1. Bone Loss and Patterns of Bone Destruction
黃仁勇 DDS PhD
國防醫學院牙醫學系
三軍總醫院牙周病科

2. Bone Loss and Patterns of Bone Destruction
Periodontitis: infectious disease of the gingiva destruction of bone tooth loss

3. Bone Loss and Patterns of Bone Destruction
Density and height of bone inflammation local factors trauma from occlusion systemic disorders
equilibrium of bone resorption and formation

4. Bone Loss and Patterns of Bone Destruction
bone level: experience of past inflammation
pocket change: present inflammatory condition
both are not necessarily correlated

5. Bone destruction caused by extension of gingival inflammation
Chronic inflammation:
gingiva bone, PDL
gingivitis periodontitis ?

6. Bone destruction caused by extension of gingival inflammation
*bacterial composition in plaque:
motile, spirochetes increased
cocoid, straight rod decreased
*cell composition in infiltrated connective
tissue (ICT):
fibroblast, lymphocyte predominant
plasma cell, blast cell predominant
*immune reaction:
T-cell predominant B-cell predominant

7. Bone destruction caused by extension of gingival inflammation
Extension of inflammation: 1. pathogenic potential of plaque 2. resistance of host: *immunologic activity
*tissue-related mechanisms: fibrosis of gingiva width of attached gingiva reactive fibrosis & osteogenesis

8. Bone destruction caused by extension of gingival inflammation
Histopathology: gingival inflammation extends along the collagen fibers and follows the course of blood vessels through the loosely arranged tissue around them into the alveolar bone

9. Bone destruction caused by extension of gingival inflammation

10. Bone destruction caused by extension of gingival inflammation
Histopathology: pathways (interproximal)
*gingiva trans-septal fibers bone crest marrow PDL angle of crest
*gingiva PDL

11. Bone destruction caused by extension of gingival inflammation
Histopathology: pathways (facial & lingual)
*gingiva outer periosteum bone *gingiva PDL

12. Bone destruction caused by extension of gingival inflammation

13. Bone destruction caused by extension of gingival inflammation
Histopathology: there is a continuous tendency to recreate trans-septal fibers across the crest of the interdental septum farther along the root as the bone destruction progresses

14. Bone destruction caused by extension of gingival inflammation

15. Bone destruction caused by extension of gingival inflammation
Histopathology: *marrow: leukocyte, fluid exudates, new blood vessel, proliferating fibroblast, enlarged marrow space *bone: multinuclear osteoclasts, mononuclear phagocytes, Howship lacunae on the bone surface, thinning trabeculae

16. Bone destruction caused by extension of gingival inflammation

17. Bone destruction caused by extension of gingival inflammation

18. Bone destruction caused by extension of gingival inflammation
Histopathology: *not bone necrosis *tissue necrosis and pus in the soft tissue wall of periodontal pocket *osteoclast: remove mineral portion mononuclear cell: degrade organic matrix

19. Bone destruction caused by extension of gingival inflammation
Histopathology: *the amount of inflammatory infiltrate
bone loss No. of osteoclasts *the distance from the apical border of the inflammatory infiltrate to the alveolar crest No. of osteoclasts total No. of osteoclasts on the alveolar crest

20. Bone destruction caused by extension of gingival inflammation
Radius: (Page & Schroeder)
bacterial effectiveness within mm
*interproximal angular bony defect occurred only if interproximal space > 2.5mm

21. Bone destruction caused by extension of gingival inflammation
Rate of bone loss: (Loe in Sri Lankan)
*untreated periodontitis: 0.2mm(facial), 0.3mm(interproximal) bone loss per year *8% rapid loss of att. (0.1-1mm per year) *81% moderate loss of att. ( mm per year)
*11% minimal or no loss of att. ( mm per year)

22. Bone destruction caused by extension of gingival inflammation
Periods of destruction: episodic, intermittent burst related to: *acute inflammatory reaction *T-lymphocyte to B-lymphocyte & plasma cell *loose, unattached, motile, Gram(-), anaerobic flora *followed by advanced local host defense

23. Bone destruction caused by extension of gingival inflammation
Mechanisms of bone destruction: plaque products
gingival cells mediators bone progenitor cells osteoblasts osteoclasts

24. Bone destruction caused by extension of gingival inflammation
Mechanisms: inflammatory cells prostaglandins (PGE2) prostaglandin precursors (IL-1α,IL-1β,TNF-α) bone resorption

25. Bone destruction caused by extension of gingival inflammation
Bone formation in periodontal disease *response of alveolar bone for inflammation: bone resorption and bone formation
*bone formation: adjacent to sites of active bone resorption & along trabecular surface at a distance from the inflammation (buttressing bone formation)

26. Bone destruction caused by extension of gingival inflammation
Bone formation in periodontal disease *bone loss: bone resorption > bone formation
*the basic aim of periodontal therapy is the elimination of inflammation to remove the stimulus for bone resorption

27. Bone destruction caused by trauma from occlusion
TFO without inflammation *funnel-shaped widening of the crestal portion of PDL *bone resorption cause angular shape defect (cushioning effect) *increased tooth mobility *reversible
TFO with inflammation *speed up the bone loss caused by inflammation

28. Bone destruction caused by trauma from occlusion

29. Bone destruction caused by systemic disorders
Osteoporosis: *menopause women *loss of bone mineral content and structural bone changes *share some risk factors with periodontitis: aging, smoking, disease, medications that interfere with healing
Generalized skeletal disturbances: *hyperparathyroidism, leukemia, Langerhans cell histocytosis *probably totally unrelated to the usual periodontal problem

30. Bone destruction caused by systemic disorders
hyperparathyroidism

31. Factors determining bone morphology in periodontal disease
Normal variations in alveolar bone
Exostoses
Trauma from occlusion
Buttressing bone formation
Food impaction
Aggressive periodontitis

32. Factors determining bone morphology in periodontal disease
Normal variations in alveolar bone *the width, thickness & crestal angulation of interdental septa *the thickness of the facial and lingual alveolar process *the presence of fenestration & dehiscence *the alignment of the teeth *root and root trunk anatomy *root position within the alveolar process *proximity with another tooth surface

33. Factors determining bone morphology in periodontal disease
Normal variations in alveolar bone

34. Factors determining bone morphology in periodontal disease
Exostoses
*outgrowth of bone of varied size and shape
*palatal exostoses:40%

35. Factors determining bone morphology in periodontal disease

36. Factors determining bone morphology in periodontal disease
Trauma from occlusion
*thickening of cervical marginal bone
*angular bone defect

37. Factors determining bone morphology in periodontal disease
Buttressing bone formation
*central: within the bone
*peripheral: external surface (lipping)

38. Factors determining bone morphology in periodontal disease

39. Factors determining bone morphology in periodontal disease
Food impaction *interdental bone defect *pressure & irritation *complicating factor
Aggressive periodontitis *vertical or angular defect in 1st molar

40. Bone destruction patterns in periodontal disease
Horizontal bone loss
Bone deformities (osseous defects) *vertical, angular defect *osseous crater *bulbous bone contour *reverse architecture *ledge *furcation involvement

41. Bone destruction patterns in periodontal disease
Horizontal bone loss: *bone height reduced *bone margin perpendicular to the tooth surface *interdental septa and facial & lingual plate affected *x-ray: bone margin parallel to CEJ- CEJ

42. Bone destruction patterns in periodontal disease

43. Bone destruction patterns in periodontal disease
Bone deformities (osseous defects) *vertical (angular) bony defects (with infra-bony pockets) 1-wall (hemiseptum) 2-wall 3 wall (intrabony defect): mesial of molars combined: more walls in apical portion

44. Bone destruction patterns in periodontal disease

45. Bone destruction patterns in periodontal disease

46. Bone destruction patterns in periodontal disease

47. Bone destruction patterns in periodontal disease
*osseous crater
--concavity in the crest of interdental bone
--within the facial and lingual wall
--35.2% of all defects; 62% of man. defects
--posterior: anterior=2:1
--causes: difficult to remove plaque flat or concave interdental septum in man molars vascular patterns from the gingiva to the center of the crest

48. Bone destruction patterns in periodontal disease

49. Bone destruction patterns in periodontal disease
*bulbous bone contours: --bony enlargement --maxilla --cause: exostoses buttressing bone formation adaptation to function

50. Bone destruction patterns in periodontal disease

51. Bone destruction patterns in periodontal disease
*reverse architecture: --reversing the normal architecture --maxilla --cause: interdental bone loss, radicular bone exist

52. Bone destruction patterns in periodontal disease

53. Bone destruction patterns in periodontal disease
*ledge: --plateau-like bone margin --cause: resorption of thickened bone plate

54. Bone destruction patterns in periodontal disease

55. Bone destruction patterns in periodontal disease
*furcation involvement:
--invasion of the bifurcation and
trifurcation of multi-rooted teeth by
periodontal disease
--most in man. 1st molars; least in max. premolars

56. Bone destruction patterns in periodontal disease
*furcation involvement:
--classification:1958 Glickman(horizontal)
Grade I incipient II cul-de-sac III through-and through IV III & gingival recession

57. Bone destruction patterns in periodontal disease
*furcation involvement: --classification: 1938 Lindhe (horizontal) Grade I initial, <1/3 B-L width II >1/3 B-L width III through-and-through & gingival recession

58. Bone destruction patterns in periodontal disease
*furcation involvement:
--classification:1975 Hamp et al
(horizontal)
Grade I <3mm II >3mm III through-and through

59. Bone destruction patterns in periodontal disease
*furcation involvement:
--classification: 1984 Tarnow & Fletcher
(vertical)
Grade A mm B mm C >7mm

60. Bone destruction patterns in periodontal disease
*furcation involvement:
--causes: plaque TFO (?): contributing factor enamel projection: 13% proximity of furcation to CEJ:
75% in F.I accessory pulpal canals: % in max. 1st molars; 32% in man. 1st molars % in max. 2nd molars; 24% in man. 2nd molars

61. Bone destruction patterns in periodontal disease
*furcation involvement: --diagnosis: probing (horizontal and vertical) radiography

62. Bone destruction patterns in periodontal disease

63. Bone destruction patterns in periodontal disease

64. Bone destruction patterns in periodontal disease
Furcation involvement & enamel projection