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Tooth surfaces:

1. Anteriors - All anterior teeth exhibit four surfaces and one edge on their crowns. They are named as follows:

a. Mesial - The surface toward the midline.

b. Distal - The surface away from the midline.

c. Labial -The "outside" surface which is toward the lips.

d. Lingual - The "inside" surface which is toward the tongue. In the maxillary arch, the lingual surface is sometimes called the palatal surface.

e. Incisal edge (or ridge) - The biting edge.

2. Posteriors - All posterior teeth exhibit five surfaces on their crowns:

a. Mesial, distal, and lingual - These surfaces may be defined like the corresponding surfaces of anterior teeth.

b. Buccal - The "outside" surface which is toward the cheek, and corresponds to the labial surface of the anterior teeth. The term facial surface may be used for either the labial surface of anterior teeth or the buccal surface of posterior teeth.

c. Occlusal - The chewing surface.

3. Roots - Root surfaces are named exactly like the surfaces of crowns, except there is no incisal edge or occlusal surface. The termination or tip of the root is termed the apex (Plural - apices).

4. Proximal - This term refers to any surface between two teeth, so proximal surfaces, by definition, are normally only mesial or distal surfaces.

SURFACES

SURFACES

Distal •«•y Iron atdlllM

D. Line angle - The line, or angle formed by the junction of two crown surfaces, and its name is derived by combining the names of those two surfaces.

When naming line angles and point angles, the names of the surfaces are combined by dropping the "al" from the end of the first surface and substituting an "o." Where two "o's" are adjacent, they are separated by a hyphen. There are thus eight line angles on each tooth, and they are listed as follows: 1. Line angles of anterior teeth:

mesiolabial labioincisal roesiolingual linguoincisal distolabial mesioincisal distolinsual distoincisal

2. Line angles of posterior teeth:

mesiobuccal bucco-occlusal mesiolingual linguo-occlusal distobuccal disto-occlusal distolingual mesio-occlusal

E. Point angle - The point which is the junction of three crown surfaces, and takes the name of those three surfaces.

1. Point angles of anterior teeth:

mesiolabioincisal mesiolinguoincisal distolabioincisal distolinguoincisal

2. Point angles of posterior teeth:

mesiobucco-occlusal mesiolinguo-occlusal distobucco-occlusal distolinguo-occlusal

Thirds of crown and root:

1. Crown - The crown surfaces of teeth are divided into artificial thirds, both horizontally and vertically. These thirds are named by their location, according to the surface which is being viewed. For example, the mesial crown surface of an anterior tooth exhibits labial, middle and lingual thirds, when divided vertically. When divided horizontally, this same mesial crown surface has incisal. middle, and cervical thirds.

2. Root - The root, from any aspect, is divided into horizontal thirds only, which are termed cervical, middle, and apical thirds. The term "cervical" denotes toward the cervix, or neck of the tooth, or in other words, toward the cervical line. The cervical thirds of the root and crown are thus adjacent to each other and are separated by the cervical line.

Anterior Tcxrth Anterior Tooth

Mesial Aspect Labial Aspect

Anterior Tcxrth Anterior Tooth

Mesial Aspect Labial Aspect

Posterior Tooth PMtertor Tooth

Mesial Aspect Buccal A«P«ct

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