title: Evaluation of shear bond strength between zirconia core and ceramic veneers fabricated by pressing and layering techniques: In vitro study.
abstract: BACKGROUND
  Although ceramic veneered on to zirconia core have been in use for quite some time, information regarding the comparative evaluation of the Shear bond strength of Pressable & Layered ceramic veneered on to zirconia core is limited.
  
  
  OBJECTIVE
  To evaluate the shear bond strength of zirconia core and ceramic veneer fabricated by two different techniques, Layering (Noritake CZR) and Pressing (Noritake, CZR Press).
  
  
  METHODS
  20 samples of zirconia blocks were fabricated and the samples were divided into group A & B. Group A - Ceramic Veneered over zirconia core by pressing using Noritake CZR Press. Group B - Ceramic Veneered over zirconia core by layering using Noritake CZR. The veneered specimens were mounted on to the center of a PVC tube using self-cure acrylic resin leaving 3 mm of the veneered surface exposed as cantilever. Using a Universal testing machine the blocks were loaded up to failure.
  
  
  RESULTS
  The results were tabulated by using independent samples t-test. The mean shear bond strength for Pressed specimens was 12.458 ± 1.63(S.D) MPa and for layered specimens was 8.458 ± 0.845(S.D) MPa.
  
  
  CONCLUSIONS
  Pressed specimens performed significantly better than the layered specimen with a P value 0.001. Clinicians and dental laboratory technicians should consider the use of pressed ceramics as an alternative to traditional layering procedures to reduce the chances of chipping or de-lamination of ceramics.
authors.affiliation: Division of Prosthodontics, Oxford Dental College and Hospital, Bengaluru, Karnataka, India.
authors.forename: M
authors.initials: M
authors.lastname: Subash
authors.affiliation: Division of Prosthodontics, Rajah Muthiah Dental College and Hospital, Annamalai University, Chidambaram, Tamil Nadu, India.
authors.forename: D
authors.initials: D
authors.lastname: Vijitha
authors.affiliation: Division of Prosthodontics, Rajah Muthiah Dental College and Hospital, Annamalai University, Chidambaram, Tamil Nadu, India.
authors.forename: Saikat
authors.initials: S
authors.lastname: Deb
authors.affiliation: Division of Prosthodontics, Rajah Muthiah Dental College and Hospital, Annamalai University, Chidambaram, Tamil Nadu, India.
authors.forename: A
authors.initials: A
authors.lastname: Satish
authors.affiliation: Division of Prosthodontics, Rajah Muthiah Dental College and Hospital, Annamalai University, Chidambaram, Tamil Nadu, India.
authors.forename: N
authors.initials: N
authors.lastname: Mahendirakumar
keywords: Layered ceramics; pressable ceramics; shear bond strength of zirconia; zirconia core