Results after replantation of avulsed permanent teeth. III. Tooth loss and survival analysis.

Avulsed permanent teeth were replanted following immediate extraoral endodontic treatment by insertion of posts from a retrograde direction. Some teeth were rescued in a physiologic environment (tissue culture medium contained in a tooth rescue box), and in some cases antiresorptive-regenerative therapy (ART) was used. The aim of the study was to identify variables that influence the incidence of tooth loss and the survival of avulsed and replanted permanent incisors. Twenty-eight permanent teeth in 24 patients aged 7-17 years were investigated. In all teeth extraoral endodontic treatment by retrograde insertion of posts was performed. All nine teeth with functional healing (FH) were in situ. Of the 19 teeth with non-FH, seven were removed to allow transplantations. Two teeth were removed due to severe infrapositions. One tooth was lost following a new trauma. No tooth was lost due to acute infections. In descriptive statistics the incidence of tooth loss was significantly related to healing (P = 0.0098, Fisher's exact test), to treatment planning, i.e. consecutive replantation of premolars and primary canines (P = 0.0001, Fisher's exact test) and to immediate physiologic rescue (P = 0.0394). ART was related to tooth loss when tested in teeth with a compromised periodontal ligament (P = 0.0389). No influence could be found for the parameters maturity, age and all other factors. In a regression analysis treatment planning was the only factor left which had a significant influence (P = 0.0002). The estimated mean survival time (Kaplan-Meier analysis) for all teeth was 57.3 months. The survival was significantly reduced (P = 0.0002, log rank test) when consecutive transplantations were intended and performed. No influence could be found for maturity, age and all other factors. The different findings to previous studies can be explained by the prevention of complications related to conventional endodontic treatment approaches. Statistics have to be carefully interpreted due to case preselection which is determined by the treatment guidelines and actual treatment options of the individual treating dentist.