Microstructure of primary tooth dentin
Related Experiment Video
Updated: Oct 18, 2026
Microhardness Measurements on Tooth and Alveolar Bone in Rodent Oral Disease Models
Published on: April 26, 2024
D A Sumikawa1, G W Marshall, L Gee
1Division of Biomaterials and Bioengineering, University of California, San Francisco, USA.
Purpose:
This study was performed to determine variations in dentin microstructure from primary anterior teeth at specific areas and depths in relation to the dentin enamel junction, (DEJ).
Methods:
Ten freshly extracted, non-carious primary maxillary anterior teeth were sectioned to provide two 1.0 mm x 1.0 mm matchsticks extending from the DEJ to the pulp chamber--one each from the central and distal regions of each tooth. Slices were prepared at distances of 0.15, 0.8, and 1.45 mm from the DEJ. Following polishing, each slice was examined in a wet scanning election microscope, (SEM) and tubule density, tubular diameter, and peritubular width were determined at nine grid locations. Statistical analyses were carried out using multi-factor ANOVA, Tukey's multiple comparisons, and linear regression to compare rates of change for each parameter.
Results:
Tubule numerical density consistently decreased with distance from the DEJ. Decreases of 11,800 mm2/mm for canine distal matchsticks were significantly greater (P < 0.05) than the rate of 4,400 mm2/mm for canine central matchsticks. Rates for the lateral incisors were not significantly different. Tubule diameters increased with distance from the DEJ at rates of 0.28 micron/mm and 0.39 micron/mm for canines and lateral incisors, respectively, and there was a corresponding decrease in peritubular width. Microcanals or giant dentin tubules, 5-10 microns in diameter were incidently found in varying numbers in the midline of 4 of 20 teeth examined, including central and lateral incisors, but not in canines.
Conclusions:
The work shows substantial differences in the microstructure of primary dentin as compared to permanent dentin, substantial differences with location, and the relatively common occurrence of microcanals. Therefore, the area of solid dentin that is available for dentin bonding is significantly reduced, accounting for reported differences in bond strength. Such differences may be important factors in tooth sensitivity, susceptibility to trauma, and caries progression.
More Related Videos
07:07Development of a Direct Pulp-capping Model for the Evaluation of Pulpal Wound Healing and Reparative Dentin Formation in Mice
Published on: January 12, 2017
07:42Quasistatic Mechanical Testing for Computer-Aided Design and Manufacturing Occlusal Veneers Cemented to Milled Dentin Analog Material
Published on: December 20, 2024
Related Concept Videos
01:21Tooth Anatomy
The Crown, Neck, and Root
The visible part of the tooth is referred to as the crown. It's covered by enamel, the hardest substance in the human body. The crown is uniquely shaped for each type of tooth, allowing for different functions such as cutting, tearing, or grinding food.
01:15Teeth
In the bud stage, the tooth germ (an aggregation of cells) starts to form in the developing jawbone. During the cap stage, the tooth germ differentiates into enamel organ, dental papilla, and dental sac, which will later develop into the tooth's enamel, dentin and...
01:27Compact Bone
Compact bone, also called cortical bone, is the denser, stronger of the two types of bone tissue. It is found under the periosteum and in the diaphyses of long bones, where it provides support and protection. The microscopic structural unit of compact bone is called an osteon, or haversian system. Each osteon is composed of concentric rings of calcified...
01:09Spongy Bone
Spongy bone is more porous, and less dense compared to compact bone. It is composed of concentric lamellae that are arranged irregularly to form the trabecular network. In some bones, the spaces between trabeculae contain red marrow, where...
01:23Bone as Supporting Connective Tissue
Bone Matrix
Bone, or osseous tissue, is a connective tissue that has a large amount of two different types of matrix material. The organic matrix is similar to the matrix material found in other connective tissues, including some amount of collagen and elastic fibers. This gives strength and flexibility to the tissue. The inorganic matrix consists of mineral salts— mostly calcium salts— that give the...