Dentin tubule occlusion and erosion protection effects of dentifrice containing bioadhesive PVM/MA copolymers

Abstract

To study the effectiveness of a dentifrice containing polyvinylmethyl ether-maleic acid (PVM/MA) copolymer in occluding dentin tubules and investigate the interaction between PVM/MA and type I collagen using surface plasmon resonance (SPR). Fifteen volunteers brushed dentin discs in situ using dentifrices with and without PVM/MA copolymer in a cross-over design. Dentin tubule occlusion was evaluated after brushing, after overnight saliva challenge in vivo for 12 h and after drinking 250 ml of orange juice. Dentin tubule occlusion and tubule size were compared between the two groups using repeated ANOVA and before and after erosive challenges using paired t tests. SPR using type I collagen as ligand and PVM/MA as analyte was performed to evaluate the binding of the two macromolecules. A median of 91% of dentin tubules were occluded after a single brushing in the PVM/MA group, as compared to 9% in the controls. After overnight saliva challenge and 10 min of erosion by orange juice, a median of 73% of the dentin tubules remained fully occluded in the PVM/MA group as compared to zero in the controls. Dentin tubule size increased after orange juice erosion in the controls but not in the PVM/MA group. SPR study showed that PVM/MA bound readily to collagen molecules in a 4 to 1 ratio. Dentifrice containing PVM/MA could effectively occlude dentin tubules and prevent dentin erosion. PVM/MA may improve adhesive retention of intra-tubular dentifrice plugs through binding to dentin surface collagen. Brushing with dentifrice containing adhesive polymers has preventive effect against dentin erosion and dentin sensitivity.