Improved Healing of White Spot Lesions In Vitro

OBJECTIVE: To assess the potential of a NovaMin®-containing (calcium sodium phosphosilicate) fluoride dentifrice to remineralize enamel white spot lesions (WSL) in vitro.

METHODS: Bovine tooth crowns were epoxy-mounted, ground, and polished expose the sound enamel layer. Surfaces were taped to leave only 5x5mm windows exposed. Artificial WSL were pre-formed on the enamel samples via immersion for 48 hours in demineralization solution (pH=4.52) at 37°C. The remaining samples were subjected to a 10-day remin/demin cycle that consisted of twice-daily 30-minute soaks in demineralization solution (pH=4.52, 37°C) followed by five-minute dentifrice treatments (dentifrice placed on lesion, 0.50mL DI water placed on dentifrice, undisturbed for 5 minutes, rinsed with DI water to remove all visible dentifrice). Samples were soaked in artificial saliva (pH=7.00, 37°C) between the two daily demineralization/treatment periods. Treatment groups were: A) Sound Enamel (grinding/polishing only), B) Lesion-only (48-hour lesion formation), C) MI Paste Plus™ (Recaldent™+900ppmF), D) Prevident® 5000 (5000ppmF), E) ReNew™ (5% NovaMin®+5000ppmF). Surface microhardness (Knoop, HK) was measured on all samples using a load of 50-100 grams for 20 seconds.

RESULTS: Data were analyzed using ANOVA on Ranks and Student-Newman-Keuls statistical methods (p<0.01). All HK data are presented as mean±S.E.M. with n=18. Results were: A) 119.39±6.78, B) 5.17±0.35, C) 6.53±0.70, D) 14.40±1.30, and E) 33.52±4.96 with A > E > D > B = C (p<0.01). Treatment with a NovaMin®-containing prescription fluoride dentifrice improved hardening of WSL compared to fluoride-only dentifrice. In this model, treatment with a Recaldent™-containing fluoride dentifrice had no hardening effect on WSL.

CONCLUSION: This in vitro model was validated by the ability of a prescription-level fluoride dentifrice to harden surfaces of enamel white spot lesions. Preliminary data also indicate that NovaMin®-containing fluoride dentifrices have greater potential to remineralize and heal white spot lesions than fluoride-only dentifrices. Results will need to be confirmed and explored clinically.