The effect of phytosphingosine associated with tooth brushing on color change, surface roughness, and microhardness of dental enamel - an in vitro and in situ study.

Objective: This study evaluated the in vitro and in situ effects of phytosphingosine (PHS) associated with tooth brushing on color stability, surface roughness, and microhardness of dental enamel.
Methods: Sixty-four specimens of bovine teeth (6 × 6 × 2 mm) were separated into 8 groups (n = 8): S + TB: PHS (spray) + tooth brushing; TB + S: tooth brushing + PHS (spray); I + TB: PHS (immersion) + tooth brushing; TB + I: tooth brushing + PHS (immersion); TB: tooth brushing; S: PHS spray; I: immersion in PHS solution, and Saliva: immersion in saliva. Tooth brushing simulation (Mavtec, Brazil) was performed (356 rpm on 3.8 cm area by the toothbrush - Soft Tek) for 1, 7, 15, and 30 days. PHS remained in contact with specimens for 15 min. The specimens were evaluated before and after tooth brushing for color alteration (Easy Shade, VITA), and surface roughness (Model SJ-201P Mitutoyo), and Knoop microhardness (HMV-2, Shimadzu Corporation). For the in situ analyses, 8 participants were recruited and received an intraoral device with 6 fragments of bovine enamel (6 × 6 × 2 mm). The properties evaluated were the same as those of the in vitro study. Participants were randomized following best results of in vitro tested protocols, for 15 days: TB, TB + S, I + TB. Data obtained by in vitro (two-way ANOVA, Tukey, p < .05) and in situ (one-way ANOVA, Tukey, p < .05) studies were analyzed.
Results: The in vitro study showed that greater color change was found after 30 days. The greatest differences in surface roughness occurred between the initial value and after 1 day. Regarding microhardness, the highest values occurred after 15 and 30 days, which showed similar results. The in situ study showed greater color changes for the TB and I + TB, and greater surface roughness changes for TB as well as a similar increase in microhardness for the PHS protocols, which were higher than TB.
Conclusions: Phytosphingosine leads to an increase in performance regarding color stability, surface roughness, and microhardness when applied. In general, the application of PHS after brushing showed a positive impact on its performance.
Clinical Relevance: Phytosphingosine proved to be interesting for compound prevention formulations in the dentistry field.
(© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)