1. DH150 LO1: Basic Tooth Anatomy

What is the whole crown of the tooth that is covered by enamel, regardless of whether it is erupted or not?

The anatomic crown.

What is the portion of the tooth visible in the oral cavity, determined by the location of the gingival margin?

The clinical crown.

What is the part of the root covered by cementum?

The anatomical root.

Define the clinical root.

The portion of the tooth not visible in the mouth and covered by bone and gingival tissue; it includes the root that is covered by gingiva.

What is the area of a two or three rooted tooth where the root divides?

A Furcation.

What is a bifurcation and a trifurcation, in terms of roots?

A bifurcation is 2 roots, and a trifurcation is 3 roots.

What is the area from the cementoenamel junction (CEJ) to the furcation called?

The Root trunk.

What is the opening at the apex of a tooth root through which the blood and nerve supply of the pulp enters the tooth?

The Apical Foramen.

What is the primary function of Incisors?

They are designed to cut.

What are the longest and most stable teeth in human dentition, and why?

The Canines; they are the most stable because they have the longest roots and resist lateral forces of displacement.

What are the two types of teeth that are considered Posterior Teeth?

Premolars and Molars.

How many incisors, canines, premolars, and molars are there in permanent dentition?

8 incisors, 4 canines, 8 premolars, and 12 molars.

Which type of tooth found in permanent dentition is absent in primary dentition?

Premolars (Primary teeth consist of 8 incisors, 4 canines, and 8 molars).

What are the five basic functions of teeth?

1) Protect the oral cavity (forms a hard physical barrier); 2) Chew food; 3) Aid the digestive system in breaking down food; 4) Necessary for proper speech and phonetics; 5) Appearance.

How many surfaces do anterior teeth have, and what replaces the fifth surface (occlusal)?

Anterior teeth have four surfaces and an incisal ridge, which is the biting edge.

How many surfaces do posterior teeth have, and name them.

Posterior teeth have five surfaces: lingual, buccal (facial), mesial, distal, and occlusal.

Which proximal surface faces away from the midline of the face?

The Distal surface.

Which tooth tissue forms the outer surface of the anatomic crown and is the hardest tissue in the human body?

Enamel.

What is the chemical composition of enamel?

96% inorganic and 4% organic and water.

Which tooth tissue forms the main portion or bulk of the tooth, underlying the enamel and cementum?

Dentin.

What is the chemical composition of dentin?

70% inorganic, 30% organic and water.

What is the bonelike substance that covers the root, is less dense than enamel or dentin, and is thickest at the apex of the root?

Cementum.

How does the inorganic component percentage correlate with the hardness of tooth tissues (enamel, dentin, cementum)?

The more inorganic matter component in a tooth tissue (Enamel 96%, Dentin 70%, Cementum 45%-50%), the harder that tooth tissue will be.

What are the specialized cells that form dentin?

Odontoblasts.

What specialized cells produce cementum?

Cementoblasts.

Which type of dentin is laid down in response to trauma or caries?

Reparative Dentin, also known as Tertiary dentin.

What are the three functions of the pulp?

Nourishing, sensory, and dentin reparative system of the tooth.

What tissue lines the walls of the pulp cavity, and what is its function?

Odontoblasts, whose function is to lay down primary and secondary dentin.

The nerve tissue in the pulp is sensory and responds only to what sensation?

Pain.

Name the three different parts of the pulp cavity.

Pulp chamber (in the crown), Pulp horns (extensions into the crown points/cusps), and Pulp canals or Root canals (in the roots).

What is the Cementoenamel junction (CEJ)?

The junction of the cementum of the root and the enamel of the crown; the anatomic line separating enamel from cementum.

What is a Line angle?

The junction of two surfaces.

What is a Point angle?

The point where three tooth surfaces meet.

Name two landmarks found only on anterior teeth.

Cingulum, and Incisal ridge.

Name three landmarks found only on posterior teeth.

Triangular ridge, Central pit, and Lingual cusp.

How many lobes does an anterior tooth have?

Four lobes: three facial (labial) and one lingual.

What is a small elevation of enamel on some portion of the crown of a tooth?

A tubercle.

What is a mound on a tooth's crown that makes up a large portion of the tooth's occlusal surface?

A cusp.

What is a cingulum, and which lobe forms it?

An elevated projection on the lingual surface of a newly erupted incisor, arising from the fourth developmental lobe.

How many molars are there on the maxilla and how many on the mandible in permanent dentition?

There are 6 maxillary molars and 6 mandibular molars (12 total).

What is the percentage of inorganic matter in cementum, and how does it receive nourishment?

45% to 50% inorganic matter; nourishment is derived from the outside of the tooth through blood vessels that come directly from the bone.

Which type of cementum covers the entire anatomical root and cannot reproduce itself, serving as part of the tooth's anchoring system?

Acellular cementum.

What is the difference between the alveolus and the alveolar process?

The alveolus is the bony socket in which the tooth fits, while the alveolar process is the portion of alveolar bone that supports the teeth.

Why is the term "bicuspid" inaccurate when referring to premolars?

The term "bicuspid" implies the tooth has only two cusps, but some premolars have three cusps on their occlusal surfaces.

How many marginal ridges are on a tooth?

Two.

If a molar has three roots, how many pulp chambers does it typically have?

One