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 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