The Effects of Rapid Periodontal Distraction on Tooth Vitality and Bone Quality/Quantity: A Split-Mouth Experimental Design.

Abstract

Objectives: Periodontal distraction (PD) osteogenesis is a minimally invasive technique capable of rapidly moving uniradicular teeth, thereby shortening orthodontic treatment time. This study aimed to determine whether: (1) PD-induced tooth movement affects tooth vitality and (2) the regenerated bone meets restorative standards for implant placement.

Materials and methods: In six dogs, the maxillary 2nd premolars on the experimental side were extracted, the mesial inter-radicular bone was removed to within 1 mm of the 1st premolar, and an intraoral distraction device was bonded. The contralateral side served as a negative control. After a 5-7 day latency period, the 1st premolars were distracted distally at 1 mm/day for 6 days, followed by a 3-week consolidation period. Tooth vitality was assessed with Laser Doppler Flowmetry (LDF) and histological analysis; bone quality and quantity were evaluated by μCT.

Results: Cast and intraoral measurements showed 4.7-4.8 mm of tooth movement at a rate of 0.8 mm/day. LDF recordings displayed pulsatile signals synchronized with each dog's heartbeat, indicating pulpal vitality, which was confirmed histologically by: (1) red blood cells in the pulp, (2) odontoblasts at the pulp periphery expressing Osterix, (3) rich vasculature revealed by GS-IB4 staining, and (4) similar blood vessel density between control and experimental sides. μCT analyses revealed slightly less dense, less mature bone mesial to the 1st premolar, but with complete or near-complete vertical and buccolingual fill. Mild root resorption was observed, with some resorptive lacunae, particularly on lingual surfaces.

Conclusions: PD can be performed at rates faster than previously reported without short-term adverse effects on tooth vitality or root integrity. Movement at 0.8 mm/day may substantially reduce treatment time in crowded, extraction cases. Additionally, PD offers a novel means to generate bone that may be suitable for implant placement in patients with congenitally missing teeth or partial edentulism.