title: Effects of Diode Laser Debonding of Ceramic Brackets on Enamel Surface and Pulpal Temperature.
abstract: Debonding of ceramic brackets due to their high bond strength and low fracture toughness is one of the most challenging complications of orthodontic clinicians. Application of lasers might be effective in the debonding of ceramic brackets as they reduce bond strength of resins and, therefore, can eliminate the risk of enamel damage. However, the thermal effects of laser radiation on dental tissue can cause undesirable results. The aim of this study is to evaluate the enamel surface characteristics and pulpal temperature changes of teeth after debonding of ceramic brackets with or without laser light.
  
  
  
  Thirty polycrystalline brackets were bonded to 30 intact extracted premolars, and later debonded conventionally or through a diode laser (2.5 W, 980 nm). The laser was applied for 10 seconds with sweeping movement. After debonding, the adhesive remnant index (ARI), the lengths and frequency of enamel cracks were compared among the groups. The increase in intrapulpal temperature was also measured. The collected data were analyzed by Chi-squared test and paired t-test using Statistical Package for Social Sciences (SPSS) software.
  
  
  
  There was no case of enamel fracture in none of the groups. Laser debonding caused a significant decrease in the frequency and lengths of enamel cracks, compared to conventional debonding. In laser debonding group, the increase in intrapulpal temperature (1.46°C) was significantly below the benchmark of 5.5°C for all the specimens. No significant difference was observed in ARI scores among the groups.
  
  
  
  Laser-assisted debonding of ceramic brackets could reduce the risk of enamel damage, without causing thermal damage to the pulp. However, some increases in the length and frequency of enamel cracks should be expected with all debonding methods.
authors.affiliation: Department of Orthodontics, Shahid Sadoughi University of Medical Sciences Yazd, Iran.
authors.forename: Soghra
authors.initials: S
authors.lastname: Yassaei
authors.affiliation: Department of Orthodontics, Shahid Sadoughi University of Medical Sciences Yazd, Iran.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Soleimanian
authors.affiliation: Postgraduate Student, Department of Orthodontics, Shahid Sadoughi University of Medical Sciences Yazd, Iran, Phone: 989159968117 e-mail: z_3nik@yahoo.com.
authors.forename: Zahra Ebrahimi
authors.initials: ZE
authors.lastname: Nik
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D001831:Body Temperature / Q000528:radiation effects*; D002516:Ceramics / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods; D003738:Dental Cements / Q000737:chemistry; D017005:Dental Debonding / Q000295:instrumentation* / Q000379:methods; D003743:Dental Enamel / Q000528:radiation effects*; D003764:Dental Materials / Q000737:chemistry*; D003782:Dental Pulp / Q000528:radiation effects*; D006801:Humans; D054023:Lasers, Semiconductor; D055115:Light-Curing of Dental Adhesives / Q000379:methods; D008422:Materials Testing; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000737:chemistry; D011897:Random Allocation; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003738:Dental Cements; D003764:Dental Materials; D010756:Phosphoric Acids; C030242:phosphoric acid
keywords: Ceramic bracket; Diode laser; Debonding; Enamel damage; Pulpal temperature; Laboratory research