Post-treatment coronal hermetic seal of the root canal opening prevents the food or saliva which assist to achieve successful endodontic treatment. Gutta-percha is filled in the inner canal, that is, from cervical third to apical third. Gutta-percha does not provide the hermetic seal because it does not bound with dentine walls. Various new restorative materials have been developed in the last 6–7 decade but drawback related to the polymerization shrinkage of the composite resin remains a clinical problem. In general, dental composites having volumetric shrinkage of the material depends on its formulation and curing conditions. In this article, the effect of this polymerization shrinkage on the tooth structure has been studied.