Alveolar Bone Structure and Periodontal Defects

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Questions and Answers

What characterizes positive architecture in osseous surgery?

Radicular bone is at the same height as interdental bone

Interdental bone is higher than radicular bone

Radicular bone is apical to the interdental bone (correct)

Interdental bone is more apical than radicular bone

Which type of bone architecture indicates that the interdental bone is more apical than the radicular bone?

Positive architecture

Negative architecture (correct)

Flat architecture

Compensatory architecture

Which method is considered the most reliable for determining the true architecture of bony defects?

Radiographs

Clinical examination with visual inspection

Surgical exposure during flap operations (correct)

Transgingival probing

What type of bone loss is typically not amenable to regenerative periodontal surgery?

Horizontal bone loss (A) Signup and view all the answers

In terms of periodontal disease, which of the following statements is true regarding bone loss patterns?

The type of bone loss can differ in various areas within the same patient (A) Signup and view all the answers

What is the most common pattern of bone loss associated with periodontal disease?

Horizontal bone loss (D) Signup and view all the answers

Which type of defect is characterized by one wall present?

One wall or hemiseptal defect (A) Signup and view all the answers

What best describes osseous craters in periodontal disease?

Concavities confined to facial and lingual walls (C) Signup and view all the answers

What is a defining characteristic of reversed architecture defects?

Loss of facial and lingual plates without radicular bone loss (B) Signup and view all the answers

What condition is most often associated with the development of furcation involvement?

Bacterial plaque accumulation (C) Signup and view all the answers

Bulbous bony contours are primarily caused by which of the following?

Adaptation to function or exostoses (A) Signup and view all the answers

Which bone loss pattern is associated with infrabony pockets?

Angular defects (B) Signup and view all the answers

How far from the bacterial plaque can bone loss be induced according to waerhaugs measurements?

1.5 to 2.5mm (D) Signup and view all the answers

What is the primary function of osteoblasts in the context of bone health?

To synthesize the bone matrix (C) Signup and view all the answers

Which factor is NOT associated with determining alveolar housing?

Salivary flow rate (A) Signup and view all the answers

What happens to the height of alveolar bone in a healthy state?

It is maintained at the CEJ (A) Signup and view all the answers

Which cell type increases as a result of chronic gingival inflammation and contributes to bone destruction?

Osteoclasts (D) Signup and view all the answers

What is a common characteristic of osseous defects formed in periodontal disease?

They are caused by the destruction of alveolar bone (B) Signup and view all the answers

Which transition is associated with the progression from gingivitis to periodontitis?

Changes in bacterial plaque composition (D) Signup and view all the answers

What can cause bone destruction in periodontal disease aside from inflammation?

Trauma from occlusion (C) Signup and view all the answers

Which of the following statements about bone height in relation to CEJ is correct?

Bone height runs parallel to the CEJ at a constant distance (C) Signup and view all the answers

Study Notes

Alveolar Bone Structure and Loss

Alveolar bone surrounds and supports teeth, with facial and lingual cortical plates enclosing cancellous bone.
Alveolar crest margins run parallel to the cementoenamel junction (CEJ) at a consistent 1-2mm distance.
Normal alveolar bone morphology is scalloped with a knife-edge appearance.
Tooth form, embrasure width, CEJ position, and tooth arch position affect alveolar bone housing.

Introduction to Osseous Defects

Osseous defects in periodontal disease result from alveolar bone destruction.
Normal alveolar bone height is maintained at the CEJ by a balance between osteoblast formation and osteoclast resorption.
This balance is influenced by local and systemic factors.

Mechanisms of Bone Formation and Destruction

Osteoblasts synthesize bone matrix, which calcifies.
Periodontal disease-related bone destruction is caused by local and systemic factors.

Local Factors in Bone Destruction

Chronic gingival inflammation is the most common cause of bone destruction in periodontal disease.
Trauma from occlusion can cause bone destruction, even in the absence of inflammation.
A combination of both chronic inflammation and occlusal trauma can also be a causative factor.

Role of Chronic Gingival Inflammation

Chronic gingival inflammation is the primary cause of periodontal bone loss.
Transition from gingivitis to periodontitis involves changes in bacterial plaque composition or host resistance.
Pathogenic bacteria and inflammatory cells within the lesion contribute to its destructive and progressive nature, evidenced by a transition from T-lymphocytes to B-lymphocytes.

Pathways of Inflammation Spread

Inflammation spreads interproximally and facially/lingually into periodontal tissue.

Changes in Bone Due to Inflammation

Gingival inflammation leads to changes in bone marrow spaces, including leukocyte presence and fluid exudates.
Proliferating fibroblasts and blood vessels appear in response to inflammation.
Osteoclast and mononuclear cell increases occur.
Bone trabeculae thin, and marrow spaces enlarge.
Bone height decreases as a result of the above.

Bone Loss from Traumatic Occlusion

Trauma from occlusion is another cause of bone destruction in periodontal disease.
This can occur independently of or in conjunction with inflammation.

Bone Destruction from Systemic Factors

Immune deficiencies, osteoporosis, and smoking are systemic factors contributing to bone destruction.
Generalized skeletal disturbances like hyperparathyroidism, leukemia, and histocytosis X can also cause periodontal bone loss.

Radius of Action

Locally produced bone resorption factors exert their effect primarily in close proximity to the bone surface (1.5-2.5mm).
Bacterial plaque within this area primarily causes bone loss.

Bone Destruction Patterns in Periodontal Disease

Horizontal bone loss, vertical/angular defects, osseous craters, bulbous bony contours, reversed architecture, ledges, and furcation involvement are common.

Horizontal Bone Loss

Horizontal bone loss is the most common pattern of bone loss in periodontal disease.
The bone height reduces, but margins remain perpendicular to the tooth surface.
It is associated with suprabony pockets.

Vertical/Angular Defects

Vertical defects create troughs in the bone along the root.
Angular defects are accompanied by infrabony pockets.
Angular defects are classified by the number of osseous walls. (one, two, or three walled).

Osseous Craters

Osseous craters are concavities in the interdental bone crest, bounded by facial and lingual walls.
They commonly appear on mandibular bone (higher proportion) as compared to maxillary.

Reversed Architecture

Reversed architecture defects result from loss of interdental bone, including facial and lingual plates, without accompanying loss of radicular bone.
Maxillary location is more common.

Bulbous Bony Contours

Bulbous bony contours are enlargements from exostoses, adaptation to function, or buttressing bone formation.
They are more common in the maxilla than the mandible.

Ledges

Ledges are plateau-like margins of bone, resulting from resorption of thickened bony plates.

Furcation Involvement

Furcation involvement occurs when periodontal disease invades the bifurcations or trifurcations of multirooted teeth.
Mandibular molars are the most affected.

Types of Osseous Surgery

Osseous surgery types are classified based on the relative positioning of interdental and radicular bone (positive, negative, or flat).

Diagnosis of Osseous Defects

Clinical examination (transgingival probing), radiographs (not precise for bone wall evaluation), and surgical exposure (precise bone evaluation) are methods for diagnosing osseous defects.

Conclusion

Periodontal disease bone loss patterns vary, even in the same person, and can differ between areas.
Regenerative periodontal surgery, using bone grafts, bioactive molecules, and membranes, can treat vertical bone loss.
Horizontal bone loss and osseous craters typically require flap surgery combined with osseous surgery.

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Description

This quiz explores the structure of alveolar bone and the dynamics of its loss in periodontal disease. Learn about the factors influencing bone morphology, the balance between bone formation and destruction, and the impact of local conditions on osseous defects.