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 aim of this study was to compare shear bond strength of two methods of repairing fractured porcelain utilizing either resin composite [Clearfil APX] or porcelain [Duceram LFC] in conjugation with two currently used adhesives [Optibond F and Clearfill liner bond II]. It also evaluated the effect of storage and thermocycling on the repair bond strength. Eighty, metal discs were prepared 10 mm diameter x 1mm thickness [Co bond. Cobalt Chromium alloy] to which a layer of porcelain 1.5mm thick was fused. The porcelain fused to metal discs [PFM] that were treated with 8% hydrofluoric acid and silanated, were divided into two main groups [I and II] according to the repair material [composite or porcelain]. Each main group was divided into two sub groups [A and B] according to the adhesive used for bonding [Optibond or Clearfill]. After bonding the repair materials to the PFM discs, each subgroup was divided into two divisions [i and ii] according to the storage time [45 or 90 days] in an incubator at 37°C. All samples were subjected to 500 thermal cycle [5-55°C, 1 min dwell time]. Shear bond strengths were determined using a universal testing machine at 5 mm/min. cross head speed, data were collected, tabulated and statistically analysed using student's t test at p < 0.05. Results showed that, bonding agents containing 4-META adhesive developed it strength that could be considered adequate for porcelain repair. The repair system utilizing composite [gp I] showed higher mean bond strength [19.14 MPa] than that recorded in gp II utilizing porcelain [17.66], However, the statistical difference was not significant [p > 0.051. The storage time was found to adversely affect the bond strength. Further clinical studies were recommended
ABSTRACT
The aim of this study was to reveal the reliability of two in vitro tests [bond strength and microleakage] in predicting the clinical performance of three tested adhesives [Scotch Bond Multi Purpose, Adper Single Bond and Adper Prompt - L - Pop] which were used to bond Filtek Supreme composite resin to the tooth structure. The study was conducted on 63 sound human molars, that were divided into three divisions [21 each] for performing the bond strength test by two methods [Shear and Pushout] while teeth in the 3[rd] division were utilized for dye penetration microleakage test using 2-D and 3-D scoring methods. For each test, samples were divided to 3 groups [7 each] according to the current adhesives under investigation. All the prepared samples were subjected to 600 thermal cycle [5 - 55 °C. 2 min dwell time]. Data were collected, tabulated and statistically analysed using 2 and 3 way ANOVA tests. Results showed a sig. diff: [P < 0.05] between the two methods of testing the bond strength [regardless the type of adhesive] where the mean push - out strength value [21.3 Mpa] was sig. higher than that revealed by the shear method [17.06 MPa]. However no sig. diff. [P > 0.05] was found between the two scoring methods of microleakage test. While the study revealed an inconsistent pattern of relation between the data presented by both tests, it could be predicted that, the use of an all in one adhesive [Prompt - L - Pop] for bonding the tested composite resin to tooth structure is promising
ABSTRACT
The aim of this study was to investigate the effect of different dentin bonding systems and a surface sealant on marginal leakage. A wear testing device was used on the buccal and lingual surface and the dye penetration method recorded the extent of leakage. A total of 120 lower molars with buccal and lingual class V cavities were used for this study in four groups. It was found that Scotchbond multipurpose bonding agent showed the least leakage followed by tenure, and Prisma Universal, while Scotchbond 2 was the most leaking group. However, using the surface penetrating sealant decreased the leakage of all groups