COMPARATIVE EVALUATION OF MARGINAL LEAKAGE AMONG TOOTH COLORED DIRECT RESTORATIVE MATERIALS (CENTION N, ACTIVA BIOACTIVE RESTORATIVE AND NANOFILL COMPOSITE) IN CLASS II RESTORATIONS USING STEREOMICROSCOPE: AN IN-VITRO STUDY.

Abstract

Composite restorations occupied commendable place among direct restorative materials¹ .The esthetic properties and bonding to the tooth structure and command setting are the unique features of composite restorations^2,3.The other advantages of composite’s availability of desired consistencies based on shape, size and volume of the filler particles, such as flowable, packable, bulk filled resins also available site specific demand subjected to withstand various levels of occlusal loads. Based on curing type, chemically cured, light cured and dual cured systems which made possible to control setting time as well as minimise shrinkage stresses and also duel and chemical cured resins can be restored where curing light inaccessable⁴.

Commercial dentin adhesives are usually provided by the manufacturers for corresponding composite materials because interchanging of adhesives can produce incompatibility, which may impair the marginal seal and the performance of the restoration. This incompatibility may also account for the conflicting results of the in vitro marginal seal obtained with some dentin bonding agents. Consistent, long-lasting, nonleaking margins have not yet been achieved in composite resin restorations that are finished in dentin. There is a need for an effective, durable dentin adhesive agent. Even though the composite restorations having a wide range of merits, equally demerits also evident, such as least wear resistance, polymerization shrinkage and higher thermal expansion ultimately responsible for marginal leakage, postoperative discomfort due to sensitivity, secondary caries and finally clinical failure of the restoration^5,6 .

Larry Hench in 1969 was the first to use the term bioactive materials in describing a new material for bone reconstruction that could be able to form a bond to body tissues. The early concept of bioactivity was limited to a biomaterial that elicits a specific biological response at the material tissue interface which results in the formation of a bond between them. Till now, the concept of bioactive materials had extremelyexpanded . Bioactivity arises when a material could be elicits combination of an intracellular and extracellular response through its interface. These materials are used mainly for repair, reconstruction and regeneration of dental insults. For example, glass ionomer has been described as bioactive material due to their ability to remineralize of tooth structure, in addition to continuous dynamic release of fluoride which delay the secondary caries around the restoration margins⁷.