| Purpose:The key to the success of autotransplanation of tooth(ATT lies in the active induction of tissue healing and regeneration by periodontal ligament after autograft.However,due to the complexity of ATT and the combination of multidisciplinary application,there are many factors affecting its prognosis.In the first part of this study,through a retrospective study of the cases of ATT,screening and statistical analysis of the relevant factors that may affect the prognosis,it is concluded that it can provide scientific guidance for the operation of ATT.To provide accurate judgment for the prognosis of ATT and improve the level of communication between doctors and patients.With the development of material science and 3D printing technology,more and more3 D printing models are used in the medical field,especially in stomatology,which provide great convenience for clinicians.The second part of this study provides a basis for clinical application by analyzing the three-dimensional accuracy and other performance characteristics of 3D printed tooth models made of photosensitive resin,polylactic acid and cobalt-chromium alloy.Method:PART ONE Screening and analysis of factors affecting the prognosis of missing teeth repaired by ATTBy reviewing the relevant literature at home and abroad on the prognostic factors of ATT,screening out the possible influencing factors,defining the prognostic criteria and drawing up the follow-up examination table after autologous tooth transplantation,determining the follow-up cases and number,completing the face-to-face follow-up and online follow-up,and determining the prognosis.The data of patients during operation were collected,combined with the follow-up results for statistical analysis,the important factors affecting the prognosis of autologous tooth transplantation were analyzed and the relevant model was constructed.Contact patients with ATT from January 1,2017 to January 1,2020 for screening,and then contact face-to-face follow-up by telephone;for inconvenient face-to-face follow-up,online follow-up is proposed.The patients were examined clinically by two surgeons according to the items listed in the diagnostic criteria,including tooth mobility,percussion,periodontal condition,follow-up treatment and imaging examination,and fill in the followup examination form after autologous tooth transplantation.if there are differences,a consensus can be reached through discussion by a third experienced doctor.The peri-operative clinical and imaging data of the patients were collected,and the influencing factors were collected according to the results of previous literature.including(1 the general condition of the patient(sex,age,systemic disease;(2 donor tooth condition(donor tooth position,tooth root morphology,donor tooth health status;(3recipient area(alveolar bone condition,gingival condition.(4 intraoperative operation(in vitro operation time,alveolar fossa preparation,initial stability;(5 fixed time and materials;(6 pulp vitality monitoring or root canal therapy;(7 oral hygiene maintenance of patients.The cumulative survival rate and average survival time of the transplanted teeth were calculated by Kaplan-Meier method,and the survival curve was drawn.In the analysis of related factors,logarithmic rank test was used to analyze the difference of survival curve between the two groups,and the Cox proportional hazard regression model was constructed,and the key factors affecting prognosis were determined according to Cox proportional hazard regression analysis(P<0.05.PART TWO Comparison and analysis of the characteristics of three-dimensional donor tooth models printed by different materials and techniquesA total of 20 cases were selected from January 1,2022 to June 30,2022 in the Department of Oral surgery of the third affiliated Hospital of Air Force military Medical University.The third molars were examined by CBCT before operation.All the teeth were stored in 4% paraformaldehyde solution to prevent deformation,and each sample was marked No.1-20.The CBCT data of 20 patients were collected,the third molar extraction data were extracted by Mimics software,and the third molar data were printed with photosensitive resin,polylactic acid and cobalt-chromium alloy.The dental digital impression instrument was used to scan the No.1-20 third molar to obtain the digital model to collect data,and then the dental digital impression instrument was also used to scan the tooth models of three materials corresponding to the No.1-20 tooth to obtain the digital model.Collect and organize data.The digital models obtained by scanning tooth models of various materials were compared with the corresponding digital models of teeth,and 3D analysis was carried out to obtain the RMS values of different material model teeth and corresponding isolated teeth.SPSS25.0 statistical software was used to process the data,and the data were expressed by(mean ±standard deviation((?) ±s.Single factor analysis of variance(One Way AVONA and multiple comparison LSD method were used.RESULTS:PART ONE Survival analysis curve results: the 1-,2-,3-,4-and 5-year cumulative survival rates of 188 transplanted teeth were 100%,95.7%,90.6%,88.4% and 88.4%,respectively.Univariate analysis showed that age,sex,smoking status,location of recipient area,height of alveolar bone in recipient area,time of donor teeth in vitro,use of donor model and initial stability were significantly correlated with the survival rate of transplanted teeth(P<0.05.The results of multivariate analysis showed that smoking status(0.049,alveolar bone height(0.020,donor time(0.019,use of donor model(0.034 and initial stability(0.033 were significantly correlated with the survival rate of transplanted teeth.Among them,the failure risk of smokers was 16.667 times higher than that of non-smokers,the failure risk of donor teeth in vitro time longer than 15 min was 7.407 times that of donor time≤15min,the failure risk of insufficient alveolar bone in recipient area was 4.579 times that of patients with sufficient alveolar bone height,the failure risk of unused model group was 5.293 times higher than that of model group,and the failure risk of initial stability of grade 2 was 4.132 times of that of grade 1.PART TWO The RMS values of 60 3D printing models made from three kinds of printing materials were registered with the standard model by statistical analysis,the results of single factor analysis of variance showed that P<0.05,there was no statistical difference.Combined with the mean values of the three groups,it shows that there is no significant difference in the accuracy of the three printing materials in the donor tooth model.Polylactic acid has the advantages of fast printing speed,low price,convenient disinfection and biodegradability;photosensitive resin printing technology is mature and the price is medium,but its manufacturing process may produce toxic substances;cobalt-chromium alloy has good mechanical properties and resistance to high temperature and high pressure,but the printing cycle is relatively long and the cost is high.CONCLUSION1、In this study,the prognosis of ATT can be predicted by five factors: smoking,height of alveolar bone in recipient area,in vitro time of donor teeth,use of donor model and initial stability.Use the donor model during the operation,reduce the time of donor teeth in vitro,take effective methods to restore the height of alveolar bone,maintain good initial stability,and do a good job of oral health education after operation.A good prognosis of transplanted teeth can be obtained.2、There is no significant difference in three-dimensional accuracy of models by polylactic acid,photosensitive resin and cobalt-chromium alloy compared in this study,and they all show the characteristics of high precision and convenient storage and measurement,but the printing cost of polylactic acid model teeth is low,easy to disinfect,biodegradable and cost-effective,so it can be used as the first choice of model teeth and is worthy of clinical application. |
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