Reusability of Orthodontic Brackets Removed by Different Debonding Techniques

Objective: To evaluate impulse debonding in comparison to three conventional methods for bracket removal with respect to the reusability of brackets. Methods: Ninety-six osteotomed 3rd molars were randomly distributed into two study groups (n=48) for bonding of a 0.018“ Ormesh premolar bracket; Ormco) with either Mono-Lok2 or Fuji Ortho LC. These two groups were subsequently again randomly divided each into 4 subgroups (n=12), and assigned to one of the described bracket debonding method groups. Debonding was performed with (1) a bracket removal plier (Dentaurum), (2) a black cutter (Dentaurum), (3) the lift off debracking instrument (LODI; 3M-Unitek), (4) an impulse / air pressure device, (CoronaFlex, KaVo). Brackets were subsequently tested on reusability and reworkability (1) visually with 2x magnification, and (2) by testing with a 0.017x0.025“ archwire. Portions of reusable brackets were compared separately with regard to removal mode and adhesives, respectively, by Fisher's exact test (α=5%). Results: Disregarding the method used for the bracket removal, of those bonded with Fuji Ortho LC 81% (n=39) of the brackets were judged as reworkable. Of those bonded with Mono-Lok2, 56% (n=27) of the brackets were judged as reworkable. Statistically, the portions of reusable brackets are thus significant (p<0.01). All brackets of both adhesive groups removed with either the LODI or the impulse device were reusable, whereas 79% (46%) of the brackets removed with the removal plier (cutter, respectively) were not. Especially in combination with the MonoLok composite adhesive, plier and cutter results were miserable. Portions of reusable brackets differed significantly between the removal modes (p< 0.01). Conclusion: From the view of the bracket reusability, the black cutter and the bracket removal plier cannot be recommended for debonding brackets.