Dental Anatomy: A Comprehensive Guide to Tooth Structure and Function
Tooth Histology
From a histological point of view, the tooth is made up of 4 tissues: 3 hard tissues (enamel, dentin, and cementum) and one soft tissue (dental pulp), which is rich in vascularization and innervation, giving it great sensitivity.
The two external hard tissues are enamel, located on the crown (top) of the tooth, and cementum, located on the root (bottom). Dentin is located inside, delimiting the dental pulp. The visible portion of the crown is involved in chewing and is a hard tissue that supports significant pressure.
Details of the Tissues:
- Enamel: The outermost tissue of the tooth crown, with high translucency, white or yellowish color, and a smooth, shiny surface. Its hardness is the greatest in the body, and it does not regenerate.
- Dentin: A bulky tissue that increases with age, both within the same tooth and overall.
- Cementum: Located at the root, covering the dentin.
- Pulp: The soft tissue, the only place where cells appear.
- Periodontal Ligament: Not part of the tooth itself, but it keeps the tooth attached to the bone.
The Faces of the Tooth
The tooth is divided into two main faces: buccal and lingual/palatal.
- Buccal Faces: Those directed towards the cheeks (vestibule).
- Palatal Faces: Those facing the oral cavity in the upper jaw.
- Lingual Faces: Those facing the oral cavity in the lower jaw.
The last two faces are the incisal edge of the incisors and canines, and the occlusal surface of premolars and molars.
Architectural Elements of Teeth
- Cusp: A pyramid-shaped structure with its base attached to the body of the tooth.
- Tubercles: Small cusps added to the normal anatomical structure.
- Groove: A break in the tooth surface, excavated in the tooth.
Dental Groups
Incisors are for cutting, canines for tearing, and premolars and molars for grinding. All teeth have some chewing ability, and all are capable of performing the two main functions of mastication.
Types of Dentition
Humans have two dentitions: temporary (primary/baby teeth) and permanent (adult teeth).
- Primary Dentition: Consists of 20 teeth: 10 in the upper arch and 10 in the lower arch. This includes 2 central incisors, 2 lateral incisors, 2 canines, and 4 molars.
- Permanent Dentition: A normal adult mouth has 32 teeth: 16 in the upper arch and 16 in the lower arch. This includes 2 central incisors, 2 lateral incisors, 2 canines, 4 premolars, and 6 molars.
Anatomy of the Jaws and Mouth
The mouth has three important functions: communication with the outside world, breathing, phonation, taste, and chewing.
Masticatory System
This consists of the dentition and the jaws where the teeth are implanted.
Stomatognathic System
A set of elements that form the mouth, whose function is chewing, swallowing, taste, phonation, and articulation of sounds. It consists of bone structures that support the oral cavity and soft tissues that differentiate the walls:
- Anterior Wall: Lips
- Posterior Wall: Soft palate and fauces
- Superior Wall: Vault (hard palate)
- Inferior Wall: Tongue and floor of the mouth
- Lateral Walls: Cheeks
Salivary Glands
- Parotid Glands: Located on the side of the ramus of the mandible. They drain the wall of the cheeks at the level of the upper molars and produce serous saliva.
- Submandibular Glands: Located on the inner surface of the mandible on each side. Their main channel opens into the mucosa and produces mixed saliva (a mixture of serous and mucous).
- Sublingual Glands: Situated in the thickness of the floor of the mouth. Their secretion is poured onto the floor of the mouth (mucus).
Limits of the Oral Cavity
- Anterior Wall (Lips): Membranous folds of muscle, most strikingly red or pink.
- Superior Wall: Formed by the vault.
- Hard palate
- Soft palate (no bone support and composed of soft tissue)
- Posterior Wall: Formed by the soft palate and fauces.
- Inferior Wall: Formed by the tongue and floor of the mouth. The tongue is involved in multiple functions (sense of taste, swallowing). Its upper surface is responsible for collecting taste buds.
- Vallate
- Filiform
- Fungiform
Tooth Structure
Teeth are located in the alveoli of the maxillary and mandibular bones and are attached by the periodontal ligament.