Introduction to Oral Histology
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Transcript of Introduction to Oral Histology
Introduction to Oral HistologyDr Firas Alsoleihat, BDS, PhD
Department of Conservative Dentistry
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.
How Can We Study Oral Histology and Biology??
• Gross Anatomy
• Physical properties
• Chemical composition
• Histological sections:
• Hard tissues
• Ground sections
• Decalcified Sections
• Soft Tissues
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.
Oral Structures
● Hard tissues
● Soft tissues
Oral Structures● Hard tissues:
● Enamel● Dentine● Cementum ● Alveolar bone● Jaw bones.● Tempromandibular joint.
Oral Structures● Soft tissues:
● Pulp.● Gingiva● Periodontal ligament ● Oral mucosa.● Sub-mucosa: Blood vessels, Nerves.● Salivary glands
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.
Enamel
● Most highly mineralized tissue in the body ● 96% inorganic material.
● Non-vital, insensitive,
cannot be regenerated.
Ground Sections
Decalcified Sections
Histological Sections
● 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.
Dentine
Dentine
● Primary dentine
● secondary dentine
● Tertiary dentine .
Histological Sections
The Pulp
● The pulp forms, nourishes, innervates and repairs dentine.
● Soft connective tissue
contained within the pulp
chamber and the root canals.
Tooth Supporting Structures
Teeth are supported by the perodontium which consists of:
1- The gingiva
2- Root cementum
3- Periodontal ligament
4- Alveolar bone
The Gingiva
● The gingiva has 2 main regions:
● the attached gingiva ● the free gingiva.
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.
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
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.
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.
Jaw Bones
• The maxilla and the mandible form the upper and lower jaw bones.
• Histology of bone: compact and spongy bone.
Histological Sections
Histological Sections
Tempromandibular Joint
• The TMJ is the synovial articulation between the mandible and the cranium.
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.
Oral Mucosa
• The oral
epithelium is poly-
stratified
squamous
epithelium.The
epithelial cells
(keratinocytes) are
arranged in layers.
Oral Mucosa• Depending on the location and function of the epithelium, the
oral mucosae are classified into:
• masticatory mucosa
• lining mucosa
• specialized mucosa.
Masticatory Oral Mucosa
• Masticatory mucosa covers
parts of the hard palate and
the gingiva.
• the epithelium is keratinised
to withstand masticatory
forces.
Lining Oral Mucosa
• Lining mucosa covers the lips, cheeks, alveolar mucosa,
soft palate, ventral surface of the tongue and the floor of
the mouth.
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
Specialized Oral MucosaThe 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)
Specialized Oral MucosaLingual Tonsils
• Lingual tonsils are situated
at the posterior third of the
tongue, at the lateral borders.
Specialized Oral MucosaGingival attachment to the tooth
• Characterized by the
presence of double
basement membranes, one
facing the connective tissue
and the other facing the
tooth.
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..
Salivary Glands• Three pairs of major salivary glands and minor salivary glands.
• Major salivary glands:
• Parotid
• Submandibular
• Sublingual
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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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.: Orban’s Oral Histology and Embryology, 11th edition, 1991, Mosby.