Resumo

PORTERO, PRISCILA PAIVA et al. Effect of light-curing units and glass fiber reinforcement on flexural strength of direct and laboratory-processed composites. RPG, Rev. pós-grad. [online]. 2010, vol.17, n.1, pp. 25-30. ISSN 0104-5695.

The aim of this study was to evaluate in vitro the flexural strength of direct composite resin (Z-250 FiltekTM - 3M/ESPE) and second-generation laboratory composite (II CeseaDST - Kuraray) associated or not with glass fibers (Fibrex-coronal - Angelus), changing the curing light source (L.E.Demetron 1 - Kerr and Strobolux - EDG). Fifty-six specimens of the composites F and C were constructed using a stainless-steel split ring molds and divided into eight groups: GI - Composite Z-250/ No fiber/LED; GII - Composite Z-250/No fiber/Strobolux (STR); GIII - Composite Z-250/Fibrex-coronal (FBC)/LED; GIV - Composite Z-250/FBC/STR; GV - Composite CeseaDST II/No fiber/LED; GVI - Composite CeseaDST II /No fiber/STR; GVII - Composite CeseaDST II/FBC/ LED; GVIII - Composite CeseaDST II/FBC/STR. The specimens were subjected to the flexural strength in a universal testing machine equipped with a cell load of 500Kgf at a crosshead speed of 1±0.5 mm/min. The data were submitted to Tukey's Test (p = 0.01). The mean of flexural strength was in MPa: GI - 187,91 ± 32,78; GII - 196,76 ± 31,15; GIII - 208,27 ± 18,79; GIV - 218,02 ± 15,76; GV - 101,72 ± 11,25; GVI - 103,05 ± 9,56; GVII - 164,76 ± 12,54 e GVIII - 176,75 ± 47,03. The direct composite showed the highest flexural strength values in all groups; the light source did not affect the flexural strength of the composites; fiber reinforcement increased the flexural strength of both composites; however this increase was statistically significant only for the laboratory-processed composite.

Palavras-chave : Curing lights, dental.; Flexural strength.; Composite resins..