Autotransplantation.

Autogenous tooth transplantation refers to the repositioning of autogenous teeth in another tooth extraction site or a surgically formed recipient site to replace missing teeth due to congenital deformity, grossly decayed carious teeth, mobile teeth due to periodontal disease, teeth lost due to trauma, endodontic failure or any other reason when a suitable donor tooth is available. This is a case report of autotransplantation of impacted #38 with complete root formation into the extraction site of grossly decayed, unrestorable #37 with 18 months follow-up showing excellent periapical healing and tooth stability. In autogenous tooth transplantation, even if the donor's tooth has complete root formation, a high success rate can be achieved if the cases are selected and treated properly. Chances of root resorption are there because of necrotic pulp and periodontal irritation during manipulation. However, autogenous tooth transplantation should always be considered as a good treatment modality in feasible cases.

INTRODUCTION

Tooth transplantation is the surgical repositioning of a tooth from one site to another. It is classified into autogenous, homogenous and heterogeneous transplantation. In autogenous transplantation, the tooth from one socket is inserted into another socket in the same person. In homogenous transplantation, the donor and recipient are of same species, and if the donor and the recipient are of different species, then it is called heterogeneous transplantation.[1]

Autotransplantation refers to the repositioning of an autogenous erupted or unerupted tooth from one site to another in the same individual.[2] Review of dental literature shows that one of the first descriptions of autogenic transplantation of teeth was given by a Swedish Dental Surgeon Vidman far back in 1915.[3] Impacted maxillary canines were the teeth traditionally selected for transplantation as they played a key role in dentofacial esthetics. Premolars and mandibular third molar teeth were also successfully transplanted.

Autotransplantation is indicated in traumatic tooth loss, tumors, congenitally missing teeth, teeth with bad prognosis and in case of developmental anomalies of teeth.[4] This procedure is cost effective and also results in better functional adaptation and preservation of alveolar ridge.[5] The success rate of autotransplantation varies from 74% to 100%, respectively.[6] Autotransplantation is contra-indicated in patients with cardiac anomalies, poor oral hygiene, lack of self-motivation and insufficient alveolar bone support.[5]

Autotransplantation has an important role in the replacement of missing teeth of young patients due to the contraindication of osseointegrated implants for them. The auto transplanted tooth has the capacity for the preservation of alveolar ridge and functional adaptation, which is very important and advantageous in comparison to osseointegrated implants that are stationary and do not erupt, resulting in infraoccluion.[7]

Successful transplantation of teeth results in improved esthetics, dentofacial development, arch form, arch integrity, mastication, and speech.

CASE REPORT

A 27-year-old female patient was referred to the Department of Conservative Dentistry and Endodontics with a chief complaint of pain in lower left back tooth region since 1-week. Clinical and radiographic examination [Figure 1] revealed grossly carious #37 and horizontally impacted #38. #37 was diagnosed as grossly carious with chronic irreversible pulpitis and symptomatic apical periodontitis with recurrent food lodgment, and #38 was horizontally impacted although being sound mature tooth radiographically. Hence, it was decided to extract #37 and #38 simultaneously and to autotransplant #38 into the extraction site of #37. Complete medical history of the patient was taken and was found to be noncontributory. Treatment plan and postoperative consequences were explained to the patient [Figure 4]; an informed written consent was taken following which the patient was scheduled for a subsequent appointment.

Figure 1

Diagnostic radiograph intra-oral periapical

Figure 4

Post obturation radiograph

A total of 1000 mg Amoxicilin (Novamox, Cipla Ltd., India) and 400 mg Ibuprofen (Flexon, Aristo Pharmaceutical Pvt Ltd., India) was given to the patient 1 h before the procedure to prevent infection, possible resorptive process and post-operative pain. The procedure was started by asking the patient to rinse with Betadine gargles (Win-Medicare Pvt Ltd., India) and proper schedule of surgical disinfection was followed. 2% lignocaine hydrochloride (Lignox 2%, Indoco-Remedies Ltd., India) was administered to anesthetize inferior alveolar, lingual and long buccal nerves. It was decided to extract #37 first followed by impacted #38 thus minimizing the extra-oral time and damage to the periodontal ligament of #38. An intra-crevicular incision was made in relation to #37 and #38. #37 was extracted without damaging the buccal and lingual cortical plates. This was followed by atraumatic removal of impacted #38 with minimal luxation so as to preserve maximum possible periodontal ligament on the root surface. #37 was discarded, and #38 was stored in Hank's balanced salt solution till the time of its transplantation. The root of #38 was examined, and socket preparation of #37 was planned accordingly. Socket of #37 was prepared by using a slow speed surgical round bur (SS White, Dental Pvt Ltd., USA) along with normal saline 0.9% w/v (Alkem Laboratories Ltd., India) as a coolant. The match between the recipient site and the donor's tooth was checked by placing #38 into the socket of #37 with light pressure. All obstacles in the socket wall were eliminated. Occlusion interferences were checked and removed extra orally before final transplantation. Then #38 was autotransplanted into the prepared socket of #37 [Figure 2]. 3-0 silk suture (Sutures India Pvt Ltd., India) was used for suturing of the flap for close approximation and stabilization [Figure 3]. Non-rigid intraradicular splinting was done with malleable orthodontic wire (Tru-Arch, Ormco Ltd., USA) for adequate fixation. Postoperative radiograph was taken to check the position of #38. A Periodontal pack (Coe pack, G C India) as a surgical dressing was applied to protect the transplanted #38 against infection and promote wound healing. The patient was instructed to avoid the use of the operated side for few days, to have soft, lukewarm semi-solid diet and to perform daily rinse with 0.2% w/v chlorhexidine gluconate (Rexidin, Indoco-Remedies Ltd., India) twice a day till further instructions. Patient was put on Amoxicilin 500 mg (Novamox, Cipla Ltd., India) thrice a day, Metronidazole 400 mg (Metron, Ulticare-Alkem Laboratories, India) thrice daily and Ibuprofen 400 mg (Flexon, Aristo Pharmaceutical Pvt Ltd., India) thrice daily for 7 days. The surgical dressing was removed 3 days postsurgery and sutures were removed after 7 days, healing was found to be satisfactory.

Figure 2

Autotransplantation of #38 into the socket of #37

Figure 3

Radiograph after one month depicting resorption of the distal root apex

At 1-month follow-up, intra-oral examination showed the adequate stability of #38 in the socket of #37. A radiograph on the same visit revealed root resorption in relation to the distal root of #38, hence root canal treatment was started immediately. The rubber dam was avoided fearing trauma to #38 by the rubber dam clamp. The access cavity was prepared and adequate working length was established. A radiograph was taken to check the working length. Thorough cleaning and debridement of mesial and distal canals was done using hand NiTi files (Denstply Maillefer, Ballaigues, Switzerland) and alternate irrigation with saline 0.9% w/v (Alkem Laboratories Ltd., India) and 5.2% sodium hypochlorite (Surya Fine Chemicals Ltd., India). Bio-mechanical preparation was done using a standard step back technique. Calcium hydroxide dressing (Metapex, Meta Dental Corporation, USA) was given for 2 weeks to initiate periapical healing and to stop root resorption.

Four weeks follow-up radiographs showed no sign of further root resorption and proper periapical healing. Clinically #38 in the socket of #37 was found to be stable. This was followed by obturation of #38 with Gutta-percha cone (Dentsply Maillefer, Ballaigues, Switzerland) and sealer sealapex (Kerr Corporation, CA, USA) by using cold lateral condensation technique. Master cone and postobturation radiographs were taken [Figure 4]. The patient was advised warm saline rinses 3-4 times daily for 1-month.

Patient follow-up was done after 6 months, 9 months, 12 months and 18 months [Figures 5 and 6] period and healing was evaluated clinically and radiographically. At each visit oral hygiene, stability of the transplant, sulcular depth, gingival recession, occlusion and root resorption were checked and all parameters were found to be satisfactory indicating complete healing in #37 and #38 region.

Figure 5

Radiographic view-18 months follow up

Figure 6

Intra oral view depicting complete healing

DISCUSSION

The earliest known cases of tooth transplantation can be found in Incas civilization and in ancient Egypt where slaves were forced to give their teeth to their pharaohs.[8] The dental surgical intervention of this type was first documented by Abulcassis in 1050; however, the first recorded surgery with details about tooth bud transplantation was performed by the French dentist Ambroise Pare in 1564. A transplantation technique for molars was described in 1956, and until today the general guidelines of this surgical technique are practically the same.[9] Recent development like cone beam computed tomography, two stage transplantation and three-dimensional prototyping have enabled the fabrication of accurate surgical templates which can be used to prepare the recipient site immediately prior to transplantation resulting in decreased extra oral time and improved prognosis.[10]

High success rates of autotransplantation have been reported over the past decade varying from 74% to 100%.[6] Success rate of autotransplantation can be increased by following some simple biological principles. The critical factor for success is favorable periodontal ligament healing, that depends on the number of viable cells preserved on the root surface.[11]

Periodontal cells can also be damaged biochemically due to various stressful extra oral conditions such as variable pH, osmotic pressure, dehydration, etc. The extraoral time should be from 3 to 16 min and during that time donor tooth should be kept moist. Hank's balanced salt solution and coconut water are the best storage media for such tooth.[4] The survival ability of periodontal ligament is significantly reduced after 18 min as prolonged extra oral time increases the possibility of inflammatory root resorption.[12]

Reattachment between the connective tissues of the root surface and the recipient socket walls occurs within 2 weeks.[6] Complete healing occurs within 8 weeks that appears radiographically as a continuous space around the root and presence of lamina dura.[7]

Healing of the root surface of the tooth to be re-implanted depends on the surface area of damaged root to be repopulated. If the area is small, cells with the potential to form new cementum are most likely to cover the damaged root resulting in surface resorption or cemental healing.[13] However if the area is large, cells programmed to form bone get attached to some areas of the root resulting in root resorption and the apposition stage, bone and not dentin fills the previously resorbed area resulting in replacement of root by bone termed as ankylosis (replacement resorption or osseous replacement).[14]

If the pulp space becomes infected, healing is prolonged due to constant stimulus for inflammation by bacteria in the canals. This process has been termed as “inflammatory root resorption.”[15]

In comparison to the use of implants, bone induction around a transplanted tooth is a significant additional advantage. The differentiated osteoblasts may generate bone around the transplant that is observed as a rapid bone regeneration and appearance of lamina dura.[6] Pulp healing response or pulp regeneration can be expected if transplantation of immature teeth is done under optimal conditions, and the diameter of the apical foramen is more than 1 mm radiographically. Through the wide apical foramen, blood capillaries can invade the pulp resulting in differentiation of invading replacement cells into a functional pulp.[5] If a donor's tooth is immature and Hertwig's epithelial sheath is preserved around the apices, continued root development can also be expected. The root development of the donor's tooth should be from 1/3rd to 3/4th of its final documented length.[16]

The tooth should be adequately stabilized for 2 weeks to 2 months depending upon the mobility of transplant. Suture splinting is preferred but if the transplant is not stable with this then splinting is done with wire or adhesive resins splints.[4] Rigid splinting or excessive tying will adversely affect the healing outcome of the transplanted tooth.[8] Taking the above principles into consideration appreciable results in autotransplantation can be achieved.

CONCLUSION

From this case, it is concluded that autogenous transplantation should always be considered as a treatment modality when well indicated. However, patient selection, presence of the suitable donor and appropriate recipient site contributes to its success. All these requires proper planning, good knowledge of exodontia, competence in surgical technique and patient compliance. In this modern era of implants and fixed partial denture, autotransplantation becomes a cost effective method to replace a tooth when the posterior abutment is not available for support. If undertaken properly autotransplantation results in better functional adaptation, biocompatibility in the oral cavity and preservation of the alveolar ridge, hence should be considered as a prime option.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.