Zhaozhao_Diagnostic methods

Question 1

Describe the 2x2 table
(positive predictive value, negative predictive value, sensitivity, specificity)

Answer 1

If the table is:
a | b
c | d
Positive predictive value: Test accurately detects when someone has the disease. (a / a+b)
Negative predictive value: Test accurately detects when someone does not have the disease. (d / c + d)
Sensitivity: True positive rate (a / a+c)
Specificity: True negative rate (d / d+b)

Question 2

Describe the Sillness & Loe ‘63 classification

Answer 2

Grade 0: histologically pristine gingiva (no erythema & no bleeding)
Grade 1: slight erythema; no bleeding
Grade 2: Moderate erythema; bleeding on probing
Grade 3: Severe erythema; spontaneous bleeding and ulceration

Question 3

What percentage of the population has stippling?

Answer 3

Karring & Loe ‘70 : 40%

Question 4

Describe the Silness & Loe plaque index

Answer 4

Silness & Loe ‘64 :
0: No plaque
1: Thin film of plaque discovered by running probe along the gingival margin
2: Visible plaque
3: Abundance of plaque

Question 5

What is the probing error of the periodontal probe?

Answer 5

Goodson ‘86: ~0.8 mm

Question 6

How deeply does the periodontal probe penetrate into the sulcus?

Answer 6

Armitage ‘77:
Healthy tissues: Short of the most apical JE cells
Gingivitis: Short of the most apical JE cells
Periodontitis: goes past the JE cells and enters the CT

Question 7

What is the significance of BOP and who proved this?

Answer 7

Absence of BOP is a predictor of periodontal stability : Lang ‘90

Freq BOP at SPT visits & chance of CALoss:
4/4 -> 30%
3/4 -> 14 %
2/4 -> 6%
1/4 -> 3%
0/4 -> 1.5%

Question 8

Describe the Miller mobility classification.

Answer 8

Class 0 : Physiologic movement
Class 1: Greater than physiologic
Class 2: < 1mm of horizontal movement
movement
Class 3: > 1 mm horizontal movement

Question 9

Describe the Hamp classification for furcation involvements

Answer 9

Hamp ‘75:
Class I: Horizontal loss <3mm
Class II: Horizontal loss >3mm, but not through
Class III: Horizontal loss that is through-and-through

Question 10

What percentage of bone mineral content loss is needed before it is detected on a radiograph?

Answer 10

Ortman ‘82: 30%

Question 11

How long does it take before bone loss is detected on radiographs?

Answer 11

Goodson ‘84: 6 to 8 months
Sig CALoss precedes bone loss by 6-8 months

Question 12

What does the presence of lamina dura signify in a radiograph?

Answer 12

Rams ‘94: Lamina dura presence is a sign of periodontal health. However, its absence lacks diagnostic relevance

Question 13

What diseases appear as a narrowed PDL space? - name 3.
How about a widened PDL space? - name several

Answer 13

Narrow PDL : Hypophosphatemic rickets, fibrous dysplasia, ankylosis
Widened PDL: TFO, scleroderma, hyperparathyroidism, osteosarcoma, Gaucher’s disease, BRONJ

Question 14

Are radiographs an accurate way to measure calculus?

Answer 14

Buchanan ‘87: Nope, only 44% of radiographs showed it. Therefore, radiographs have low sensitivity of detecting calculus.

Question 15

What percentage of cemental tears can be detected on radiographs?

Answer 15

Lin ‘11: Only about half (56.3%)

Question 16

How accurate are radiographic furcation arrows for detecting actual furcation involvements?

Answer 16

Deas ‘06: Sensitivity is 38.7%. However, the specificity is 92.2%. So, the absence of furcation arrows is likely a sign of lack of disease. However, presence of furcation arrows does not necessarily mean there is a furcation involvement.
Positive predictive value & negative predictive values were about 70%
Therefore, not very accurate

FROM THE ARTICLE:
he sensitivity of the furcation arrow image as a diagnostic marker was 38.7%, and the specificity was 92.2%; the positive predictive value of the image was 71.7%, and the negative predictive value was 74.6%. Of the 324 furcations used to compare clinical indices, the agreement of preanesthesia and postdebridement Hamp indices was 0% for degree 3, 83.7% for degree 2, and 98.4% for degree 1 furcation lesions.

Conclusions: These data suggest that the furcation arrow has limited usefulness as a diagnostic marker of furcation invasion. The image is difficult to interpret and highly subjective and can correctly predict furcation invasions only approximately 70% of the time when present on the radiograph. In addition, when furcation invasions are truly present, the furcation arrow is seen in <40% of sites.

Question 17

How do you classify vertical furcation involvement? - name 3 studies.
How does vertical involvement affect tooth loss?

Answer 17

Tarnow & Fletcher ‘84: More vertical involvement means more likely to lose the tooth in 10 years.
Grade A: 0-3mm
Grade B: 4-6mm
Grade C: 7+ mm
10 year tooth loss rates: 9%, 33%, 77%
Tonetti ‘17:
A - in coronal third of root
B - to mid third of root
C - to apical third of root
10 year survival of the treated teeth: 91%, 67%, 23%
Nibali ‘18: Loss to the mid- and apical-thirds greatly increased tooth loss by about 10X. (OR : 9.83)

Question 18

Describe the inflammatory biomarkers:
IL-1, IL-4, IL-6, IL-8, IL-10, TNF-alpha

Answer 18

Biomarker: Source; function
IL-1: Macrophages; Very strong inflammatory stimulator.
IL-4: Tcell, mast cell; anti-inflammatory and Induces TH2 cell differentiation
IL-6: Tcell, macrophage, osteoblast; stimulates osteoclasts
IL-8: Macrophage, epithelial cells; recruit & activate neutrophils
IL-10: monocytes; anti-inflammatory
TNF-alpha: neutrophil, macrophage, lymphocytes; delay neutrophil apoptosis, inhibit bone collagen synthesis, induce collagenases

Question 19

Describe the biomarkers:
MMP-8, MMP-9, TIMP-1, TGF-alpha

Answer 19

Biomarker: source; function
MMP-8: Neutrophils; collagenase
MMP-9: Neutrophils; gelatinase
TIMP-1: neutrophils, macrophage, fibroblast, keratinocytes; inhibits MMP-8
TGF-alpha: macrophages, keratinocytes; regulation of tissues and cells in proliferation, chemotaxis, differentiation, and synthesis

Question 20

Describe the biomarkers:
OPG, RANKL

Answer 20

Biomarker: Source; function
OPG: osteoblasts; inhibits osteoclast formation by competitively inhibiting RANK
RANKL: osteoblasts; binds to RANK on stem cells to form osteoclasts

Question 21

What is the heritability of periodontitis? (Hint: twin study)

Answer 21

Michalowicz ‘00: Compared monozygotic to dizygotic twins. Periodontitis is 50% heritable

Nibali ‘19 also did a systematic review on heritability. Found that gingivitis is not very heritable and periodontitis is likely inherited when there is severe early onset in younger individuals.

Question 22

What is the significance of the IL-1 gene polymorphisms?

Answer 22

Kornman ‘97: IL-1 gene polymorphisms are extremely strong predictors of severe periodontitis (OR: 18.9)

Question 23

What is the limit of CBCT in detecting the buccal bone thickness?

Answer 23

Gonzales-Martin ‘16: 1 mm (unable to detect less than that)

Question 24

What are some experimental non-invasive research equipment that can study periodontal tissues?

Answer 24

Ultrasonic: Can use the B-mode (static) and Color mode (dynamic) Chan ‘17, 18 and several Michigan studies (Barootchi, Tavelli, Majzoub, etc all the academically popular people here
Laser doppler flowmetry: Uses doppler shift and lasers. Is time consuming and experimental only
Optical coherence tomography: Uses a laser and sophisticated software. However, only penetrates shallowly into the tissues