Volume measurement of crowns in mandibular primary central incisors by micro-computed tomography

Abstract

Objective. To determine sex differences in the tissue proportions of crowns of mandibular primary central incisors in Chinese children and to quantify the volume of crown components in three dimensions using micro-computed tomography (micro-CT). Materials and methods. The specimens used in this study were 41 mandibular first deciduous incisor teeth with intact crowns (21 males and 20 females) obtained from patients between 5–6 years of age. Each specimen was scanned using micro-CT at a resolution of 0.05 mm and 3D-rendered images were created. The volume of each component of the crown was measured and examined for differences in different sex and ages. Results. The pulp chamber volume decreased with age and the volume ratio of the pulp chamber to the whole crown was significantly smaller in 6-year-olds than in 5-year-olds (p < 0.05). Conclusions. Males had significantly larger tooth crown volumes and dentin volumes than females did (p < 0.001), while the volume of enamel showed no sexual dimorphism.

Key Words::

• deciduous incisor
• micro-computed tomography
• sexual dimorphism
• three-dimensional observation
• volumetry

Acknowledgments

We are grateful to the Research Institute of Pediatric Dentistry of Tongji University of China for providing specimens for this study. We also give special thanks to Tokyo Dental College for providing the micro-CT (HMX-225).

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.