Objective To investigate the influence of different porcelain surface treatment methods on the shear bond strength of metal brackets bonded to porcelain.Methods 80 porcelain facetswere divided randomly intotwo groups accordingto different adhesive material thatwas used to bond metal brackets. Adhesive materialwere Jing-Jin enamel adhesive and light-cured composite resin. Each group was further divided into 4 subgroups according to different surface treatment methods,which were acid etching with 37% phosphoric acid(H3PO4),acid etching with 9·6% hydrofluoric acid(HF),deglazing by grinding and silanating the porcelain surface.All specimenswere stored in 37℃waterfor24 hours and then the shear bond strength and the porcelain fracture after debonding was determined. The porcelain surfaces afterHF etching, H3PO4etching and deglazing by grindingwere examined by scanning electron microscopy respectively.Results The shear bond strengths in the HF etching groups, the deglazing groups and the silanating groups were much greater than that in the phosphoric etching groups(P0·05).Conclusion HF etching, deglazing by grinding and silanating can all increase the shear bond strength between metal bracket and porcelain. Surface silanating of porcelain is a better surface treatmentwhen metal brackets bonded to porcelain.
