THE INDICATIONS FOR THE TRANSPLANTATION OF MAXILLARY CANINES IN THE LIGHT OF 100 CASES. J. I. Moss, PhD.(Lond.), B.D.S., F.D.S., R.C.S.(Eng.

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1 British Journal of Oral surgery (1975), 12, THE INDICATIONS FOR THE TRANSPLANTATION OF MAXILLARY CANINES IN THE LIGHT OF 100 CASES J. I. Moss, PhD.(Lond.), B.D.S., F.D.S., R.C.S.(Eng.) University College Hospital, Dental Hospital, London Summary. One hundred cases of autogenous transplantation of maxillary canines are reviewed and the results assessed. They were divided into Group A, 50 cases 3 to IO years out of retention, and Group B, 50 consecutive cases I to 3 years out of retention. If the criteria for success depended on a normal response to vitality test, 62 per cent of Group A and 24 per cent of Group B were successful. If a prognosis rating was used, 68 per cent of Group A and 72 per cent of Group B had a good prognosis. THE transplantation of teeth is a subject which has interested people for many years. Many instances of the transplantation of teeth have been reported in the literature. Ambroise Pare reported an instance where a certain princess had an extensively carious tooth removed and replaced by one from a lady-m-waiting. Eventually it became so firm that she masticated with it as well as her others, Guerini (rgog). However, it was John Hunter (1771), the great anatomist, who popularised the procedure and laid down the principles for the transplantation of teeth: (i) Only use healthy people s teeth. (ii) Never attempt it until you have sufhcient donors. (iii) Only use single-rooted teeth. (iv) The root of the transplanted tooth should be shorter than the extracted tooth. (v) The transfer should be with the least possible delay. (vi) The tooth must be immobilised with silk or wire. (vii) Frequent recalls to check the tooth. The many failures of this procedure resulted in its gradual cessation, but at the beginning of this century interest was revived in the practice of autogenous transplantation of teeth. Widman (rgis>, a Swedish oral surgeon, autotransplanted unerupted maxillary canines into their correct positions with good results. Since this time a considerable number of papers have been published describing the results of the autogenous transplantation of maxillary canines with and without root-filling (Fordyce, 1965; Heslop, 1967; Moss, 1968, 1970; Hovinga, 1969; Thormer, 1970). The reason for this interest in canines is threefold. Firstly, the upper canine is the most frequently misplaced tooth in the anterior part of the mouth and, secondly, the alignment of this tooth can be difhcult and protracted. Bass (1967) estimated that the average duration of treatment for 150 patients with misplaced maxillary canines was I year. Thirdly, patients are often unaware that the canine is misplaced until they are in their late teens and early twenties, and at this stage orthodontic treatment is often not acceptable on aesthetic and social grounds. In order to be able to advise the patients who seek a short course of immediate Received Accepted

2 INDICATIONS FOR THE TRANSPLANTATION OF MAXILLARY CANINES 269 orthodontic treatment for an unerupted canine it is essential to be able to look back and assess the results of those teeth which have been transplanted. Unfortunately, as with most long-term surveys, the follow-up of patients is often diflicult due to the patients moving from the area of the surgeon. It is also difficult to get an unbiased sample as patients may return because the result is successful and they are pleased, or it may be that the unsuccessful cases tend to return. Material. In order to eliminate the bias if there was any, 50 cases of autogenous transplantation 3 to IO years out of retention and 50 consecutive cases I to 3 years out of retention were reviewed. These will be referred to as Group A and B respectively. Method. As different operators have different techniques the one which has been used by the author in all these cases will be briefly described. When sufficient space was present in the alveolus for the canine, an impression of the jaw was taken and a cast silver or acrylic cap splint was made on the model over a replica of the canine, slightly enlarged bucco-palatally, in its correct position in the alveolus and the four adjacent teeth, two on each side. The cap over the tooth to be transplanted was cut away occlusally to allow the operator to see the position of the canine after the splint had been cemented. Under endotracheal anaesthesia an injection of local anaesthetic with a vasoconstrictor was given in the area of the canine as this not only acts as a local haemostatic agent but also constricts the vessels of the pulp of the tooth to be transplanted. A palatal flap was raised by making an incision around the necks of the adjacent teeth, cutting the gingival margins for the canine to be transplanted at the same time. A large buccal flap extending from the molars to the central incisor was used in cases of transposition of the canine, where it was erupted and was found in the second premolar region. Bone was carefully removed with chisels, and the bone which was removed was placed in warm normal saline at body temperature. The tooth was exposed until it could be elevated carefully and inserted into its correct position. A new socket for the tooth was then cut in the alveolus. If the socket could not be cut because of the position of the canine, the canine was removed carefully from its socket and placed beneath the palatal flap, making sure that the root did not touch the epithelial surfaces of the flaps, mouth or adjacent tooth crowns. Once the tooth could be inserted into its correct position, bone chips were replaced round the root of the tooth and the wound closed with interrupted sutures making sure that they were placed well down in the palate to facilitate their removal when the splint was in place. The splint was then cemented with Germicidal Kryptex cement and the patient placed on an antibiotic cover for 5 days. The sutures were removed in 7 days and the splint after 6 weeks. When the splint was removed the bite was carefully checked as it was necessary to prevent occlusal trauma to the tooth, especially in lateral excursions of the jaw. If any interference was found, the teeth were ground slightly so that the canine was clear of the bite during the excursions of the jaw. ASSESSMENT OF THE RESULTS The criteria used in the assessment of the results of this series of transplanted canines were based on the criteria of Fong (Igjj), Clark, Tam and Mitchell (rg54),

3 270 BRITISH JOURNAL OF ORAL SURGERY and Nordenram (1963). A successful result was described as a tooth with gingival tissues firmly attached to the tooth, with the tissues bacteriologically and functionally the same as the tooth on the opposite side. It should be in a normal position with normal vitality, and radiological examination should reveal a normal periodontal membrane and lamina dura with no evidence of periapical lesions. The teeth were also given a prognosis rating. This was a rating based on clinical experience as to whether the tooth had a good prognosis and would remain with the patient indefinitely, or whether the tooth showed signs that it was going to be lost. Ten factors were taken into consideration when assessing the results. (I) The Position of the Tooth in the Alveolus. This was assessed as good, fair or poor. In Group A, 46 were assessed as good, three fair and one poor, and in Group B, 41 were assessed as good, eight fair and one poor. (2) The Contacts with the Adjacent Teeth. In some cases where the space was more than adequate, or where it had been reopened too much, contacts following the operation would not have been present but would have been established with the normal mesial migration of the teeth. In Group A, 32 had contacts, 12 had contact on one side only and six had no contacts. In Group B, 28 had good contacts, I 5 had contact on one side only and six had no contacts. It seemed, therefore, that if contact was re-established it occurred within 3 years. (3) The Mobility of the Teeth. The third factor assessed was the mobility of the teeth, whether the teeth showed any abnormal mobility and were loose. In Group A, 46 had no abnormal mobility and four were mobile. In Group B, 43 were normal and seven showed abnormal mobility. (4) The CoZour of the Tooth. The colour of the tooth was assessed by comparing it with the same tooth on the other side and the adjacent teeth and graded as normal, slightly dark or dark. In Group A, 34 were normal, 13 slightly dark and three dark, whereas in Group B, 40 were normal, nine slightly dark and one dark. This indicated that transplanted teeth tend to become darker as time elapses. (5) The Vitality of the Teeth. The vitality of the teeth was tested both thermally and with an electric pulp tester, and the results were compared with the adjacent teeth and the corresponding tooth on the opposite side. It was difficult to know whether it was the tooth that responded or whether the response came from the periodontal membrane. In Group A, 28 had a normal vitality, 12 had a decreased vitality and IO were non-vital. In Group B, 13 had a normal vitality, 22 had a decreased vitality and 15 were non-vital. If the vitality of a transplanted tooth was followed over a period of 2 years or more it seemed to regain its vitality, Moss (1971), and this may explain the difference in vitality between the two groups. Rock et al. (1974) showed that 55 per cent of traumatised anterior teeth which were non-vital at the time when first seen were vital after 2 years. (6) Changes in the Pulp Chamber. The sixth factor assessed was whether the pulp chamber showed any reduction in size. These changes were assessed from intra-oral radiographs. In Group A, 29 showed no changes and 21 showed a decrease in the size of the pulp chamber. In Group B, 35 showed no change, 14 showed a decrease in size, and one showed an enlargement of the pulp chamber. This indicated that the laying down of osteodentine in the pulp chamber was a change which occurred after a period of time. (7) Resorption of the Root. R esorption, if it occurred, was of two types. One was a limited resorption which occurred usually on the distal aspect of the tooth

4 INDICATIONS FOR THE TRANSPLANTATION OF MAXILLARY CANINES 271 near the region where the alveolar bone might have damaged the cementum during the removal of the tooth. This resorption did not progress. The second form of resorption was gross and progressive and nothing seemed to stop it, not even root-filling the tooth. In Group A, 3 I showed no resorption, I I showed a limited resorption and eight progressive resorption. In Group B, 31 showed no resorption, 13 showed a limited resorption and six showed progressive resorption. If a tooth showed signs of resorption it did so within the first 3 years and therefore this gave a good indication of the prognosis for the tooth. (8) The GingivaZ Attachment. This was assessed using a measuring probe, and the depth of the pockets mesially, distally, bucally and palatally were recorded. The tooth was then graded according to the depth of the deepest pocket. In Group A, 43 had a pocket depth of 3 mm or less, and seven were more than 3 mm. In Group B, 42 had a pocket depth of 3 mm or less, and eight were more than 3 mm. (9) The Presence of the Periodontal Membrane and Lamina Dura. These were assessed from the intra-oral X-rays. In Group A, 40 were normal and in IO it was incomplete. In Group B, 30 were normal and 20 had an incomplete periodontal membrane and lamina dura. (IO) The Condition of the Alveolar Bone. This was also assessed from intraoral radiographs. In Group A it was normal in 40 cases, and IO showed areas of rarefaction either periapically or at the alveolar crest. In Group B, 41 were normal and nine showed rarefaction. RESULTS Using the criteria of Fong (1g53), Clark, Tam and Mitchell (1954) and Nordemam (1963) 31 were successful, 62 per cent in Group A, and in Group B 12 were successful, 24 per cent. However, using a prognosis rating based on clinical experience, each tooth was assessed as to whether it would remain indefinitely in the mouth and had a good prognosis, fair if it would remain for some years, and poor if it would be lost within 4 years. In Group A, 34 had a good prognosis, seven fair, six poor and three were extracted. In Group B, 36 had a good prognosis, five fair, seven poor and two had been extracted. From these results it is evident that both the 50 cases 3 years or more out of retention and the 50 consecutive cases show a similar pattern, and it therefore seems that using this technique these are the results obtainable. DISCUSSION If the criteria of Fong (1g53), Clark, Tam and Mitchell (1954) and Nordenram (1963) for a successful transplantation were used, 3 I cases of Group A and 12 cases of Group B would be classified as successful. The better results in Group A were due to the number of teeth which responded to vitality tests. In a previous paper it was shown that the vitality of transplanted canines improved as the number of years out of retention increased (Moss, 1971). Recently Rock et al. (1974) reported that 55 per cent of traumatised anterior teeth which were non-vital at the time they were first seen responded to vitality tests 2 years later. The traumatised anterior teeth, however, were not removed from their sockets whereas the transplanted teeth were placed into a new socket cut in the bone. Measurement of the intra-oral radiographs showed that the apices of all the canines that were transplanted had

5 272 BRITISH JOURNAL OF ORAL SURGERY FIG. I Case I. A, May B, November C, June D, July The tooth was transplanted when the patient was 15 years old and within a year it responded to vitality. The vitality response of the tooth is still normal and it has a normal gingival margin. moved at least IO mm, and the majority had closed apices. Whether the improvement in the vitality was due to a re-innervation of the tooth or periodontal membrane was diflkult to assess, but the response of the teeth definitely changed, as can be seen from the improved response in the group 3 to IO years out of retention. As the defined criteria for success were dependent on a normal vitality response and this changed, it was decided to give each tooth a prognosis rating in the light

6 INDICATIONS FOR THE TRANSPLANTATION OF MAXILLARY CANINES 273 FIG. 2 Case 2. A, March B, September C, October D, September The 3/3 were transplanted when the patient was 15 years old and within 6 months the laminaura was forming. There was gradual obliteration of the pulp chamber. In September 1973 the teeth responded to vitality tests but were slightly darker in colour. of experience, taking into account the various factors which would result in the ultimate loss of the tooth. Each case was reassessed individually without reference to the group to which it belonged and given a prognosis rating. A good prognosis was given to teeth which would remain indefinitely and a poor prognosis to those teeth which showed signs that they would ultimately be lost. Factors which were considered to be important in the determination of the prognosis of the teeth were the presence of resorption of the root or the alveolar bone, and the depth of periodontal pockets and the presence of a lamina dura. In Group A, 34 had a good prognosis, seven fair, six poor and three were extracted. In Group B, 36 had a good prognosis, five fair, seven poor and two had been extracted. It was interesting to see that the prognosis for a successful result in the two groups was similar. Apart from the vitality of the teeth, there were three other areas where there was a difference between the two groups. The first was the difference in colour, the teeth in Group A being darker than those in Group B. A slight darkening of the colour might be expected with a decrease in the size of the pulp chamber, but it might also be due to breakdown products from the pulp entering the dentinal tubules. The second area was the decrease in the size of the pulp chamber which was found most frequently in Group A. The third area was the presence of the periodontal membrane and lamina dura. In Group A, 40 were normal whereas in Group B only 30 were normal. The periodontal membrane and lamina dura

7 274 BRITISH JOURNAL OF ORAL SURGERY were often complete within g to 12 months in teeth which had a good prognosis whereas those which had a poor prognosis did not show a complete lamina dura even 4 or 5 years later. The resorption which occurred was of two types, a limited resorption and a progressive resorption. The number of cases showing these types of resorption were similar in both groups. This seemed to indicate that those cases which will fail and have a poor prognosis can be assessed within the first 3 years. The attachment of the periodontal membrane was good in the majority of cases, but where pocketing was present it indicated that the tooth had a poor prognosis. The importance of protecting the gingival margin cannot be overemphasised, once debris has become trapped between the flap and the root the chances of a successful result were poor. This was another reason for enlarging the splint bucco-palatally as the splint then protected the gingival region round the tooth. Similarly, if the blood clot became infected the chances of a successful transplant were minimal. The autogenous transplantation of canines can be used in cases where there is adequate space for the canine in the dental arch, if it is of good morphology and the tooth can be removed whole without excessive damage to the root. It can be undertaken at any age but is more applicable to the older age-group where orthodontic treatment needs to be reduced to the minimum for aesthetic and social reasons. Transposition and dilaceration are other instances where the autogenous transplantation of teeth has been used and has been found to be a valuable surgical adjunct to orthodontic treatment. Two cases are illustrated (Figs. I and 2). REFERENCES BASS, T. (1967). Dental Practitioner, IS, 25. CLARK, H. B., TAM, J. C. & MITCHELL, D. F. (1954). Journal of Dental Research, 33,653. FONG, C. C. (1953). Oral Surgery, Oral Medicine and Oral Pathology, 6, 917. FONG, C. C.&AGNEW, R. G. (1958). J ournal of the American Dental Association, 56, 77. FORDYCE, G. L. (1965). Dental Practitioner, IS, 388. GUERINI, V. (1909). History of Dentistry; from the most ancient time until the end of the 18th century, p. Igt. Philadelphia: Lea and Febiger. HESLOP, I. H. (1967). British Journal of Oral Surgery, 5, 135. HOVINGA, J. (1969). Journal of Oral Surgery, 27, 701. HUNTER, J. (1771). Natural History of the Human Teeth, Vol. I, p London: J. Johnson. Moss, J. P. (1968). Journal of Oral Surgery, 26, 775. Moss, J. P. (1970). Journal of Clinical Orthodontics, 4, 77. MOSS, J. P. (1971). Dental Practitioner, 22, 241. NORDENRAM, A. (1963). Acta Odontologica Scandinavica, 21, I (suppl. 33). ROCK, W. P., GORDON, P. H., FRIED, L. A. & GRLJNDY, M. C. (1974). British Dental Journal, 136, 236. THONNER, K. E. (1969). Dental Practitioner, 21, 251. WIDMAN, L. (1916). Svensk. Tandlak. T. 8, 131.