Histology of the Gingiva PDF

Histology of the Gingiva Oral and Dental Science Sarah Balian Intended Learning Outcomes By the end of the session students should be able to: Identify and label the three anatomic areas of the gingival epithlium Describe the anatomy and function of the following structures: 1. Oral Epitheliu...

Histology of the Gingiva Oral and Dental Science Sarah Balian Intended Learning Outcomes By the end of the session students should be able to: Identify and label the three anatomic areas of the gingival epithlium Describe the anatomy and function of the following structures: 1. Oral Epithelium 2. Sulcular epithelium 3. Junctional epithelium Describe the function of gingival connective tissue Be aware that other structures are part of the gingiva - periodontal ligament, cementum and alveolar bone Please note this lecture is linked with: Histology of Periodontal Ligament Alveolar bone Cementum  4 Oral Epithelium Periodontium A Alveolar Mucosa B Mucogingival junction C Attached gingiva D Free gingival groove E Free gingiva F interdental papillae The Gingival Col Dentogingival Junction Epithelium Oral Three areas of Epithelium (Dento-gingival junction) 1. Junctional Epithelium 2. Sulcular Epithelium 3. Oral Epithelium Cell Layers of the Oral Epithelium Illustration key: KL keratinized cell layer GL granular cell layer SL superficial cell layer PL prickle cell layer BL basal cell layer Oral Epithelium Oral Epithelium The oral epithelium covers the outer surface of the free gingiva and attached gingiva; it extends from the crest of the gingival margin to the mucogingival junction. The oral epithelium is the only part of the periodontium that is visible to the unaided eye. Oral Epithelium Stratified squamous epithelium The layers are listed below in order from the deepest layer to the most superficial layer. a. Basal cell layer cube-shaped cells b. Prickle cell layer - spine-like cells with large intercellular spaces. The cells of both the basal and prickle cell layers attach to each other with desmosomes. c. Granular cell layer flattened cells and increased intracellular keratin d. Keratinized cell layer (stratum corneum): flattened cells with extensive intracellular keratin. Why does this section have the most cellular layers? Joins with underlying connective tissue in wavy pattern Sulcular Epithelium  Epithelium that faces the tooth surface Sulcular Epithelium without being in contact with the tooth surface Thin Nonkeratinized epithelium Without rete pegs Semi permeable (but less so than JE) allowing fluid to flow from the gingival connective tissue into the sulcus. This fluid is known as the gingival crevicular fluid (GCF) In health, the sulcular epithelium joins the connective tissue at a smooth interface with no epithelial ridges (no wavy junction). Junctional Epithelium  Stratified squamous Junctional Epithelium nonkeratinized epithelium Joins gingiva to tooth surface Length 0.71 – 1.35mm Cell thickness coronally – 15-30 cells Coronal – 15 – 30 cells 4 -5 cells thick at apical zone High cell turnover Apically – 4 – 5 If it is non – keratinised – what does this means cells in comparison to tissue that is keratinised? Why does a tooth need a junctional epithelium and where does it come from? Cellular layers Illustration key: KL keratinized cell layer GL granular cell layer SL superficial cell layer PL prickle cell layer BL basal cell layer Why does a tooth need a junctional epithelium and where does it come from? The body is covered by continuous sheet of epithelium Teeth penetrate this sheet by eruption thus creating an opening The body attempts to seal the opening by attaching epithelium Hence the name ‘junction’ meaning ‘connection’ Microscopic Anatomy of Junctional Epithelium Closely packed epithelial cells Connected to neighbouring cells by desmosomes (cell junction) Internal Basal Lamina –thin layer of extracellular matrix between epithelial cells and tooth surface External Basal Lamina - thin layer of extracellular matrix between epithelial cells and gingival connective tissue  Attachment to tooth surface is by hemidesmosomes (cell junction) & internal basal lamina 8-10 hemidesmosomes per micron at the coronal end and 2 per micron at apical end What does this mean? Attachment to connective tissue is by hemidesmosomes & external basal lamina Cell Junctions Desmosome Cell junction that connects two neighbouring epithelial cells and their cytoskeletons together Hemidesmosome Connects the epithelial cells to the basal lamina Functions of Junctional Epithelium Host Attachment Barrier defense Gingival Connective Tissue Gingival Connective Tissue The gingival connective tissue of the free & attached gingiva provides solidity to the gingiva and attaches the gingiva to the cementum of the root and the alveolar bone. The gingival connective tissue is also known as the lamina propria. Functions of gingival connective tissue Integrity and strength of gingival tissues – dense network Normal function of connective tissues The transportation of water, nutrients, metabolites, oxygen, etc., to and from the individual connective tissue cells occurs within the matrix Host response – immune response Supragingival fibres of connective tissue  Supragingival fibres AG Alveologingival Alveolar crest to gingival connective tissue C Circular Ring round coronally above crestal bone DG Dentogingival Cementum fan into gingival connective tissue PG Periosteogingival Fan from periosteum IG Intergingival Mesiodistal direction along whole dental arch linking teeth together IC Intercircular Encircle several teeth linking teeth together IP Interpapillary Located in the papilla connect oral & vestibular papilla TG Transgingival Cementum to CEJ and run horizontally linking teeth together TS Transeptal Cementum of one tooth to another tooth over crestal bone What is the depth of the gingival sulcus in health? What shape is the gingival sulus? Other structures Please refer to the upcoming histology sessions on the following: Periodontal Ligament Cementum Alveolar bone Image references The Mouth and Body Connection [INFOGRAPHIC] | Delta Dental of New Jersey (deltadentalnj.com) Gingiva: Types, histology and clinical aspects | Kenhub healthy gingiva | attached gingiva is non movable gingiva as the name indicates the... | Dental assistant study, Dental health, Dental (pinterest.co.uk) https://www.jaypeedigital.com/eReader/chapter/9789386261731/ch1 12: Oral Mucosa | Pocket Dentistry Chapter 6 Disturbed Tooth Eruption | SpringerLink Dale BA. Periodontal epithelium: a newly recognized role in health and disease. Periodontol 2000. 2002;30:70– 78. Will you ever look at gums in the same way again? Recommended Reading Read the following journal article Structure of periodontal tissues in health and disease. Nanci A. and Bosshardt DD. Periodontology 2000. (2006) 40:1; p11-12,25- 28 http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0757.2005.00141.x/full