Periodontal healing following avulsion and replantation of teeth: a multi-centre randomized controlled trial to compare two root canal medicaments Avulsion is one of the most severe dento-alveolar injuries. This injury accounts for between 0.5% and 3% of dento-alveolar trauma to permanent teeth (1) but also carries one of the poorest outcomes for dento- alveolar trauma with 73–96% of replanted teeth being lost prematurely (1). The damage to the periodontal ligament at the time of injury, the condition of a tooth’s subsequent storage and the interval prior to replantation, all profoundly influence prognosis (2–4). The evidence to support different treatment interventions provided by clinicians is limited. A recent Cochrane review (5) identified three randomized controlled trials that were eligible for inclusion. Two of the studies were at high risk, with the third categorized as moderate risk of bias. Thus, the evidence to support most treatment interven- tions as advised by different guidelines (6, 7) is based upon human case series, which are frequently retrospec- tive in nature or based on animal studies. Consequently, there is a clear need to demonstrate the effectiveness of different interventions using study designs that are of low risk of bias and are carried out in humans. As avulsion injuries present relatively infrequently even to specialist centres (2, 3), a multi-centre design would be required. The Cochrane review (5) was unable to identify any multi-centre randomized controlled trials (m-cRCT) teeth. Medicaments to promote periodontal healing follow- ing avulsion and replantation have been studied exten- sively in animal models. Topical medicaments applied to the tooth prior to replantation have the advantage of reduced systemic uptake and less reliance on pharmoki- netics to ensure adequate concentrations are delivered to the socket and associated tooth (8, 9). One of the major problems with topical medicaments is the retention of medication in the socket and prevention of ‘wash-out’ during replantation and subsequent exudation. One possible solution is to place it inside the root canal. This space following endodontic treatment is avascular, and consequently, any medicament will remain in-situ to exert its effect. The root canal has the added benefit of Dental Traumatology 2012; 28: 55–64; doi: 10.1111/j.1600-9657.2011.01053.x Ó 2011 John Wiley & Sons A/S 55 Peter F. Day 1 , Terry A. Gregg 2 , Paul Ashley 3 , Richard R. Welbury 4 , Ben O. Cole 5 , Alec S. High 1 , Monty S. Duggal 1 1 Leeds Dental Institute, Leeds; 2 Belfast Children’s Hospital, Belfast; 3 Eastman Dental Institute, London; 4 Glasgow Dental Hospital, Glasgow; 5 Newcastle Dental Hospital, Newcastle upon Tyne, UK Correspondence to: Peter F. Day, Department of Paediatric Dentistry, Leeds Dental Institute, Leeds LS2 9JT, UK Tel.: 0113 3436139 Fax: 0113 3436140 e-mail: p.f.day@leeds.ac.uk Accepted 21 July, 2011 Abstract – Background: Non-setting calcium hydroxide (Ultracal XS Ò ) is recommended by the International Association of Dental Traumatology as the initial medicament following avulsion and replantation for mature teeth. There is experimental evidence to suggest Ledermix Ò , placed as an alternative inter-visit dressing may improve periodontal healing. Aim: This study investi- gated, using a multi-centre randomized controlled trial, the effect of two root canal medicaments, Ledermix Ò and Ultracal XS Ò , on periodontal healing of avulsed and replanted teeth. Material and methods: Children were recruited if they fulfilled all inclusion criteria. Treatment followed a standardized protocol. Assessment of periodontal healing or ankylosis was made clinically and radiographically by an experienced, ‘blinded’, clinician at 12 months. Results: Over 200 patients were assessed for eligibility at five centres. Twenty- nine patients were eligible for inclusion. Final analysis involved 22 patients with 27 teeth. Ankylosis was detected in four of the 12 teeth in the Ledermix Ò group and nine of 15 in the Ultracal XS Ò group. No significant difference between medicaments was found in the proportion of teeth or patients showing periodontal healing. Discussion: There was no significant difference in peri- odontal healing between the two medicaments at either a tooth or patient level. The numbers recruited fell short of an estimated power calculation. For patients meeting the inclusion criteria and completing the trial, periodontal healing was seen in 52% of teeth at the 12-month assessment between both groups. The only factor found to significantly influence the periodontal outcome was dry time.