2024 Macroscopic Anatomy of Periodontium PDF

ANATOMY OF THE PERIODONTIUM DR P MOSHAPO DEPARTMENT OF ORAL MEDICINE AND PERIODONTOLOGY 2024 Periodontal disease Anatomy of tooth/ supporting structures Term ‘periodontal’ ‘Peri ‘around / ‘odont tooth Tissues of periodontium Anatomically/functionally-...

ANATOMY OF THE PERIODONTIUM DR P MOSHAPO DEPARTMENT OF ORAL MEDICINE AND PERIODONTOLOGY 2024 Periodontal disease Anatomy of tooth/ supporting structures Term ‘periodontal’ ‘Peri ‘around / ‘odont tooth Tissues of periodontium Anatomically/functionally- healthy, viable supporting structure Attaches teeth – bone(jaws) Masticatory function Lateral/horizontal movements Accommodate these movements TISSUES OF PERIODONTIUM  ORAL MUCOSA o MOIST MUCOUS MEMBRANE LINES INSIDE OF MOUTH  COLLECTIVELY ALL SOFT TISSUES IN MOUTH ORAL MUCOSA MACROSCOPIC ANATOMY  Masticatory mucosa  Specialized mucosa  Lining mucosa MASTICATOR Y MUCOSA  Gingiva / hard palate  25% of total oral mucosa  unmovable  Attached to Underlying bone  Keratinised/parakeratinised  Keratin- mechanical toughness of superficial layers  Primary mucosa in contact with food during mastication  Function - Frictional forces of food SPECIALISED MUCOSA  Dorsum  15% of total oral mucosa  Has many Taste buds/many papillae  Function - Sensation of taste LINING MUCOSA  Lips, buccal mucosa, floor of mouth, ventral surface of tongue, uvula soft palate, alveolar mucosa  60% of total oral mucosa  No function in mastication  Not attached  Movable, soft , pliable  Non keratinised, slender c/tissue stretch /recoil  Rich elastic fibre plexus permits wide movements speech / mastication  GINGIVA  Oral cavity –visible  Covered – epithelium  Attach to tooth at/above CEJ  Functions against mechanical and microbial damage  Morphologically (Macroscopic) divided: o Free/Marginal gingiva o Attached gingiva o Interdental papillae  Microscopically:  Gingival connective tissue, crevicular fluid  Oral epithelium, junctional epithelium, sulcular epithelium GINGIVA  Size  Colour  Texture  Consistency  Sulcus depth  GINGIVA CONSISTS OF 3 PARTS:  FREE (MARGINAL)  ATTACHED  INTERDENTAL PAPILLA  Free marginal groove- depression on gingiva/ v shaped groove FREE GINGIVA Not attached Surrounds tooth 0.5 – 2mm Soft wall of sulcus ATTACHED GINGIVA Apical to / coronal to Firm resilient tissue 1-9mm Ind –ind, area – area, tooth – tooth Bound to bone INTERDENTAL PAPILLAE Embrasures between teeth Commonly stippled Triangular (ant) - flatter(pos) COL area Depression gingiva FUNCTIONS OF GINGIVA  Attaches dental hard tissues to oral mucosa  Protects Periodontal tissues from invasion by bacteria  FIBRE BUNDLES 5 MAIN FIBRE , 6 MINOR FIBRE BUNDLES 5 MAIN FIBRE BUNDLES  Dentogingival – from cementum into free & attached gingiva –provides support  Alveologingival – from periosteum into attached gingiva provides attachment  Dento periosteal – from cementum to crest of bone plays role in anchorage  Circular group- it circles tooth( from coronal to crest)- provides support  Transeptal group cementum of one tooth to cementum of adjoining tooth- maintains relationships PERIODONTAL LIGAMENT  PERIODONTAL LIGAMENT  Is made up of Specialized connective tissue fibres that attaches tooth to bone  Has bands of collagen fibres, loose connective tissue, blood vessels, lymphatic vessels and nerves  Has an Hourglass shape  Copious Blood supply  Rich Nerve supply- nutrition for cells  2 types of nerves- SAN/IAN  Sensory & autonomic  It is approx. 0.2 mm in width  Width varies in individuals  Width would depend on Age / location of tooth / degree of stress to which an individual is subjected to  Shows a progressive decrease with age  There is a 0.4 – 1.5mm space between root surface and bone  NB: PDL always in a state of remodeling  Part of periodontium responsible for attachment of teeth to alveolar bone by way of cementum  PERIODONTAL LIGAMENT FUNCTIONS  Tooth suspended in alveolus by PDL - Allows for limited movement of individual teeth  tooth anchorage – tooth to bone/ shock absorber/Transmits tension  Suspensory cushion between root surface and bone- cushions teeth against excessive occlusal forces- thus protecting blood vessels and nerves at apex  fibrous tissue formation and maintenance  calcified tissue development and maintenance  transport of nutrients and metabolites  sensory function: touch,percussion,pain and proprioception sensors provide proprioception output – detects pressures on tooth PERIODONTAL LIGAMENT FIBRE BUNDLES FUNCTIONS OF FIBRE BUNDLES  Attach tooth to bone  Can transmit occlusal forces to bone  Can counteract and oppose occlusal forces  Protect vessels and nerves against damage  Alveolar crestal group – from cementum, just apical to crest of alveolar bone  Horizontal fibre bundles – attaches the most coronal 10-15% of the root surface with alveolar bone  Oblique group – covers about 80-85% of the cemental surface  Apical fibre group – from the apex of a root to the alveolar bone; both apical and lateral to the apex  Interradicular fibre bundles – at teeth with more than one root – it spreads apically to the bone from the furcation  All fibres resists tilting, intrusive,extrusive or rotational forces ROOT CEMENTUM  CEMENTUM  Part of tooth and periodontium  Covers root surface  Similar to bone but less resorbed than bone. The reasons are unclear  Regenerate / resorb - Orthodontic treatment  Cementum moves with movement of the tooth  Calcified /mineralized structure  Varies in thickness at different levels of root of tooth  Contains Sharpey’s fibres – mineralized collagen fibres- anchors tendons  Attaches fibre bundles of the PDL to the root  Is avascular  Acellular/primary – Entire root surface/ First to form  Cellular/secondary – after tooth eruption  FUNCTIONS Different functions attributed to different types of cementum STILL FUNCTIONS AS A SINGLE UNIT  Helps with the anchorage of the tooth to bone– principal fibres of PDL  Maintains width of PDL space  Protects and strengthens roots/Repairs root fractures – deposits new cementum  Maintains occlusal relationships –maintains a balance between attrition and eruption  Supplies a seal for the dentinal tubuli (little tubes in dentin – comm pulp)  Always forms when root surface is in contact with PDL fibers – no connective tissue attachment / no cementum  No resorption under masticatory or orthodontic forces- maintains tooth integrity /achieves orthodontic requirements ALVEOLAR BONE ALVEOLAR BONE /ALVEOLAR PROCESS ALVEOLAR PROCESS  AP – Thickened ridge of bone contains tooth sockets on bones that contain teeth  Is the Support system of the teeth  It is a Specialised structure –designed to accommodate teeth  Thick and dense compared to other types of bone  Reason: provides adequate support for teeth  Includes sockets – designed to accommodate roots and lower part of teeth  Sockets separated from each other by an interdental septum  Has many perforations for small vessels and nerves which supply the periodontium.  is visible as the lamina dura on radiograph  The tooth-socket is called the “alveolus”  Each tooth has its own alveolus  ALVEOLAR PROCESS (AP) The alveolar process consists of three components:  Alveolus or cribriform plate  Compact bone – forms the facial and lingual cortical plates  Trabecular (or marrow bone) between the cortical plates and the alveoli  ALVEOLAR BONE  RADICULAR BONE  INTERPROXIMAL BONE  INTERADICULAR BONE  CRESTAL BONE  ALVEOLAR PROCESS (AP)  functions as a unit  Is tooth dependent  undergoes slow resorption when teeth are lost  Alveolar crest follows the outline of CEJ of the teeth in a healthy situation  The margin of the crest lies 2- 3mm apical to the CEJ ALVEOLAR BONE  Constant state of remodelling  Includes: physiological tooth movement (drifting,migration.mastication) bone deposition / bone resorption (changes size,shape,proportion, relationship of bone with adjacent structures  Compact bone forms cortical plates – facial/lingual  Bone dependant on angulation /arrangement of teeth  Less trabecular bone in mandible than maxilla  REFERENCES 1. Perry, Beemsterboer, Taggart(2014) Periodontology for the Dental Hygienist 4th Edition. Elsevier 2. Wilkins EM (2017). Clinical practice of the Dental Hygienist 12th Edition. Lippincott Williams & Wilkins 3. Newman MG, Takei HH, Klokkevold PR Carranza FA (2015) Periodontology 12thEdition.Saunders Elsevier THANK YOU FOR YOUR ATTENTION