Periodontal Anatomy Part 1 PDF

Lecture # 1 Periodontal Anatomy I (Gingiva & Periodontal ligament) Reference: CARRANZA’s Clinical Periodontology 12th Edition Chapter (1) Ø The students should be able to: 8 Identify the clinical and microscopic gingival features 8 Co...

Lecture # 1 Periodontal Anatomy I (Gingiva & Periodontal ligament) Reference: CARRANZA’s Clinical Periodontology 12th Edition Chapter (1) Ø The students should be able to: 8 Identify the clinical and microscopic gingival features 8 Correlate the clinical and microscopic features in terms of color, size, shape and contour 8 Describe the functions & features of the gingival epithelium 8 State the different stages of tooth eruption 8 Recognize the nature of gingival fluid 8 Categorize the gingival fibers 8 State the different groups of periodontal fibers and identify their structures and functions 8 Compare between gingival and periodontal fibers. Dr. Aljoharah AL-Sinaidi  Periodontium Definition: tissues that invest, support & anchor the teeth in the alveolar processes. CONSISTS OF 1. CEMENTUM 2. PERIODONTAL LIGAMENT 3. ALVEOLAR BONE 4. GINGIVA Oral Mucosa 1- Masticatory ------- gingiva ------- hard palate 2- Specialized ------- dorsum of the tongue 3- Alveolar mucosa  Gingiva Definition: It is a masticatory mucosa (part of oral mucosa) covering the alveolar processes of the jaws & surrounds the necks of the teeth Function: Protection of the underlying tissues.  Gingiva/Anatomy 1 1 Interdental gingiva 2 Free gingiva 3 Attached gingiva  Interdental Gingiva n Occupies the gingival embrasure (interproximal space) n Tip & lateral borders -----------marginal gingiva n Intervening portion -------------attached gingiva  Interdental Gingiva Shape: n either pyramidal n or “col”  Interdental Gingiva n Its shape depends on the contact point & gingival recession.  Marginal (Free) Gingiva § Has a knife edge & surrounds teeth in a collar-like fashion § Free / unattached to tooth surface § Forms the soft tissue wall of the gingival sulcus § Demarcated from attached gingiva with free gingival groove  Attached Gingiva n Color: Pink n Consistency: Firm & resilient n Tightly attached to underlying bone n Resilient under compression n Stippling may/may not be present n On all teeth aspects EXCEPT palatal, it is demarcated from oral mucosa by mucogingival junction  Attached Gingiva n Its width Ø is an important clinical parameter (1). Ø variable between patients & between teeth/ patient Ø greatest width in the incisor region (max: 3.5 - 4.5 mm, mand: 3.3 - 3.9 mm) Ø least in the 1st premolar area (max: 1.9, mand: 1.8 mm)  Gingival Sulcus n Shallow V-shaped space around the tooth n Bounded by tooth & marginal gingiva. n Its depth is an important clinical parameter Ø Histologically = 1.5-1.8 mm. Ø Clinically = 2 - 3 mm  Gingival (Sulcular) Fluid n Seeps into gingival sulcus from gingival C.T. n Very significant in health & disease. n Functions: Ø Sulcus cleaning Ø Antimicrobial & antibody activity Ø Contains plasma proteins (ep. adhesion to tooth)  Gingiva Microscopic features: 1. Stratified squamous epithelium 2. Central core of connective tissue 1 2  Gingival Epithelium Types Sulcular Oral (outer) Junctional A= Oral ep. B= Sulcular ep. C= Junctional ep.  Gingival Epithelium Function: n Protection of deep structures. n Selective interchange with oral environment (proliferation & differentiation of the keratinocytes). n Its principal cell type is keratinocytes  Gingival cells n Major Cell Type n Keratinocyte n Other Cell Types n Langerhans cells n Melanocytes n Merkel cells  Keratinocyte n Proliferation: n by mitosis in the basal layer and suprabasal layers n Differentiation: n biochemical and morphologic events in the cell as they migrate from the basal layer  Other Cell Types n Langerhans cells n located at all suprabasal levels n mononuclear phagocyte (macrophage cells) n antigen-presenting cells n found in the oral and sulcular epithelium but absent in junctional epithelium n Melanocytes: n located in the basal and spinous layers of the gingival epithelium. They synthesize melanin  Other Cell Types n Merkel cells n located in the deeper layers of the epithelium and harbor nerve endings  Epithelial attachment with CT n By basal lamina which consists of n lamina lucida n lamina densa  Oral Epithelium n Covers the crest of marginal gingiva & outer surface of attached gingiva. n parakeratinized (has nuclei): prevalent n orthokeratinized (no nuclei) OK – NK - PK  Sulcular Epithelium n Lines gingival sulcus n Extends from coronal end of junctional ep. to crest of gingival margin. n Thin, non-keratinized, no rete pegs n Lacks granulosum and corneum strata n Potential to keratinize if it is exposed to oral cavity or bacteria flora is eliminated n loses its keratinization if placed in direct contact with tooth surface. n semi-permeable  Junctional Epithelium (JE) n Collar- like band n Non-keratinized n 0.25 - 1.35 mm in length. n Thickness: Ø 3-4 layers (early life) Ø 10-20 layers (increased age).  Junctional Epithelium (JE) n 2 strata: basal & suprabasal. n 2 basal laminae: n External (EBL): Ø attaches JE to gingival C.T n Internal (IBL): Ø attaches JE to tooth (epithelial attachment) Ø consists of lamina densa (adjacent to enamel) & lamina lucida (hemidesmosomes)  Junctional Epithelium (JE) n Formed by confluence of oral & reduced enamel epithelia during tooth eruption. n Restored after pocket instrumentation or surgery & formed around implants. n Its attachment to the tooth is reinforced by gingival fibers (dento-gingival, circular, trans-septal) n JE + gingival fibers = dentogingival (one functional) unit.  Gingival Connective Tissue n Also called “Lamina Propria” n It is fibrous & composed of: n Collagen fibers (60%) – Type I n Type IV, reticular and elastic fibers n Fibroblasts (5%) n Others (b.vs, nerves, matrix, other fibers, cells) n 2 layers; papillary & reticular. n High turnover rate (not as great as PDL & ep.) n Good healing & regeneration with little scarring.  Gingival Fibers n Functions: Ø Brace the marginal gingiva firmly against the tooth Ø Provide rigidity to withstand forces of mastication Ø Unite free gingiva with the cementum & adjacent attached gingiva n Arranged in 3 Groups: Ø Gingivodental Ø Circular Ø Transseptal  Gingival Fibers n The gingivodental fibers: n on the facial, lingual, and interproximal surfaces n embedded in the cementum just beneath the epithelium at the base of the gingival sulcus n extend externally to the periosteum of the facial and lingual bone  Gingival Fibers n The circular fibers: n encircle the tooth in ringlike fashion. n The transseptal fibers: n located interproximally n horizontal bundles that extend between the cementum of the adjacent teeth n between the epithelium at the base of the gingival sulcus and the crest of the interdental bone n sometimes classified with the principal fibers of the periodontal ligament. Gingivodental fibers  Cellular elements 1. Fibroblasts (65%) n synthesize collagen and elastic fibers n Regulate collagen degredation 2. Mast cells 3. Macrophages 4. Histiocytes  Cellular elements 5. Adipose cells 6. Eosinophils 7. Plasma cells 8. Lymphocytes 9. Neutrophils  Gingival Blood Supply Vessels of 1) PDL, 2) interseptal bone & 3) supra periosteal Gingival Lymphatic Drainage & Innervations Regional submaxillary lymphnodes Gingival Innervations Nerves from PDL Buccal & palatal nerves. Correlation of Clinical and Microscopic Features  Color Color: Pale pink/physiologically pigmented. Contour: Collar like scalloping fashion. Consistency: Firm & resilient. Surface texture: Stippling.  Normal Gingiva Shape: Narrow & pointed or broad interdental papillae & knife edge gingival margins Position: Covers the entire root surface Correlation of Clinical & Microscopic Features I- Color: n Coral (pale) pink n Produced by: Ø Vascular supply. Ø Thickness and degree of keratinization. Ø Presence of pigment-containing cells. n Physiological (melanin) pigmentation is more prominent in black individuals. Correlation of Clinical & Microscopic Features Attached gingiva Alveolar mucosa Color coral pink red Appearance Stippled Smooth & shiny Microscopic Thick epithelium Thin epithelium structure parakeratinized nonkeratinized Rete pegs No rete pegs Connective dense loose tissue Less blood vessels More blood vessels Correlation of Clinical & Microscopic Features II- Size: n Is the sum of bulk of cellular and intercellular elements. n Alteration in size is a common feature of gingival disease. Correlation of Clinical & Microscopic Features III-Contour (shape): n Marginal gingiva shows collar-like fashion with scalloped outline. n depends on: Ø Teeth shape and alignment. Ø Location and size of the proximal contacts. Ø Dimensions of facial & lingual gingival embrasures. u GINGIVAL TISSUE BIOTYPE Correlation of Clinical & Microscopic Features IV- Consistency: n Firm & resilient, tightly bound to the underlying bone (except the marginal gingiva). Correlation of Clinical & Microscopic Features V-Surface texture n Stippling: Ø Attached & interdental gingiva (not the marginal gingiva). Ø Extent & pattern varies among individuals & different areas of the same mouth. Ø Produced by alternate elevations & depressions in the gingival surface (rete pegs). STIPPLING Correlation of Clinical & Microscopic Features VI-Position n Refers to the level at which the gingival margin is attached to the tooth. n Teeth eruption dose not cease when teeth meet their functional antagonists but continues throughout life which is either: Ø Active eruption, movement of the teeth in the direction of the occlusal plane Ø Passive eruption, is the exposure of the teeth by apical migration of the gingiva Anatomic crown- clinical crown  Passive Eruption Gottlieb & Orban 1933 Periodontal ligament  Periodontal Ligament n a complex vascular and highly cellular connective tissue that surrounds the tooth root and connects it to the inner wall of the alveolar bone  Periodontal Ligament n It provides the principal anchoring mechanism of the tooth to the alveolar bone. n Inserts into cementum on tooth side & into alveolar bone on the opposite side. n Its most important elements are the principal fibers.  Periodontal Ligament n It is continuous with n Its width : 0.1 - 0.25 mm gingival connective and narrowest at the tissue. midpoint of the root..  Periodontal Ligament n Principal fibers: 1. Collagenous, arranged in bundles.  Periodontal Ligament n Principal fibers: 2. Follow a wavy course.  II- Periodontal Ligament n Principal fibers: 3. Arranged in 6 groups: Transseptal (7), alveolar crest(11),horizontal (12), oblique (13), apical (15) & interradicular fibers (14)  Periodontal Ligament n Principal fibers: 1.Transseptal group: extend interproximally over the alveolar bone crest and are embedded in the cementum of adjacent teeth (may be considered as belonging to the gingiva). 2. Alveolar crest group: extend obliquely from the cementum beneath the junctional epithelium to the alveolar crest. They prevent the extrusion of the tooth and resist fibers tooth movements. 3. Horizontal group: extend at right angles to the long axis of the tooth from the cementum to alveolar bone. 4. Oblique group: the largest group, extend from the cementum in a coronal direction obliquely to the bone. They transfer the vertical masticatory stresses into tension on the alveolar bone. 5. Apical group: radiate irregularly from the cementum to the bone at the apical region of the socket. 6. Interradicular fibers: fan out from the cementum to the bone in the furcation areas of multirooted teeth. Functions read text book  Periodontal Ligament Sharpey’s fibers: Are the terminal borders of the principal fibers that insert into cementum & alveolar bone.  Periodontal Ligament Cellular elements: n Include 4 cell types: n Connective tissue cells like fibroblasts (synthesize and regulate turnover of collagen), cementoblasts & osteoblasts. n Epithelial rests of malassez, remnants of Hertwig’s root sheath. n Defense cells (neutrophils, lymphocytes, macrophages, mast cells). n Cells associated with neurovascular elements.  Periodontal Ligament Ground substance: n Main components: Ø Glycosaminoglycans (hyaluronic & proteoglycans) Ø Glycoprotein (fibronectin & laminin) n Cementicls that may develop from: Ø Cementum or bone traumatically displaced. Ø Calcified sharpy’s fiber. Ø Calcified vessels.  Periodontal Ligament Functions n Physical function. n Formative and remodeling function. n Nutritional function. n Sensory function.  Physical function n Attachment of the teeth to the bone. n Provides soft tissue casing(to protect vessels and nerves from injury by mechanical forces). n Resistance to the impact of occlusal forces(shock absorption). n Transmission of occlusal forces to the bone. shock absorption  Formative and Remodeling Function n Cells of the PDL participate in the formation and resorption of cementum and bone, which occur during physiologic tooth movement and during the repair of injuries. Nutritional and sensory function n PDL blood vessels provides nutrition to the cementum, bone and gingiva n PDL nerve transmitting tactile, pressure, and pain sensations n Nerve bundles pass into the periodontal ligament from the periapical area and follow the course of the blood vessels. Thank you Dr. Aljoharah AL-Sinaidi