Oral Anatomy: Teeth Structure and Types

Oral Anatomy

Teeth

• Structure:
  • Enamel: hardest substance in the body, outermost layer
  • Dentin: beneath enamel, makes up most of tooth structure
  • Cementum: thin layer covering root, helps anchor to bone
  • Pulp: soft tissue containing nerves and blood vessels
• Types:
  • Incisors: chisel-shaped, for biting and cutting
  • Canines: pointed, for piercing and tearing
  • Premolars: flat, for crushing and grinding
  • Molars: flat, for grinding and crushing

Gingiva and Periodontium

• Gingiva: mucous membrane covering alveolar bone and surrounding teeth
• Periodontium: tissues supporting teeth, including:
  • Gingiva
  • Periodontal ligament (PDL): connective tissue attaching tooth to bone
  • Cementum
  • Alveolar bone: bone surrounding tooth socket

Tongue and Lips

• Tongue:
  • Muscle responsible for manipulating food during mastication
  • Covered in papillae, which house taste buds
• Lips:
  • Orbicularis oris muscle: responsible for closing and puckering lips
  • Important for speech, eating, and facial expression

Palate and Salivary Glands

• Palate:
  • Hard palate: anterior, bony portion
  • Soft palate: posterior, muscular portion
• Salivary Glands:
  • Parotid glands: largest, located near ear
  • Submandibular glands: located under jawbone
  • Sublingual glands: located under tongue
  • Functions: saliva production, digestion, and oral health maintenance

Oral Anatomy

Teeth

• Enamel is the hardest substance in the body and forms the outermost layer of the tooth.
• Dentin makes up the majority of the tooth structure and lies beneath the enamel.
• Cementum is a thin layer covering the root of the tooth and helps anchor it to the surrounding bone.
• Pulp is the soft tissue containing nerves and blood vessels.
• There are four main types of teeth: incisors, canines, premolars, and molars.
• Incisors are chisel-shaped and used for biting and cutting.
• Canines are pointed and used for piercing and tearing.
• Premolars are flat and used for crushing and grinding.
• Molars are also flat and used for grinding and crushing.

Gingiva and Periodontium

• The gingiva is a mucous membrane that covers the alveolar bone and surrounds the teeth.
• The periodontium consists of tissues that support the teeth, including the gingiva, periodontal ligament, cementum, and alveolar bone.
• The periodontal ligament is a connective tissue that attaches the tooth to the surrounding bone.

Tongue and Lips

• The tongue is a muscle responsible for manipulating food during mastication.
• The tongue is covered in papillae, which house taste buds.
• The orbicularis oris muscle is responsible for closing and puckering the lips.
• The lips are important for speech, eating, and facial expression.

Palate and Salivary Glands

• The palate consists of a hard, bony portion (hard palate) and a soft, muscular portion (soft palate).
• There are three main types of salivary glands: parotid, submandibular, and sublingual glands.
• The parotid glands are the largest and located near the ear.
• The submandibular glands are located under the jawbone.
• The sublingual glands are located under the tongue.
• The salivary glands produce saliva, which aids in digestion and maintains oral health.

Dental Embryology

Tooth Development

• Tooth development begins at 6 weeks in utero and continues until 12-14 years old
• Odontogenesis involves three stages: initiation, morphodifferentiation, and histodifferentiation
• Initiation stage occurs at 6-8 weeks, involving tooth bud formation
• Morphodifferentiation stage occurs at 8-12 weeks, involving tooth shape and size formation
• Histodifferentiation stage occurs from 12 weeks to birth, involving dental tissue differentiation

Tooth Structure

• Enamel is the hardest substance in the body, formed from ectoderm
• Dentin is formed from mesoderm and makes up most of the tooth
• Cementum is formed from mesoderm and covers the root of the tooth
• Pulp is formed from ectoderm and contains nerves and blood vessels

Mastication Physiology

Chewing Process

• Mastication is the process of breaking down food into smaller particles
• The three stages of mastication are fast chewing, slow chewing, and terminal stage
• Fast chewing occurs in the first 10-15 seconds, involving rapid contractions to break down food
• Slow chewing occurs from 15-30 seconds, involving slower contractions to grind food
• Terminal stage occurs from 30 seconds to 1 minute, involving final contractions to prepare food for swallowing

Muscles of Mastication

• Temporalis muscle elevates the mandible (lower jawbone)
• Masseter muscle elevates and protrudes the mandible
• Medial pterygoid muscle elevates and rotates the mandible
• Lateral pterygoid muscle depresses and rotates the mandible

Salivary Gland Function

Salivary Glands

• There are three pairs of salivary glands: parotid, submandibular, and sublingual
• Parotid glands produce serous (watery) saliva
• Submandibular glands produce mixed serous and mucous saliva
• Sublingual glands produce mucous saliva

Saliva Composition

• Saliva is composed of 99% water, 1% electrolytes, proteins, and enzymes
• Enzymes present in saliva include amylase, lipase, and lysozyme
• Saliva functions include lubrication, digestion, antimicrobial properties, and pH buffering

Periodontal Physiology

Periodontal Tissues

• Gingiva is a mucous membrane surrounding the base of the teeth
• Periodontal ligament is a connective tissue attaching the tooth to surrounding bone
• Cementum covers the root of the tooth
• Alveolar bone surrounds the tooth root

Periodontal Functions

• Periodontal tissues provide support for the tooth
• Periodontal tissues protect the tooth from trauma and infection
• Periodontal tissues attach the tooth to surrounding bone

Learn about the different parts of a tooth, including enamel, dentin, cementum, and pulp, as well as the different types of teeth, such as incisors, canines, premolars, and molars.