Date of Graduation


Document Type


Degree Type



School of Dentistry


Not Listed

Committee Chair

Samuel Dorn

Committee Co-Chair

Mark Byron

Committee Member

Susan Morgan


Introduction: External cervical resorption (ECR) is a destructive type of external resorption that can be difficult to treat. ECR usually begins subgingival at the cementoenamel junction of teeth and continues apically and circumferentially. This substantial loss of tooth structure may make these teeth more prone to fracture and should be addressed when treatment planning teeth with ECR. The aim of this in vitro study was to evaluate the fracture resistance of treated and non-treated teeth with simulated ECR using two different treatment modalities.

Materials and Methods: Forty-eight extracted human permanent mandibular central incisors were selected. Teeth were randomly divided into four groups (n=12). Twelve teeth were assigned to the negative control no treatment group and the remaining 36 samples received standardized ECR cavities. Twelve of the teeth were not instrumented and were assigned as a positive control group. The remaining twenty-four teeth were instrumented and divided into two separate treatment modalities, a fiber post group and a gutta percha group. ECR cavities in the fiber post and gutta percha group were restored with a resin-modified glass ionomer material. Specimens were embedded in acrylic resin and subjected to fracture testing using a universal testing machine. The load (N) at failure was recorded for each specimen, and the data was statistically analyzed.

Results: The negative control group had the highest fracture resistance and differed significantly from the positive control, fiber post, and gutta percha group (P < 0.05). No significant difference was found between the positive control, fiber post, or gutta percha group (P > 0.05).

Conclusion: This in-vitro study concluded that teeth with simulated ECR were found to have a decreased resistance to fracture, which suggests they are weaker and more prone to fracture. When restoring teeth with ECR, the placement of a fiber post is not necessary, as it will not increase their fracture resistance.