Laser energy can be used to debond ceramic brackets, according to a study in the American Journal of Orthodontics and Dentofacial Orthopedics (August 2010, Vol. 138:2, pp. 195-200).
Researchers from Yeditepe University in Istanbul wanted to develop a new way to debond ceramic brackets by scanning the brackets with an Er:YAG laser.
For their in vitro study, they randomly divided 60 bovine mandibular incisors into two groups of 30. Polycrystalline ceramic brackets were placed on their labial surfaces using an orthodontic composite adhesive (Transbond XT, 3M Unitek) and light cured for 40 seconds.
The control group was not laser scanned. In the other group, Er:YAG laser energy was applied to each bracket at 4.2 W for 9 seconds. The force required for debonding the brackets was applied 45 seconds after laser exposure.
Statistically significant (p < 0.001) lower shear bond strengths were found in the laser group (9.52 MPa) compared with the control group (20.75 MPa). Likewise, the adhesive remnant index scores were statistically different (p < 0.001); the laser group had twice as many samples with adhesive, with an adhesive remnant index score of 2 or 3.
"The application of the Er:YAG laser with the scanning method is effective for debonding ceramic brackets by degrading the adhesive through thermal softening," the researchers concluded.
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