[Screening and analysis of prognostic factors of repairing single missing tooth by autotransplantation of teeth].

Objective: To screen and analyze the factors affecting the prognosis of replacing single missing tooth by autograft tooth, so as to provide reference for clinical judgment of surgical prognosis. Methods: A total of 176 patients (188 teeth) underwent autotransplantation of teeth in the Department of Oral & Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University from January 2017 to December 2019, including 85 teeth of males and 103 teeth of females were involved. The age was (33.0±9.8) years (16-65 years). The possible factors affecting the prognosis of replacing single missing tooth by autograft tooth were summarized and grouped, and the clinical and imaging data were recorded and judged. The surgical records and photographic data from the patients' previous medical records were retrospectively analyzed. The survival analysis method was used for statistical analysis to screen out the factors affecting the cumulative survival rate of transplanted teeth. Results: The 5-year cumulative survival rate of 188 transplanted teeth was 88.4%. Univariate Log-Rank analysis showed that age (P<0.001), sex (P=0.008), smoking (P<0.001), position of recipient area (P<0.001), height of alveolar bone in recipient area (P<0.001), time of donor tooth in vitro (P<0.001), use of donor model (P<0.001) and initial stability (P<0.001) were significantly correlated with cumulative survival rate of transplanted teeth. Multivariate Cox proportional hazard regression analysis showed that smoking (ß=-2.812, P=0.049), alveolar bone height (ß=1.521, P=0.020), donor time (ß=-2.001, P=0.019), use of donor model (ß=1.666, P=0.034) and initial stability (ß=-1.417, P=0.033) were significantly correlated with the cumulative survival rate of transplanted teeth. Conclusions: The prognosis of autogenous tooth transplantation can be predicted by smoking, height of alveolar bone in recipient area, time of donor teeth in vitro, use of donor model and initial stability. Good prognosis of transplanted teeth can be obtained by using donor model during operation, reducing the time of donor teeth in vitro, taking effective methods to restore alveolar bone height, maintaining good initial stability, and good oral health education after operation.

[Clinical observation of three-dimensional printing donor tooth model in peri-operative period of autotransplantation of tooth].

Objective: To prepare a three-dimensional (3D) printing donor tooth model and to observe its application in the peri-operative period. Methods: In part one, 192 cases (2017.9-2019.8) from Department of Oral & Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University ï¼»107 males and 85 females, age (34.2±10.7) yearsï¼½ which need autotransplantation of teeth (ATT) were collected. Whether the donor teeth can be completely extracted was predicted through clinical and imaging examination (first prediction). The second prediction was supplemented by the three-dimensional printing model of the donor teeth. Each of the prediction was compared with the actual results and the coincidence rate was calculated. In part two, 64 cases (2017.9-2019.8) from Department of Oral & Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University ï¼»28 males, 36 females, age (30.2±8.3) yearsï¼½ which need ATT were randomly divided into the model group and the donor group. The time of alveolar fossa preparation, time of donor tooth in vitro, times of trial implantation and time of pulptomy and root canal location were recorded respectively. Results: In part one, the coincidence rate between the second prediction and the actual results ï¼»97.4%(187/192)ï¼½ was significantly higher than that of the first prediction ï¼»93.2%(179/192)ï¼½ (P<0.05). In part two, the preparation time of the alveolar fossa in the maxillary and mandibular were (18.8±4.6) and (22.7±3.4) min, the time of the teeth in vitro were (3.0±0.6) and (2.1±0.6) min, the times of trial implantation were (1.3±0.8) and (1.0±0.9), and the time of pulpotomy and root canal location were (4.3±0.6) and (4.0±0.5) min. All values in the model groups were better than those in the donor group (P<0.05). Conclusions: The 3D printing model is accurate. It can be used in autogenous tooth transplantation to shorten the preparation time of alveolar fossa and time of donor tooth in vitro, and reduce the times of trial implantation of donor teeth, and to help to improve the prediction accuracy of complete extraction of donor teeth and the time of pulpotomy and root canal location.