Dentin thickness as a risk factor for vertical root fracture in endodontically treated teeth: a case-control study.

OBJECTIVES

This study evaluated factors associated with vertical root fracture in endodontically treated teeth, using a cone-beam computed tomography (CBCT) image database.

MATERIALS AND METHODS

The sample for this case-control study consisted of 81 CBCT scans of teeth with vertical root fracture (VRF) and 81 CBCT scans of non-fractured teeth, matched by age, sex, and tooth position. The analyzed variables included dentin thickness, an intraradicular post, an adjacent implant, and a missing adjacent tooth. Student's t test test was used to compare the quantitative variables. The chi-square test was used to compare the categorical variables. Logistic regression was performed to evaluate the association between the presence of VRF and the independent factors assessed.

RESULTS

The mean dentin thickness of fractured teeth was 1.3 mm, whereas that of non-fractured ones was 1.5 mm (p < 0.001). There was no difference between the fractured and non-fractured groups, regarding implant frequency or missing adjacent tooth (p > 0.05). There were a significantly larger number of teeth with posts in the fractured versus non-fractured group (p = 0.007). However, dentin thickness ≤ 1.3 mm was the only factor associated with VRF in the multiple regression model (OR = 3.60, 95%CI = 1.76-7.37).

CONCLUSIONS

Dentin thickness may influence the development of VRF. Dentin thickness ≤ 1.3 mm is associated with a greater likelihood of fracture than ≥ 1.4 mm.

CLINICAL RELEVANCE

This study suggests there may be a minimum amount of safe dentin thickness that should be preserved after endodontic instrumentation.