Miller H. Tooth transplantation. J Oral Surg. 1951; 9
Slagsvold O, Bjerke B. Autotransplantation of premolars with partly formed roots. A radiographic study of root growth. Am J Orthod. 1974; 66:355-366
Czochrowska EM, Stenvik A, Bjercke B, Zachrisson BU. Outcome of tooth transplantation: survival and success rates 17–41 years post-treatment. Am J Orthod Dentofacial Orthop. 2002; 121:110-119
Tsukiboshi M. Autotransplantation of Teeth.Tokyo: Quintessence; 2001
Paulsen HU, Andreasen JOl. Eruption of premolars subsequent to autotransplantation. A longitudinal radiographic study. Eur J Orthod. 1998; 20:45-55
Czochowska EM, Stenvik A, Album B, Zachrisson BU. Autotransplantation of premolars to replace maxillary incisors: a comparison with natural incisors. Am J Orthod Dentofacial Orthop. 2000; 118:592-600
Shargill I, Nandra S, Day P, Houghton N. Patient and parent satisfaction following autotransplantation and associated orthodontic treatment delivered by an interdisciplinary team. Eur Arch Paediatr Dent. 2014; 15:27-32
Andreasen JO, Paulsen HU, Yu Z, Bayer T, Schwartz O. A long term study of 370 autotransplanted premolars. Part II. Tooth survival and pulp healing subsequent to transplantation. Eur J Orthod. 1990; 12:14-24
Denys D, Shahbazian M, Jacobs R Importance of root development in autotransplantations: a retrospective study of 137 teeth with a follow-up period varying from 1 week to 14 years. Eur J Orth. 2013; 35:680-688
Diaz JA, Jans GA, Zaror CE. Long-term evaluation and clinical outcomes of children with dental transplants in Temuco City, Chile. Eur J Paediatric Dent. 2014; 15:6-12
Frenken JW, Baart JA, Jovanovic A. Autotransplantation of premolars. A retrospective study. Int J Oral Maxillofac Surg. 1998; 27:181-185
Jonsson T, Sigurdsson TJ. Autotransplantation of premolars to premolar sites. A long-term follow-up study of 40 consecutive patients. Am J Orthod Dentofacial Orthop. 2004; 125:668-675
Josefsson E, Brattstrom V, Tegsjo U, Valerius-Olsson H. Treatment of lower second premolar agenesis by autotransplantation: four-year evaluation of eighty patients. Acta Odont Scand. 1999; 57:111-115
Kristerson L, Lagerstrom L. Autotransplantation of teeth in cases with agenesis or traumatic loss of maxillary incisors. Eur J Orthod. 1991; 13:486-492
Kugelberg R, Tegsjo U, Malmgren O. Autotransplantation of 45 teeth to the upper incisor region in adolescents. Swed Dent J. 1994; 18:165-172
Lundberg T, Isaksson S. A clinical follow-up study of 278 autotransplanted teeth. Br J Oral Maxillofac Surg. 1996; 34:181-185
Marcusson KAM, Lilja-Karlander EK. Autotransplantation of premolars and molars in patients with tooth aplasia. J Dent. 1996; 24:355-358
Mensink G, van Merkesteyn R. Autotransplantation of premolars. Br Dent J. 2010; 208::109-111
Slagsvold O, Bjercke B. Autotransplantation of premolars with partly formed roots. A radiographic study of root growth. Am J Orthod. 1974; 66:355-366
Tanaka T, Deguchi T, Kageyama T, Kanomi R, Inoue M, Foong KW. Autotransplantation of 28 premolar donor teeth in 24 orthodontic patients. Angle Orthod. 2008; 78:12-19
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Management of severe traumatic injuries and complex dental anomalies in children requires a holistic approach with planning for both short- and long-term eventualities. The goal is to provide biological treatment that maximizes the long-term dental health, appearance and function. Tooth autotransplantation is one potential solution for tooth replacement that is able to fulfil these aims. This series of four articles provides an overview of autotransplantation, including a description of the biological basis for the technique and factors affecting success. It will also provide an outline of the indications and the procedures involved for performing autotransplantation, including the interdisciplinary approach to treatment planning and management. This first article discusses the history of tooth transplantation, indications and the factors that can influence outcome.
CPD/Clinical Relevance: Orthodontists should be aware that tooth autotransplantation is a highly versatile technique with good success rates if used in favourable cases. This method should be considered part of the armamentarium for tooth replacement in a growing child.
Article
Tooth transplantation is the controlled extraction and re-implantation of a donor tooth to a recipient site. Reports of tooth transplantation date back to the 16th century1 but, in these cases, teeth were usually taken from one person and transplanted to another, leading to problems with rejection due to poor knowledge of histocompatibility. Autotransplantation, also known as autologous tooth transplantation, was developed to overcome this problem by extracting and replanting a tooth or teeth within the same person. Autotransplantation was first reported in the 1950s in relation to impacted third molars but the outcomes were highly variable.2 Premolar autotransplantation into the premaxilla was initiated in the 1970s and remains the most popular technique.3,4 Subsequent advancements in the understanding of periodontal ligament healing mechanisms have contributed to the adoption of more atraumatic surgical techniques, with favourable outcomes.5
Uses for tooth autotransplantation
Autotransplantation is a versatile technique that can be used in many clinical situations to replace teeth that are either missing or of poor prognosis. Theoretically, any tooth can be transplanted to any recipient site, although this is limited by the size of the donor tooth and resulting scope for camouflage, bone volume and proximity of adjacent structures in the recipient site. The potential uses for autotransplantation are described in Table 1. The most common application for autotransplantation is tooth replacement arising as a result of:
Tooth loss due to dental trauma, for example avulsion without re-implantation (Figure 1a);
Traumatized teeth with poor prognosis due to replacement resorption or root fracture (Figures 1b and c);
Developmental anomalies, such as dens invaginatus or molar-incisor hypomineralization, with post-eruptive enamel breakdown;
Teeth with poor prognosis due to pathology, for example extensive caries or persistent periapical infection. Caution is needed with such cases and the patient would need to be dentally fit before transplantation would be considered;
Hypodontia in isolation or in combination with cleft lip and palate (Figure 1d);
Ectopic or dilacerated teeth that have failed to erupt and cannot be aligned with orthodontic treatment (Figure 1e);
Teeth with poor prognosis due to root resorption caused by ectopic teeth (Figure 1f).
Tooth Requiring Replacement
Common Aetiology for Tooth Replacement
Preferred Donor Tooth
Central incisor
Traumatic tooth lossPoor prognosis following traumaEctopic or dilacerated
PremolarCanine
Lateral incisor
HypodontiaTrauma
Lower incisor
Canine
Ectopic
Premolar
Premolar
HypodontiaDevelopmental anomaly
PremolarCanineThird molar*
First permanent molar
Poor prognosis
PremolarThird molar*
Figure 1. Uses for autotransplantation include the following. (a) Loss of the maxillary right central incisor following avulsion injury. (b) Infraocclusion of the maxillary right central incisor resulting from ankylosis of the tooth following avulsion and replantation. (c) A fracture in the middle third of the root of the maxillary right central incisor following a traumatic injury. (d) An OPT showing hypodontia affecting the maxillary left lateral incisor and canine and the mandibular right second premolar. (e) Ectopic upper right central and lateral incisors. Due to the severity of the ectopia, the central incisor was judged to be unalignable. (f) Severe root resorption on the upper left central incisor caused by a palatally ectopic maxillary canine tooth.
Periodontal healing results in a viable periodontal ligament
Suitable for use in growing child
Donor tooth can be moved orthodontically
Maintenance of alveolar bone
Potential for bone development through early transplantation of immature teeth
Good survival (>86%) and success (>80%) rates reported
High levels of patient satisfaction
Complex treatment requiring high co-operation
Treatment can be time consuming
Temporary compromise to aesthetics prior to donor tooth camouflage
Risk of biological complications including failure of periodontal ligament healing pulp necrosis and reduced gingival health
Tooth autotransplantation is a biological technique with a number of advantages for the supporting tissues in growing children. Careful planning and timing can utilize the physiological mechanisms of eruption and tooth development to optimize alveolar bone volume. Presence of the donor tooth in the recipient site maintains bone and avoids potential complications that arise from loss of bone volume in edentulous sites. Alveolar bone growth can be induced by autotransplantation of immature teeth early, which are placed high to encourage eruption and associated bony infill in deficient areas.6 Immature teeth have been shown to demonstrate continued root development and gingival growth following transplantation (Figures 2a and 2b).
Figure 2.
(a, b) Radiographic evidence of a transplanted premolar tooth in the maxillary left central incisor showing root formation and pulp healing with pulp canal obliteration.
Autotransplantation aims to provide periodontal healing with maintenance of a viable periodontal ligament. This is advantageous over other tooth replacement methods for growing children, as eruption of the donor tooth will occur with normal growth, preventing infraocclusion. Furthermore, the donor teeth are amenable to orthodontic movement following healing. In cases where the periodontal ligament healing fails and the transplanted tooth becomes ankylosed, the transplant can still be considered an interim solution for tooth replacement that maintains bone, avoids an interim prosthesis, and thus increases the long-term options.
Patient-reported outcomes from autotransplantation in terms of dental appearance and satisfaction have been shown to be good. A study comparing transplanted teeth to their natural contralateral tooth reported that the majority of patients found the appearance to be acceptable.7 Oral health following autotransplantation was found to be good and the majority of patients surveyed after autotransplantation expressed satisfaction with the technique.4 In the UK, patients have reported a high level of satisfaction with both the procedure and the management of transitions between the members of the interdisciplinary team.8
Like all techniques, autotransplantation does have potential disadvantages in terms of treatment burden and risks. Biological complications may arise, including pulp necrosis, external root resorption or loss of periodontal attachment.5 The technique requires an invasive surgical procedure followed by extensive restorative and orthodontic treatment. Treatment can take several years to complete and requires the patient and family to attend dental appointments regularly during an often busy and important period in the child's schooling. Consequently, autotransplantation is only suitable for those who are highly motivated, committed and co-operative. Immediately post-transplantation, temporary concerns can arise around dental appearance prior to the restorative camouflage of the donor tooth. While an interim restorative camouflage can improve aesthetics, this should be balanced against the risk of obscuring the underlying tooth morphology that aids orthodontic tooth positioning. Finally, an interdisciplinary team with the relevant skill set is essential for the management of these cases and lack of availability may prohibit this treatment option.
Prerequisites for autotransplantation
Tooth autotransplantation is not suitable in all cases. Case selection depends on the need for orthodontic treatment, with availability of a suitable donor tooth and adequate bone in the recipient site.
Availability of a donor tooth
In most cases, autotransplantation should be carried out as a part of an orthodontic treatment plan where it has been judged that the patient requires extraction(s) for correction of the malocclusion. A careful and thorough orthodontic treatment plan is one key to the success of this technique, as most cases will require pre- and/or post-transplantation orthodontic treatment to achieve the best possible long-term outcome. Furthermore, the tooth for extraction needs to be suitable to act as a donor tooth. Treatment planning, including the orthodontic aspects of autotransplantation, is discussed fully in the second article in this series.
Availability of adequate bone
The volume and quality of alveolar bone in the recipient site is crucial to the success of the technique. Clinicians who wish to include autotransplantation in their clinical practice should have a firm understanding of bone assessment and management for planning treatment. This is discussed further in part three of this series.
Survival and success of transplanted teeth
Survival is universally defined as the continued presence of the transplanted tooth in the mouth. Success, however, is more variably defined and may include periodontal and pulp healing, root development, health of supporting tissues and aesthetic and functional outcomes (Figure 3). Success and survival rates from 16 studies4,7,8,9,10,11,12,13,14,15,16,17,18,19,20-22 are summarized in Table 3. Heterogeneity in the success criteria across studies has contributed to some difficulties when attempting to collate results. A recent systematic review evaluated the outcomes of autotransplantation of immature and mature teeth, with a minimum of 6 years follow-up, and found an 81% survival rate, with 4% ankylosis and 4% resorption rates.23
Figure 3. Tooth transplantation can provide a highly aesthetic outcome. (a, b) A 12-year-old male presented with loss of the maxillary left central incisor following an avulsion injury. The right central incisor had been endodontically treated post-trauma. (c, d) A premolar was transplanted into the maxillary left incisor position, and the patient then underwent comprehensive orthodontic treatment. Post-orthodontic restorative camouflage of the transplanted tooth involved gingival recontouring and a composite veneer. The discoloured right central incisor was managed with internal bleaching.
Periodontal healing following transplantation is a key aim of treatment and is generally used as one of the primary measures of success. The surgical technique should be minimally traumatic to preserve the periodontal ligament of the donor tooth. Periodontal healing is demonstrated by continued eruption of the donor tooth and successful movement following application of orthodontic force.
Pulpal healing
Donor teeth with incomplete root development are expected to achieve revascularization and continued root development after transplantation. Pulp canal revascularization with initial positive vitality testing and subsequent pulp canal obliteration is observed in the majority of transplanted immature teeth23 (Figure 2). Donor teeth with completed root formation at the time of transplantation are not expected to revascularize and elective endodontic intervention involving pulp extirpation and root canal obturation will be required.
Prognostic factors affecting outcomes
A number of studies have attempted to identify which prognostic factors will influence the outcomes of autotransplantation.9,24,25,26-27 Prognostic factors are reported below in relation to their effect on pulp healing, periodontal ligament healing and presence of root resorption.
Stage of donor tooth root development
The stage of root development has been repeatedly demonstrated to be the key determinant for survival, with 75% root formation optimal.9 The stage of root development influences periodontal ligament healing and ankylosis, pulp necrosis and root resorption.24,28 Pulp revascularization occurs more frequently in immature teeth and an apical foramen measuring over one millimetre diameter is related to a lower risk of necrosis. Immature teeth showed a significant decrease in infection-related root resorption and replacement resorption.9 The stage of root development of the donor tooth has been identified as the best predictor for future root resorption.25
Alveolar bone deficiency
Root resorption appears to be increased in teeth re-implanted to narrow alveolus,9 possibly as a result of proximity or even compression of the root into alveolar bone.
Donor tooth
The type of donor tooth has been shown to influence outcomes, with canines and premolars demonstrating more favourable periodontal healing than molars.24 This may be attributed to conical, smooth roots enabling a more atraumatic extraction with reduced trauma to the periodontal ligament.
Socket preparation and surgical technique
Autotransplatation is technique sensitive and the method of socket preparation and transplantation impacts on the outcome. For cases where socket preparation is required, burs with cooling devices decrease the risk of pulp necrosis, possibly as a result of reduced bacterial contamination. Prolonged extra-alveolar time and increased handling of the graft may increase the risk of bacterial contamination and subsequently reduce pulpal healing.9,24
Surgeon skill
As with many techniques, operator skill is important and transplants performed by more experienced surgeons have a significantly better prognosis.26 Autotransplantation involves a highly meticulous procedure, requiring experience and knowledge, and respecting the integrity of the periodontal ligament of the donor tooth during surgery is of paramount importance.
Conclusions
Autotransplantation is a versatile technique with numerous applications in growing children requiring tooth replacement. Survival and success rates have been shown to be high but are dependent on factors relating to the donor tooth, recipient site and surgical technique. Success is measured in relation to healing of the periodontal ligament and pulp, health of surrounding tissues, aesthetic and functional outcomes, including patient and parent satisfaction.
