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Key Clinical Message: The treatment method of placing a small number of implants in the mandible as a removable implant‐supported overdenture (IOD) enables implant placement and denture stability, even in cases with severe residual ridge resorption. In this case report, a new implant placement technique was performed using a three‐dimensionally (3D)‐printed duplicate denture fabricated by a 3D printer, resulting in the restoration of masticatory function through IOD. [ABSTRACT FROM AUTHOR]

Key Clinical Message The treatment method of placing a small number of implants in the mandible as a removable implant‐supported overdenture (IOD) enables implant placement and denture stability, even in cases with severe residual ridge resorption. In this case report, a new implant placement technique was performed using a three‐dimensionally (3D)‐printed duplicate denture fabricated by a 3D printer, resulting in the restoration of masticatory function through IOD.

PURPOSE. The objectives of the current study were to estimate the influence of self-reinforced hollow structures with a graded density on the dimensional accuracy, weight, and mechanical properties of Co-Cr objects printed with the direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS. Sixty-five dog-bone samples were manufactured to evaluate the dimensional accuracy of printing, weight, and tensile properties of DMLS printed Co-Cr. They were divided into Group 1 (control) (n = 5), Group 2, 3, and 4 with incorporated hollow structures based on (spherical, elliptical, and diamond) shapes; they were subdivided into subgroups (n = 5) according to the volumetric reduction (10%, 15%, 20% and 25%). Radiographic imaging and microscopic analysis of the fractographs were conducted to validate the created geometries; the dimensional accuracy, weight, yield tensile strength, and modulus of elasticity were calculated. The data were estimated by one-way ANOVA and Duncan's tests at P < .05. RESULTS. The accuracy test showed an insignificant difference in the x, y, z directions in all printed groups. The weight was significantly reduced proportionally to the reduced volume fraction. The yield strength and elastic modulus of the control group and Group 2 at 10% volume reduction were comparable and significantly higher than the other subgroups. CONCLUSION. The printing accuracy was not affected by the presence or type of the hollow geometry. The weight of Group 2 at 10% reduction was significantly lower than that of the control group. The yield strength and elastic modulus of the Group 2 at a 10% reduction showed means equivalent to the compact objects and were significantly higher than other subgroups. [ABSTRACT FROM AUTHOR]

Objective: Digitally‐designed removable complete dentures are typically composed of a resin denture base without a metal framework. However, metal denture bases are preferable as resin bases are more susceptible to fracture. Therefore, this article introduces a unique technique that integrates computer‐aided design (CAD) and conventional resin processing for the fabrication of removable complete dentures with a metal framework. Clinical Consideration s : A maxillary complete denture with a metal base and a mandibular implant‐retained overdenture reinforced with a metal framework were fabricated. The dentures were designed using CAD software and a tooth library. The denture bases were milled from wax disks, and artificial teeth were placed to complete the wax dentures. The metal frameworks were also designed using CAD software and produced via casting of printed resin patterns. Finally, conventional denture processing techniques were applied to obtain dentures with metal frameworks. Conclusions: A digitally designed, removable complete denture with a metal base can be successfully fabricated using the described technique, which merges digital design and conventional methods. This article demonstrates the feasibility and potential advantages of this innovative approach in denture fabrication. Clinical Significance: The presented technique provides the following advantages: digital design features, precise space above implant overdenture attachments for a metal framework, convenience of esthetic evaluation with printed trial dentures, long‐term data storage and duplication, reliable bond between the artificial teeth and denture base, and enhanced strength of the removable complete denture due to the metal reinforcement. [ABSTRACT FROM AUTHOR]

Summary: Losing an anterior tooth could be extremely devastating for the patient and to address the psychological and emotional trauma of the patient, quick replacement is crucial. A contemporary conservative choice is a Fiber-Reinforced composite bridge. The current case report describes the fractured permanent mandibular left lateral incisor which needed to be extracted followed by the replacement of the same natural tooth crown as a pontic using Fiber-reinforced composite (Ribbond). The results were satisfying to the patient, both aesthetically and functionally. Long-term follow-up studies are needed to further evaluate this treatment option in the future. [ABSTRACT FROM AUTHOR]

Introduction: The daily practice shows that the patients prefer treatments that require fewer visits and low cost. The technology of conventional complete dentures follows several subsequent stages – clinical and laboratory. The search for alternative methods has led to the more and more successful development of digital technologies that could also be used for complete dentures. The conclusions of their use include higher quality, simplification of the laboratory technologies, and creation of functionally fit prosthetic structures. Purpose: The purpose of this research is to systematically review the up-to-date information available in the scientific databases in regard to the implementation of CAD/CAM technologies for the complete prosthesis. Materials and methods: A search was carried out in the period from January 2022 to October 2022 in the electronic databases PubMed, Google Scholar and ScienceDirect, using the following keywords: CAD/CAM, digital prosthesis, complete dentures, planning of complete dentures, edentulous patients, in English, German, Turkish and Bulgarian language. Conclusion: The individual anatomic and morphological particularities, age and functional changes occurring after the complete loss of teeth create conditions for the prosthesis that cannot be unified according to the scientific literature. Most probably, this is the reason why there is no straight protocol and straight technology for producing complete dentures using the digital method.

Purpose: Removable partial dentures have a wide range of applications as missing tooth prostheses, and the denture design can be quite diverse. However, the factors affecting masticatory function remain unclear. We investigated the effect of denture design, especially the use of indirect retainers and major connectors, on masticatory function in patients with mandibular bilateral distal extension dentures. Methods: Fifty-three patients with mandibular Kennedy Class I and Eichner classification B occlusal support were included in this study. Masticatory performance (MP) was assessed using gummy jelly. For the dentures, the type of major connector (bar or apron), presence or absence of indirect retainers, number of rests, and number of artificial teeth were evaluated. The number of functional teeth and occlusal support, Eichner classification, maxillary denture usage, mandibular residual ridge height, and duration of denture use were also evaluated. The factors influencing on the MP were evaluated using the Mann-Whitney U test, Spearman's correlation coefficient, and logistic regression analysis. Results: MP was significantly higher when the major connector was bar-type or when there was an indirect retainer than with an apron-type or no indirect retainer. MP was positively correlated with the number of functional teeth, occlusal support, and number of rests. Logistic regression analysis revealed that the number of functional teeth and the presence or absence of an indirect retainer were factors that significantly influenced the MP. Conclusions: An indirect retainer setting is useful for achieving good masticatory performance in mandibular bilateral distal extension dentures. [ABSTRACT FROM AUTHOR]

The purpose of this clinical report was to describe the use of a piezographic impression associated with computer‐aided design and computer‐aided manufacturing (CAD–CAM) for teeth setup and of digital tools for neuro‐musculo–kinetic analyses. An edentulous patient with hemiglossectomy and heavily resorbed mandible consulted for complete denture rehabilitation to improve their masticatory function and speech. Master casts, wax rims, and piezographic impression were scanned for digital prosthetic work. Two digital try‐ins were performed to respect the neutral zone: try‐in 1 with posterior crossbite and try‐in 2 without crossbite. Muscle activity and mandibular kinetics were performed for each try‐in following the MAC2 protocol (six criteria): muscular tone, contraction synchrony, contraction efficiency, interocclusal rest distance, amplitude of mandibular movement, and velocity. Try‐in 2 showed better data than try‐in 1 in all criteria: muscle tone (respectively 71% vs. 59%), contraction synchrony (79% vs. 75%), contraction efficiency (85% vs. 77%), an increase in range of motion of 3.3 mm, and a better velocity (0.35 ± 0.12 s vs. 0.57 ± 0.14 s, p = 0.008). The piezographic impression, in combination with CAD–CAM, allowed the comparison of two prosthetic designs and the selection of the try‐in with the best neuro‐musculo–kinetic results. [ABSTRACT FROM AUTHOR]

Background: Treatment of edentulous patients with implant‐supported over‐dentures improves denture's retention and stability. Published data concerning implant‐supported overdenture with cantilever bars that claimed that can affect the survival and bone loss of implants are scarce. Purpose: The purpose of this study was to evaluate 5‐year clinical performance of mandibular implant‐supported over‐dentures with different attachment systems. Materials and methods: In this retrospective study, 103 patients who had received mandibular over‐dentures supported by two implants were evaluated in a 5‐year follow up. Studied groups were patients with Spherblock ball attachment (58 patients), Dolder bar with cantilever (36 patients), and Locator attachment (9 patients). Marginal bone‐loss around implants, prosthetic complications, soft tissue status of the implants (gingival index, plaque index, pocket depth, and bleeding on probing) were used to compare studied groups. Visual Analogue Scale (VAS) criteria was used to assay patient's satisfaction. One‐way ANOVA, Scheffe, Kruskal–Wallis, Mann–Whitney, and Fisher's exact tests, were used for the data analysis (α = 0.05). Results: One hundred and three patients (46 male, 57 female, mean age 64.7 ± 8.6) with 206 implants (Strauman) were studied. The implant survival rate was 100% with mean bone loss of 0.22 mm around implants in 5 years. Prosthetic complications including attachment wear and denture fracture occurred more often with ball attachments. The number of attachment replacement, and post insertion appointments were significantly less in patients with bar attachments (p < 0.05). Pocket depth and gingival index were less in the ball attachment (p < 0.05). Conclusion: Mandibular overdenture supported by two implants can be considered a successful treatment in edentulous patients. The frequency of prosthetic complication is higher in unsplinted than splinted superstructures. [ABSTRACT FROM AUTHOR]

Today, two different types of CAD-CAM fabrication methods for complete denture bases are available besides the conventional protocols: a subtractive milling process from a prepolymerized block of polymethylmethacrylate and an additive manufacturing process that built the denture base using a light-cured liquid in a VAT-polymerization process. The aim of this study was to evaluate and to compare the accuracy and precision of denture prosthetic bases made with subtractive and additive manufacturing technologies and to compare them with a denture base with the conventional method in muffle. From the results obtained, 3D printing dentures show a statistically significant higher accuracy than milled prosthetic bases. Milled prosthetic bases have similar accuracy than conventional fabricated dentures.

(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. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to assess the occlusal contact area (OCA), occlusal contact number (OCN), bite force, and artificial tooth wear in complete dentures with lingualized and bilateral balanced occlusion., Methods: Edentulous participants who fulfilled the inclusion criteria were divided into the three groups as follows: group I, dentures with lingualized occlusion using interpenetrating polymer network artificial teeth; group II, dentures with lingualized occlusion using double cross-linked artificial teeth; and group III, dentures with bilateral balanced occlusion using anatomical micro-hybrid resin teeth. The silicone techniques were used to assess the OCA and OCN of the mandibular dentures and the Dental Prescale II was used to evaluate the bite force at the 2-week, 3-month, and 12-month follow-up visits. Occlusal contact analyzer software was used to assess the maxillary and mandibular posterior tooth wear at the 12-month follow-up visit. All data was analyzed using the SPSS software., Results: The OCA of group III was significantly higher than that of groups I and II at the 2-week follow-up visit, whereas group I was considerably higher than groups II and III at the 3-month and 12-month follow-up visits. The OCN of the three groups exhibited significant differences at all three follow-up visits. Groups I and II had significantly lower bite force than Group III at the three follow-up visits. At the 12-month follow-up visit, groups I and II had significantly higher wear than Group III., Conclusions: As the duration of use increases, the occlusal contact area of complete dentures increases, regardless of the occlusal schemes. The bite force of lingualized occlusion is typically lower than that of bilateral balanced occlusion. The wear locations of artificial teeth differ between the two types of occlusal schemes. (Retrospectively registered: The Chinese Clinical Trial Registry, No. ChiCTR2300073420(11/07/2023))., Competing Interests: Declarations Ethics approval and consent to participate The study was carried out in compliance with the Helsinki Declaration, approved by the Medical Ethics Committee of Dalian Stomatological Hospital (Ethics Review Batch No. DLKQLL2019015, 28/11/2019) and retrospectively registered in the Chinese Clinical Trial Registry (No. ChiCTR2300073420, 11/07/2023). Informed consent was obtained from all subjects involved in the study.This study adheres to CONSORT guidelines. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Objectives: This crossover randomized controlled clinical trial (RCT) aimed to evaluate the clinical applicability of three-dimensional printed dentures (CAD-3DPs) by comparing two fabricated complete dentures, CAD-3DPs and conventional complete dentures (CCDs), and assess the non-inferiority of CAD-3DPs. The hypothesis was that CAD-3DPs would be inferior to CCDs in terms of the oral health-related quality of life (OHRQoL) and patient satisfaction., Methods: This single-blind RCT was conducted at two university hospitals. The participants included adult patients with edentulous maxillary and mandibular arches, who had existing complete dentures and were willing to use new complete dentures. Eighteen participants were assigned to two groups: CCD-CAD-3DP and CAD-3DP-CCD, based on the order of denture delivery. Both sets of maxillary and mandibular CCDs and CAD-3DPs were delivered to all the participants. The OHRQoL using Oral Health Impact Profile for Edentulous Patients (OHIP-EDENT-J) was considered the primary outcome. General satisfaction using a 100-mm visual analog scale was also evaluated as a suboutcome., Results: Based on the non-inferior test on the total score of the OHIP-EDENT and each score of the seven conceptual subdomains, the lower limit of the 95 % confidence interval was < 2.65 in seven domains. Therefore, CAD-3DP was judged to be non-inferior to CCD. Patient satisfaction was not significantly different between the CCD and CAD-3DP groups (p > 0.05)., Conclusions: This RCT revealed that CAD-3DP is comparable to CCD based on the OHIP-JDENT scores and patient satisfaction., Clinical Significance: CAD-3DP is clinically applicable and comparable to CCD in terms of patient-reported outcomes., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Maiko Iwaki reports financial support was provided by Japanese Dental Science Federation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: The literature is unclear about how the different attachment systems for overdentures impact the maximum bite force, the masticatory efficiency and how this impact in the oral health self-perception in patients., Objective: To evaluate the effect of two attachment systems (O-ring and Locator) for mandibular overdenture using single implant on quality of life, maximum bite force (BF) and masticatory efficiency (ME)., Methods: Twenty-eight completely edentulous denture wearers with a mandibular symphysis implant were randomly selected and allocated into two groups in a crossover study, considering O-ring and Locator attachment types. The quality of life and self-perception of oral health were assessed using the Oral Health Impact Profile (OHIP-Edent) and Geriatric Index of Determination of Oral Health (GOHAI) questionnaires, respectively. BF was measured using a gnathodynamometer and ME by chewing silicone cubes and almonds in different numbers of cycles., Results: There was no difference between the attachment systems about self-perceived oral health and impact on quality of life (p > .05). The O-ring-type system obtained a significantly higher BF than the locator-type system (p = .04). Regardless of the food chewed, no statistically significant difference was observed with the type of attachment (p > .05). The ME was directly proportional to the masticatory cycles only for almonds (p < .01)., Conclusions: Locator and O-ring inserts had a similar impact on patients' quality of life, self-perception of oral health and ME. Additionally, the O-ring system exhibited superior properties in the BF., (© 2024 John Wiley & Sons Ltd.)

Objectives: The polymer polyetheretherketone (PEEK) is gradually being used in dental restorations because of its excellent mechanical properties, chemical resistance, fatigue resistance, thermal stability, radiation translucency and good biocompatibility. To process PEEK dentures with lower surface roughness as quickly as possible, the non-dominated sorting genetic algorithm-II (NSGA-II) integrated genetic algorithm back propagation (GABP) neural network was proposed, which can adjust the combination of process parameters for milling PEEK dentures., Methods: The PEEK machining was conducted using a four-axis dental milling machine at different process parameters. The surface roughness of PEEK dentures was characterized using surface roughness profiler and scanning electron microscopy (SEM). The optimum machining performance of milling PEEK dentures was investigated using a multi-objective optimization model named as NSGA-II integrated GABP neural network algorithm. The surface roughness (Ra) and material removal rate (MRR) were used as optimization objectives., Results: The multi-objective optimization model effectively improved surface roughness and machining efficiency for milling PEEK dentures. The validation experiments showed that the surface roughness of all PEEK dentures was less than 0.2μm, which was within the range of surface roughness set in this paper. The GABP surface roughness prediction model had an average error of 6 %. For the same surface roughness value, the optimized milling parameters all had a greater material removal rate., Significance: The research results can improve current PEEK denture CAD/CAM technology by providing appropriate milling parameters using NSGA-II integrated GABP algorithm., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Statement of Problem: The absence of a tooth in the esthetic zone can cause emotional and social distress. The use of minimally invasive and visually pleasing lithium disilicate resin-bonded fixed dental prostheses (RBFDPs) may be a suitable option for replacing a missing maxillary incisor. However, the available literature on lithium disilicate cantilever RBFDPs is limited., Purpose: This retrospective multicenter study assessed the survival and success rates of lithium disilicate anterior cantilever RBFDPs with an average follow-up period of 3 years up to 9 years., Material and Methods: RBFDPs delivered by 3 operators were clinically assessed for survival using a modified United States Public Health Service criteria list. The incidence density was determined for each criterion and operator. The standard error and 95% confidence interval were calculated for each incidence density difference (α=.05 for all analyses)., Results: A total of 108 RBFDPs were evaluated after a mean period of 32.45 months, ranging from 14 days to 111 months. None of the restorations exhibited failure, carious lesions, or fractures during the follow-up period. The primary reasons for reduced success rates were inflammation of the surrounding soft tissues and discoloration, with incidence densities of 0.074 and 0.057 per year, respectively. Significant differences were observed among RBFDPs from different operators for criteria that included adaptation, color match, marginal adaptation, polishability, surface staining, gingival health, and antagonist wear., Conclusions: Cantilever lithium disilicate RBFDPs appear to be suitable for short-term restoration. RBFDPs exhibited visible changes after short-term follow-up. However, these changes did not result in failure., (Copyright © 2024 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Several impression techniques and theories have been developed for implant-retained overdentures, each with its own set of advantages and limitations. This study aimed to assess the chewing efficiency of mandibular implant-retained overdentures fabricated using three distinct impression techniques (mucofunctional, selective, and minimal pressure impression techniques). Twenty-six patients with complete edentulism free from any oral or systemic disease were selected to participate in the study. Three complete mandibular implant-retained overdentures were constructed for each patient, and grouped into three groups according to the impression technique employed in overdenture construction; Group A: Patients were treated by mandibular implant-retained overdenture fabricated using mucofunctional impression technique; Group B: Patients were treated by mandibular implant-retained overdenture fabricated using selective pressure impression technique; Group C: Patients were treated by mandibular implant-retained overdenture fabricated using minimal pressure impression technique. Chewing efficiency was evaluated for each patient with the implant-retained mandibular overdenture after three months of prosthesis insertion as an adaptation period. The data were collected, tabulated, and statistically analyzed. Results indicated that mandibular implant-retained overdentures made using the mucofunctional impression technique showed higher mean values of chewing efficiency parameters than mandibular overdentures made using selective and minimal pressure impression techniques. Within the limitations of this study, it can be concluded that the mucofunctional impression technique may be effective in improving the chewing efficiency of mandibular implant-retained overdentures more than minimal or selective pressure impression techniques.

Objectives: To evaluate clasp-retained removable partial dentures (C-RPDs) with a metal framework for survival, maintenance requirements, and biologic implications., Method and Materials: C-RPDs were retrospectively analyzed based on patient records. Treatment failure was defined as fracture of a framework component (metal base or connector) or loss of an abutment tooth. Other outcome variables included factors that might conceivably impact C-RPD survival (maxilla vs mandible, Kennedy classes, opposing dentitions, treatment by students vs certified dental practitioners), mobility and caries of abutment teeth (in relation to clasp designs), and maintenance requirements (relining, clasp or resin fractures). Differences were evaluated by appropriate statistical tests at the P ≤ .05 level., Results: A total of 612 patients (339 men, 273 women) 60.0 ± 11.5 years old at delivery were included, covering 842 C-RPDs and a mean observation period of 42.1 ± 33.2 months. Kaplan-Meier C-RPD survival was 76.2% after 5 years and 49.5% after 10 years. Biologic complications (ie, loss of abutment teeth) accounted for the vast majority (95.6%) of C-RPD failures, and Kaplan-Meier C-RPD survival was significantly better in the mandible (P = .015). Some clasp designs contributed significantly to caries and removal of abutment teeth (both P .05). No other significant differences were noted., Conclusion: Tooth loss both emerges as the main cause of C-RPD failure and might be amenable to careful selection of clasp designs. Overall, better C-RPD survival should be expected in the mandible. A noncontributory role of Kennedy classes and opposing dentitions is tentatively suggested based on numerically heterogenous subgroups.

This clinical report summarizes a workflow that introduces two approaches for fabricating a metal framework removable partial denture for a marginal mandibulectomy patient. First, the pre-existing denture was adjusted according to the piezographic technique to determine the optimal configuration for adhering to the available denture space. Second, computer-aided design-computer-aided manufacturing (CAD-CAM) technology was used to fabricate a new removable partial denture by digitally scanning the oral condition and the well-adjusted denture and then using the obtained data to design and fabricate the new denture. These two approaches can help to reduce chair time not only for maxillofacial prosthetic treatment but also for other denture cases.

Aim: The aim of the present in vitro study was to investigate the effects of different sintering procedures on the fit, color parameters, and fracture load of monolithic fixed partial prostheses (FPPs)., Materials and Methods: A metal master model was scanned and FPPs were designed. Groups were created by fabricating FPPs using four different sintering procedures (n &#61; 10): Prettau-Standard (PST); Prettau-Slow (PSL); Ice-Speed (ISP); Ice-Standard (IST). PST-PSL (Group P; N &#61; 20) and ISP-IST (Group I; N &#61; 20) were colored with different coloring liquids. The marginal and internal fit were measured using the silicone replica method. CIELAB values of the samples were measured using a spectrophotometer. Then, for each sample, the die was obtained from polymethyl methacrylate. The specimens were cemented into dies and tested in a universal testing machine for fracture load. One-way ANOVA was performed to assess the effect of the sintering procedure on the marginal and internal fit; fracture load; and ∆E00, ∆L', ∆C', and ∆H' values of the FPPs., Results: The PSL and PST groups showed significantly smaller internal and marginal fit values compared with the ISP group. Additionally, the internal fit values of the IST group were significantly higher than those of Group P. Sintering time reduction led to a decrease in ∆E00 values. Fracture load values were not statistically significantly affected by the different sintering procedures for both brands., Conclusion: Different sintering procedures did not have a clinically significant effect on fit and fracture load. Different sintering procedures were found to have an impact on the color change of monolithic zirconia restorations.

The provision of removable partial dentures (RPDs) is an important skill for practitioners and it can often be challenging to make a successful prosthesis which the patient finds satisfactory. This three-part series has been designed to provide an overview of the clinical management of patients requiring RPDs. This first part provides a refresher of the aspects of the history and examination that are relevant to RPDs. We describe some key principles that are relevant to challenging denture cases. This will help the reader begin the treatment planning process and understand some of the factors which influence the prognosis of dentures., (© 2024. The Author(s), under exclusive licence to the British Dental Association.)

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., (© 2024. The Author(s), under exclusive licence to The Society of The Nippon Dental University.)

This clinical report describes the prosthodontic management of a 5-year-old boy with ectodermal dysplasia who had been followed for 31 years. During the first 15 years, several interim removable overdentures were fabricated and modified according to his skeletal growth. At age 20, after the completion of jaw development, 4 endosseous dental implants were inserted in the mandible with a nerve repositioning procedure. After a 6-month healing period, maxillary and mandibular double crown removable partial dentures (RPDs) using a gold electroforming system were delivered. In the 16 years since delivery, the implants and abutment teeth have shown no pathologic signs. The double crown RPDs supported by implants and natural teeth were found to be an effective, long-term stable treatment option for this patient with hypodontia. The authors are unaware of a longer follow-up period of dental rehabilitation in a patient with ectodermal dysplasia providing satisfactory functional and esthetic results., (Copyright © 2024 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objectives: Conventionally and digitally manufactured removable complete dentures with different dentition forms were examined for manufacturing accuracy (trueness, precision), fracture forces under torsional loading and subsequent repairability., Methods: A total of 90 mandibular prostheses were manufactured. Ten were made using the injection molding technique and finished with prefabricated teeth. 40 bases each, were manufactured subtractively and additively. Digitally the prosthesis' dental arch was divided either into two quadrants or three sextants, or kept as full arch. Afterwards, ten additive and subtractive bases were finished with prefabricated teeth and ten of each with milled quadrants, sextants and full arches. After manufacturing, all specimens were rescanned for accuracy comparisons using the Root Mean Square (RMS). Lastly, all specimens were tested to failure under torsional loading., Results: Conventionally manufactured dentures showed the greatest deviation in accuracy. The type of base manufacturing did not determine the fracture resistance of the prostheses. The dentition form had a significant influence. While prefabricated teeth (86.01 ± 19.76 N) and quadrants (77.89 ± 9.58 N) showed a low fracture resistance, sextants (139.12 ± 21.41 N) and full arches (141.05 ± 17.14 N) achieved the highest fracture forces. Subtractive bases with prefabricated teeth or quadrants were assessed to be repairable, digital dentures with full arch were assessed as not repairable., Significance: The presented testing set-up is suitable to determine the fracture behavior of dentures rather than of standards. With the possibility of digital design and individual manufacturing, dentures' mechanical stability can be significantly increased, especially with suitable dentition forms., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: To explore the clinical application of one-piece polyetheretherketone (PEEK) removable partial dentures (RPDs) fabricated using a novel digital workflow and to evaluate their weights and fits in vivo and patient satisfaction., Materials and Methods: Fifteen cases with posterior partially edentulous situations were selected, and each patient received two types of RPDs, including a novel digital workflow (test group) and a conventional workflow (control group). For the test group, one-piece RPDs were designed through three-dimensional (3D) methods by scanning stone casts and fabricated by milling PEEK discs. Each RPD was weighed. The gaps between the oral tissue and RPDs in each group were duplicated using a polyvinylsiloxane (PVS) replica and measured by 3D analysis. A visual analog scale (VAS) was used to evaluate the patient's satisfaction. Paired t-tests were used to compare the differences in the weight, the gaps of each RPD, and VAS values between the two groups. One-way analysis of variance tests was used to compare the differences in the gap among different components in each group., Results: The RPD in the test group weighed less than that in the control group (p < 0.01). No statistically significant differences in the gaps of denture bases and rests (p > 0.05) were found between the two groups, but the gaps of major connectors in the test group were significantly smaller than in the control group (p < 0.05). The VAS scores for comfortableness and masticatory efficiency were not significantly different between the two groups (p > 0.05) but the scores for the aesthetic appearance of the clasps in the test group were significantly higher than that in the control group (p < 0.05)., Conclusions: One-piece PEEK RPDs manufactured using a novel digital workflow weighed less than conventional RPDs and exhibited a clinically acceptable internal fit. Although the aesthetic appearance of the PEEK clasps was superior to the control, there is still room for improvement., (© 2024 by the American College of Prosthodontists.)

Statement of Problem: The accuracy and optimal dimensions of computer numerical control (CNC)-milled polyetheretherketone (PEEK) removable partial denture (RPD) clasps are unclear., Purpose: The purpose of this in vitro study was to investigate the trueness and precision of CNC-milled PEEK clasps with different thicknesses and lengths., Material and Methods: Ladder-shaped specimens of 2 thicknesses with 5 lengths of clasps were designed and milled with PEEK and commercially pure titanium (CP Ti) (n=6). All milled specimens were scanned and superimposed onto the design data. Three-dimensional and 2-dimensional deviation analyses were carried out to evaluate the trueness of milled PEEK clasps. The scanning data of each group were superimposed pairwise, and the 3-dimensional deviations were analyzed to evaluate the precision. Nonparametric tests, ANOVA, the Pearson correlation, and univariate linear regression were used for statistical analysis (α=.05)., Results: The deviation of trueness of the PEEK clasps (0.047 to 0.164 mm) was higher than that of the CP Ti clasps (0.037 to 0.060 mm) (P<.001). Increasing the length of the clasps increased the deviations (P<.001). Deviation in the 2 thicknesses was not significantly different (P=.210). The correlation coefficients of 1.0-mm-thick and 1.5-mm-thick PEEK and CP Ti clasps were 0.843, 0.794, 0.638, and 0.405. The positive correlation coefficients of PEEK were higher than those of CP Ti and those of 1.0-mm-thick clasps was higher than those of 1.5-mm-thick clasps. The deviations were evenly distributed in the 9-mm length of the clasp for CP Ti and in the 6-mm length of the clasp for PEEK. Beyond these lengths, deviations increased with increased length. The increasing amplitude of CP Ti was smaller than that of the PEEK group, and that of the 1.5-mm-thick clasp was smaller than that of the1.0-mm-thick clasp. The measured range of precision of PEEK clasps was 0.079 to 0.152 mm, while that of CP Ti clasps was 0.036 to 0.096 mm. CP Ti clasps tended to have better precision than PEEK clasps, except for the 1.0-mm-thick clasps with a length greater than 9 mm and the 1.5-mm-thick clasp with a 12-mm length. The correlation of the clasp length with precision showed that the lengths of 1.0-mm-thick clasps strongly influenced precision (PEEK, P=.020; CP Ti, P<.001); this correlation decreased sharply when the thickness of clasps was 1.5 mm (PEEK, P=.199; CP Ti, P=.107)., Conclusions: Greater elasticity increased the deviations of milled clasps. The increased thickness helped the clasp remain stable during the milling process. The 1.5-mm-thick PEEK clasps in the 3-mm and 6-mm lengths were the optimal design tested., (Copyright © 2022 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Completely veneered zirconia ceramic (ZC) fixed partial dentures (FPDs) have been reported to have a higher incidence of ceramic chipping than the standard metal-ceramic FPDs. However, data from comparative long-term studies are sparse., Purpose: The purpose of this retrospective study was to compare the long-term survival, chipping-free survival, and success of ceramic-veneered high noble metal alloy (HN), base metal alloy (cobalt-chromium alloy) (CC), and ZC FPDs and to isolate risk factors for the incidence of failure, veneer chipping, and overall complications., Material and Methods: Data from 289 study participants (58.7% women; mean age, 57.97 ±11.51 years) provided with a total of 400 FPDs comprising 197 (49.3%) HN FPDs, 121 (30.3%) CC FPDs, and 82 (20.5%) ZC FPDs fabricated from presintered 3 mol% yttria-stabilized zirconia (mean time of service, 6.85 ±3.25 years) were evaluated. Of these, 278 (69.5%) FPDs were provided by dentists and 122 (30.5%) by dental students. Five- and 10-year survival, chipping-free survival, and success rates were calculated using the Kaplan-Meier method and compared with the log-rank test. Risk factors were assessed using Cox regression analysis. The study was exploratory, so all P values were considered exploratory and descriptive., Results: The 5- and 10-year survival rates were 94.7% and 77.8% for HN, 93.7% and 81.2% for CC, and 92.9% and 53.3% for ZC FPDs, respectively, indicating no clear difference in survival among the framework materials. The 5- and 10-year chipping-free rates were 94.1% and 82.8% for HN, 96.1% and 78.9% for CC, and 82.6% and 62.2% for ZC FPDs, respectively, indicating a difference between HN and ZC, and CC and ZC restorations. The 5- and 10-year success rates were 83.7% and 55.3% for HN, 86.5% and 51.4% for CC, and 68.9% and 30.2% for ZC FPDs, respectively, indicating a difference between HN and ZC, and CC and ZC restorations. The Cox regression model indicated framework material as an influencing risk factor for success, and this influence persisted when chipping was investigated. Compared with zirconia, the use of a metal alloy reduced the risk of chipping or the occurrence of complications by up to one-third., Conclusions: All FPDs showed high 5-year survival rates and acceptable 10-year survival rates with no strong differences among the materials. Higher success and chipping-free rates were observed for both HN and CC restorations compared with ZC restorations. Metal frameworks had a lower risk for complications or veneer chipping than zirconia frameworks., (Copyright © 2022 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to evaluate the effect of the All-on-4 design and 4 alternative implant-supported fixed prosthesis designs on stress distribution in implants, peri-implant bone, and prosthetic framework in the edentulous mandible under different loading conditions using three-dimensional finite element analysis (3D-FEA).Five different experimental finite element models (Model A (unsplinted 6), Model B (splinted 6), Model C (All-on-4), Model D (axial; 2 anterior, 2 posterior), and Model E (4 interforaminal)) were created. Three different loading conditions were applied (canine loading, unilateral I-loading, and unilateral II-loading). The highest minimum (Pmin) and the maximum (Pmax) principal stress values were acquired for cortical and trabecular bones; the highest von Mises (mvM) stress values were obtained for implants and metal frameworks. Model B and Model D showed the most favorable stress distribution. The All-on-4 design (Model C) also showed acceptable stress values close to those of Model B and Model D in the cortical and trabecular bones. In accordance with the stress values in the bone structure, the lowest stress values were measured in the implants and Co-Cr framework in Model B and Model D. The highest stress values in all structures were measured for unilateral loading- II, while the lowest values were found for canine loading. It was concluded that Model B and Model D experimental models showed better biomechanical performance in all structures. Furthermore, the use of a splinted framework, avoiding cantilevers, results in lower stress transmission. On the other hand, canine loading and unilateral loading-I exhibited the best loading conditions., (© 2024. The Author(s).)

This study evaluated fracture resistance of monolithic fixed dental prostheses (FDPs) fabricated using different placement strategies of various connector designs in multilayered zirconia disc. Monolithic FDPs were placed in translucent and dentin layers of multilayered zirconia disc and fabricated with V-shaped and U-shaped connector designs gained by sharp and blunt millings. The FDPs were cemented on abutment models made of polymer material, underwent thermal cycles, and loaded to fracture using the universal testing machine. Fracture loads and modes were analyzed using two-way ANOVA, Tukey's post hoc test, and Fisher exact test (p≤0.05). The chosen placement strategy and connector designs gained by different milling procedures in computer-aided design/computer-aided manufacturing technology affect fracture resistance of monolithic FDPs made of multilayered zirconia materials. Placing the connector in translucent layer rather than dentin layer of multilayered zirconia disc and using sharp milling significantly reduces fracture resistance of monolithic multilayered zirconia FDPs.

This study aims to assess the dimensional accuracy of complete denture bases fabricated from different CAD/CAM technologies and a conventional method, including milling (CNC), PolyJet (PJ), laser sintering (SLS), digital light processing (DLP), and injection molding (IM). It also examines the influence of the removal of technology-specific connectors or support structures when present. Denture base surfaces were digitized using a laboratory scanner, and virtual measurement points were calculated with tetrahedral reference geometries. Defined distances were measured in all spatial directions and compared to design data (p<0.05), revealing significant differences in sagittal (p=0.004), transversal (p<0.001), and vertical (p<0.001) dimensions. Connector removal had no significant impact for CNC but significantly affected DLP. All technologies yielded clinically acceptable results, with CNC milling demonstrating the best overall outcome.

Background: Failure to restore missing teeth in time can easily lead to the mesial tilting of the distal abutment teeth. However, a fixed partial denture (FPD) can improve stress conduction and distribution and prevent periodontal injuries. In these more complex cases, it is necessary to consider various factors comprehensively to improve conventional treatment planning and achieve better results., Methods: We selected a patient with a missing first molar and a mesial inclination of the second molar, leaving inadequate space or bone mass for implant denture restoration, necessitating an FPD for restoration. Three-dimensional finite element analysis (3D-FEA) combined with photoelastic analysis were used to explore how the inclination angle (0 ‒ 30°) and different dental restoration materials (zirconia, lithium disilicate, polymer-infiltrated ceramic network, and resin composite) affect the biomechanical behaviour of FPD‒abutments‒periodontal tissue complex., Results: The stress was easily concentrated in the FPD connectors, enamel shoulder collar, periapical area, and root bifurcation. The stress on FPD and the periodontal ligament (PDL) of the second premolar increased with an increase in the elastic modulus of FPD, with an opposite trend in the abutments, the alveolar bone, and the PDL of the second molar. The stress on the FPD and alveolar bone increased with increased inclination angle of the distal abutment. The stress on two abutments and their PDL were positively correlated with the inclination angle in two stages; however, when the inclination angle > 12°, the second premolar and its PDL showed a negative correlation., Conclusions: FPDs can be used for restoration within 24° of distal abutment inclination, but protecting the abutments (< 12° especially) and the periodontal tissue (> 12° especially) must be taken seriously. For this purpose, an FPD material with higher strength is recommended., (© 2024. The Author(s).)

Purpose: To review the literature on CAD/CAM removable complete and partial dentures regarding patient- and clinician-reported outcomes., Materials and Methods: We performed an electronic search of the Cochrane Central Register of controlled trials (CENTRAL), MEDLINE (Ovid), EMBASE, Scopus, and Web of Science databases (last update: March 2023). All clinical trials or observational studies investigating CAD/ CAM removable dentures (conventional or implant-retained) were included., Results: The search yielded 4,035 records and led to 58 included studies. Results suggest that CAD/CAM complete and partial dentures, when compared to the conventional ones, can save time and resources while being rated either noninferior or superior by patients and clinicians in most studies. However, consensus on which workflow offers fewer adjustments and postoperative sessions is still pending., Conclusions: The literature suggests that CAD/CAM complete and partial dentures can combine substantial time and cost savings, with patient and clinician experiences at least comparable to conventional prostheses. Given the low evidence level of existing studies, future well-designed randomized trials with large sample sizes are required to confirm those advantages.

Background: There is a lack of studies comparing the dimensional accuracy and color stability of denture base resins made using computer-aided design and computer-aided manufacturing (CAD-CAM) milling, 3-dimensional (3D) printing, and conventional denture processing techniques. This makes it challenging to determine the best method to fabricate complete dentures. The objective of this in vitro investigation was to assess and contrast the color stability and dimensional accuracy of denture base resins that were 3D printed and CAD-CAM milled, both before and after aging by thermocycling using digital surface matching technology and a benchtop laser scanner without using a spray, to optimize adaptation of the denture base and cast to minimize any imperfections and to evaluate the impact of the denture cleansing solution on the stability of color., Methods: Evaluation of the dimensional accuracy (n = 27) was completed on a sectional maxillary stone cast using a digital 3D-surface matching software before and after 5000 thermocycles. A spectrophotometer was used to measure the color change (△E00) of all disc specimens (N = 54) before and after 500 thermocycles and immersion in denture cleansing solution for 30 cycles (3 min each) daily for 6 days. The Kruskal Wallis test, Dunn's post hoc test, Tukey's test with Bonferroni adjustment, one sample t test and independent t test were used to statistically analyze the data (α < 0.05)., Results: Thermocycling decreased the dimensional accuracy of the heat polymerized group at all 5 locations and the 3D-printed group at locations 1, 3 and 5 (P > .05), while it had no significant difference on the CAD-CAM milled group at all locations (P < .05). The color change (△E 00 ) was lowest in the CAD-CAM milled group, moderate in the heat-polymerized group and highest in the 3D-printed group. After immersion in denture cleanser, the color change (△E 00 ) was significantly higher in the 3 groups compared with after thermocycling (P > .001)., Conclusions: CAD-CAM milled resins had the highest dimensional accuracy and the best color stability, conventional heat polymerized acrylic resins showed moderate change in dimensional accuracy and color stability, while the 3D- printed resin had the lowest dimensional accuracy and color stability after aging by thermocycling., (© 2024. The Author(s).)

Background: Decreased salivary flow can make the patients uncomfortable with their complete dentures and affects the retention of the dentures. Milling and 3D printing have become an alternative to conventional denture construction techniques. The goal of this study was to evaluate the effect of conventional and digital techniques of the complete denture construction on the denture surface wettability with distilled water and saliva substitute before and after thermocycling., Methods: A total of 30 specimens were utilized in the present study. Specimens were divided according to the construction techniques into 3 groups (n = 10 each). Group I: Heat-polymerized polymethylmethacrylate (PMMA) group, group II: Milled group, and group III: 3-dimensional (3D)-printed group. All the specimens were subjected to 2000 cycles of thermal aging in a thermocycler. The wettability of all specimens to water and saliva substitute was measured via a contact angle goniometer (Olympus TGHM, Rame-hart Inc, USA) before and after thermocycling. Descriptive statistical analysis, plots, and the Shapiro-Wilk test were used to verify normality for each variable. One-way ANOVA was used to compare the 3 study groups, while paired samples t-test was used to compare the differences within each group (P < .05)., Results: The smallest contact angle of drop of water to the denture base specimens before and after thermocycling were recorded in the milled group (53.0 ± 4.77 and 50.27 ± 2.30, respectively), followed by the heat polymerized PMMA group (85.65 ± 4.71 and 65.06 ± 2.27, respectively), and the 3D-printed group (91.34 ± 6.74 and 90.86 ± 8.57, respectively). While the smallest contact angle of drop of saliva substitute to denture base specimens was recorded in the milled group (56.82 ± 2.29 and 34.85 ± 7.51, respectively), followed by the 3D-printed group (72.87 ± 4.83 and 58.14 ± 9.58, respectively) and the heat polymerized PMMA group (83.62 ± 4.12 and 67.82 ± 4.93, respectively). There was statistically significant difference between the groups (P < .05). A significant decline in the average contact angle of drop of saliva has been reported in all groups after thermocycling. The contact angle values differed significantly between saliva substitute and distilled water in both 3D-printed and milled groups after thermocycling (P < .001)., Conclusions: The milled denture base material presented the best wettability to water and saliva substitute than the 3D-printed and the heat-polymerized PMMA materials. Saliva substitutes improve the wetting ability of denture base materials manufactured by CAD/CAM compared with water., (© 2024. The Author(s).)

Introduction: The primary challenge associated with implant overdentures lies in the occurrence of denture fractures around the attachments. Hence, it is recommended to enhance flexural strength through reinforcement frameworks. This study aimed to assess and compare the prosthetic maintenance of mandibular implant overdentures reinforced with Co-Cr and PEKK frameworks., Methods: Twenty-four participants with completely edentulous ridges were selected, and two implants were placed at the mandibular canine areas. After osseointegration period, ball attachments were installed. Participants were randomly assigned into two groups: Group I received a mandibular implant overdenture reinforced with a Co-Cr framework, while Group II received a mandibular implant overdenture reinforced with a PEKK framework. Prosthetic maintenance evaluations were conducted in both groups twelve months post-denture insertion. Categorical data were analyzed, and results were presented as frequency and percentage values., Results: Group II exhibited a significantly higher percentage of cases with screw looseness, denture relining, and tooth separation compared to Group I. Although Group II cases showed a non-significant increase in the percentage of insert wear and retention loss., Conclusion: Within the limitations of this study, the findings suggest that Co-Cr, in contrast to PEKK frameworks, offers a more reliable reinforcement of the implant-retained overdentures., (Copyright© 2024 Dennis Barber Ltd.)

Objective: The aim of this study was to assess the feasibility of digitally scanning dentures and 3D printing replica dentures for care home residents. The study also investigated whether the process and replacement denture was acceptable to the resident., Background: Denture loss is a significant issue for people living in care homes and impacts on nutrition, quality of life and dignity. Denture loss is underreported, and care home residents have barriers to accessing dental care. The conventional process for remaking a denture can often take approximately 2 months with multiple clinical stages, often not feasible in adults with frailty and cognitive impairment. Scanning and 3D (3 dimensional) printing are increasingly used in dentistry, this rapidly evolving technology may provide an innovative solution to denture loss., Materials and Methods: A digital workflow was established using a handheld scanner and 3D printing technology. Care home residents wearing functional acrylic dentures were recruited. Dentures were scanned within the care home, and the scan was sent to a dental laboratory for 3D printing. The dentures were fitted at a subsequent visit, and semi-structured interviews were undertaken with the resident. Using thematic analysis, the feasibility of this pathway was assessed, and the use of digital scanning technology was explored., Results: Eight residents successfully had dentures scanned and replicated to a satisfactory standard. It took, on average, 10 minutes to scan a denture and 20 minutes to print the denture. All replica dentures were satisfactory to the resident. Qualitative data from semi-structured interviews showed that study participants were satisfied with denture replacements and the process. The 3 main themes that emerged were: the significance of dentures to the individual, satisfaction with the scanning process and general low self-esteem and fatigue., Conclusions: This study has established a workflow for digitally storing dentures and replicating them satisfactorily. In the context of a care home setting, a scan of a denture can be used to provide a replacement denture if lost or broken. A large-scale study could follow now that the feasibility of this pathway has been demonstrated., (© 2023 Gerodontology Association and John Wiley & Sons Ltd.)

Mandibular flexure is a phenomenon generated by the action of the muscles of mastication and other muscles in the head and neck region which can lead to prosthetic and biological complications such as pain, material fracture, and bone loss around dental implants. To avoid such complications, dividing the mandibular prostheses into 3 short-span prostheses or sectioning at the midline has been suggested. This clinical report presents the management of an edentulous patient with clinically detectable mandibular flexure treated with a 1-piece metal-free complete arch implant-supported prosthesis., (Copyright © 2023 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The impact of thermal cycling on the flexure strength of contemporary denture base materials remains inadequately understood despite its crucial role in determining the long-term performance of complete dentures., Purpose: The purpose of this in vitro study was to evaluate the flexural strength of different CAD-CAM denture base materials and the effects of thermal cycling., Material and Methods: A total of 120 rectangular specimens were fabricated from 6 denture base materials according to the International Organization for Standardization (ISO) 20795-1:2013 standard: a heat-compressed PMMA ([Lucitone 199 [C-L199]), 2 brands of milled material (Ivotion Base [M-IB] and Lucitone Digital Fit [M-LDF]), and 3 types of 3- dimensionally (3D) printed material (Lucitone Digital Print [P-LDP], Flexcera Base [P-FB], and FotoDent Dentures [P-FD]). Specimens were divided into 2 subgroups of 10; half underwent thermocycling, half did not. Thermally cycled specimens were immersed in distilled water at 37 °C for 2 days, followed by 5000 thermal cycles at 5 and 55 ºC, with a dwell time of 30 seconds. They were then subjected to a 3-point flexural strength test. Two-way ANOVA, followed by post hoc Tukey multiple comparison tests were used to assess the effect of material type and the thermal cycling process on the flexural strength of denture base materials (α=.05)., Results: All materials met the ISO standard of 65 MPa flexural strength, except for thermal cycled P-FB. A significant difference (P<.05) in flexure strength value was found among various denture base materials without thermal cycling (M-LDF>M-IB≈P-FD≈P-LDP>C-L199≈ P-FB) and with thermal cycling (M-LDF> M-IB≈P-FD>P-LDP≈C-L199>P-FB). The flexural strength of tested materials was reduced significantly (P<.05) with thermal cycling., Conclusions: Three-dimensionally printed denture base materials have a flexural strength value similar to or less than that of milled denture base materials. Thermal cycling impacts the flexural strength of denture base materials., (Copyright © 2024 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objectives: to assess the survival rates of removable partial dentures (RPDs) and identify factors impacting their longevity., Methods: electronic health records were retrieved of patients aged ≥18 who received RPDs between 2010 - 2021 with a follow-up of ≥ three months. Data extracted included demographics, medical history, dental charting, periodontal screening and recording scores, prostheses details and related interventions, including new dentures/denture remakes, and maintenance. Multivariate Mixed-Effect Cox regression was performed to identify potential RPD survival risk factors. Reduced model selection was reached using a backward step-down by comparing the performance of these multivariable models using the ANOVA test., Results: 1893 RPDs from 1246 patients were included, with a median follow-up of 21.8 months (range from 3 to 131.3 months). Three hundred and twelve patients received a maxillary RPD, 460 received a mandibular RPD, and the remaining 474 patients received both maxillary and mandibular RPDs. Metal-based RPDs had a median survival of 73 months (95%CI: 70 - 82) versus 45 months (95% CI: 37-67) for acrylic ones. Multivariable mixed effects Cox model showed that the lifespans of RPDs were longer amongst patients receiving more maintenance care within three months [Hazards Ratio (HR)=0.89 (0.83, 0.96)] and after three months [HR=0.53 (0.46, 0.61)] of denture delivery, patients wearing both maxillary and mandibular RPDs [HR=0.67 (0.52, 0.87)], and patients receiving metal-based RPDs [HR=0.31 (0.23, 0.42)]., Conclusions: Metal-based dentures, dual arch restoration, and increased maintenance positively impact the survival of RPDs., Clinical Significance: Adapting consent and warranty practices is advised to reflect RPD performance variations., Competing Interests: Declaration of competing interest No conflict of interest was present at the time of preparing this manuscript. There is no internal or external funding to report., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Today, two different types of CAD-CAM fabrication methods for complete denture bases are available besides the conventional protocols: a subtractive milling process from a prepolymerized block of polymethylmethacrylate and an additive manufacturing process that built the denture base using a light-cured liquid in a VAT-polymerization process. The aim of this study was to evaluate and to compare the accuracy and precision of denture prosthetic bases made with subtractive and additive manufacturing technologies and to compare them with a denture base with the conventional method in muffle. From the results obtained, 3D printing dentures show a statistically significant higher accuracy than milled prosthetic bases. Milled prosthetic bases have similar accuracy than conventional fabricated dentures. [ABSTRACT FROM AUTHOR]

Professional, legal and ethical guidelines and rules guide the duties and responsibilities of dentists in relation to patient care, including the fabrication of removable partial dentures with cast clasp retained metal framework. The aim of our study was to assess the extent to which dentists follow these standards in the daily practice. Data were collected using a questionnaire and the responses of 88 dentists were analyzed. Based on our results, about half (54.5%) of the participating dentists send a precise denture design to the laboratory to be used in the preparation of a metal framework, 88.5% specify the abutment teeth, 65.9% choose the type of the clasps and 55.8% gives instructions for the major connectors. A small percentage of dentist provide information to the lab in drawing (8.1%), it is more common to send textual instructions (33.7%) and most dentists (58.2%) send drawings and written instructions together. Most of the dentists consider periodontal hygiene aspects (81.8%) and almost half of them (42.5%) consider that they send clear, precise instructions to the lab. A slightly higher proportion (50.5%) gives guidance but leaves more details to be decided by the dental technician and only 8% provide very little guidance and leaves most of the details to the dental technician. Dentists mostly (96.2%) use silicone impression material for the definitive impression to make the metal framework, only a few of them mentioned alginate. Dentists are largely willing to take responsibility in the event of an error and believe that planning together with the dental technician is important. To ensure that based on the patient-related information dentists always, or at least more often design the removable partial dentures with metal framework, the theoretical and practical knowledge needs to be broadened during university education and in continuing education courses.

Statement of problemIn patients with an altered skeletal maxillomandibular relationship and bone resorption, the rehabilitation of edentulous jaws by combining 4 implants, 2 straight medially and 2 tilted distally, may be preferred to avoid a bone augmentation procedure.PurposeThe purpose of this single cohort 1-year prospective study was to evaluate the clinical performance of a 4-implant overdenture fully supported by a computer-aided designed and computer-aided manufactured (CAD-CAM) titanium bar.Material and methodsThis single cohort prospective study included edentulous participants rehabilitated with a 4-implant overdenture in 1 of the 2 jaws. The outcomes were implant and prosthetic survival and success rates, any biologic and technical complications, periimplant marginal bone loss, changes in the oral health impact profile (OHIP), bleeding on probing, and the plaque index.ResultsEighteen participants received 72 implants. One year after implant placement, no implants or prosthesis had failed, and no biologic or technical complications had been observed. At the 1-year follow-up, the mean marginal bone loss was 0.29 ±0.16 mm. The OHIP summary scores demonstrated a significant improvement in oral health-related quality of life. At the 1-year follow-up, positive bleeding was found in 2 participants (11.1%) around 3 implants (4.1%). Three participants (16.6%), accounting for 5 implants (6.9%), showed a slight amount of plaque.ConclusionsA 4-implant overdenture supported by a CAD-CAM titanium bar may be a reliable option for the treatment of the edentulous mandible and maxilla over a 1-year period. Oral health-related quality of life significantly improved in all treated participants.

The aim was to discuss the indications, contraindications, advantages, and disadvantages of Nonmetal clasp dentures (NMCDs), as well as the most relevant properties of its constituent materials. A search was conducted using the keywords: “nonmetal clasp dentures,” “thermoplastic resin,” “flexible resin removable partial denture,” “polyamide,” and “nylon” in databases PubMed/Medline, Lilacs, SciELO, and textbooks between 1955 and 2020. Theses and texts without reliable sources of publication were excluded. Once the analysis instruments were determined, the data were analyzed and discussed. NMCDs present high flexibility, easy adaptation to the abutments, color compatibility and biocompatibility with the oral mucosa, and absence of visible metal clasps. However, they need laboratory relining, grinding, and polishing, do not have criteria for its planning, become rougher and stained over time, and are able to traumatize supporting tissues. The association with metal components seems to be an alternative to increase the success of NMCDs by combining esthetics and biomechanical principles of conventional removable partial dentures. The lack of long-term clinical studies makes the professionals to rely solely on previous experiences or on the manufacturers' recommendations. It suggested that NMCDs must be indicated with caution when not used temporarily.

Purpose: To evaluate the published literature on tooth-tissue supported removable partial dentures (RPDs) and determine the attachment system that provides the best clinical outcome., Materials and Methods: A comprehensive search of studies published up to November 2021 was performed in the PubMed/MEDLINE, Web of Science, and Cochrane Library databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. The study protocol was approved and was registered in the International Prospective Register of Systematic Reviews (PROSPERO: CRD42021268449). The PICO question was, 'What is the best attachment system used in Kennedy class I and II removable partial dentures?', Results: The search identified 871 articles, of which 21 met the inclusion criteria. The evaluation period in the studies ranged from 3 to 282 months. A total of 1,357 patients were included, of which 526 used prostheses with attachments. The mini SG attachment (extracoronal) was the most commonly used attachment, and the survival rate ranged from 37% to 98.1% in 10 studies, with no significant differences between the systems. Among the 10 studies selected for quantitative analysis, the meta-analysis revealed an overall failure rate of 16.6% (95% CI: 10.4% to 25.4%) and heterogeneity of I² &#61; 65.725 (q value: 26.258, P &#61; .002)., Conclusions: Clinical studies comparing different attachment systems for rehabilitation are lacking. Our findings suggest that attachment-retained RPDs have good retention and better esthetics than conventional RPDs, and the extracoronal attachment system is the most viable choice for treatment at the free end.

Background: Restorative treatment options for edentulous patients range from traditional dentures to fixed restorations. The proper selection of materials greatly influences the longevity and stability of fixed restorations. Most prosthetic parts are frequently fabricated from titanium. Ceramics (e.g. zirconia) and polymers (e.g. PEEK and BIOHPP) have recently been included in these fabrications. The mandibular movement produces complex patterns of stress and strain. Mandibular fractures may result from these stresses and strains exceeding the critical limits because of the impact force from falls or accidents. Therefore, it is necessary to evaluate the biomechanical behavior of the edentulous mandible with different restorations under different loading situations., Objective: This study analyzes the biomechanical behavior of mandibles after four prosthetic restorations for rehabilitation under normal and impact loading scenarios., Material and Methods: The mandibular model was constructed with a fixed restoration, which was simulated using various materials (e.g. Titanium, Zirconia & BIOHPP), under frontal bite force, maximum intercuspation, and chin impact force. From the extraction of tensile and compressive stresses and strains, as well as the total deformation of mandible segments, the biomechanical behavior and clinical situations were studied., Results: Under frontal bite, the anterior body exhibited the highest tensile (60.34 MPa) and compressive (108.81 MPa) stresses using restoration 4, while the condyles and angles had the lowest tensile (7.12 MPa) and compressive (12.67 MPa) stresses using restoration 3. Under maximum intercuspation, the highest tensile (40.02 MPa) and compressive (98.87 MPa) stresses were generated on the anterior body of the cortical bone using restoration 4. Additionally, the lowest tensile (7.7 MPa) and compressive (10.08 MPa) stresses were generated on the condyles and angles, respectively, using restoration 3. Under chin impact, the highest tensile (374.57 MPa) and compressive (387.3 MPa) stresses were generated on the anterior body using restoration 4. Additionally, the lowest tensile (0.65 MPa) and compressive (0.57 MPa) stresses were generated on the coronoid processes using restoration 3. For all loading scenarios, the anterior body of the mandible had the highest stress and strain values compared with the other segments. Compared to the traditional titanium restoration.2, restoration.1(zirconia) increases the tensile and compressive stresses and strains on the mandibular segments, in contrast to restoration.3 (BIOHPP). In addition, zirconia implants exhibited higher displacements than the other implants., Conclusion: In the normal loading scenario, the tensile and compressive stresses and strains on the mandible were within the allowable limits when all restorations were used. Under the chin impact loading scenario, the anterior body of the mandible was damaged by restorations 1 and 4., (© 2024. The Author(s).)