Objectives: The disinfection of fabricated prostheses is crucial to prevent cross-infection between dental laboratories and clinics. However, there is a lack of information about the effects of chemical disinfection on 3D-printed denture base resins. This study aimed to evaluate the impact of different disinfectants on the flexural strength, elastic modulus, micro-hardness, surface roughness (Ra), and change in color of 3D-printed and conventional heat-polymerized (HP) denture base resins (DBRs). Methods: A total of 240 specimens (80 bar-shaped (64 × 10 × 3.3 mm) and 160 disk-shaped (10 × 2 mm)) were made from HP and 3D-printed DBRs. For each resin, the specimens were divided into four groups (n = 10) according to the disinfectant solution. One remained in water without disinfection as a control group, while the other three groups were disinfected using 1% sodium hypochlorite, 2% glutaraldehyde, or 10% Micro 10+ for 30 min. The flexural strength, elastic modulus, micro-hardness, Ra, and color change were measured. The collected data were statistically analyzed using a two-way ANOVA and Tukey’s post hoc test (α = 0.05). Results: A significant decrease in flexural strength, elastic modulus, and hardness was found with sodium hypochlorite (p < 0.05). When comparing the resins per solution, the 3D-printed resin showed a significant decrease in flexural strength, elastic modulus, and hardness compared with PMMA (p < 0.001), while no change was found in the Ra of both resins with all disinfectants (p > 0.05). Disinfecting with sodium hypochlorite resulted in a significant increase in color change for both resins (p < 0.05); however, all the changes were within clinically acceptable limits. Sodium hypochlorite showed the highest color change, while 2% glutaraldehyde and 10% Micro 10+ showed no significant changes in the tested properties (p > 0.05). Conclusions: Neither resin showed a change in surface roughness with immersion in disinfectants. Sodium hypochlorite had an adverse effect on the flexural properties, hardness, and change in color of the PMMA and 3D-printed DBRs, while the other disinfectants had no effect on the tested properties.

Objective: the study aimed to ascertain the pattern and the prevalence of partial edentulism among Egyptian patients. Materials and Methods: An observational cross-sectional study was conducted by screening patients attending out-patients clinics of three prosthodontics departments of dental faculties in Egypt. The prevalence of partial edentulism among all patients was recorded. Patients were grouped into four groups according to the age into Group I: 21–30 years, Group II: 31–40 years, Group III: 41–50 and Group IV: over 50 years. The pattern of partly edentulous arches was identified using Kennedy's classification. To eliminate the complexity, the assessment did not consider the modification areas. Data was analyzed using IBM SPSS Statistics for Windows, Version 23.0: IBM Corp. Results: Kennedy Class I partial edentulism was 30.92%,(17.83 ,13.09) in the mandible and the maxilla, followed by class III that was 30.73%,(17.73 ,13.00) in the mandible and the maxilla, followed by class II that was 27.11%,(15.60 ,11.51)in the mandible and the maxilla,and finally class IV was 11.23%,(6.04 ,5.20)in the mandible and the maxilla and Kennedy’s Class III was the most common partially edentulous pattern (11.05 %,9.56%) between ages (20-30 and 31-40) years , Kennedy’s Class I,II was the most common partially edentulous pattern (12.81 %,7.99 %) (11.33%,9.10%,) between ages (41-50)(over50) years. Conclusions: With increasing age, there is a rise in Classes I , II ,IV Kennedy classification and a drop in Classes III. Class III was more prevalent in the younger population, but Class I was more prevalent in elder patients.

Background/Objectives: This in vitro study evaluated the wear resistance and fracture load of newly introduced ceramic-reinforced hybrid 3D-printed permanent resin tooth materials and compared their mechanical performance with prefabricated polymethylmethacrylate denture teeth and a conventional 3D-printed resin tooth material. Methods: Mandibular first molars were digitally scanned in an anatomic form for fracture load testing and a flattened occlusal form for wear depth evaluation. Four 3D-printed materials were fabricated: one conventional 3D-printed resin (NextDent C&B MFH) and three ceramic-reinforced hybrid resins (VarseoSmile, Crowntec, and Flexcera Smile). Half the specimens underwent thermal cycling (10,000 cycles). Wear testing was performed in a chewing simulator using a ceramic antagonist under 49 N for 120,000 cycles. Wear depth (µm) was quantified with 3D deviation analysis using Geomagic software. Fracture load was measured using a universal testing machine. Data were analyzed using two-way ANOVA and Tukey post hoc comparisons (α = 0.05). Results: Ceramic-reinforced hybrid materials exhibited significantly lower wear depth and higher fracture load values than prefabricated polymethylmethacrylate and conventional 3D-printed resin tooth materials before and after thermal cycling (p < 0.001). Conventional 3D-printed resin tooth materials consistently showed the greatest wear depth and lowest fracture load. Thermal cycling significantly reduced mechanical performance in all groups. Conclusions: Under the present in vitro conditions, ceramic-reinforced hybrid 3D-printed resin tooth materials demonstrated superior wear behavior and fracture resistance to prefabricated and conventional 3D-printed resin tooth materials.