BIOMIMETIC DENTISTRY AND IMMEDIATE DENTIN SEALING
A full coverage crown preparation remove approximately 72-75% of tooth structure whereas preparations for overlay or onlay restorations removes only 32 – 47 % (Weber AR, Yilmas B 2021). Based on the current scientific evidence, overlay restoration should be considered as the treatment of first choice for posterior rehabilitation. They present as a biomimetic alternative to the conventional crown, they work in harmony with natural bio mechanics of the tooth and maximize the fracture resistance of ceramic materials, due to preparation design and bonding techniques. In biomimetic dentistry, the compression dome refers to the tooth enamel structure above the line of maximum contour (tooth equator) that receives primarily compressive forces. The tooth structure from the maximum contour line to the cemento - enamel junction (approx.2mm) that supports the compression dome is referred to as the bio- rim. This region of the tooth bears the greatest amount of tensile forces during mastication.
In conventional procedures, sealing of the dentinal tubules takes place at the bonding stage of the final restorations (Delayed dentin sealing). Thus during provisionalization, exposed dentin leaves a potential pathway for bacterial infiltration. Immediate dentin sealing (IDS) technique rests upon four fundamental principles. First, only fresh-cut, contaminant-free dentin provides the optimum substrate for bonding. Second, if the Dentin bonding agent ( DBA) and overlaying composite are light-cured together, the hybrid layer may collapse due to the pressure from the composite or restoration placement. Thus, precuring the DBA results in a better bond strength. Third, IDS and delayed restoration placement permit maturation of the dentin bond in an environment free of occlusal forces and overlaying composite shrinkage. Fourth, IDS reduces fluid and bacterial penetration. The clinical advantages include (i) patient comfort during provisionalization, less need for anesthesia at the cementation appointment, and reduced post-cementation sensitivity; (ii) increased bond strength and retention, especially for tapered teeth with short clinical crowns and minimum removal of tooth tissue (iii) independent treatment and conditioning of dentin and enamel that maximizes the overall performance of both tissues according to their individual characteristics.
Dr Binu P, MDS, Assistant Professor, Dept. of Conservative Dentistry and Endodontics,
Govt. Dental College, Alappuzha.