Autogenous tooth transplantation is a simple technique that typically results in a satisfactory outcome. However, there are still many challenges, such as insufficient alveolar bone and tooth vitality. The aim of this study was to report two clinical cases of autogenous tooth transplantation with severe alveolar bone defects, one tooth with immature root development and one with mature root formation.
Clinical and radiographic data of the two cases were collected over three and twelve years.
The two cases of autogenous tooth transplantation demonstrated successful bone regeneration without using a bone graft. The gingiva regained their normal characteristics and the teeth maintained their vitality with both immature- and mature-rooted transplants surviving with almost complete pulp obliteration and without endodontic treatment through the follow-up period of twelve years.
Autogenous tooth transplantation in a severely insufficient alveolar ridge can be achieved based on standard success criteria. Furthermore, endodontic treatment might not always be necessary when the transplanted tooth has a completely formed root with a closed apex.
Autogenous tooth transplantation with alveolar bone defects demonstrated bone regeneration without using a bone graft.
A blood clot, which was intentionally created in our cases through the recipient site preparation, acts as a scaffold.
Periodontal ligament was preserved by removing bony wall to minimize trauma and by keeping in blood clot as a reservoir.
Endodontic treatment might not always be necessary when transplanted tooth has a completely formed root with a closed apex.
There are currently many treatment options available for replacing a missing tooth. Autogenous tooth transplantation (ATT) is a simple technique that is low-cost and results in positive outcomes. Its success rate has increased rapidly from 50% in the 1950’s to 94% in the 2000’s [ ] and the outcomes have become more predictable. ATT gives better results in terms of normal function, aesthetics, and regeneration based on the host cells and tissue availability, which can be achieved using a non-traumatic protocol.
Although ATT is an optimal method for tooth replacement when a donor tooth is available, there are still many challenges to achieving a satisfactory result. The most difficult cases present with an extremely insufficient alveolar bone ridge due to bony wall defects, which can be restored using bone grafting materials [ ]. Loss of tooth vitality following ATT is also a concern. Therefore, a tooth with a completely formed root requires only additional endodontic treatment that can be performed before or after transplantation [ , ]. Furthermore, achieving good stabilization of the transplanted tooth has been recommended using various techniques ranging from flexible fixation with nylon crossing over the occlusal area to more rigid fixation with orthodontic wire [ , , , ]. However, excessive surgical time and inflexible stabilization can result in adverse effects, such as ankylosis, insufficient periodontal regeneration, and lack of pulp revascularization [ ].
Here, we report two clinical cases with severe alveolar bone defects; one tooth with immature root development and another with complete root formation. A surgical procedure based on tissue engineering concepts was performed using non-rigid stabilization and without endodontic treatment. Periapical radiographs and cone-beam computational tomography (CBCT) were used to track the alveolar bone regeneration and periodontal attachment in parallel with clinical observation of the attached gingiva and tooth vitality.
Two cases of autogenous tooth transplantation are reported here with the approval of the Institutional Review Board of the Faculty of Dentistry/Faculty of Pharmacy, Mahidol University (COA. No. MU-DT/PY-IRB 2012/128. 2607) and in accordance with the Helsinki Declaration. Both patients were evaluated as previously described and determined to be ASA class I [ , ]. Additional inclusion criteria were non-pathological teeth, normal crown shape, and that the tooth was easy to manipulate. Information and risks of the procedure were explained to the patients and informed consent was obtained. Furthermore, the patients received oral hygiene instruction and full mouth scaling.
All ATT surgical procedures at the oral and maxillofacialsurgery clinic were performed similarly and divided into four phases, recipient site preparation, donor tooth harvesting, fixation, and follow-up period. The recipient site was prepared after tooth removal when there were no signs of inflammation at the extraction wound. The operation was performed under local anaesthesia; 2% mepivacaine with epinephrine 1:100,000 units. A mucoperiosteal flap was gently elevated at the recipient site buccally and lingually and was buccally extended to the lower edge of the alveolar bone as needed. Harvesting was carefully performed without contacting the root surface; and any bone that obstructed tooth placement at the recipient site was removed. Granulation tissue was removed and the supporting alveolar bone was reduced and contoured to fit the root shape of the donor tooth using a bur in a low-speed handpiece. During bone adjustment, the donor tooth was repeatedly inserted back into its socket and was immersed in blood until the recipient site was fully prepared. Finally, the donor tooth was placed in the blood clot in the prepared recipient site below the occlusal level to avoid excessive load during early wound healing. The mucoperiosteal flap was replaced above the cemento-enamel junction ( Fig. 1 ) and was stabilized using non-rigid stabilization by cross-suturing between the mesial and distal interdental papilla of the transplanted tooth using polyamide sutures (Ethicon ®, USA). 1000 mg amoxicillin and 400 mg ibruprofen were given preoperatively, and 500 mg amoxicillin every 6 h for 5 days plus 400 mg ibuprofen every 8 h as needed for pain were prescribed after the operation.
The follow-up period was 1, 3, and 7 days after the operation to evaluate the patient’s oral hygiene and remove the excess blood clot covering the occlusal surface of the transplanted tooth. The patients were instructed not to chew on the transplanted side for one month, and to then eat a soft diet for one week before gradually increasing to solid food. Furthermore, they received instructions on how to properly clean the transplanted tooth. Seven days post-operation, the sutures were removed and the tooth was supported by the granulation tissue. During every re-call visit after 3 months, the patients’ periodontium was examined, and pulp vitality was determined using an electric pulp test (EPT). Periapical radiographs and CBCT scans were taken immediately after transplantation and approximately 1, 3, 6, and 12 months post-operation. Subsequently, the patients’ attended a recall visit once a year.
The two cases received this standard protocol, with only minor differences performed depending on the bony defect severity.
A 16-year-old woman was referred to the oral and maxillofacial surgery clinic in April 2006 for ATT by her orthodontist due to second premolar aplasia and an accidentally lost first premolar on the left mandible ( Fig. 2 -a). The candidate donor tooth was the unerupted lower left third molar, which was undergoing root development, but was too large mesio-distally to fit in the recipient site ( Fig. 2 -e, f). The ATT was planned in parallel with orthodontic treatment.
Knife-shaped alveolar crests with thin buco-lingual width continuing to the basal bone level were found after the mucoperiosteal flaps were opened ( Fig. 2 -b, c, d). Thus, the recipient site could not be prepared using the standard protocol. The alveolar crest was adjusted to a saddle shape to support the furcation of the donor tooth. During tooth transplantation, we carefully harvested and placed the donor tooth at a 90° rotation on the saddle shaped bone, without bony wall support on the entire mesial and distal roots, thus, they were supported only by the mucoperiosteal flap ( Fig. 2 -b, c, d). Finally, the tooth was transplanted in buccoversion and 3 mm below the occlusal level ( Fig. 2 -d, g and Fig. 3 -a). The mucoperiosteal flap was sutured such that the flap margin was above the cemento-enamel junction (CEJ) of the transplanted tooth, and post-operative care instructions were given as described above.
At the 3-week post-operative follow-up the gingiva demonstrated normal soft tissue healing of the interdental papilla together with a healthy marginal gingiva and attached gingiva that was present at the three-year follow-up ( Fig. 3 -a-o). The severe tooth mobility post-transplantation was reduced to first-degree mobility at four months and normal mobility at six months when the sulcus depth recovered to the normal range (<3 mm). Similarly, the EPT was positive from six months and remained positive through 3 years when the pulp exhibited near complete obliteration radiographically ( Fig. 3 -d, h, l, p).
During the same period, the improved tooth stability was confirmed on periapical radiograph that showed increased trabeculation of the surrounded bone ( Fig. 3 -d, h) and the presence of the periodontal ligament space, lamina dura, and continued root formation ( Fig. 3 -l, p). Bone at the furcation formed that subsequently covered the buccal and lingual sides of the roots, and also extended to the basal area. Continued root formation was evident at six months and at three years in parallel with the gradual regeneration of the surrounding bone as shown in the CBCT images ( Fig. 4 ). Orthodontic force was applied to upright the transplanted tooth into the correct alignment and levelling for a year post-operatively until it was moved 8 mm lingually ( Fig. 3 -i-o and Fig. 4 -c, d).