RESUMO
The purpose of this study was to evaluate the clinical usefulness of plasma arc light which can reduce the curing time dramatically compared by shear bond strengths and failure patterns of the brackets bonded with visible light in direct bracket bonding. Some kinds of brackets were bonded with the Transbond(R) to the human premolars which were embedded in the resin blocks according to the various conditions. After bonding, the shear bond strength was tested by Instron universal testing machine and in addition , the amount of residual adhesive remaining on the tooth after debonding was measured by the stereoscope and assessed with adhesive remnant index(ARI). The results were as follows : 1. When plasma arc light was used for bonding the brackets, the shear bond strength was clinically sufficient in both metal and ceramic brackets, but resin brackets showed significantly lower bond strength but which was clinically useful. 2. When metal brackets were bonded using visible light, there was no significant difference in shear bond strength due to the light-curing time and the bond strength was clinically sufficient. 3. When the adhesive failure patterns of brackets bonded with plasma arc light were observed by using the adhesive remnant index, the bond failure of the metal and resin bracket occurred more frequently at bracket-adhesive interface but the failure of the ceramic bracket occurred more frequently at enamel-adhesive interface. 4. There was no statistically significant difference of the shear bond strength and adhesive failure pattern between metal bracket bonded for 2 seconds by curing with plasma arc light and 10 seconds by curing with visible light. 6. When metal brackets were bonded using plasma arc light, the shear bond strength decreased as the distance from the light source increased. The above results suggest that plasma arc light can be clinically useful for bonding the brackets without fear of the decrease of the shear bond strength.
Assuntos
Humanos , Adesivos , Dente Pré-Molar , Cerâmica , Luz , Plasma , DenteRESUMO
Objective:To evaluate the effects of different enamel conditioners in combination with an adhesive on the shear bond strength and the adhesive remnant index in vitro.Methods:One hundred and eight permanent healthy premolars from orthodontic patients and fresh saliva from a healthy young volunteer were collected.The teeth were cleaned,dried and etched by phosphoric acid,polyacrylic acid or Transbond plus SEP respectively(36 teeth for each agent).Then the teeth were bonded to brachet by RMGICs with the presence of water,saliva on the tooth surface or without any of them respectively(12 teeth in each group).After bonding,all samples were tested on a testing machine of Instron.Shear bond strength and adhesive remnant index were recorded.Results:Highest mean shear bond strength was observed in the group of teeth etched by Traspond plus SEP and bonded by RMGICs with the presence of saliva.Higher mean shear bond strength was obtained with the presence of saliva or water on the tooth surface than without any of them.Conclusion:Transbond plus SEP conditioning followed by RMGICs bonding may produce high shear bond strength between moistured tooth surface and brachet.