Open AccessThermal Stability and Monomer Elution of Bulk Fill Composite Resins Cured from Different Irradiation Distances
Author(s) -
Elmira Jafari Navimipour,
Fatemeh Pournaghi Azar,
Sajjad Keshipour,
Saba Nadervand
Publication year - 2021
Publication title -
frontiers in dentistry
Language(s) - English
Resource type - Journals
ISSN - 2676-296X
DOI - 10.18502/fid.v18i9.6102
Subject(s) - thermal stability , irradiation , elution , composite number , monomer , materials science , composite material , thermal , chemistry , chromatography , polymer , organic chemistry , thermodynamics , physics , nuclear physics
Objectives: This study aimed to evaluate the thermal stability and monomer elution of bulk fill composite resins cured at different irradiation distances.
Materials and Methods: Forty cylindrical-shaped (3×4mm) specimens were fabricated from two composite resins (X-tra fil, X-tra base) and cured from 0 and 7mm distances. In 9 specimens, the degree of conversion was determined by the release of monomers. For this purpose, after curing of composites, they were immersed in 5 mL of 99.9% methanol and stored at 37°C for 24h. The eluted monomer was then analyzed by gas chromatography (GC). Also, thermal stability of one sample from each group was assessed by thermogravimetric analysis (TGA) at a rate of 10°C/min. Data were analyzed using two-way ANOVA and Tukey’s post-hoc test (P<0.05).
Results: X-tra fil had significantly higher degree of conversion than X-tra base (P=0.001). Specimens cured at 7mm distance had significantly lower degree of conversion compared with those cured at 0 mm distance (P=0.001). The interaction effect of composite type and distance of light curing unit from the surface of samples was statistically significant (P=0.001). Regarding the TGA results, the lowest and the highest percentages of weight loss were detected in X-tra fil cured at 0 mm distance and X-tra base cured at 7mm distance, respectively.
Conclusion: X-tra fil composite cured at 0mm distance had the highest degree of conversion and thermal stability, and X-tra base composite cured at 7mm distance had the lowest values.