Authors: HIbbard ED, Ireland RL.
Title: Morphology of the root canals of primary molar teeth.
Journal: J Dent Child
Date: Oct 1957
Citation: 24:250-257
Category: Pediatric Endodontics
Evidence-based Ranking: 5
Purpose/Objectives: To conduct a comprehensive study of the morphology of the root canals of the primary molar teeth.

Materials & Methods: 87 primary molars were used in the study. Canals were reproduced by dissolving the pulp tissue with 3%H2O2 then drying. Red colored methacrylate resin was then injected under pressure and allowed to set; teeth were then decalcified with nitric acid. The variations of the canal morphology were then observed.

Results: 1. In the mandibular primary molars the variations occur more frequently in the mesial roots. 2. Less variation exists at the time when formation is just completed. 3. Root resorption and secondary dentin deposition are responsible for the wide range of variations. 4. The 1st primary molars have combinations of 2-4 canals and the 2nd primary molars have combinations of 2-5 canals. 5. Lateral branching, connecting fibrils and apical ramifications may be encountered. 6. Root and canal fusions were common.

Author’s Conclusion: There is are large amount of variation found in the morphology of primary molars, this is most likely due to root resorption and secondary dentin deposition.