In situ randomised trial investigating abrasive effects of two desensitising toothpastes on dentine with acidic challenge prior to brushing.

Objectives: To determine if brushing dentine with 2 moderate RDA desensitising toothpastes, results in a significant dentine wear difference and whether this difference continues to be relevant when preceded with an erosive challenge.

Methods: An in situ, single centre, single blind, randomised, split mouth study, evaluated the difference in abrasion of 2 toothpastes (SFM - Sensodyne Fresh Mint(®) RDA 70; CPHM - Crest Pro-Health Clean Mint(®) RDA 120) in 28 healthy volunteers. Two toothpaste treatments were administered 3×/day, for each of the two 15 day periods, subjects wearing bi-lateral, lower buccal appliances each with 4 dentine sections. A 2 min extra-oral acidic challenge preceded toothbrushing for 2 study arms. Contact profilometry measured samples at baseline, days 5, 10 and 15.

Results: Brushing with SFM was significantly less abrasive than brushing with CPHM at all time points, with or without a preceding acidic challenge (p<0.0001). The additional dentine loss arising from the erosive challenge prior to brushing with each paste was linear with time and independent of abrasive effect.

Conclusions: The desensiting toothpastes' RDA, directly related to dentine loss with toothbrushing. An acidic challenge prior to brushing did not negate the benefits of reduced wear from the lower RDA paste compared to the higher RDA paste. When brushing eroded dentine, the additional wear appeared independent of abrasive effect. Dentine hypersensitivity sufferers should be recommended to use a low-moderate RDA toothpaste, not to brush more than 2×/day and not immediately following an acidic challenge.