Characterization of Contemporary Conventional, Bulk-fill, and Self-adhesive Resin Composite Materials.

OBJECTIVE: To evaluate the physical and biological properties of different types of flowable resin composites and their bonding ability to dentin, comparing the performance of self-adhesive and bulk-fill materials with a conventional control. METHODS AND MATERIALS: Four flowable resin composites were tested: two self-adhesive (Y-flow [SA_YF]; and Dyad Flow [SA_DF]); one bulk-fill (Filtek Bulk Fill Flow [BF]); and one conventional composite (Opallis Flow [OF]). The microshear bond strength (µSBS) to dentin (bovine samples) was investigated at 24 hours and 6 months of storage. The materials were also characterized by degree of conversion, cross-link density, water contact angle, color stability, and cell viability (ISO 10993-5/2009) analyses. Data were analyzed using Analysis of Variance and Tukey tests (α=0.05). RESULTS: The µSBS values were higher for control specimens at 24 hours, whereas the resin-dentin bonds were similarly distributed among the groups after aging. Adhesive failure was the most frequent pattern observed at both time intervals. SA_YF was the only material that increased the bond strength over time. Degree of conversion increased in the following order: SA_YF (28.6±1.4%) < BF (49.7±0.8%) < OF (60.0±2.0%) = SA_DF (63.6±2.3%). Cross-link density was similar among all materials. The self-adhesive composites were more hydrophilic than the other types, with BF showing the lowest water contact angle and the greatest color alteration. All resin composites had a biocompatible behavior. CONCLUSION: Chemical composition appeared to be an influential factor affecting the physico-mechanical and biological behavior of the materials tested.

Photobiomodulation therapy reduces postoperative pain after third molar extractions: A randomized clinical trial.

BACKGROUND: To assess the efficacy of PBMT on reducing postoperative pain scores in patients submitted to third molar extractions. MATERIAL AND METHODS: A randomized controlled trial (ReBEC:RBR-94BCKZ) was designed according to the SPIRIT and followed the CONSORT. Patients were randomly allocated according to control or PBMT groups. PBMT consisted of the application of GaAlAs laser (808nm;50mW) applied in six points (1.23 min;11 J/cm2) after extraction. Pain scores were assessed using the Visual Analogue Scale (VAS) in millimeters evaluated after 6 (T6), 24 (T24), and 48 (T48) hours. The Wilcoxon Mann-Whitney test was used to check for possible associations between VAS scores and treatment groups. RESULTS: A total of 101 third molar extractions were performed in 44 patients. The mean age was 28 years old(SD±11.54). Comparing control and intervention, PBMT group showed a significant effect on the reduction of postoperative pain at T6(mean VAS=0.9; C.I:0.63-1.16) compared to control (mean VAS=2.5;C.I:2.1-2.88)(p<0.001). The same statistically significant effect on the reduction of postoperative pain was observed at T24 (PBMT mean VAS=0.72;C.I:0.51-0.93; control mean VAS=2.86;C.I:2.40-3.31;p<0.001) and T48 (PBMT mean VAS=0.64;C.I:0.36-0.92; control mean VAS=2.86;C.I:2.37-3.34;p<0.001). CONCLUSIONS: PBMT significantly reduce the postoperative pain scores when assessed 6, 24, and 48 hours after third molar extractions.