The influence of "C-factor" and light activation technique on polymerization contraction forces of resin composite

• Váldodahkkit: Sérgio Kiyoshi Ishikiriama (Dahkki), Thiago Majolo Valeretto (Dahkki), Eduardo Batista Franco (Dahkki), Rafael Francisco Lia Mondelli (Dahkki)
• Materiálatiipa: Girji
• Almmustuhtton: University of São Paulo, 2012-12-01T00:00:00Z.
• Fáttát: article
• Liŋkkat: Connect to this object online.
• Notes: 1678-7765; 10.1590/S1678-77572012000600003
• Keywords: Composite resins; Physical properties; Bis-GMA; Dentistry; RK1-715
• Source: Journal of Applied Oral Science, Vol 20, Iss 6, Pp 603-606 (2012)

OBJECTIVES: This study evaluated the influence of the cavity configuration factor ("C-Factor") and light activation technique on polymerization contraction forces of a Bis-GMA-based composite resin (Charisma, Heraeus Kulzer). MATERIAL AND METHODS: Three different pairs of steel moving bases were connected to a universal testing machine (emic DL 500): groups A and B - 2x2 mm (CF=0.33), groups C and D - 3x2 mm (CF=0.66), groups e and F - 6x2 mm (CF=1.5). After adjustment of the height between the pair of bases so that the resin had a volume of 12 mm³ in all groups, the material was inserted and polymerized by two different methods: pulse delay (100 mW/cm² for 5 s, 40 s interval, 600 mW/cm² for 20 s) and continuous pulse (600 mW/cm² for 20 s). Each configuration was light cured with both techniques. Tensions generated during polymerization were recorded by 120 s. The values were expressed in curves (Force(N) x Time(s)) and averages compared by statistical analysis (ANOVA and Tukey's test, p<0.05). RESULTS: For the 2x2 and 3x2 bases, with a reduced C-Factor, significant differences were found between the light curing methods. For 6x2 base, with high C-Factor, the light curing method did not influence the contraction forces of the composite resin. CONCLUSIONS: Pulse delay technique can determine less stress on tooth/restoration interface of adhesive restorations only when a reduced C-Factor is present.