title: The Shear Bond Strength of Porcelain Laminate to Prepared and Unprepared Anterior Teeth.
abstract: BACKGROUND
  Porcelain laminate veneer is an esthetic restoration used as an alternative to full veneer crowns and requires minimal tooth preparation. In restoration with porcelain laminate veneers, both the longevity of the laminate and conservation of the sound tooth structure are imperative.
  
  
  OBJECTIVE
  The present study aimed to investigate the shear bond strength of porcelain laminates to prepared- and unprepared- anterior teeth in order to compare their longevity and success rate.
  
  
  METHODS
  Thirty extracted maxillary central incisors were randomly divided into 3 groups regarding their preparation methods. The preparation methods were full-preparation in group A, full-preparation and finishing with fine diamond bur in group B, and no-preparation, only grinding with diamond bur in group C. After conditioning the teeth, ceramic veneers (IP S e.max) were silanated and then cemented with DuoLink luting cement. The shear bond strength was measured for each group and failure mode was determined by stereomicroscopic examination.
  
  
  RESULTS
  Group C exhibited the highest shear bond strength. The shear bond strength was significantly different between groups C and B (p< 0.05). However, the difference between group A and C was insignificant, as was the difference between group A and B (p> 0.05). Adhesion failure mode was found to be more common than the cohesive mode.
  
  
  CONCLUSIONS
  Regarding the shear bond strength of unprepared anterior teeth to porcelain laminate veneers yielded by this study, no-preparation veneers might be used when the enamel is affected by wearing, trauma, or abrasion. It can also be used in patients who refuse the treatments which involve tooth reduction and preparation.
authors.affiliation: Dept. Operative Dentistry and Biomaterials of Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Ali Asghar
authors.initials: AA
authors.lastname: Alavi
authors.affiliation: Dept. of Orthodontic, School of Dentistry, Yasuj University of Medical Sciences, Yasuj, Iran.
authors.forename: Zeinab
authors.initials: Z
authors.lastname: Behroozi
authors.affiliation: Dept. Operative Dentistry, School of Dentistry, Yasuj University of Medical Sciences, Yasuj, Iran.
authors.forename: Farid
authors.initials: F
authors.lastname: Nik Eghbal
keywords:  Dental bonding ;  Dental laminate ;  Dental porcelain ;  Shear strength ;  Tooth preparation; Dental veneer 