ABSTRACT
Purpose: To evaluate the effectiveness of three adhesives for their ability to seal amalgam/tooth interface through a microleakage and SEM correlation study
Materials and Methods: Class V cavities were prepared on the buccal surface of 64 non carious human lower molers with occlusal margin in enamel and the cervical margins in dentin. Samples were randomly divided into 4 groups [16 each], according the adhesive used. Group I [control] utilized no adhesive, group II utilized optibond adhesive, group III, utilized SBMP+ adhesive while group IV utilized permaquick. All the cavities were restored with valiant, a palladium enriched high Cu amalgam. Half the no. of samples in each group was subjected to along term thermomechanical loading equal to 6 yrs clinical service, comprising 3600 thermal cycle [5-55°C, 2 min dwell time, 10 sec. transfer time], and 1.440.000 load cycle [49 N at 1-7 HZ] applied in the center of the occlusal surface. The rest of the samples were used for obtaining the base line data. All samples were subjected to a dye penetration test through immersion in 2% methylene blue dye for 4 hours, then sectioned and scored for microleakage. The cut sections were prepared for SEM to examine the tooth/ restoration interfaces features which were also scored. Data were collected and statistically analysed using Kruskal Wallis and Man Whitnney U test at P < 0.05
Results: Non of the adhesives tested consistently prevented microleakage, neither at the base line nor after thermomechanical loading, however, they were significantly different from the control group. On the other hand, group Ill utilizing SBMP+ adhesive showed the best results followed by group II [optibond adhesive]. While group IV utilizing permaquick showed the highest leakage values. All groups showed significantly less leakage at the occlusal compared to the cervical margin [P < 0.01]. Scanning electron microscopy examination showed different interfacial failure patterns within and between test groups, their recorded scores revealed similar results to those of the leakage. Pearson correlation test showed a significant positive correlation between the SEM and the leakage scores [P = 0.003]
ABSTRACT
The present study was performed to compare the reproducibility of each of the porcelain and composite laminates to the selected shade [A-2]. The effects of the laminate thickness [0.5 mm and 1 mm] and that of the luting resin shades on the final shade of the laminate samples were also investigated. This study was carried out on 84 laminate samples i.e 42 porcelain laminate samples [IPS Corum] and 42 composite laminate samples [Tetric Ceram]. The shade of the laminate materials [porcelain/composite] which was used in fabrication of laminate was A-2. Each laminate sample was square in shape with a side length 10 mm. Half of the laminate samples had 0.5 mm thickness while the other half of the samples had 1 mm thickness. All of the laminate samples were cemented to standardized acrylic substrates. The shade of the substrates was C-4. Cementation of the laminate samples to the substrates was done by using different shades [A-1, A-2, A-3.5] of Aeliteflo and Tetric Flow flowable composites. The color difference between each cemented sample and the A-2 vita lumen shade guide was measured by using a spectro-colorimeter. The porcelain laminate was found to be the most reproducible material to the selected shade, and the statistical analysis revealed that the difference in shade reproducibility was highly significant when compared with composite laminate martial. The laminate samples with 1mm thickness had superior reproducibility than the laminate samples with 0.5 mm thickness. Aeliteflo luting resin was more reproducible to the selected shade than Tetric how luting resin. There was a highly significant relation between the shade of the luting resin and the final shade of laminate