Gingivitis: Experimental Evidence

Question 1

What is a study that shows the relationship between plaque & gingivitis?

Answer 1

Loe, Theilade and Jensen (1965)

Method

• 12 dental students
• professional scaling & polishing
• stop OH for 21 days
• Plaque & gingival indices measured
• composition of plaque examined
• Tooth brushing recommenced
• Indices and plaque quality still monitered

Question 2

What plaque index did Professor Harald Loe create in this experiment?

Answer 2

Qualitative ranked scale;

0 = no plaque in gingival area

1 = thin film of plaque (seen by running probe along tooth)

2 = moderate amounts of plaque (seen with naked eye)

3 = gross depositis on the tooth

Question 3

What are the conclusions of Loe, Theilade and Jensen (1965)?

Answer 3

Ceasing OH leads to

• plaque accumulation
• gingivitis

Clinically obvious ginigivitis appeare

• 10-21 days

Plaque composition changed

• more filaments, more anaerobes & more spirocaetes

Reversible

• OH restarted, plaque was lost & gingivae returned to health

Question 4

What is a study on Chlorohexidine?

Answer 4

Leo & Schiott (1970)

Method

• basically identical
• OH resarted with chlorhexidine rinse

Results

• Chlorhexidine removed plaque & returned to gingiva to health

Significance

• link between plaque & gingivitis confirmed
• excluded the idea that mechanical stimulation of the gingivae was involved

Question 5

What is a Toothbrushing frequency case study?

Answer 5

Lang, Cumming & Loe (1973)

Method

• dental students
• brush at
  
  • 12 hr intervals
  • 48 hr intervals
  • 72 hr intervals
  • 96 hr intervals

Question 6

What does the plaque theory show?

Answer 6

• Microorganisms > in an individual with inflamed gingiva
• Microorganisms associated with an inflamed gingiva site > healthy gingiva site
• Topical/systemic antimicrobials reduced gingival inflammation
• bacteria demonstrated to be psthogens
• bacterial cultres produce enzymes which can damage gingival & periodontal tissue

Question 7

What is the Plaque Hypotheses?

Answer 7

Specific - Loesche 1976 & 79 also Socransky

• single pathogen
• plaque without a specific microorganism non-[athogenic
• candidated
  
  • Actinomycetes
  • Spirochaetes
  • GNABs
• control/ elimination
  
  • no evidence removing one species prevents disease

Question 8

What are the 3 models of Plaque Hypotheses?

Answer 8

Specific

Non-specific

Ecological

Question 9

What does the Non-specific Hypotesis state?

Answer 9

Theilade 1986

• No single organism responsible
• Bacerial proliferation overcomes host resistance
• Combination of virulence factors
• Control/Elimination
  
  • total plaque control
  • scaling and root planing

Question 10

What is the Ecological Plaque Hypotheses?

Answer 10

Marsh 1991 & 94

• All bacterial species may contribute
• Enviromental conditions leads to nuild of virulent bacteria/virulence factors
• variety/any of plaque populations can cause gingivitis
• species more linked to destructive periodontitis
  
  • 6-7 species in majority cases
• control/elimination

Question 11

What are some specific species in the Plaque Hypotheses?

Answer 11

• Porphyromonas gingivalis
• Prevotella intermedia
• Tannerella
• Fusobacterium nucleatum
• Aggregatibacter actinomycetemcomitans