based on the book chapter by Michael K. McGuire Summary There is an extensive body of evidence relating to soft tissue keratinization and the mucogingival junction (MGJ). This chapter provides an overview of the subject, and revisits the anatomy of the tooth periodontium. The protocol it describes is a randomized trial that targets patients with two non-adjacent sites of one to four tooth spans and less than 2mm of keratinized gingiva. The pre-surgical phases include screening and baseline observations, and the procedure involves comparing an apically positioned flap plus vestibuloplasty (benchmark treatment) with a new therapy. The protocol describes preferred techniques for probing and taking punch biopsies, and specifies dimensions of the wound bed. The authors recommend removing existing keratinized gingiva from the mucosal flaps so that results with the gingival graft are more discernible. They give specific instructions on the method of taking clinical photos. Post-surgical evaluations take place over 6 months, and include patient-reports of postoperative pain and discomfort at the treatment and harvest sites, with inflammatory assessment by a scoring system and measures of apicocoronal width. Other practical recommendations include the use of probes that are calibrated for studies and a 3-mm biopsy punch for revealing the MGJ, as well as allowing a learning curve for surgical techniques, possible pilot patient procedures, carrying out batch surgeries and pre-study power calculations, and consulting a biostatistician. Open full-text PDF (1.4 MB)

Objectives: Severe injuries or biological dysfunction of the periodontal ligament may lead to ankylosis. Osseointegrated implant and ankylosed teeth are very similar, both with the potential for complete immobility. Ankylosis and osseointegration affect dentoalveolar development during growth, and lead to infraposition and aesthetic problems. Relocation of malpositioned ankylosed teeth or implants to correct positions requires surgery. The aim of this study was to evaluate the orthodontic bone-stretching procedure. Methods: A cohort of patients presented with implants in the wrong position (n = 4) or an ankylosed tooth in infraclusion (n = 14). Orthodontic treatment was conducted for dysmorphosis correction, excluding ankylosed teeth or implants. Before surgery, dental CTs were taken to evaluate the positions of adjacent teeth for surgical planning. Under local anesthesia, a full-thickness flap was reclined and two vertical deep corticotomies were performed using piezosurgery (Piezotome 2 SatelecRTM) on either side of the ankylosed tooth or implant. Then the two vertical cuts were connected by making a third cut, subapical to the apex. Immediately after the surgical procedure, orthodontic traction was applied and reactivated every two weeks. Calipers were used to take comparative measures with adjacent teeth during activation of the bone-stretching device. The quantity and speed of the movement were evaluated. At the end of the treatment, control cone-beam CT (CBCT) was performed, and MeshlabRTM software and movements in three dimensions were assessed by CBCT merging. Results: After a period of 3–9 months, each ankylosed tooth or implant had been moved. At the end of the treatment, they were correctly repositioned. In one case in which root resorptions were important, the movement was stopped by a tooth fracture. The analysis showed that the movement began after a minimal period of three weeks and continued until the end of the traction. The duration of treatment depended more on the distance between the incisal edge and the occlusal plane than on traction strength. Repositioning with vertical movement was more difficult than with palatal or vestibular movements and may require second surgery. The control did not demonstrate periodontal pathology after orthodontic bone-stretching. The control CBCT showed tooth or implant repositioning occurred with no problems. Osseointegration was stable for implants. CBCT merging to show bone movement revealed that the implant or ankylosed tooth moved with the neighbouring bone at the same time and in the same direction. The bone-stretching movement led to vertical bone augmentation. While the maxilla developed in a vertical direction, the ankylosed teeth remained more or less in infraocclusion. The individual growth pattern and progression of infraposition varied with age and sex of the patient. Slight over-treatment might compensate for this. Conclusion: The orthodontic bone-stretching technique seems to be viable for relocating ankylosed teeth and implants from a wrong position, but orthodontic preparation is essential and is associated with adequate soft tissue management. Bone-stretching movement led to a vertical bone augmentation. The results with ankylosed teeth and implants may not be stable over time and continuous growth of the patient must be considered when planning treatment. In the future, this technique may enable relocalisation of implants in the wrong position, however more long-term prospective clinical trials are needed to confirm its effectiveness.