Toothpaste Diluent and Dilution Rate Effects on Dentin Abrasion

Objectives: This study was undertaken to determine whether toothpaste diluent type and dilution rate influence abrasion of dentin. Methods: One hundred and sixty-five human root dentin slabs (4x3mm) were embedded in epoxy resin and prepared to 1200-grit Al₂O₃ and 3-µm alumina finish. Adhesive tape was placed on specimen's surface leaving an exposed central area of 2x3mm. Specimens were then brushed for 10,000 strokes in a reciprocal action brushing simulator using a toothpaste (Crest, RDA=100) that had been diluted in a carboxymethylcellulose-based artificial saliva (CMC) or deionized water (DW) from 1:1 to 1:4 (toothpaste:diluents, w:w). Control groups were brushed with undiluted toothpaste (UND), CMC-based saliva and DW only. Brushing simulation was run at 300 g load at 37 ^oC. After brushing, adhesive tapes were removed and wear analyzed by optical profilometry. Results: One-way Anova (p<0.0001) and Tukey's test revealed that wear depth (µm) declined with increasing dilution, regardless of the diluent. Neat toothpaste generated the highest wear, whereas brushing with CMC- and DW-only caused the least abrasion.

Supported by GlaxoSmithKline.