periodontal progression

Question 1

what causes gingivitis?

Answer 1

• gingivitis is plaque induced gingival inflammation
• gingivitis is caused by the accumulation of plaque and the amount of plaque and time it has been present varies between individuals based on their susceptibility to plaque. This tips the scale from a symbiotic relationship between plaque and OH to a dysbiotic relationship.

Question 2

what is susceptibility?

Answer 2

susceptibility is a measure of age and OH relative to the severity of disease present

Question 3

how does gingivitis progress to periodontitis?

Answer 3

gingivitis can progress to periodontitis which causes inflammation of the periodontium. Periodontitis is a multifactorial disease and therefore progression depends on the presence of plaque, and individuals susceptibility and host response to plaque and associated risk factors.

Not everyone will progress to periodontitis but in any given population 10% of individuals will develop severe perio even with good oh, 10% of people are resistant to perio even with poor OH and 80% will have slowly progressing perio if appropriate tx is carried out.

Question 4

what are socranksys theories of progression?

Answer 4

continuous rate theory- describes how destruction continues at at a gradual rate

random burst theory- destruction occurs in random episodic bursts and different sites can have different rates of activity, at different times and can occur for diff lengths of time. Sites then go through periods of no activity.

asynchronous multiple burst theory- where destruction occurs during a specific period of time for e.g during illness and then undergoes long periods of no activity

rates of progression can differ among individuals and within different sites within the same individual- you can get RAL- rapid and over short period of time- often if high sus and GAL slow progression over long period of time- often in low sus

Question 5

describe the progression to periodontitis

Answer 5

initial lesion
early lesion
established lesion
advanced lesion

Question 6

what happens during the initial lesion ?

Answer 6

• no clinical signs of gingivitis
• occurs within 24-48 hrs
• vasodilation
• increase in neutrophils
• increase in GCF
• inflammatory infiltrate is confined to CT below JE

Question 7

what happens during the early lesion?

Answer 7

• no clinical signs of gingivitis
• within 1 week
• begin to see an increase in inflammatory infiltrate including cytokines, immunoglobulins and t lymphocytes
• further increase in neutrophils and GCF
• begin to see decreased in fibroblasts and breakdown of collagen though this causing minimal damage
• this damage is reversible

Question 8

what happens during the established lesion

Answer 8

• seen as clinical gingivitis
• JE epithelium is replaced with pocket epithelial and is no attached to the tooth though there is no LOA
• plaque migrates deeper into the pocket with an increase in GNABs
• the JE becomes ulcerated
• GCF, neutrophils, immunoglobulins, t lymph increase in numbers
• the inflammatory infiltrate largely replaces the CT below the JE and there is further loss of fibroblasts and collagen

Question 9

what happens during the advanced lesion?

Answer 9

this is seen as clinical periodontitis
- the JE migrates apically onto the root surface following damage and destruction of PDL fibres causing LOA
- plaque migrates into deeper pocket and GNAB increase
- cytokines and prostaglandins produce host resorption factors with activation of osteoclasts which break down bone irreversibly

Question 10

what do neutrophils do?

Answer 10

they engulf bacteria and release their contents to kill the bacteria through a process known as phagocytosis
- they then undergo apoptosis

Question 11

what do cytokines do?

Answer 11

cytokines such as IL and TNF are pro- inflammatory signalling molecules which attract cells to the site of inflammation

Question 12

describe the innate immunity

Answer 12

• non specific
• includes the epithelial barrier to prevent bacteria entering
• predominant cells include neutrophils, macrophages and dendritic cells

Question 13

what are the functions of:

neutrophils
macrophages
dendritic clls

Answer 13

neutrophils and macrophages engulf bacteria through a process known as phagocytosis

dendritic cells are antigen presenting cells- they also engulf bacteria through phagocytosis and present antigens on its surface to activate t lymph and help establish adaptive immunity

Question 14

describe adaptive immunity?

Answer 14

• specific immunity
• the predominant cells are b lymph and t lymph

Question 15

what is the function of b lymph?

Answer 15

produce antibodies including IgG,A,M,E,D

Question 16

what are the functions of antibodies ?

Answer 16

• bind to and inactivate toxins through process known as neutralisation
• bind to pathogens allowing them to be recognised by phagocytic cells through a process known as opsonisation

Question 17

what is the inflammatory response?

Answer 17

• initial response to foreign pathogen
• triggers immune response
• can be acute or chronic

Question 18

describe acute inflammation?

Answer 18

• rapid onset
• causes vasodilation, inc GCF, redness, swelling, heat, LOF and pain
• predom cells are neutrophils

Question 19

describe chronic inflammation ?

Answer 19

• occurs when stimulus causing acute inflammation is not removed
• occurs over long period of time
• cause swelling and redness
• predominant cells include t/b/mac/plasma

Question 20

how do Pg evade the immune reponse?

Answer 20

• capsule to avoid recognition by IR
• release gingipains which are proteases which degrade host cells such as cytokines and Ig
• contain fimbrae which aid attachment to periodontal tissues

Question 21

how do Td evade IR?

Answer 21

• release proteases which degrade host cells including Ig and cytokines
• are spirochetes than have flagella which make them motile

Question 22

how do Tf evade ER?

Answer 22

• produce proteases which degrade host cells such as Ig and cytokines
• can change their surface proteins to avoid recognition