SHARONLAY - A new onlay design for endodontically treated premolar

Stress distribution in endodontically treated single-rooted premolars restored with everstick post and sharonlay: A finite element analysis

Background

The objective of the study is to compare stress distribution in a tooth restored with everstick post and sharonlay by means of three-dimensional finite element analysis (3D-FEA).

Materials and Methods

An experimental original study was carried out in which two 3D-FEA models were constructed: (1) tooth restored with everstick post and metal ceramic crown and (2) tooth restored with sharonlay. The material properties were assigned and a force of 100N, 200N, 300N, and 400N was applied to the centric stop of the occlusal surface in centric occlusion at a 45° inclination in a linguolabial direction to the long axis of the tooth. Analysis was run and the stress distribution pattern was studied. As all stress distribution analysis was performed with the Ansys 11.0 software (Inventor AutoCAD 2010; Autodesk) program, the significance of P value or tests for statistical analysis was considered.

Results

Sharonlay showed more total deformation, larger stress, and strain concentration than that of everstick post.

Conclusion

Tooth restored with sharonlay showed greater chances of deformation than everstick post. It also showed maximum strain concentration near the apical portion of the remaining tooth structure and more stress in the cervical third of the postsystem than everstick post.

Fracture resistance of endodontically treated single rooted premolars restored with Sharonlay: An in vitro study

AIMS

The aim of this study is to compare in vitro the fracture resistance of the endodontically treated tooth restored with a novel design Sharonlay, with the two component restorative method, i.e., post with separate onlay, and onlay without post.

SUBJECTS AND METHODS

45 single-rooted mandibular second premolars were taken, and root canal treatment was performed. Teeth were then randomly divided into three groups (n = 15) based on the type of restoration given: Group I - metal onlay with cast post extension (Sharonlay), Group II - metal onlay with prefabricated metal post (Mani post system), Group III - metal onlay over endodontically treated tooth obturated with Gutta-percha (control group). Fracture resistance was checked using the Instron universal testing machine and the fracture patterns were analyzed.

RESULTS

According to the values recorded, Group I showed maximum mean fracture resistance followed by Groups II and III. Statistically significant difference was found between Groups I and II and Groups I and III and statistically significant difference was found between Groups II and III.

CONCLUSION

A single unit component Sharonlay, gives higher fracture resistance to a premolar as compared to (a) metal onlay with prefabricated metal post and (b) metal onlay over endodontically treated tooth.