Abstract

EVALUATION OF EFFECT OF ACID ETCH ON SHEAR BOND STRENGTH OF TWO CERAMIC REPAIR TECHNIQUES

Atyaf M. AL-Naser* and Suha Fadhil Dulaimi

ABSTRACT

Background: Metal ceramic crown and fixed partial dentures could
expose to fracture of ceramic veneer with and without metal exposure.
The replacement of this restoration is costly, time consuming and
removal of restoration could expose abutment teeth to fracture and this
lead to generation of new repair systems with different surface
treatment. Objective: The main objective of present study was to
evaluate the effect of two type of acid etch with two type of ceramic
repair technique on the shear bond strength of two different failures of
metal ceramic restoration. Subject and methods: Eighty metal discs
(20 mm in diameter × 0.7 mm thick) were fabricated from nickelchromium
alloy (Kera, USA). Feldspathic porcelain (VITA, Germany)
were applied over one test surface of the discs in the thickness of
1.8 mm followed by conventional firing. The defect, was created in
1/4th area of the metal-ceramic discs (40 samples exposure metal and
40 sample with exposure ceramic). Then all samples were sandblasted
with (50μ AL2O3) and beveled subdivided according to type of repair technique into 40
samples repaired with Ivoclar vivadent repair technique (with and without 37% phosphoric
acid), and 40 samples repaired with Pulpdent repair technique (with and without 9.6%
hydrofluoric acid). After that all the repaired samples were stored in distilled water at (37°c)
for 24h. After thermocyclying at( 6-60°c), all the samples were stored at (37°c) for additional 7 days then shear bond strength of all the samples were measured with Instron Universal testing machine. Results: One way ANOVA showed non-significant effect through application 37% phosphoric acid and sandblasting with Ivoclar repair technique for exposure metal and exposure ceramic. Also one way ANOVA showed non-significant effect through application 9.6% hydrofluoric acid and sandblasting with Pulpdent repair technique for exposure metal and exposure ceramic of MCR. Comparison between two techniques using student s t - test showed, Pulpdent repair technique with application 9.6% hydrofluoric acid and sandblasting for exposure metal and exposure ceramic of metal ceramic restoration resulted in higher significant shear bond strength in comparison to Ivoclar repair technique with application of 37% phosphoric acid for exposure metal and exposure ceramic of metal ceramic restoration. Pulpdent repair technique and Ivoclar repair technique without acid resulted in similar effect on shear bond strength of exposure metal and exposure ceramic of MCR.

Keywords: Metal ceramic repair, Acid etch, sandblasting, shear bond strength.