Anatomy of the PeriodontiumAnatomy of the PeriodontiumPeriodontiumPeriodontiumThe tissues that surround and support theThe tissues that surround and support theteeth are known as the periodontium.teeth are known as the periodontium.It includes:It includes:1. Gingiva1. Gingiva2. Periodontal ligament2. Periodontal ligament3. Alveolarbone3. Alveolarbone4. Cementum4. CementumPeriodontium: peri = around . odontous =Periodontium: peri = around . odontous =toothtoothPeriodontics: the art and science ofPeriodontics: the art and science ofstudying the periodontium.studying the periodontium.Periodontist: specialist in periodonticsPeriodontist: specialist in periodontics
Gingiva:Gingiva:The fibrous investing tissue coveredThe fibrous investing tissue coveredbyby keratinized epithelium. The gingiva is onekeratinized epithelium. The gingiva is oneofof the soft tissues that line the oral cavity.the soft tissues that line the oral cavity.All the soft tissue in the mouth are KnownAll the soft tissue in the mouth are Knownas theas thethe oral mucosa, it isthe oral mucosa, it isdivided into three different types:divided into three different types:
Types of gingiva:Types of gingiva:1.1. Marginal gingiva (free orMarginal gingiva (free orunattached)unattached)2.2. Attached gingiva (firmlyAttached gingiva (firmlyattached to underlying toothattached to underlying toothand bone)and bone)3.3. Inter-dental gingiva( locatedInter-dental gingiva( locatedbetween adjacent teeth.between adjacent teeth.4.4. Gingival sulcusGingival sulcus
Clinical featuresClinical featuresMicroscopic featuresMicroscopic features
• 1:Enamel.1:Enamel.• 2:gingival margin.2:gingival margin.• 3:gingival sulcus.3:gingival sulcus.• 4:free gingival groove.4:free gingival groove.• 5:lveolar bone.5:lveolar bone.• 6:CEJ6:CEJ• 7Cementum7Cementum• 8:PDL8:PDL• Between 2 and 4 is free gingivaBetween 2 and 4 is free gingiva
Gingival sulcus:Gingival sulcus:** It isashallow fissureIt isashallow fissurebetweenbetween marginal gingival andmarginal gingival andtheenamel or cementum.theenamel or cementum.** Clinical normalClinical normalgingivalgingival sulcusdepth = 2-3 mmsulcusdepth = 2-3 mmmeasured with periodontalmeasured with periodontalprobe.probe.
Interdental gingiva:Interdental gingiva:• Its that part of the gingiva that occupy theIts that part of the gingiva that occupy theinter-proximal space, created by adjacent teethinter-proximal space, created by adjacent teethin contact. Therefore, shape determined byin contact. Therefore, shape determined bycontact relationship with teeth, and width ofcontact relationship with teeth, and width ofproximal surfaces.proximal surfaces.• If the contours are flat, interproximalIf the contours are flat, interproximalcontacts, the gingiva will be narrow andcontacts, the gingiva will be narrow andshort. If the proximal contours are moreshort. If the proximal contours are moreconvex with a small coronally positionedconvex with a small coronally positionedcontact area, the interdental gingiva will becontact area, the interdental gingiva will bebroad and high.broad and high.
The interdental gingiva can beThe interdental gingiva can bepyramidal and have col shape.pyramidal and have col shape. Buccolingual dimension the inter-Buccolingual dimension the inter-dental gingival terminates coronally withdental gingival terminates coronally withseparate buccal and lingual peaks ofseparate buccal and lingual peaks oftissueasthegingival col.tissueasthegingival col.
Gingival Groove (4):Gingival Groove (4):It is a shallow, v-shaped orIt is a shallow, v-shaped orindentation that is closely associatedindentation that is closely associatedwith apical extent of freegingiva.with apical extent of freegingiva.
The understanding of clinical features ofThe understanding of clinical features ofperiodontium is enhanced by a knowledgeperiodontium is enhanced by a knowledgeof histological component of tissue.of histological component of tissue.
Microscopic (Histological)Microscopic (Histological)FeaturesFeatures• The gingiva consist of central core ofThe gingiva consist of central core ofconnective tissue covered by stratifiedconnective tissue covered by stratifiedsquamous epithelium.squamous epithelium.
Layers of Squamous epitheliumLayers of Squamous epithelium
SulcularEpithelium:SulcularEpithelium:It lines the gingival sulcus facingIt lines the gingival sulcus facingthe tooth similar to oral epitheliumthe tooth similar to oral epitheliumexcept the 2except the 2ndndlayer (it lacks granularlayer (it lacks granularcell layer)cell layer)It acts as semipermeable membrane fromIt acts as semipermeable membrane fromthe bacteria and tissue fluid from thethe bacteria and tissue fluid from thegingivaseepsinto thesulcus.gingivaseepsinto thesulcus.
Junctional Epithelium:Junctional Epithelium:Forms the core of epithelium. It isForms the core of epithelium. It isthickest in coronal part. Is single or multiplethickest in coronal part. Is single or multiplelayer of non-keratinized cells adhering to toothlayer of non-keratinized cells adhering to toothsurface and face the gingiva by means of basalsurface and face the gingiva by means of basallamina.lamina.• Basal Laminaconsist of:Basal Laminaconsist of:LaminalucidaLaminalucidaLaminadensalLaminadensal
Details of the sulcular junctional epithelium areasDetails of the sulcular junctional epithelium areas
Connective Tissue:Connective Tissue:Is known as the lamina propria. DividedIs known as the lamina propria. Dividedinto two layers: (1) the papillary layerinto two layers: (1) the papillary layeradjacent to epithelium, (2) reticular layer,adjacent to epithelium, (2) reticular layer,contiguouswith theperiosteum.contiguouswith theperiosteum.– Lamina propria consist of:Lamina propria consist of:• Collagen fibersCollagen fibers• Intercellular ground substanceIntercellular ground substance• CellsCells• Blood vesselsBlood vessels• NervesNerves
Histological charecterstics of the gingiva(FaciolingualHistological charecterstics of the gingiva(Faciolingualsection of the periodontium)section of the periodontium)
The collagen fibers help to hold the marginal gingivaThe collagen fibers help to hold the marginal gingivatightly against the tooth and provide a firm junction oftightly against the tooth and provide a firm junction ofthe attached gingiva to the underlying tooth root andthe attached gingiva to the underlying tooth root andalveolar bone.alveolar bone.Thefibersaregrouped:Thefibersaregrouped:1. Gingivodental1. Gingivodental2. Circular2. Circular3. Transeptal3. Transeptal4. Alveolo gingival4. Alveolo gingival5. Inter-radicular fibers5. Inter-radicular fibers6. Intra-papillary fibers6. Intra-papillary fibers
The most prominent cells found in theThe most prominent cells found in thegingival connective tissue:gingival connective tissue:1. Plasmacells1. Plasmacells2. Fibroblasts2. Fibroblasts3. Mast cells3. Mast cells4. Lymphocytes4. Lymphocytes
VascularSupply:VascularSupply:It’s derived from the branches of theIt’s derived from the branches of thesuperiorand inferioralveolararteries:superiorand inferioralveolararteries:1. Greater palatineartery1. Greater palatineartery2. Buccal artery2. Buccal artery3. Sublingual artery3. Sublingual artery4. Mental artery4. Mental artery
The lymphatic drainage usuallyThe lymphatic drainage usuallyfollows the blood supply, the majorfollows the blood supply, the majorportion of the lymph drainage from theportion of the lymph drainage from thegingiva going to the submandibulargingiva going to the submandibularlymph nodes.lymph nodes.
Gingival Fluid:Gingival Fluid:The gingival (crevicular) fluid isThe gingival (crevicular) fluid iscontinually secreted from the gingivalcontinually secreted from the gingivalconnective tissues into the sulcus throughconnective tissues into the sulcus throughthesulcular epithelial wall.thesulcular epithelial wall.This fluid helps to mechanically cleanThis fluid helps to mechanically cleanthe sulcus and in addition, possess anti-the sulcus and in addition, possess anti-microbial properties and antibodies thatmicrobial properties and antibodies thatenhance the resistance of the gingiva toenhance the resistance of the gingiva togingivitis.gingivitis.
Gingival contour:Gingival contour:The inter-dental gingiva is generallyThe inter-dental gingiva is generallypointed. However, the contours of thepointed. However, the contours of thegingiva vary depending upon the shape ofgingiva vary depending upon the shape of thetheteeth, the buccolingual position of theteeth, the buccolingual position of theteeth in the arch, and the size of the inter-teeth in the arch, and the size of the inter-proximal embrasurespace.proximal embrasurespace.
Gingival Consistency:Gingival Consistency:Usually resilient and firm because of theUsually resilient and firm because of thedense collagenous nature of the gingivaldense collagenous nature of the gingivalconnectivetissue.connectivetissue. Gingival Surface Texture:Gingival Surface Texture:Being stippled like an orange peel orBeing stippled like an orange peel orsmooth and shiny. Degree of stipplingsmooth and shiny. Degree of stipplingvaries considerably among patients and invaries considerably among patients and indifferent partsof thesamemouth.different partsof thesamemouth.
Nerve Supply:Nerve Supply: Derived from maxillary and mandibularDerived from maxillary and mandibularbranchesof thetrigeminal nerve.branchesof thetrigeminal nerve.
Periodontal ligamentPeriodontal ligament• Connective tissue around and attach teethConnective tissue around and attach teethto the alveolar bone.to the alveolar bone.• Consist of bundles of fibers, according toConsist of bundles of fibers, according totheir directions:their directions:1)Alveolar crest group1)Alveolar crest group2)Horizontal group2)Horizontal group3)Oblique group.3)Oblique group.4)Apical fibers.4)Apical fibers.
• The ends of the princible fibers areThe ends of the princible fibers areembeded in cementum on the tooth sideembeded in cementum on the tooth sideand in the alveolar bone proper on theand in the alveolar bone proper on theopposite side. The embeded portions ofopposite side. The embeded portions ofthe princible fibers are the Sharpey’sthe princible fibers are the Sharpey’sfibersfibers
The physical functions of pdlThe physical functions of pdl• Transmission of occlusal forces to the bone.Transmission of occlusal forces to the bone.• Attachment of the teeth to the bone.Attachment of the teeth to the bone.• Maintainance of the gingival tissues in theirMaintainance of the gingival tissues in theirrelationship to the teeth.relationship to the teeth.• Resistence to the impact of occlusalResistence to the impact of occlusalforces(shock obsorption).forces(shock obsorption).• Provision of a soft tissue casing(to protectProvision of a soft tissue casing(to protectvessels and nerves from injury by mechanicalvessels and nerves from injury by mechanicalforces).forces).
Cementum:Cementum: Calcified tissue covers the root of the teethCalcified tissue covers the root of the teethand provide attachment to the periodontaland provide attachment to the periodontalligament.ligament. Consist of collagen fibers in a groundConsist of collagen fibers in a groundsubstance consist of 45-50% inorganicsubstance consist of 45-50% inorganicmaterials. 50-55% organic materialsmaterials. 50-55% organic materials
Width vary from 60-68 microns in coronalWidth vary from 60-68 microns in coronalthird 150-200 micronsin apical third.third 150-200 micronsin apical third. Width increase with age. 95 microns atWidth increase with age. 95 microns atageage 20. 215 micronsat age6020. 215 micronsat age60 Two types of cementum a cellular (coronalTwo types of cementum a cellular (coronalportion of the root) Cellular apical portionportion of the root) Cellular apical portionof root and in furcation areas of multi-of root and in furcation areas of multi-rootedrooted teeth.teeth.
Cemento Enamel JunctionCemento Enamel Junction::The area where cementum and enamelThe area where cementum and enamelmeet (cervical area).meet (cervical area).Threedifferent relationship:Threedifferent relationship:60-50%60-50% cementum overlapsenamelcementum overlapsenamel30%30% edgeto edgeedgeto edge5%-10%5%-10% cementum fail to meetcementum fail to meetenamel resulting in exposedenamel resulting in exposeddentinedentine
• 11:dentine.2:acellular:dentine.2:acellularcementum.3:pdl withcementum.3:pdl withfibroblast.4:cementoblastfibroblast.4:cementoblast• Cellular cementum.Cellular cementum.Cementocytes within theCementocytes within thelacuna of cementumlacuna of cementum