TiF₄ Gel Effects on Surface Morphology of Eroded Human Dentin

Objectives: This study aimed to evaluate the effects of TiF₄ gel on the surface morphology of dentin submitted to erosion/abrasion in situ.
Methods: Seventy dentin samples were obtained from human third molars. Sixty samples were eroded in vitro and allocated into 6 groups (n=10) according to the surface treatment received during the in situ phase and the number of erosive/abrasive cycles, as follows: TiF₄ gel (4%) applied once (TiF₄1), twice (TiF₄2) or three times (TiF₄3) followed by 1, 2 and 3 erosive/abrasive cycles, respectively. Control groups were subjected to 1 (C1), 2 (C2) and 3 (C3) erosive/abrasive cycles only. The seventh group (n=10) comprised in vitro uneroded samples (UN) that were subjected to 3 erosive/abrasive cycles. For each cycle, there were 2 days of erosive (0.5% citric acid, pH 2,6, 6x/day) and abrasive (1x/day) challenges. Examiners blinded to the study assessed occlusion by visual score (0 – unoccluded, 1 – partially occluded by deposition, 2 – partially occluded by reduction in tubular lumen, 3 – occluded) of environmental scanning electron microscopy (ESEM) micrographs taken before and after the in situ phase.
Results: Kruskal-Wallis test and pairwise comparisons were performed (α=0.05). The results showed that the pattern of tubule occlusion was more evident in UN group (50.90), which did not differ statistically from C3 (42.40) and TiF₄3 (41.55) groups (p=0.0142). The pattern with the least tubular occlusion was observed in groups subjected to lower amounts of erosive/abrasive cycles. However, the pattern of occlusion observed in the micrographs reveals that, in groups treated with the TiF₄ gel, the tubular occlusion occured by the decreasing in the lumen diameter, while for the control groups, the morphology showed deposits on the surface or layer of demineralized organic matrix.
Conclusions: Therefore, it may be suggested the TiF₄ was able to positively change the surface morphology of the dentin samples.