Prevalence of vertical root fractures in teeth planned for apical surgery. A retrospective cohort study

Aim: To evaluate retrospectively the prevalence of vertical root fractures (VRFs) in a cohort of patients during apical surgery and the factors possibly associated with VRF. Methodology: The sample consisted of 944 root filled teeth belonging to 768 patients (49.3% males and 50.7% females; mean age 43.5 ± 11.2 years, range 22–68 years), consecutively referred for endodontic surgery over a six-year period. All patients underwent a clinical assessment of their signs and symptoms. Periapical radiographs of teeth that were candidates for endodontic surgery were taken. Sixty-eight teeth with VRF were identified. Vertical root fractures were identified in pre-surgical screenings in 32 cases (47.1%), and these did not undergo surgery. Another 36 cases of VRF were noted during the intervention for root-end resection. The influence of posts, post type, tooth type, periodontal probing defects, spontaneous pain, sinus tract and follow-up duration was assessed using a logistic regression analysis. Results: Vertical root fractures occurred significantly more frequently (P < 0.001) when a post was present (61 VRF out of 377 teeth with post, prevalence 16.2%) than in teeth without a post (1.2%). Threaded posts and cast posts were significantly more involved in VRF than fibre, silica or carbide posts (P < 0.001). Most fractures (80.9%) occurred 1–5 years after root canal treatment. Sinus tracts, probing defects and spontaneous pain were significantly more associated with VRF cases than with nonfractured teeth. Conclusions: In the present group of teeth, the major risk for VRF was represented by posts retained by actively engaging the canal via mechanical design (thread) or by frictional fit (cast).