Saliva substitute in combination with high-concentrated fluoride toothpaste: effects on demineralised dentin in vitro

The aim of this in vitro study was to assess the effects of saliva substitutes (modified with respect to calcium, phosphates, and fluorides) in combination with a high-concentrated fluoride toothpaste on demineralised dentin.

Before and after demineralisation of bovine dentin specimens (subsurface lesions; 37 degrees C, pH 5.0, 5 d), one-quarter of each specimen's surface was covered with nail varnish (control of sound/demineralised tissue). Subsequently, specimens were exposed to original Saliva natura (saturation with respect to octacalciumphosphate [S(OCP)]: 0.03; SN 0), or to three lab-produced Saliva natura modifications (S(OCP): 1, 2, and 3; SN 1-3) for 2 and 5 weeks (37 degrees C). An aqueous solution (S(OCP): 2.5) served as positive control (PC). Two times daily (2min each), Duraphat toothpaste (5000ppmF(-); Colgate)/saliva substitute slurry (ratio 1:3) was applied gently. Differences in mineral losses (DeltaDeltaZ) and lesion depths (DeltaLD) between values before and after exposure were microradiographically evaluated.

After both treatment periods specimens immersed in SN 0 revealed significantly higher mineral losses (lower DeltaDeltaZ values) and lesion depths (lower DeltaLD) compared to PC (p<0.05; ANOVA). After 5 weeks, specimens stored in SN 1 and 2 showed significantly higher mineral losses compared to PC (p<0.05), while those stored in SN 3 showed similar results (p>0.05). No differences in mineral loss could be observed between SN 2 and 3 (p>0.05).

Under the conditions of this limited protocol, the combination of Saliva natura solutions slightly saturated with respect to OCP in combination with a high-concentrated fluoride toothpaste enabled remineralisation of dentin in vitro.