formation of gingivitis and periodontitis

Question 1

what is plaque?

Answer 1

plaque is a biofilm which is a complex microbial community found on the tooth surface

Question 2

describe how plaque forms

Answer 2

• within seconds a pellicle made predominantly from salivary glycoproteins forms on the tooth surface
• within minutes pioneers species including gram + streptococci species such as sanguis and oralis attach to the pellicle
• as the biofilm matures more gram + filaments and rods attach including actinomyces and lactobacilli species
• within 24 hrs streptococci species dominate
• as the plaque matures and thickens the subgingival biofilm is established
• this is a more anaerobic biofilm made up of GNAB such as pg, pi, fn, tf and the pocket biofilm becomes more motile and destructive with spirochetes such as td forming at the base of the pocket.
• at this point gingivitis is established and can either regress, progress or stay the same.

Question 3

what is a biofilm?

Answer 3

a complex microbial community found on a solid surface (tooth surface).

Question 4

what are the signs of clinical gingival health?

Answer 4

• coral pink and firm gingivae
• ID papillae exactly fill ID space
• stippling due to tight collagen fibres
• knife-edge margins
• less than 10% BOP

Question 5

what does clinical gingival health look like histologically?

Answer 5

low levels of neutrophils and GCF fluid known as normal immunological surveillance as plaque accumulates as soon as teeth are cleaned therefore low levels of inflammation found even in health.

Question 6

what is gingivitis?

Answer 6

plaque induced gingival inflammation and is reversible

Question 7

how does gingivitis form?

Answer 7

gingivitis is plaque-induced inflammation. Most people will develop gingivitis at some point in their lives but the quantity of plaque and time it has remained undisrupted on the tooth surfaces to cause gingivitis varies between individuals based on their susceptibility to plaque.

Question 8

what are the clinical signs of gingivits?

Answer 8

• bop
• erythema and odeoma of gingivae
• loss of stipling
• overfilled ID papillae
• rolled margins
• false pocketing
• reversible with good OH

Question 9

what is periodontitis?

Answer 9

chronic inflammation of the periodontium that is initiated by plaque which leads to destruction of the periodontium and bone loss- it is an irreversible condition meaning once a perio pt always a perio pt.

Question 10

how does periodontitis form?

Answer 10

initiating factor is plaque but periodontitis is a multifactorial disease and not everyone will go onto develop periodontal disease after gingivitis. The progression from gingivitis is not entirely known but involves an individuals susceptibility to the disease, associated risk factors and the host response to plaque accumulation which with periodontal disease causes around 80% of damage to the periodontium aiming to prevent invasion of bacteria into deeper tissues.

Question 11

what is found in a periodontal pocket?

Answer 11

GNAB including aa, pi, fn, pg, tf, td

Question 12

what are gram stains?

Answer 12

+= thick peptidoglycan cell wall retains crystal violet stain= purple under microscope

-= thin peptidoglycan cell with does not retain crystal violet dye= appears red/pink under microscope

Question 13

how is susceptibility measured?

Answer 13

by assessing age and OH against the severity of disease.

Question 14

what evidence is there that plaque accumulation causes gingivitis?

Answer 14

lowes experiment- 12 dental students

Question 15

what evidence is there that GNAB cause periodontitis?

Answer 15

socranskys experiment

ligature induced periodontitis in dogs and monkeys

Question 16

what are the differences between supragingival and subgingival plaque?

Question 17

what is GCF?

Answer 17

gingival crevicular fluid

• derived from serum
• protective as it washes bacteria from the gingival sulcus
• contains immune cells which address plaque bacteria
• contain components such as IgA and IgG.

Question 18

what are the clinical signs of periodontal disease?

Answer 18

• BOP
• true pockets
• ID recession
• radiographic bone loss
• LOA due to migration of JE
• mobility
• halitosis
• gingival shrinkage /
• furcation involvement
• irreversible once a perio pt always a perio pt

Question 19

how does the bacteria induce an the host response?

Answer 19

• releasing enzymes such as collagenases that breakdown collagen
• releasing acids
• releasing endotoxins
  which are released when bacteria is killed- the most potent stimulator of the inflammatory response is LPS which are found on the cell wall of GNAB.
• release signalling molecules such as cytokines which are pro-inflammatory cells.
  ALL OF WHICH LEAD TO TISSUE DESTRUCTION

Question 20

what does the host response release in response to invading bacteria?

Answer 20

• enzymes
• acids
• toxins
• signalling molecules

all released in an attempt to protect underlying tissues from deeper bacterial invasion however this leads to 80% of periodontal destruction as it also leads to tissue damage. Only way to disease is to remove plaque and prevent further tissue destruction.