Introduction to Oral Histology

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Introduction to Oral Histology
Dr Firas Alsoleihat, BDS, PhD Department of
Conservative Dentistry
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Why do we study Oral Histology and Biology?

• To understand the structure and function of oral
  tissues.
• To understand the development of oral tissues.
• To understand the general oral physiology.
• To understand oral diseases.

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How Can We Study Oral Histology and Biology??

• Gross Anatomy
• Physical properties
• Chemical composition
• Histological sections
• Hard tissues
• Ground sections
• Decalcified Sections
• Soft Tissues

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Oral Structures

• Teeth enamel, dentine, cementum and pulp.
• Periodontium gingiva, alveolar bone,
  periodontal ligament and root cementum.
• Jaw bones.
• Tempromandibular joint.
• Oral mucosa.
• Sub-mucosa Blood vessels, Nerves.
• Salivary glands.

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Oral Structures

• Hard tissues
• Soft tissues

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Oral Structures

• Hard tissues
• Enamel
• Dentine
• Cementum
• Alveolar bone
• Jaw bones.
• Tempromandibular joint.

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Oral Structures

• Soft tissues
• Pulp.
• Gingiva
• Periodontal ligament
• Oral mucosa.
• Sub-mucosa Blood vessels, Nerves.
• Salivary glands

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Tooth structure
- A tooth has a crown and root(s) with a pulp
chamber and root canal(s). -Enamel, dentine,
pulp tissue and cementum make up a tooth.
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Enamel

• Most highly mineralized tissue in the body
• 96 inorganic material.
• Non-vital, insensitive, cannot be regenerated.

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Ground Sections
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Decalcified Sections
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Histological Sections
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Dentine

• Dentine forms the bulk of the tooth.
• It is rigid but elastic therefore ideal to
  support enamel.
• It has a tubular structure
• It is a vital, sensitive.
• Capable of repair.
• Formed throughout life.

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Dentine

• Primary dentine
• secondary dentine

• Tertiary dentine .

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Histological Sections
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The Pulp

• The pulp forms, nourishes, innervates and
  repairs dentine.
• Soft connective tissue contained within the pulp
  chamber and the root canals.

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Tooth Supporting Structures
Teeth are supported by the perodontium which
consists of 1- The gingiva 2- Root cementum 3-
Periodontal ligament 4- Alveolar bone
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The Gingiva

• The gingiva has 2 main regions
• the attached gingiva
• the free gingiva.

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Cementum

• Thin layer of calcified tissue covering the
  dentine of the root.
• Cementum varies in thickness at different levels
  of the root
• thicker at the root apex and inter-radicular
  areas.

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Cementum

• The prime function of cemntum is to give
  attachment of the tooth to collagen fibres of the
  periodontal ligament.
• Cementum can be repaired and regenerated

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Periodontal Ligament

• Dense fibrous connective tissue that attaches
  the tooth to the alveolar bone.
• The periodontal space varies according to the
  functional state of teeth.
• It is responsible for the functional position of
  the tooth eruption, support (recovery after
  heavy loads) and drift.

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Alveolar Bone

• The part of the maxilla and mandible that
  supports the teeth.
• Bone remodelling according to the functional
  demands .
• Alveolar bone requires functional stimuli to
  maintain mass, otherwise it atrophies.
• Outer and inner cortical plates
• Individual tooth sockets are separated by
  inter-dental septa.

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Jaw Bones

• The maxilla and the mandible form the upper and
  lower jaw bones.
• Histology of bone compact and spongy bone.

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Histological Sections
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Histological Sections
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Tempromandibular Joint

• The TMJ is the synovial articulation between the
  mandible and the cranium.

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Oral Mucosa

• The oral mucosa represents the lining of the
  oral cavity
• It consists of oral epithelium and an underlying
  connective tissue (lamina propria), and the
  basement membrane in between.

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Oral Mucosa

• The oral epithelium is poly-stratified squamous
  epithelium.The epithelial cells (keratinocytes)
  are arranged in layers.

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Oral Mucosa

• Depending on the location and function of the
  epithelium, the oral mucosae are classified into
  
• masticatory mucosa
• lining mucosa
• specialized mucosa.

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Masticatory Oral Mucosa

• Masticatory mucosa covers parts of the hard
  palate and the gingiva.
• the epithelium is keratinised to withstand
  masticatory forces.

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Lining Oral Mucosa

• Lining mucosa covers the lips, cheeks, alveolar
  mucosa, soft palate, ventral surface of the
  tongue and the floor of the mouth.

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Specialized Oral Mucosa
Specialized oral mucosae include 1- The
mucosa covering the dorsal surface of the
tongue. 2- The lingual tonsils. 3- The gingival
attachment to teeth. 4- The vermillion border of
the lip
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Specialized Oral Mucosa
The dorsal surface of the tongue

• Characterized by the presence of lingual
  papillae.
• Some of the papillae possess a mechanical
  function, while others have a sensory function
  (taste buds)

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Specialized Oral Mucosa
Lingual Tonsils

• Lingual tonsils are situated at the posterior
  third of the tongue, at the lateral borders.

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Specialized Oral Mucosa
Gingival attachment to the tooth

• Characterized by the presence of double basement
  membranes, one facing the connective tissue and
  the other facing the tooth.

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Oral Sub-Mucosa

• Oral sub-mucosa is a layer of loose fatty or
  glandular connective tissue.
• This layer contains major blood vessels and
  nerves supplying the mucosa and separating it
  from underlying bones and muscles..

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Salivary Glands

• Three pairs of major salivary glands and minor
  salivary glands.
• Major salivary glands
• Parotid
• Submandibular
• Sublingual

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Conclusion
It is important to understand the normal
structure, development and function of oral
structures, in order to understand the nature of
pathologies faced in clinical practice.
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course documents.
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Reference Book

1. Berkovitz B., Holland G. and Moxham B. Oral
   Anatomy, Histology and Embryology, 3rd or 4th
   edition, Edinburgh, 2005, Mosby.
2. Nanci A. Ten Cate's Oral Histology
   Development, Structure, and Function, 6th
   Edition, 2003, Mosby. Antonio, PhD
3. Bhaskar S. Orbans Oral Histology and
   Embryology, 11th edition, 1991, Mosby.

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