| Objective Supernumerary teeth are a common developmental abnormality of the number of teeth,which mostly occur in the anterior maxillary area.Therefore,the extraction of supernumerary teeth is one of the routine operations of oral and maxillofacial surgery.In this study,CBCT was used to collect and analyze the clinical data of patients and the characteristics of supernumerary teeth,including the number,shape,position,direction,root morphology,and complications related to supernumerary teeth,such as the delayed eruption or displacement of adjacent teeth,the formation of cysts,the absorption of adjacent roots,the development of adjacent permanent teeth with supernumerary teeth.The aim of this study was to examine the radiographic features associated with complications related to supernumerary teeth,to determine the relationship between their characteristics and their effects on permanent incisors,and to evaluate the potential risk of supernumerary teeth.So we can provide a reference basis for clinicians in considering the timing of treatment and formulating personalized diagnosis and treatment plans in order to reduce the occurrence of intraoperative and postoperative complications as well as improve the level of diagnosis and treatment.Method This study is a retrospective study.All patients with the diagnosis of supernumerary teeth by periapical and panoramic radiographs attended Tianjin Medical University Stomatology Hospital for examination using CBCT between January 2017 to April 2020.The study sample comprised 120 patients was made from.A total of 120 patients and 176 supernumerary teeth were selected to meet the inclusion criteria of CBCT data.All clinical and CBCT imaging data were collected from patients’ records in the computer database of the CBCT machine.The characteristics of the patients,the accurate location and evaluation of supernumerary teeth and adjacent teeth were recorded according to classification.The final variables selected for inclusion in the study mainly include the following three categories: the patient’s demographic characteristics(gender,age),the information characteristics of extra teeth(number,morphology,location,direction)and related complications(local malformation such as torsion,displacement,delayed germination,cyst formation,absorption of adjacent tooth roots,and other developmental abnormalities).The related variables of complications and the other two kinds of variables were statistically analyzed by statistical software,and the rules of supernumerary teeth damage to adjacent teeth and complications were summarized,so as to determine the best treatment timing and reduce occurrence of complications related to supernumerary teeth.All CBCT data are measured by the same investigator.Result 1.General condition of patients.In this study,120 patients with multiple teeth were included,92(76.7%)males and 28(23.3%)females.The ratio of males to females was 3.28:1.The average age of the patients was 10.29 ± 7.89 years old,and the age range was 5-68 years old.2.General situation of supernumerary teeth.A total of 176 supernumerary teeth were included in this study,including 140 males and 36 females,with an average of 1.47 per person.The number of supernumerary teeth was 67(55.8%)in 1 case,51(42.5%)in 2 cases,1(0.8%)in 3 cases,and 1(0.8%)in 4 cases.Among them,25 erupted and 151 were impacted.According to morphological classification,they were divided into conical 127(72.2%),tuberculate 33(18.7%),supplemental 12(6.8%)and odontoma 4(2.3%).According to the growth direction,they were inverted in 84 cases(47.7%),orthopedic position in 40 cases(22.7%),transverse(lip and palate direction)in 29 cases(16.5%),transverse(proximal and distal)in 19 cases(10.8%),and unoriented in 4 cases(2.3%).3.Classification of supernumerary teeth in three-dimensional position.Supernumerary teeth can be divided into six categories according to the relationship between supernumerary teeth and dental arch and adjacent teeth in sagittal plane.Class A: 70(39.8%)cases of low palatal position,class B: 46(26.1%)cases of middle palatal position,class C: 7(4.0%)cases of high palatal position,class D: 42(23.9%)cases of low arch position,class E: 9(5.1%)cases of high arch position,and class F: 2(1.1%)cases of high lip position.4.Developmental stages of supernumerary teeth.According to the relationship between the location of the coronal plane and the central and lateral incisors,it can be divided into three areas: area I: 127(72.2%)between the central incisors;area II: 42(23.9%)between the central and lateral incisors;Area III: 7(4.0%)between the lateral incisors.4.Stages of the development of supernumerary teeth.The developmental stages of supernumerary teeth were mainly concentrated in stage 10,and the number of cases in stages 6-10 were 5(2.8%),6(3.4%),14(8.0%),23(13.1%)and 124(70.5%),respectively.5.Complications related to supernumerary teeth.A total of 26 patients with malocclusion deformity occurred,accounting for 21.7% of the total number of study cases,88 teeth at the tooth level,29 cases of adjacent tooth displacement,accounting for 16.5%,16 central incisor diastema,adjacent tooth torsion and reversal,accounting for 9.1%.Delayed eruption or impacted 11,accounting for 6.3%,12 cases of cyst or cyst tendency,accounting for 6.8% of the total teeth.No absorption of adjacent teeth was found.6.The relationship between the position of supernumerary teeth and nasopalatine canal and nasal floor.The types of supernumerary teeth without contact were 68(38.7%),intimate were 56(31.8%)and protruding with nasopalatine canal were 52(29.5%),and 152(86.4%),16(9.1%),8(4.5%),respectively.7.Statistical analysis results.The distribution of the number of supernumerary teeth is different between different genders,and the difference is statistically significant.But there is no statistical difference in the distribution of supernumerary teeth in different age groups and dentition status.The developmental stages of supernumerary teeth are different in different dentition,and the developmental stage of supernumerary teeth is higher than that of adjacent teeth,suggesting that the development of supernumerary teeth is earlier than that of adjacent teeth.There was no statistical difference in the classification of supernumerary teeth in coronal plane and sagittal plane and among different forms of supernumerary teeth.There was no significant difference in developmental stages between adjacent teeth and contralateral homonymous teeth,suggesting that supernumerary teeth had no effect on the developmental stages of adjacent teeth.There was no statistical difference of the occurrence of malocclusion in different position,direction and shape.In the analysis of the relationship between the supernumerary teeth and the adjacent bone structure,it is found that the midline area(area II)and the lateral incisor and canine(Area III)are more likely to be far away from the nasopalatine canal,and the possibility of close relationship is less,while the midline area I is the opposite,which is consistent with our intuitive understanding.In sagittal classification,it is more likely that the low palatal position(Class A)protrudes into the nasopalatine canal,while the middle low position(Class D)in the dental arch is opposite,which is more likely to be far away from the nasopalatine canal.In the middle palatal position(class B)and the high position in the dental arch(class E),it is most likely to penetrate the bone plate of the nasal floor,that is,it is more closely related to the nasal floor.Conclusion 1.The prevalence rate of supernumerary teeth among different gender is different,males are susceptible,and the distribution of the number is different between different genders.2.The supernumerary teeth complete the development earlier than the adjacent teeth,and the development of the adjacent teeth is not affected by the supernumerary teeth.3.Cysts from supernumerary teeth and other complications related to supernumerary teeth have no correlation with their location.4.Supernumerary teeth that are closely related to the surrounding tissue structure should be examined in detail to guide the surgical path. |
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