title: Influence of ceramic (feldspathic) surface treatments on the micro-shear bond strength of composite resin.
abstract: OBJECTIVE
  To test the null hypothesis that surface treatment has no influence on the micro-shear bond strength between orthodontic composite resin cement and ceramics (feldspathic porcelain).
  
  
  METHODS
  Circular specimens of feldspathic porcelain were fabricated and randomly divided into six groups: (1) no treatment; (2) treatment with a mixture of acidic primer and silane agent for 20 seconds; (3) etching with 9.5% hydrofluoric acid; (4) etching with 9.5% hydrofluoric acid and coating with a mixture of acidic primer and silane agent for 20 seconds; (5) airborne-particle abrasion with 50-mum aluminum oxide; and (6) airborne-particle abrasion and coating with a mixture of acidic primer and silane agent for 20 seconds. The porcelain disks were then bonded to resin cylinders with composite resin cement. A micro-shear bond test was carried out to measure the bond strength. Moreover, each ceramic surface was observed morphologically by scanning electron microscopy. One-way analysis of covariance was used to compare the groups for differences in micro-shear bond strength.
  
  
  RESULTS
  The mean micro-shear bond strength varied as a function of surface treatment. It ranged from 3.7 to 20.8 MPa. The highest values for micro-shear bond strength were found when the surface was acid-etched with hydrofluoric acid and coated with silane. On the other hand, the control group (no treatment) had significantly lower micro-shear bond strength than all the other groups.
  
  
  CONCLUSIONS
  The null hypothesis that the surface treatment has no influence on the micro-shear bond strength of orthodontic composite resin was rejected. The bond strength between ceramics and orthodontic resin cement is affected by the ceramic surface treatment. The bond failure was of the adhesive type, except with the hydrofluoric acid + silane group, where it was a cohesive bond failure.
authors.affiliation: Department of Orthodontics, Indiana School of Dentistry, Indianapolis, IN, USA. syadav@iupui.edu
authors.forename: Sumit
authors.initials: S
authors.lastname: Yadav
authors.forename: Madhur
authors.initials: M
authors.lastname: Upadhyay
authors.forename: Gilberto Antonio
authors.initials: GA
authors.lastname: Borges
authors.forename: W Eugene
authors.initials: WE
authors.lastname: Roberts
mesh_terms: D000538:Aluminum Silicates; D045662:Dental Etching / Q000379:methods; D003776:Dental Porcelain; D003799:Dental Stress Analysis; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D016910:Orthodontic Brackets; D017680:Potassium Compounds; D011897:Random Allocation; D019279:Resin Cements; D033081:Shear Strength; D013499:Surface Properties
chemical_list: D000538:Aluminum Silicates; D017680:Potassium Compounds; D019279:Resin Cements; D003776:Dental Porcelain; C016447:feldspar