The influence of "C-factor" and light activation technique on polymerization contraction forces of resin composite
AUTOR(ES)
Ishikiriama, Sérgio Kiyoshi, Valeretto, Thiago Majolo, Franco, Eduardo Batista, Mondelli, Rafael Francisco Lia
FONTE
J. Appl. Oral Sci.
DATA DE PUBLICAÇÃO
2012-12
RESUMO
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.
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