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Purpose: To compare the influence of surface roughness and accelerated aging on the mechanical properties of polymer-based and ceramic CAD/CAM materials.Materials and Methods: Three polymers (Lava Ultimate [LVU], VITA ENAMIC [ENA], and Shofu Block HC [SFB]) and one ceramic (IPS Empress CAD [EMP]) were selected for this study. The specimens were treated with the aim of measuring surface roughness (Ra [mm]) and its influence on the mechanical properties. The treatments were: polishing (POL); etching with 9.6% hydrofluoric acid for 90 seconds (ETC); airborne-particle abrasion with 50-μm aluminum oxide at 2-bar pressure (SBT); and airborne-particle abrasion with 50-μm aluminum oxide at 2-bar pressure plus etching with 9.6% hydrofluoric acid (SAC) for 90 seconds. Before and after the accelerated aging (AA) protocol (30,000 cycles, 5°C and 55°C), the specimens were subjected to the 3-point bending test. The data were analyzed with two-way and three-way ANOVA and post hoc Tukey test (P < .05).Results: The surface roughness ranged from 0.24 μm to 1.96 μm, with statistically significant differences (P < .05). The highest surface roughness, in descending order, was exhibited by: LVU > SFB > EMP > ENA. The AA demonstrated an influence on the flexural strength of LVU, ENA, and SFB. The surface treatment did not affect the flexural moduli of the materials tested. The LVU and SFB showed decreased moduli of resilience after the AA; however, modulus of resilience was not influenced by surface treatment.Conclusion: The polymer-based materials were affected by AA. In addition, surface treatment could jeopardize their mechanical properties in certain conditions. [ABSTRACT FROM AUTHOR]

Purpose: This cross-sectional study was performed to determine whether an association exists between the width of keratinized mucosa and the health of implant-supporting tissues. Materials and Methods: Data on 200 dental implants were collected. Periodontal parameters measured included Plaque Index, Gingival Index, width of keratinized mucosa, thickness of keratinized mucosa, radiographic bone level, and bleeding on probing. Statistical analysis was accomplished with the t test, Wilcoxon rank sum test, and logistic and linear regression models. Significance was established when P was less than .05. Results: The mean Gingival Index score, Plaque Index score, and radiographic bone loss were significantly higher for those implants with a narrow zone (< 2 mm) of keratinized mucosa. Implants with a narrow zone of keratinized mucosa also were more likely to bleed upon probing, even after adjusting for Plaque Index, smoking, thickness of the gingiva, and time since implant placement (adjusted odds ratio, 2.37; 95% confidence interval, 1.04 to 5.83). Significant independent association also was found between the width of keratinized mucosa and radiographic bone loss in favor of wider zone of keratinized mucosa. Conclusion: Increased width of keratinized mucosa around implants is associated with lower mean alveolar bone loss and improved indices of soft tissue health. [ABSTRACT FROM AUTHOR]