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5. Dental Caries
Demineralization, remineralization
Occlusal lesions can
be arrested by
remineralization
6. Dental Caries
Demineralization, remineralization
recently cleaned front teeth
with signs of demineralization
and gingivitis
after some weeks
remineralization has taken
place and the gingivitis is
healed
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12. Dental Caries
Progression of dentine caries
Bacterial Invasion
1
2
3
Bacteria need to have a source of nutrients,
4 i.e. from the oral environment.
5
6
7 Bacteria are found mostly in the biomass
8
with few being found in the dentine tubules.
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13. Dental Caries
Progression of dentine caries
Crystal Removal Process
1
2
3
4
5
6
7
8
14. Dental Caries
Progression of dentine caries
Crystal Removal Process
1 Acid from fermentation process penetrates
2
the dentine tubules ahead of bacterial
3
4
invasion.
5 This softens the dentine matrix.
6
7
The collagen fibres are reversibly damaged
8
in the dissolution process.
cont’d
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15. Dental Caries
Progression of dentine caries
Crystal Removal Process (cont’d)
1 Continuation of acid production dissolves
2
crystals in the peritubular and intertubular
3
4
dentine.
5 Further continuation of acid production
6
breaks the intermolecular crosslinks of
7
collagen fibres irreversibly.
8
16. Dental Caries
Progression of dentine caries
Defense reaction in dentine
1
2
3
4
5
6
7
8
17. Dental Caries
Progression of dentine caries
Defense reaction in dentine
1 A defence reaction takes place in the
2
dentine.
3
4
Dissolution alters the hydroxyapatite crystals.
5 Crystals with a lower hardness and a lower
6
7
calcium density (= whitelockite) remain.
8
The dentine tubules are blocked by
precipitated intratubular whitelockite crystals.
cont’d
18. Dental Caries
Progression of dentine caries
Defense reaction in dentine (cont’d)
1 These crystals originate from the
2
peritubular and intertubular dentine.
3
4
This process is known as TUBULAR
5 SCLEROSIS.
6
It is seen clinically as yellow-brownish
7
8
discoloration of the dentine.
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19. 70 Outer Carious Dentine Inner Carious Dentine Dental Caries
- bacterial invasion - minimal bacterial invasion
60 - unremineralizable - remineralizable
Knoop Hardness Number
- dead - alive
- without sensation - sensitive
50
40
30
transparant zone
20
10 zone of almost total zone of partial demineralization Sound Dentine
demineralization
E-D Junction 1000 2000 3000 µm
Crystals in Tubule Lumen
Peritubular dentine
Intertubular dentine
Bacteria
Odontoblast Process
20. Dental Caries
Two layers of carious dentine
Outer (‘infected’) Inner (‘affected’)
BacterialInvasion Few Bacterial
Unreminerizable Reminerizable
Dead Alive
Without sensation Sensitive
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21. Dental Caries
Remineralization of inner carious
dentine
Prerequisites physiological
remineralization:
Presence collagen fibers
Living odontoblastic process
External remineralization:
Saliva
, calcium and phosphate
Exposure bio-active agents
23. Dental Caries
Characteristics of occlusal caries
Fissure enamel and
1
dentine caries
2
3
4
24. Dental Caries
Characteristics of occlusal caries
Fissure cavity
1
2
3
4
3.6 mm
25. Dental Caries
Characteristics of occlusal caries
Lateral spread of fissure
1
cavity
2
3
4
3.6 mm
26. Dental Caries
Dentinal lesion formation and
progression: a summary
1 Enamel demineralization follows the
enamel rods.
2
Initial dentine demineralization does not
spread along the Enamel Dentine
Junction (EDJ) beyond the periphery of
the lesion in the enamel.
This leads to a cone shape lesion with
the base at the EDJ.
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27. Dental Caries
Dentinal lesion formation and
progression: a summary
1 In any pit and fissure system there can
be multiple lesions in different stages of
2
progression. (Stages A, B and C.)
Only when there is frank cavitation and a
cariogenic environment, will dentine
demineralization spread in a lateral
direction. (Stage D)
28. Dental Caries
Characteristics of approximal
caries
1. Subsurface demineralization of enamel.
1
2
3
4
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29. Dental Caries
Characteristics of approximal
caries
2. Partial demineralization of dentine directly
1
underneath enamel lesion
2
3
4
30. Dental Caries
Characteristics of approximal
caries
3. The dentine demineralization follows the
1
dentine tubules
2
3
4
31. Dental Caries
Characteristics of approximal
caries
4. Lateral spread of dentine caries occurs
1
mainly in cavitated lesions
2
3
4
32. Dental Caries
Characteristics of approximal
caries : a summary
Progression of approximal caries follows the
same principles as for occlusal caries.
It follows the enamel rods, but because of the
curved shape of the approximal tooth surface,
the lesion does not lead to a cone shape at the
EDJ as present in an occlusal fossa.
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33. Dental Caries
Traditional concepts of cavity
design
1
2
GV Black’s cavity preparations followed
3 designs that were largely dictated by the
4
physical properties of the filling materials
(e.g., amalgam and silicate cement).
These materials needed mechanical
retention
34. Dental Caries
Traditional concepts of cavity
design
1
2
Mechanical retention
3 Flatfloors
4
Vertical walls
Triangular retention
niches
Undercut areas
35. Dental Caries
Traditional concepts of cavity
design
1 Shape of the prepared cavity was not limited to
2
the tooth destruction caused by caries.
3
4
The preparation did not follow the way a dentine
lesion progresses.
Black's principles could be considered as: 'the
application of a mechanical design on a biological
process'
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36. Dental Caries
Traditional concepts of cavity
design
‘The application of a mechanical design on a
biological process'
1
2
3
4
37. Dental Caries
Longevity of amalgam
restorations
Research findings
survival time single surface: 10 – 8 years
survival time multiple surface: 8 - 6 years
Reasons for failures
secondarycaries
marginal breakdown
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39. Dental Caries
Repeat restoration cycle
‘Diagnoses’ are uncertain, with
1
considerable variation occurring
between dentists.
2
3
Extensive cavity preparations (Black) in
the name of outline form and extension
for prevention result in restorations with
weak margins, leading to marginal
breakdown and ‘ditching’.
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40. Dental Caries
Repeat restoration cycle
Dentists have an urge to replace restorations
1
2
Perceived (but erroneous) requirement to
3
‘freshen up’ the cavity walls and margins.
The teeth inevitably become weaker, thereby
reducing their prognosis.
The complexity of the restorations increases or
Tooth needs to be extracted.
41. Dental Caries
Traditional approach:
a Summary
1
2
Much sound tooth tissue needs to be
removed.
Traditionally placed restorations, on
average, do not last long.
The replacement restorations, in many
cases, last for less time.
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42. Dental Caries
Traditional approach:
a Summary
The end result is a tooth that became
1
weaker and weaker each time a
replacement was made.
2
The weaker the tooth becomes, the
more likely the restoration will fail,
resulting in a vicious cycle and termed
the ‘repeat restoration cycle’.
43. Dental Caries
Biological principals of cavity
preparation
1 Cavity cleaning
2 Obtaining access
Removal of dead dentine and enamel
Anatomy determines the shape
No preconceived cavity design
Black's principles are redundant
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45. Dental Caries
Appropriate instrumentation
Mechanical retention is no longer
1
needed with adhesive materials.
2
3
4
5
Shape of the cavity is determined by the
6
anatomy of the lesion.
7
8
46. Dental Caries
Appropriate instrumentation
Question:
1
2
3 Is a rotary instrument the best tool
4
5
when the cavity is determined by
6 the anatomy of the lesion ?
7
8
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47. Dental Caries
Appropriate instrumentation
1
NO !!!! A rotary instrument is not
2
the best instrument for:
3
4
5
removing only soft, completely
6
demineralized tooth tissue and
7
8 preserving as much as possible
remineralizable enamel and dentine.
50. Dental Caries
Appropriate instrumentation
Rotary instruments (only certain circumstances)
1
2
3 Slow speed drill
4 with straight bur for further opening of dentinal lesions
5
that have a very small entrance
6
with round bur for gentle removal of dead tissue.
7
8
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51. Dental Caries
Appropriate instrumentation
Rotary instruments (only certain circumstances)
1
2
3
High speed drill
4
onlyfor opening cavities that are inaccessible
5
6
removal of failed restorations.
7
8
52. Dental Caries
Appropriate instrumentation
Why hand instruments?
1
creates the most ideal (conservative) cavity
2
3 shape
4 gives the operator improved tactile sense
5
6
does not damage surfaces adjacent to the
7 lesion, in the case of approximal lesions and
8
therefore, does not promote caries
development.
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53. Dental Caries
Cavity restoration: WHY
To stop the caries process
To facilitate plaque removal
To encourage remineralization of inner
carious dentine
To restore function
To restore aesthetics.
54. Dental Caries
Cavity restoration: HOW
Application of a material that:
produces a seal against bacterial invasion
encourages remineralization
is sufficiently durable
maintains function.
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55. Dental Caries
Cavity restoration:
WHICH MATERIAL
Adhesive restorative materials
composite resins and polyacid-modified
composite resins (‘compomers’)
glass-ionomers and resin-modified glass-
ionomers.
Non-adhesive restorative materials
amalgam
58. Dental Caries
Tooth preservation versus
cavity preparation
1
2 For carious lesions in occlusal,
3
buccal and lingual surfaces of
4
posterior teeth:
Preventive resin restoration
Preventive glass-ionomer restoration
Atraumatic Restorative Treatment (ART )
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59. Dental Caries
Tooth preservation versus
cavity preparation
1
2 For carious lesions in approximal
3
surfaces of posterior teeth:
4
Box-type restorations (outcome: good).
Tunnel preparation (outcome: dubious).
ART (outcome: unknown yet).
60. Dental Caries
Effect of sealed versus non-
sealed restorations
Clinical trial in the USA.
more sound tooth structure was conserved
restoration margins were better protected
recurrent caries was less frequent
clinical survival of restorations was
prolonged.
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61. Dental Caries
Summary
1 The biological principle to the management of a
2
3
dentine lesion is to only remove soft, completely
4
demineralized tooth tissue. This is best achieved
through using hand instruments and/or a slowly
rotating drill rather than a high-speed drill. In doing
so, less sound tooth tissues are removed and
damage to surfaces of other teeth is minimized.
62. Dental Caries
Summary
1
Since only soft, completely
2 demineralized tissue is removed, there
3
can be no preconceived cavity design;
4
the anatomy of the carious lesion
dictates the size and shape of the cavity
preparation.
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63. Dental Caries
Summary
The treatment is completed by placing an
1
2
adhesive filling material into the cleaned cavity
3
preparation, over its margin, and over the
4 adjacent pits and fissures. This sealant
restoration will arrest caries activity that is
present in dentine and enamel, provided that
the bonding of the material to these tooth
tissues is adequately established.
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64. Dental Caries
Summary
1
This treatment modality has the potential
2 to:
3 control dentine caries
4
increase survival of the restoration
save tooth tissues and thus
increase tooth life expectancy.
65. Dental Caries
Remember:
TO APPLY PREVENTIVE MEASURES
TO ENCOURAGE ORAL HYGIENE AND
TO PROMOTE THE USE OF FLUORIDE
TOOTHPASTE.
66. Dental Caries
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