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...

objectives: to assess the effect of lactic acid (la) on microleakage of silorane-based composite restorations and methacrylate-based composites with self-etch and etch-and-rinse bonding systems. materials and methods: class v cavities were prepared in 120 extracted human teeth, divided into four groups and restored as follows: 1. silorane-based composite+p90 adhesive system (p90); 2. filtek z25...

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...

Abstract Background and Aim: One of the major problems with resin composite restorations is the weakness of bonding between the new and aged composites. Since appropriate micromechanical retention is necessary for the repair of aged resin composite restorations, the level of surface roughness after sandblasting can be influential in this regard. Considering the diverse composition of avail...

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...

background and aim: present study was designed to compare the bonding strength of resin-modified glass ionomer (rmgi) and composite resin to mineral trioxide aggregate (mta), mta mixed with na2hpo4 (namta), and calcium-enriched mixture (cem). materials and methods: thirty specimens of each cem, namta, and mta were prepared. composite and rmgi restorations were then placed on the samples (15 sam...