Secondary caries prevention using silver-diamine-fluoride treatment and CPP-ACP-modified glass-ionomer cement

Abstract

Objectives: To study the effect of silver diamine fluoride (SDF) treatment and incorporating casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) into a glass-ionomer cement (GIC) to prevent secondary root caries. Methods: Thirty-two sound human premolars were collected. A cervical cavity was prepared on each premolar for the following restoration groups: group 1, conventional GIC restoration; group 2, SDF (38%) treatment and conventional GIC restoration; group 3, CPP-ACP (3%) modified GIC; and group 4, SDF treatment and CPP-ACP modified GIC. The restored teeth were thermal-cycled before undergoing a cariogenic biofilm challenge using a consortium of Streptococcus mutans, Streptococcus sobrinus, Actinomyces naselundii and Lactobacillus rhamnosus anaerobically for 7 days. The response of the restored teeth to the cariogenic challenge were examined by micro-computed tomography (micro-CT), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) and Fourier transform infrared (FTIR) spectroscopy. Data were analyzed by two-way ANOVA. Results: Micro-CT determined outer lesion depths for groups 1-4 were: 123±6 µm, 87±7 µm, 79±3 µm and 68±5 µm respectively. An interaction effect on the outer lesion depth was found between the restorative materials and SDF treatment (p<0.001). Both SDF treatment and modification with CPP-ACP had a significant effect on outer lesion depth (p<0.001). SEM/EDX showed an increase of calcium and phosphorus at the root dentine adjacent to the restoration in groups 3 and 4 (CPP-ACP modified GIC). FTIR determined that the mean values (±SD) of amide I: HPO42- of dentine in groups 1 to 4 were 0.69±0.06, 0.49±0.05, 0.47±0.05 and 0.39±0.04 respectively (p=0.001). Hence, SDF treatment and CPP-ACP modified GIC had a significant inhibition of demineralization on the material-root interface. Conclusions: SDF treatment and incorporation of CPP-ACP into GIC restorative material can prevent secondary root dentine caries development. The results provide useful information to dentists in formulating clinical management protocols and material when treating root caries.