Effects of CO 2 laser debonding of a ceramic bracket on the mechanical properties of enamel

Masahiro Iijima, Yoshitaka Yasuda, Takeshi Muguruma, Itaru Mizoguchi

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Objective: To investigate the effects of CO 2 laser debonding of a ceramic bracket on the mechanical properties of tooth enamel. Materials and Methods: Fifty-three human premolars were used in this study. The temperature changes of cross-sectioned specimens during laser irradiation were monitored with an infrared thermographic microscope system. Different laser output settings (3, 4, 5, and 6 W) were compared. The shear bond strength of brackets after laser irradiation was measured for specimens bonded with a conventional etch and rinse adhesive or with a self-etching adhesive, and the adhesive remnant index score was calculated. The hardness and elastic modulus of crosssectioned enamel after laser irradiation were investigated by the nanoindentation test. Data were compared by one-way and two-way analysis of variance, followed by the Scheffé test. Results: The temperature of enamel increased by about 200°C under CO 2 laser irradiation with a relatively high output (5 and 6 W), and a temperature increase of about 100°C to 150°C was seen under laser irradiation with a low output (3 and 4 W). The bracket shear bond strength decreased under all laser irradiation conditions. The hardness and elastic modulus of enamel were not affected by CO 2 laser debonding. Conclusion: CO 2 laser debonding may not cause iatrogenic damage to enamel.

Original languageEnglish
Pages (from-to)1029-1035
Number of pages7
JournalAngle Orthodontist
Volume80
Issue number6
DOIs
Publication statusPublished - 2010 Nov 1
Externally publishedYes

Keywords

  • Enamel
  • Infrared thermography
  • Laser debonding
  • Nanoindentation test
  • Shear bond strength

ASJC Scopus subject areas

  • Orthodontics

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