anatomyofperiodontium periodon-180923181101.pdf
- 2. Dr. Enas Elgendy Ass. Professor of Oral Medicine, Periodontology& Oral Diagnosis Faculty of Dentistry Kafrelsheikh University
- 3. The term Periodontium arises from the Greek word peri meaning around and odont meaning tooth, thus it can be simply defined as the “tissues investing and supporting the teeth”. The various diseases of the periodontium are collectively termed as Periodontal diseases. Their treatment is referred to as Periodontal therapy. The clinical science that deals with the periodontium in health and disease is called Periodontology. The branch of dentistry concerned with prevention and treatment of periodontal disease is termed Periodontics or Periodontia.
- 6. T he tissues that surround and support the teeth are known as the periodontium. It includes: 1- The gingiva. 2- The periodontal ligament. 3- The root cementum. 4- The alveolar bone.
- 7. The gingiva is that part of the oral mucosa which surrounds the tooth and covers the alveolar ridge. It forms a connection with the tooth and protects the underlying tissues of the periodontium (bone & periodontal ligament) from the oral environment. AM, alveolar mucosa G, gingiva MGJ, mucogingival junction
- 8. Pink in color Firm and resilient (resist deformity) in consistency and not bleeding on probing Knife-edged and scalloped to conform to the contour of the teeth. The surface of the gingiva exhibits an orange peel-like appearance referred to as stippling
- 9. The periodontium is consists of ………………, …………….., ……………., ……………. Healthy Gingiva is ………………, …………….., …………………, ……………..
- 10. 1. Masticatory mucosa: Is a tissue that is firmly attached to the underlying bone and covered with parakeratinized or keratinized epithelium. The gingiva and the tissue covering the hard palate are examples. 2. Lining mucosa: Loosely attached to their underlying structures and covered with non-keratinized epithelium. Lips, cheeks, floor of the mouth. 3. Specialized mucosa: Covers the dorsal surface of the tongue.
- 11. The gingiva consists of which type of mucosa? 1. Alveolar mucosa 2. Masticatory mucosa 3. Specialized mucosa 4. Non of the above
- 12. The marginal (free) gingiva The interdental gingiva The attached gingiva
- 13. The marginal gingiva forms a cuff 1-2 mm wide around the neck of the tooth and it is the external wall of the gingival crevice. The marginal gingiva can be separated from the tooth by a blunt probe. The surface of marginal gingiva is smooth in contrast to the attached gingiva which is stippled. The marginal gingiva is demarcated from the attached gingiva by a shallow, v-shaped or an indentation called the free gingival groove.
- 14. It is defined as the space or shallow crevice between the tooth and the free gingiva. It is V-shaped and barely permits the entrance of a periodontal probe. Under normal or ideal conditions it is about 2 to 3 mm. The gingival sulcus is probing depth of a clinically-normal gingival. It provides good resistance to mechanical forces.
- 15. It is an inflammatory exudate that carries polymorphonuclear leukocytes and other antimicrobial substances into the gingival crevice (sulcus). If filter paper strip is inserted into the gingival crevice it will absorb gingival fluid already in the crevice and also stimulate the outward flow of the gingival fluid. The increase in gingival fluid flow is also associated with inflammation.
- 16. The gingival fluid forms part of the defense mechanism of the dentogingival junction. In summary, it performs the following functions: It washes the crevice, carrying out shed epithelial cells, leukocytes and bacteria. It contains antimicrobial components e.g. lysosome, antibodies and complement. It carries PMNLs and macrophages which are capable of phagocytosing bacteria.
- 17. Facial papilla Lingual papilla Col region The interdental gingiva occupies the space in the interdental embrasure apical to the contact point. There are three parts of interdental gingiva:
- 18. In anterior teeth, the interdental papilla is pyramidal form while in the molar region, the papillae are flattened in buccolingual direction (tent shape). The shape of the interdental papilla is determined by: 1. the contact relationships between the teeth 2. the width of the proximal tooth surfaces 3. coarse of the CEJ.
- 19. If the contours of interproximal contact are flat, the gingiva will be narrow and short. If the proximal contours are more convex with a small coronally positioned contact area, the interdental gingiva will be broad and high.
- 20. The loss of papilla can lead to cosmetic deformities (so- called “black triangle”), phonetic problems (space allows passage for the air or saliva), and lateral food impaction.
- 21. In teeth with contact surface rather than contact point, the interdental papilla has a col region. The "col" is depression which joins the facial and lingual papilla. The col region is covered by a thin non-keratinized epitheliumwhich is not a powerful barrier against bacterial insult. .
- 22. The interdental region is of special importance (give reasons) The col region is covered by a thin non-keratinized epitheliumwhich is not a powerful barrier against bacterial insult, as it is the site of the most persistent bacterial stagnation. It is the site of initial lesion in gingivitis .
- 23. The shape of the interdental papilla is determined by: 1. the contact relationships between the teeth 2. the width of the proximal tooth surfaces 3. coarse of the CEJ. 4. All of the above
- 24. It extends from the free gingival groove to the mucogingival junction where it meets the alveolar mucosa. The attached gingiva is tightly bound to the underlying alveolar bone. Function of attached gingiva: 1- It provides gingival tissue that can withstand the mechanical forces of mastication, brushing and tension applied on mucosa. 2- Prevent free gingiva from being pulled away from the tooth when tension is applied to the alveolar mucosa.
- 25. The surface of the attached gingiva is stippled like orange peel. The width of the attached gingiva can vary from zero to 9 mm. Attached gingiva is greatest in incisor region (3.5-4.5 in maxilla, 3.3-3.9 in mandible). L east in canine and premolar area (1.9 mm in maxilla, 1.8
- 26. The alveolar mucosa is separated from the periostium by a loose, highly vascular connective tissue. Thus the alveolar mucosa is relatively loose and mobile tissue, deep red, in marked contrast to the pale pink attached gingiva.
- 27. (1) mucogingival junction, (2) interdental papilla, (3) free gingiva groove, (4) attached gingiva, (5) alveolar mucosa, (6) gingival margin (1) Enamel, (2) gingival margin, (3) small gingival sulcus, (4) free gingival groove, (5) alveolar bone, (6) cemento- enamel junction, (7) cementum, (8) periodontal ligament
- 28. The salivary flow, saliva contains lysozyme and IgA. Cell turnover and surface shedding (desquamation). Anatomical epithelial seal. The gingival fluid, it contains several defensive components.
- 30. Complete: The marginal gingiva is demarcated from the attached gingiva by ………………….., and the attached gingiva is demarcated from the alveolar mucosa by ……………… The Gingival Defense Mechanisms Include ………………….., …………………, …………………, ………………….
- 31. A B C D What are the name of A , B , C and D?
- 32. The understanding of clinical features of periodontium is enhanced by a knowledge of histological component of tissue.
- 33. Gingival epithelium Gingival connective tissue The gingiva is consists of Oral (outer) epithelium Sulcular epithelium Junctional epithelium
- 34. Three zones of gingival epithelium: Oral (outer) epithelium which is keratinized (from the mucogingival junction to the gingival margin). Sulcular epithelium which are non- keratinized (lines the gingival crevice). Junctional epithelium which are non- keratinized (lies at the base of the gingival crevice).
- 35. Keratinized or parakeratinized consist of four layers: 1) Basal or formative cells layers of columnar cells (The deepest cells); it is characterized by active mitosis (stratum basal or stratum grrminativum). 2) Prickle or spinous cell layer of polygonal cells (stratum spinosum). 3) Granular cell layer in which the cells are flatter and contain many particles of keratohyaline (stratum granulosum). 4) Cornified or keratinous cell layer in which cells have become flat, shrunken and keratinized (stratum corneum).
- 36. Gingival epithelial cells are connected to each other by desmosomes. Desmosome consists of two attachment plaque associated with tonofilaments and an intercellular cementing substance formed of polysaccharides. Gingival epithelial cells are also attached to the underlying connective tissue by hemidesmosome (one attachment plaque).
- 37. Gingival epithelial cells are connected to each other by desmosomes. Gingival epithelial cells are also attached to the underlying connective tissue by hemidesmosome
- 38. The boundary between the oral epithelium and the underlying connective tissue has a wavy course. The connective tissue portion which project into the epithelium is called connective tissue papillae and are separated from each other by epithelial ridges (rete pegs). Epithelium/connective tissue interface A, connective tissue. Arrows point at finger-like papillae in papillary layer. B, epithelium. Arrows point at interconnected rete ridges on the epithelium undersurface.
- 40. Three zones of gingival epithelium are ……………, ……………… , ………………………. Gingival epithelial cells are connected to each other by …………………, and to the underlying connective tissue by ……………………
- 41. It lines the gingival sulcus facing the tooth similar to oral epithelium except the 2nd layer (it lacks granular cell layer) It acts as semipermeable membrane allows bacteria to pass into gingiva. Sulcular epithelium GS, gingival sulcus ICS, intercellular spaces PKC, parakeratinized epithelium
- 42. lies at the base of the crevice, it mediate the connection of the gingiva with the tooth. In health the junctional epithelium lies against enamel and extends to the cemento-enamel junction without wavy course at the junction between the epithelium and connective tissue.
- 43. The gingival connective tissue is composed of: 1. Ground substance 2. Gingival fibers 3. Cells 4. Blood vessels 5. Nerves and 6. Lymphatic vessels
- 44. Connective tissue cells and fibers, together with vessels and nerves are embedded in a matrix which is synthesized by fibroblast and it is made up of: Glycoproteins: it is a protein-polysaccharide molecule in which protein component is predominating. Glycoprotein mediates attachment and migration of fibroblasts. Proteoglycans: it is a protein polysaccharide molecule in which polysaccharide component is predominating. glucosaminoglycans are polysaccharides which can bind large amounts of water providing the characteristic resiliency of the gingiva (i.e. resist compressive force). Glucosaminoglycans also facilitate transport of: nutrients, metablic products, cells and cytokines which are chemical massengers that modulate cellular function.
- 45. Complete: Function of Glycoprotein mediates is …………………………… Function of glucosaminoglycan are ……………………………., …………………………………..
- 46. The gingival connective tissue fibers are produced by the fibroblasts and can be divided into: 1. Collagen fibers 2. Reticulin fibers 3. Elastic fibers.
- 47. The arrangement of these fibers exists into five groups: 1- Dentogingival fibers that are attached to cementum and fan out into the gingiva. 2- Alveolo-gingival fibers that arise from the alveolar crest and run coronally into the gingiva. 3- Circular fibers which encircle the tooth. 4- Trans-septal fibers which run from tooth to tooth coronal to the interdental septum of bone. 5- Periosteogingival fibers that attach gingiva to bone.
- 48. Reticulin fibers are numerous in the tissue adjacent to the basement membrane and surrounding the blood vessels. Elastic fibers are only present in association with blood vessels.
- 49. The gingival connective tissue fibers are …………, …………………………,………………….. The collagen fiber of the gingiva is arranged into ……………………,……………….., ……………………………, ………………………., ……..
- 50. The different types of cell present in the connective tissue are: 1. Fibroblasts 2. Mast cells 3. Macrophages 4. Neutrophils 5. Lymphocytes 6. Plasma cells.
- 51. The gingiva has a rich blood supply derived from three sources: 1. periodontal ligament vessels 2. alveolar vessels 3. supraperiosteal vessels, These links in the gingiva to form capillary loops in the connective tissue papilla between epithelial pegs. Gingival blood supply A, vascular plexus adjacent to junctional epithelium B, vascular plexus adjacent to oral epithelium 1, blood supply from periodontal ligament 2, blood supply from alveolar process 3, supraperiosteal blood supply
- 52. Lymphatic drainage starts in connective tissue papillae and drains into regional lymphnodes; from mandibular gingiva into the submandibular and submental lymphonodes from the maxillary gingiva into the deep cervical lymphnodes.
- 53. The nerve supply is derived from branches of: The trigeminal nerve. A number of nerve endings have been identified in the gingival connective tissue as tactile corpuscles and temperature and pain receptors.
- 54. The gingiva blood supply derived from three sources ……….., ………….., ……………. The gingiva lymph supply derived from……………….,………………………… The gingiva nerve supply derived from………….., ………………………………… The function of gingival fluid are …………, …………, ……….. , …………….
- 55. The periodontal ligament is soft, richly vascular and cellular connective tissue which surrounds the roots of the teeth and joins the root cementum with the lamina dura or the alveolar bone proper.
- 56. The Lamina dura is the wall of the tooth socket that surrounds the root of a tooth. The lamina dura is made up of dense cortical bone.
- 58. 1. Supportive function 2. Shock absorbing function 3. Formative function 4. Sensory function 5. Nutritive function
- 59. The ligament consists of: Collagen Fiber Bundles Ground Substance Matrix Cells Vessels Nerves A, arteriole; BB, bundle bone; C, cementum; CC, cementocytes; D, dentin; F, fibroblasts; M, cell rests of Malassez; NV, neurovascular channel; OB, osteoblasts; OC, osteocytes; SF, Sharpeys fibers; V, thin-walled venules.
- 60. Sharpey’s fibers: The fiber bundles are inserted at one end into cementum and at the other end into the socket (connect between cementum and principle fibers of periodontal ligament & between bone and principle fibers of periodontal ligament). Principal periodontal ligament fibers and their insertion: (1) dentin; (2) cementum with Sharpey’s fibers, surface covered by cementoblasts; (3) periodontal ligament space with principal collagen fibers and scattered fibroblasts; (4) alveolar bone with Sharpey’s fibers, surface covered by osteoblasts.
- 61. AB, alveolar bone; C, cementum; D, dentin; M, cell rest of malassez; NV, neurovascular channel; OB, osteoblasts; PDL, periodontal ligament; RL, reversal line; SF, sharpey's fibers. Junction of periodontal ligament and alveolar bone. Oc, osteocytes SF, sharpey's fibers
- 62. The fiber bundles are classified into: 1)Alveolar crest fibers 2)Oblique fibers: 3)Transseptal fibers 4)Horizontal fibers 5)Interradicular fibers: 6)Apical fibers; Principal periodontal ligament fiber groups: (1) alveolar crest fibers; (2) oblique fibers; (3) transseptal fibers; (4) horizontal fibers; (5) interradicular fibers; (6) apical fibers.
- 63. Cells: Fibroblasts Cementoblasts osteoblasts Osteoclasts Epithelial rest of malassez Formative (stem) cells: which are undifferentiated mesencymal cells (stem cell) that differentiate to osteoblast, fibroblast and cementoblast.
- 64. Fibroblasts are the most abundant cell type in the periodontal ligament because of the high turnover of collagen and proteoglycan with periodontal ligament. These cells are actually engaged in protein synthesis (collagenase), they are also responsible for collagen degradation within the ligament. CF, collagen fiber FB, fibroblasts ICC, intracellular collagen in digestive vacuoles
- 65. Cementoblasts on cementum surface and osteoblasts on endosteal and periosteal surfaces of alveolar bone are abundant when active deposition of bone and cementum is taking place.
- 66. Osteoclasts which are derived from blood monocytes appear on bone surface during bone resorption.
- 67. The periodontal ligament ground substance consists of glycoproteins, proteoglycans and glucosaminoglycans (GAGs). GAGs is similar in composition to that of gingival ground substance. They are important in binding water and may thus act as cushion in periodontal ligament to resist forces of mastication.
- 68. The ligament has a rich network of blood vessels from: 1- apical arteries 2- vessels penetrating the alveolar bone. Nerve bundles from the trigeminal nerve follow the blood vessels from the apex and through the alveolar bone to supply the ligament with tactile, pressure and pain receptors.
- 69. The thickness of the ligament varies from about 0.3 to 0.1 mm. It is widest at the coronal part of the socket and narrowest at the apex. When functional stresses are heavy the ligament is thicker and when a tooth is functionless the ligament can become thinner.
- 70. Cementum is the calcified connective tissue which covers the root dentin and into which periodontal ligament fiber bundles are inserted. It is avascular and without innervations.
- 71. The thickness of cementum varies, the coronal third may be only 16-60 microns and this very thin layer of cervical cementum can be easily removed by dental instrumentation leaving very sensitive area exposed. The apical third can be 200 microns or even thicker. It can triple its thickness throughout life.
- 72. Two different types of cementum: 1)Primary cementum or acellular cementum 2)Secondary cementum or cellular cementum The initial layer of cementum is acellular but during rapid cementogenesis, cementoblasts become entrapped in the newly formed cementum and are called cementocytes.
- 73. Three types of relationships involving the cementum may exist at the cementoenamel junction: 1- Cementum overlaps the enamel (60% to 65%). 2- Edge-to-edge butt joint (30%). 3- The cementum and enamel fail to meet (5% to 10%).
- 74. There are two sources of collagen fibers in cementum: 1- The extrinsic fibers (Sharpey’s fibers) which are the embedded portion of the principal fibers of the periodontal ligament, arranged at right angle to the root surface and are synthesized by fibroblasts of the periodontal ligament. 2- The intrinsic fibers which belong to the matrix of cementum forming irregular mesh work and they are synthesized by cementoblasts.
- 75. Unlike bone there is no evidence of cementum remodelling. Cementum resorption may occur as a consequence of faulty orthodontic movement or pressure from tumor. The greatest thickness of cementum is formed at the apex and in the furcation area. Both cortical and cancellous alveolar bone are constantly undergoing remodelling (resorption followed by formation) in response to tooth drifting and changes in functional forces acting on the teeth to compensate for ever-changing positions of teeth.
- 76. The alveolar process is that part of the jaw bone which supports the teeth. It is partly tooth dependent and after tooth extraction some bone resorption follows. Alveolar bone: 1-Alveolar bone proper (lamina dura in radiographs) 2-Trabecular bone 3-Compact bone
- 77. Supporting alveolar bone: cancellous and cortical bone that surrounds the alveolar bone proper.
- 78. Alveoli: The space in the alveolar bone that accommodate the roots of the teeth (tooth socket). The alveolar bone proper is the compact bone, which in radiographs appears as a continuous radioopaque line (white line) around the roots of the teeth is called "lamina dura". It lines the tooth socket and is perforated by numerous Volkmann's canals through which blood vessels, lymphatics, and nerve fibers pass from the alveolar bone to the periodontal ligament. Crestal lamina dura (the alveolar crest) covers the crest of interproximal bone and called which generally parallels the cemento-enamel junction at a distance of 1-2 mm apical to it.
- 79. Interproximal bone (interdental septum): bone located between the roots of adjacent teeth. Interradicular bone: bone located between the roots of multirooted teeth. Radicular bone: alveolar process located on the facial or lingual surfaces of the roots of teeth
- 80. The basic structural units of the cortical bone are the osteons or the Haversian system with longitudinally oriented cylindrical structures built around vascular central canals called Haversian canals. The nutrition of the bone is secured by the blood vessels in the Haversian canals, which are connected with each other by anastomoses running in Volkmann's canals. ECL, external circumferential lamellae HC, Haversian canals HS1, young Haversian system HS2, mature Haversian system IB, interstitial bone P, periosteum VC, Volkman canal
- 81. Three types of cells are found associated with bone: 1- osteoblasts, 2- osteocytes 3- osteoclasts These cells can be transformed from one type to another or whether they are of separate origins. Actively resorbing osteoclasts adhere to the bone surface and produce lacunar pits called Howship's lacunae.
- 82. Fenestration is window- like defect in the bone. Dehiscence denuded areas extend through the marginal bone.
- 84. What are the name of A and B? A B