ODP 3 UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS COMPLETE STUDY
GUIDE
●● Identify plaque retention factors
Answer: -cracks in enamel, anatomical defects
-deep pits/fissures
-restorations
-furcations
-malocclusion, tooth positioning
-oral appliances
-recession
-caries and calculus
●● Explain the development of plaque
Answer: - 0-4 hours, scattered attachment of single cell bacteria to
acquired pellicle
- 4-24 hrs, initial bacteria colonizing are prodominently aerobic, adhere
to pellicle via adhesins, distinct micro colonies begin to form
-24 hrs, environment becomes gram negative, early colonisers have
lower O2 levels in biofilm
- 3-7 days, colonisation is more dense, plaque grows via proliferation
and coaggregation
,- 7+ days, gram -ve anaerobic bacteria increase, spirochetes found in
mature plaque, do not like O2 so usually found in gingival crevice
●● Describe the composition of mature plaque
Answer: -mainly gram -ve
- mainly anaerobic
-70% microorganisms
- 30% intermicrobial matrix
●● Describe the factors affecting the development of plaque
Answer: - pellicle, influences interaction between itself and colonising
bacteria
- saliva, when salivary flow is reduced organisms within biofilm
undergo changes that lead to inflammatory changes
-diet, soft sugary diet encourages plaque due to polysaccharide
formation
-OH/chemical control, plaque around gingival crevice provides nutrients
for subgingival plaque
-PRFs
-location
-metabolism of microbial community
●● Explain the term biofilm
,Answer: An organised bacterial colony which develops at solid/liquid or
air/liquid interface
●● Outline the classification of calculus
Answer: Supragingival
- coronal to gingival margin
Subgingival
-below gingival margin
●● Describe the composition of calculus
Answer: - 70-80% inorganic compounds (hydroxyapatite, whitlockite,
octa calcium phosphate, brushite)
- 20-30% organic compounds of which approx. 85% cellular and 15%
extracellular
●● Explain the nucleation/seeding theory of calculus formation
Answer: -similar to formation of a pearl
-something in organic matrix acts as seeding agent
-seeding agent induce foci of calcification (epitaxis)
●● Other than nucleation/seeding theory, what is an alternative theory of
calculus formation?
Answer: Precipitation theory
, ●● Describe the structure of calculus
Answer: -forms in layers more or less parallel with tooth surface
-layers of pellicles between calculus
-incremental lines
●● Explain how calculus may attach to the tooth
Answer: -acquired pellicle
-irregularities of tooth surface
-enamel irregularities
-cementum irregularities
-tooth/root morphology
-subgingival calculus
-PRFs
●● Explain the significance of calculus
Answer: -PRF
-acts as resevoir for toxins from bacterial plaque
-associated with perio
-aggravating factor in disease progression
-always covered by layer of plaque
-may inhibit drainage of inflammatory products
CORRECT ANSWERS COMPLETE STUDY
GUIDE
●● Identify plaque retention factors
Answer: -cracks in enamel, anatomical defects
-deep pits/fissures
-restorations
-furcations
-malocclusion, tooth positioning
-oral appliances
-recession
-caries and calculus
●● Explain the development of plaque
Answer: - 0-4 hours, scattered attachment of single cell bacteria to
acquired pellicle
- 4-24 hrs, initial bacteria colonizing are prodominently aerobic, adhere
to pellicle via adhesins, distinct micro colonies begin to form
-24 hrs, environment becomes gram negative, early colonisers have
lower O2 levels in biofilm
- 3-7 days, colonisation is more dense, plaque grows via proliferation
and coaggregation
,- 7+ days, gram -ve anaerobic bacteria increase, spirochetes found in
mature plaque, do not like O2 so usually found in gingival crevice
●● Describe the composition of mature plaque
Answer: -mainly gram -ve
- mainly anaerobic
-70% microorganisms
- 30% intermicrobial matrix
●● Describe the factors affecting the development of plaque
Answer: - pellicle, influences interaction between itself and colonising
bacteria
- saliva, when salivary flow is reduced organisms within biofilm
undergo changes that lead to inflammatory changes
-diet, soft sugary diet encourages plaque due to polysaccharide
formation
-OH/chemical control, plaque around gingival crevice provides nutrients
for subgingival plaque
-PRFs
-location
-metabolism of microbial community
●● Explain the term biofilm
,Answer: An organised bacterial colony which develops at solid/liquid or
air/liquid interface
●● Outline the classification of calculus
Answer: Supragingival
- coronal to gingival margin
Subgingival
-below gingival margin
●● Describe the composition of calculus
Answer: - 70-80% inorganic compounds (hydroxyapatite, whitlockite,
octa calcium phosphate, brushite)
- 20-30% organic compounds of which approx. 85% cellular and 15%
extracellular
●● Explain the nucleation/seeding theory of calculus formation
Answer: -similar to formation of a pearl
-something in organic matrix acts as seeding agent
-seeding agent induce foci of calcification (epitaxis)
●● Other than nucleation/seeding theory, what is an alternative theory of
calculus formation?
Answer: Precipitation theory
, ●● Describe the structure of calculus
Answer: -forms in layers more or less parallel with tooth surface
-layers of pellicles between calculus
-incremental lines
●● Explain how calculus may attach to the tooth
Answer: -acquired pellicle
-irregularities of tooth surface
-enamel irregularities
-cementum irregularities
-tooth/root morphology
-subgingival calculus
-PRFs
●● Explain the significance of calculus
Answer: -PRF
-acts as resevoir for toxins from bacterial plaque
-associated with perio
-aggravating factor in disease progression
-always covered by layer of plaque
-may inhibit drainage of inflammatory products
