Role of osteoclasts in periodontal health and disease

1. Role of Osteoclasts in
Periodontal Health and
Disease
Kamineni Institute of Dental Sciences
Department of Periodontics
By D. Varunsagar, IV BDS

2. INTRODUCTION
• Osteoclasts are large, multinucleated cells that
originate from hematopoietic tissue
• Osteoclasts are resorptive in nature and break
down bone, while osteoblasts lay down bone
matrix

3. INTRODUCTION

4. INTRODUCTION
• Osteoclasts are regulated by several
hormones:
1. PTH (Parathyroid hormone)
2. Calcitonin
3. IL-1
4. IL-6
5. LIF (Leukemia- Inhibiting Factor)

5. Role of Osteoclasts in Periodontal
Health
• Osteoclasts functions in periodontal health:
1. Formative function
2. Remodeling function

6. Formative Function
• Osteoblasts deposit bone and is balanced by
osteoclasts to prevent excess bone formation
• The number of osteoblasts decreases with
age, however no significant change observed
in the number of osteoclasts

7. Formative Function

8. Remodeling Function
• Bone remodeling involves coordination of
osteoblasts and osteoclasts
• Remodeling is the major pathway of:
1. Bony changes in shape
2. Resistance to forces
3. Repair of wounds
4. Calcium and phosphate homeostasis in the
body

9. Remodeling Function
• When osteoclasts are
active rather than
resting, they possess
an elaborately
developed ruffled
border from which
hydrolytic enzymes
are believed to be
secreted

10. Remodeling Function
• The enzymes digest the organic portion of
bone
• Activity and morphology of ruffled border
regulated and modified by PTH (indirectly) and
calcitonin

11. Remodeling Function
• Another mechanism is where creation of an
acidic environment in the bone surface,
heading to the dissolution of mineral
component of bone
• This event produced by different conditions,
including proton pump through the cell
membrane of osteoclast, bone tumors, and
local pressure, translated through secretory
activity of osteoclasts

12. Remodeling Function
• Sequence of Events by Ten Cate:
1. Osteoclast attachment to mineralized surface of
bone
2. Creation of a sealed acidic environment through
action of proton pump, which demineralizes bone
and exposes the organic matrix
3. Degradation of the exposed organic matrix to its
constituent amino acids by the action of released
enzymes, such as acid phosphatase and cathespin
4. Sequestering of mineral ions and amino acids within
the osteoclast

13. Role of Osteoclast in Periodontal
Disease
• Osteoclast function in periodontal disease:
1. Trauma from Occlusion
2. Systemic Disorders

14. Trauma from Occlusion
• Another cause of bone destruction is trauma from
occlusion, which can occur in the absence or
presence of inflammation
• In absence of inflammation changes caused by
trauma from occlusion vary from increased
compression and tension of the periodontal
ligament and increased osteoclasis of alveolar
bone to necrosis of PDL and bone
• Osteoclasts are triggered and resorption of bone
and tooth structure ensues

15. Trauma from Occlusion
• When combined with inflammation, trauma from
occlusion aggravates the bone destruction caused
by the inflammation
• As the advancing inflammatory front approaches
the alveolar bone, osteoclastic bone resorption
commences
• This is a protective mechanism to prevent
bacterial invasion of the bone, but it ultimately
leads to tooth mobility and even tooth loss
• Resorption of alveolar bone occurs simultaneously

16. Systemic Disorders
• Systemic factors regulate the physiologic
equilibrium of bone:
1. Age: As age increases the number of osteoblasts
reduce in number, but osteoclasts don’t have a
significant decrease in number
2. Systemic Diseases: Osteoporosis, Diabetes,
Immunocompromised state inducing diseases
3. Hormones: PTH, Calcitonin, Growth hormone,
corticosteroids impede healing through various
means

17. THE END