INFLUENCE OF NAIL VARNISH ON THE REMINERALIZATION OF ENAMEL SINGLE SECTIONS ASSESSED BY MICRORADIOGRAPHY AND CONFOCAL LASER-SCANNING MICROSCOPY

Single-section techniques are attractive in enamel de- and remineraliz ation investigations because they allow longitudinal studies in which mineral changes can be assessed by microradiography (TMR), Nail Varnis h (NV) is in general applied to coat the cut thin-section sides, The a ims of this study were to investigate: (1) NV penetration depth in cut surfaces of demineralized enamel, (2) the influence of NV on cut surf aces of demineralized enamel on TMR, (3) the influence of NV penetrati on on a following remineralization, Cut surfaces of thin sections of d emineralized enamel were NV coated; the NV was peeled off and the pene tration depth assessed by confocal laser scanning microscopy. The NV p enetration was 18+/-5 mu m (mean+/-SD) in demineralized enamel. To eva luate the possible influence of NV on TMR, cut surfaces of thin sectio ns of demineralized enamel were coated (twice) and microradiographed b efore and after nail varnishing. The NV effect (total effect of penetr ated and surface NV) on the main parameters of TMR, Ld and Delta Z, wa s less than 5% of the mean values. In the remineralization experiment (remineralization with 1.5 mM Ca2+, 0.9 mM phosphate, pH 7, 1 ppm F fo r 1 and 2 weeks), lesions in bulk samples, lesions in thin sections wi th NV-coated cut surfaces and lesions in thin sections in a PMMA (poly methylmethacrylate) holder were compared. (1) The remineralization of bulk samples and of NV-coated thin sections is different in one aspect . The amounts of mineral deposited in the lesions expressed as Delta Z are comparable after 1 week. But because the NV penetrates part of th e lesion outside, there was an Ld difference. The lesion depth differe nce between bulk lesions and NV-coated lesions in thin sections was st atistically significant and was about 19% less in NV-coated lesions af ter 1 week; after 2 weeks of remineralization there was no difference in Ld between bulk- and NV-coated lesions any more. (2) There was no d ifference in remineralization efficacy between lesions in bulk samples and lesions in thin sections in the PMMA holder.