The tested parameters of 980-nm diode laser promoted similar alterations on dentine morphology, dependent to the type of surface pretreatment.

This study evaluated the influence of bleaching protocols on intrapulpal temperature and fracture strength of the bleached teeth. Ninety maxillary incisors were assigned to 9 groups (n=10): G1: 35% carbamide peroxide (35% CP), G2: 38% hydrogen peroxide (38% HP), G3: halogen light, G4: LED-laser, G5: 35% CP + halogen light, G6: 38% HP + halogen light, G7: 35% CP + LED-laser, G8: 38% HP + LED-laser, and G9: no treatment (control). Pulp space was widened, a thermocouple was introduced through the apex up to the pulp chamber and the temperature was recorded (°C). The fracture strength (kN) was determined using an Instron machine. Data were analyzed by ANOVA and Tukey's test (p<0.05). The halogen light alone (1.10 ± 0.24) (G3) and associated with 38% HP (1.15 ± 0.30) (G6) produced the highest temperature increase, statistically different (p<0.05) from the other groups. G1 (0.15 ± 0.06) and G6 (0.19 ± 0.07) produced the lowest values, statistically different (p<0.05) from G5 (0.65 ± 0.49). The bleaching protocols increased the temperature, but no increment exceeded the critical value of 5.6°C. Neither 35% CP nor 38% HP or the light sources alone altered the fracture strength of the teeth.

The aim of this study was to evaluate the cleaning capacity of Profile .04 files combined with different irrigating solutions in flattened root canals using histological, morphometrical and SEM analyses. Eighty human mandibular incisors were prepared with Profile .04 instruments and randomly divided into 4 groups according to the irrigating solutions used (n=20): G1: distilled water (control); G2: 1% sodium hypochlorite (NaOCl); G3: 1% NaOCl alternated with 17% EDTA, and G4: 1% NaOCl with RCPrep cream. Ten teeth of each group were evaluated with an optical microscope to determine the percentage of root canal debris. The remaining teeth were evaluated under scanning electron microscopy (SEM). Data were analyzed statistically by ANOVA and Tukey's test (alpha=0.01).There was a significant difference (p<0.001) among the groups regarding the percentage of debris left in the canals (distilled water: 18.82 +/- 5.55; 1% NaOCl: 6.29 +/- 5.55; 1% NaOCl + 17% EDTA: 12.47 +/- 6.92; 1% NaOCl + RCPrep: 7.82 +/- 1.91). The SEM analysis showed the best results for 1% NaOCl + 17% EDTA on smear layer removal. It may be concluded that the combination of Profile .04 rotary instrumentation and the tested solutions was not able to totally remove debris and smear layer from flattened root canals.