Combination injuries 2. The risk of pulp necrosis in permanent teeth with subluxation injuries and concomitant crown fractures

Abstract

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. 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. 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. 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. 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]. 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.