Analysis Of Cone-beam CT Imaging Features Of Common Odontogenic Cystic Lesions Of Jaw

Objective: Oral maxillofacial bone is prone to cysts and tumors,which are mostly related to odontogenic tissues.These odontogenic tissues produce two types of benign entities: odontogenic cyst and odontogenic tumor.The most common odontogenic cysts are periapical cysts,dentigerous cysts and odontogenic keratocysts.Ameloblastoma is the most common odontogenic tumor.Since dentigerous cysts,odontogenic keratocysts and ameloblastoma are very similar in clinical manifestation and imaging,the differential diagnosis is more difficult.Besides,the treatment options are different due to the different biological behaviors of the three.Therefore,the accurate preoperative diagnosis is more important.As an effective means of preoperative auxiliary diagnosis,imaging examinations are particularly important to identify different diseases by imaging features.Among them,cone-beam CT,as a new imaging method in the department of stomatology,has been well used in the examination of benign jaw lesions.In recent years,some scholars have reflected the degree of expansion of lesions by quantitative indicators,namely the degree of expansion and the ratio of expansion,and tried to take it as the differential factor between the above diseases.In view of this,this paper,after obtaining the images of the above three diseases by cone beam CT,conducted a retrospective study on the disease by combining the expansion degree and expansion ratio with other relevant differential factors,and analyzed the correlation between these factors and the disease,in order to find the image differential method.Methods: 117 patients with ameloblastoma,dentigerous cyst and odontogenic keratocyst were included in the study.The clinical characteristics(age,sex,jaw position)and imaging characteristics(site,size,shape,internal structure,bone wall continuity,condition of affected teeth and degree of expansion and expansion ratio)of the above patients were retrospectively analyzed.At the axial level with the most prominent lesion expansion,the buccal tongue diameter on the side of the lesion/the same buccal tongue diameter on the opposite side were defined as the degree of expansion.The part of the lesion beyond the normal buccal margin of the lip of the jaw was defined as the swelling area.The normal jaw margin of the affected side was recorded according to the morphology of the corresponding part of the healthy side and the length of the curve was measured.The maximum vertical width of the buccal palate was measured in the swelling area perpendicular to the above curve.At the same time,the manifestations of other related factors in different diseases were observed on the image.SPSS 23.0 was used to analyze and process the data obtained in this study.Results: Among the 118 lesions in 117 patients,there were 39 ameloblastomas,22 odontogenic keratocysts and 57 odontogenic keratocysts.After statistical analysis of the clinical and imaging data of the above lesions,it is find that there were significant differences among three diseases in the maxillary position of the lesion,maximum length diameter,root morphology of affected teeth,the part of the upper jaw,and the shape,internal structure,cortical plate continuity,degree of expansion and buccal expansion ratio in the underjaw(P>0.05).While there was no significant difference between the three diseases in age,gender,the angle and type of impacted teeth in the lumen,maxillary shape,internal structure,cortical plate continuity,expansion degree and expansion ratio,the swelling ratio of the part of the jaw and the lingual side(P>0.05).Conclusion: 1.Conical beam CT can be used in the observation of benign lesions in the jaw with its advantages of high spatial resolution,fast imaging and low radiation.2.Which can be used as the differential diagnosis factors among the three diseases are the lesions in clinical and imaging features of ameloblastoma,odontogenic cyst and odontogenic keratocyst,maximum length diameter,root morphology of affected teeth,the part of the upper jaw,and the shape,internal structure,cortical bone plate continuity,degree of expansion and buccal expansion ratio in the lower jaw.While which cannot be used as the identification standard,and should be considered comprehensively in combination with other related factors are age,gender,the angle and type of impacted teeth in the lumen,maxillary shape,internal structure,cortical plate continuity,expansion degree and expansion ratio,the expansion ratio of the part and the lingual side in the lower jaw.3.Ameloblastoma is not only much larger than odontogenic keratocyst in terms of expansion degree and buccal expansion ratio,but similar in lingual expansion ratio,which again proves the biological characteristics that odontogenic keratocyst grows mainly along the proximal and distal maxilla while ameloblastoma in jaw buccal to grand is more significant.