1046 Roughness and microhardness of a silorane-based composite resin

Friday, March 23, 2012: 3:30 p.m. - 4:45 p.m.
Presentation Type: Poster Session
G.R. BASSO1, V.C. RUSCHEL1, H.P. MAIA1, and M.A.C. DE ANDRADA2, 1Odontologia - Disciplina de Dentística, Universidade Federal De Santa Catarina, Florianópolis, Brazil, 2Odontologia - Disciplina de Dentística, Universidade Federal De Sant Caterina, Florianópolis, Brazil
Objective: To evaluate the effect of different polishing systems on the surface roughness and microhardness of a silorane-based composite resin.

Method: Fourty disks (12 mm diameter and 2.5mm thickness) were fabricated using a low-shrinkage composite resin (Filtek P90, 3M/ESPE) with the aid of a metallic matrix. A mylar strip and a glass slab were placed on the specimens before light-activation. The disks were divided in four groups (n=10) according to the polishing system: G1 – Mylar strip (control); G2 – Felt disks and diamond pastes; G3 – coarse-, medium-, and fine-grain finishing disks; G4 – polishing diamond points. The specimens were stored in distilled water at 37oC for 24 hours. Surface roughness (Ra) of ten specimens was measured using a handheld digital rugosimeter (RP-100, Instrutherm). Three consecutive measurements were taken in different directions in each specimen. Vickers microhardness test was performed by making three indentations in different regions of each specimen. Specimens’ mean individual values for both tests were subjected to statistical analysis one-way ANOVA and Ryan-Einot-Gabriel-Welsch test (p≤0,05). 

Result: Regarding the surface roughness, the values of G2 and G3 were significantly greater than those found for G4 (p<0.05), and no other differences were found between other groups. Conversely, G2 was found to have the greatest values, but it was not signficantly different from G4. There were no statistically signficantly differences between all groups for Vickers hardness test.

Conclusion: Polishing methods changed the surface roughness of silorane-based composites, but did not affect the microhardness values.

Keywords: Composites, Dental materials and microhardness