الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The improvement of existing dental materials and the development of new materials for use in dentistry is an expanding field in the health care sector. These new materials have been raised for efficient marginal sealing ability and to prevent microleakage. Glass ionomer cement used in dentistry was initially limited by its slow setting time and lack of strength. However, modern formulations of the material have yielded materials with properties that are clinically useful in dentistry.
The development of conventional glass ionomer cement to resin modified GIC have produced materials with superior properties. However, their improvements are insufficient to compete in such high stress bearing areas as class I. Recently, glass carbomer cement as nano-filled GIC has been introduced with claims of improved physical properties.
The present study was conducted to evaluate the microleakage of glass Carbomer Cement with and without protective surface coating in class I primary molars in comparison to conventional glass ionomer cement.
The study was carried out on forty sound exfoliated or extracted for orthodontic purpose primary molars. Standardized class I cavities were prepared. Following cavity preparation, the specimens were conditioned with 20% polyacrylic acid gel. The teeth were divided into two main groups according to the type of restorative materials tested, into group A and group B of twenty teeth each, then they were further, sub-divided into four equal sub-groups (n=10). Sub-group A1 were restored with glass carbomer cement with protective surface coating, sub-group A2 were restored with glass carbomer cement without protective surface coating and sub-group B1 were restored with conventional glass ionomer with protective surface coating and sub- group B2 were restored with conventional glass ionomer without protective surface coating.
All teeth were restored with the appropriate restorative materials according to the manufacturer’s instructions, after restoration the teeth were stored in distilled water at 37° C inside an incubator unit for 24 hours.
They were thermocycled in a water bath for 1000 cycles alternating between 5°C and 55°C with a dwell time 30 seconds using the thermocycling machine. The pulp chamber, root apices and furcations were sealed with acrylic resin and sticky wax, teeth surfaces were coated with three layers of nail polish except the surface of restorations and the surrounding 1 mm. The teeth were immersed in 2% methylene blue solution for 24 hours, and then they were sectioned mesiodistally using a diamond saw through the center of the restoration. Each tooth produced two specimens and the extent of dye penetration was detected using a light stereomicroscope x20 magnification.
The results of the present study showed that glass carbomer cement with protective surface coat exhibited lower mean microleakage scores than glass carbomer cement without coat, indicating better sealing ability, while when comparing the two sub-groups of conventional GIC there was no statistically significant difference between them. Moreover, when comparing the four studied sub-groups there were statistically significant differences between them, with glass carbomer cement with protective surface coat showed the lowest mean microleakage scores, while glass carbomer cement without protective surface coat showed the highest mean microleakage scores.
Based on the result of the present study, glass carbomer cement with protective surface coat exhibited the highest sealing ability in class I primary molars.