Cervical Dentin Coverage and Brushing Resistance of Caries Preventive Coatings

Objectives: To analyze cervical dentin surface coverage and brushing resistance of two experimental and three commercial coating/sealing materials, indicated for caries prevention.
Methods: Dentin specimens (n=54) were prepared by embedding bovine incisor roots in polymethyl methacrylate, followed by fine grinding and polishing. Specimens were then randomly assigned to six groups: experimental hybrid-glass material without fluoride (Exp), with added fluoride (ExpF), Icon Vestibular (DMG) (Icon), Duraphat® Varnish (Colgate) (DpV), MI Varnish® (GC) (MIV) and no-treatment control (control). After smear layer removal by etching (15s, H₃PO₄) and 10-minute ultrasonic cleaning, materials were applied to cervical dentin according to the manufacturer’s instructions. Profilometric analysis of average roughness (Ra) (5 specimens/group, 5 measurements/specimen) and scanning-electron-microscopic (SEM) (2 specimens/group) analysis of materials’ dentin coverage and surface morphology were performed at baseline and after one-week brushing challenge with Oral-B-iO3 electric toothbrush.
Results: Brushing caused a significant increase in Ra in the control (p<0.001) and a significant decrease in Ra in DpV group (p<0.005). At baseline, all groups had significantly higher Ra than the control (p<0.05). DpV exhibited the highest Ra, followed by MIV and Icon, while Ra of Exp and ExpF was significantly lower than the other materials. After brushing, Exp and ExpF had significantly lower Ra compared to DpV and MIV, while remaining higher than control and no statistically different to Icon. SEM analysis revealed adequate dentin coverage for all materials both before and after brushing, with the exception of Exp, where dentin tubules were not fully sealed post-brushing. Post-brushing, only ExpF maintained its surface morphology, while other groups exhibited varying levels of surface deterioration.
Conclusions: The experimental fluoride-containing hybrid-glass material (ExpF) demonstrated superior performance compared to other tested materials. It effectively sealed cervical dentin and created the smoothest, most brushing-resistant coating.