Microradiography and confocal laser scanning microscopy applied to enamel lesions formed in vivo with and without fluoride varnish treatment

The aim of the present investigation was to combine 2 techniques suitable for lesion characterization: quantitative microradiography (TMR) and confocal laser scanning microscopy (CLSM) on in vivo induced lesions with and without a fluoride varnish (Duraphat(R)) treatment. Orthodontic bands were attached to premolars to be extracted for orthodontic reasons to induce enamel caries on the buccal surfaces. In the caries development part of the study, 1 tooth of each pair received at the start 1 topical application with the fluoride varnish Duraphat(R), the contralateral tooth serving as untreated control. All teeth were extracted after 4 weeks. In the caries progression part, the premolars were banded for 4 weeks without any treatment to induce caries. 1 premolar in each pair was then extracted and analyzed, The contralateral tooth received one Duraphat(R) application and was extracted after another 2 weeks. In the caries development part of the study, TMR analysis showed that the Duraphat(R) treatment on sound enamel reduced lesion depth by 48% compared to the untreated control. In the caries progression part, no significant difference was found between the untreated teeth extracted after 4 weeks and the fluoride treated lesions extracted after another 2 weeks, CLSM images agreed well with the TMR measurements. In the fluoride treated lesions, the CLSM images showed more light scattering indicating precipitation of material.