title: A comparative evaluation of the shear bond strength of five different orthodontic bonding agents polymerized using halogen and light-emitting diode curing lights: an in vitro investigation.
abstract: OBJECTIVE
  With the introduction of photosensitive (light-activated) restorative materials in orthodontics, various methods have been suggested to enhance the polymerization of the materials used, including use of more powerful light curing devices. Bond strength is an important property and determines the amount of force delivered and the treatment duration. Many light-cured bonding materials have become popular but it is the need of the hour to determine the bonding agent that is the most efficient and has the desired bond strength.
  
  
  OBJECTIVE
  To evaluate and compare the shear bond strengths of five different orthodontic light cure bonding materials cured with traditional halogen light and low-intensity light-emitting diode (LED) light curing unit.
  
  
  METHODS
  100 human maxillary premolar teeth, extracted for orthodontic purpose, were used to prepare the samples. 100 maxillary stainless steel bicuspid brackets of 0.018 slot of Roth prescription, manufactured by D-tech Company, were bonded to the prepared tooth surfaces of the mounted samples using five different orthodontic bracket bonding light-cured materials, namely, Enlight, Fuji Ortho LC (resin-modified glass ionomer cement), Orthobond LC, Relybond, and Transbond XT. The bond strength was tested on an Instron Universal testing machine (model no. 5582).
  
  
  RESULTS
  In Group 1 (halogen group), Enlight showed the highest shear bond strength (16.4 MPa) and Fuji Ortho LC showed the least bond strength (6.59 MPa) (P value 0.000). In Group 2 (LED group), Transbond showed the highest mean shear bond strength (14.6 MPa) and Orthobond LC showed the least mean shear bond strength (6.27 MPa) (P value 0.000). There was no statistically significant difference in the shear bond strength values of all samples cured using either halogen (mean 11.49 MPa) or LED (mean 11.20 MPa), as the P value was 0.713.
  
  
  CONCLUSIONS
  Polymerization with both halogen and LED resulted in shear bond strength values which were above the clinically acceptable range given by Reynolds. The LED light curing units produced comparable shear bond strength to that of halogen curing units.
authors.affiliation: Department of Prosthodontics, VSPM Dental College and Research Centre, Nagpur, India.
authors.forename: Sujoy
authors.initials: S
authors.lastname: Banerjee
authors.forename: Rajlakshmi
authors.initials: R
authors.lastname: Banerjee
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000180:Acrylic Resins / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D001641:Bicuspid; D055117:Curing Lights, Dental / Q000145:classification*; D003722:Dental Alloys / Q000737:chemistry; D003738:Dental Cements / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000295:instrumentation*; D008422:Materials Testing; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000737:chemistry; D058105:Polymerization; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical
chemical_list: D000180:Acrylic Resins; D000538:Aluminum Silicates; D003722:Dental Alloys; D003738:Dental Cements; C418867:Enlight; C095451:Fuji Ortho LC; D005899:Glass Ionomer Cements; D010756:Phosphoric Acids; C097531:Rely a Bond system; D019279:Resin Cements; C477790:Transbond XT; D013193:Stainless Steel; C030242:phosphoric acid