PROTECTIVE EFFECT OF EXPERIMENTAL BIOACTIVE COMPOSITES ON ENAMEL - A PILOT STUDY.

Španović, Nika; Par, Matej; Attin, Thomas; Tarle, Zrinka; Tauböck, Tobias T.

Aim: Bioactive glasses (BGs) can be used to render resin composites anti-cariogenic. This pilot study aimed to investigate the protective effect of experimental BG-composites on enamel immersed in a repeatedly replenished acidic solution. Materials and methods: Three experimental composites based on a photo-curable resin (60:40 wt% bisphenol-A-glycidyldimethacrylate and triethylene glycol dimethacrylate) and a total filler ratio of 70 wt% were prepared by replacing 0, 10, and 20 wt% of silanized reinforcing fillers (barium glass and silica) with unsilanized BG 45S5. Enamel blocks (3x3x1 mm, n=9) were prepared from intact human third molars. Light-cured composite specimens (diameter=7 mm, thickness=2 mm, n=3 per material) were immersed with enamel blocks in a lactic acid solution (5 mL, pH=4.0). The immersion medium was replenished every four days. Knoop microhardness (MH; load=100 g, dwell time=20 s; n=5 per measurement) and pH of the immersion medium were assessed at the following time points (days): 0, 4, 8, 12, 16, and 20. Statistical analysis was performed using a nonparametric one-way ANOVA on ranks (Kruskal-Wallis). Results: The enamel blocks immersed with the 0 wt%-BG composite showed a statistically significant MH decline after 4 days, whereas the MH of enamel blocks immersed with the 10 wt%-BG composite remained unchanged up to 8 days. The enamel blocks immersed with the 20 wt%-BG composite showed no statistically significant MH change throughout the whole observation period. The pH value of the immersion medium was unchanged by the 0 wt%-BG composite, for the 10 wt% BG composite a transient pH increase was observed, while the 20 wt%-BG composite showed an extensive increase up to pH=9.8, which was maintained throughout the whole observation period. Conclusions: A dose-dependent protective effect against repeated acid attacks was identified for experimental composites functionalized with 10-20 wt% of BG 45S5.

ENAMEL & enameling; BIOACTIVE glasses; FUSED silica; CARIOGENIC agents; ACID throwing; DENTAL enamel; METHACRYLATES

Acta Stomatologica Croatica, 2020, Vol 54, Issue 4, p448

0001-7019

Academic Journal