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

Validation of a Cox prognostic model for tooth autotransplantation

OBJECTIVES

This study aimed to validate our Cox proportional hazards prognostic model for autotransplantation of teeth with complete root formation using prognostic index (PI) and determine whether the prognosis can be predicted.

PATIENTS AND METHODS

The Protocol group, as a training data set for validation, consisted of 259 autotransplanted teeth to create a PI using the Cox model, as described previously. The Pre-protocol group, as the first validation data set, consisted of 95 autotransplanted teeth treated without a protocol. The Post-protocol group, as the second validation data set, consisted of 61 autotransplanted teeth obtained after the establishment of the prognostic model. Because four prognostic factors, including history of root canal treatment (yes), number of roots (multirooted), source of donor tooth (maxillary tooth), and duration of edentulism (≥2.5 months), were selected as a Cox prognostic model, 16 patterns of PI were constructed. First, the autotransplantated teeth in the Protocol group were divided into low- and high-risk groups respectively according to the median of PI as the cutoff value. The survival curves of low- and high-risk groups were calculated using the Kaplan-Meier method and tested using the log-rank test. Then, in the Pre- and Post-protocol groups, all transplanted teeth were divided into low-and high-risk teeth by the median of PI and the survival curves of low- and high- risk teeth were analyzed statistically in a similar manner.

RESULTS

The survival curves of the low- and high-risk groups diverged significantly in the Protocol and Post-protocol groups. In the Pre-protocol group, the curves of the low- and high-risk groups were separated, and the low-risk survival rate was improved.

CONCLUSIONS

Our Cox prognostic model for autotransplantation of teeth with complete root formation was useful in predicting the prognosis by external validation using PI.

A Prospective Study on Autotransplantation of Mandibular Third Molars With Complete Root Formation

Study Design

Autotransplantation, if possible, is a viable option for replacing a missing tooth when a donor tooth is available. The most typical tooth transplant is the transfer of a third molar to a first molar site. No immune reaction results from transplants of this nature. It restores the proprioceptive function and normal periodontal healing; thus, the patient can have a natural chewing feeling and natural biological response.

Objective

This study aims to evaluate the prognosis of autotransplanted mandibular third molar and also to evaluate the cost effectiveness of the treatment performed when compared to the other treatment modalities for prosthetic rehabilitation.

Methods

A prospective study was done in the Department of Oral & Maxillofacial Surgery, Sardar Patel Post Graduate Institute of Dental & Medical Sciences, Lucknow, UP, India, with over 20 patients to evaluate the prognosis of autotransplanted mandibular third molars with complete root formation after atraumatic extraction of first or second mandibular molar, which were randomly selected irrespective of race, sex, caste, and socio-economic status. Regular clinical and radiographical examinations were performed over a period of 1 year and the patients were assessed for pain, swelling, infection, dry socket, periodontal pocket depth, ankylosis, root resorption, tooth mobility, and level of buccal bone in relation to cementoenamel junction (CEJ).

Results

Eighteen out of 20 transplants were successful; only 2 mandibular transplants were extracted because of abnormal horizontal and axial mobility and the reason of failure was attributed to fact that the roots of transplant were short and conical and there was lack of alveolar bone height at the recipient site in one patient, while root resorption was the reason for failure of transplant in the other patient.

Conclusions

This study assessed the efficacy of autotransplantation of molars and the viability of the procedure to replace unrestorable molar teeth; it also supports the hypothesis that transplantation of a mandibular third molar for replacement of a lost or seriously damaged molar tooth could be a reasonable alternative.

Long-Term Survival Rate of Autogenous Tooth Transplantation: Up to 162 Months

Background and Objectives: The purpose of this study is to observe the usefulness of autogenous tooth transplantation by examining the cumulative survival rate according to the period of auto-transplanted teeth as pre-implant treatment. Materials and Methods: This study was conducted on 111 patients who visited Kyungpook National University Dental Hospital and underwent autogenous tooth transplantation between November 2008 and January 2021 (about 13 years). The cumulative survival rate of autogenous tooth transplantation according to the causes of extraction of the recipient tooth (caries, periapical lesion, crack, crown fracture, periodontitis) and condition of opposing teeth (natural teeth vs. fixed prosthesis). The cumulative survival rate of autogenous tooth transplantation according to the age (under 30 vs. over 30) was also investigated and it was examined whether there were any differences in each factor. Results: The average follow-up period was 12 months, followed by a maximum of 162 months. The 24-month cumulative survival rate of all auto-transplanted teeth was 91.7%, 83.1% at 60 months and the 162-month cumulative survival rate was 30.1%. There were no statistical differences between the causes of extraction of the recipient's teeth, differences in the condition of the opposing teeth, and differences under and over the age of 30. Conclusions: The survival rate of autogenous tooth transplantation appears to be influenced by the conditions of the donor tooth rather than the conditions of the recipient tooth. Although autogenous tooth transplantation cannot completely replace implant treatment, it is meaningful in that it can slightly delay or at least earn the time until implant placement is possible.

Effect of Root Canal Therapy on the Success Rate of Teeth with Complete Roots in Autogenous Tooth Transplantation

BACKGROUND

Autogenous tooth transplantation is a reliable method for repairing missing teeth. Although it recently became a recognized and feasible treatment method in dentistry, the long-term efficacy of root canal therapy (RCT) has not been well confirmed. This study is aimed at determining whether RCT has a good effect on the success rate of teeth with complete roots in autogenous tooth transplantation.

MATERIALS AND METHODS

Data were collected from the Korea University Guro Hospital. Data of patients who underwent autogenous tooth transplantation within 9 years were collected. We selected 29 teeth with complete roots as the research subjects in our study. None of the patients had any systemic diseases. All cases in this study were obtained with patient permission.

RESULTS

According to the tooth vitality test, the autogenous teeth tested negative in dental pulp test and function. Nine of the 29 teeth with autogenous tooth transplantation were treated with RCT and survived throughout the observation period. However, 20 autogenous teeth were not treated with RCT, and eight of them did not survive. All statistical analyses were performed using IBM SPSS 20.0. The null hypothesis was rejected (p < 0.05).

CONCLUSION

For complete root teeth, the success rate after autogenous tooth transplantation after RCT is higher than that of teeth not treated with RCT.

Third molar autotransplant planning with a tooth replica. A year of follow-up case report

The advantages of dental autotransplantation and its high level of clinical success mean that it should be considered as a therapeutic option when replacing a lost tooth. In order to achieve optimum results, it is necessary to know the technique of dental autotransplantation, promoting its use whenever the clinical conditions to perform it are present. The objective of this article is to describe the technique in detail by means of a clinical case of a dental autotransplant whose donor tooth was a third unerupted molar. A 39-year-old male patient with no medical history of interest. On clinical examination, tooth 2.6 shows vertical fracture with indication of exodontia. A compatibility study is carried out using a CBCT and after this, a subsequent preparation of a 3D-printed replica of the donor tooth 2.8 is made. A step-by-step description is given of the autotransplantation technique from 2.8 to 2.6. After this, antibiotic coverage, semi-rigid splinting and root canal treatment are carried out in a short time. Results are shown at 12 months. The main factor for the success of this technique is the preservation of periodontal ligament cells. The unerupted teeth are the only ones that fully preserve the periodontal ligament, but they require greater surgical skills. Autotransplantation is a predictable treatment alternative to dental implants, being above all an option indicated to replace teeth with dental fissures or vertical root fractures or poor restorative and/or endodontic prognosis. The third molars are the most used teeth for transplantation, due to their indications for extraction in a high percentage preserving the entire periodontal ligament. The diagnosis by CBCT and the use of 3D- printed replicas of the tooth to be transplanted have meant a highly significant improvement in the prognosis and predictability of the technique. Key words:Dental autotransplant, tooth replica, third molar.

Autotransplantation of mature impacted tooth to a fresh molar socket using a 3D replica and guided bone regeneration: two years retrospective case series

Background

The aim of this study was to evaluate the clinical outcome of autotransplantation of mature third molars to fresh molar extraction sockets using 3D replicas.

Methods

Ten patients underwent teeth autotransplantation with or without GBR. We observed the mobility, percussion, radiography examination, the probing depth and the masticatory function of the transplanted teeth during 2 years following up, which were transplanted into fresh molar sockets by using 3D replicas, and GBR when it is necessary.

Results

The average extra-oral time of donor tooth had been shortened to 1.65 min when used the 3D replica. Some probing depth of the transplanted tooth were deeper than 3 mm at 4 or 5 weeks temporarily. And one patient felt slight sensitive when chewing with soft food at 4 weeks, then disappeared. The clinical examination of the autotransplantation teeth during 1 year follow-up showed no sign of failure.

Conclusions

The tooth autotransplantation using 3D replica with or without GBR is an effective method which can reduce the extra-oral time of the donor teeth and may result in less failure.

Autotransplantation of third molars with completely formed roots into surgically created sockets and fresh extraction sockets: a 10-year comparative study

The aim of this study was to analyze and compare the long-term clinical outcomes of mature third molar autotransplantation in surgically created sockets and fresh extraction sockets with regard to survival and functional success rates. A total of 65 third molars with completely formed roots were autotransplanted in 60 patients (average age 33.1 years). Thirty-six of the teeth were autotransplanted into surgically created sockets with or without guided bone regeneration (GBR; delayed autotransplantation), while 29 were autotransplanted into fresh extraction sockets (immediate autotransplantation; control group). All patients underwent annual clinical and radiographic examinations (average follow-up 9.9 years, range 7-13 years). The survival rates for the control, GBR, and no GBR groups were 93.1%, 95.2%, and 80.0%, respectively, with no significant differences among the groups. There were no statistically significant differences among the groups with regard to the frequency of inflammatory root resorption or root ankylosis. Age did not influence the clinical outcomes. These results suggest that the autotransplantation of third molars with completely formed roots is effective in both surgically created and fresh extraction sockets and provides a high long-term success rate if cases are selected and treated appropriately.

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.

Procedures for treating spaces vacated by loss of transplanted teeth

The main reasons for loss of autotransplanted teeth are different from those involved in natural teeth loss. The aim of this study was to investigate which procedures were employed to treat spaces vacated when autotransplanted teeth were lost. Participating dentists were requested to provide information on transplantations they had undertaken. A total of 614 teeth in 552 patients (37 dentists) ranging in age from 17 to 79 years (mean age: 44.1 years) were examined. A total of 102 transplanted teeth were lost during the observation period. Procedures for treatment of spaces vacated were not influenced by main reason for transplanted tooth loss. The procedure used to treat depended on the original prosthodontic treatment of the transplanted teeth. For single crowns, the spaces were left empty (33.9%) or replaced by bridge work (30.5%), implants (20.3%), or dentures (10.2%). For single crowns in the upper and lower second molar regions, the spaces were usually left empty (upper 100%, lower 71.4%), while for those in the upper and lower first molar regions, the spaces were often replaced by bridge work (upper 41.7%, lower 50.0%). For bridge abutments, spaces were replaced by dentures (42.9%), implants (33.3%), or left empty (14.3%), and in the lower second molar region, they were mostly replaced by implants (5 cases, 41.7%). For most denture abutment cases, the spaces were replaced by dentures (88.9%). During the survival period of the transplanted teeth, the masticatory burden on the other teeth is reduced and the adjacent teeth are supported by the transplanted tooth. Even if transplanted teeth are eventually lost, traditional procedures can be performed to fill the vacated space.

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.