ORAL HISTOLOGY AND EMBRYOLOGY

ORAL HISTOLOGY Oral Histology is the study of microscopic structure, composition, and functions of oral tissues. Oral histology describes in detail the tissues of  The teeth  Periodontium  Surrounding oral mucosa.

ORAL EMBRYOLOGY Oral embryology will deal with development of different orofacial tissue  Teeth  Face Soft tissues Hard tissue Developmental anomalies

Oral Cavity  Oval shaped space bordered by lips, cheeks palate, and floor of the mouth. Oral Cavity Proper  Space within the teeth to the oropharynx & floor of mouth.

Vestibule  Space between cheeks & lips & teeth & gingiva  Oral Vestibule is divided into Posterior sections Anterior sections Anterior Vestibule  Exists with lips closed (blow some air) this is best shown diagrammatically.

Types of oral mucosa 1. Masticatory Mucosa  Covers the hard palate,the free and attached gingiva  These areas are most used during mastication  It is firmly attached to underlying tissues  It is keratinized stratified squamous epithelial

2. Lining Mucosa  Covers the lips, cheeks, the floor of the mouth, the underside of the tongue, the alveolar mucosa: (covers alveolar process, loosely attached to bone)  The color of the buccal mucosa is pinkish, bluish/grey and may contain brown to black pigmentation = it is normal  Mucous membrane of the vestibule is thin: there are many blood vessels visible = red

 Normal color of buccal mucosa varies depending on:  vascularity  hemoglobin content,  density of CT  width of epithelium  degree of keratinization.  These tissues are not firmly attached to underlying structures  It is composed of stratified squamous epithelium NOT keratinized

3. Specialized Mucosa  Covers the dorsum (top) surface of the tongue Contains taste buds

The tongue Tongue  A mobile, muscular organ attached with its base and central part of its body to the floor of the oral cavity  Function: aids in speech, mastication, taste, deglutition (swallowing) Surfaces  DORSAL – top superior surface, fairly uniform in appearance, soft to palpation & grayish pink in color  VENTRAL – underside, inferior  LATERAL – 2 sides of tongue

Tongue papilla Papillae  The tongue mucosa of the dorsum forms numerous small elevations called papillae  Gives the tongue a very characteristic roughened surface.  Use gauze for examining the tongue  There are four types of papillae and on the tongue  Filiform  Fungiform  Circumvallate  Foliate (minute)

1. Filiform Papillae  Hair-like projections  Most numerous on anterior 2/3rd of tongue, but spread over entire tongue  Slender elongated, conical structures  Whitish, pink in color

2. Fungiform Papillae  Shaped like flat broad mushrooms with rounded pink surface  Redder (pinker) than filiform  Scattered among filiform papillae and along sides  At apex: less numerous than filiform  House taste buds (sweet, salt, sour)

Fungiform

fungiform

3. Circumvallate papillae  Form a v shaped (line) grove just anterior and parallel to the terminal sulcus  Divides the anterior 2/3 and posterior 1/3  Contains tastes buds and salivary glands

Circumvallates papillae

4. Foliate Papillae  Irregular elevated folds of mucosa on the posterior lateral border  Contains Von Ebner Glands (salivary glands)

Floor of the mouth  Also known as the Sublingual sulcus  A horseshoe shaped space (when the tongue is elevated)  Non Keratinized stratified squamous, soft, smooth  Pink in color (Vascular network, may vary in prominence)  Inferior boundary of the oral cavity proper Contains: sublingual gland, Bartholine duct (anterior to sub mandibular gland) Submandibular (Submaxillary) gland, Wharton’s duct

Floor of Floor of mouth

Dental hard tissues Teeth  Enamel  Dentine  Cementum bone