The document discusses bone loss and patterns of bone destruction in the context of periodontitis, emphasizing that bone destruction leads to tooth loss and is influenced by various factors including inflammation, trauma, and systemic disorders. It details the histopathology of bone loss, different types of bone defects, and classifications of furcation involvement, providing insight into how periodontal disease affects bone morphology. Various patterns of bone destruction, such as horizontal and vertical bone loss, are also described, outlining their implications for periodontal health.

1. BONE LOSS AND
PATTERNS OF BONE
DESTRUCTION
DR DEEPTHI CHERIAN
DEPT OF PERIODONTICS

2. INTRODUCTION
 Although periodontitis is an infectious disease of the
gingival tissue,changes that occur in bone are crucial
because the destruction of bone is responsible for tooth
loss.
 Height and density of the alveolar bone are normally
maintained by an equilibrium, regulated by local and
systemic influences ,between bone formation and
resorption.
 Resorption>formation-bone height and density reduced.
 Degree of bone loss not related with pocket depth or
ulceration on pocket wall or presence or absence of pus.

3. CAUSES OF BONE DESTRUCTION
 Bone destruction caused by the extension of gingival
inflammation.
 Bone destruction caused by trauma from occlusion
 Bone destruction caused by systemic disorder

4. BONE DESTRUCTION CAUSED BY GINGIVAL
INFLAMMATION
 Most common cause-Extension of inflammation from
the marginal ginigiva into supporting periodontal
tissues.

5. Histopathology
• Gingival inflammation
extends
|
• Collagen fibre
|
• Follows course of blood
vessel through loosely
arranged tissues around
them
|
• to alveolar bone.

6. Interproximally:
1) Gingiva -> bone
2) Bone -> PDL
3) Gingiva -> PDL
Facially & lingually
4) Gingiva -> outer
periosteum
5) Periosteum -> bone
6) Gingiva -> PDL

7.  RADIUS OF ACTION

8. BONE DESTRUCTION CAUSED BY
TRAUMA FROM OCCLUSION
 Periodontal response to the external force.
 TFO can occur in presence or absence of
inflammation.
 Absence -> osteoclasts

9.  When combined with inflammation,
 i.e. ZONE OF CO-DESTRUCTION,
 Aggrevate bone destruction caused by
inflammion
 Result in Bizzare pattern

10. BONE DESTRUCTION
CAUSED BY SYSTEMIC DISORDERS -
 Possible relationship between periodontal bone
loss and systemic disorders.
 OSTEOPOROSIS : loss of bone mineral content
and structural bone changes. Risk factors-
aging,smoking,etc
 •OSTEOPENIA : tooth mobility and tooth loss
 •Hyperparathyroidism, leukopenia

11. FACTORS DETERMINING BONE
MORPHOLOGY IN PERIODONTAL DISEASE-
 1)Normal variation of alveolar bone :
 a)thickness,width,crestal angulation of
interdental septa
 b)thickness of facial & lingual plates
 c)presence of fenestrations & dehiscences
 d)allignement of teeth
 e)root anatomy and position

12. Exostoses :
 a)overgrowth of bone
 b)they can occur as small or large nodules,
sharp ridges , spike-like projections.

13. TFO :
 a)thickening of cervical margin of alveolar
bone.
 b)angular defects or buttressing bone.

14. BUTTRESSING BONE FORMATION - attempt to
buttress the bone subjected to resorption.
 Central and peripheral buttressing bone formation.
 e)results in bulbous bone contours(lipping).

15. FOOD IMPACTION :
 a)interdental bone defects occur when there is
abnormal or absence of proximal contact.
 b)food impaction here , results in inverted bone
architecture.

AGGRESSIVE PERIODONTITIS :
 vertical or angular bone defects.
 Arc shaped

16. BONE LOSS PATTERN
1. Horizontal
2. Vertical or angular
defects
3. Osseous craters
4. Bulbous bone contours
5. Reverse architecture
6. Ledges
7. Furcation involvement

17. HORIZONTAL BONE LOSS
 a)most common pattern
 b)bone height reduced, but margin remains
perpendicular to tooth surface.

18. VERTICAL BONE LOSS
a)angular defects , occur in an oblique direction
leads to hollowed-out trough in the bone alongside
root.
b)Depending on number of walls present , angular
defects were classified by Goldman and Cohen
(1958) as,
 (i)Three osseous walls
 (ii)Two osseous walls
 (iii)One osseous wall
 (iiii)Combination

22. OSSEOUS CRATERS
 a)concavities in the crest of interdental bone confined
within faciolingal walls.
 b)Reasons :
(i)plaque accumulation and difficulty to clean.
(ii)normal concavity in lower molars
(iii)vascular patterns crest, a pathway for
inflammation

23. BULBOUS BONY CONTOURS :
 a)bony enlargement
 b)an adaptation to Exostoses
 c)adaptation to function or buttressing bone
formation.

24. REVERSED ARCHITECTURE :
 produced by loss of interdental bone, facial and lingual
plates without concomitant loss of radicular bone.

25. LEDGES:
(a)plateau-like bony margins
(b)caused by resorption of thickened bony plates

26. FURCATION INVOLVEMENT :
 Invasion of bifurcation or trifurcation of
multirooted teeth by periodontal disease.
Classification-
 (i)Grade 1 : incipient bone loss
 (ii)Grade 2 : partial bone loss
 (iii)Grade 3 : total bone loss with through and
through opening of furcation
 (iiii)Grade 4 : similar to grade 3,with gingival
recession exposing the furcation to view.

29. 1) Patterns of bone destruction
2) Reverse architecture
3) Furcation involvement