microleakage in class ii composite restorations ... - ePrints@USM

CHAPTER TWOLITERATURE REVIEW2.1 Microleakage2.1.1 Introduction and DefinitionThe integrity and durability of the marginal seal has always been of prime concern inthe investigation of dental restorative materials performance. One of the key functionsof a dental restoration is to seal the exposed dentin from the oral environment, toprevent pulpal damage and further decay. Therefore, the microleakage at the toothrestorativeinterface is a major concern influencing the clinical longevity of compositeresin restorations (Gwinnett et al., 1995).The marginal integrity of the tooth and restoration interface is dependent uponseveral factors. It is dependent upon type of restorative material, the physical propertiesof the material, interactions between materials, physical properties of the tissueinterface, and the interaction of the oral environment (Rossomando and Wendt, 1995)The clinical symptoms associated with the occurrence of microleakage arebreakdown and discoloration of margins, secondary caries, increase in postoperativesensitivity, pulpal pathology, and reduction in the longevity of the restoration(Peutzfeldt, 2000).Leakage of water and other products can occur along the interface through voidscreated during insertion or function. Based upon the size of these voids, two types ofleakage can be distinguished:Microleakage: occurs when large voids are present causing water, large molecules,and even bacteria to migrate along the restoration. Microleakage is defined as the7