What are the Parts of a Tooth?

The Parts of a Tooth

Knowing the parts of a tooth can help you understand what your family dentist or orthodontist is describing to you.  Here is a list of some of the parts of a tooth.

Enamel – Enamel is the outside layer of the tooth that is very, very hard.  We create a lot of pressure when chewing our food.  Pounds of pressure.  Enamel does wear over time and wear facets can be seen if a patient grinds their teeth.  Most people grind their teeth at night and a night guard can protect their teeth from excessive wear.  A night guard is a hard plastic retainer, worn on the upper, that covers the occlusal surfaces of the teeth and protects them.  You wear down the plastic night guard and not your enamel.  Take care of your enamel by not chewing on hard foods or ice.  Enamel does not have any sensitivity or nerve endings.  Enamel can have the color combination of yellow, white and grey and can also be translucent to a degree.

Dentin – Dentin is right underneath the enamel and is a large part of the crown and  roots.  This is a hard structure that does have nerve fibers.  The nerve fibers radiate from the pulp into small tubules in the dentin.  Dentin is usually more yellow than enamel.  If a cavity forms, sometimes the dentin will give us a clue that there is a problem.  When a cavity forms, the dentin will try to repair the area by creating more dentin.  Even if a cavity does not form, the dentin will form over a life time inside the tooth and cause the pulp chamber and pulp canals to get smaller with time.

Pulp –  The pulp is a soft red tissue that has nerves fibers and blood vessels.  The nerves can give us signals that a cavity is forming or that we have a cracked tooth.  A cracked tooth will hurt when a patient bites down on food and the vertical crack opens up resulting in a sharp pain.  Since a crack in a tooth is hard to detect, a plain orthodontic band can be placed on the suspected tooth to see if it really is cracked.

Cementum – Cementum is a layer of hard material that covers the roots.  It is slightly softer than dentin.  Cementum has gum tissue fibers, called sharpy fibers, attached to it to hold the tooth into position and to withstand chewing forces.  Cementoblasts maintain the cementum around the roots.

Periodontal Ligament – The periodontal ligament (PDL) surrounds the roots of the teeth with connective tissue fibers that hold the teeth in a sling.  The alveolar bone and the roots do not touch.  The periodontal ligament is between them.  Cells that are found in the periodontal ligament are cementoblasts and fibroblasts.    The fibers of the periodontal ligament are constantly erupting the tooth.  Therefore as the enamel of the tooth wears or if an opposing tooth is extracted, the tooth will continue to erupt until it comes in contact with gum tissue or another tooth.

Alveolar Bone – Alveolar bone is, of course, a supporting structure.  The upper alveolar bone is called the maxilla and the lower called the mandible.  The bone contains osteoblastic and osteoclastic cells that deposit and resorb bone respectively.  It is these cells that allow tooth movement with orthodontic forces.