Introduction - Nomenclature

Dentition

The development and arrangement of teeth in the mouth; also refers to the arrangement of natural or artificial teeth whether in single or multiple sets.

Deciduous Dentition

Also called milk teeth, baby teeth, temporary teeth, primary teeth, and juvenile teeth; consists of 20 teeth that erupt from approximately 6 months to 3.5 years of age.

Permanent Dentition

Also called secondary dentition and adult teeth; consists of 32 teeth that erupt from approximately 6 to 21 years of age.

Deciduous Dentition Classes

Central incisor, lateral incisor, canine, first molar, and second molar.

Permanent Dentition Classes

Central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar, and third molar.

First Permanent Molar

Erupts at approximately 6 years of age; also called the 6-year-old molar and is the biggest molar.

Second Permanent Molar

Erupts at approximately 12 years of age; also called the 12-year-old molar.

Third Molar

Also called the wisdom tooth; completes eruption between approximately 17–21 years.

Transitional Phase

Also called mixed dentition or the “ugly duckling” stage; the period when deciduous and permanent teeth are present at the same time, commonly around 6–12 years of age.

Succedaneous Teeth

Permanent incisors, canines, and premolars that succeed and take the place of the deciduous predecessors.

Accessional Teeth

Teeth that erupt by themselves rather than replacing deciduous predecessors; includes the first, second, and third molars.

Mandible

The lower jaw, made up of a single pair of bones.

Maxilla

The upper part of the jaw that is fixed in the cranium.

Pre-maxilla

Bones present at the front of the maxillary jaw; also referred to in the lecture as the area of the incisors.

Dental Arch

The part of the jaw that gives attachment to the root portions of the teeth and holds the teeth in position relative to each other.

Maxillary Arch

The dental arch of the upper jaw.

Mandibular Arch

The dental arch of the lower jaw.

Midline

An imaginary line dividing the center of the face into two equal parts and dividing the upper and lower arches into quadrants.

Quadrant

One side of the jaw.

Quadrant 1

Maxillary right quadrant.

Quadrant 2

Maxillary left quadrant.

Quadrant 3

Mandibular left quadrant.

Quadrant 4

Mandibular right quadrant.

Alveolus

The bony socket or hole in which an individual tooth is set; it is part of the bone surrounding the tooth and provides attachment for the ligament.

Anterior

The front portion of the teeth, composed of incisors and canines/cuspids.

Posterior

The back portion of the mouth, consisting of premolars and molars.

Inferior

Toward the feet or caudal direction.

Superior

Toward the head or cranial direction.

Concave / Prognathism

Curved inward like an hourglass; in the lecture, the lower jaw is out and the upper jaw is in.

Convex / Retrognathism

Curved outward like a football; in the lecture, the lower jaw is in and the upper jaw is out.

Monorooted Tooth

A tooth with a single root; examples include incisors, canines, and the second premolar.

Birooted Tooth

A tooth with two roots; examples include mandibular molars and the maxillary first premolar.

Trirooted Tooth

A tooth with three roots; characteristic of maxillary molars.

Incisors

Teeth composed of central and lateral incisors with sharp edges; there are four per arch and two per quadrant; their functions include cutting, biting, and shearing food.

Cuspid / Canine

The third tooth from the midline, with a pointed cusp; there is one canine per quadrant and two per arch; functions include cutting, tearing, piercing, and holding.

Bicuspids / Premolars

Teeth with two cusps; there are two per quadrant and four per arch; functions include cutting, tearing, crushing, holding, and grinding.

Molars

Posterior teeth located at the back portion of the mouth; generally consist of 4–5 cusps and function primarily in grinding and chewing.

Homodont

“Same teeth”; animals having one single type of dentition in which the teeth are similar in shape; found in fishes, amphibians, and reptiles.

Heterodont

“Different teeth”; animals having more than one type of tooth morphology with different shapes and sizes; examples include humans and dogs.

Monophyodont

Animals with only one set of teeth for the rest of their life; examples in the lecture include crocodiles and reptiles.

Diphyodont

Animals with two sets of teeth, deciduous and permanent; examples include humans, cats, and dogs.

Polyphyodont

Animals with multiple sets of teeth that can be replaced multiple times; examples include fishes, sharks, and whales.

Hypsodont

Teeth that are long and crowded; the lecture gives horses as an example.

Bunodont

Molars with cusps that are low and rounded rather than sharp and peaked.

Secodont

Teeth with enlarged or blade-like teeth.

Mammalian Primary Dental Formula

I 2/2, C 1/1, M 2/2; the lecture identifies this as the 10-tooth primary dentition formula.

Mammalian Permanent Dental Formula

I 2/2, C 1/1, P 2/2, M 3/3; the lecture identifies this as the 16-tooth permanent formula per quadrant.

Tooth Numbering System

A system used for good communication and ease of task in writing and record-keeping.

Zsigmondy/Palmer Notation System

A symbolic tooth-numbering system using a grid to represent the tooth quadrant; developed by Adolph Zsigmondy in 1861 and Corydon Palmer in 1870.

Universal Notation System

Tooth-numbering system associated with Julius Parreidt (1882) and Cunningham (1883); approved by the American Dental Association in 1968.

Universal Permanent Numbering

Numbers permanent teeth from 1–32.

Universal Deciduous Numbering

Uses letters A–T for deciduous teeth.

FDI System

Fédération Dentaire Internationale system, also called the two-digit system; developed by Dr. Jochen Viohl in 1966 and accepted as an international standard by ISO 3950.

FDI First Digit

Indicates the quadrant; 1–4 are used for permanent dentition and 5–8 for deciduous dentition.

FDI Second Digit

Indicates the tooth within the quadrant; 1–8 for permanent dentition and 1–5 for deciduous dentition.

Viktor Haderup Notation System

A European tooth-numbering system similar to Zsigmondy-Palmer notation that uses + and − signs to indicate tooth position.

Haderup Right Quadrant

The + or − sign is placed at the right side of the tooth.

Haderup Left Quadrant

The + or − sign is placed at the left side of the tooth.

Advantage of Zsigmondy-Palmer

Easy to use and easy for beginners.

Disadvantages of Zsigmondy-Palmer

Cannot be decoded into a computer; only one number is used to designate a particular tooth; no provision for identifying supernumerary teeth; difficult for verbal transmission.

Advantages of Universal Notation

A separate number or alphabet is given to each individual tooth; easy to visualize and easy to communicate.

Disadvantages of Universal Notation

Can be confusing compared with Palmer and FDI; difficult to remember; does not clearly consider the jaw quadrant.

Advantages of FDI

Simple, accurate, easy to memorize, user-friendly, helps differentiate left/right, arches, and tooth type, easy for computer input, simple in conversation and direction, and readily communicable in print.

Disadvantages of FDI

Difficult to memorize and confusing for deciduous teeth; can be difficult to understand or define teeth; difficult to enter multiple teeth in different arches.

Advantages of Viktor Haderup

Computer-friendly and easy to understand.

Disadvantages of Viktor Haderup

Can be confusing for recording and difficult to dictate; cannot be used routinely.