Anatomy Research Of The Mesio-buccal Canal System Of Permanent Maxillary First Molars

Objective:To investigate the root canal configuration of extracted permanent maxillary first molars and the frequency of a mesio-buccal root with two canals in patients.Methods:80 extracted human maxillary first molars were examined.After routine endodontic access to cavity,the following observations were made:(1)The root canals were detected and prepared under the stereomicroscope.(2)The number and configuration of the apical foramen were observed with naked eyes.(3)The working length and the distance from the apical foramen to the tip of the root were measured with the vernier caliper.(4)After crown removal,the root canal orifices were located.(5)The vernier caliper was used to measure the distance between the root canal orifices.(6)Roots were prepared using a clearing technique to demonstrate the canal system.In the endodontic clinic,root canal therapy was carried out in 52 maxillary first molars.The MB and MB₂ canals in the mesiobuccal root were located by two experienced dentists with an endodontic explorer and prepared with K-files and 15%EDTA.The number of root canals was recorded.Results:In the mesiobuccal root of the extracted maxillary first molar,1.71 extracted human maxillary first molars had two canals with the help of stereomicroscope.(an overall incidence of 88.75%) 2.The average working length of MB,MB₂,DB and P were 18.34mm,18.02mm,18.10mm,20.21mm.The number of the apical foramen of MB,DB and P were 121,81,80.3.The average distances from the apical foramen to the tip of MB,DB and P were 0.68mm,0.30mm,0.53mm with the maximum of 2.5mm,2.0mm,2.5mm.4.The average distance between the orifices of MB₁ and MB₂ was 1.75mm.5.Of 80 extracted human maxillary first molars,74(an overall incidence of 92.50%)had two canals,71 were Typeâ…¡andâ…¢canal configuration6.Of the 52 patients,MB₂ was located in 69.23%of the maxillary first molars with naked eyes.Conclusion:MB₂ canals in maxillary first molars could be detected with high incidence.Therefore,we should pay attention to locate MB₂ to improve the long-term effect of root canal therapy.