Periodontitis Flashcards
True of false: attachment loss is normal in the ageing process
True, through a lifetime accumulation of attachment loss (e.g. recession, continuous tooth eruption).
Why is smoking a major risk factor for periodontitis? (very simplified MoA)
- Nicotine causes vasocontriction
- Less nutrition to the bone and gums
- Bone resorption over time
True or false: Biofilm is necessary for periodontitis to occur.
True. (The host also needs to be susceptible)
What causes destruction of periodontium in periodontitis?
Bacterial toxins and enzymes AND host-mediated immune response
What THREE bacteria are in the “Red Complex”?
- Porphyromonas Gingivalis (Pg)
- Tanerrella forsythus (Tf)
- Treponema denticola (Td)
Bonus (in the orange complex):
- Aggregatibacter actinomycetemcomitans (Aa)
What are the x roles of JE?
LOOK AT OLD LECT NOTES TO ADD
- Large intercellular spaces to let PMNs and biofilm products in (for detection)
What specifically activates the immune system to cause periodontitis?
Lipopolysaccharide (LPS) from the cell wall of gram negative bacteria together with other products of plaque/biofilm.
Describe TWO things that occur when the JE is reacting to LPS.
- JE release cytokines (IL-8, TNFa, IL-1a, PGE2, MMP)
- Perivascular mast cells release histamine causing endothelium to release IL-8
What does Matrixmetaloproteinase (MMP) do?
Breaks down collagen and other soft tissues
NOTE: does not really break down hard tissue
How are macrophages recruited to the periodontal site and what do they do when they get there?
- Recruited by serum proteins (eg. complement) that are released into the blood/CT via vascular reaction to plaque
- Macrophages regulate activity of other cells (wbc, fibroblasts, osteoclasts) via cytokines (IL-1b, IL-6/10/12, TNFa, PGE2, MMP, IFNg) and chemotaxins (MCP, MIP, RANTES)
What are the FOUR stages of periodontitis pathogenesis?
- Initial reaction to plaque (JE and mast cells react to LPS, IL-8 attracts PMNs)
- Activation of Macrophage (monocytes recruited, turn into macrophages and release lots of cytokines. Leukocytes also recruited)
- Upregulation of inflammatory cell activity (plasma cells, T-cells, PMNs and fibroblasts release cytokines - plasma cells dominate)
- Initial loss of attachment (cytokines encourage macrophage -> preosteoclast, then RANKL from T-cell and osteoblast encourage preosteoclast -> osteoclast = net bone resorption)
What medication and dose/duration can be used to manage bone loss in periodontitis?
Doxycycline
- 20mg twice daily for six weeks
Name FOUR things that influence Macrophage activity.
- Genetics (hyperresponsive Macrophage phenotype)
- Smoking (same effect)
- Uncontrolled diabetes
- NSAIDS (suppresses PGE2 production)
What FOUR effects can antibodies have?
- Aggregate microbes
- Prevent adherence of bacteria to epithelium
- Work with complement to kill microbes
- Permit efficient phagocytosis by PMNs
NOTE: people who can mount an effective antibody response may be less susceptible to periodontitis
Name FIVE proinflammatory cytokines
- IL-1b
- TNFa
- IFNg
- PGE2
- MMP
Name FOUR antiinflammatory cytokines
- IL-1ra
- IL-10
- TGFb
- TIMPs
What are FOUR main cytokines that regulate osteoclasts?
Which TWO are most relevant to periodontitis?
- PTH
- Calcitonin
- PGE2
- RANKL
NOTE: PGE2 and RANKL are the most relevant to perio
What are TWO sources of RANKL?
- T-cells
- Osteoblasts
What are TWO ways to decrease osteoclast activity?
- Osteoprotegerin (OPG) from osteoblasts
- Bisphosphonates
What is the dentally related risk when pts are on bisphosphonates?
How long does this risk last for after stopping bisphosphonates?
On bisphosphonates, the bone becomes ‘frozen in time’ and has a tendency for necrosis after extractions.
The effect of bisphosphonates can last up to 10 years.
What is meant by infrabony and suprabony pockets?
infrabony = vertical/angular bone loss suprabony = horizontal
Where are the THREE walls positioned in a 3-walled defect?
Interdentally, palatally/lingually and buccally.
Define grades of furcations.
Grade I - 1mm
Grade II - More than 2mm
Grade III - through and through
What walls are lost when progressing from a 3 walled defect to 2 and from a 2 to 1 walled defect?
3 –> 2 we lose the interdental wall.
2 –> 1 we lose the buccal wall (loss of cortical bone).
How much is normal/physiological tooth movement?
0.2mm
Link PDL, bone loss, occlusive force and tooth mobility
Occlusive force applies stress to the PDL which then relax upon force release, allowing for a certain degree of tooth mobility.
Normally this is not a significant amount of mobility because only the coronal third and apical third of PDL is affected. But when bone loss occurs, only the apical third of PDL is left over, producing more mobility.
True or false: generally it is a good idea to still splint teeth that are mobile but not increasing in mobility, to prevent worsening of mobility.
False. We mainly splint teeth that are worsening in mobility.
Name THREE types of tooth splints.
- Wire splint
- CR splint
- acrylic splint
Wire splints are semi-rigid splints while CR splints are fully rigid. What is the risk of fully rigid splints?
Lack of PDL movement/use can lead to ankylosis of tooth roots to alveolar bone.
Define the THREE grades of mobility.
Grade I - up to 1mm horizontal movement
Grade II - >1mm horizontal
Grade III - horizontal and vertical movement
What positions are the roots and furcal entrances of upper first molars.
Roots: two buccal one palatal
Furcations: buccal, DP, MP
What positions are the roots and furcal entrances of lower first molars.
Roots: mesial and distal
Furcations: buccal, lingual
What positions are the roots and furcal entrances of two rooted upper first premolars?
Roots: buccal and palatal
Furcations: mesial and distal
What’s so bad about furcation involvement?
The area is extremely hard to clean -> entrypoint for bacteria
From where to where is root trunk measured?
CEJ to furcation
What’s so bad about a short root trunk?
Higher furcation meaning easier to get furcation involvement.
What is the difference between hemisection and root resection?
Hemisection = separate portions of root+crown
Root resection = removal of a root
How do we usually manage furcation involvements?
- Root surface debridement
- OHI
What is a primary risk factor for periodontitis? (primary = direct cause)
Specific pathogens from plaque (ie. red complex)
What are THREE non-alterable secondary risk factors for periodontitis?
- Genetics (e.g. IL-1 gene polymorphism)
- Gender
- Age