الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The improvement of existing dental material and the development of new material for use in dentistry is an expanding field in the health care sector.
Various composite materials are available today for direct restorative techniques. The most well-known materials are the nanohybrid composites. The integrity and durability of the marginal seal is an important factor in the longevity of adhesive dental restorative materials. The amount of microleakage is governed by marginal adaptation of the restorative material to the tooth. New materials were introduced for effective marginal seal in order to prevent microleakage.
The present in vitro study was conducted to compare the effect of self-etch adhesive system with total-etch adhesive system on microleakage of class V cavities restored by universal nano-hybrid composite resin in primary teeth.
The study was carried out on fifty sound primary teeth exfoliated or extracted for orthodontic purposes. The exposed pulp chamber or root apices were sealed and covered with sticky wax. Each tooth was embedded in an acrylic block, with the buccal surface facing outwards. Standardized class V cavities were prepared. Following cavity preparation, the teeth were divided randomly into two equal groups according to the type of adhesive systems tested, into group I and group II.
In group I twenty five teeth were restored by total-etch adhesive system (Solobond M) and composite resin (Grandio®). In group II Twenty five teeth were restored by self-etch adhesive system (future bond ® DC) and composite resin (Grandio®).
After restoration all samples were stored in distilled water at 37°C inside an incubator unit for 24 hours to be prepared for thermocycling.
They were thermocycled in a water bath for 1000 cycles between 5°C and 55°C, with a dwell time of 15 seconds using thermocycling machine. The exposed tooth surfaces were covered with three layers of nail polish except the surface of restoration and a surrounding 1mm area. All specimens were immersed in 0.5% basic fuchsine dye at 37C˚ for 24 hours. Teeth were removed from dye solution and washed under running water for half an hour. The teeth were sectioned buccolingually through the center of the restoration using a water-cooled diamond disc. The sectioning resulted in two approximately equal parts, which where both analyzed for microleakage using stereomicroscope ×60 magnifications.
The result of the present study showed that, occlusal leakage in group I was significantly better than group II. Gingival margins of restorations exhibited more microleakage than occlusal margins in both groups. When adding microleakage scores of both gingival and occlusal represent no statistical significance difference was detected between both groups.