Objective: The aim of this study is to determine the prevalence of second mesio-buccal canal in permanent maxillary first molars.

Study Design: Cross sectional study.

Place and Duration: Dr Ishrat ul Ebad Khan Institute of Oral Health Sciences, Karachi during the period from February 2020 to January 2021

Patients and Methods: Three hundred and fifty cases of both genders were presented in this study. Patients were aged between 18-60years. Patients’ detailed demographics including age, sex and body mass index were recorded after taking written consent. Local anesthesia was given for isolation of rubber dam. The pulp chamber floor was clearly visualized and the access cavity was ready. The location of the MB2 channel in three phases was done. Complete data was analyzed by SPSS 22.0 version.

Results: Mean age of the patients were 30.14±17.47 years with mean BMI 25.61±8.25 kg/m2. Among 350 cases, Majority of the patients 225 (64.3%) were male while the rest 125 (35.7%) were females. Majority of the patients were from age group 20-30 years and less patients were between 51-60 years old. Frequency of second mesiobuccal canal was found in 280 (80%) patients.

Conclusion: We concluded in this study that prevalence of MB2 channel was reported in 80% in the initially permanent maxillary molars. Most MB2 canal apertures are distal from the main MB channel and most MB2 apertures are palatal.

Key words: Permanent maxillary first molar, MB2 canals, Frequency