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Flashcards in Murata/Sensi/Kaur Deck (27)
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1

Dental Caries:

  • most prevalent and costly oral infection worldwide
  • Streptocaccus mutans
    • develop virulent biofilms

2

Streptococcus mutans: Virulence factors

  • Biofilm formation
    • composition
  • Acid production
    • ATPase
  • Glycosyltransferase (GTF)
    • GTF B & C

3

How do we get resident oral microflora:

  • New born mouth is sterile 
    • Main route of transmission=Saliva
    • Vertical transmission of
      • Oral Streptococci and Gram-negative species in children from their mother

 

  • First months: Diversity increases
    • Pioneer species: streptococci salivarius, mitis and oralis 
  • Then: Grame negative anerobes:
    • Prevotella melan
    • Fusobacterium nucleatum
    • Veillenella spp.
  • Teetth Eruption
    • novel habitat for microbial colonization
    • non shedding surface
  • After tooth eruption:
    • S. Mutans
    • S. Sanguinis
  • 19-31 months: colonization of S. Mutans
    • "Winndow of infectivity"
  • increase climax community

4

oral microflora:

  • Microbial Homeostasis=stable 
  • Dynamic equilibrium b/w resident microflora and enviromental conditions 
    • attempt t implant specific strains have failed
  • Change in microflora
    • effect of aging

5

Key factors in S. Mutans Cariogenicity

  • Adherence/colonization factors
  • Acidogenicity
  • Aciduricity

6

Adherence/Colonization factors

  • Sucrose-dependent production of extracellular polysaccharides

7

Acidogenicity:

  • very efficient uptake and metabolism of simple dietary carbohydrates to lactic acid
    • glucose
    • fructose
    • sucrose

8

Aciduricity:

  • maintenance of neutral intracellular pH in an low-pH microenviroment

9

Biofilm formation:

  • initial attachment
  • colonization
  • formation
  • mature biofilm 
  • dispersal/climax

10

Metabolism of dietary sucrose by S. mutans

Sucrose-->Glucose, Fructose-->Lactic acid-->enamel dissolution

11

Microbiology of root surface caries:

  • 60% of people over 60 in the West
  • accompanied by gingival recession
  • soft cemental surfaces-highly susceptable to microbial colonization 
    • irregular and rough surfces 
  • Mainly Lactobacilli 

12

Carious Process

  • disequilibrium b/w demineralization and remineralization
  • helps with biofilm accumulation
  • synergistic acceleration of in cariogenic biofilm community
  • expansion of demineralization with expanded cavitation
  • rapid progresing destruction of tooth structure
  • When careis reach DEJ, it expands rapidly bc dentin is much lesss resistant to acid demineralization

13

What teeth are more susceptible to dental caries

  1. Mandibular 1st molars
  2. 1st maxillary molars, 2nd mandibular molars, 2nd Maxillary molars
  3. 2nd premolars, maxillary incisors, and 1st premolars
  4. Mandibular incisors and canines (least likely

14

Surface susceptibility to caries: 

first mandibular molars

fist maxillary molars 

Maxillary lateral incisors

Secondary recurrent caries

root caries

  • Mandibular molars
    • O>B>M>D>L
  • Maxillary Molars:
    • O>M>L>B>D
  • Maxillary lateral incisors
    • L>B
  • Secondary/recurrent caries
    • gingival margin of restorations
  • Root caries
    • close to gingival margin 

15

Enamel defects:

  • Nutritional deprivation
    • hypoplastic enamel
  • Genetic disorders
    • amelogenesis imperfecta
    • dentogenesis imperfecta
  • High Fever
    • Hypoplastic enamel-white lines
  • Tetracyclines
  • Advanced Fluorosis

16

Other factors affecting tooth susceptibliity 

  • Arch form and tooth position
    • round vs square arch
    • diastema
    • misalignment, overlapping, tippint, rotation

17

Non-cavitated lesion

wHITE SPOT

18

Early lesion

Small well defined, discolored area located at the CEJ

  • White spot 
  • especially at the gingival margin
    • earliest sign of carious lesion

19

Active Lesion

  • Yellow or light brown in color
  • covered by microbial deposits 
  • tooth structure is soft 

20

Slow progressing lesions

  • brown to black in color
  • lether consistency 

21

Inactive/arrested lesion

dark brown and almost black

surface is shiny, smooth, hard on probing

root surface=glossy

22

How long does it take carious lesion to appear

  • enamel: slow in most cases
    • white spot: >2 years
    • Cavitation: > 4 years
  • Most susceptible time: 
    • 2 years after erruption
  • slower when Fluoride exposure is regular 
  • caries progression through dentin may also be slow

23

4 myths of old school restorative dentistry

  1. ALL carious lesions need to be filled
  2. ALL carious lesions progress over. time
  3. restoractions cure caries
  4. placing restordations does more good than harm

24

How should we treat caries: 

  • Modern Caries management: Tx/prevention
    • Chemotherapeutics/remineralization
    • Risk reduction
    • restorative treatment
      • repair defects and aid in plaque control

25

Remineralization factors

  • intact surface
  • buffers calcium and phosphate ions
  • plaque age
  • fluoride

26

Lesion Severity Classification:

  • E0
    • no lesion
  • E1
    • outer half of enamel
  • E2
    • inner half of enamel
  • D1
    • outer third of dentin
  • D2
    • middle third of dentin
  • D3
    • inner third of dentin
  • D4
    • penetrated pulp

27

S Mutans polysaccharide production influence cariogenicity:

  • EPS
    • attachment of cells in plaque matrix 
    • acidic fermentation 
    • soluble or insolube 
  • IPS
    • permits acid production in absence of dietary sugars