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.

http://blackboard.ju.edu.jo/

User name: danatomy_std

Password: danatomy_std

Click on course documents.

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.