Related Experiment Video
Updated: Aug 26, 2026
Systematic Assessment of Mammalian Skull Specimens for Dental and Temporomandibular Joint Pathology
Published on: August 22, 2022
[Agenesis and the morphology and site of other teeth in the permanent dentition]
Guo-ping Ji1, Hui-ju Cao, Sieng Weng
1Department of Orthodontics, School of Stomatology, Shanghai Second Medical University, Shanghai 200025, China. jiguoping31@yahoo.com.cn
Objective:
To Investigate the relationship among anodontia, anomalously shaped teeth and reduction of teeth crown.
Methods:
The position and the number of congenitally absent teeth of 79 patients were analysed, as well as the abnormal morphology of other teeth. The width of the remained teeth was measured and compared with that of normal on base of patients being divided into four groups by the number and the position of agenesis.
Results:
(1)Most of the congenitally absent teeth were upper lateral incisors and lower central incisors. (2) The congenitally absent teeth of upper central incisors, upper and lower first molars were rare. While in several cases, the central incisors were lightly pet-shaped. (3) There was no significant difference in teeth size between mild hypodontia groups and normal. As the incremental degree of hypodontia, anterior teeth tended to reduce, while the size of posterior teeth was relatively stable. Upper lateral incisors, lower canines, upper second premolars, upper and lower second molars accounted most in the anomalously shaped teeth which could be often found in patients with hypodontia.
Conclusion:
(1) number during evolution. (2) The developmental anomaly of teeth size, teeth morphology and teeth number might be a procedure of continuous variation and it might be different manifestation of the same mechanism.
Related Concept Videos
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...
01:21Tooth 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.
01:22Sutures of the Skull
Sutures are immobile joints between adjacent bones of the skull. The narrow gap between the bones is filled with dense, fibrous connective tissue that unites the bones. The long sutures located between the skull bones are not straight but instead follow irregular, tightly twisting paths. These twisting lines tightly...
01:29Bone Formation by Intramembranous Ossification
The process begins when mesenchymal cells in the embryonic skeleton gather together and differentiate into osteogenic cells, which then develop into...
01:09Changes in the Appendicular Skeleton with Age
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
01:24Bone Formation by Endochondral Ossification