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Dental Terminology
Dental Terminology
The teeth emerge in the mouth through a process called eruption. Eruption is the movement of teeth through the alveolar bone and gingival tissues. Teeth erupt at different times in a person's life.
Partial eruption is the term given to teeth that have not fully emerged but are in the process of eruption. There may be times when a tooth does not fully erupt because there is insufficient room for a new tooth to emerge. The tooth that does not erupt is considered to be impacted.
Dentition
The development and arrangement of teeth in the mouth is called dentition. There are three different dentition stages:
Primary Dentition
Primary Dentition
Forms in the womb
Begins eruption in children 6 - 8 months old
Consists of 20 teeth which usually complete eruption by the age of 3
Also referred to as deciduous or baby teeth
Mixed Dentition
Mixed Dentition
This is the transition period when a child has some primary teeth and some permanent teeth
Begins around age 6
Continues until around age 12, when all primary teeth are lost
Permanent Dentition
Permanent Dentition
Usually begins to erupt at the age of 6
Continues to erupt until around age 21
Consists of 32 teeth designed to last a lifetime
Are commonly referred to as adult teeth
Note: In the example above, 4 teeth are missing (third molars).
Maxillary Arch (Upper Arch)
Maxillary Arch (Upper Arch)
The upper arch
Is a fixed structure that is part of the skull
The abbreviation is MAX or MX
Mandibular Arch (Lower Arch)
Mandibular Arch (Lower Arch)
The lower arch is hinged with the temporal bone of the skull at the temporomandibular joint, commonly known as TMJ
The abbreviation is MAND or MD
Midline
Midline
The imaginary line drawn through the middle of the face and head, dividing it into two equal parts. It separates the two arches into two identical left and right halves.
Quadrants
Quadrants
Each dental arch is divided into a right and left quadrant. The quadrants are formed by the midline, which divides the arch in half. There are two quadrants per arch that divide the mouth into four equal sections.
Lettering and Numbering Systems
When working in a dental practice, it is important to be able to differentiate between primary and permanent teeth. Therefore, all teeth are assigned a letter or number to identify them. This lettering/numbering system is universal.
The primary dentition uses a lettering system, and the permanent dentition uses a numbering system. The mixed dentition uses both letters and numbers to identify the teeth, based on the dentition stage of the tooth (primary or permanent).
Primary Dentition Lettering System
Primary Dentition Lettering System
The primary dentition's lettering system begins in the upper arch with the most posterior (back), upper right tooth. Lettering begins with the letter A and continues from the patient's right to left around the upper arch, then drops down to the lower arch and ends in the lower right quadrant with the letter T.
Permanent Dentition Numbering System
Permanent Dentition Numbering System
Similar to the path for primary dentition, the permanent dentition's numbering system begins in the upper arch with the most posterior (back), upper right tooth. Numbering begins with the number 1 and continues from the patient's right to left around the upper arch, then drops down to the lower arch and ends in the lower right quadrant with the number 32.
Note: In the example above, tooth #1, #16, #17, and #32 are missing.
Orthodontic Lettering and Numbering System
Orthodontic Lettering and Numbering System
For team members that work in an orthodontic practice, orthodontia uses a different numbering system from the rest of dentistry.
Primary teeth are lettered A through E
Permanent teeth are numbered 1 through 8
The numbering system is quadrant based, starting at the front and then moving to the back for each quadrant.
Note: In the permanent teeth example, tooth #8 is missing from each quadrant.
Time for review!
Dental Terminology Basics Quiz
Module 1
Module 1
Dental Anatomy Basics
Module 3
Module 3
Tooth and Surface Location
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