. The use of an implant to support a distal extension removable partial dental prosthesis is potentially effective in preserving the remaining teeth and tissues by reducing excessive stress in patients with mandibular free-end partial edentulism.

Purpose: The purpose of this study was to develop a method for classifying dental arches using a convolutional neural network (CNN) as the first step in a system for designing removable partial dentures., Methods: Using 1184 images of dental arches (maxilla: 748 images; mandible: 436 images), arches were classified into four arch types: edentulous, intact dentition, arches with posterior tooth loss, and arches with bounded edentulous space. A CNN method to classify images was developed using Tensorflow and Keras deep learning libraries. After completion of the learning procedure, the diagnostic accuracy, precision, recall, F-measure and area under the curve (AUC) for each jaw were calculated for diagnostic performance of learning. The classification was also predicted using other images, and percentages of correct predictions (PCPs) were calculated. The PCPs were compared with the Kruskal-Wallis test (p = 0.05)., Results: The diagnostic accuracy was 99.5% for the maxilla and 99.7% for the mandible. The precision, recall, and F-measure for both jaws were 0.25, 1.0 and 0.4, respectively. The AUC was 0.99 for the maxilla and 0.98 for the mandible. The PCPs of the classifications were more than 95% for all types of dental arch. There were no significant differences among the four types of dental arches in the mandible., Conclusions: The results of this study suggest that dental arches can be classified and predicted using a CNN. Future development of systems for designing removable partial dentures will be made possible using this and other AI technologies.

Purpose: The purpose of this study was to determine the influence of mandibular free-end partial edentulism and the wearing of removable partial dentures in the partially edentulous area on the force exerted on maxillary anterior teeth., Methods: A commercially available jaw model with exchangeable teeth was used. Seven experimental conditions of mandibular free-end edentulism were set up and a distal extension removable partial denture to replace missing posterior teeth was fabricated. Strain gauges were attached to the root surface of the maxillary left central incisor, canine, first premolar and first molar, and the force exerted on them was calculated based on the calibration coefficient. An occlusal load of 49 N was applied and the forces were compared with the Kruskal-Wallis test (P < 0.05)., Results: The force exerted on the maxillary anterior teeth increased significantly as the number of remaining teeth decreased. The force exerted on the maxillary anterior teeth decreased significantly with use of a removable partial denture., Conclusions: When the number of remaining teeth decreases in mandibular free-end partial edentulism, the burden on the maxillary anterior teeth increases. Our findings suggest that for patients with mandibular free-end partial edentulism, wearing a removable partial denture is effective in preserving the remaining teeth by reducing excessive stress., Competing Interests: Declaration of Competing Interest None., (Copyright © 2019. Published by Elsevier Ltd.)

Purpose: This study evaluated the impact of angled abutments on strain in implants supporting a distal extension removable partial denture., Materials and Methods: An in vitro model of an implant supporting a distal extension removable partial denture was developed. The implant was positioned with a 17- or 30-degree mesial inclination, with either a healing abutment or a corrective multiunit abutment. Levels of strain under load were compared, and the results were compared using t test (P = .05)., Results: Correcting angulation with a multiunit angled abutment significantly decreased strain (P < .05) when compared with a healing abutment., Conclusion: An angled abutment decreased the strain on an inclined implant significantly more than a healing abutment when loaded under a distal extension removable partial denture.

Purpose: Root fracture is a common and serious cause of abutment tooth loss. No studies to date have comprehensively assessed the individual contributions of the factors that increase stress on abutment teeth. The purpose of this study was to analyze the stress distribution in abutment teeth based on a three-dimensional finite element model and to analyze the factors that affect stress distribution., Materials and Methods: Models were generated from the computed tomography data of a single patient, consisting of a mandibular second premolar abutment tooth, bone, residual mucous membrane, and a partial removable dental prosthesis (PRDP). Four models were prepared using different types of endodontic posts and cores. Akers clasps were used for the simulated PRDPs, and a vertical load was applied to the occlusal surface of the PRDPs. Debonding between the post and root was simulated. The Young modulus of the residual ridge was reduced to simulate a poor fit between the denture base and the residual ridge. Stress distribution in the abutment tooth root was observed, and the maximum principal stress was evaluated., Results: The nonmetal post model and the mesial rest model reduced stress concentration in the root. The stress increased in models simulating debonding and poor fit. The results of the multiple linear regression analysis confirmed that debonding and poor fit were significantly associated with root stress., Conclusion: Within the limitations of this study, it is suggested that the bonding integrity of posts and adequate fit of the denture base are important factors affecting the longevity of abutment teeth for PRDPs.

Purpose: The aim of this study was to investigate strain on implants used for adjunctive support of distal extension removable partial dentures., Materials and Methods: An implant with strain gauges was used for testing purposes in two positions, parallel and inclined. Three loading scenarios--loading apparatus (LA), artificial teeth via cotton roll (CR), and artificial teeth (UT)--were studied and strains compared via the Kruskal-Wallis test (P=.05)., Results: Strain under CR was significantly larger than UT in parallel (P<.05). However, the opposite was observed in inclined., Conclusions: Strain in parallel was smallest for UT, whereas in inclined it was largest for CR.

Purpose: The purpose of this study was to determine the implant stress under distalextension removable prostheses (DERPs)., Materials and Methods: A mandibular distal-extension cast and denture were fabricated. Strain gauges were attached to the implant, which was placed either parallel to the distal abutment or perpendicular to the ridge crest (inclined). Occlusal load was applied in five directions, and strains were compared using the Kruskal-Wallis test (P = .05)., Results: When the implant was parallel, the strain was maximum at 20 degrees applied load direction. When the implant was inclined, the strain was minimum at 20 degrees mesial and maximum at 20 degrees applied distal load direction., Conclusions: Implant bending strain is reduced when the implant is loaded on its long axis and oriented parallel with the long axis of the most distal tooth.

Statement of Problem: Conventional magnetic attachments have rigid assemblies and are unable to compensate for the movement of the prosthesis under function, which may result in the deepening of periodontal pockets and an increase in the mobility of abutment teeth., Purpose: The purpose of this study was to evaluate the clinical performance and satisfaction of participants with removable prostheses with self-adjusting magnetic attachments that allow vertical and rotational movement., Material and Methods: The clinical performance of 17 prostheses with 22 self-adjusting magnetic attachments in 16 participants was analyzed for a mean of 3.1 years. Periodontal indices, including probing pocket depth and tooth mobility, were measured at denture placement (baseline) and from 0.5 to 5 years after insertion. Control data were obtained from the remaining teeth, which were restored by resin or metal coping. Prosthetic parameters, including the reduction of retention in self-adjusting magnetic attachments, reline, or fracture of dentures, were also recorded. A visual analog scale questionnaire on participant satisfaction with stability, comfort, and cleaning of the prostheses was completed. The Wilcoxon signed rank test and 1-way analysis of variance (α=.05) were performed on data collected at the time of prostheses placement and final follow-up evaluation., Results: No significant differences were found in terms of probing pocket depth and tooth mobility between the baseline and postinsertion data for self-adjusting magnetic attachments and control teeth. Retention in all prostheses was stable, without reduction. Higher visual analog scale scores for "easy cleaning" were noted., Conclusions: No significant difference between baseline and postinsertion was noted regarding the periodontal condition of self-adjusting magnetic attachments and control teeth with resin or metal coping materials., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)