Validation of pH cycling model to induce artificial carious lesions in bovine dentin

Resumo

The purpose of the study was to
evaluate different pH cycling protocols on the induction of artificial
carious lesions in bovine dentin, since the most appropriate protocol
to be applied is still not fully established. Material and methods:
Fragments of bovine dentin (4 x 4 x 2 mm) were embedded in resin,
polished and 7 mm² of each fragment was isolated with wax. The
specimens were divided into three groups (A, B, C) according to the
time of immersion in the demineralizing solution (1.5 ml). Group A
– 15 minutes; Group B – 30 minutes; Group C – 60 minutes and
subsequently immersed for 22 hours in a remineralizing solution (1.5
ml). Microhardness measurements were conducted initially, daily and
after each pH cycling for 4 days. The Split-plot design (ANOVA) was
applied. Results: There was a significant interaction between time
and cariogenic challenge (p<0.0001). Bonferroni comparisons were
executed to identify the differences over the cariogenic challenge,
showing that increasing the immersion time in demineralizing solution
for each pH cycling assessed, the cariogenic challenge aggressiveness
increased (A <B <C). Also, for each protocol tested there was a
significant decrease in the hardness in the cariogenic challenge over
the time. Conclusion: The three models tested proved to be viable,
regardless of the time of cariogenic challenge that was applied.