Dentine caries /certified fixed orthodontic courses by Indian dental academy

DENTINE CARIES
PROGRESSION AND
HOW TO STOP IT

INDIAN DENTAL ACADEMY
Leader in Continuing Dental Education
www.indiandentalacademy.com

Dental Caries

Sugar and plaque, the arch
criminals of dental caries

Dental Caries

Demineralization, remineralization

Sugar + Dental Plaque
ACID
S
Demineralization
Cavities

Dental Caries


Subsurface
demineralization of
enamel

Dental Caries


Occlusal lesions can
be arrested by
remineralization

Dental Caries


recently cleaned front teeth
with signs of demineralization
and gingivitis

after some weeks
remineralization has taken
place and the gingivitis is
healed

Dental Caries


No sugar before
sleeping

Dental Caries

The Caries Balance

Resistance
 Plaque removal
 Sugar reduction
 Fluoride
 Sealants
 Chlorhexidine

Dental Caries

Structure of dentine

 Living tissue
 Peritubular dentine
 Intertubular dentine
 Apatite crystals
 Intermolecular cross-linking

Dental Caries

Dentine Structure

Dental Caries

Progression of dentine caries
Bacterial Invasion
1

2

3

4

5

6

7

8

Dental 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.

Dental Caries

Crystal Removal Process
1

2

3

4

5

6

7

8

Dental 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

Dental 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

Dental Caries

Defense reaction in dentine
1

2

3

4

5

6

7

8

Dental 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

Dental 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.

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

Dental Caries

Two layers of carious dentine

Outer (‘infected’) Inner (‘affected’)
 BacterialInvasion  Few Bacterial
 Unreminerizable  Reminerizable
 Dead  Alive
 Without sensation  Sensitive

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

Dental Caries

Characteristics of occlusal caries

Fissure enamel caries
1

2

3

4

Dental Caries


Fissure enamel and
1
dentine caries
2

3

4

Dental Caries


Fissure cavity
1

2

3

4

3.6 mm

Dental Caries


Lateral spread of fissure
1
cavity
2

3

4

3.6 mm

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.

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)

Dental Caries

Characteristics of approximal
caries
1. Subsurface demineralization of enamel.
1

2

3

4

Dental Caries

caries
2. Partial demineralization of dentine directly
1
underneath enamel lesion
2

3

4

Dental Caries

caries
3. The dentine demineralization follows the
1
dentine tubules
2

3

4

Dental Caries

caries
4. Lateral spread of dentine caries occurs
1
mainly in cavitated lesions
2

3

4

Dental Caries

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.

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

Dental Caries

design
1

2
Mechanical retention
3  Flatfloors
4
 Vertical walls
 Triangular retention
niches
 Undercut areas

Dental Caries

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'

Dental Caries

design
‘The application of a mechanical design on a
biological process'
1

2

3

4

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

Dental Caries

Repeat restoration cycle

1

2
3  Occlusal lesion and occlusal restoration
 2-Surface restoration
 Extended restoration
 Crown or Extraction

Dental Caries

 ‘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’.

Dental Caries

 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.

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.

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’.

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

Dental Caries

Biological principals of cavity
preparation
1

2

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

Dental Caries

 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

Dental Caries


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.

Dental Caries

 Hand instrument:
1
 Dental hatchet
2

3

4

5

6

7

8

(e.g., 10 – 6 - 12)

Dental Caries

 Hand instrument:
1
 Excavator
2

3

4

5

6

7

8

(e.g., 153 – 154)

Dental Caries

 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

Dental Caries

 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

Dental Caries

 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.

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.

Dental Caries

Cavity restoration: HOW

 Application of a material that:
 produces a seal against bacterial invasion
 encourages remineralization
 is sufficiently durable
 maintains function.

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

Dental Caries

Tooth preservation versus
cavity preparation
1

2

3

4 Preservation =
restoration + prevention

Dental Caries

cavity preparation
1

2

3

4

Sealant
restorations

Dental Caries

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 )

Dental Caries

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).

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.

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.

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.

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.

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.

Dental Caries

 Remember:
 TO APPLY PREVENTIVE MEASURES

 TO ENCOURAGE ORAL HYGIENE AND

 TO PROMOTE THE USE OF FLUORIDE
TOOTHPASTE.

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