Authors: Hartwell G, Bellizzi R.
Title: Clinical investigation of in vivo endodontically treated mandibular and maxillary molars.
Journal: J Endod
Date: Dec 1982
Citation: 8(12):555-7
Category: Anatomical Considerations
Evidence-based Ranking: 4
Purpose/ Objectives: To investigate obturated root canals in vivo that had been clinically treated.

Materials & Methods: 1,976 clinically treated molars were reviewed. The findings were then tabulated and recorded.

Results: Mandibular molars consisted of 847 first molars and 416 second molars. Mandibular first molars having four canals comprised 35.1% and 5.5% for second molars with a combination of 25%. Maxillary molars consisted of 538 first molars and 176 second molars. Maxillary first molars having four canals comprised 18% and 9.6% for second molars with a combination of 16.4%.

Author’s Conclusion: Access opening should be modified to enhance the likelihood of locating a fourth canal in maxillary molars.