Efficacy of fluoride products in preventing demineralization of root surfaces

Objective: The aim of this study was to evaluate the effectiveness of commercially available, and professionally prescribed or applied fluoride agents in preventing demineralization of extracted human tooth root surfaces.   

Methods: On 121 non-carious root surfaces a 1mm X 6mm window was created and exposed to a simulated oral environment.  Each surface was randomly assigned to 1 of 5 groups: Control, 3M Cavity Shield 5% NaF Varnish (22,000ppm – applied once), Oral-B® Neutra-Foam® 2% NaF (9,000ppm – applied once), PreviDent 5000 Plus^TM (5,000ppm – applied daily), or Crest® Cavity Protection (1,100ppm – applied daily).  For 17 days, every 24 hours teeth were exposed cyclically to demineralizing solution (acetic acid  pH4.3 – 2 hours), remineralizing solution (artificial saliva - 21 hours), and daily fluoride (PreviDent and Crest) or artificial saliva (control, varnish, foam) for 1 hour.  Teeth were sectioned exposing the internal surface of the root windows. Lesion depths were measured using polarized light microscopy and Image Pro Plus computer software. Descriptive statistics, ANOVA, and pairwise comparisons were performed using SAS 9.2 and R statistical software.

Results: There were significant differences (ANOVA p<0.0001) across all groups.  The mean lesion depth was highest in the control group (144.52μm) followed by Neutra-foam (128.63μm), Varnish (120.18μm), Crest (85.37μm), and Prevident (70.67μm). Pairwise comparisons showed that all treatments were significantly different from each other after adjustment for multiple comparisons to preserve an overall Type I error of 0.05 (Tukey-Kramer adjusted p=0.0492 for 3M Cavity Shield Varnish and Neutra-Foam comparison and adjusted p<0.0001 for all other pairs).

Conclusions: In regards to demineralization prevention the daily use of fluoride pastes (Prevident and Crest) displayed the greatest amount of protection, followed by the one-time application of professionally applied fluorides (varnish and foam).  The control group with no fluoride treatment resulted in the largest carious lesions.