The effect of immediate controlled forces on periodontal healing of teeth replanted after short dry time in dogs

Abstract

The extra-alveolar dry period and storage medium in which a tooth is kept prior to replantation remain critical factors affecting the survival and repair potential of the periodontal ligament in avulsed teeth. When replantation is not immediate, replacement root resorption (RRR) is the most common complication. The aim of this histological study was to evaluate the effect of immediate controlled-orthodontic forces in periodontal healing of replanted teeth in a canine model. Sixty maxillary and mandibular premolar roots were endodontically treated in vivo and subsequently hemisected and extracted. Roots were replanted after an extraoral dry time of 20minutes and randomly assigned to two experimental groups: Group 1: root was stabilized with a flexible and passive bracket/stainless steel wire splint for 2weeks; Group 2: root was stabilized with a flexible bracket/NiTi wire splint activated with orthodontic elastics for 2weeks. After 4months, the dogs were euthanized, and all specimens were processed for histology and microscopically evaluated. The mean percentage of RRR for Group 2 was 3.17 compared with 12.13 in Group 1. Eighty-three percent of specimens from Group 2 exhibited similar healing to the negative control group, compared to 60.5% of the specimens from Group 1. No statistical difference was found in periodontal healing between experimental groups. Immediate application of mild and controlled orthodontic forces was not detrimental to the periodontal healing of teeth replanted after 20minutes extraoral dry time, although no significant improvement on periodontal healing was observed.