Brushing Resistance of Orthodontic Sealants – An in Vitro Surface Analysis Study Using Two Different Profilometric Evaluation Methods

Background: The aim of this study was to investigate the mechanical resistance of five commonly used orthodontic sealants against brushing load in comparison to a positive group. Methods: Brackets were bonded to each of the 48 hydroxyapatite (HA) discs, and then divided into 6 groups of 8 specimens. No human subjects were involved. The following sealants were applied around the bracket base and according to manufacturer’s instructions. Group 1: Pro SealTM (Reliance Orthodontic Products, Itasca, Illinois, USA); 2: Light BondTM (Reliance Orthodontic Products, Itasca, Illinois, USA); 3: ClinproTM XT Varnish (3M ESPE, Seefeld, Germany); 4: Protecto® CaF2 Nano (BonaDent GmbH, Frankfurt am Main, Germany); 5: Fluor Protector (Ivoclar Vivadent AG, Schaan, Liechtenstein). Tetric EvoFlow® (Ivoclar Vivadent AG, Schaan Liechtenstein) was used as the positive control group.Tooth brushing simulations of 6 weeks and 6 months were performed with the Oral-B PRO 1000 electric toothbrush (Procter & Gamble Manufacturing, Marktheidenfeld, Germany). The quantity of each sealant was measured with mechanical (MP) and optical profilometry (OP), at baseline, after 6 weeks and after 6 months of brushing. Statistical analysis was performed according to two mixed linear models and post hoc Tukey-Kramer comparisons. The significance level was set at 5% (α ≤ 0.05).Results: Pro SealTM (MP: 9%; OP: 22%) and Light BondTM (MP: 19%; OP: 16%) showed the lowest changes in sealant thickness after 6 months of simulated brushing. ClinproTM XT Varnish and Tetric EvoFlow® recorded no statistically significant results. The fluoride varnishes Protecto® CaF2 Nano and Fluor Protector could not be conclusively evaluated since the thickness of the sealants could not be determined at baseline. The results of both evaluation methods are in good agreement.Conclusion: Pro SealTM and Light BondTM are resistant against tooth brushing and are able to adequately keep the bracket environment sealed even after 6 months. The two different measuring methods, MP and OP, provide a precise impression of the changes in the surface.