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Basics of dental anatomy.

• Human Dentition: The teeth that are located in the upper and lower jaws are collectively referred to as the human dentition.
• Maxillae: The upper jaw is known as the maxillae.
• Maxillary Teeth: The teeth located in the maxillae form an arch and are referred to as maxillary teeth.
• Mandible: The lower jaw is called the mandible.
• Mandibular Teeth: The teeth located in the mandible are referred to as mandibular teeth.

Dentition

• As humans, we have two sets of teeth during our lifetime.
• Primary Dentition: The first set of teeth we get. These are often referred to as baby teeth. There are 20 teeth in the primary dentition.
• Permanent Dentition:The second set of teeth we get. These are often referred to as adult teeth. There are 32 teeth in the permanent dentition.
• There are several terms that help to define locations on and around the teeth. These terms are used often to refer to specific areas of the mouth when describing conditions there.
• Posterior: Towards the back of the mouth.
• Anterior: Towards the front of the mouth
• Mesial: Towards the midline of the mouth.
• Distal: Away from the midline of the mouth
• Buccal: Any area on the cheek side of the teeth
• Lingual: Any area on the tongue side of the teeth
• Facial:Any area on the cheek or lip side of the teeth. Is often used interchangeably with buccal but mostly in the anterior portion of the mouth.
• Palatal: Any area on the tongue side of the maxillary teeth
• Occlusal: Any area on the chewing surfaces of back teeth.
• Incisal: Any area on the biting surfaces of the front teeth

The Four Parts of A Tooth

• Each tooth in the mouth contains four different tissues that serve different functions. The teeth are made up of two major parts: the crown and the root.
• The crown of the tooth is what is visible in the mouth
• The root of the tooth is the portion which normally not visible in the mouth and is anchored within the bone (Figure 2). Within each tooth, the four different tissues that are present are the enamel, the dentin, the pulp and the cementum.
• Enamel: Makes up the protective outer surface of the crown of the tooth.
• Dentin: Makes up the majority of the inner surface of the tooth. It cannot normally be seen except on x-rays.
• Pulp: This is the area inside the tooth that holds the nerves and blood vessels of the tooth. It is in the centre of the tooth and is in both the crown and the root of the tooth.
• Cementum: Makes up the outer surface of the root of the tooth. It is much softer than enamel.

Tooth Identification

• In both the maxillary and mandibular arch there are similar teeth. There are four types of teeth in both arches. These include the incisors, the canines, the premolars and the molars. Each of these teeth is located in a different area of the mouth and serve different functions.
• Incisors: The four front teeth in the mouth are known as incisors. They are located in both the maxillary and mandibular arches. The two centre teeth are known as central incisors and the teeth on either side of them are known as lateral incisors. All of these teeth are responsible for cutting or biting food. They act like scissors.
• Canines: The teeth located distal to the lateral incisors are known as canines. These teeth form the corners of the mouth. There are 2 canines in the maxillary arch and 2 canines in the mandibular arch. These teeth are responsible for tearing food particles when chewing.
• Premolars: The teeth located distal to the canines are known as premolars. There are 4 premolars in each arch and two are located behind each canine in the arch. These teeth are smaller than the molars and are responsible for crushing food in the chewing process. These teeth are also only present in the permanent dentition. The primary dentition only consists of incisors, canines and molars.
• Molars: There are normally 6 molars in each arch; three on the left and three on the right side. They are referred to as first, second and third molars. Some people never develop third molars and often these are the molars that are so far back in the mouth that they have difficulty coming in and may have to be taken out. The role of the molars in chewing is to grind the food.

Tooth Numbering Systems

• In order to effectively and efficiently refer to teeth we often use numbering or lettering systems. There are several systems that are used throughout the world. These include the Universal Numbering System, the Palmer Notation System and the International Numbering System.
• The most widely used system in the U.S. dental schools is the Universal Numbering System. This consists of assigning numbers to the teeth in the permanent dentition from 1 to 32 starting with the upper right third molar and continuing over to the upper left third molar and then down to the lower left third molar and onto to the lower right third molar. For example The the mandibular right canine tooth would be tooth #27
• Using the Universal Numbering System the the primary dentition is identified using letters. Beginning at the second molar on the upper right, the teeth in the maxillary arch are assigned letters : Then continuing with the mandibular left second molar and around to the mandibular right the second molar, the teeth are assigned letters K:T

Conclusion

• The teeth have two major parts, the crown and the root. When looking at a cross-section of the tooth the four main tissues that make up the tooth are the enamel, the dentin, the cementum and the pulp. All of these parts play important roles in the proper functioning of the dentition.
• The primary dentition is made up of 20 teeth, while the permanent or adult dentition contains 32 teeth. Most dental professionals refer to numbering or lettering system when identifying the teeth. There are four main types of teeth, the incisors, the canines, the premolars and the molars. Each type of tooth serves a different function in eating. Understanding dental anatomy is essential in order to begin to develop an appreciation for the role of teeth indigestion, appearance, speech and sensory input. Without the proper function of the teeth, usually due to disease such as decay or cavities, a person's health, appearance and nutrition can be affected.