What Are Teeth Made Of? Tooth Composition and Mineral Content

The Basic Structure and Composition of Teeth

Teeth are complex structures made up of multiple tissues and minerals that each serve a specific purpose. Although the type and arrangement of teeth vary by species, all teeth contain the same basic building blocks. Understanding tooth anatomy and composition gives insight into how these remarkable structures are designed for specialized functions.

Enamel

Enamel is the hardest substance in the human body. It covers the visible crown portion of the tooth and protects the sensitive inner structures. Enamel is made of tightly packed hydroxyapatite crystals that give it incredible strength. It lacks collagen and does not replenish itself once worn or damaged.

Dentin

Underneath the enamel layer is dentin, a bonelike tissue that makes up the bulk of each tooth. It contains microscopic tubules that radiate outward from the pulp chamber to the dentinoenamel junction. These dentinal tubules contain fluid and nerve endings, making dentin sensitive to stimuli.

Pulp

At the center of the tooth is the pulp chamber, which contains soft connective tissue, blood vessels and nerves. Together, the pulp, blood vessels and nerves are called the dental pulp. The dental pulp provides nutrients to the tooth and allows it to sense hot/cold temperatures or pain.

Cementum

A bone-like substance called cementum covers the dentin surface of the tooth root. It anchors the periodontal ligaments that hold the tooth in place within the jawbone. Cementum regenerates slowly to compensate for wear during tooth function over a lifetime.

Periodontal Ligaments

The periodontal ligaments are bundles of connective tissue fibers that attach the cementum on the tooth root to the alveolar bone within the jaw socket. The network of ligaments hold the teeth securely in place and enable teeth to withstand the forces of biting and chewing.

The Makeup of Different Types of Teeth

While all teeth contain the same basic parts, the structure varies significantly between different types of teeth that perform specialized jobs. The composition of enamel, dentin and cementum also varies by tooth type.

Incisors

Incisors are the sharp, chisel-shaped front teeth used for cutting into food. They have thicker enamel on the front surface and their roots are single-canaled. Incisors contain more enamel than other tooth types.

Canines

Canines, or cuspids, are the pointed teeth on either side of the incisors. They have extremely long roots to anchor them firmly for tearing and gripping food. The crown of canines is covered in enamel and the root in cementum.

Premolars

The two premolar teeth on each side are a transition between canines and molars. Premolars have two cusps for shearing and crushing. They have thicker dentin and less enamel compared to incisors and canines.

Molars

Broad, flat molars at the back are used for grinding food with their multiple rounded cusps. They contain the thickest enamel but have the smallest amount of pulp. The roots tend to branch more than other tooth types.

Tooth Development and Mineral Composition

Teeth begin forming while still in the embryonic and fetal stages. Tooth development involves complex interactions between epithelial cells from the primitive oral cavity and mesenchymal cells from the neural crest. The timing and sequence of tooth mineralization during development determines the composition of the tissues.

Enamel Formation

Enamel is produced by ameloblasts, which secrete proteins that mineralize to form rod-like enamel prisms made of hydroxyapatite crystals. The proteins dictate the orientation of the prisms. Mature enamel contains almost no organic material.

Dentin Composition

Odontoblasts create the dentin organic matrix which then mineralizes with hydroxyapatite crystals. Unlike enamel, dentin continues to form gradually throughout life. The ratio of minerals to organic material is 70% to 20% in dentin.

Cementum Deposition

Cementoblasts produce and mineralize cementum on the tooth root. Cementum is 45-50% mineralized material, primarily hydroxyapatite crystals embedded in a matrix of collagen fibers. Cementum remodeling allows the tooth to accommodate chewing forces.

Key Minerals and Proteins in Tooth Composition

Although composed mostly of the mineral hydroxyapatite, teeth also contain specialized organic materials, water and other minerals that support the structure and function of each part.

Hydroxyapatite

Hydroxyapatite is a crystalline calcium phosphate mineral that gives teeth their incredible strength. Enamel is over 95% hydroxyapatite, while dentin and cementum contain 70% and 50% hydroxyapatite respectively.

Collagen

Collagen fibers make up the organic matrix that holds hydroxyapatite crystals together. The type I collagen in dentin and cementum provides elasticity and complex inner architecture. Enamel has no collagen.

Water

Water composes about 10% of enamel, 15% of dentin and 23% of cementum by weight. Water occupies microscopic spaces in the mineralized matrix and helps distribute pressure placed on the teeth.

Other Minerals

Enamel, dentin and cementum also contain tiny amounts of other minerals like magnesium, sodium, potassium, chloride and carbonate. These minerals play roles in the solubility and structural stability of the tissues.

Age Changes Tooth Structure and Composition

The makeup of teeth shifts over time. Enamel loses minerals, dentin tubules enlarge, pulp declines, and cementum thickens with aging. Understanding age-related changes in tooth anatomy and composition provides insight into maintaining lifelong dental and oral health.

Enamel Wear

While enamel does not change much past eruption, its mineral content decreases gradually over many decades of use due to subtle dissolution. Dietary acid and friction also lead to enamel thinning and wear.

Dentin Changes

Age-related changes to dentin include tubule enlargement, increased mineralization, decreased elasticity and pulp narrowing. These changes make the tooth more brittle and prone to cracks and fractures with age.

Reduced Pulp

The pulp cavity and blood supply becomes smaller over time. This reduction makes the tooth less vital and more susceptible to infections. The nerves may become less responsive to stimuli.

Cementum Deposition

Cementum continues to deposit with age, making the root thicker and more bulbous. While this provides stability, it can lead to a condition called hypercementosis in some individuals.

Impact of Diet on Tooth Composition

Proper nutrition provides the key building blocks for maintaining the mineral composition and structural integrity of teeth throughout life. Dietary deficiencies or excesses can negatively impact tooth structure over time.

Calcium and Phosphorus

Adequate calcium and phosphorus allow proper mineralization and regeneration of enamel and dentin. Deficiencies impair development and lead to defects and weakness.

Vitamin D

Vitamin D promotes calcium absorption and the mineralization of tooth matrices. A lack of vitamin D causes enamel hypoplasia and salivary gland atrophy, increasing decay risk.

Fluoride

Fluoride incorporates into forming enamel and makes teeth more resistant to acid and decay. Excess fluoride during enamel formation causes dental fluorosis.

Sugars and Acids

Frequent exposure to dietary sugars and acids dissolves tooth minerals. Loss of hydroxyapatite, especially from enamel, permanently weakens the structure and increases susceptibility to cavities and erosion.

Tooth Structure Informs Dental Care

Knowing what teeth are made of and how their composition changes over time guides proper oral care and dental treatments. Good home care and professional services can help maintain the anatomy and structural integrity of teeth throughout life.

Brushing and Flossing

Removing bacterial plaque through brushing and flossing is crucial for preventing decay and inflammation that destroys tooth structures. Using a fluoride toothpaste also reinforces enamel.

Protecting Teeth

Since enamel cannot regenerate, protecting teeth from trauma and limiting acidic/sugary foods prevents permanent damage to the mineralized structure that cannot be reversed.

Prompt Dental Care

Getting decay treated early keeps it small and manageable. Waiting causes larger lesions that may impact inner tooth layers, require more extensive repairs, or lead to tooth loss.

Regular Dental Cleanings

Professional cleanings remove mineralized tartar that can only be accessed by tools. Tartar is damaging to enamel and causes gum inflammation. Cleanings enhance home care.

In summary, the complex anatomy and specialized composition of different teeth types reflect the incredible precision of nature’s design for optimizing their crucial functions.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.