Objectives:The aim of this study was to evaluate the intrapulpal temperature variation after bleaching treatment with 35% hydrogen peroxide using different sources of activation.Material and Methods:Twenty-four human teeth were sectioned in the mesiodistal direction providing 48 specimens, and were divided into 4 groups (n=12): (G1) Control - Bleaching gel without light activation, (G2) Bleaching gel + halogen light, (G3) Bleaching gel + LED, (G4) Bleaching gel + Nd:YAG Laser. The temperatures were recorded using a digital thermometer at 4 time points: before bleaching gel application, 1 min after bleaching gel application, during activation of the bleaching gel, and after the bleaching agent turned from a dark-red into a clear gel. Data were analyzed statistically by the Dunnet's test, ANOVA and Tukey's test (α=0.05).Results:The mean intrapulpal temperature values (°C) in the groups were: G1: 0.617 ± 0.41; G2: 1.800 ± 0.68; G3: 0.975 ± 0.51; and G4: 4.325 ± 1.09. The mean maximum temperature variation (MTV) values were: 1.5°C (G1), 2.9°C (G2), 1.7°C (G3) and 6.9°C (G4). When comparing the experimental groups to the control group, G3 was not statistically different from G1 (p>0.05), but G2 and G4 presented significantly higher (p<0.05) intrapulpal temperatures and MTV. The three experimental groups differed significantly (p<0.05) from each other.Conclusions:The Nd:YAG laser was the activation method that presented the highest values of intrapulpal temperature variation when compared with LED and halogen light. The group activated by LED light presented the lowest values of temperature variation, which were similar to that of the control group.

Objective: To determine the time required for pH buffering by saliva after use sugary(S), sugar-free (SF) and probiotic (P) chewing gums. Material and Methods: Saliva was collected from 12 volunteer dental students at UNESP São José dos Campos / SP, in order to determine salivary flow (SR) rate and initial buffering capacity (BC). Participants presenting BC>4.0 were invited to continue the research. Participants chewed different types of gum for 3 consecutive days, and saliva was collected at 0-1min, 1-5min, and 5-10min intervals. The time required to neutralize saliva pH after chewing the different types of gum was analyzed by RM ANOVA and Tukey's test (5%). Results: RM ANOVA revealed significant influence on the interaction effect (chewing gum and time) (statisticFdf(4.66) = 4.027, p = 0.0055 <0.05). According to Tukey's test, differences were observed in the following circumstances: for the 0-1 interval, BC of S differs from SF and P; BC of S differs from SF at 1-5 min and 5-10 min intervals; and, 0-1min interval differs from 1-5 min and 5-10 min intervals for both S and SF. Conclusion: Dentistry students showed no increased predisposition to dental caries with a specific type of chewing gum. Although time for pH recovery differed according to gum type, they were all above the critical range for enamel demineralization.

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