The influence of aging changes on the root canal system of the mandibular second premolar teeth

WANG Lishuhan; GUO Xiao-long; ZHANG Feng-cheng; LI Hong-bo

doi:10.3969/j.issn.1672-2973.2018.02.003

Abstract：Objective:Observing the age-related changes of root canal system of mandibular second premolars by using cone beam CT (CBCT),so as to provide some references for clinical treatment.Methods:According to inclusion and exclusion criteria,a total of 328 mandibular second premolars were selected from the Department of Stomatology of PLA General Hospital in November 2015-2017 November.They were divided into 6 groups in the light of their age:21-30,31-40,41-50,51-60,61-70 years old,＞ 70 years old,and obtain the CBCT images of the six groups.Observe and statistics the following indicators:root canal type proportion (Vertucci theory),and connection angle of buccal pulp horns and buccal&lingual enamel junction (ECJ).The six groups were compared with the chi square test,and the GraphPad Prism was used to analyze the histogram (average and standard deviation).Results:The results showed that type Ⅰ root canal type was the most common,the proportion is as high as 96.6％ (317/328),which accounts for the highest proportion in all age groups,and the difference was not statistically significant (P＞0.05);and about 3.6％ teeth (11/328) type Ⅴ root canal were found,and there was no significant difference in age group (P＞0.05).The connection angle of BB-BL displayed,before the age of 50,the average angle was about 36.1 degrees,and there is no obvious age-related changes,but the angle reduced to 28.9 degrees after 50 years of age,while the angle is significantly smaller for 23.9 degrees after the age of 70,and the difference wasstatistically significant (P＜0.05).Conclusion:The application of CBCT makes the study of the root canal system becomesimple and accurate,the age has no effects on the root canal type,but the calcification of root canal because of aging factorswill make the root medullary cavity narrow,BB-BL angle decreased,which increases the complexity of root canal system.