Chapter 17

Question 1

What is a local factor that increases plaque biofilm retention?

Answer 1

Rough edge on a restoration harbors plaque biofim and makes it difficult to remove w/ a brush and floss

Question 2

What is a local factor that increases plaque biofilm pathogenicity?

Answer 2

Calculus deposits harbor plaque biofilm, allowing the biofilm community to grow uninhibited for an extended period

Question 3

What are some local factors that can inflict damage to the periodontium?

Answer 3

• Ill-fitting dental appliance that puts excessive pressure on the gingiva
• History of traumatic toothbrushing
• Trauma from occlusion
• High frenal attachment

Question 4

Characteristics of calculus

Answer 4

• Mineralization of plaque 48 hours to 2 weeks after biofilm formation
• Irregular porous surface for bacterial biofilm retention
• Fixed source for plauqe accumulation proximal to the tissue leads to gingival inflammation
• Difficult to contro gingivitis or perio in presence of deposits

Question 5

What is the composition of calculus?

Answer 5

70-90% inorganic-> Calcium phosphate, calcium carbonate, magnesium phosphate
Organic-> Plaque biofilm, dead epithelial cells, dead WBCs and living bacteria

Question 6

What ar ethe 3 types of calculus?

Answer 6

“Brushite”- Crystaline, newly formed
Crystalline octacalcium phosphate- < 6mos

Crystalline hydroxyapatite- > 6mos

Question 7

Modes of calculus attachment

Answer 7

• By pellicle- on enamel surfaces, easily removed
• By irregularities in tooth surface- Cracks, openings where PDL fibers were attached, grooves from instrumentation etc
• By direct contact of calcified component and tooth surface- matrix of calculus interlocked w/ inorganic crystals of the tooth

Question 8

What is biologic width?

Answer 8

The zone of soft tissue occupied by the JE and the CT fibers immediately apical to the JE
Portion of the periodontium coronal to the alveolar crest
* Gingival sulcus- 0.69mm
* JE- 0.97mm
* CT attachment- 1.07mm
=2.04mm (~3mm incl. sulcus)

Question 9

When does violation of biologic width occur?

Answer 9

If restoration margins encroach on this zone

Question 10

What does this picture depict?

Answer 10

Acute invasion

Question 11

What does this picture depict?

Answer 11

Chronic invasion

Question 12

What is occlusal trauma?

Answer 12

Direct damage to the periodontium from excesive biting forces on teeth
AB resorption can result from increased pressure
Can be more rapid destruction by preexisting perio

Question 13

Clinical signs of occlusal trauma

Answer 13

• Tooth mobility
• Sensitivity to pressure
• Migration of teeth

Question 14

Radiographic signs of occlusal trauma

Answer 14

• Widened, funnel-shaped PDL
• Angular alveolar bone resorption

Question 15

What is primary occlusal trauma?

Answer 15

• Excessive occlusal forces on an intact periodontium w/ no previous history of periodontal breakdown
• Widened PDL
• Tooth mobility
• Tooth/jaw pain
• Reversible when traua is removed
• Trauma may be expressed as wear to teeth rather than mobility

Question 16

What is secondary occlusal trauma?

Answer 16

Normal (or excessive) forces on a periodontium compromised by perio
Inflammation+OT= rapid bone loss
Additional damage to periodontium can occur due to lateral forces on teeth w/ attachment loss

Question 17

WHat are functional occlusal forces?

Answer 17

Normal chewing forces

Question 18

What are parafunctional habits?

Answer 18

Tooth-tooth cvontacts outside of eating:
* Clenching
* Grinding/bruxing
* May be conscious or unconscious, or nocturnal
* Therapy: Selective occlusal adjustement and/or occlusal appliance fabrication

Question 19

What is abfraction?

Answer 19

The pathological loss of tooth substance caused by biomechanical loading forces that result in flexure and failure of enamel and dentin at a location away from the loading