A long-term study of 370 autotransplanted premolars. Part IV. Root development subsequent to transplantation

Clinical study on prognostic factors for autotransplantation of teeth with complete root formation

Autotransplantation is often performed to replace a missing tooth, but tooth autotransplantation has been reported in fewer teeth with complete root formation than those with incomplete root formation. The aim of this prospective study was to evaluate the factors that affect the prognosis of autotransplantation of teeth with complete root formation. 109 patients with 117 transplants were studied. Of the 117 transplants investigated, 14 (12%) failed during the observation period. The overall 1-year survival rate was 96%; the 5-year survival rate was 84%. The major causes of failure were unsuccessful initial healing and replacement root resorption with periodontal inflammation. Factors significantly associated with unsuccessful transplantation, in single factor analysis, were age 40 years or more, molar tooth as donor, probing pocket depth to 4mm or more, history of root canal treatment, multi-rooted teeth and fixation with sutures. Pocket depth of 4mm or more and history of root canal treatment appeared to increase the risk of unsuccessful transplantation in multivariate analysis. It is suggested that the pocket depth of the donor tooth and history of root canal treatment are related to the healing of paratransplantal tissue and root resorption.

Autotransplantation of premolars

Autotransplantation is a reliable treatment option for the replacement of missing teeth; however, there is a wide variation in reported survival rates. The purpose of this study was to evaluate the success and survival rate of premolar autotransplantation and to underline the importance of autotransplantation in the treatment of missing teeth. We present the treatment and follow-up of 63 premolar autotransplants in 44 patients. After transplantation under local anaesthesia, radiological and clinical follow-up showed a survival rate of 100%, ie all premolars were still functional. We conclude that autotransplantation of premolars is a reliable treatment method especially for agenesis. It is not difficult to perform and is aesthetically superior and more cost-effective than other treatments, especially when orthodontic alignment is necessary.

Vital pulp therapy-current progress of dental pulp regeneration and revascularization

Pulp vitality is extremely important for the tooth viability, since it provides nutrition and acts as biosensor to detect pathogenic stimuli. In the dental clinic, most dental pulp infections are irreversible due to its anatomical position and organization. It is difficult for the body to eliminate the infection, which subsequently persists and worsens. The widely used strategy currently in the clinic is to partly or fully remove the contaminated pulp tissue, and fill and seal the void space with synthetic material. Over time, the pulpless tooth, now lacking proper blood supply and nervous system, becomes more vulnerable to injury. Recently, potential for successful pulp regeneration and revascularization therapies is increasing due to accumulated knowledge of stem cells, especially dental pulp stem cells. This paper will review current progress and feasible strategies for dental pulp regeneration and revascularization.

Formation of the tooth-bone interface

Not only are teeth essential for mastication, but also missing teeth are considered a social handicap due to speech and aesthetic problems, with a resulting high impact on emotional well-being. Several treatment procedures are currently available for tooth replacement with mostly inert prosthetic materials and implants. Natural tooth substitution based on copying the developmental process of tooth formation is particularly challenging and creates a rapidly developing area of molecular dentistry. In any approach, functional interactions among the tooth, the surrounding bone, and the periodontium must be established. Therefore, recent research in craniofacial genetics searches for mechanisms responsible for correct cell and tissue interactions, not only within a specific structure, but also in the context of supporting structures. A tooth crown that is not functionally anchored to roots and bone is useless. This review aims to summarize the developmental and tissue homeostatic aspects of the tooth-bone interface, from the initial patterning toward tooth eruption and lifelong interactions between the tooth and its surrounding alveolar bone.

Pulpal regeneration following allogenic tooth transplantation into mouse maxilla

Autogenic tooth transplantation is now a common procedure in dentistry for replacing a missing tooth. However, there are many difficulties in clinical application of allogenic tooth transplantation because of immunological rejection. This study aims to clarify pulpal regeneration following allogenic tooth transplantation into the mouse maxilla by immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU) and nestin, and by the histochemistry for tartrate-resistant acid phosphatase (TRAP). The upper right first molar (M1) of 2-week-old mice was extracted and allografted in the original socket in both the littermate and non-littermate after the extraction of M1. Tooth transplantation weakened the nestin-positive reactions in the pulp tissue that had shown immunoreactivity for nestin before operation. On postoperative Days 5-7, tertiary dentin formation commenced next to the preexisting dentin where nestin-positive odontoblast-like cells were arranged in all cases of the littermate group until Day 14, except for one case showing immunological rejection in the pulp chamber. In the non-littermate group, bone-like tissue formation occurred in the pulp chamber in addition to tertiary dentin formation until Day 14. The rate of tertiary dentin was 38%, and the rate of the mixed form of dentin and bone-like tissue formation was 23% (the remainder was immunological rejection). Interestingly, the periodontal tissue recovered even in the case of immunological rejection in which the pulp chamber was replaced by sparse connective tissue. These results suggest that the selection of littermate or non-littermate is decisive for the survival of odontoblast-lineage cells and that the immunological rejection does not influence the periodontal regeneration.

Orthodontic treatment combined with autotransplantation after removal of ameloblastoma

This article describes the use of indirect skeletal anchorage and autotransplantation in a patient who had an ameloblastoma removed. The mandibular left second and third molars were also extracted. Autogenous bone was grafted after surgical removal of the ameloblastoma, and the mandibular right third permanent molar was transplanted into the extraction space. Orthodontic treatment included a miniscrew to bring the transplanted tooth into good occlusion. Four years after treatment, the patient continued to show good results, with no recurrence of the ameloblastoma.

Restoration of an intruded maxillary central incisor with a uniquely designed dowel and core restoration: a case report

This article describes the restoration of an intruded root using a custom-made metal dowel and metal-ceramic veneer core restoration. The treatment plan for this patient consisted of restoring the missing esthetics and eliminating psychological trauma by utilizing the root of the intruded maxillary left central incisor to replace both missing central incisor crowns. This treatment will preserve space and bone until the patient is old enough for another prosthodontic restoration to be considered.

CLINICAL SIGNIFICANCE

As the lost fragments were not recovered, we considered this restoration of the intruded root to be the best therapeutic option, considering the effect on the patient's psyche. The patient was satisfied with the final result.

Evolution and development of Hertwig's epithelial root sheath

Periodontal regeneration and tissue engineering has re-awakened interest in the role of Hertwig's Epithelial Root Sheath (HERS), an epithelial tissue layer first discovered in amphibians more than a century ago. Using developmental, evolutionary, and cell biological approaches, we have, therefore, performed a careful analysis of the role of HERS in root formation and compared our data with clinical findings. Our developmental studies revealed HERS as a transient structure assembled in the early period of root formation and elongation and, subsequently, fenestrated and reduced to epithelial rests of Malassez (ERM). Our comparative evolutionary studies indicated that HERS fenestration was closely associated with the presence of a periodontal ligament and a gomphosis-type attachment apparatus in crocodilians and mammals. Based on these studies, we are proposing that HERS plays an important role in the regulation and maintenance of periodontal ligament space and function. Additional support for this hypothesis was rendered by our meta-analysis of recent clinical reports related to HERS function.

Tooth transplantation and cryopreservation: State of the art

Autotransplantation of teeth is useful and has many indications in dentistry. Cryopreservation of teeth creates new possibilities--eg, when autotransplantation is needed, but the recipient site is too small and orthodontic treatment is needed to gain space for the transplant. This review article examines the reactions of various dental tissues after autotransplantation vs after autotransplantation with cryopreservation. Various subjects will be discussed, including periodontal healing, pulp reactions, and root development after autotransplantation with and without cryopreservation.

Tooth transplantations: a descriptive retrospective study

The aim of the present study was to perform a retrospective study of autogeneously transplanted teeth in order to examine the influence of clinical criteria such as the type of the donor tooth, the root length at the time of transplantation, donor eruption stage and others on the overall success rate of the transplantation. The material of this study consisted of 194 patients in whom 273 teeth were transplanted. The mean age at the time of autotransplantation was 18.1 years with a standard deviation of 7.5 years. Transplantations were performed in two hospitals. The follow-up period varied from 15 days to 11 years, and the mean follow-up time was 3.8 years. 58/273 teeth showed one or other form of resorption, 37/273 teeth showed ankylosis, 30/273 showed no important changes in pulp chamber size, 104/273 showed major discoloration after transplantation, 92/273 teeth showed positive results for cold test after transplantation and 26/273 teeth showed clinically unacceptable pocket depth. Clinical and radiological evaluations were performed. An association was found between successful transplantation and donor tooth type (P<0.01), root length at the time of transplantation (P<0.0001) and recipient tooth site (P=0.03). There was a borderline association between successful transplantation and donor eruption stage (P=0.05). In conclusion, autotransplantation of teeth performed with a careful surgical procedure at the stage of 1/2-3/4 of their intended or expected root length can render a very useful service to patients.

Effect of different splinting methods and fixation periods on root development of autotransplanted immature third molars

PURPOSE

The aim of the present study was to assess the influence of suture splinting for 1 week or rigid fixation for 4 weeks on final root length, root length increment, and mobility of autotransplanted immature third molars.

PATIENTS AND METHODS

The sample consisted of 63 patients with a total of 65 transplanted immature third molars. All transplants had reached one-half (n = 29) to three-fourths (n = 36) of their expected root length. In 24 of the transplants, postoperative fixation was carried out with a rigid acid-etch composite and wire splint for 4 weeks (rigid group), and in 41 transplants, with a suture splint for 1 week (suture group). The fixation method depended on the initial stability of the transplants. All transplants were followed up clinically and radiologically for a mean period of 3.9 years.

RESULTS

Transplants in the rigid group revealed a significantly lower final root length ( P = .002) and root length increment ( P = .001) than those in the suture group. The differences were found to be more pronounced in transplants at earlier developmental stages. No differences were found in transplant mobility.

CONCLUSIONS

The results of the present study indicate that prolonged rigid fixation of autotransplanted immature third molars has a significantly negative influence on final root length and root length increment, especially in transplants at earlier developmental stages.

Auto-transplantation of central incisor with root dilaceration. Technical note

A case of central incisor with root dilaceration and ensuing impactation was treated by means of auto-transplantation. The 7-year follow-up period shows a stable result.

Influence of orthodontic derotation and extrusion on pulpal and periodontal condition of autotransplanted immature third molars

The aim of this study was to determine the influence of orthodontic treatment on the pulpal and periodontal condition of 91 transplanted immature third molars. In patients with atrophy of the alveolar process or unfavorable root morphology, transplants had to be placed in extreme rotated or infraoccluded positions. After 3 to 6 months, these transplants were derotated (45 degrees to 90 degrees) to a correct position in the dental arch (derotation group; n = 28) or extruded to the occlusal plane (extrusion group; n = 21). Finally, approximal spaces were closed in both groups. A sample of 42 transplanted third molars with no orthodontic treatment need served as the control group. All transplants were followed clinically and radiologically for a mean period of 4.0 years. With respect to pulpal and periodontal conditions, no significant differences were observed between the control and the extrusion group. In contrast, compared with the control group, transplants in the derotation group had a significantly poorer pulpal and periodontal condition. In the derotated transplants, a significant correlation was detected between pulp necrosis and orthodontic treatment of multi-rooted transplants. This study indicates that orthodontic extrusion and minor lateral movements of autotransplanted immature third molars, as well as rotation of single-rooted third-molar transplants, represent no additional risk to transplant survival. In contrast, rotation of multi-rooted transplants seems to initiate later severance of the vascular and nerval supply to the pulp.

Influence of orthodontic movement on root length of autotransplanted immature third molars

The aim of this study was to investigate the influence of orthodontic extrusion or derotation on final root length and root length increment in 75 autotransplanted immature third molars. Depending on the condition of the recipient site and the root morphology, transplants had to be placed in extreme rotated or infra-occluded position. Three to six months after transplantation, these transplants were derotated to a correct position in the dental arch (derotation group, n = 19) or extruded to the occlusal plane (extrusion group, n=18). Thirty-eight transplants with no orthodontic treatment need served as controls (control group). Transplants were followed clinically and radiologically for a mean period of 4.0 yr. No statistically significant differences were observed between the extrusion and the control groups or between the single-rooted transplants in the different groups. In contrast, multi-rooted transplants in the derotation group showed a statistically significantly shorter final root length than multi-rooted transplants in the extrusion and the control groups. However, as these differences may be considered to be of minor clinical importance (<1 mm), it can be concluded that the effect of orthodontic movement on root development of transplanted immature third molars is of only negligible clinical significance.

[Root growth after wisdom tooth transposition. Case documentation with proposal for a radiologic method to quantify growth]

OBJECTIVES

To introduce a method for assessment of root growth on panoramic radiographs exemplified by a case report on an autotransplanted lower third molar.

MATERIAL AND METHODS

A lower left third molar (T) with incomplete root formation was transplanted for replacement of the lower left first molar in an 18-year-old woman. T was monitored clinically and, together with its neighboring lower second molar (37) with constant root length, also radiographically by means of two panoramic radiographs (OPGs) produced 12 days and 20 months postoperatively. A method for calculation of the root length as a multiple of the crown length is introduced, using accurately reproducible landmarks defining the coronal and apical endpoints of the examined tooth in all OPGs of the series. This method minimizes error due to different magnifications within the set of radiographs.

RESULTS

Using the method introduced, the root length of the constant tooth 37 varied at 2.7% within the set of OPGs, whereas it revealed a 5.6% variation when the evaluation was based on direct measurement. Based on the described method, T revealed a postoperative root growth of approximately one-third of its final length and showed clinically no pathological findings during the observation period.

CONCLUSIONS

Our results indicate that with the described method root growth assessment on panoramic radiographs is more accurate than with direct measurement.

Nonprosthodontic management of alveolar clefts with 2 incisors missing on the cleft side: a report of 5 patients

A treatment combining autotransplantation of developing premolars and orthodontic space closure is described as an alternative to prosthodontics in the management of patients with alveolar clefts when 2 cleft-side incisors are missing. We report on 5 consecutive patients with unilateral clefts in whom 2 cleft-side incisors were congenitally missing, severely malformed, ectopically erupting, or lost because of trauma. In each instance, a mandibular premolar with a partly developed root was transplanted to the central incisor region (3 patients had previously undergone alveolar bone grafting). Root growth continued in all transplants. After an observation period of 2 years 6 months to 7 years 8 months, all transplanted teeth were present and fulfilled the established success criteria. The physiologic status of the transplanted premolars compared favorably with that of the central incisor on the noncleft side. The appearance of the reshaped transplants was found to match the noncleft incisor in 3 patients and deviated somewhat in 2. We concluded that an acceptable clinical outcome can be obtained by tooth transplantation combined with orthodontic space closure in patients with alveolar clefts and 2 missing cleft-side incisors.

Autotransplantation of teeth: requirements for predictable success

The aim of this article is to summarize the biologic principles required for successful autotransplantation of teeth. Indications, armamentarium, technique and prognosis will be discussed.

Reperfusion of autotransplanted teeth--comparison of clinical measurements by means of dental magnetic resonance imaging

OBJECTIVE

Dental magnetic resonance imaging (dMRI) with administration of contrast material is one method of assessing pulpal perfusion. The purpose of this study was to evaluate the level of contrast enhancement displayed by means of dMRI after transplantation of teeth and to compare these findings with the results of tooth mobility, pocket depth, cold, and electrical tests.

STUDY DESIGN

Twenty-three teeth with either complete root formation or incomplete root formation (IRF) were investigated by using dMRI and were clinically examined at intervals of 2, 4, 8, and 12 weeks, as well as 6 months and 12 months after transplantation.

RESULTS

An analysis of the enhancement in the dental images revealed a significant difference between teeth with IRF and teeth with complete root formation. In addition, the time to occurrence of a positive reaction to the cold test was significantly longer for teeth with IRF.

CONCLUSIONS

The findings of this study indicate that transplanted IRF teeth are associated with reperfusion seen by means of dMRI as well as with delayed occurrence of a positive cold test.

Conservative management of an intruded immature maxillary permanent central incisor with healing complication of pulp bone

Traumatic intrusion injury of permanent teeth is serious with multiple complications possible associated with the pulp, periodontal ligament, alveolar bone and Hertwig's epithelial root sheath. The optimal treatment for the management of an intrusion injury has not yet been determined. A case is presented involving the conservative management of an immature maxillary permanent central incisor intrusively luxated by allowing for re-eruption and orthodontic extrusion two weeks later. After a follow-up period of ten months, the intruded tooth continued to show a mobility of grade one, without metallic percussion tone or infra-occlusion, which confirmed periodontal ligament healing. Although the intruded tooth failed to respond to dry ice testing, no other signs of pulp necrosis were evident and the colour of the intruded tooth was within normal limits throughout the follow-up period. However, complications of healing of Hertwig's epithelial root sheath occurred, causing in-growth of bone and periodontal ligament into the root canal.

Eruption pattern of autotransplanted premolars visualized by radiographic color-coding

Eruption patterns and root growth were visualized with the use of a new technique, radiographic color-coding, for comparison of the development of autotransplanted premolars with contralateral control teeth. Rates of eruption and root growth were studied. The eruption pattern and rate was assessed relative to the first molar. Maximum rates were found to occur between 30 and 60 days after transplantation. There were no significant differences between transplants and their contralaterals. Two distinct categories of eruption patterns were demonstrated. One group showed a tendency toward an initial rate of transplant eruption that was somewhat faster than that of the contralaterals. The other group showed initially retarded eruption. Possible explanations were discussed. Because no significant differences between the transplants and the contralaterals were observed, it was concluded that autotransplantation is a sound treatment option for substitution of missing teeth, at least from a tooth development point of view.

Prosthetic considerations in the restoration of orthodontically treated maxillary lateral incisors to replace missing central incisors: a clinical report

The treatment of young patients with missing maxillary incisors poses a challenge to prosthodontists and orthodontists. The 2 principal treatment options are (1) the reopening or maintenance of space for future autotransplantation and/or prosthodontic restoration of the missing teeth, or (2) total orthodontic space closure, followed by prosthodontic modification of the lateral incisors to simulate the central incisors. This article discusses only the second option and describes 2 alternative methods for the modification of crown anatomy. These procedures facilitate the orthodontic closure of missing central incisor spaces to ensure satisfactory, esthetic results.

Immediate repositioning of an accidentally extruded immature premolar after extracting root remnants of the primary molar

This article describes a case where during an extraction of a primary molar's root remnant, the successor permanent tooth was accidentally extruded. The extruded tooth was immediately repositioned to its right position in the socket and it erupted normally after a short time. After 2 years, a routine clinical examination revealed normal appearance of the premolar in the dental arch. A radiograph demonstrated an obliterated coronal part of the pulp, normal root length, a slightly open apex and no periapical inflammation.

Autotransplantation of premolars to replace maxillary incisors: a comparison with natural incisors

The published literature contains no comprehensive studies that compare the outcome of premolar autotransplantation to the maxillary anterior region with natural incisors in the same patients. This article describes the gingival and periodontal conditions around premolars transplanted to the maxillary incisor region, subsequent to restoration. Forty-five premolars autotransplanted to the maxillary incisor region in 40 adolescent patients were evaluated after a mean observation period of 4.0 years. Mean age at surgery was 11.0 years. Established clinical criteria were used to assess tooth mobility, plaque and gingival indexes, probing pocket depth, and percussion. Recession and hyperplasia of interproximal gingival papillae were assessed according to a recently proposed index. Standardized radiography was used to evaluate presence of pathosis, pulp obliteration, root length, and crown-root ratios. Clinical variables for transplants did not differ from those of the natural incisors, except for increased mobility and more plaque in a few transplanted premolars. The interproximal gingival papillae adjacent to all transplanted teeth were normal or slightly hyperplastic. Radiographically, all transplants showed varying degrees of pulp obliteration, but no signs of pathosis. Crown-root ratios were similar for natural and transplanted teeth as were distances from cementoenamel junction to marginal bone. The overall status of the transplanted premolars and surrounding tissues indicated that this treatment modality may be recommended when maxillary incisors are missing in adolescents. In addition, tooth transplantation represents an inherent potential for bone induction and reestablishment of a normal alveolar process.

Treatment options for impacted teeth

BACKGROUND

A compilation of treatment options for impacted teeth is presented to assist dentists in discussing the sequelae of impacted teeth as well as the complications of treatment with their patients.

OVERVIEW

A differential diagnosis for an impacted tooth is not possible without clinical assessment. However, an ankylosed tooth or a tooth with failure of its eruption mechanism may be mistaken for an impacted tooth. This review of national and international dental texts, journals and publications concerning impacted teeth spans more than 50 years.

PRACTICE IMPLICATIONS

Treatment options for the management of impacted teeth are separated into four categories: observation, intervention, relocation and extraction. The indications, contraindications and complications of each option are presented. This information will help the clinician identify developmental conditions associated with an increased probability of tooth impaction and assess available treatment options.

Autotransplantation as a treatment option after loss of a maxillary permanent incisor tooth. A case report

A case is described of the management of a maxillary left permanent incisor, damaged by several traumatic injuries, in a 13-year-old girl. The traumatized incisor tooth required extraction and as part of an orthodontic treatment plan, a mandibular left second premolar was surgically transplanted to the prepared extraction socket at the maxillary anterior alveolus. After splinting, the transplanted tooth underwent endodontic treatment, because of pulpal necrosis. Orthodontic treatment commenced 3 months post-transplantation. Permanent root obturation was provided after orthodontic treatment and a porcelain veneer was placed to restore aesthetic appearance. The case emphasizes the importance of correct case selection, a multidisciplinary approach to treatment planning, and regular follow-up for transplanted teeth.

Autotransplantation of teeth: is there a role?

Autotransplantation of teeth, if carried out successfully, ensures that alveolar bone volume is maintained due to physiological stimulation of the periodontal ligament. Autotransplantation has been carried out for many years, but with varying success rates. As a result, it is seldom regarded as an appropriate treatment option for patients with missing teeth especially with the continued development of osseo-integrated implants. Since placement of osseo-integrated implants in growing alveolar bone is contra-indicated, transplantation of available teeth remains a suitable choice for replacing missing units in the young patient. The role of autotransplantation of teeth in several clinical situations, the clinical techniques involved and factors influencing success of the transplant are discussed. The aim of this paper is to underline the evidence based principles for successful autotransplantation and present the technique as a viable treatment option in present day orthodontic practice.

Intra-alveolar surgical uprighting of impacted teeth: a case report

Although orthodontic repositioning of impacted teeth is widely used, the treatment has its limitations. Autotransplantation or intra-alveolar surgical repositioning of teeth is an alternative therapy that may be used in selected cases of desperate impactions, when orthodontic extrusion is unsuccessful or when orthodontic treatment is rejected by the patient. A case report is presented to stress both the indications and limitations of a modified technique of intra-alveolar surgical uprighting of impacted teeth.

Pulp and periodontal healing, root development and root resorption subsequent to transplantation and orthodontic rotation: a long-term study of autotransplanted premolars

One hundred and eighteen premolars transplanted at a stage with 3/4 to 4/4 root development with a wide open apical foramen were followed with standardized clinical and radiographic techniques for signs of pulpal and periodontal ligament healing and root development. Pulp healing, evaluated first by radiographic presence of pulp canal obliteration, appeared to be an earlier sign of pulp healing than the detection of pulp vitality with an electrometric test. Continued root growth of premolars was seen in some cases. Complete arrest of root development was usually followed by development of the missing root structure at the donor site, indicating a separation of the Hertwig's epithelial root sheath. Orthodontic rotation performed on 11 premolars induced slight surface resorption and a significant shortening of tooth length (mean 1.2 mm), compared with nontreated but transplanted control teeth. However, the extent of the apical root resorption is of minor clinical importance, and is equivalent to what has been found in previous investigations of orthodontic treatment of nontransplanted premolars. Late pulp necrosis occurred in 2 of the 11 treated cases 6 years after transplantation and 5 years after orthodontic rotation. To prevent late pulp necrosis, orthodontic rotation is recommended after periodontal healing and before total pulp canal obliteration has taken place, i.e., 3 to 9 months after transplantation.

Replantation of 400 avulsed permanent incisors. 3. Factors related to root growth

Four hundred avulsed and replanted permanent incisors were examined for pulpal and periodontal healing. In 30 teeth, root formation was incomplete at the time of injury. Two teeth were excluded from the study due to nonphysiological extraalveolar storage (i.e. homemade saline). Of the 28 remaining replanted incisors, 7 showed subsequently completed root development, 8 partially completed root development and 13 arrested root development. Completed root development subsequent to replantation was found to be significantly related to pulpal revascularization, being rare in cases with pulp necrosis (5 of 15 teeth) and frequent after pulpal healing (11 of 13 teeth) (p = 0.01). Root development was not found to be significantly related to the extraalveolar storage period; but occurred slightly more frequently when the dry storage period was less than 45 min. (p = 0.13). Ingrowth of bone and formation of an internal periodontal ligament (PDL) was found in 6 teeth and was related to arrested root formation in cases with pulpal healing. The explanatory factor for these findings appeared to be damage to the Hertwig's epithelial root sheath.

Transplanting teeth successfully: autografts and allografts that work

This article suggests tooth transplantation as an alternative to other restorative options. The 10-year success rates for autografts--teeth moved from one location to another in a patient's mouth--range from 60 percent to 95 percent. Allografts, teeth moved from one person to another, are less successful. The authors report on one case of each type of transplant.

Replantation of 400 avulsed permanent incisors. 1. Diagnosis of healing complications

A material of 322 patients with 400 avulsed and replanted permanent teeth were followed prospectively in the period from 1965 to 1988 (mean observation period = 5.1 yrs). The age of the patients at the time of replantation ranged from 5 to 52 yrs (mean = 13.7 yrs and median = 11.0 yrs). Standardized patient records were used through the entire period in order to obtain valid data concerning the extent of injury and treatment provided. At the follow-up period, pulpal and periodontal healing were monitored by clinical examination, mobility testing and standardized radiographic controls. Thirty-two of the replanted teeth (8%) showed pulpal healing. When related to teeth with incomplete root formation, where pulpal revascularization was anticipated (n = 94) the frequency of pulpal healing was 34%. Periodontal ligament healing (i.e. with no evidence of external root resorption) was found in 96 teeth (24%). Gingival healing was found in 371 teeth (93%). During the observation period, 119 teeth (30%) were extracted. Tooth loss was slightly more frequent in teeth with incomplete root formation at the time of replantation than in teeth with completed root formation.

Indications of autotransplantation of teeth in orthodontic problem cases

Autotransplantations of teeth have been widely used in orthodontics, mainly in cases of severe impactions, early loss of permanent teeth, or congenital aplasia. In specific clinical situations, indication of extractions or supernumerary teeth may provide donor teeth for transplantations avoiding prosthetic or implant therapy. Two cases are presented to illustrate the topic, and prognostic factors of autotransplantation are discussed.

Autotransplantations and loss of anterior teeth by trauma

The loss of anterior teeth by trauma has usually been corrected by orthodontic or prosthetic means. In some specific cases, however, the skeletal and dental relationship may contraindicate the use of space-closure mechanics. Autotransplantation of teeth, successfully depicted in many clinical studies, can help to reduce the severity of orthodontic cases complicated by traumatized anterior teeth. A case report is presented to stress both the indications and limitations of such treatment.

Long-term clinical and radiologic evaluation of autotransplanted teeth

The purpose of the present study was to investigate the radiologic results of 40 autotransplantations (20 molars and 20 premolars) performed in the orthodontic department of the University of Geneva between 1979 and 1990. The sample demonstrated persistence of pulp vitality and continuous root development, followed, however, in most cases by replacement root resorption. The data were in accordance with previously published studies and point to an ideal developmental stage for molar and premolar transplantation to ensure pulpal and periodontal survival.

Treatment of traumatic dental injuries. Shift in strategy

A more conservative approach to the treatment of traumatic dental injuries has been made possible by knowledge concerning the pathogenesis of external root resorption, increased knowledge about wound healing processes in the pulp and periodontium, as well as by advances in restorative dentistry (reattachment of crown fragments with a dentin bonding system, the use of adhesive bridges, and advances in autotransplantation and implantation). However, a rethinking by the public, clinicians, and third-party payers is necessary for these procedures to gain wider acceptance. The present article describes the state of the art of treating dental trauma in the hope that these advances can become an accepted part of the dental trauma armamentarium and not merely scientific curiosities.