Effects of artificial aging on the bond strengths of universal dental adhesives.

AIMS: The effect of mechanical loading on the microtensile bond strength (µTBS) of universal adhesives to dentin was evaluated in this study. METHODS AND MATERIALS: Human molar teeth had the occlusal dentin surfaces exposed and were allocated into ten groups (five experimental groups and five control groups) that used the following universal adhesive systems in self-etch mode: All-Bond Universal (ABU), Single Bond Universal (SBU), Gluma Bond Universal (GBU), Tetric N-Bond Universal (TBU), and Clearfil Universal Bond (CUB). Following the bonding procedures and build-ups, the specimens were either stored in water at 37°C for 24 h or were mechanically loaded (50 N for 60,000 cycles) prior to the µTBS test. Data were analyzed using the one-way analysis of variance (ANOVA) and Tukey's posthoc test (P = 0.05). RESULTS: Both the adhesive type and mechanical loading had significant effects on the µTBS (P < 0.05). The µTBS values of SBU and ABU were significantly higher than the values of the other adhesives (P < 0.05). However, the µTBS values of ABU decreased significantly after mechanical loading (P < 0.05). CONCLUSIONS: With the exception of ABU, mechanical loading had no deleterious effects on the µTBS of the universal adhesive systems examined in this study.

A five-year clinical evaluation of direct nanofilled and indirect composite resin restorations in posterior teeth.

AIM: To assess the clinical efficacy of posterior composite resin restorations placed directly and indirectly in posterior teeth after five years. MATERIALS AND METHODS: A total of 108 cavities in 54 patients were restored with three direct composite resins (Filtek SupremeXT [FSXT], Tetric Evo Ceram [TEC], AELITE Aesthetic [AA]) and two indirect composite resins (Estenia [E] and Tescera ATL [TATL]). All restorations were evaluated by two examiners using the United States Public Health Service criteria at baseline and five years after placement. Statistical analysis was completed with Fisher exact and McNemar χ(2) tests. RESULTS: At baseline, 4% (five) of the restored teeth presented postoperative sensitivity; however, only one of them (a member of the E group) required canal treatment and replacement after two years. At the five-year evaluation, all restorations were retained, with Alpha ratings at 100%. Only one tooth (in the TEC group) required replacement after three years due to secondary caries. Color match, surface texture, and marginal integrity were predominantly scored as Alpha after five years for all groups. After that time, marginal discoloration was scored as Alpha in 64% of AE restorations, 70% of TATL restorations, 73% of E restorations, and 87% of FSXT restorations. There were no Charlie scores recorded for any of the restorative systems. CONCLUSIONS: Under controlled clinical conditions, indirect composite resin inlays and direct composite resin restorations exhibited an annual failure rate of 2.5% and 1.6%, respectively, after five years. Therefore, the investigated materials showed acceptable clinical performance, and no significant differences were found among them.

The effect of calcium silicate-based sealer on the push-out bond strength of fibre posts.

BACKGROUND: The aim of this study was to assess the effect of the iRoot SP root canal sealer on the push-out bond strength of fibre posts cemented with self-adhesive resin cement. METHODS: Forty-eight extracted maxillary incisors were randomly divided into four groups according to the tested sealer (n = 12): group 1 - control (only gutta-percha points, no sealer); group 2 - AH Plus Jet (resin-based sealer); group 3 - Endofill (zinc oxide-eugenol-based sealer); and group 4 - iRoot SP (calcium silicate-based sealer). All root canals were filled with gutta-percha, and groups 2-4 additionally received one of the sealers. Fibre posts were cemented with the self-adhesive resin cement Clearfil SA Cement. The specimens were sectioned in the coronal, middle and apical regions, producing three slices of 1 mm thickness. The push-out test was performed. All data were submitted to ANOVA and Tukey tests (α = 0.05). RESULTS: No statistically significant differences were found between the control group, AH Plus Jet and iRoot SP (p > 0.05). The Endofill sealer showed significantly lower bond strength compared to the other sealers and the control group (p < 0.05). CONCLUSIONS: The calcium silicate-based sealer did not adversely affect the bond strength of the fibre posts cemented with self-adhesive resin cement.