introduction: the aim of this study was to evaluate the composite surface treated by different powers of erbium-doped yttrium aluminum garnet (er:yag) laser in comparison with bur preparation via scanning electron microscope. methods: fourteen composite resin blocks with 15× 10 × 10 mm dimensions were used in this study. the samples were divided to seven groups as follow: group 1 (power: 1 w, e...

background and aims. bleaching may exert some negative effects on existing composite resin restorations. the aim of this study was to evaluate the effect of home bleaching on microleakage of fiber-reinforced and particle-filled composite resins. materials and methods. ninety class v cavities (1.5×2×3 mm) were prepared on the buccal surfaces of 90 bovine teeth. the teeth were randomly divided in...

objective: different ceramic repair systems have been reported for fractured ceramics. however, limited information is available concerning the bond strength of these systems especially after thermocycling. the aim of this in-vitro study was to determine the effect of thermocycling on the shear bond strength of composite-resin to feldspathic porcelain with and without silane pretreatment. mater...

statement of problem: in some clinical situations, repair of composite restorations is treatment of choice. improving the bond strength between one new and old composite usually requires increased surface roughness to promote mechanical interlocking since chemical bonding might not be adequate. similarly, the treatment of a laboratory fabricated resin composite restoration involves the same pro...

objective: despite great advances made in dental composite resins, their use is associated with some concerns regarding their mechanical properties such as their flexural strength. considering the introduction of different composite resins into the market, there is a need to compare their mechanical properties and particularly flexural strength. this study aimed to compare the flexural strength...

Aim: To compare marginal seal at tooth-material and material-material interfaces in the proximal box in combined amalgam/composite resin restorations. Methods: Mesio-occlusal-distal (MOD) cavities were prepared in 35 premolars and permanent molars with carbide bur. The distal proximal box was restored with amalgam (Permite, SDI) until reaching the height of pulpal floor. Dental tissues were etc...

AIM To compare the cusp fracture resistance of teeth restored with composite resins and two post systems. METHODOLOGY Eighty extracted single-rooted human maxillary premolars were randomly assigned to eight groups (n = 10). Group 1 (control) did not receive any preparation. From groups 2 to 8, the teeth were root filled and mesio-occluso-distal (MOD) cavities were prepared. Group 2 remained u...

introduction: the aim of this in vitro study was to compare polymicrobial microleakage of calcium enriched mixture (cem) cement, mineral trioxide aggregate (mta), amalgam, and composite resin as intra-orifice sealing materials. materials and methods: seventy single-rooted mandibular premolars were instrumented and obturated by cold lateral compaction technique. the teeth were randomly divided i...

The purpose of this study was to evaluate grinding efficiency in abutment teeth comprising both dentin and core composite resin in the axial plane. Grinding was performed over 5 runs at two loads (0.5 or 0.25 N) and two feed rates (1 or 2 mm/sec). The grinding surface was observed with a 3-D laser microscope. Tomographic images of the grinding surfaces captured perpendicular to the feed directi...

statement of the problem addition of metallic nano-particles to composite resins can change their water contact angle purpose the aim of this study was to evaluate the effect of addition of nano-particles of silver and zinc oxide to composite resins on their water contact angle materials and methods this in vitro study was performed on 60 composite resin samples. nano-silver and nano-zinc oxide...