Polymerization Kinetics of Pre-heated Composite

• Published in: Journal of dental research Vol. 85; no. 1; pp. 38 - 43
• Main Authors: Daronch, M., Rueggeberg, F.A., De Goes, M.F., Giudici, R.
• Format: Journal Article
• Language: English
• Published: United States SAGE Publications 01-01-2006; SAGE PUBLICATIONS, INC
• Subjects: Composite Resins - chemistry; Composite Resins - radiation effects; Dental Materials - chemistry; Dental Materials - radiation effects; Dentistry; Hot Temperature; Humans; Kinetics; Light; Lighting - instrumentation; Materials Testing; Polymers - chemistry; Spectrophotometry, Infrared; Surface Properties; Temperature; Time Factors; polymerization rate; curing temperature; kinetics; resin composite; monomer conversion
• ISSN: 0022-0345; 1544-0591
• DOI: 10.1177/154405910608500106

Temperature affects the polymerization behavior of dimethacrylate-based materials. This study describes the influence of pre-polymerization temperature and exposure duration on polymerization kinetics of a commercial dental photo-activated composite at the top and at 2-mm depth. We used the temperature-controlled stage of a diamond-attenuated-total-reflectance unit to pre-set composite temperature between 3° and 60°C. Composite was light-exposed by a conventional quartz-tungsten-halogen curing unit for 5, 10, 20, or 40 sec. Real-time conversion, maximum conversion rate (R
p
max), time to achieve R
p
max, and conversion at R
p
max were calculated from infrared spectra. Composite pre-warming enhanced maximal polymerization rate and overall monomer conversion (top significantly greater than 2 mm). Time when R
p
max occurred did not change with temperature, but occurred sooner at the top than at 2-mm depth. Conversion at R
p
max increased with temperature, allowing more of the reaction to occur prior to vitrification than at room temperature.