Related Experiment Video
Updated: Jan 19, 2026
08:12
Micro-dissection of Enamel Organ from Mandibular Incisor of Rats Exposed to Environmental Toxicants
Published on: March 29, 2018
10.6K
The hidden structure of human enamel
Elia Beniash1,2,3,4, Cayla A Stifler5, Chang-Yu Sun5
1Department of Oral Biology, School of Dental Medicine, UPitt, Pittsburgh, PA, 15261, USA.
Nature Communications
|September 28, 2019
Summary
Human enamel
Area of Science:
- Biomaterials Science
- Nanotechnology
- Biomineralization
Background:
- Enamel, the human body's hardest tissue, comprises aligned nanocrystals.
- The precise orientation of these crystals, crucial for enamel's resilience, remains poorly understood.
Purpose of the Study:
- To investigate the crystallographic orientation within human enamel rods and interrods.
- To elucidate the role of crystal mis-orientation in enamel's mechanical properties.
Main Methods:
- Analysis of crystal orientation using advanced imaging techniques.
- Molecular dynamics simulations to model crack propagation and toughening mechanisms.
Main Results:
- Enamel interrod crystals exhibit homogeneous c-axis orientation.
- Within enamel rods, adjacent nanocrystal c-axes are mis-oriented by 1°-30°, with a gradual change and overall angle spread of 30°-90°.
- Simulations confirm that crystal mis-orientation induces crack deflection, enhancing toughness.
Conclusions:
- The heterogeneous orientation of crystals within enamel rods is a key factor in enamel's exceptional resilience.
- This microstructural design provides a toughening mechanism against physical and chemical challenges.
Related Concept Videos
01:21Tooth Anatomy
2.0K
The human tooth enables us to eat a variety of foods, speak clearly, and even aid in shaping our faces. Teeth are composed of various elements that work together. Here's a detailed look at the anatomy of a human tooth.
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...
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...
2.0K
01:15Teeth
1.6K
The formation of teeth, also known as odontogenesis, is a complex process that begins in utero, around the sixth week of embryonic development. There are three stages to this process: the bud stage, the cap stage, and the bell stage.
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...
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...
1.6K
01:55Bone Structure
51.5K
Within the skeletal system, the structure of a bone, or osseous tissue, can be exemplified in a long bone, like the femur, where there are two types of osseous tissue: cortical and cancellous.
51.5K
01:18The Bone Matrix
5.5K
Bone contains a relatively small number of cells entrenched in a matrix of collagen fibers that provide an adherent surface for inorganic salt crystals. Both components of the matrix, organic and inorganic, contribute to the unusual properties of bone. Without collagen, bones would be brittle and shatter easily. Without mineral crystals, bones would flex and provide little support. This can be observed by an experiment: when the minerals of a bone are dissolved by soaking the bone in...
5.5K
01:27Compact Bone
16.1K
Most bones contain compact and spongy osseous tissue, but their distribution and concentration vary based on the bone's overall function.
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...
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...
16.1K
01:16Accessory Structures of the Skin: Hair and Hair Follicles
4.3K
Hair and hair follicles are integral components of the integumentary system. Hair is a filamentous structure composed mainly of a protein called keratin. It is found on the surface of the skin throughout the body, except for areas such as the palms of the hands and soles of the feet.
Hair is a keratinous filament growing out of the epidermis. It is primarily made of dead, keratinized cells. Hair strands originate at the epidermal penetration called the hair follicle. The hair shaft is the part...
Hair is a keratinous filament growing out of the epidermis. It is primarily made of dead, keratinized cells. Hair strands originate at the epidermal penetration called the hair follicle. The hair shaft is the part...
4.3K