Whitening gel and light source influence on pulp chamber temperature

Resumo

The chemical injury caused to the pulp by the penetration
of the whitening gel is already known, but another possible cause may
be the heat generated by the irradiation of the whitening gel with light
sources to accelerate the whitening reaction. Objective: To evaluate in
vitro the temperature increasing in the pulp chamber during in-office
bleaching with different gel concentrations and light sources. Material
and methods: A maxillary human central incisor was used in the 6
groups evaluated. The specimen was sectioned 3 mm apical to the
cementoenamel junction. The root canal and pulp chamber were cleaned
and widened with a diamond bur to receive the sensor of a thermocouple
thermometer. The following hydrogen peroxide gel concentrations were
evaluated: 35%, 25%, 15%, and 10%; and the following light sources
were applied: blue hybrid LED/laser and violet hybrid LED/laser. The
specimen bleaching was repeated 6 times per group. As a control,
the temperature was measured with the application of light, without
applying any gel. Results were evaluated with one-way ANOVA and
Tukey’s test (α = 5%). Results: Significant differences between groups
were observed (p < 0.05). The blue LED without the gel induced the
smallest heat (37.5 ± 0.2) and the blue LED with 15% gel caused the
highest heat (38.2 ± 0.3). The combination of violet LED with the 10%
gel caused no significant increase in temperature compared to the
control in which light was used without gel (p> 0.05). Conclusion: No
increase in pulp chamber temperature was higher than 2°C.