46 Questions
What term is used to describe plateau-like bone margins caused by the resorption of thickened bony plates?
Ledges
Which condition is produced by the loss of interdental bone, including the facial and/or lingual plates, without loss of radicular bone?
Negative architecture
What is the most common site for furcation involvement in multirooted teeth?
Mandibular molars
When the level of radicular bone, facial, and lingual plates are equal, what is this condition called?
Equi-architecture
Which grade of furcation involvement indicates total bone loss with a 'through and through' opening of the furcation?
Grade 3
Which of the following options correctly describes normal periodontal architecture?
Positive architecture
What is key to the transition from gingivitis to periodontitis?
Change in plaque composition
Which of the following correctly describes a less common pathway of inflammation spread?
Inflammatory exudate extends directly from gingiva to PDL then to bone.
What is the initial pathway of inflammatory exudate in the common path?
From gingival epithelium to connective tissue
Which of the following is NOT involved in the common path of inflammatory exudate spread?
Gingival sulcus
During the common path of inflammation spread, what occurs after the exudate reaches the alveolar bone?
Penetration to the B.M space
What is the consequence of inflammatory exudate reaching the bone marrow (BM) space?
Thinning of trabeculae
What occurs to the BM space when replaced by leukocytes and exudates?
It enlarges and replaces fatty BM with fibrous BM
How does bone loss occur during the transition from gingivitis to periodontitis?
Intermittently
How does inflammatory exudate reach the PDL in the common path?
Through the outer periosteal surface of bone and loose tissue around blood vessel channels
What is a characteristic outcome of inflammation reaching the PDL?
Horizontal bone loss and supra bony pocket
What role do transseptal fibers have during periodontal bone destruction?
They continuously regenerate across the crest of the interdental septum
What is a characteristic of exostoses?
They are bony outgrowths of varied size and shape.
Which bone feature is associated with angular bone loss?
Increased thickness of facial and lingual alveolar plates.
How does trauma from occlusion affect bone morphology?
It may change the dimension and shape of bone deformities.
What results from peripheral buttressing in bone?
Bulging of bone contour (lipping).
Which factor is directly associated with the destructive pattern in periodontal disease?
Thickness and crestal angulation of interdental septa.
What is a possible outcome of root position in the jaw related to bone variations?
Uneven bone resorption patterns.
What causes bulbous bone contours?
Bony enlargement caused by exostoses
Where are bulbous bone contours more frequently found?
In the maxilla
What characterizes fenestration in periodontal disease?
Isolated areas of root denuded of bone with intact margin
What characterizes dehiscence in periodontal disease?
Loss of bone margin
Which factor related to the morphology of a tooth can lead to fenestration?
Short root trunk
What happens when the distance between teeth decreases?
Thickness of interdental bone decreases
What pattern of alveolar bone destruction is typically seen around the first molars in interdental bone defects?
Vertical or angular
Which of the following factors does NOT contribute to the extension of inflammation to supporting structures in juvenile periodontitis?
Horizontal bone loss
The presence of tissue necrosis and pus in periodontal disease is typically originated from:
The walls of soft tissue pocket
Osteoclasts are primarily involved in which process during bone destruction?
Removing the marginal portion of the bone
Which of the following conditions is associated with bone necrosis?
Necrotizing ulcerative periodontitis
Food impaction in interdental areas is considered:
A complicating factor in bone defects
Which factor is NOT involved in host mediated bone destruction?
Bacteria
Which of the following is a direct action mechanism of bone loss by plaque?
Direct destruction of the bone (non-cellular mechanism)
What coincides with periods of remission in bone loss?
Formation of dense, unattached, non-motile, gram-positive organisms
Which of the following is associated with bursts of destructive activity?
Changes in composition of bacterial plaque to motile gram-negative, anaerobic organisms
Which mediator is released during the indirect action of bone loss by plaque, leading to progenitor cell differentiation into osteoclasts?
Interleukin-1 alpha
Which of the following statements is FALSE regarding the periods of bone destruction and remission?
T-lymphocyte lesions convert to B-lymphocyte-plasma cell infiltrates during periods of remission.
What is the optimum distance from the bone surface for local factors to cause bone resorption?
1.5-2.5 mm
At what rate does bone loss occur per year on facial surfaces in patients with poor oral hygiene?
0.2 mm per year
According to Loe, what is the yearly connective attachment loss (CAL) range for moderate periodontitis?
0.05 - 0.5 mm
Based on Waerhaug's measurement, what distance beyond the bone surface results in no bone resorption effect?
2.5 mm
What percentage of patients experience severe periodontitis with a yearly CAL of 0.1 - 1 mm?
8%
Study Notes
Extension of Inflammation
- The transition from gingivitis to periodontitis occurs when inflammation extends from the marginal gingiva to the supporting structure.
- Bone loss occurs in episodes.
Pathway of Inflammatory Exudate
Interproximal
- The common path involves inflammatory exudate extending from the gingiva to the alveolar bone, destroying transseptal fibers, and reaching the periodontal ligament (PDL) and bone marrow space, leading to horizontal bone loss and supra bony pocket.
- The less common pathway involves inflammatory exudate extending directly from the gingiva to the PDL and then to the bone.
Facial or Lingual
- The common path involves inflammatory exudate extending from the gingival epithelium to the connective tissue, reaching the outer periosteal surface of the bone, and penetrating the bone marrow space, leading to horizontal bone loss and supra bony pocket.
- The less common pathway involves inflammatory exudate extending directly from the gingiva to the PDL and then to the bone.
Clinical Importance of Fibers
- Transseptal fibers are present even in cases of extreme periodontal bone loss.
- During surgical procedures, these fibers form a firm covering over the bone, which is encountered after removing the superficial granulation tissue.
Periodontal Bone Defects
Ledges
- Plateau-like bone margins caused by resorption of thickened bony plates.
Reversed Architecture
- Loss of interdental bone, including facial and/or lingual plates, without loss of radicular bone, resulting in a reversal of the normal architecture.
Furcation Involvement
- Invasion of the bifurcation and trifurcation of multirooted teeth by periodontal disease.
- Classified into four grades: incipient, partial, total, and through and through opening of the furcation.
Bulbous Bone Contours
- Bony enlargements caused by exostoses or buttressing bone formation.
Fenestration and Dehiscence
- Isolated areas of root denuded of bone with intact margin (fenestration) or loss of bone margin (dehiscence).
Factors Determining Bone Morphology in Periodontal Disease
Factors Related to Teeth
- Morphology of the tooth (thickness of root, thickness of bone, and short root trunk).
- Position of the tooth in the arch (thickness of lingual plate, thin buccal plate).
- Distance between teeth (thin interdental bone).
Factors Related to Bone
- Exostoses (outgrowths of bone).
- Normal variation of bone (thickness, width, and crestal angulation of interdental septa, thickness of facial and lingual alveolar plates, presence of developmental anomalies, and increased thickness of alveolar bone margins).
- Trauma from occlusion (factor in determining the dimension and shape of bone deformities).
- Buttressing bone formation (bone formation in an attempt to buttress bony trabecular weakened by resorption).
Bone Destruction
- Controlled by the pathogenic potential of plaque, host resistance, degree of fibrosis of gingiva, width of attached gingiva, amount of gingival fibers, reactionary fibrogenesis and osteogenesis, and reparative activity.
- Not a process of necrosis, but involves the activity of vital cells as osteoclasts and mononuclear cells.
Mechanisms of Bone Destruction
- By bacteria and host-mediated factors released by inflammatory cells.
- Direct action: bacteria inside plaque differentiate progenitor cells into osteoclasts.
- Indirect action: release of mediators that act as co-factors in bone resorption, destroy bone by chemical action, and inhibit maturation of osteoblasts.
Periods of Destruction and Remission in Bone Loss
- Bursts of destructive activity are associated with subgingival ulceration, acute inflammatory reaction, and changes in the composition of bacterial plaque.
- Periods of remission coincide with the formation of dense, unattached, non-motile, gram-positive organisms and tissue invasion by one or several bacterial species.
Radius of Action
- Local factors causing bone resorption should be present close to the bone surface (1.5-2.5 mm) to exert their action.
Rate of Bone Loss
- In patients with poor oral hygiene, the rate of bone loss is 0.2 mm per year for facial surfaces and 0.3 mm per year for proximal surfaces.
- According to Loe, yearly clinical attachment loss (CAL) can be classified into mild, moderate, and severe periodontitis.
This quiz covers the extension of inflammation from marginal gingiva to the supporting structure, leading to periodontitis, and the pathway of inflammatory exudate affecting bone resorption.
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