Abstract – Background: The reported risk of pulp necrosis (PN) is generally low in teeth with subluxation injuries. A concomitant crown fracture may increase the risk of PN in such teeth.
Aim: To analyse the influence of a concomitant trauma-related infraction, enamel-, enamel–dentin- or enamel–dentin–pulp fracture on the risk of PN in permanent teeth with subluxation injury.
Material and Methods: The study included 404 permanent incisors with subluxation injury from 289 patients (188 male, 101 female). Of these teeth, 137 had also suffered a concomitant crown fracture. All the teeth were examined and treated according to a standardized protocol.
Statistical Analysis: The risk of PN was analysed separately for teeth with immature and mature root development by the Kaplan–Meier method, the log-rank test and Cox regression analysis. The level of significance was set at 5%. Risk factors included in the analysis were gender, patient age, crown fracture type, mobility and response to an electric pulp test (EPT) at the initial examination.
Results: Teeth with immature root development: The risk of PN was increased in teeth with a concomitant enamel fracture (log-rank test: P = 0.002), enamel–dentin fracture (log-rank test: P < 0.0001), enamel–dentin–pulp fracture (log-rank test: P < 0.0001) and in teeth with no response to EPT at the initial examination [hazard ratio: 21 (95% confidence interval, CI: 2.5–172.5), P = 0.005]. Teeth with mature root development: the risk of PN was increased in teeth with an enamel–dentin fracture [hazard ratio: 12.2 (95% CI: 5.0–29.8), P < 0.0001], infraction [hazard ratio: 5.1 (95% CI: 1.2–21.4) P = 0.04] and in teeth with no response to EPT at the initial examination [hazard ratio: 8 (95% CI: 3.3–19.5), P < 0.0001].
Conclusion: A concomitant crown fracture and no response to EPT at the initial examination may be used to identify teeth at increased risk of PN following subluxation injury.