Autotransplantation of teeth in 215 patients. A follow-up study

Extracellular Matrix Revisited: Roles in Tissue Engineering

The extracellular matrix (ECM) is a heterogeneous, connective network composed of fibrous glycoproteins that coordinate in vivo to provide the physical scaffolding, mechanical stability, and biochemical cues necessary for tissue morphogenesis and homeostasis. This review highlights some of the recently raised aspects of the roles of the ECM as related to the fields of biophysics and biomedical engineering. Fundamental aspects of focus include the role of the ECM as a basic cellular structure, for novel spontaneous network formation, as an ideal scaffold in tissue engineering, and its essential contribution to cell sheet technology. As these technologies move from the laboratory to clinical practice, they are bound to shape the vast field of tissue engineering for medical transplantations.

Stability determinants of bone-borne force-transmitting components in three RME hybrid expanders-an in vitro study

BACKGROUND

The aim was to test which component [wire arm, connecting abutment attachment, and orthodontic mini-implant (OMI)] of the force-transmitting system (FTS) in the anterior palate of three commonly used hybrid expanders (HEs; WILMES-HE, LUDWIG-HE, and WINSAUER-HE) deforms under increasing load.

MATERIALS AND METHODS

Crude single and double wire arms were tested individually. Non-opening of the maxillae halves was simulated in artificial bone blocks with single wire and double wire FTS specimens. OMIs were inserted 8mm and underwent 6mm of continuous static lateral loading. Deformation angles were measured (X-ray, n = 6) at 0, 3 and 6mm feed. OMIs and abutments were scan electron microscope (SEM) evaluated.

RESULTS

After 1.0mm of loading, the single wire arm of all FTS deformed between 63.4 (16.5) N and 76.2 (18.4) N, and the double wire arm of reinforced FTS (wires positioned 'side by side') deformed after 1.0mm between 110.0 (18.4) N and 134.8 (22.3) N. The crude single wire resisted 89 (5.1) N until plastic deformation, whereas the crude double wire positioned 'on top of each other' resisted 438 (21.3) N. At 6mm loading, the reinforced WINSAUER-HE FTS withstood a maximum load of 320.9 (31.1) N and the reinforced LUDWIG-HE FTS 19% less, both under great deformation of double wires and OMIs. The screw-fixated WILMES-HE FTS abutment attachment (overlapping OMI head 34%) detached around 250N. The bonded WINSAUER-HE and LUDWIG-HE abutment attachments did not detach. Nor did the modified bonded plus the modified screw-fixated WILMES-HE abutment attachment when overlapping 100%.

CONCLUSION

Early OMI and single wire arm deformation in HEs are crucial for unsuccessful RME in more mature maxillae. Double wire arms should be obligatory. OMIs with inner diameter greater 1.36mm are recommended. One hundred per cent overlapping abutment attachments do not detach.

Autotransplantation of Premolars With a 3-Dimensional Printed Titanium Replica of the Donor Tooth Functioning as a Surgical Guide: Proof of Concept

PURPOSE

Autotransplantation of premolars is a good treatment option for young patients who have missing teeth. This study evaluated the use of a preoperatively 3-dimensional (3D)-printed replica of the donor tooth that functions as a surgical guide during autotransplantation.

MATERIALS AND METHODS

Five consecutive procedures were prospectively observed. Transplantations of maxillary premolars with optimal root development were included in this study. A 3D-printed replica of the donor tooth was used to prepare a precisely fitting new alveolus at the recipient site before extracting the donor tooth. Procedure time, extra-alveolar time, and number of attempts needed to achieve a good fit of the donor tooth in the new alveolus were recorded.

RESULTS

For each transplantation procedure, the surgical time was shorter than 30 minutes. An immediate good fit of the donor tooth in the new alveolus was achieved with an extra-alveolar time shorter than 1 minute for all transplantations.

CONCLUSION

These results show that the extra-alveolar time is very short when the surgical guide is used; therefore, the chance of iatrogenic damage to the donor tooth is minimized. The use of a replica of the donor tooth makes the autotransplantation procedure easier for the surgeon and facilitates optimal placement of the transplant.

Orthodontic Microimplants Assisted Intrusion of Supra-erupted Maxillary Molar Enabling Osseointegrated Implant Supported Mandibular Prosthesis: Case Reports

Loss of mandibular molars, when not replaced in time, are usually associated with overeruption of maxillary molars. To provide prosthetic replacement for missing lower posteriors, over erupted maxillary teeth have been intruded in past with great difficulty in adults with conventional orthodontics, along with associated problems of root resorption. Currently orthodontic microimplants provide stable intraoral anchorage, allow predictable maxillary molar intrusion enabling reestablishment of functional posterior occlusion with mandibular implant supported prosthesis, thereby reducing need for prosthetic crown reduction in maxillary arch. The added advantage of microimplant is it enables use of sectional appliance in area of concern instead of full arch bracketed appliance which an adult may not accept. The case reports demonstrates, overerupted maxillary molars were intruded using orthodontic microimplants to enable prosthetic rehabilitation of mandibular dentition by osseointegrated implant supported prosthesis. The second case report also demonstrates use of CBCT scan in planning and execution.

Evaluating success of autotransplantation of embedded/impacted third molars harvested using piezosurgery: a pilot study

OBJECTIVE

To evaluate the success of autogenous transplantation of embedded/impacted third molars harvested using piezosurgery.

MATERIALS AND METHODS

This prospective pilot study enrolled 20 healthy patients with non-restorable first/second molars and a caries-free retrievable embedded/impacted third molar. Piezosurgery was used for removing inter-radicular bone at the recipient socket as well as for bone removal around the donor teeth.

RESULTS

After an average follow-up of 16.4 months (SD = 1.9), 18 cases were successful with formation of periodontal ligament around the teeth. One tooth was lost due to infection at 1 month. One patient was lost to follow-up. There was no root resorption or ankylosis in any of the cases. In six donor teeth with complete root formation, root canal treatment was carried out. All the remaining teeth responded positively with vitality testing.

CONCLUSION

Piezosurgery is an effective device if embedded/impacted third molars are to be harvested for successful autogenous transplantation.

Successful autotransplantation of a mature mesiodens to replace a traumatized maxillary central incisor

AIM

This case describes the successful transplantation of a mature mesiodens tooth to replace a traumatized maxillary central incisor.

SUMMARY

A 17-year-old male attended 1 week after a traumatic injury to his left maxillary central incisor (tooth 21). Radiographs revealed a horizontal root fracture and a poor prognosis. The tooth was atraumatically removed and replaced with a mesiodens lying in the same region. After stabilization, root canal treatment was performed and aesthetics were restored with a tooth coloured restoration. A 2-year follow-up revealed the tooth had good aesthetics and function.

KEY LEARNING POINTS

A supernumerary nonfunctional tooth such as a mesiodens can be successfully used to replace a missing permanent tooth by autotransplantation. Autotransplantation has a high success rate if case selection is good, appropriate surgery is carried out and excellent hygiene is maintained. Autotransplantation should be considered as one of the most biologic techniques for replacing a missing tooth with minimal cost. Autotransplantation can be carried out even after complete root formation in the donor tooth.

Survival rate in autotransplanted premolars with complete root formation: a retrospective clinical survey

The purpose of this study was to analyze the survival rate in autotransplanted premolars with complete root formation in dental clinics. Participating dentists were requested to provide information on transplantations they had undertaken between 1 January 1990 and 31 December 2010. Data on a total of 708 teeth from 637 patients were collected. Data for other tooth types and for teeth with incomplete root formation were eliminated. In this study, data on 40 teeth in 35 patients were analyzed. Participants consisted of 17 men and 18 women ranging from 24 to 79 years in age (mean age, 43.7 years). The cumulative survival rate was 100% at the 5-year mark and 72.7% at 10 years, as calculated by the Kaplan-Meier method. Single-factor analysis revealed that "transplanted to the molar regions" was a significant risk factor (p<0.05) influencing the survival of transplanted teeth. However, a Cox regression analysis showed no significance. The results of this study suggest that, in cases where there is a suitable donor tooth and the oral condition is good, premolar autotransplantation is a viable treatment option, even when there is complete root formation in the donor teeth.

Autotransplantation of mesiodens for missing maxillary lateral incisor with cone-beam CT-fabricated model and orthodontics

AIM

Autotransplantation is a viable treatment option for a missing tooth when there is a suitable donor, especially in adolescents with remaining facial growth. This report presents the aesthetic restoration of a missing maxillary lateral incisor through orthodontic treatment and autotransplantation of a mesiodens using a CBCT-fabricated rapid-prototyping model.

SUMMARY

A 14-year-old male patient with a congenitally missing maxillary lateral incisor was referred from the Department of Orthodontics. The teeth were moved orthodontically to regain space for the missing lateral incisor and to close the space of the mesiodens after transplantation. A replica of the donor tooth was fabricated from a cone-beam computed tomography scan through a rapid-prototyping machine before autotransplantation surgery. The model was used to create a socket for the graft tooth, thereby shortening the extra-oral time and minimizing the damage to the root surface. After transplantation and orthodontic tooth movement, the mesiodens was finally restored with an aesthetic laminate restoration. Over 3 years, the aesthetics remained excellent, and the transplant functioned normally without any signs or symptoms of root resorption.

KEY LEARNING POINT

Missing anterior teeth may be replaced through a combination of orthodontics, autotransplantation with a rapid-prototyping model and prosthodontic restoration, in growing patients.

Autotransplantation and surgical uprighting of impacted or retained teeth: A retrospective clinical study and evaluation of patient satisfaction

OBJECTIVES

This retrospective clinical study aimed to determine the success rate of autotransplanted impacted or retained teeth along with a patient satisfaction survey and to analyze the influence of relevant clinical and radiographic parameters.

SUBJECTS AND METHODS

Fifty-seven teeth (37 canines, 10 molars, seven premolars, three incisors) in 45 patients (median 15 years) were evaluated over a mean of 1.6 years. The success criteria were pocket probing depth ≤3.5 mm, mobility grade ≤ II, Periotest ≤30 and complete alveolar bone healing. The influencing parameters were oral hygiene, smoking, periodontal screening index, occlusal/proximal contacts, horizontal position, dental age, pulp obliteration and degree of displacement. Furthermore, bone height was measured.

RESULTS

The overall success rate was 74%, along with a high patient satisfaction. The survival rate was 96% after a mean follow-up of 1.6 years. The favorable factors were proper oral hygiene, non-smoking, good general periodontal condition, proximal contacts and pulp obliteration. An increase in or maintenance of bone level was found in 96%.

CONCLUSIONS

Autotransplantation of impacted or retained teeth is an appropriate treatment, if orthodontic alignment has failed, especially in growing patients.

Autotransplantation of a Mandibular Third Molar: A Case Report with 5 Years of Follow-up

This paper describes the autologous transplantation of a mandibular right third molar to replace the residual roots of the second molar in the same quadrant, preserving function and aesthetics. A 5-year clinical and radiographic follow-up was undertaken. After transplantation, the donor tooth received endodontic treatment and placement of calcium hydroxide, which was periodically replaced every 3 months until the filling of the root canals, totalizing a period of 1-year, when apical closure was confirmed. The tooth was in perfect functional and aesthetic conditions 5 years after beginning of treatment. Autotransplantation is a feasible option for replacing missing teeth when a donor tooth is available. The autotransplantation of a right mandibular third molar with compromised function and aesthetics to replace the residual roots resulting from coronal destruction due to extensive carious lesion of the second molar in the same quadrant was a viable treatment alternative.

Gender difference in tooth autotransplantation with complete root formation: a retrospective survey

Gender-related risk factors in the survival of transplanted teeth with complete root formation have not yet been identified. The purpose of this study was to investigate gender differences in tooth autotransplantation at dental clinics. We asked participating dentists to provide information on transplantations they had undertaken from 1 January 1990 to 1931 December 2010. The data were screened to exclude patients who underwent more than one transplantation, smokers or those whose smoking habits were unknown, patients under 30 or who were 70 years old and over, cases where the transplanted teeth had incomplete root formation or multiple roots and those with fewer than 20 present teeth post-operation. We analysed 73 teeth of 73 males (mean age, 47.2 years) and 106 teeth of 106 females (mean age, 45.3 years) in this study. The cumulative survival rate and mean survival time were calculated using the Kaplan-Meier method. The cumulative survival rate for males was 88.3% at the 5-year mark, 64.8% at 10 years and 48.6% at 15 years; for females, it was 97.2% at the 5-year mark, 85.9% at 10 years and 85.9% at 15 years. A log-rank test indicated the difference between males and females to be significant (P = 0.011). There was also a significant difference in the main causes for the loss of transplanted teeth: males lost more transplanted teeth due to attachment loss than females (P < 0.05). These results indicate that males require more attention during the autotransplantation process, particularly at the stage of pre-operation evaluation and that of follow-up maintenance.

Autotransplantation of a supernumerary tooth to replace a misaligned incisor with abnormal dimensions and morphology: 2-year follow-up

Autotransplantation is a viable treatment option to restore esthetics and function impaired by abnormally shaped teeth when a suitable donors tooth is available. This paper describes the autotransplantation and 2-year follow-up of a supernumerary maxillary incisor as a replacement to a misaligned maxillary incisor with abnormal crown morphology and size. The supernumerary incisor was immediately autotransplanted into the extraction site of the large incisor and was stabilized with a bonded semirigid splint for 2 weeks. Fixed orthodontic therapy was initiated 3 months after autotransplantation. Ideal alignment of the incisors was accomplished after 6 months along with radiographic evidence of apical closure and osseous/periodontal regeneration. In autogenous tooth transplantation, a successful clinical outcome can be achieved if the cases are selected and treated properly.

Insertion torque, pull-out strength and cortical bone thickness in contact with orthodontic mini-implants at different insertion angles

This study aimed to evaluate biomechanical behaviour of inclined orthodontic mini-implants by analyzing its insertion torque (IT), axial pull-out strength (APS), and cortical bone thickness in contact with mini-implant (CBTC). A total of 102 mini-implants were inserted at 90 degree, 60 degree, and 45 degree to the surface of synthetic bone. Peak IT was measured, and the mini-implants were aligned with the mechanical testing machine to record the APS. The cortical bone thickness in contact with each mini-implant was measured after the pull-out test and the data were subjected to statistical analyses. The 45 degree group had a significantly higher IT compared with the 90 degree group (P < 0.05). There was a statistically significant increase in the average of cortical bone thickness in CBTC across the three groups (P < 0.05). A negative correlation between the angulation and the CBTC (r = -0.95, P < 0.05) and a positive correlation between the APS and the CBTC were observed (r = 0.34, P < 0.05). Mini-implants that are inserted more inclined to the surface of the bone provide greater IT and an increased contact with the cortical bone. The greater the CBTC, the greater is the APS.

Therapeutic decisions in the presence of decayed permanent first molars in young subjects: a descriptive inquiry

The aim of this exhaustive descriptive epidemiological study was to determine the clinical approach to be adopted by practitioners specializing exclusively in pediatric odontology and by orthodontists when confronted with decayed molars in children and adolescents.

MATERIAL AND METHOD

A questionnaire was sent out to all corresponding practitioners (n=2076). Six questions related to treatment decisions taken when faced with decayed permanent first molars (unfavorable short or middle-term prognosis) in patients needing, or not, orthodontic care. The Chi(2) test was used to compare responses.

RESULTS

Thirty-eight per cent of pedodontists (n=38) and 12.5% (n=246) of orthodontists answered the questionnaire. Faced with a permanent first molar with an unfavorable middle-term prognosis, 75.7% needed criteria to help them reach their treatment decision. In decreasing order of importance, these criteria were: presence of the third molar, patient motivation, inter-arch relationship, patient's oral hygiene, facial type, anterior jaw-teeth discrepancy and the number of molars to be extracted. Faced with a permanent first molar requiring extraction and when orthodontic treatment was not required, 31.7% of practitioners decided to close the maxillary space immediately as opposed to 13.4% who closed the space at the mandible. In the presence of a single decayed first molar, 68.7% of practitioners did not extract the antagonist or contralateral first molars.

CONCLUSION

These treatment decisions were not always unanimous and call for a combined approach between dental surgeon and orthodontist.

Prognostic factors for autotransplantation of teeth with complete root formation

OBJECTIVES

The aim of the present study was to evaluate the factors affecting the prognosis of the autotransplantation of teeth with complete root formation.

STUDY DESIGN

A total of 259 transplanted teeth were studied. The significance of each of the prognostic factors was examined in 2 ways, first in a univariate analysis and then in a multivariate analysis. The comprehensive risk combining these factors that remained after multivariate analysis was calculated.

RESULTS

Among 259 transplanted teeth, 27 (10.4%) were judged as unsuccessful cases. In the multivariate analysis, history of root canal treatment of donor tooth, multirooted, maxillary tooth as a donor, and duration of tooth absence at recipient site remained significantly associated with unsuccessful transplantation. Multifarious combination of the significant prognostic factors can decrease the comprehensive risk.

CONCLUSIONS

Minimizing the comprehensive risk by combining significant prognostic factors improved the prognosis of autotransplantation of teeth with complete root formation.

Risk factors affecting third molar autotransplantation in males: a retrospective survey in dental clinics

The aim of this study was to investigate the risk factors affecting long-term prognosis of autotransplantation of third molars with complete root formation in males at dental clinics. Participating dentists were requested to provide information on transplantations they had undertaken from 1 January 1990 to 31 December 2010. Data on a total of 708 teeth from 637 patients were collected. After data screening and elimination, participants of this study consisted of 183 teeth of 171 males ranging from 20 to 72 years of age (mean age, 44·8 years). The cumulative survival rate was 86·0% at the 5-year mark, 59·1% at 10 years and 28·0% at 15 years. The mean survival time was 134·5 months, as calculated by the Kaplan-Meier method. Single factor analysis using the log-rank test showed that the following factors had significant influence (P < 0·05) on survival of transplanted teeth: periodontal disease as the reason for recipient site tooth extraction, fewer than 25 present teeth and Eichner index Groups B1 to C. Cox regression analysis examined five factors: age, smoking habit, recipient site extraction caused by periodontal disease, fewer than 25 present teeth and Eichner index. This analysis showed that two of these factors were significant: fewer than 25 present teeth was 2·63 (95% CI, 1·03-6·69) and recipient site extraction caused by periodontal disease was 3·80 (95% CI, 1·61-9·01). The results of this study suggest that long-term survival of transplanted teeth in males is influenced not only by oral bacterium but also by occlusal status.