بررسی اثر دو نوع ماده قالب گیری بر میزان استحکام برشی باند پرسلن به عاج فورا سیل شده

Abstract

Introduction: Immediate dentin sealing with dentin bonding agents at once after cavity preparation and before impression is recommended. The purpose of this study was ruminating the effects of two current impression materials on shear bond strength of porcelain bonded to immediately sealed dentin. Materials and methods: 45 intact human premolars extracted for orthodontic treatments were obtained and immediately after grinding the buccal enamel and creation a smooth dentinal surface, immediate dentin sealing with dentin bonding agent AdperTM Single Bond were performed. Then specimens randomly and according to the method of the performance, distributed in three groups of fifteen pieces as below: 1) Bonding the porcelain specimens with dual cured Relay X ARC (3M ESPE) cement, to immediately sealed dentin. 2) Emerging the tooth specimens in condensational silicon impression material (Speedex), then applying an additional adhesive layer and bonding the porcelain specimens according to group 1. 3) Emerging the specimens in polyether impression material (Impregum), applying an additional adhesive layer and bonding the porcelain specimens according to group 1. After 24 hour holding specimens in 37oC distilled water and 500 cycle thermo cycling between 5±2oC–55±2oC, shear bond strengths were measured with Hounsfield Test Equipment model H5K-S in the speed of 0.5 mm/min. One Way ANOVA test was used to compare shear bond strengths of groups and Tukey test for 2 by 2 comparisons of bond strengths between groups. Results: The most mean of shear bond strength was obtained in group 1 (13.13±3.93) and the least was for group 3 (8.15±1.92). The statistical difference between the groups was significant (F2, 42 = 13.6, P < 0.0005). The difference of shear bond strength between groups 1 and 2 was not statistically significant (P = 0.31) but it was significant between 1 and 2 with 3 (P = 0.0005 for 1 and 3 and P=0.002 for 2 and 3).