Objectives

  This study evaluated the effect of fluoride and non-fluoride sealants on hardness decrease (HD) and marginal adaptation (MA) on enamel substrates after cariogenic challenge.

  Methods

  Occlusal enamel blocks, from human third molars, were randomly divided into six groups (n=12), according to occlusal fissures condition (S – sound C – caries-like lesion CF – caries-like lesion+topical fluoride) and sealants (F – FluroShield H – Helioseal Clear Chroma). Lesion depths were 79.3±33.9 and 61.3±23.9 for C and CF groups, respectively. Sealants were placed on occlusal surface and stored at 100% humidity (37°C 24h/d). HD was measured by cross-sectional microhardness analysis at the sealant margin distances: −1 (under sealant), 0 (sealant margin), 1, 2 (outer sealant). Sealant MA was observed by polarized light microscopy and scored according to: 0 – failure (no sealant MA or total sealant loss) 1 – success (sealant MA present). MA and HD were analysed by ANOVA-R and mixed model analysis, respectively.

  Results

  For HD (ΔS), F values (6900.5±3686.6) were significantly lower than H values (8534.6±5375.3) regardless of enamel substrates and sealant margin distances. Significant differences were observed among sealant margin distances: −1 (5934.0±3282.6)<0 (8701.5±6175.7)=1 (8473.2±4299.4)=2 (7761.5±4035.1), regardless of sealant and substrate. MA was similar for all groups (p≥0.05).

 Conclusion

  MA was not affected by sealant type or substrate condition, whereas enamel HD was favourably impacted by fluoride in the sealant. In addition, sealants were more effective as a physical barrier than as its chemical potency in reducing enamel HD.

 Clinical significance

 Sealing with a fluoride material is a recommended procedure to prevent caries of occlusal permanent molars in high-caries-risk patients, even though those exhibiting white spot lesions, since the enamel hardness decrease when fluoride sealant was used in vitro.

 Source: Journal of Dentistry

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