Date of Award

Spring 1-1-2013

Document Type


Degree Name

Master of Science (MS)



First Advisor

Olsen, Kris

Second Advisor

Gaffney, Joseph

Third Advisor

Hefti, Arthur


Purpose: The primary reason for non-surgical root canal treatment (NSRCT) failure in an upper molar is inadequate cleaning, shaping and filling of the second mesio-buccal root canal (MB2). Failure to locate and treat a present MB2 will lead to a worsened long-term prognosis. This retrospective study investigated the treatment rate of MB2s in a sample of patients who were treated in Marquette University School of Dentistry's (MUSOD) advanced dental education program in Endodontics.

Materials and Methods: The study protocol was approved by Marquette's IRB. Data were gathered from records of 447 patients who received endodontic treatment between 2008 and 2012 and include; presence of an MB2 (dependent variable), tooth number, patient age (years), and gender (independent variables). Personal identifiers subject to HIPAA regulations were not collected. Presence of an MB2 was determined from clinical notes and verified radiographically. Frequencies of present or absent MB2s were tabulated as a function of various independent variables and statistically analyzed using chi-square tests.

Results: Overall, 50.3% of all patients presented with an MB2. Male and female patients had MB2s in 60.6% and 43.8%, respectively. MB2s were found in 53.1% (172 out of 324) and 43.1% (53 out of 123) of maxillary first and second molars, respectively. The mean age of the sample was 42.4 years. Below the mean age, MB2 canals were found in 56.0%, while above the mean age, they were present in 43.2%. There was no statistically significant difference in side distribution (left side of maxillary arch compared to right side). Respective frequencies were 49.3% and 51.4%.

Conclusion: MB2 treatment rates may serve as a guide for practicing endodontists because they were achieved with the most current treatment techniques, advanced visualization, adequate time, and clinical expertise.