The Impact of Repeated Steam Sterilization Cycles on the Efficacy of Chairside Adjustment Kits for Polishing Monolithic Multi-Layered Zirconia Dental Restoration Material.

BACKGROUND Before insertion, chairside adjustment kits are heat sterilized for positioning and polishing dental restorations. This study aimed to evaluate the effects of 2 steam sterilization cycles on the efficacy of polishing highly translucent monolithic zirconia (HTMLZ) dental restoration material. MATERIAL AND METHODS 100 HTMLZ disc-shaped specimens were adjusted (grinding, finishing, polishing) with EVE Diacera kit. Two steam sterilization techniques [standard (Gp S), immediate/flash (Gp (F)] of CAK were further subgrouped based on number of sterilization cycles [cycle 1 (control), cycle 5, 10, 15, and 20 (experimental)] (n=10 each). Each subgroup accordingly was evaluated for average surface roughness (Ra) and root mean square roughness (Rq) using a profilometer. Mean and standard deviation of 5 subgroups were statistically analyzed using one-way ANOVA/post hoc Tukey's test. Scanning electron microscopy complemented Ra, Rq measurements. Statistical differences of P≤0.05 were considered significant. RESULTS HTMLZ specimens in both groups showed increased (Ra/Rq) values after repeated sterilization of EVE Diacera kit, with Gp F showing lesser increase than Gp S (20 cycles). Gp F at 10 cycles and Gp S at 15 cycles showed clinically unacceptable roughness threshold (0.25 µm). Differences between subgroups for Ra and Rq values were significant (P≤0.05) with less differences within groups observed in early cycles (1, 10). Results validate the manufacturer's recommendations of using flash sterilization/10 cycles for EVE Diacera kit. CONCLUSIONS Repeated sterilization reduces efficacy of chairside adjustment kit to produce smooth surfaces on HTMLZ. This study recommends flash sterilization to a maximum of 10 times to get the clinically acceptable results of Ra and Rq.

Evaluation of the Effects of Digital Manufacturing, Preparation Taper, Cement Type, and Aging on the Color Stability of Anterior Provisional Crowns Using Colorimetry.

BACKGROUND Replicating the 3-dimensional (3D) color of natural teeth in artificial substitutes is challenging. Fixed dental prosthodontics require aesthetic, color-stable provisional restorations. Recent milling and 3D printing digital manufacturing techniques offer improved outcomes. This study assesses color stability in various digital manufacturing methods, tapers, and aging effects on anterior provisional resin restorations. MATERIAL AND METHODS Two all-ceramic tooth preparations on typodont teeth with 10° and 20° tapers were converted into experimental dies. Forty temporary crowns were manufactured using 3D printing and computer-aided design/computer-aided manufacturing (milling). Within these 2 groups, 10 crowns were cemented using a regular and clear provisional cement. All samples were thermocycled to simulate clinical use of 6 months. Color difference formula (CIEDE2000) indicated changes between before and after cementation (ΔE00) and between after cementation and after thermocycling (ΔE00[II]). The color change was considered significant in terms of clinically perceptible (ΔE00 ≤0.62) and acceptable (ΔE00 ≤2.62) changes. One-way ANOVA (P value of less than 0.05) calculated overall differences, which were established using a Fisher post hoc test. RESULTS Crowns cemented with clear cement showed fewer color changes irrespective of the manufacturing technique or taper. Notably, only the 10° 3D-printed crown with clear cement had an imperceptible color change at the pre-/post-cementation phase. Meanwhile, the 10° and 20° milled crowns with regular cement exhibited unacceptable color changes after thermocycling. CONCLUSIONS For long­term temporization in the aesthetic zone, properly optimized 3D-printed provisional restorations cemented with clear cement had better color stability.

Effects of Smokeless Tobacco on Color Stability and Surface Roughness of 3D-Printed, CAD/CAM-Milled, and Conventional Denture Base Materials: An In Vitro Study.

Tobacco consumption in its different forms can affect the optical and surface properties of dental materials that are used in the oral cavity. Thus, the present study was conducted to evaluate the effects of two commercially available smokeless tobacco products on the color stability and surface roughness of denture base resins that were fabricated using three different techniques (CAD/CAM milling, 3D printing, and conventional heat polymerization). A total of 126 denture base resin specimens were fabricated using the three different manufacturing techniques (n = 42 each). Specimens from each group were further subdivided into three subgroups (n = 14 each) and immersed in three different immersion media (a khaini suspension, a tabbaq suspension, and artificial saliva). The differences in color and surface roughness were assessed according to data that were collected and statistically analyzed using SPSS version 24.0. The tabbaq smokeless tobacco was found to cause greatest changes in color and surface roughness; the effect was observed to be highest in the 3D-printed specimens followed by the conventional heat-polymerized and CAD/CAM milled specimens. The mean changes in color and surface roughness were the highest for the tabbaq smokeless tobacco followed by the khaini smokeless tobacco and the artificial saliva. Statistically significant (p-value < 0.05) differences were observed among all techniques and suspensions. We concluded that the mean changes in color and surface roughness were significantly higher for the 3D-printed dentures compared to the conventional heat-polymerized and CAD/CAM-milled dentures. Thus, the results of the present study strengthened the concept that tobacco in any form can lead to changes in the color and surface roughness of denture base materials.

Emotional, behavioral, and social effects of anterior tooth loss: a cross-sectional study / Efeitos emocionais, comportamentais e sociais da perda dentária anterior: um estudo tranversal

Objective: The study aims to evaluate the emotional, behavioural, and social effects of single or multiple anterior tooth loss. It also compares the effectiveness of the removable and fixed prosthesis to address the impact of anterior tooth loss. Material and Methods: The study was carried out on 70 subjects who presented to the Department of Prosthetic Dental Sciences. A questionnaire was distributed and the data were statistically analyzed using SPSS version 18.0 and values less than 0.05 % were considered statistically significant. Results: The participant's difficulty to accept loss of their anterior tooth, embarrassment and confidence were changed significantly after wearing the prosthesis (P< 0.05). Moreover, fixed partial denture had more effect than removal partial denture. It was claimed by 62.9% of the participants that they were not prepared for the effect of tooth loss and 47.1% of them thought that a prior explanation from the dentist would have helped them overcome their fear of losing their teeth. Conclusion: The maximum impact of anterior tooth loss was felt on confidence followed by embarrassment. The participants felt more comfortable after wearing their prosthesis. Fixed partial denture had more effect than removable partial denture.(AU)

Objetivo: O estudo visa avaliar os efeitos emocionais, comportamentais e sociais da perda dentária anterior unitária ou múltipla. Ele também compara a eficácia da protese removível e da fixa para lidar com o impacto da perda dentária anterior. Material e Métodos: O estudo foi realizado em 70 indivíduos que se apresentaram ao Department of Prosthetic Dental Sciences. Foi distribuído um questionário e os dados analisados estatisticamente no SPSS versão 18.0 e valores inferiores a 0,05% foram considerados estatisticamente significativos. Resultados: A dificuldade do participante em aceitar a perda de seu dente anterior, constrangimento e confiança mudaram significativamente após usar a prótese (P <0,05). Além disso, a prótese parcial fixa teve mais efeito do que a prótese parcial removível. Foi alegado por 62,9% dos participantes que não estavam preparados para o efeito da perda dentária e 47,1% deles achavam que uma explicação prévia do cirurgião-dentista os teria ajudado a superar o medo de perder os dentes. Conclusão: O impacto máximo da perda dentária anterior foi sentido na confiança, seguido de constrangimento. Os participantes se sentiram mais confortáveis após o uso de suas próteses. A prótese parcial fixa teve mais efeito do que a prótese parcial removível (AU)