Evaluation of Shear Bond Strength of Composite to Feldspathic Porcelain after Porcelain Surface Treatment with CO₂ and Er:YAG lasers

  Dr. Shirinzad M .,¹ Dr. Fekrazad R .,² Dr. Rezaei-Soufi L ., ³ Dr. Yarmohammadi E.,¹ Dr. Jalalian SH. ⁴

  ¹ Assistant Professor, Department of Operative Dentistry, School of Dentistry, Hamadan University of Medical Science. Hamadan , Iran . ² Associate Professor , School of Dentistry, AJA University of Medical Sciences and Member of Laser in Dentistry Research Center, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran . ³ Member of Dental Research Center and Associated Professor, Operative Dentistry, School of Dentistry, Hamadan University of Medical Science. Hamadan , Iran . ⁴ Assistant Professor, Department of Operative Dentistry, School of Dentistry, Jundi Shapur University of Medical Sciences, Ahwaz, Iran .

  (Received 2 May, 2012 Accepted 16 Aug, 2012)

  Abstract

  Background and Aim : Fractured ceramic crowns can sometimes be repaired with composite resin. The aim of the current study was to determine the shear bond strength of composite to feldspathic porcelain after CO₂ and Er:YAG laser porcelain surface preparation .

  Materials and Methods : In this in-vitro study, 36 feldspathic porcelain blocksmeasuring 1*10*10 mm were divided into 3 groups of 12. Porcelain surfacesinthe first and second groupswere treated with 1.8W CO₂ laser and 5W Er:YAG laserirradiation, respectively. Third group specimens were subjected to 9.5% hydrofluoric acid surface conditioning. Allgroups received application ofsilane and adhesiveafterwards. A composite cylinder with 3.5 mm diameter and 5 mm height was bonded to specimens. In order to evaluate the shear bond strength,aUniversal Testing Machine withacrosshead speed of 1 mm/min was used. Statistical analysis was performed using one-way ANOVA and Tukey’s HSD test and P<0.05 was considered statistically significant .

  Results : The mean shear bond strength values (MPa) were 13.03±2.57%, 12.02 ±3.4 and 19.23±4.62, for the first, second and third groups respectively. One-way ANOVA revealed a statistically significant difference in this respect between the three groups (P< 0.001). 

  Tukey’s HSD testdemonstratedsignificant differences betweenthefirst and third groups (P= 0.000) as well as the second and third groups (P=0.000). However, no significant difference was detected betweenthe first and second groups (P =0.778).

  Conclusion : Consideringthe study results, CO₂or Er:YAG laser irradiationis not suggested as an appropriate alternative to hydrofluoric acid for surface preparationoffeldspathic porcelain.

  Key words : Dental porcelain , laser , hydrofluoric acid , shear strength

  Corresponding Author: Dr. Yarmohammadi E ., Assistant Professor, Department of Operative Dentistry, School of Dentistry, Hamadan University of Medical Science. Hamadan , Iran .

  e.mail: e.yarmohammadi@umsha.ac.ir