Surface topography and bacterial adhesion of CAD/CAM resin based materials after application of different surface finishing techniques

Aim: This study evaluated the surface topography and bacterial adhesion of a hybrid ceramic and a nano ceramic resin composite after different surface finishes. Methods: Hybrid ceramic (Vita Enamic, VITA - EN) and nano ceramic resin composite (Lava Ultimate, 3M/ESPE - LV) blocks of 12 x 14 x 18 mm were cut into 1 mm slices. Each slice was divided into four specimens (6 x 7 mm) that were randomly allocated into 4 groups (n=8) according to the surface finishing: CTL - without surface finish (control); DB - wear with a diamond bur; VT - polishing system for hybrid ceramic (VITA); and DD - polishing system for ceramics (Dedeco). The specimens were analyzed regarding surface roughness parameters (Ra, Rz, Rq), sterilized and subjected to bacterial adhesion. Representative specimens from each group were observed by SEM and Confocal Laser Scanning Microscopy. Data were submitted to two-way ANOVA and Tukey's test (α=0.05). Results: EN had lower surface roughness and bacterial adhesion than LV (p<0.05), regardless of the surface finish. The highest values for all roughness parameters was observed in LVDB group, differing from the other groups, which were not significantly different. Smaller bacterial adhesion values (CFU/mL) were observed for ENDD and ENVT, which differed significantly from the other groups, except ENCTL. For LV groups there was no significant difference between the different surface finishes (p>0.05). The type of material and surface finish system significantly interfered with surface roughness parameters and bacterial adhesion. The hybrid ceramic performed better after polishing than the nano-ceramic resin. Conclusion: An adequate finishing/polishing technique should always be performed after any kind of adjustment to indirect restorations made with these materials tested

Bacterial infiltration comparison of two root canal filling techniques

Introduction: Root canal system filling aims to the hermetic sealing of the space formerly occupied by the dental pulp. Objective: The aim of this study was to analyze the bacterial infiltration of Enterococcus faecalis in root canals filled through two techniques: single cone technique (group A) and thermoplasticized gutta-percha technique (group B). Material and methods: A total of 40 single-rooted human premolars were divided into two experimental groups (n = 15) and two control groups: positive (n = 5) and negative (n = 5). The root canals were prepared with ProTaper Universal system up to size F3 file and filled with the corresponding gutta-percha point. Teeth were mounted on a dual-chamber model, where the infiltration of E. faecalis was evaluated for a 30-day period by BHI turbidity indicating bacterial growth. Results: After the trial period all specimens in experimental and positive control groups showed turbidity of the culture medium. The average number of days until culture medium turbidity was 11.42 days for group A, 16.69 days for group B, and 5.5 days for positive control. By applying Anova test, there was no statistically significant difference between groups (p > 0.05). This allowed the observation that no difference between the obturation techniques in the infiltration of E. faecalis could be observed by the methodology used. Conclusion: It can be concluded that regardless of the obturation techniques, bacterial infiltration occurred.