Bonding And Re-bonding Strength Among3Orthodontic Adhesive Systems With Recycled Brackets

Study backgroundIn order to avoid bracket failure, good and high bond strengths are required during treatment while brackets in function. Surface treatment of rebonded enamel, as well as recycled bracket base will improve contact area of the bracket to the tooth.Objectivesto compare SBS of different composite brand with famous one and examine the effect of enamel condition with different etching time in combination with in-office bracket base condition with green stone and sandblasting, however, is yet not well described.MethodsIn this study we examine clinical SBS range and adhesive remnant index (ARI) of two different adhesive resin brands Xihubiom light cured (Westlake Biomaterial CO.LTD, China), and Tianjin chemical-cured (Tianjin Synthetic Material, tianjin city, Road29,China) compared with famous and widely used Transbond XT light cured (3M Unitek, Monrovia, Calif). After that, debonded brackets were recycled with two methods; sandblasting treatment using50μm aluminum oxide particles under a pressure of0.45MPa, and green stone drilling. In all enamel samples, residual resin were removed by tungsten carbide bur and etching rebonded enamel surface carried under various etching time;30s,60s, and0s etching was done. Samples were rebonded to enamel surface by Xihubiom light cured composite. All specimens were debonded using Eplexor500N (Gabo, Germany) testing machine with crosshead speed of1mm/min, then shear bond strength and rebonded strength were measured, respectively. The ARI was re-scored.Scanning electron microscope (SEM)([Jeol/JLM-5200, Tokyo, Japan) for enamel surface after debonding. ResultsTransbond XT resin (18.23MPa) had higher shear bond strength than any of the other bonding material but there were no statistically significant at P>0.05, among Transbond XT, Xihubiom resin (16.99MPa) and Tianjin resin (16.85MPa). Samples re-cemented with Xihubiom resin had rebonded strength values as follow; sandblasted brackets with enamel etching for30seconds SD3(13.49MPa) had the highest rebonded strength values than the others. There were no statistically significant at P>0.05among SD3, sandblasted brackets with enamel etching for60seconds SD6(12.39MPa), drilled brackets base with enamel etching for30seconds DD3(7MPa), and drilled brackets base with enamel etching for60seconds DD6(6.18MPA). However, SD3, and SD6had RBS values statistically significant P<0.05than drilled brackets base with no enamel etching DD (4.58MPa) and the value for SD3were statistically significant P<0.05than sandblasted brackets with no enamel etching SD (5.85MPa). Significant differences were found in the ARI scores.Conclusion1) The shear bond values of3adhesives are clinically acceptable.2) For economic saving we recommend the use of Xihubiom resin for bonding and rebonding brackets.3) Recycling brackets base with50μm aluminum oxide sandblasting and enamel etching for30seconds had the best rebonding strength when compared to green stone treated brackets base.4) In the second debonding one hour After cementation, enamel re-condition with tungsten Carbide bur only is insufficient as a conditioning procedure but, if combination with acid etching, reasonable rebonding strength can be achieved.