Bài 5

The height and density of the alveolar bone are normally maintained by an equilibrium, regulated by:

• Local influences, between bone formation and bone resorption.

• Local and systemic influences, between bone formation and bone resorption.

• Systemic influences, between bone formation and bone resorption.

• Saliva.

Bone destruction in periodontal disease is caused by local factors, including:

• Abnormalities in dental anatomy

• Extension of gingival inflammation

• Extension of dental carries.

• Saliva.

The most common cause of bone destruction in periodontal disease is:

• The extension of inflammation

• Trauma from occlusion.

• Dental caries.

• Changes in saliva.

Periodontitis is always preceded by gingivitis,

• But not all gingivitis progresses to periodontitis.

• All gingivitis progresses to periodontitis.

• All gingivitis progresses to bone loss.

• All gingivitis progresses to tooth loss.

After inflammation reaches the bone via extension from the gingiva,

• It spreads into the marrow spaces.

• It cannot spread into the marrow spaces.

• It spreads into the furcation.

• It spreads into the tooth apex.

In the marrow spaces, resorption proceeds from within and causes:

• A thickening of the surrounding bony trabeculae and an enlargement of the marrow spaces.

• A thickening of the periodontal ligament and an enlargement of the marrow spaces.

• A thickening of the periodontal ligament and dental cement.

• A thinning of the surrounding bony trabeculae and an enlargement of the marrow spaces.

The factors involved in bone destruction in periodontal disease are:

• Bacteria and Saliva.

• Host mediated and saliva.

• Host mediated and foods.

• Bacterial and host mediated.

The second cause of periodontal destruction is trauma from occlusion. Trauma from occlusion can produce bone destruction

• In the presence of inflammation.

• In the absence of saliva.

• In the absence of inflammation.

• In the absence or presence of inflammation.

When it is combined with inflammation, trauma from occlusion aggravates the bone destruction caused by the inflammation and results in:

• Bizarre bone patterns.

• Horizontal bone loss.

• Furcation involvement.

• Gingivitis.

The most common pattern of bone loss in periodontal disease is:

• Horizontal bone loss.

• Vertical defects.

• Angular defects.

• Furcation involvement.