Prevalence of and Factors Associated With Vertical Root Fracture in a Japanese Population: An Observational Study on Teeth With Isolated Periodontal Probing Depth

Previous studies on the prevalence of vertical root fractures (VRFs) were based on extracted teeth, or teeth referred for apical surgery. This study examined teeth with an isolated periodontal probing depth (PD) as an indicator of VRF. The primary aim of this study was to investigate the prevalence of vertical root fracture (VRF) and non-VRF among teeth with an isolated probing depth (PD) ≥ 5 mm. The secondary aim was to assess factors associated with VRF by comparing the teeth with and without VRF in the Japanese population. A total of 288 teeth with an isolated PD ≥ 5 mm were grouped pathologically into 8 groups comprising VRF and non-VRF conditions. A descriptive analysis for age, sex, tooth type, endodontically treated teeth (ETT) versus non-ETT, proximal contacts, PD (depth), PD (broadness and location), restoration type, and presence of a post was performed. Moreover, the associations between these factors and VRFs were investigated using the Chi-square test. The prevalence of VRF was 32%. Lower first molars were the most common tooth type in both VRF (31.5%) and non-VRF groups (29.7%), while premolars were exclusively frequent in VRF (30.2%) and not frequent in non-VRF (7.8%). Narrow buccolingual PD was common in VRF (78.1%) whereas wide PD was frequent in non-VRF (67.1%). ETT, narrow buccolingual PD, tooth type (premolars), restoration type (crown), and the presence of a post showed significant associations with VRF (P ≤ .001). VRFs may be more prevalent in ETT among the Japanese. Careful assessment is necessary to differentiate VRFs from other conditions when the lower first molars show an isolated PD ≥ 5 mm. When an endodontically treated premolar with a post shows a narrow buccolingual PD, the probability of a VRF may be greater than in other tooth types.