A Study On The Surgical Access And Surgical Injury To The Adjacent Permanent Teeth Related To The Removal Of Mesiodens

Objective: Supernumerary teeth is a common disease of abnormal tooth number,of which the most prevalent is mesiodens.Current studies on surgical access to multiple teeth are scarce.In this paper,we develop a new classification of mesiodens with respect to surgical access and evaluate it.It also explores the effects of apical exposure,grinding of roots,and root amputation on the pulp vitality of maxillary anterior teeth in New Zealand rabbits,using iatrogenic injury to adjacent teeth during surgery as an entry point.Methods:1.Case data from 533 mesioden patients seen at the Stomatological Hospital of Kunming Medical University from September 2015 to May 2022 were collected for this retrospective study.The classification of mesiodens was developed based on the patients’ surgical approach,operation time,and surgical complications,combined with the clinical experience of our group.From the case data of 533 patients,200 were randomly selected and sent to each of the 3 oral and maxillofacial surgery specialists for surgical approach selection.The rate of compliance between the specialists’ selection and the results of this classification interpretation was analyzed.2.40 New Zealand rabbits were divided into the exposed apical group and the truncated apical group.In the exposed and polished apical group,part of the bone was removed from the maxillary bone corresponding to the apices of the upper incisors until the operator could directly see all the apical foramina,and the distal mesial surface of the roots was polished to a chalky color.Some of the experimental animals were executed at 1 day,1 month,2 months and 3 months after surgery,respectively,and the pathological changes of the pulp tissue were observed under the light microscope after hematoxylin-eosin staining with healthy teeth as controls.Results:1.Four classifications of mesiodens were developed based on the surgical approach,with the labial approach chosen for Class I and III extractions,the palatal approach for Class II procedures,and the intraoral transnasal approach for Class IV.The results of the interpretation of the new classification were compared with the surgical approaches chosen by 3 senior surgeons,and the rates of compliance were 94.83%.2.The root lengths of the exposed polished group and the truncated apical group were statistically significantly different at 1,30,60,and 90 days postoperatively(P < 0.01),whereas the root lengths of the exposed polished group and the control group were not significantly different at all four time points.3.The exposed group showed only one case of pulp congestion at 1 day postoperatively,but the rest showed normal pulp tissue;while all teeth in the truncated group showed different degrees of inflammation and necrosis,among which the 1 day postoperative group showed mild inflammation,the 30 days postoperative group showed one case of mild inflammation and four cases of severe inflammation with minor pulp necrosis,and the 60 days postoperative group showed one case of In the 60-day postoperative group,1 case of severe inflammation with minor pulpal necrosis and 4 cases of extensive pulpal necrosis were observed,and in the 90-day postoperative group,extensive pulpal necrosis was observed in all teeth.Statistically significant differences were found between the exposed and truncated groups at 1 day postoperatively(P < 0.01),30 days postoperatively(P < 0.01),60 days postoperatively(P < 0.01),and 90 days postoperatively(P < 0.01).Conclusions:1.The new classification developed in this study has a high rate of correctness and a short time required for judgment,which can guide young oral and maxillofacial surgeons to ease the selection of surgical access and shorten operative time and avoid surgical side injuries and complications due to incorrect selection of surgical access.2.After exposing the apical foramen and polishing the root surface,the New Zealand rabbit teeth developed at the same rate as normal teeth;however,truncation of the roots caused the teeth to stop developing.3.Debridement of the apical region,exposure of the intact apical foramen,and polishing of the root surface did not necessarily affect the pulp vitality of New Zealand rabbits,and 5% of the pulp tissue in this group of sample teeth in this study showed pulp filling.The truncation and removal of some of the roots allowed all the sample teeth to change from inflammation to necrosis over time.