CBCT Study Of Root And Canal Morphology Of Mandibular Second Molars In Western Guangxi

Objective:In this study,cone beam computed(CBCT)was used to observe the root and root canal morphology of mandibular second molars in Western Guangxi,so that clinicians can better understand the morphological characteristics of mandibular second molars in this area,and provide reference for clinical diagnosis and treatment,so as to better guide clinical practice.Methods:A collection of 564 patients(305 males and 259 females)who attended the Department of Stomatology,the Affiliated Hospital of Youjiang National Medical College,Baise City,Guangxi Zhuang Autonomous Region from January 2018 to January 2020.The imaging data obtained from CBCT scans due to the need for treatment were selected as the experimental research objects without tooth developmental diseases,carious diseases and1128 untreated mandibular second molars.The Planmeca Romexis CBCT machine(PLANMECA,Finland))And its own image analysis software to observe the root and root canal morphology of the experimental subjects,mandibular second molars,count and analyze the differences between the root and root canal morphology and gender,age and ethnicity,and bilateral root and root canal symmetry Circumstances,the collected data will be used for statistical analysis using R language 3.6.1 software.Results:Among the 1128 second permanent mandibular molars,4 of the three-rooted type,accounting for 0.35%;834 of the double-rooted type,accounting for 73.94%;14 of the conical fusion root type,accounting for 1.24%;276 of the C-shaped root type,accounting for24.47 %,no other root types were found.The detection rate of double-rooted and triple-rooted males was higher than that of females(P<0.05),while the detection rates of C-shaped and tapered roots were both higher for females than males(P < 0.05);double-rooted And the detection rate of C-shaped root type is low age group>middle age group>high age group(P<0.01);the root type of Zhuang people is mainly double root type,followed by C-shaped root type(P<0.01).Among the double-rooted mandibular second molars,the mesial root canal type IV accounted for the highest proportion of 46.04%,and the distal root type I accounted for the highest proportion of 95.32%.There was a statistically significant difference in the composition ratio of mesial root canal types between men and women(P < 0.05).Among them,the mesial root canal types of men and women were mainly type IV,followed by type I(P<0.01),the detection rate of mesial root type IV is more male than female(P<0.05),and the difference in composition ratio of mesial root canal type between Zhuang and Han nationalities is statistically significant(P<0.05),except for type II,The detection rates of types I,III,IV,and V were higher in Zhuang nationality than in Han nationality(P<0.01).The mesial root canal classification of Zhuang population was mainly type IV,followed by type I(P<0.01).The mesial root canal types of the low,middle and high age groups are mainly type IV(P < 0.01),and the incidence of mesial root type IV is low-age group>middle-age group>high-age group(P<0.01)).The C-shaped root canal is more continuous at the mouth of the root canal,and the more downward,the worse the continuity.In three different levels of root canal opening,root middle and root apex,the root canal opening is mainly C1 type,the middle root is mainly C3 type,followed by C2 type,and the root apex is mainly C3 type(P<0.01).The bilateral root symmetry rate was 44.77%,and the bilateral root canal symmetry rate was 36.35%.Among them,the bilateral symmetry of the root canal is higher in males than in females(P<0.05),and the symmetry of root canals in males is significantly higher than that in females(P < 0.01),and the symmetry of roots and root canals of Zhuang people is significantly higher than that of Han and other ethnic groups(P<0.01).Conclusions:Although the root and root canal morphology of the mandibular second molars of the people in western Guangxi are complex and diverse,there are also certain rules:1.The root morphology of Zhuang people in western Guangxi is mainly double-rooted;males are mainly double-rooted,and females are mainly C-shaped roots;the distribution of double-rooted types in different age groups is inconsistent,18-35 years old The incidence of double root type in the population is higher than that of other age groups.2.The mesial root canal morphology of the double-rooted mandibular second molars of the Zhuang people in western Guangxi is mainly type IV;the detection rate of type IV is higher in males than females;the distribution of type IV is inconsistent in different age groups,18-35 years old The incidence of type IV in the age group is higher than that of other age groups;the morphology of the distal root canal is mainly type I.3.The root canal morphology of the C-shaped root mandibular second molars of the Zhuang nationality in western Guangxi is mainly type C1 at the root canal opening,and type C3 at the middle and apical parts of the root canal;the root canal is 1/3 more continuous High,the more to the apex,the worse the continuity of the C-shaped root canal.4.The bilateral root and root canal symmetry rate of the mandibular second molars of the Zhuang people in western Guangxi is higher;men are higher than women;the distribution is inconsistent in different age groups,and the bilateral symmetry rate in the 18-35 years old age group is higher than other age groups.