Transcript Caries Intro

Daranee Versluis-Tantbirojn
DENT 5302 TOPICS IN DENTAL BIOCHEMISTRY
The caries process
Dietary factor and cariogenic aspects of dental plaque
Plaque fluid and the caries process
Fluoride and dental caries
Anticario mechanisms of fluoride
Fluoride metabolism
Fluoride toxicity
Application of fluoride (& Ca P) in caries control measures
DENT 5302 TOPICS IN DENTAL BIOCHEMISTRY
28 March 2007
Objectives:
• Nature and character of dental caries
• Factors influencing the caries process
• Development of early caries lesion in enamel
• Dentin caries
Outline
Nature of dental caries
History & Epidemiology
Key features of dental caries
Multi-factorial
Site specific
Dynamic
Demineralization-Remineralization
Formation of early enamel lesion
Microscopic features of early enamel lesion
Caries free vs Caries controlled
Dentin caries
Carious
Teeth (%)
Epidemic
1950
Industrialize
20
15
Roman
10
5
0
2000
1000
0
1000
2000
Percentage of carious teeth in English population
Dental caries: the most prevalent infectious disease
• 5x > childhood asthma ; 7x > hay fever
• Affects 85% of adults (>18 years old) in the US
• 80% of caries occurs in 20% of the population
www.surgeongeneral.gov/library/oralhealth/
Underprivileged population?
Less than high school
High school
At least some college
Total children
Evans CA, Kleinman DV (2000).
The Surgeon General's report on
America's oral health: opportunities
for the dental profession.
J Am Dent Assoc. 131: 1721-8.
75% of children aged 5-11 years old were caries-free
70% of 12-17 years old had caries
94% of dentate adults (18 years or older) had caries
The nature of caries has changed:
Rapidly progressing childhood disease
Slow but steadily progressing disease in adulthood
Discussion:
Give some examples of using knowledge and understanding
of dental caries in your future dental practice.
Characters
of caries
Traditional
concept
Dental caries is multifactorial
Cariogenic
bacteria (dental
plaque)
Host factors:
Tooth
Saliva
Diet:
Fermentable
carbohydrate
Characters
of caries
Dental caries is multifactorial
Social class
Modern
concept
Education
Saliva
Microbial
species Biofilm
Biological
determinants
Flow rate
Composition
Buffer
Income
Fluoride
Tooth
Genetic
Time
Behavior
Socioeconomical factors
Diet
Composition
Sugar
Frequency
Knowledge
Attitude
Characters
of caries
Dental caries is site specific
Dental caries: Localized destruction of tooth tissues
Erosion
Why localized?
Tooth morphology affects plaque accumulation
Metabolism of microorganisms in dental plaque (biofilm)
Microenvironment (plaque composition, thickness, diffusion properties)
Access to dietary substrates, saliva, anticaries agents
Characters
of caries
Dental caries is dynamic
Mineral content
Demineralization vs Remineralization
breakfast coffee
break
Net
loss
lunch
snack
brushing
dinner
snack
brushing
Brown spot (Arrested lesion)
• Change in microenvironment
• Reduced plaque accumulation
• Access to saliva
www.recaldent.com
Formation of early enamel lesion
saliva
plaque
sound enamel
subsurface
lesion
acid
H2O
H+ + apatite
OHCa2+
HPO42-
diffuse & dissociate
Ca2+ + PO43- + OH-
PO43Fsurface zone (repair)
Microscopic features of early enamel lesion
1
2
3
1
2
3
4
2
4
34
1
1. Surface Zone
Intact surface 20-100 mm thick, <10% mineral loss
2. Body of the Lesion
Largest zone, highest mineral loss (24%)
3. Dark zone
Very small pores, <10% mineral loss
4. Translucent zone
Advancing front, 1% mineral loss
Clinical appearance: White spot lesion
First clinical sign of enamel caries lesion
Not that early!
300 – 500 mm depth to be visible
Why are we interested in early caries lesion?
At this stage the lesion is reversible
Fluoride and preventive treatment are most effective at this stage
Early carious lesions are reversible
Sound enamel
White spot
Cavitated lesion
Age 8
Age 15
93
74
37
15
26
4
9
19
72
19
111 sound enamel
41 white spots
32 cavitated lesions
(Baker-Dirks, 1966)
Study done in community with water fluoridation
Only 9 of 72 white spot lesions became cavitated after 7 years
More than half of early lesions regressed to ‘normal’ enamel
Dr. J.P. Byers
White spot lesions
around orthodontic
bracketts
Dr. J.P. Byers
Discussion:
‘caries-free’ vs ‘caries-controlled’
Is there a ‘caries-free’ individual?
Q1 Do you have any cavities or fillings
Q2 Do you think you have demin-remin periods?
Progression of Carious Lesion
How long?
Proximal lesions in permanent
teeth can take 3-4 years through
enamel, unless in caries active
0
1
2
individuals. (Pitts, 1983)
Median survival time from
stage 2 to 3 was ~ 3 years
Late teen Danish population
From 2 – 3: 9.2 surface % per year
3
4
From 3 – 4: 2.3 surface % per year
Rampant caries in Mountain Dew drinker
Dentin caries
Microscopic features carious dentin
A = zone of decomposed dentin
B = zone of bacterial invasion
C = zone of demineralization
D = sclerotic dentin
E = reparative dentin
Progression of dentin caries
Demineralization of inorganic
substance
Breakdown of organic matrix
by proteolytic enzymes
Bacterial invasion
Outer carious dentin
Inner carious dentin
Dentin caries
Knoop Hardness Number
Two layers of carious dentin
70 -Outer carious dentin
Inner carious dentin
infected
60 nonremineralizable
uninfected
remineralizable
50 - nonvital
insensitive
40 -
vital
sensitive
Sound dentin
30 20 Turbid
layer
10 -
DEJ
1000
Transparent
layer
Subtrans
parent
layer
2000
Pulp
wall
3000 mm
Crystals in tubule lumen
Bacteria
Odontoblast
Fusayama T, Okuse K, Hosoda H. J Dent Res. 1966;45:1033-46.
Relationship between hardness, discoloration, and microbial invasion in carious dentin.
Discussion:
What do you learn today that can be used in future practice?
1. Why underprivileged population have more caries?
2. What should we do with white spot lesion?
3. How much carious dentin should be removed?
Recommended references
1. Clarkson BH. Introduction to Cariology. Dent Clin North Am
1999;43(4):569-578.
2. Zero DT. Dental Caries Process. Dent Clin North Am
1999;43(4):635-664.
3. Featherstone JD. The science and practice of caries prevention. J
Am Dent Assoc 2000;131:887-899.
4. Gordon Nikiforuk. Understanding Dental Caries 1. Etiology and
Mechanisms, Basic and Clinical Aspects. Basel; New York: Karger
1985. Chapter 10.
5. Gao W, Smales RJ, Yop HK. Demineralisation and remineralisation
of dentine caries, and the role of glass-ionomer cements. Int Dent J
2000;50:51-56.
6. Fejerskov O. Changing paradigms in concepts of dental caries:
Consequences for oral health care. Caries Res 2004;38:182-191.