SECONDARY CARIES IN DENTIN AROUND COMPOSITES - A WAVELENGTH-INDEPENDENT MICRORADIOGRAPHICAL STUDY

Composite restorations are prone to develop secondary caries if a gap exists between tissue and restoration. The aim of this article was to quantify the effects of a fluoridating and non-F composite on secondar y dentine caries in vitro as a function of time. The mineral loss in d entine was assessed in an artificial gap of 200 mu m width at the comp osite/dentine interface; the samples were demineralised in a carboxyme thylcellulose gel (pH = 5, 37 degrees C) for 8 weeks. Once a week the mineral content of the samples was determined using non-destructive wa velength-independent microradiography (WIM). After 8 weeks transversal microradiography (TMR) was done on the samples to investigate the min eral distribution of the dentine lesions. The WIM results show that th e fluoride-releasing composite decreased the dentine demineralisation statistically significantly with respect of the non-F control by appro ximately 45%. The mineral loss values are found to be strictly proport ional to time; the demineralisation reduction is expected to continue over extended periods of clinical relevance. The TMR results show that the fluoridating composite reduced the mineral loss values significan tly with respect to the non-F control by approximately 55%, but had a negligible effect on the lesion depth values. This study indicates tha t WIM is an accurate and reliable technique to measure in vitro second ary dentine caries next to a composite restoration as a function of ti me.