SHARONLAY — A new onlay design for endodontically treated premolar

Root-canal-treated teeth are structurally compromised as a result of loss of tooth structure due to caries, iatrogenic cavity preparation, and dehydration. Given that a direct relationship exists between the amount of remaining tooth structure and the ability to resist occlusal forces, it is vital to provide a restoration allowing cuspal coverage as soon as possible following completion of the root canal treatment. A decision to provide a full crown or an onlay depends on the remaining tooth structure; if the cuspal width to length ratio is 1:2 or more, an onlay can be placed. When the ratio is less than 1:2, a full crown has to be planned. In single-rooted teeth requiring post-endodontic restoration cast post and core or a prefabricated post can provide resistance to fracture with comparable results. However, in case of premolars contradictory to the practice of providing only cuspal coverage through Onlays, it would in addition require cervical reinforcement also to counter horizontal forces acting in cervical region. A new onlay design SHARONLAY patented design with I.P. no 1956475 dated 27/04/2010 with a post extending into the radicular portion of the premolar providing the required reinforcement in a conservative manner and protecting it against both vertical and horizontal forces is proposed herewith.