Evaluation of flexural strength and shear bond strength of repaired microhybrid composite with varied surface treatments

摘要: The aim of this study was to evaluate the effect three different surface treatments on flexural strength (FS) and shear bond (SBS) repaired microhybrid composite. For FS test composite specimens (n  = 36: 2 mm ´ 2 mm ´ 12.5 mm) used for repair were shaped in a silicone mould. SBS (n = 36: diameter =  8 mm, thickness = 3 mm) metal mould, cured visible light, embedded dental stone. Three methods preparation evaluated: group A (control) treated by etching with 35 % phosphoric acid, B air abraded 50 μm aluminium oxide at 100 psi C received two parallel 1 mm deep grooves using 1/4 round burr before being acid. After treatment bonding agent placed each specimen light-cured. Repairs accomplished adding more or specimens. Specimens thermocycled 500 times between 5 °C 55 °C 30 s dwell times. All tested loading failure rate 0.5 mm/min an Instron universal testing machine. Statistical analysis done ANOVA compare means within tests Tukey post hoc (p < 0.05) detect any differences. Mean values (MPa) were: A = 60.5 ± 9.9, B = 73.9 ± 13.2 C = 81.3± 14.3. A = 24.5 ± 4.4, B = 28.5 ± 4.3 C = 27.0 ± 2.8. FSs groups significantly greater than but there no significant difference B. differences Acid alone not very effective producing well-bonded repairs. Mechanical retention acid as air-abrasion Either mechanical abrasion is recommended prior repairing existing restoration achieve highest strength.