Micro-computed tomography evaluation of volumetric polymerization shrinkage and degree of conversion of composites cured by various light power outputs

• Published in: Dental Materials Journal Vol. 37; no. 1; pp. 33 - 39
• Main Authors: ATRIA, Pablo J., SAMPAIO, Camila S., CÁCERES, Eduardo, FERNÁNDEZ, Jessica, REIS, Andre F., GIANNINI, Marcelo, COELHO, Paulo G., HIRATA, Ronaldo
• Format: Journal Article
• Language: English
• Published: Japan The Japanese Society for Dental Materials and Devices 2018; Japanese Society for Dental Materials and Devices; Japan Science and Technology Agency
• Subjects: Composite; Composite materials; Computation; Computed tomography; Conversion; Curing; Dentistry; Fourier transforms; Infrared spectroscopy; Light-curing; Polymerization; Restoration; Shrinkage; Variance analysis; Polymerization; Light-curing; Shrinkage; Composite; Computed-tomography
• ISSN: 0287-4547; 1881-1361
• DOI: 10.4012/dmj.2016-430

This study evaluated the influence of different light-curing modes on the volumetric polymerization shrinkage and degree of conversion of a composite resin at different locations using micro-computed tomography and Fourier transform infrared spectroscopy (FTIR). Specimens were divided into 4 groups based on the light-curing mode used (Bluephase 20i): 1 —High (1,200 mW/cm2); 2 —Low (650 mW/cm2); 3 —Soft-start (650–1,200 mW/cm2); and 4 —Turbo (2,000 mW/cm2). Degree of conversion was calculated by the measurement of the peak absorbance height of the uncured and cured materials at the specific wavenumbers, and was performed by FTIR 48 h after curing resin samples. Degree of conversion was analyzed using two-way ANOVA. No significant differences were observed independent of the region of the restoration investigated (p>0.05). Different curing modes did not influence volumetric shrinkage neither degree of conversion of class I composite resin restorations.