) 1991 European Orthodontic Society
European Journal of Orthodontics 13 (1991) 486-492
Autotransplantation of teeth in cases with agenesis or traumatic loss of maxillary incisors L. Kristerson and L. Lagerstrom Department of Oral Surgery, Faculty of Odontology, University of Lund, and Department of Orthodontics, Halmstad, Sweden
The purpose of this study was to investigate the prognosis of 50 consecutively autotransplanted teeth to the maxillary incisor region. Thirty-five were transplanted in cases of traumatic injuries, eleven in cases of agenesis and four in cases with impaction of maxillary canines. The average follow-up time was 7 years and 6 months (range 4-17 years). The transplants were examined clinically in respect of tooth vitality and radiographically in respect of root canal obliteration, periradicular changes, root formation, and root length. The results show a success rate of 82 per cent. It is concluded that the procedure of tooth transplantation has the advantage of maintaining or restoring alveolar bone volume and gives the opportunity to replace a missing tooth without involvement of neighbouring teeth as prosthetic abutments. SUMMARY
Materials
Accidental loss or agenesis of maxillary incisors causes severe treatment problems especially in young individuals. Autotransplantation of teeth to replace lost or missing incisors may be considered if donor teeth are available. Slagsvold and Bjercke (1978) described autotransplantation of premolar tooth germs to the maxillary incisor region after accidental loss of teeth in that region. The success rate was reported to be excellent if the donor teeth were transplanted before completion of root formation. Kristerson and Kvint (1981), Andreasen et al. (1990), and Bowden and Patel (1990) also used premolars as donor teeth to replace lost and missing maxillary incisorswith very good results. Kristerson (1970) reported on the method of using upper third molars to substitute missing maxillary incisors as an alternative to prosthetic solutions. In clinical studies Kristerson (1985) and Andreasen et al. (1990) showed the importance of transplanting premolars at a certain root formation stage to obtain an optimal prognosis of the transplants. The purpose of this study was to investigate the prognosis of consecutively autotransplanted teeth to the maxillary incisor region.
The material for this study was collected from the sample of 550 consecutively autotransplanted teeth performed at the Department of Oral Surgery, Halmstad, Sweden, during the period 1967-1987. Out of this sample 50 teeth were autotransplanted to the maxillary incisor region. Thirty-five of the teeth were transplanted in cases of traumatic injuries. Eleven teeth were transplanted in cases of aplasia of maxillary incisor teeth and four teeth were transplantations of impacted canines into the region of maxillary laterals. Root formation was recorded and analysed according to Kristerson (1985) and Lagerstrom and Kristerson (1986). Donor teeth of stage 2-4 were chosen if available. The stages of root formation are shown in Fig. 1. The sample is described in Table 1 (number of teeth) and Table 2 (stage of root development). The average observation time was 7 years and 6 months (range 4-17 years). Surgical methods
Prior to surgery, patients with missing incisors were evaluated with regard to available space in the recipient region and size of the donor tooth. All operations were performed under local anaesthesia. The procedure began with prepara-
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
Introduction
487
AUTOTRANSPLANTED TEETH
2
S
4
5
6
7
Figure 1 Seven different stages of root formation according to Moorrees et al. (1963), modified by Kristerson (1985). Table 1
Distribution of teeth in the sample.
Source -
Transplants to maxillary incisor region
Premolars Molars Cuspids Incisors
23 18 4 5
Table 2 Distribution of stages of root development in the sample. Stage of root development
Premolars Molars Canines Incisors
Total number of teeth
1
2
3
4
5
6
7
1 5
8 5 1
7 4 1 --2
2
3
1
2 23 3 18 2 4 2 - - - -5
-1
tion of a socket in the recipient area. When transplanting tooth germs, a flap was raised and a crypt prepared with round burs at low speed (less than 2000 rev/min) under aflowof physiologic saline. After radiographic examination the alveolar process was prepared and adjusted to receive the donor tooth. When a tooth with a fully developed root was transplanted an incision was made on the top of the alveolar crest and flaps were raised before the new socket was prepared. The transplants were carefully removed trying to avoid damage to the period-
ontal ligament. The donor tooth was immediately transferred to its new site or kept in physiologic saline at room temperature if further adjustment of the prepared socket was necessary. The follicle was, if possible, kept intact when tooth germs were transplanted. Whenever possible the tooth germs were transplanted to their normal level in the alveolar process according to their stage of root development. The transplanted tooth germs were placed under the mucous membrane and retained with interrupted sutures for up to 1 week. Teeth with full root length were placed at or immediately below the occlusal level and splinted with orthodontic appliances or ligatures for a period of 1-3 weeks (Figs 2 and 3). Immediately after surgery most
Figure 2 Illustration of passive fixation of the transplant with steel ligatures and orthodontic appliance.
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
1
488
L. KRISTERSON AND L. LAGERSTROM
patients began a regimen of 2.0 g phenoxymethyl-penicillin daily for 7 days. Rinsing with Hibitane Dental R. (chlorhexidine) mouthwash daily was recommended. The sutures were removed 1 week after surgery and a radiographic examination was performed. The surgical method is illustrated in Fig. 4 A—M. Post-surgical examinations The autotransplanted teeth were examined according to the procedure described by Kristerson (1985). Clinical and radiographic examinations were done with an interval of 3, 6, and 12 months after surgery, and thereafter annually. The clinical examination involved tooth mobility, gingival examination, occlusal contact, percussion, and vitality test. The radiographic evaluation included obliteration of the pulp cavity, periradicular area, stage of root formation, and increase in root length. The vitality response was recorded using the Bofors
Results
The results of the study are shown in Table 3. In the sample of 23 transplanted premolars three were judged as failures according to stated criteria. Two of these transplants were transplanted at root formation stage 4. Accordingly, they were classified as failures. The third failure was transplanted at stage 7 and was endodontically treated. Inflammatory root resorption was seen, and the transplant was considered as a failure and later extracted. Out of 18 molar transplants in the sample, three were classified as failures. One showed atypical root anatomy and as no pulp revascularization occurred the tooth had to be extracted. The other two were
Table 3 Success and failure rates in relation to type of donor teeth and stage of root development. Stage of root development 1
+
-*
Premolars
2
3
+
+
1
8
;5
3
4 -
5
6
7
+
-
+
+
+
-
5
2
2
3
1
1
2
1
(if-23)
Molars (n=18) Canines
1
Incisors (« = 5) + , Success; —, failure.
1
2
4 1
2
2
I
I
1
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
Figure 3 Illustration of passive fixation of the transplant with surgical sutures.
Pulp Tester with values from 1 to 125 fiA. The readings were registered only as positive or negative. Six teeth were endodontically treated and excluded from this test. Root length was measured according to Kristerson (1985). The following criteria were used for the evaluation of autotransplanted teeth. Success: vitality or alternatively endodontic treatment; normal periodontium (periodontal healing); no progressive root resorption; root development, > 70 per cent of normal root length. Failure: progressive root resorption; root development < 70 per cent of normal root length. All teeth in the sample received composite buildups to create a normal crown anatomy (Fig. 4 H-I, Fig. 5 B-C).
AUTOTRANSPLANTED TEETH
489
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
Figure 4 Illustration of surgical method. A 16-year-old male with traumatic loss of upper left central incisor. (A) Presurgical intra-oral view. (B) Flaps are elevated and recipient socket is prepared. (C) Removal of donor tooth. (D) Donor tooth showing incomplete root formation. (E) Donor tooth transferred to recipient socket. (F) Donor tooth retained with passive steel ligature. (G) Intra-oral view 3 weeks after surgery. (H-I) Intra-oral view 3 years after transplantation with composite build-up of the donor tooth. (J) Radiograph 1 week post-surgery. (K) Radiograph 6 years post-surgery.
endodontically treated, but showed progressive root resorption after 3 years. Four canines were transplanted and two were judged as failures due to presence of inflammatory root resorption. Out of five transplanted incisors in the
sample, four were judged as successful according to the criteria given above. One showed progressive root resorption and was extracted. A case of premolar transplantation is illustrated in Fig. 5 A-I.
L. KRISTERSON AND L. LAGERSTROM
Discussion Bone resorption in the alveolar process after traumatic loss of permanent teeth is similar to the situation where deciduous teeth are lost and permanent teeth are missing. Due to the decrease of alveolar bone volume in the maxillary incisor region, problems may occur when prosthetic rehabilitation has to be performed. Fixed prosthetic procedures may require preparations of intact surrounding teeth for bridge abutments and due to the decreased alveolar bone height aesthetically unpleasing long pontics will give unbalanced gingival configurations. Semi-permanent composite retained bridges can be good as temporary restorations, but as frequent breakages of the composite bond create retention problems there is the risk of caries. Restoration by titanium implants can be successful in adult patients, but the use of single tooth implants is not recommended in growing patients as the implants do not follow the growth of the surrounding alveolar process. Traumatic loss of teeth is often followed by resorption of the alveolar process. Therefore, the procedure can give evident aesthetic and periodontal problems in young growing patients when vertical imbalance is created by further
eruption of neighbouring teeth. Maintenance or restoration of alveolar bone volume in such cases by autotransplantation of teeth has given excellent aesthetic results. The stage of root development has been shown to be one of the main factors affecting the prognosis of an autotransplanted tooth (Kristerson, 1985; Andreasen et al, 1990). If autotransplantation of teeth is used in combination with orthodontic treatment, the timing in relation to root formation can be planned to optimize the chances of a good prognosis. However, in cases with traumatic injuries and loss of teeth the timing of the procedure depends upon the time of the trauma rather than the ideal stage of root formation of the donor tooth. Lagerstrom and Kristerson (1986) reported on the influence of orthodontic movement upon the root development of autotransplanted tooth germs and showed that there was very limited influence on the final root length. This means that autotransplanted teeth can be orthodontically moved without affecting further root development. In this study of 50 teeth consecutively autotransplanted to the maxillary incisor region 35 were replacements of teeth lost due to trauma. Thirty-five out of 50 teeth were transplanted in
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
Figure 5 A 9-year-old male with traumatic loss of upper right central incisor. (A) Presurgical intra-oral view. (B-C) Intraoral view 6 years after transplantation. (D) Presurgical radiograph of traumatized upper central incisor. (E) Radiograph 1 week post-surgery. (F) Radiograph 1 year post-surgery. (G) Radiograph 6 years after transplantation.
491
AUTOTRANSPLANTED TEETH
Conclusions
This study shows (1) a success rate of 82 per cent in a sample of 50 consecutively autotransplanted teeth to the maxillary incisal region; (2) teeth transplanted at stages 2-4 show a success rate of 87 per cent; (3) the procedure of autotransplantation of teeth to an area where teeth are missing has the "advantage of maintaining or restoring alveolar bone volume; (4) a missing tooth can be replaced without involvement of neighbouring teeth as prosthetic abutments. Address for correspondence
Lennart Lagerstrom Tandregleringskliniken Skansgatan 1 C 302 46 Halmstad Sweden References Andreasen J O 1981a Periodontal healing after replantation and autotransplantation of incisors in monkeys. International Journal of Oral Surgery 10: 54-61 Andreasen J O 19816 Relationship between cell damage in the periodontal ligament after replantation and subsequent development of root resorption. Acta Odontologica Scandinavica 39: 15-25 Andreasen JO 1981c Effect of extra-oral period and storage media upon periodontal and pulpal healing after replantation of mature permanent incisors in monkeys. International Journal of Oral Surgery 1: 43-53 Andreasen J O 198lc/ Relationship between surface and inflammatory resorption and changes in the pulp after replantation of permanentincisors in monkeys. Journal of Endodontics 7: 294-301 Andreasen JO, Kristerson L 1981 The effect of limited drying or removal of periodontal ligament. Periodontal healing after replantation of mature permanent incisors in monkeys. Acta Odontologica Scandinavica 39: 1-13 Andreasen J O, Kristerson L, Andreasen F M 1988 Damage to the Hertwig's epithelial root sheath: effect upon growth after transplantation of teeth in monkeys. Endodontics Dental Traumatology 4: 145-51 Andreasen JO, Paulsen H U, YuZ, SchwarzO 1990 A long-term study of 370 autotransplanted premolars. Part III. Periodontal healing subsequent to transplantation. European Journal of Orthodontics 12: 25-37 Bowden D E J, Patel H A 1990 Autotransplantation of premolar teeth to replace missing maxillary central incisors. British Journal of Orthodontics 17: 21-8
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
stages 1-4 (Table 3). Four of these were classified as failures. Two premolars and one molar showed progressive root resorption, but were still in situ during the control period. The fourth failure had an atypical root formation prior to transplantation and no further root formation occurred. This tooth had to be extracted. All the failures had information in the records concerning surgical difficulties at removal from the donor sites. If surgical procedures damage the Hertwig's epithelial root sheath future growth can be limited or inhibited depending on the severity of the damage (Andreasen et al., 1988). Progressive root resorption and ankylosis after autotransplantation of teeth is strongly correlated to damage to the root surface during the surgical procedure (Andreasen, 198 la Ac; Andreasen and Kristerson, 1981). Inflammatory root resorption is dependant upon a combination of damage to the root surface and infection of the pulp (Andreasen, 198 Id). Therefore, when the possibility for revascularization of the pulp is limited or impossible as in stages 5-7, these teeth need root canal therapy within 3 weeks after surgery. Tooth germs at stages 5-6 should be avoided because of difficulties in performing adequate endodontic treatment. In this sample five premolars were transplanted at stages 5 or 6. All were judged as successes. This seems to be a coincidence as a previous study by Kristerson (1985) indicates that the risk of pulp necrosis is very high for donor teeth at stages 5 and 6, and so transplantation of teeth is not advisable. The study includes nine teeth which were transplanted at complete root formation, stage 7. All these teeth were endodontically treated 3-5 weeks after surgery. Five were classified as failures due to progressive root resorption. This is also in accordance with"Kristerson"(1985) and Andreasen et al. (1990) who show a higher failure rate when teeth are transplanted at stage 7. There is also a higher risk of surgical damage to the root surface on fully developed teeth with root resorption as a result. Even though the sample in this study is small it is evident that if the transplantation is performed at stages 2-4 of root formation the chances for a good prognosis are greater. This study also shows that the method of transplantation of teeth will create good periodontal healing with preservation of alveolar bone volume in connection with the transplants (41 out of 50 teeth).
492
L. KRISTERSON AND L. LAGERSTROM
Kristerson L 1970 Unusual case of tooth transplantation; report of case. International Journal of Oral Surgery 22: 841-4
Lagerstrom L, Kristerson L 1986 Influence of orthodontic treatment on root development of autotransplanted premolars. American Journal of Orthodontics 89: 146-50
Kristerson L 1985 Autotransplantation of human premolars. A clinical and radiographic study of 100 teeth. International Journal of Oral Surgery 14: 200-13
Moorrees C F A , Fanning F A , Hunt E E 1963 Age variation of formation stages for ten permanent teeth. Journal of Dental Research 42: 1490-502
Kristerson L, tander—10 598-606
Slagsvold O, Bjercke B 1978 Applicability of autotransplantation in cases of missing upper anterior teeth. American Journal of Orthodontics 74: 410-21
Kvint S 1981 Autotransplantation ars erfarenhet. Tandlakartidningen
av II:
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
European Journal of Orthodontics 13 (1991) 486-492
Autotransplantation of teeth in cases with agenesis or traumatic loss of maxillary incisors L. Kristerson and L. Lagerstrom Department of Oral Surgery, Faculty of Odontology, University of Lund, and Department of Orthodontics, Halmstad, Sweden
The purpose of this study was to investigate the prognosis of 50 consecutively autotransplanted teeth to the maxillary incisor region. Thirty-five were transplanted in cases of traumatic injuries, eleven in cases of agenesis and four in cases with impaction of maxillary canines. The average follow-up time was 7 years and 6 months (range 4-17 years). The transplants were examined clinically in respect of tooth vitality and radiographically in respect of root canal obliteration, periradicular changes, root formation, and root length. The results show a success rate of 82 per cent. It is concluded that the procedure of tooth transplantation has the advantage of maintaining or restoring alveolar bone volume and gives the opportunity to replace a missing tooth without involvement of neighbouring teeth as prosthetic abutments. SUMMARY
Materials
Accidental loss or agenesis of maxillary incisors causes severe treatment problems especially in young individuals. Autotransplantation of teeth to replace lost or missing incisors may be considered if donor teeth are available. Slagsvold and Bjercke (1978) described autotransplantation of premolar tooth germs to the maxillary incisor region after accidental loss of teeth in that region. The success rate was reported to be excellent if the donor teeth were transplanted before completion of root formation. Kristerson and Kvint (1981), Andreasen et al. (1990), and Bowden and Patel (1990) also used premolars as donor teeth to replace lost and missing maxillary incisorswith very good results. Kristerson (1970) reported on the method of using upper third molars to substitute missing maxillary incisors as an alternative to prosthetic solutions. In clinical studies Kristerson (1985) and Andreasen et al. (1990) showed the importance of transplanting premolars at a certain root formation stage to obtain an optimal prognosis of the transplants. The purpose of this study was to investigate the prognosis of consecutively autotransplanted teeth to the maxillary incisor region.
The material for this study was collected from the sample of 550 consecutively autotransplanted teeth performed at the Department of Oral Surgery, Halmstad, Sweden, during the period 1967-1987. Out of this sample 50 teeth were autotransplanted to the maxillary incisor region. Thirty-five of the teeth were transplanted in cases of traumatic injuries. Eleven teeth were transplanted in cases of aplasia of maxillary incisor teeth and four teeth were transplantations of impacted canines into the region of maxillary laterals. Root formation was recorded and analysed according to Kristerson (1985) and Lagerstrom and Kristerson (1986). Donor teeth of stage 2-4 were chosen if available. The stages of root formation are shown in Fig. 1. The sample is described in Table 1 (number of teeth) and Table 2 (stage of root development). The average observation time was 7 years and 6 months (range 4-17 years). Surgical methods
Prior to surgery, patients with missing incisors were evaluated with regard to available space in the recipient region and size of the donor tooth. All operations were performed under local anaesthesia. The procedure began with prepara-
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
Introduction
487
AUTOTRANSPLANTED TEETH
2
S
4
5
6
7
Figure 1 Seven different stages of root formation according to Moorrees et al. (1963), modified by Kristerson (1985). Table 1
Distribution of teeth in the sample.
Source -
Transplants to maxillary incisor region
Premolars Molars Cuspids Incisors
23 18 4 5
Table 2 Distribution of stages of root development in the sample. Stage of root development
Premolars Molars Canines Incisors
Total number of teeth
1
2
3
4
5
6
7
1 5
8 5 1
7 4 1 --2
2
3
1
2 23 3 18 2 4 2 - - - -5
-1
tion of a socket in the recipient area. When transplanting tooth germs, a flap was raised and a crypt prepared with round burs at low speed (less than 2000 rev/min) under aflowof physiologic saline. After radiographic examination the alveolar process was prepared and adjusted to receive the donor tooth. When a tooth with a fully developed root was transplanted an incision was made on the top of the alveolar crest and flaps were raised before the new socket was prepared. The transplants were carefully removed trying to avoid damage to the period-
ontal ligament. The donor tooth was immediately transferred to its new site or kept in physiologic saline at room temperature if further adjustment of the prepared socket was necessary. The follicle was, if possible, kept intact when tooth germs were transplanted. Whenever possible the tooth germs were transplanted to their normal level in the alveolar process according to their stage of root development. The transplanted tooth germs were placed under the mucous membrane and retained with interrupted sutures for up to 1 week. Teeth with full root length were placed at or immediately below the occlusal level and splinted with orthodontic appliances or ligatures for a period of 1-3 weeks (Figs 2 and 3). Immediately after surgery most
Figure 2 Illustration of passive fixation of the transplant with steel ligatures and orthodontic appliance.
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
1
488
L. KRISTERSON AND L. LAGERSTROM
patients began a regimen of 2.0 g phenoxymethyl-penicillin daily for 7 days. Rinsing with Hibitane Dental R. (chlorhexidine) mouthwash daily was recommended. The sutures were removed 1 week after surgery and a radiographic examination was performed. The surgical method is illustrated in Fig. 4 A—M. Post-surgical examinations The autotransplanted teeth were examined according to the procedure described by Kristerson (1985). Clinical and radiographic examinations were done with an interval of 3, 6, and 12 months after surgery, and thereafter annually. The clinical examination involved tooth mobility, gingival examination, occlusal contact, percussion, and vitality test. The radiographic evaluation included obliteration of the pulp cavity, periradicular area, stage of root formation, and increase in root length. The vitality response was recorded using the Bofors
Results
The results of the study are shown in Table 3. In the sample of 23 transplanted premolars three were judged as failures according to stated criteria. Two of these transplants were transplanted at root formation stage 4. Accordingly, they were classified as failures. The third failure was transplanted at stage 7 and was endodontically treated. Inflammatory root resorption was seen, and the transplant was considered as a failure and later extracted. Out of 18 molar transplants in the sample, three were classified as failures. One showed atypical root anatomy and as no pulp revascularization occurred the tooth had to be extracted. The other two were
Table 3 Success and failure rates in relation to type of donor teeth and stage of root development. Stage of root development 1
+
-*
Premolars
2
3
+
+
1
8
;5
3
4 -
5
6
7
+
-
+
+
+
-
5
2
2
3
1
1
2
1
(if-23)
Molars (n=18) Canines
1
Incisors (« = 5) + , Success; —, failure.
1
2
4 1
2
2
I
I
1
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
Figure 3 Illustration of passive fixation of the transplant with surgical sutures.
Pulp Tester with values from 1 to 125 fiA. The readings were registered only as positive or negative. Six teeth were endodontically treated and excluded from this test. Root length was measured according to Kristerson (1985). The following criteria were used for the evaluation of autotransplanted teeth. Success: vitality or alternatively endodontic treatment; normal periodontium (periodontal healing); no progressive root resorption; root development, > 70 per cent of normal root length. Failure: progressive root resorption; root development < 70 per cent of normal root length. All teeth in the sample received composite buildups to create a normal crown anatomy (Fig. 4 H-I, Fig. 5 B-C).
AUTOTRANSPLANTED TEETH
489
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
Figure 4 Illustration of surgical method. A 16-year-old male with traumatic loss of upper left central incisor. (A) Presurgical intra-oral view. (B) Flaps are elevated and recipient socket is prepared. (C) Removal of donor tooth. (D) Donor tooth showing incomplete root formation. (E) Donor tooth transferred to recipient socket. (F) Donor tooth retained with passive steel ligature. (G) Intra-oral view 3 weeks after surgery. (H-I) Intra-oral view 3 years after transplantation with composite build-up of the donor tooth. (J) Radiograph 1 week post-surgery. (K) Radiograph 6 years post-surgery.
endodontically treated, but showed progressive root resorption after 3 years. Four canines were transplanted and two were judged as failures due to presence of inflammatory root resorption. Out of five transplanted incisors in the
sample, four were judged as successful according to the criteria given above. One showed progressive root resorption and was extracted. A case of premolar transplantation is illustrated in Fig. 5 A-I.
L. KRISTERSON AND L. LAGERSTROM
Discussion Bone resorption in the alveolar process after traumatic loss of permanent teeth is similar to the situation where deciduous teeth are lost and permanent teeth are missing. Due to the decrease of alveolar bone volume in the maxillary incisor region, problems may occur when prosthetic rehabilitation has to be performed. Fixed prosthetic procedures may require preparations of intact surrounding teeth for bridge abutments and due to the decreased alveolar bone height aesthetically unpleasing long pontics will give unbalanced gingival configurations. Semi-permanent composite retained bridges can be good as temporary restorations, but as frequent breakages of the composite bond create retention problems there is the risk of caries. Restoration by titanium implants can be successful in adult patients, but the use of single tooth implants is not recommended in growing patients as the implants do not follow the growth of the surrounding alveolar process. Traumatic loss of teeth is often followed by resorption of the alveolar process. Therefore, the procedure can give evident aesthetic and periodontal problems in young growing patients when vertical imbalance is created by further
eruption of neighbouring teeth. Maintenance or restoration of alveolar bone volume in such cases by autotransplantation of teeth has given excellent aesthetic results. The stage of root development has been shown to be one of the main factors affecting the prognosis of an autotransplanted tooth (Kristerson, 1985; Andreasen et al, 1990). If autotransplantation of teeth is used in combination with orthodontic treatment, the timing in relation to root formation can be planned to optimize the chances of a good prognosis. However, in cases with traumatic injuries and loss of teeth the timing of the procedure depends upon the time of the trauma rather than the ideal stage of root formation of the donor tooth. Lagerstrom and Kristerson (1986) reported on the influence of orthodontic movement upon the root development of autotransplanted tooth germs and showed that there was very limited influence on the final root length. This means that autotransplanted teeth can be orthodontically moved without affecting further root development. In this study of 50 teeth consecutively autotransplanted to the maxillary incisor region 35 were replacements of teeth lost due to trauma. Thirty-five out of 50 teeth were transplanted in
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
Figure 5 A 9-year-old male with traumatic loss of upper right central incisor. (A) Presurgical intra-oral view. (B-C) Intraoral view 6 years after transplantation. (D) Presurgical radiograph of traumatized upper central incisor. (E) Radiograph 1 week post-surgery. (F) Radiograph 1 year post-surgery. (G) Radiograph 6 years after transplantation.
491
AUTOTRANSPLANTED TEETH
Conclusions
This study shows (1) a success rate of 82 per cent in a sample of 50 consecutively autotransplanted teeth to the maxillary incisal region; (2) teeth transplanted at stages 2-4 show a success rate of 87 per cent; (3) the procedure of autotransplantation of teeth to an area where teeth are missing has the "advantage of maintaining or restoring alveolar bone volume; (4) a missing tooth can be replaced without involvement of neighbouring teeth as prosthetic abutments. Address for correspondence
Lennart Lagerstrom Tandregleringskliniken Skansgatan 1 C 302 46 Halmstad Sweden References Andreasen J O 1981a Periodontal healing after replantation and autotransplantation of incisors in monkeys. International Journal of Oral Surgery 10: 54-61 Andreasen J O 19816 Relationship between cell damage in the periodontal ligament after replantation and subsequent development of root resorption. Acta Odontologica Scandinavica 39: 15-25 Andreasen JO 1981c Effect of extra-oral period and storage media upon periodontal and pulpal healing after replantation of mature permanent incisors in monkeys. International Journal of Oral Surgery 1: 43-53 Andreasen J O 198lc/ Relationship between surface and inflammatory resorption and changes in the pulp after replantation of permanentincisors in monkeys. Journal of Endodontics 7: 294-301 Andreasen JO, Kristerson L 1981 The effect of limited drying or removal of periodontal ligament. Periodontal healing after replantation of mature permanent incisors in monkeys. Acta Odontologica Scandinavica 39: 1-13 Andreasen J O, Kristerson L, Andreasen F M 1988 Damage to the Hertwig's epithelial root sheath: effect upon growth after transplantation of teeth in monkeys. Endodontics Dental Traumatology 4: 145-51 Andreasen JO, Paulsen H U, YuZ, SchwarzO 1990 A long-term study of 370 autotransplanted premolars. Part III. Periodontal healing subsequent to transplantation. European Journal of Orthodontics 12: 25-37 Bowden D E J, Patel H A 1990 Autotransplantation of premolar teeth to replace missing maxillary central incisors. British Journal of Orthodontics 17: 21-8
Downloaded from http://ejo.oxfordjournals.org/ at Ryerson University on November 18, 2012
stages 1-4 (Table 3). Four of these were classified as failures. Two premolars and one molar showed progressive root resorption, but were still in situ during the control period. The fourth failure had an atypical root formation prior to transplantation and no further root formation occurred. This tooth had to be extracted. All the failures had information in the records concerning surgical difficulties at removal from the donor sites. If surgical procedures damage the Hertwig's epithelial root sheath future growth can be limited or inhibited depending on the severity of the damage (Andreasen et al., 1988). Progressive root resorption and ankylosis after autotransplantation of teeth is strongly correlated to damage to the root surface during the surgical procedure (Andreasen, 198 la Ac; Andreasen and Kristerson, 1981). Inflammatory root resorption is dependant upon a combination of damage to the root surface and infection of the pulp (Andreasen, 198 Id). Therefore, when the possibility for revascularization of the pulp is limited or impossible as in stages 5-7, these teeth need root canal therapy within 3 weeks after surgery. Tooth germs at stages 5-6 should be avoided because of difficulties in performing adequate endodontic treatment. In this sample five premolars were transplanted at stages 5 or 6. All were judged as successes. This seems to be a coincidence as a previous study by Kristerson (1985) indicates that the risk of pulp necrosis is very high for donor teeth at stages 5 and 6, and so transplantation of teeth is not advisable. The study includes nine teeth which were transplanted at complete root formation, stage 7. All these teeth were endodontically treated 3-5 weeks after surgery. Five were classified as failures due to progressive root resorption. This is also in accordance with"Kristerson"(1985) and Andreasen et al. (1990) who show a higher failure rate when teeth are transplanted at stage 7. There is also a higher risk of surgical damage to the root surface on fully developed teeth with root resorption as a result. Even though the sample in this study is small it is evident that if the transplantation is performed at stages 2-4 of root formation the chances for a good prognosis are greater. This study also shows that the method of transplantation of teeth will create good periodontal healing with preservation of alveolar bone volume in connection with the transplants (41 out of 50 teeth).
492
L. KRISTERSON AND L. LAGERSTROM
Kristerson L 1970 Unusual case of tooth transplantation; report of case. International Journal of Oral Surgery 22: 841-4
Lagerstrom L, Kristerson L 1986 Influence of orthodontic treatment on root development of autotransplanted premolars. American Journal of Orthodontics 89: 146-50
Kristerson L 1985 Autotransplantation of human premolars. A clinical and radiographic study of 100 teeth. International Journal of Oral Surgery 14: 200-13
Moorrees C F A , Fanning F A , Hunt E E 1963 Age variation of formation stages for ten permanent teeth. Journal of Dental Research 42: 1490-502
Kristerson L, tander—10 598-606
Slagsvold O, Bjercke B 1978 Applicability of autotransplantation in cases of missing upper anterior teeth. American Journal of Orthodontics 74: 410-21
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