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Dental Anatomy


The Jaws and Dental Arches


The teeth are arranged in upper and lower arches. Those of the upper are called maxillary; those of the lower arch are called mandibular.

The mandible is a horseshoe shaped bone which articulates with the skull by way of the temporomandibular joint, or the TMJ.


Dentition
Dentition is a term that describes all of the upper and lower teeth collectively.

Clinically, there are three types of dentitions:

The primary dentition consists of 20 teeth in all: ten upper and ten lower. Primary teeth are also called 'baby teeth, deciduous, or 'milk' teeth. Primary teeth begin to appear at about six months and are entirely replaced by permanent teeth by 12 to 13 years of age.

The mixed dentition is the stage from ages 6 to 12  and is composed of both primary and permanent teeth.

The permanent dentition is composed of 32 teeth in all, 16 upper and 16 lower.



Types of dentition


Homodont - Teeth that differ from each other only in size. All of the teeth in the dentition look alike; for example, the alligator.


Heterodont - Most mammals, including humans, develop distinctive classes of teeth that are specialized based on their location in the mouth.


Anodontia - Anodontia is the developmental absence of teeth; for example, anteaters (zot zot). In humans, anodontia occurs as a pathological condition.


Monophyodont - Some mammals--such as seals and walruses have a single set of teeth.


Diphyodont - Most mammals, including humans, have two sets of teeth.


Polyphyodont - Describes the continual generation of teeth; most reptiles and fish fall into this category.



Classes of Teeth 


Anterior teeth


Incisors - Four uppers and four lowers.


Canines - Two upper and two lower. They function with the incisors to support the lips, cut or shear food, and as guideposts in occlusion. Essentially, they're the cornerstones of the dental arch.


Posterior Teeth


Premolars - Also known as bicuspids. There are four in the upper arch and four in the lower arch. They function with the molars in the mastication of food and in maintaining vertical dimension (the height of the face).


Molars - There are six in the upper arch and six in the lower (designated as first, second, or third).  Molars are important in the mastication of food and in maintaining vertical dimension. Upper molars have three roots ; lower molars have two roots.



Parts of the Tooth


Crown - The anatomical crown is the portion of a tooth covered by enamel. The clinical crown is the portion of the tooth actually visible in the mouth.


Root - The anatomical root is the portion of the tooth that is covered with cementum. The clinical root is that part of the anatomical root that is actually embedded in the jaw.



Layers of a Tooth


Enamel - The protective outer surface of the crown. It’s the hardest substance in the body.


Dentin - Located in both the crown and root, it makes up the bulk of the tooth; it lies beneath the enamel and cementum and provides the outer lining of the pulp chamber.


Cementum - Covers the surfaces of the root.


Pulp - The central, innermost portion of the tooth.



Dental Orientation


Median line - an imaginary line that bisects the dental arch at the center.


Mesial - toward the center (median) line of the dental arch.


Distal - away from the center (median) line of the dental arch.


Occlusal plane - A plane formed by the cusps of the teeth (the chewing surfaces).


Mesial surface - toward the midline.


Distal surface - away from the midline.


Proximal - the surface of a tooth that's adjacent to another tooth in the arch.


Facial - toward the cheeks or lips.


Buccal -  facial surface of posterior teeth (toward the cheeks).


Labial -  facial surface of anterior teeth (toward the lips).


Lingual - toward the tongue.


Incisal - cutting edge of anterior teeth.


Occlusal - the biting surface of a tooth.


Apical - toward the apex, the tip of the root.



 We're out participating at educational conventions and seminars throughout the year and we'd like to use this blog as a dental resource for our community of Phoenix, AZ (and beyond). Of course, we welcome you to join the conversation. Suggest topics and ask those burning questions about dentistry that keep you up at night. Please feel free to contact me through the Morse Family Dental  website. Remember, the advice provided here is intended to aid you in understanding some of the treatment options available. It is important to note that before beginning any course of treatment you should always see your dentist. 

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Location: Phoenix, AZ 85085, USA

Comments

  1. UnknownJanuary 17, 2017 at 6:28 PM

    This is awesome I'm trying to become a Dentist in Surprise and this list of terms will really help me nail the vocab!

    ReplyDelete

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