Approximal caries development in surfaces in contact with fluoride-releasing and non-fluoride-releasing restorative materials: an in situ study.

This study investigated the effect of compomer on initial interproximal caries development. One-hundred and sixty cylindrical, and 40 semispherical, bovine enamel samples (control) were prepared, polished, and sterilized. Sixty semicircular samples were prepared from each of the compomer Dyract eXtra and the fluoride-free composite Spectrum TPH. Samples were stored in water and fluoridated twice daily for 28 d. A baseline quantitative light fluorescence (QLF) image was made of each cylindrical sample. Twenty volunteers received intra-oral appliances with eight sample chambers. Each wing contained 1 control sample and either 3 Dyract eXtra or 3 Spectrum TPH samples in contact with the enamel surface of a cylindrical enamel sample. Appliances were worn for 24 h a day for 28 d except during toothbrushing (twice daily) and placement in 10% sucrose solution (five times daily). A final QLF image was made after 28 d. Caries development was analyzed as the lesion area x mean fluorescence loss (DeltaQ % mm(2)) between these and the baseline images using QLF subtract software. The median DeltaQ was significantly lower in the Dyract eXtra group (-6.1% mm(2)) than in the Spectrum TPH (-13.9% mm(2), P <or= 0.001) or control (-11.4% mm(2), P=0.03) groups. Teeth in contact with the compomer developed less caries compared with controls.