engleski

Hybrid Composite Resins Based on Amorphous Calcium Phosphate

Objectives: Remineralizing composite resins based on amorphous calcium phosphate (ACP) were modified by adding inert fillers to improve their mechanical properties. The purpose of this study was to determine if this compositional change has the influence on the degree of conversion (DC) and Vickers microhardness (HV). Methods: One control (CerX ; CeramX, Dentsply Caulk, Germany) and three ACP based composite resins: without added fillers (0-ACP), with added 10wt% of barium-glass fillers (Ba-ACP) and with 10wt% of silica fillers (Si-ACP) were tested. The samples were polymerized for 30sec by LED curing unit (1150mW/cm2 ; Bluephase G2, Ivoclar Vivadent, Liechtenstein). Fourier transform infrared spectroscopy (FTIR) was used to determine the structure of ACP and the DC, 20min and 72h after polymerization. DC (n=10) was calculated from the molar ratios of aliphatic and aromatic peaks of cured and uncured composite samples. HV (n=10) was measured with the load of 5 or 10g. Micromorphology of composite samples was visualized by scanning electron microscope. The results were analyzed by Mann-Whitney-test, ANOVA and Tukey’s post hoc test (p<0.05). Results: FTIR spectra revealed the amorphous structure of ACP. The addition of barium fillers did not reduce the DC (76.73%) and exhibited high post-cure increase of DC. Si-ACP (72.32%) had significantly lower DC than 0-ACP (75.28%). CerX had the lowest DC (56.76%), but the highest HV (20.73). Si-ACP had significantly higher HV (12.82) than 0-ACP (10.54) and Ba-ACP (10.75). Conclusions: Lower DC of Si-ACP was attributed to the polymerization-induced phase separation of matrix. Despite the lower DC, Si-ACP demonstrated higher HV, probably due to more intimate contact of nano-filler particles and resin matrix in comparison to the barium micro-fillers. Careful selection of inert fillers to be added into ACP composite’s composition can improve its properties. This study was supported by MZOS (065-0352851-0410, 035-0352851-2854, 098-0982904-2952), CSF, Forschungsgemeinschaft Dental and NIDCR (DE13169).

Composites; Hardness; Polymerization; Remineralization

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