Cross-sectional study of posterior tooth root fractures in 2015 and 2019 in a Chinese population

Objectives This study aimed to compare posterior tooth root fractures in endodontically treated teeth versus nonendodontically treated teeth in the Chinese population. Materials and methods We investigated 500 root fractured posterior teeth in 461 Chinese patients. The clinical information (age, sex of patients, tooth type) were recorded. The fractured teeth were divided into endodontically treated root fractured (ETRF) teeth and nonendodontically treated root fractured (NETRF) teeth. The morphology of the fractured root (circular, oval, other), the orientation of fracture lines (vertical and non-vertical), the restorations performed (crown, filling, non-filling), and the position of the teeth in the dental arch (normal, misaligned) were evaluated based on cone-beam computed tomography images. These data were compared between 2015 and 2019. ETRF% was calculated as ETRF/ETRF + NETRF. Vertical% was calculated as vertical/vertical + non-vertical. Results There were 177 ETRF teeth and 323 NETRF teeth in this population. The total ETRF% was 29.3% in 2015 and 37.6% in 2019 ( P = 0.087). The proportion of vertical root fracture in the ETRF group increased significantly in 2019 compared with that in 2015 (46.2% vs . 80.2%, P = 0.000). The ETRF% in female patients increased by 16.8%, but increased by only 1.2% in male patients in 2019 compared with that in 2015. The ETRF% of mandibular and maxillary premolars increased by 48.5% and 29.3%, respectively. The proportion of crown restoration increased by 2.4% in 2019 compared with that in 2015 in the ETRF group. Conclusions The proportion of NETRF teeth and non-vertical root fractures in posterior teeth is high in this Chinese population. The number of vertical root fractures in endodontically treated teeth increased significantly from 2015 to 2019. Clinical relevance More attention should be paid to endodontic treatment factors in the occurrence of root fractures, especially as female patients and premolars are more susceptible.