: In situ investigation of dentine tubule occlusion

Objectives: To investigate in situ dentine tubule occlusion by 4 toothpastes using dentine replication. Methods: This exploratory in situ study utilised a single blind, 4-day, 4-cell, split-mouth crossover design. Subjects wore 2 removable lower buccal appliances each holding four human dentine slabs. The pastes were: A. Marketed occluding desensitising product; B and C. Experimental occluding pastes; D. Marketed non-occluding desensitising product. Each group of 4 dentine slabs underwent twice daily brushing, performed ex vivo, with one of the study pastes. One dentine slab was removed from each side of the appliance at daily intervals. Tubule occlusion was scored using a visual 5-point categorical scale (1=Complete occlusion to 5=No occlusion) from scanning electron micrographs of dentine surface replicas. Mean occlusion classification scores (MOC) from 4 independent examiners were analysed by an ANOVA, which if significant, with appropriate paired comparisons. Results: At day 4, MOC (SD) for A=1.3(0.54), B=4.1 (0.70), C=2.8 (1.62) and D=3.2 (1.48). Analyses revealed significantly more occlusion with A compared to all other pastes. C produced significantly more occlusion than B. No other treatment differences reached significance. Conclusions: This in situ method combined with SEM replica analysis was shown to successfully differentiate between a recognised occluding anti-sensitivity toothpaste and non-occluding control. The experimental occluding pastes could not be shown more effective than the non-occluding paste in this model.