Enamel remineralization by fluoride-releasing materials: proposal of a pH-cycling model

ABSTRACT

This study proposes a pH-cycling model for verifying the dose-response relationship in fluoride-releasing materials on remineralization in vitro. Sixty bovine enamel blocks were selected for the surface microhardness test (SMH1). Artificial caries lesions were induced and surface microhardness test (SMH2) was performed. Forty-eight specimens were prepared with Z 100, Fluroshield, Vitremer and Vitremer » diluted - powder/liquid, and subjected to a pH-cycling model to promote remineralization. After pH-cycling, final surface microhardness (SMH3) was assessed to calculate percent recovery of surface microhardness ( percentSMHR). Fluoride present in enamel (μg F/mm3) and in the pH-cycling solutions (μg F) was measured. Cross-sectional microhardness was used to calculate mineral content (∆Z). There was no significant difference between Z 100 and control groups on analysis performed on - percentSMHR, ∆Z, μg F and mg F/mm3 (p>0.05). Results showed a positive correlation between percentSMHR and μg F/mm3 (r=0.9770; p=0.004), percentSMHR and μg F (r=0.9939; p=0.0000001), ∆ and μg F/mm3 (r=0.9853; p=0.0002), ∆ and μg F (r=0.9975; p=0.0000001) and between μg F/mm3 and μg F (r=0.9819; p=0.001). The pH-cycling model proposed was able to verify in vitro dose-response relationship of fluoride-releasing materials on remineralization.

RESUMO

Este trabalho propôs um modelo de ciclagem de pH verificando a relação dose-resposta de materiais que liberam flúor na remineralização in vitro. Foram selecionados 60 blocos de esmalte bovino pelo teste de microdureza de superfície (SMH1). Realizou-se indução de cárie e microdureza de superfície pós-cárie (SMH2). Corpos-de-prova (n=48) dos grupos Z 100, Fluroshield, Vitremer e Vitremer diluído » foram fabricados e submetidos à ciclagem de pH para promover a remineralização. Após, avaliou-se a microdureza de superfície final (SMH3) para cálculo da porcentagem de recuperação da microdureza de superfície ( por centoSMHR). Determinou-se o flúor presente no esmalte (μg F/mm3) e nas soluções de ciclagem (μg F). O teste de microdureza em secção longitudinal foi realizado para cálculo do conteúdo mineral (∆Z). Entre os grupos controle e Z100 não houve diferença significativa nas análises realizadas - por centoSMHR, ∆Z, μg F e μg F/mm3 (p>0,05). Houve correlação positiva entre a por centoSMHR e μg F/mm3 (r=0,9770; p=0,004), por centoSMHR e μg F (r=0,9939; p=0,0000001), ∆Z e μg F/mm3 (r=0,9853; p=0,0002), ∆Z e μg F (r=0,9975; p=0,0000001) e também entre μg F/mm3 e μg F (r=0,9819; p=0,001). O modelo de ciclagem de pH proposto foi adequado para verificar relação dose-resposta in vitro de materiais que liberam flúor na remineralização.