Teeth contribute to your everyday routine — helping you chew, drink, form expressions, and speak. Besides contributing to various functions, they also determine how you look, as they influence the shape of your face.
But what are teeth made of? Do you consider them a part of your skeletal system, since they look so much like bones? This article will explain what teeth are made of to clear up any confusion.
Why Are Teeth Not Considered Bones?
While teeth and bones have physical similarities like being hard and white and chemical similarities like containing calcium, teeth are not bones.
And while people wonder why it is important to know whether they are similar or not, it is actually quite important. The distinction will help you understand how they heal and how to care for them in order to maintain your overall health.
The biggest difference is that bones are living tissues, while teeth are not.
Bones are composed of the mineral calcium phosphate and the protein collagen. These tissues are constantly regenerating and remodeling throughout your life.
Old tissue breaks down to give way to newer tissue. If a bone is damaged or broken, cells will rush to the area to begin repair and regeneration. Bones also have blood cells that produce bone marrow.
As teeth are dead cells, they do not regenerate or repair. While teeth are made of the strongest substance in the body, the enamel, they are weak in the sense that they have no nerves and are incapable of repairing themselves. So, once you have a deep cavity, it is permanent damage to your teeth that cannot be repaired. Also, they do not have marrow, nor do they produce cells.
What Are Teeth Made Of?
Human teeth start developing in the womb. By the age of 6 months, the baby starts having its primary teeth, and by the age of 12 years, it has shed its primary teeth to make way for secondary teeth. These teeth remain through adulthood.
As mentioned earlier, teeth do not have regenerative properties, so once they are damaged, nothing can be done to regenerate them.
The human tooth can be sectioned into three parts — the crown, neck, and root. The crown is the visible 2/3rd portion of the teeth. The neck is a very small portion between the crown and the root, and the root is the 1/3rd invisible portion of the tooth. It is embedded in the gums and is the support system of the teeth.
Anatomy Of A Tooth
Human teeth are composed of four layers of dental tissues. Three of these layers are hard tissues — enamel, dentin, and cementum — while the fourth is a soft tissue called pulp.
Enamel is a hard, calcified tissue that surrounds the crown. It covers the dentin surface and acts as a protective covering.
The thickness of enamel is different in different regions of the tooth, with the cuspal region of the premolars and molars having the thickest layer. The neck of the tooth has the thinnest layer of enamel.
Enamel color ranges from white to gray to yellow and is largely determined by genetics. The color represents staining and the degree of mineralization of the tooth surface.
Enamel is made up of organic substances , inorganic substances, and water. They have a concentration of 1%, 95% to 98%, and 1% to 4% respectively.
The organic substance is enamelin, while the inorganic substance mainly consists of phosphate and calcium ions. The ions combine to form hydroxyapatite crystals with high tensile strength and will let the enamel perform masticatory functions.
The dentin is just below the enamel. While the enamel covers it at the crown, the cementum covers it at the roots. It forms most of the tooth’s structure and gives the tooth its general form.
Dentin is a living tissue made from odontoblasts cells. These cells make dentinal tubules, small tubules that are functional units of dentin present at the cementoenamel junction.
It is a bone-like tissue that is slightly elastic and compressible. As it is a living tissue, it is susceptible to infection, cavities, and even hot and cold sensitization.
Dentin is a yellow-colored structure that consists of 30% organic and 70% inorganic matter. The inorganic component is very similar in composition to enamel; however, the hydroxyapatite crystals found in this layer are way smaller than the enamel. This makes dentin softer.
The cementum acts like a cementing substance, attaching the tooth and the bone surrounding it. It completely covers the root of the tooth and connects to the enamel at the cementoenamel junction.
It is a bone-like structure made up of 45% inorganic and 55% organic compounds. The inorganic portion consists mainly of phosphate and calcium ions, while the organic portion is mainly made up of protein polysaccharides and type 1 collagen.
The core of a tooth is made of soft living tissues called the pulp. The pulp found in the roots is called radicular pulp, and the pulp found in the crown is known as coronal pulp.
The pulp is rich in blood vessels, fibroblasts, neurons, vascular tissue, and macrophages. The pulp maintains the tooth’s vitality and has odontoblast cells that produce dentin.
Other teeth-related parts include:
Gingiva or gums: The soft tissue that protects and covers the roots of the teeth and the teeth that haven’t come out.
Pulp Chamber: The space where the pulp fits is known as the pulp chamber.
Jawbone: The alveolar bone that surrounds the tooth’s root is known as the jawbone.
Periodontal Ligament: It connects the teeth to the jaw through a system of collagenous connective tissue fibers.