title: In vitro evaluation of self-etch bonding in orthodontics using cyclic fatigue.
abstract: OBJECTIVE
  To evaluate the bond strength of a self-etch bonding system using static loading and cyclic fatigue with shear testing. This is a two-part evaluation; the first part will evaluate shear testing, the second part tensile testing.
  
  
  METHODS
  Bovine teeth (n = 82) were randomly distributed to either a self-etch (Transbond Plus) or total-etch (37% phosphoric-acid + Transbond XT) group. The static shear (SSBS) and cyclic shear (CSBS) bond strengths were measured 24 hours after the bonding of mesh-based brackets. The adhesive remnant index (ARI) and failure sites were evaluated.
  
  
  RESULTS
  The mean SSBS was 34.25 ± 9.21 and 24.64 ± 9.42 MPa for the total- and self-etch groups, respectively. CSBS was 24.07 ± 0.65 MPa and 18.92 ± 1.08 MPa for the total- and self-etch groups, respectively. Cyclic loading produced lower bond strengths compared to static testing for both adhesives; the difference was only statistically significant for the total-etch system. Comparison of the two materials showed a statistically significant difference between the two techniques. The total-etch had higher bond strengths than the self-etch bonding system. The samples showed a predominance of ARI scored of 2 and 1, and their bonding failure sites were cohesive within the composite.
  
  
  CONCLUSIONS
  Cyclic loading, simulating occlusal forces, reduces the bond strength of both bonding systems. Even though the self-etch bonding system had lower shear bond strength than the total-etch system, both were still clinically acceptable.
authors.affiliation: Department of Preventive Sciences, College of Dentistry, King Abdul-Aziz University, Jeddah, Saudi Arabia. drmansoura@hotmail.com
authors.forename: Ameerah Yousef
authors.initials: AY
authors.lastname: Mansour
authors.forename: James L
authors.initials: JL
authors.lastname: Drummond
authors.forename: Carla A
authors.initials: CA
authors.lastname: Evans
authors.forename: Zuhair
authors.initials: Z
authors.lastname: Bakhsh
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000268:Adhesiveness; D000818:Animals; D002417:Cattle; D019245:Compressive Strength; D001840:Dental Bonding / Q000379:methods*; D003799:Dental Stress Analysis / Q000295:instrumentation; D008422:Materials Testing; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000737:chemistry; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors
chemical_list: D010756:Phosphoric Acids; D019279:Resin Cements; C429625:Transbond Plus Self-Etching Primer; C477790:Transbond XT; C030242:phosphoric acid