Autotransplantation and replantation of tooth germs in monkeys. Effect of damage to the dental follicle and position of transplant in the alveolus

Multimodal Imaging of Dental Pulp Healing Patterns following Tooth Autotransplantation And Regenerative Endodontic Treatment

INTRODUCTION

Understanding the healing process of dental pulp after tooth autotransplantation (TAT) and regenerative endodontic treatment (RET) of immature teeth is important both clinically and scientifically. This study aimed to characterize the pattern of dental pulp healing in human teeth that underwent TAT and RET using state-of-the-art imaging techniques.

MATERIALS AND METHODS

This study examined four human teeth, two premolars that underwent TAT and two central incisors that received RET. The premolars were extracted after one year (case 1) and two years (case 2) due to ankylosis, while the central incisors were extracted after three years (cases 3 and 4) for orthodontic reasons. Nanofocus x-ray computed tomography was used to image the samples before being processed for histological and immunohistochemical analysis. Laser scanning confocal second harmonic generation imaging (SHG) was used to examine the patterns of collagen deposition. A maturity-matched premolar was included as a negative control for the histological and SHG analysis.

RESULTS

Analysis of the four cases revealed different patterns of dental pulp healing. Similarities were observed in the progressive obliteration of the root canal space. However, a striking loss of typical pulpal architecture was observed in the TAT cases, while a pulp-like tissue was observed in one of the RET cases. Odontoblast-like cells were observed in cases 1 and 3.

CONCLUSION

This study provided insights into the patterns of dental pulp healing after TAT and RET. The SHG imaging sheds light on the patterns of collagen deposition during reparative dentin formation.

Influence of Static Navigation Technique on the Accuracy of Autotransplanted Teeth in Surgically Created Sockets

The aim of this study was to analyse and compare the position of single-rooted autotransplanted teeth using computer-aided SNT drilling and conventional freehand (FT) drilling, by comparing the planned and performed position at the coronal, apical and angular level. Materials and methods: Forty single-root upper teeth were selected and distributed into the following study groups: A. Autotransplanted tooth using the computer-aided static navigation technique (SNT) (n = 20) and B. Autotransplanted tooth using the conventional free-hand technique (FT) (n = 20). Afterwards, the teeth were embedded into two experimental models and 10 single-root upper teeth were randomly autotransplanted in each experimental model. The experimental models were submitted to a preoperative cone-beam computed tomography (CBCT) scan and a digital impression by a 3D intraoral scan, in addition to a postoperative CBCT scan, after the autotransplantation. Datasets from postoperative CBCT scans of the two study groups were uploaded to the 3D implant planning software, aligned with the autotransplantation planning, and the coronal, apical and angular deviations were measured. The results were analysed using Student’s t-test and Mann–Whitney non-parametric statistical analysis. Results: Coronal (p = 0.079) and angular (p = 0.208) statistical comparisons did not present statistically significant differences; however, statistically significant differences between the apical deviation of the SNT and FT study groups (p = 0.038) were also observed. Conclusions: The computer-aided static navigation technique does not provide higher accuracy in the positioning of single-root autotransplanted teeth compared to the conventional free-hand technique.

Autotransplantation of the Third Molar: A Therapeutic Alternative to the Rehabilitation of a Missing Tooth: A Scoping Review

INTRODUCTION

Tooth autotransplantation is the repositioning of an erupted, partially erupted, or non-erupted autologous tooth from one site to another within the same individual. Several factors influence the success rate of the autotransplant, such as the stage of root development, the morphology of the tooth, the surgical procedure selected, the extraoral time, the shape of the recipient socket, the vascularity of the recipient bed, and the vitality of the cells of the periodontal ligament. The aim of this scoping review was to provide the most up-to-date information and data on the clinical principles of the third-molar autograft and thus provide clinical considerations for its success.

MATERIALS AND METHODS

This review was conducted based on PRISMA-ScR (Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews). The research was conducted by searching for keywords in three databases-PubMed, Scopus and Google Scholar-by two independent reviewers following the PRISMA protocol, from which 599 records were identified.

CONCLUSIONS

Third-molar autotransplantation is a valid solution to replace missing teeth. The key to the success of this technique is the surgical procedure, which must be as atraumatic as possible to preserve the periodontal ligament of the tooth to be transplanted. The success rate is also linked to the stage of development of the root, with a worse prognosis in the case of a complete root.

Guided tooth autotransplantation in edentulous areas post-orthodontic treatment

OBJECTIVE

Tooth autotransplantation with a complete root formation to replace one or more lost teeth is indicated as a cost-effective alternative to implants. The aim of this case report was to describe a successfully guided autotransplantation of a maxillary third molar with fully formed roots into a surgically created socket after orthodontic space opening.

CLINICAL CONSIDERATIONS

A guided autotransplantation of the maxillary left third molar into the missing maxillary left first molar site was chosen. After virtually orientating donor tooth to confirm its optimum fit, it was deemed necessary to open 4 mm the mesiodistal space. Following the orthodontic movement, a 3-dimensional (3D)-guiding template and a milled surgical guide were manufactured to allow the donor tooth to be transplanted exactly in the planned position. The 2-year follow-up periapical radiograph showed a continuous periodontal space with no signs of apical periodontitis or root resorption.

CONCLUSIONS

Virtual planning and 3D-printed tooth replica combined with guided surgery can simplify the autotransplantation technique for both the clinician and the patient, particularly when the socket has been completely created during surgery.

CLINICAL SIGNIFICANCE

Virtual digital planning, which can accurately calculate the exact space to open orthodontically before an autotransplantation, could prove essential to enhancing the precision of 3D placement of the donor tooth in the recipient site.

A conservative approach for an adult patient with a fractured tooth and crowding: Autotransplantation at the fracture site

Autotransplantation of a mature premolar in adults can be a treatment of choice for tooth replacement when combined with well-planned orthodontic treatment. This case report describes the successful treatment of a 39-year-old patient with severe crowding and a hopelessly fractured tooth on the maxillary left side. Maxillary dental crowding was relieved by extraction of a premolar on the right side, and this extracted tooth was autotransplanted to replace the fractured tooth. A mandibular incisor was extracted to correct anterior crossbite. The total treatment period was 20 months. The treatment results showed a good long-term prognosis after transplantation of a mature premolar with normal surrounding alveolar bone level for over 6 years of follow-up. Occlusion and periodontal health were excellent in the long term.

Autotransplantation of immature third molars using a computer-aided rapid prototyping model: a report of 4 cases

INTRODUCTION

Autotransplantation of immature teeth can be an option for premature tooth loss in young patients as an alternative to immediately replacing teeth with fixed or implant-supported prostheses. The present case series reports 4 successful autotransplantation cases using computer-aided rapid prototyping (CARP) models with immature third molars.

METHODS

The compromised upper and lower molars (n = 4) of patients aged 15-21 years old were transplanted with third molars using CARP models. Postoperatively, the pulp vitality and the development of the roots were examined clinically and radiographically. The patient follow-up period was 2-7.5 years after surgery.

RESULTS

The long-term follow-up showed that all of the transplants were asymptomatic and functional. Radiographic examination indicated that the apices developed continuously and the root length and thickness increased. The final follow-up examination revealed that all of the transplants kept the vitality, and the apices were fully developed with normal periodontal ligaments and trabecular bony patterns.

CONCLUSIONS

Based on long-term follow-up observations, our 4 cases of autotransplantation of immature teeth using CARP models resulted in favorable prognoses. The CARP model assisted in minimizing the extraoral time and the possible Hertwig epithelial root sheath injury of the transplanted tooth.

Pulp and periodontal tissue repair - regeneration or tissue metaplasia after dental trauma. A review

Healing subsequent to dental trauma is known to be very complex, a result explained by the variability of the types of dental trauma (six luxations, nine fracture types, and their combinations). On top of that, at least 16 different cellular systems get involved in more severe trauma types each of them with a different potential for healing with repair, i.e. (re-establishment of tissue continuity without functional restitution) and regeneration (where the injured or lost tissue is replaced with new tissue with identical tissue anatomy and function) and finally metaplasia (where a new type of tissue replaces the injured). In this study, a review is given of the impact of trauma to various dental tissues such as alveolar bone, periodontal ligament, cementum, Hertvigs epithelial root sheath, and the pulp.

Characterization of dentin formed in transplanted rat molars by electron probe microanalysis

The present study was designed to characterize dentin formed in transplanted rat molars by investigating calcium (Ca), phosphorus (P), and magnesium (Mg) concentrations using electron probe microanalysis (EPMA) as well as examining the rate of dentin matrix formation by vital staining. The unerupted immature lower right second molar in 2-week-old rats was transplanted into the upper right first molar socket. Rats were injected with oxytetracycline, calcein, and alizarin intraperitoneally at 1 day before and 1 and 2 weeks after transplantation, respectively, for vital staining. The maxillae and mandibles were fixed 3 weeks after transplantation, resected, and embedded in resin. Undemineralized sections were cut and examined by fluorescent microscopy and EPMA. The thickness of dentin formed in the first week after transplantation was significantly less than that of dentin formed in any other 1-week period in the transplanted tooth and was about one-fifth the thickness of dentin formed in control teeth. Formation of dentin recovered in the third week after transplantation. In the first week after transplantation, EPMA demonstrated a sharp increase in Mg concentration with a slight decrease in Ca concentration. Thereafter, no significant difference was identified among Ca, P, or Mg concentrations or the Ca/P ratio between transplanted and control teeth. These results suggest that disruption of the circulation and innervation by transplantation cause a temporary change in the matrix formation rate and elemental distribution of dentin, which is subsequently restored within 2 weeks after transplantation.

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.

Autotransplantation of immature third molars into edentulous and atrophied jaw sections

The aim of the present study was to assess the results after transplantation of 85 immature third molars. Recipient site conditions varied and different surgical techniques were used. The long-term results after preparation of a new alveolus, splitting osteotomy of the alveolar process or use of free bone autografts were compared with the results after transplantation into a fresh extraction site (control group). Transplantations into prepared sockets showed equal results to the control group (94% respectively). Transplantations in connection with free bone autografts (84%) or after splitting osteotomy of the alveolar process (63%) showed poorer success rates, the differences between the latter and the control group being statistically significant. A possible correlation to revascularization disturbances of the pulp due to an insufficiency of the recipient site or to postoperative infection is suspected. The results show that transplantation of immature third molars is a safe, useful procedure when appropriate conditions of the recipient site are present. Where the alveolus is atrophic, a splitting osteotomy should be performed only in exceptional cases and preference should be given to alternative methods such as primary bone augmentation or bone-regenerative procedures.

Autotransplantation of immature third molars: influence of different splinting methods and fixation periods

Different data were published documenting the influence of fixation methods and periods on the outcome of autotransplantations of teeth. Besides studies reporting increased ankylosis and disturbances of pulpal revascularization following rigid or extended fixation, there are studies revealing no connection in this matter. The clinical and radiological results of 76 transplanted germs of third molars were to be assessed after a rigid fixation for 4 weeks or after a suture splinting for 7 days and compared with each other. The choice of fixation method depended on the initial stability of the transplant. After a mean observation period of 3.4 years (range 1.0-6.1 years), 92.9% of the teeth stabilized with a suture, but only 73.5% fixed with an acid-etch composite and wire splint could be classified as successful (P = 0.029). The significant increases in ankylosis (P = 0.036) and pulp necrosis (P = 0.041) were the factors for the less favorable results of the rigidly fixed teeth. Our data support the results of other experimental and clinical studies with regard to the negative influences of an extended and rigid fixation on the success of tooth transplantation. However, apart from a correlation with the method and period of fixation, we also suspect the influence of an incongruity between the transplant and recipient site.

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.

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.

Tooth eruption: theories and facts

The mechanisms of tooth eruption (i.e., the answer to the question of how and why teeth erupt) has been a matter of long historical debate. This review focuses on human and other mammalian teeth with a time- and spacewise limited period of eruption and analyzes recent observations and experimental data on dogs, rats, primates, and humans in a framework of basic biological parameters to formulate a guiding theory of tooth eruption. Acknowledging basic parameters (i.e., that teeth move in three-dimensional space, erupt with varying speed, and arrive at a functional position that in inheritable) eliminates a number of previously held theories and favors those that accommodate basic parameters, such as alveolar bone remodeling in association with root elongation, with possible correction factors in the form of cementum apposition and periodontal ligament formation. We have critically analyzed, summarized, and integrated recent findings associated with preeruptive movements of developing teeth, the intraosseous stage of premolar eruption in dogs, molar eruption in rodents, and premolar and molar eruption in primates. The variable speeds of eruption are particularly important. We conclude with basic principles of tooth eruption--that is, the type of signals generated by the dental follicle proper, the conditions under which teeth are moved and the clinical understanding to be derived from this knowledge.

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.

The basic and applied biology of tooth eruption

The dentition and the alveolar process of each jaw develop simultaneously so that, by the time the crown is completed and eruption begins, the crown is enclosed in a crypt within alveolar bone. Thus, the eruption of a tooth to its functional position involves discretely localized, bilaterally symmetrical bone resorption to produce an eruption pathway and bone formation to fill in the space previously occupied by the crown and growing roots. Studies of crypt surfaces during eruption confirm this polarization of alveolar bone metabolism around a tooth with respect to both bone cells and mineralized surface topography. Experimental studies of tooth eruption have shown that the dental follicle, the dense connective tissue investment of the tooth, is necessary for eruption and that neither bone resorption nor bone formation occur without the adjacent part of the dental follicle. Early in eruption the coronal part of the follicle accumulates mononuclear cells which have cytochemical and ultrastructural features of osteoclasts and the apical part of the follicle, a site of intense cell proliferation, binds epidermal growth factor (EGF). The dental follicle contains a variety of proteins and the concentration of several change during eruption. Prominent among them are a reduction in matrix metalloproteinases and an increase in protoglycans as eruption proceeds. The contribution of these changes to those in cell proliferation, migration and differentiation during tooth eruption present experimental opportunities for developmental biologists. The rate-limiting factor of the earliest (intraosseous) stage of tooth eruption is bone resorption and eruption can be accelerated or retarded by the local delivery of factors which increase or decrease the activity of osteoclasts.(ABSTRACT TRUNCATED AT 250 WORDS)

A clinical and radiologic study of autotransplanted impacted canines

The aim of the present study was to evaluate the clinical and radiologic results of 20 autotransplantations of impacted canines performed in the Orthodontic and Pedodontic Department of the University of Geneva between 1979 and 1988. The sample, divided into two different age groups (group A: 13-20 years; group B: 20-48 years), demonstrated persistence of pulp vitality in 80% of the cases in group A, whereas routine endodontic treatment was instituted in all cases of group B. Periodontal healing was noted in 90% of the cases in group A, and in 70% of the cases in group B. The present clinical and radiologic data indicate that impacted canines can be transplanted at any age with good prognosis and are an alternative to orthodontic repositioning in selected cases of canine impaction.

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.

Current concepts of the biology of tooth eruption

Tooth eruption is defined as the movement of a tooth from its site of development within the jaws to its position of function within the oral cavity. We present a critical review of evidence for the mechanisms and regulation of the intraosseous and supraosseous phases of eruption, with an emphasis upon the canine premolar model studied by the authors. Analyses at different stages of premolar eruption indicate that selective fragmentation of dental follicle protein DF-95 correlates with the presence of elevated levels of follicular collagenase and stromelysin, and with the onset of premolar movement. A dramatic decrease in these metalloproteinases followed initiation of movement. A biochemical and cell biological model for regulation of tooth eruption is proposed based upon these new and existing data.

Autotransplantation of premolar teeth to replace missing maxillary central incisors

Orthodontic treatment decisions when maxillary central incisors are absent or are of poor prognosis, are discussed. Autotransplantation of mandibular first premolars to the incisor region is suggested as an approach in selected cases. The literature is reviewed, surgical technique described and case selection summarized. Cases are reported where autotransplantation of premolars to the maxillary incisor region has produced good functional and aesthetic results.

Re- and allotransplantation of teeth--an experimental study in monkeys

In each of six monkeys one of the permanent lateral incisors with uncompleted root development was replanted. At the same time the contralateral incisors in four of the monkeys were allotransplanted by pairs. The remaining two contralateral incisors served as controls. After 4 weeks and 4 months, respectively, three monkeys were decapitated and the upper lateral incisors with adjacent periodontal tissue were examined histologically. The replanted teeth in five cases had a vital pulp. In the sixth case, however, the replanted incisor exhibited pulpitis and partial necrosis of the pulp. The periodontal membrane had a normal histologic appearance. In two cases a small area of arrested root resorption was observed. With the allotransplanted teeth the histologic appearance was altered. After 4 weeks a pronounced inflammatory reaction was observed in both the pulpal tissue and the periodontal membrane. The pulp was in most cases necrotic, and marked root resorption was observed. Most of the allotransplanted teeth were resorbed and replaced by an irregular hard tissue that resembled osteoid, which in many cases was connected with the tooth remnants by ankylosis. These results indicate that allotransplanted teeth, in contrast to replanted teeth, exhibit the characteristic features of an allograft rejection, including an inflammatory reaction and resorption.

Development of a tooth germ within an autogenous clavicular graft

The left side of the mandible distal to the second primary molar of a 3 years old Southern Chinese boy was resected as a result of osteomyelitis. A diaphyseal clavicular graft pedicled on the sternomastoid muscle was selected for the reconstruction of the mandible. By the age of 6 years, the mandible although stunted in size did exhibit appropriate remodelling. In addition a tooth germ in the region of the second permanent molar was found developing in the autogenous bone graft of the mandible.

Regional control by the dental follicle of alterations in alveolar bone metabolism during tooth eruption

Tooth eruption is a localized, bilaterally symmetrical series of events which involves resorption and formation of alveolar bone on opposite sides of the tooth and requires the presence of the dental follicle. We examined the effect on eruption of selective surgical removal of parts of the follicle. Removal of either the basal or coronal halves of the follicle prevented eruption. Bone resorption and formation of an eruption pathway did not occur after removal of the coronal part of the follicle and bone formation did not occur after removal of the basal part of the follicle. Exposure and incisions of the follicle had no effect on eruption. We interpret these data to mean that the polarized resorption and formation of alveolar bone that occur around a tooth during eruption are regulated by the adjacent parts of the dental follicle.

Evaluation of over 400 autogenous tooth transplants

Results are described from a series of over 400 autogenous tooth transplants that have been followed up for two years or longer. A success rate of over 70% is reported.

Autotransplantation of human premolars. A clinical and radiographic study of 100 teeth

The purpose of the present study was to identify factors which might influence the success of autotransplantation, such as root development, root resorption, pulp condition and tooth eruption. The material consisted of 100 human premolars transplanted in 87 patients. The observation period ranged from 3-18 years, with a mean value 6.3 years. Clinical and radiographic examinations were performed. The transplanted premolars were divided into 7 stages of root development. At the final control, 93 teeth remained and 7 teeth were extracted. Periodontal healing without root resorption was related to stage of root development. It decreased from 93% in teeth with 3/4 root development to 37% in teeth with fully developed roots. Inflammatory root resorption was seen in 7 cases and replacement root resorption in 12 cases. Pulp revascularization was observed in 100% in stages with initial root development to 1/2 root development and decreased to 0% for teeth with fully developed roots. Pulp obliteration was observed in all cases with revascularized pulp tissue. The gingival condition was similar to contralateral, not transplanted premolars or adjacent teeth. Root growth increased with the stage of root development at the time of transplantation. It is concluded that transplantation of premolars with 1/2-3/4 root development provides a good chance of pulp survival, limited risk of root resorption and ensures sufficient final root length, and is thus recommended.