Incidence of pulp necrosis subsequent to pulp canal obliteration from trauma of permanent incisors.

Little long-term data are available on the frequency by which pulp canal obliteration (PCO) subsequent to trauma leads to pulp necrosis (PN). In this study, 82 concussed, subluxated, extruded, laterally luxated, and intruded permanent incisors presenting with PCO were followed for a period of 7 to 22 yr (mean 16 yr). At final clinical examination, 51% of the observed teeth responded normally to electric pulp testing (EPT). An additional 40% of the teeth although not responding to EPT were clinically and radiographically within normal limits. Yellow discoloration was a frequent finding. During the observation period, periapical bone lesions suggesting PN developed in seven teeth (8.5%). Twenty-yr pulp survival rate was 84%, as determined from life-table calculations. There was no higher frequency of PN in obliterated teeth subjected to caries, new trauma, orthodontic treatment, or complete crown coverage than intact teeth. Although the incidence of PN in teeth displaying PCO seems to increase over the course of time, prophylactic endodontic intervention on a routine basis does not seem justified.