A POSTTREATMENT EVALUATION OF MULTIBONDED CERAMIC BRACKETS IN ORTHODONTICS

The purpose of this study was to perform a clinical evaluation of cera mic brackets with silane-coated bases for chemical (Transcend) and mic rocrystalline bases for mechanical (Transcend 2000) retention. The sam ple consisted of 49 consecutive patients; the first 30 were treated wi th brackets with chemical retention and the following 19 with brackets with mechanical retention. For each patient the brackets on one side of the mouth were assigned at random to be bonded with Concise and the other with Transbond as recommended by the manufacturers. Levelling a nd alignment of severely displaced roots was initiated with superelast ic wires and completed with stainless steel wires. Any space closure o r correction of interarch discrepancy was performed with rectangular s tainless steel wires. The brackets with chemical retention were remove d with a torsional rotation debonding wrench, and those with mechanica l retention with a tensile debonding plier. The bond failure rate was low,,with no difference between the two bracket types or between brack ets bonded with Concise and Transbond. Bracket fracture was a signific ant clinical problem, both during active treatment and at the time of appliance removal. New teeth with formation of pronounced enamel crack s were seen in 20.6 and 10.5 per cent of the teeth treated with bracke ts with chemical and mechanical retention, respectively (P < 0.001), w ith no difference between teeth bonded with Concise and Transbond. Ena mel tear-outs were seen in 3 of the 544 and in 1 of the 344 teeth trea ted with the respective types of bracket. These teeth were bonded with Concise.