engleski

Degree of conversion of experimental composite materials based on amorphous calcium phosphate

Aim: To assess the degree of conversion (DC) of experimental composite materials based on amorphous calcium phosphate (ACP) in relation to curing depth and duration. Materials and methods: Light-curing experimental composite materials were prepared by blending methacrylate resin (67% Bis-EMA, 23% TEGDMA, 10% HEMA) with ACP, barium glass (Ba) and silica (Si) fillers using a dual asymmetric centrifugal mixer. Three ACP-based materials and one control material based on conventional silanized fillers were prepared (numbers in abbreviations refer to the mass ratio of a certain component): ACP40, ACP40-Ba5Si5, ACP40-Ba9Si1 and Ba40Si10. Cylindrical samples with a 3 mm diameter and a 4 mm height (n = 5) were light cured with irradiance of 1090 mW/cm2, for 20 or 40 seconds. DC was determined with Raman spectroscopy. Statistical analysis was performed using mixed model ANOVA. Results: Surface DC values (%) amounted to (20s/40s): ACP40 86.4/85.3 ; ACP40-Ba- 5Si5 80.3/80.6 ; ACP40Ba9-Si1 79.5/79.6 ; Ba40Si10 33.4/38.7. Among the listed values, only these for Ba40Si10 differed significantly. At clinically relevant curing depths (up to 2 mm), all of the ACP materials attained significantly higher DC than Ba40Si10, regardless of the curing duration. DC values of ACP40-Ba5Si5 and ACP40-Ba9Si1 up to 2 mm (83.0-62.3%) were significantly lower than that of ACP40 (88.0-75.7%). Conclusion: All of the experimental ACP-based composites attained very high DC at depths up to 2 mm. Although the addition of barium glass and silica decreased the DC, the obtained values were still above the range of commercial composites. The study was supported by CSF programme (08/31).

degree of conversion, remineralizing composites

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