INTRODUCTION: The purpose of this in-vitro study was to develop a new method to debond ceramic brackets by scanning with an Er:YAG laser. METHODS:Sixty bovine mandibular incisors were randomly divided into 2 groups of 30. Polycrystalline ceramic brackets were placed on their labial surfaces by using the orthodontic composite adhesive Transbond XT (3M Unitek, Monrovia, Calif) and light cured for a total of 40 seconds. The first group was the control group, with no laser application performed. The Er:YAG laser was used on each bracket in the study group at 4.2 W for 9 seconds with the scanning method. The force required for debonding the brackets was applied 45 seconds after laser exposure. Shear bond strengths were measured in megapascals with a universal testing machine, and adhesive remnant index scores were assigned to each specimen. RESULTS: 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 the adhesive remnant index scores of 2 or 3. CONCLUSIONS: The application of the Er:YAG laser with the scanning method is effective for debonding ceramic brackets by degrading the adhesive through thermal softening. Copyright (c) 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.
RCT Entities:
INTRODUCTION: The purpose of this in-vitro study was to develop a new method to debond ceramic brackets by scanning with an Er:YAG laser. METHODS: Sixty bovine mandibular incisors were randomly divided into 2 groups of 30. Polycrystalline ceramic brackets were placed on their labial surfaces by using the orthodontic composite adhesive Transbond XT (3M Unitek, Monrovia, Calif) and light cured for a total of 40 seconds. The first group was the control group, with no laser application performed. The Er:YAG laser was used on each bracket in the study group at 4.2 W for 9 seconds with the scanning method. The force required for debonding the brackets was applied 45 seconds after laser exposure. Shear bond strengths were measured in megapascals with a universal testing machine, and adhesive remnant index scores were assigned to each specimen. RESULTS: 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 the adhesive remnant index scores of 2 or 3. CONCLUSIONS: The application of the Er:YAG laser with the scanning method is effective for debonding ceramic brackets by degrading the adhesive through thermal softening. Copyright (c) 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.