Efficient enamel subsurface lesion remineralisation and dentine tubule occlusion by high concentration CPP-ACP: a randomised, cross-over in situ study

Abstract

This study assessed the efficacy of 60% CPP-ACP to remineralise white spot lesions (WSLs) in enamel and to occlude patent dentinal tubules in a double-blind, randomized, cross-over, in situ study. Human enamel specimens with subsurface lesions (WSLs) and root dentine specimens with open dentinal tubules were prepared and inserted into intra-oral appliances worn by volunteers. Participants wore the appliances 24 h a day for four 14-consecutive day treatment periods with a 7-day washout period between treatments. Four treatments applied with a micro-brush once daily were 60% CPP-ACP with and without 1100ppm F as SnF₂, 1100ppm F as SnF₂ alone and a placebo as negative control. Mineral content was measured using transverse microradiography and dentine tubules were examined using scanning electron microscopy (SEM). The data were analysed using a repeated measures ANOVA with a Sidak adjustment for multiple comparisons. Once daily application of 60% CPP-ACP with or without SnF₂ produced 36.6 ± 1.6% and 28.8 ± 1.5% remineralisation of the WSLs respectively, and both were significantly higher (p < 0.0001) than that for treatment by SnF₂ alone (8.8 ± 0.7%) or placebo control (2.3 ± 0.4%). SEM analysis of the dentine samples showed that daily application of 60% CPP-ACP with or without SnF₂ produced near complete dentinal tubule occlusion.

Keywords: Casein phosphopeptide-amorphous calcium phosphate; Enamel; Fluoride; Remineralisation; Stannous.

Fig. 1

Treatment of white spot lesions with a 60% CPP-ACP formulation. (A) White spot lesions (WSLs) caused by plaque accumulation around orthodontic brackets and (B) demineralisation of the underlying enamel shown on debanding and removal of the brackets. (C) Simulation of white spot lesions on human tooth enamel in vitro with the enamel block containing the WSLs cut in half and one half (left side) painted with 60% CPP-ACP using a microbrush.

Fig. 2

Representative microradiographs showing remineralisation of enamel subsurface lesions by Placebo, SnF_2, CPP-ACP, or CPP-ACP/SnF₂.

Fig. 3

SEM images of dental tubule occlusions after daily application of 60% CPP-ACP formulations with and without SnF₂ compared with SnF₂ and placebo control. Images of representative regions were captured at 3000x magnification with a FEI ESEM Quanta 600 FEG in low vacuum mode using a solid-state backscattered electron detector at 10 kV, spot size 4.0.

Fig. 4

Participant disposition of the cross-over clinical trial. A = 60%CPP-ACP/SnF₂, B = 60%CPP-ACP, C = SnF₂, D = Placebo.

Fig. 5

Clinical phases of this in situ study.

Fig. 6

A schematic representation of the in situ study appliances processes.