Related Experiment Video
Updated: Jun 13, 2026

Microhardness Measurements on Tooth and Alveolar Bone in Rodent Oral Disease Models
Published on: April 26, 2024
Why does fluorosed dentine show a higher susceptibility for caries: an ultra-morphological explanation
Kanchana Waidyasekera1, Toru Nikaido, Dinesh Weerasinghe
1Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate school, Tokyo Medical and Dental University, Tokyo, Japan. kanchanapgkw@yahoo.com
Background:
Chronic endemic dental fluorosis is a malformation of teeth caused by excessive ingestion of fluoride during period of tooth development. Apatite crystallites and collagen fibrils determine the caries susceptibility related properties of dentine. Information relating the effect of dental fluorosis with dentine crystallite and collagen structure is currently unavailable. This study examined structural aberrations of apatite crystallites and collagen fibrils in human fluorosed dentine.
Method:
Superficial dentine of thirty six normal (Thylstrup-Fejerskov index - 0) and thirty six severely fluorosed (Thylstrup-Fejerskov index - 7 to 9) extracted human molars from individuals living in an area which is endemic for dental fluorosis were morphologically analyzed using transmission electron microscopy with selected area electron diffraction and dynamic force microscopy.
Results:
A statistically significant enlargement in the size of crystallites was found in fluorosed dentine (p<0.05). These crystallites were not homogenously arranged. Selected area electron diffraction revealed a lower density of crystallites in fluorosed dentine. Randomly distributed collagen fibrils showed a less complex lay out in contrast to normal dentine tissue.
Conclusion:
Ultrastructure aberrations of the dentine explain the caries susceptibility of the tissue and suggest the necessity of special approach in dental caries treatment for patients with chronic severe endemic dental fluorosis.
Related Concept Videos
Tooth 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.
Teeth
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...
Immunofluorescence Microscopy
The...
The Oral Microbiota
Super-resolution Fluorescence Microscopy

