Microbiology Flashcards
Definition of caries
Biofilm-induced acid demineralization of enamel or dentin, mediated by saliva
Interaction of cariogenic microorganisms (M.S.) and fermentable carbohydrates (sucrose) induces demineralization
4 types of transmission of cariogenic bacteria:
- Direct saliva: kissing
- Indirect objects: sharing utensils, pacifiers
- Vertical from caregiver. MS genotype in infants identical to moms in 24-100% of pairs in 17 studies
- Horizontal from siblings/children @ daycare. One S-ECC study showed non-maternal MS genotypes in 74% children
What is colonization of bacteria related to?
Magnitude of inoculum
Frequency of inoculum
Minimum infective dose
Can MS colonize pre-dentate infants?
Yes, in furrows of tongue, associated with Bohn’s nodules.
Earlier transmission increases caries risk.
Mean age of MS colonization in dentate infants is 15.7 months
What bacteria is responsible for initiation of caries?
m.s.
What bacteria is responsible for caries progression?
Lactobacillus (opportunistic)
What bacteria may be responsible for smooth surface caries/rampant caries?
S. Sobrinus
Below what pH does demineralization occur?
5.5
What are the zones of the early carious lesion in enamel?
- Surface – relatively unaffected, 5-10% mineral loss (remin) 2. Body – 60% principal area of mineral loss (demin) 3. Dark zone – intermediate area of mineral loss (remin) 4. Translucent zone – 5-10% mineral loss, deepest zone (demin) 5. Normal enamel (remin lesion is stronger than original bc fluorhydroxyapatite is more resistant to acid erosion)
What is the caries sequence?
- Mandibular molars 2. Maxillary molars 3. Maxillary anteriors
Primary teeth have (lower/higher) mineral content and therefore (more/less) rapid progression of caries.
Lower mineral, more rapid
also thinner enamel and dentinpulp larger in relation to tooth size
flat contacts make clinical diagnosis difficult
Caries risk is increased in children with GERD because acid causes erosion of teeth
The statement and the reason are correct
The statement and the reason are incorrect
The statement is correct but the reason is incorrect
The statement is incorrect but the reason is correct
Answer: A. the statement and the reason are correct Unlike dental caries, where the demineralization is caused by an acidic environment in GERD is due to the reflux of hydrochloric acid from the stomach (Figur
What are the differences in gingival tissues between primary and permanent periodontium?
Primary dentition gingival tissues:
- Papilla well keratinized, + spacing => interdental saddle rather than col
- Marginal gingiva deeper sulcus, thicker/rounded free gingival margin, flaccid, retractable
- Attached gingiva less dense, less keratinized, 35% stippling, 85% retrocuspid papilla
- Alveolar mucosa more red, width increases with age/eruption
Primary dentition periodontium:
- PDL wider, less dense
- Alveolar bone has fewer trabeculae, larger marrow spaces, is less calcified
- Junctional epithelium thicker
- More leukocytes in connective tissue
- More dense collagen
*No differences in width of the free gingiva or thickness of epithelium
Where do retrocuspid papilla occur?
Lingual to mandibular canines
usually bilateral
considered a variation of normal
disappear with age
female predilection
Gingivitis peaks when?
At puberty (nearly universal)
increased inflammatory response to plaque
Is gingivitis reversible?
Yes there is no loss of attachment or boneYes there is no loss of attachment or bone
Etiologic factors of gingivitis
Plaque dependent
individual susceptibility
hormonal factors like pregnancy, puberty, oral contraceptives)
local factors (crowding, ortho, mouth breathing, transition)
Gingivitis bacteria in children:
“ACLS”
A - Actinomyces sp.
C - Capnocytophaga sp.
L - Leptotrichia sp.
S - Selemonas sp.
What is the treatment for a gingival abscess?
Clean sulcus / debride / CHX
Caused by embedded foreign object, abscess on marginal gingiva or interdental papilla, localized and painful
Vitamin C Deficiency presentation
Spongy, edematous, bleeds spontaneously,
impaired wound healing
Tx: treat underlying deficiency, plaque control
Necrotizing periodontal disease has a frequency of
<1% in North American and European children
2-5% in certain populations from developing areas of Africa, Asia and South America
Does NPD (necrotizing periodontal disease) present with pain?
Yes
+marginal/interproximal necrosis
fetid odor, pain, bleeding, bone loss, fever, lymphadenopathy, increase in plasma cortisol levels
What are four Diff Dx for the cause of ANUG
Neutropenia
Leukemia
HIV
Malnutrition
Treatment of NPD
Determine if underlying systemic disease
Mechanical debridement (ultrasonics effective)
OHI
NSAIDs for pain
Chlorhexidine oral rinse
10% povidone iodine, antifungals (Flaitz lecture)
Penicillin/ Metronidazole if febrile
careful follow up (q3-4 months)