Fluoride-releasing core build-up materials and artificial caries

This study examined the effect of fluoride-releasing core build-up materials upon both enamel and root demineralization in an artificial caries system. Thirty extracted human molars were randomly assigned to three treatment groups consisting of (1) conventional composite core build-up paste, (2) fluoridated core build-up paste and (3) glass cermet. Teeth were thermocycled 350 times between 5 degrees C and 55 degrees C using 30-second dwell times. Acid-resistant varnish was placed on the specimens to within 1 mm of the restoration and the teeth were subjected to an artificial-caries challenge at pH 4.2 for 72 hours. Teeth were then sectioned and the thin sections photographed using a polarized light microscope. Areas of the artificial-caries lesions were measured using a sonic digitizing pad. Mean lesion area (in arbitrary units from the digitizing pad) on enamel for Group 1 was 3.76 +/- 0.54; Group 2 was 2.53 +/- 1.17 and Group 3 was 2.32 +/- 0.68. Mean lesion area on root for Group 1 was 3.04 +/- 0.54; Group 2 was 2.34 +/- 0.58 and Group 3 was 2.51 +/- 0.53. ANOVA with Duncan's multiple range test of contrast indicates a significant difference (P less than 0.001) on both enamel (35 +/- 3%) and root (20 +/- 3%) between the non-fluoridated product and the two fluoridated products. There were no significant differences between Group 2 and 3.This artificial caries study indicates that a fluoride-releasing core material may be of value in preventing demineralization of tooth structure adjacent to the restorative core material.