Gingiva and Gingival Sulcus
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Gingiva and gingival sulcus Zsolt Lohinai DMD, PhD university adjunct Semmelweis University Dept. of Conservative Dentistry [email protected] Periodontium Gingiva Periodontal ligaments Root cementum Alveolar bone Summary/integration Knowledge of normal morphology and structural biology is a prerequisite for understanding pathology and causal therapy! Summary/integration, clinical aspects, DMD vs. DDS GINGIVA The gingiva is a protion of the oral mucosa. Covers the alveolar bone and the cervical part of the teeth. It is firm in consistency and not mobile. Specially adaptated to the masticatory functions. Free gingival margin (gingiva marginalis) Attached gingiva (gingiva propria) Interdental papilla Mucogingival line GINGIVA Pink and tight Interdental papilla has one vestibular and one oral portion separated by the concave col region Gingival sulcus or crevice Narrow groove surrounding the tooth !!! Gingival sulcus or crevice The dentogingival interface The gingival sulcus is an area of potencial space between a tooth and the surrounding gingival tissue Outer (lateral) wall: sulcular epithelium of the free gingiva Inner wall: enamel of the tooth crown (cementum) Bottom: junctional epithelium of the free gingiva In clinically healthy gingiva it is only a virtual space or more frequently a less than 2 mm deep fissure around the teeth !!! Significance of the gingival sulcus Discontinuity in the epithelial lining - breakage in barriers - medical aspects - locus minoris resistenciae - periodontal seal ! Battle for the solid surface between host and bacteria The teeth are nonshedding, solid surfaces, which provide a solid substratum for bacterial colonization and spreading into the deeper tissues The modified lining epithelium is firmly attached to the tooth, forms a strutural barrier against plaque bacteria In periodontitis there is an apical migration of the epithelial cells and periodontal breakdown and consequent conversion of gingival sulcus into an infected periodontal pocket The epithelial components of the gingiva Oral epithelium Multi-layer stratified squamous epithelium Stratum corneum: keratinized layer Stratum granulosum: electrondense keratohyaline and glycogen containing granules, less and less nucleus Stratum spinosum: simplier IC stucture, less mitochondria and Golgi, more desmosomes Stratum basocellulare: basal layer, cell division, connection to basal membrane by hemidesmosomes, fibrills (VII-type coll.) Non keratinocytes: melanocytes and Langerhans cells Oral epithelium Oral epithelium str. spinosum tonofilaments Epithelial cells desmosomes Intercellular space Oral epithelium basic features When traversing the epithelium from the basal layer to the epithelial surface, the keratinicytes undergo continuous differentiation and specialization Keratinized outer mechanical és microbiological defendig layer Impermeability for water soluble materials Strong connections to subepithelial connective tissue Turnover (4 weeks) Width of attached gingiva has a clinical significance: Protect the tooth/implant vs. gingiva interface! Minimum width of 2 mm is necessary to maintain perio health! Height: thin or thick biotype, inflammatory response, impression taking The epithelial components of the gingiva, sulcular epithelium Sulcular epithelium basic features Lateral wall of the sulcus Non-keratinized Relative impermeability to fluids and cells; good resistance to mechanical forces Increased lysosomal activity The epithelial components of the gingiva, junctional epithelium Junctional epithelium basic features A collar like modified epithelial ring around the neck of the teeth Epithelial attachment to the tooth, sealing Non-keratinized, there are no separated layers, stratum basale (facing the CT) & suprabasale (fasing the tooth), the cell axis is parallel with axis of the tooth, from couple to appr. max. 30 layers Two basal lamina (inner to tooth/outer to CT) Increased permeability (wide intercellular spaces, few intercellular connections) Main route of leukocytes toward the sulcus Fast turn over (7 days) Junctional epithelium Inner basal membrane Outer basal membrane Epithelial attachment apparatus capillary plexus Capillar pl. Inner and outer basal lamina omatin lagen fiber ementum Epithelial attachment apparatus The hemidesmosome of DAT cell Tonofilament-bullous pemphigoid antigens (collagenous protein type VIII)-? Tonofilament-integrin- laminin The components of IBL are synthetized by DAT cells in the absence of the immediate vicinity of CT DAT cell turnover The DAT cells divide and migrate The daughter cells replace the generating cells on the tooth surface Gradually migrate coronally, eventually break off into the sulcus Junctional epithelium in the antimicrobial defense Quick cell exfoliation Strong funelling effect Basement membrane barrier Production of antimicrobial substances (beta- defensins, lysosomal enzymes: proteinases, MMP) Secretion of chemokines (IL, TNF, cytokines) attract and activate professional defense cells (PMN, lymphocytes) !!! Importance and production of crevicular fluid (GCF) GCF is basicly a transudate of varying composition found in the sulcus/periodontal pocket between the tooth and the marginal gingiva GCF passing through the relatively wide intercellular spaces of SE and JE into the sulcus (by oncotic/capillary pressure gradient – leukocytes by chemotatic factors!) and provides nutrients for DAT cells to grow At the gingival sulcus the GCF become contaminated so that agents from the oral cavity challenge the most coronal DAT cells Blood supply of the gingiva From periodontal ligaments (mainly) From alveolar process From subperiosteal plexus !!! Function of crevicular fluid In healthy sulcus the amount of GCF is very small – normal maintenance of function of epithelium – composition: IS fluid- like, epithelial cells, leukocytes, bacteria During inflammation the GCF flow increases and resembles that of an inflammatory exudate – host defense by flushig bacterial colonies and their metabolites away from the sulcus - composition: 1) inflammatory exudate: plasma-like exudate, prostaglandins, cytokines, complement system, lysozyme, alkaline phosphatase, cathepsin, lactoferrin etc. 2) bacteria, bacterial metabolites/enzymes: endotoxins, hydrogen sulfide, butyric acid, collagenases, proteases, hyaluronidase etc. 3) products of tissue breakdown: lactate dehydrogenase, polyamines, collagen peptides etc. GCF amount and composition – rapid diagnostic test !!! Periotron Metabolite: PGE2, Inflammatory cytokines: IL, TNF Catabolic tissue enzymes: collagenase, protease, Host vs. bacteria Battle for solid tooth surface! Colonization of GR- bacteria Degeneration and detachment of DAT cells Conversion of sulcus into pocket Periodontal tissue breakdown Bacterial infection Periodontitis is NOT a civilisation disease! Its incidence is smaller in developed contries Endogenous infection (sugar, anaerobic environment, recolonization) Depth of pocket determines the composition of bacterial flora – bacterial complexes Vertical and horizontal bacterial transmissions Bacteria vs. host defense lines 1st: saliva 2nd: gingival sulcus 3rd: connective tissue of the gum 4th: systemic immune response Immune cells traffic to the periodontium 1. Plaque antigen diffuse through the JE 2. Langerhans cells capture and process the antigen 3. Antigen presenting cells leave the gingiva in the lymphatics 4. In the lymph node they stimulate the lymphocytes to produce a specific immune response 5. Antibodies travel back to the gingiva via blood vessels, leave the circulation in the exsudate and carried to the plaque in GCF 6. Periodontally specific B and T cells proliferated in the lymph nodes home back to the periodontium and begin there humoral and cell mediated immune activities Clinical aspects The proper plaque-controll is the base of periodontal health: so the gingival massage alone no, just the plaque removal is effective (interdental brush, floss) In case of gingivitis/periodontitis the volume of sulcular fluid (GCF) is increased, composition is altered - diagnostic possibility !!! Clinical aspect Probing of healthy gingiva 0.2 N force - till junctional epithelium Probing may under or overestimates the depth of sulcus Clinical aspect Probing of inflammed gingiva Bleeding? Till the resistant collagen fibers or till the alveolar bone Clinical aspect of probing Visual exam with probing depths Periodontal probing chart !!! Finishing line position Clinical aspects Finishing line position of the dental restaurations: 1) Supragingival (preferably) 2) Paragingival 3) Subgingival - intracrevicular (above JE) - temporary expanding the sulcus for impression material - the deeper the finishing line the greater risk to iatrogen dental attachment loss! Never violate the biologic width! !!! Biologic width Clinical aspect Biologic width (on average 2.04 mm) is the distance between the bottom of the sulcus and the top of the alveolar crest, including the JE (0.97 mm) and CT attachment (1.07 mm) to the root surface of a tooth. This distance is important to consider when fabricating dental restorations, because they must respect the natural architecture of the gingival attachment if harmful consequences are to be avoided. When dental restorations violate biologic width, chronic inflammation of the periodontium and unpredictable loss of alveolar bone will occur untill the biologic width is restored by tissue breakdown The ultimate goal is to maintain the insulation