Effect of desensitizing toothpastes on dentin erosive wear and tubule occlusion. An in situ study.

PURPOSE: To evaluate the effect of desensitizing dentifrices on dentin wear and tubule occlusion using a three-phase, single blind, crossover in situ trial.

METHODS: The dentifrices containing Arginine and calcium carbonate (1,450 ppmF) and Novamin, (~1,426 ppmF) were tested in two conditions: A: abrasion and B: erosion/abrasion. A dentifrice without desensitizing agents was used as control (1,450 ppmF). In each study phase, 10 volunteers used intra-oral appliances containing dentin specimens (pre-treated with EDTA, to simulate hypersensitive dentin), which were either submitted to erosion with a cola-like drink (pH 2.6), 4×/day (2 minutes), followed by toothbrushing, using electric toothbrushes, with standard pressure (2×/ day, 5 seconds), or toothbrushing only. Dentin surface loss (SL, in µm) was determined with optical profilometry at the 3rd and 5th days of cycling. Dentin surface was analyzed with environmental scanning electron microscopy (ESEM), post EDTA and post cycling, and the dentin tubules were counted using Image J software. Data were statistically analyzed (α= 0.05).

RESULTS: For condition A and B, there were no significant differences in SL among toothpastes in both experimental times. There were also no significant differences between times within groups. For ESEM, in A, Toothpaste with Novamin was the only dentifrice that showed significantly less opened tubules post cycling than post EDTA. In B, Toothpaste with Novamin and control toothpaste presented less opened tubules post cycling. In conclusion, toothbrushing with the tested dentifrices promoted similar levels of dentin loss; however, for tubule occlusion, the toothpaste with Novamin was the only toothpaste effective for both conditions, abrasion and erosion/abrasion.

CLINICAL SIGNIFICANCE: Ideally, desensitizing dentifrices should promote obliteration of the dentin tubules or nerve desensitization, without further contributing to the progression of dentin wear.