Microleakage in Composite Resin Restoration- A Review Article.

ABSTRACT

The most important feature that a material must have is sufficient, long term sealing of the restorative margins. No restorative material developed to date is completely adhesive to the tooth structure. Every restorative material allows some degree of passage of fluids and micronutrients through it. It is termed as Leakage. By definition Micro leakage is “the clinically undetectable passage of bacteria, fluids, molecules or ions between a cavity wall and the restorative material”. It is the flow of a substance into a defect at the interface of restoration and tooth margin. Marginal leakage around restorative margins has been a concern with various clinical conditions. It includes quickening of the breakdown and dissolution of restorative materials. Marginal staining leads to collapse of margins, compromise in aesthetics and with time the need to substitute the restoration. Microleakage depends on several variables like dimensional change of restorative material mainly because of thermal contraction, polymerisation shrinkage, water sorption, mechanical stresses and dimensional changes of tooth. Almost all microleakage studies suggested that the majority of the materials accessible currently leak meaning that they allow penetration of dyes, radioisotopes, or bacteria. Microleakage can be calculated by various in vitro methods with or without thermocycling like staining, SEM, chemical agents, neutron activation analysis, ionization, autoradiography, radioisotope, and reversible radioactive adsorption. Reducing the marginal leakage and enhancing the marginal adaptation involves various factors like choice or combinations of materials, use of cavity liner or base, cavity design or configuration factor changes, acid etching and bonding, technique of restoration placement, direct or indirect techniques, sealing the marginal gaps, and different curing strategies. This article describes in depth the knowledge about various aspects of leakage such as sequelae and causes of microleakage, methods of detection of microleakage in vitro as well as clinically, and the measures taken to reduce or decrease the microleakage when restoring tooth with resin-based restorations.