Three-Dimensional Observation of the Pulp Cavity of Mandibular First Molars by Micro-CT

Aim: To observe the age-related three dimensional morphological and quantitative changes in the pulp cavity and root canal orifices of mandibular first molars by Micro-CT. Methodology: In each age group(20's, 40's and 60's), ten mandibular first molars without any substance defects or caries were examined using Micro-CT. The pulp cavity of each tooth was reconstructed in three dimensions. Then, the volume ratio of the pulp cavity and the diameter and angle of root canal orifices were examined. Results: With age, the volume ratio of the pulp cavity decreased, and the diameter of root canal orifices also decreased. With regard to the root canal angle in the orifice region, the angle of the mesio-buccal and mesio-lingual root canals decreased, but there was no marked change in that of the distal root canals. Conclusions: The morphology and volume ratio of the pulp cavity of the mandibular first molar changed with age. The morphological changes of the orifice region were particularly specific. The angle of mesio-buccal and mesio-lingual root canal increase was age-related, but with the distal root canal, the degree of change was small and insignificant.