Assessment of Microleakage in Endodontically Treated Teeth Restored with Different Core Build-Up Materials

Abstract

In endodontically treated teeth, there are special treatment and restoration problems: coronal tooth structure loss, biomechanical changes, and a coronal seal. The selection of the core build-up material is critical in the restoration of tooth shape and the restoration of tooth functionality and the prevention of coronal micro leakages, which may jeopardize endodontic success. A synthesis of laboratory and translational findings involving commonly used core build-up materials such as resin composites, glass ionomer cements (GICs) and resin-modified GICs (RMGICs), amalgam, bulk-fill resins, and newer bioactive/core materials is proposed, with particular emphasis placed on the sealing ability, mechanisms that influence microleakage, and the methodological heterogeneity that make the comparison of these materials difficult. A summary of the most commonly used microleakage testing modalities (dye penetration, fluid filtration, bacterial leakage models, and micro-computed tomography), is provided including how aging conditions (thermocycling, mechanical loading) affect the results, and the interplay between adhesive strategy, preparation configuration (presence/absence of posts, ferrule, remaining tooth structure), and material properties (polymerization shrinkage, modulus, chemical adhesion) in predicting the integrity of coronal seals. Even though most in vitro findings predict that well bonded resin-based build-ups and current bioactive materials have the tendency to report positive immediate sealing, long-term microleakage resistance has been highly contingent on adhesive protocol, incremental method, cyclic fatigue and hydrolytic degradation resistance which differ widely across studies. RMGICs and traditional GICs have continuous fluoride release and chemical adhesion which can be useful in certain clinical applications, whereas their reduced mechanical properties can restrict usage in high drive cases only as core materials. Finally practical suggestions are made about the choice of material and standardization of laboratory tests with defined areas of priorities in the future to establish in vivo and standardized in vitro studies to define the clinical applicability of laboratory measures of microleakage.