•By Dr-Nashwan Mohammed
M.Sc , BDS.
Lack of understanding of the
caries process in particular the
potential for re-mineralization.
The poor physical properties of
available restorative materials.
Black’s principles of extension
Sacrifice sound enamel
and dentin to place cavity
margins into self
cleansing areas or caries
Dictate the extension of
fissures to allow cavosurface margins to
terminate on non-fissured
The resistance and
retention form required to
prevent amalgam failures.
Implementing through :
Caries risk assessment
Prevention and remineralization of non
Consequences of Black’s
principle of extension for
Gross weakening of the
Structural and marginal
failure of the restoration.
Increased potential to
will maximize the chemical , electrical,
thermal, bacterial, osmotic and
Increased gingival and
roughness and plaque accumulation)
More time money and
Difficult maintenance of
the restorative system.
In the past decades , conservatism
was just targeting the minimization
of tooth structure cutting whereas
in the modern conservative theory
there’s an intention to use a
medical model and avoid cutting if
possible. this would require the
detection and discovery of the
lesion in its subclinical stage
before it initiates any defect that
would need repair.
Adoption of medical
model would save
money , effort and time
Preventing the development of
defects or new cavities.
Preventing periodontal problems.
Stopping the progress of existing
lesions and decay spots.
Maintaining existing old
It focuses on a minimal invasive
dentistry or preservative dentistry,
which allows a shift from the
traditional surgical approach to a
control of defects without cutting or
if cutting is to be done it has to be
restricted as much as possible.
Control of causative factor or
cariogenicity to eliminate further
Remineralization of early lesions.
Minimal surgical intervention for
Repair rather than replace for
Essentials to allow
The tools used.
The restorative materials.
The oral environment conditions.
The socioeconomic conditions of
Major role is played by the clinician
performing the job.
Knowledge and understanding of
the defect ,demineralization / remineralization cycle.
Treating the disease by allowing
re-mineralization to occur more
than demineralization. (saturation of
saliva with fluoride, calcium and phosphates to
drive them inside the tooth thus enhancing remineralization)
The tools used
Advanced diagnostic tools to
detect incipient lesions:
The intraoral camera.
Laser based device.
The high resolution
transilluminator (Digital imaging
fiber optic transillumination tool
Electrical caries monitor (ECM).
Ideal Cutting Instrument
Ease of use.
Discriminate and remove diseased
Required minimal pressure.
No heat generation or vibration.
Minimal or non-invasive cutting
Air abrasion technology.
Chemo-mechanical removal of
Adhesion is thus different from
micromechanical bonding which
relies for retention and sealing on
an intermediary joint consisting of
a system of numerous resin
microtags and resin tooth hybrid
created in the top 2-5 лm layer of
It seems essential to substitute the term
adhesion by Bododontics to be more
precise in description of this science.
Bonding allow maximum preservation of
tooth structure and hence maximum
The cavities to be cut should be
complying with the properties of
the different restorative materials.
These properties thus impose
certain depth , width , wall’s
inclination and finishing of
Selection of materials that would
achieve conservatism becomes
imperative and therefore there’s a
marked trend to shift to direct tooth
colored restoratives rather than
metallic and indirect restoratives.
The oral environment
Salivary flow and pH. Resting flow
rate range between 0.3-0.4ml/min
while stimulated flow rate has an
average rate between 1-2ml/min.
Buffering effect of saliva
Oral microbes , chemical
degradation potentials ,
masticatory forces and chewing
conditions of the patient
Privileged , educated , employed
regular dental check
low caries risk
for conservative approach.
The opposite individuals would
require much more radical
Certain data have
to be collected
prior to decision
making about the
To Drill or not to Drill ?
Or when to Prepare a
Caries risk evaluation
Estimation of food cariogenicity.
Frequency of intake of meals and
Patient motivation for adopting
Failures are faced due to the
difficulty of convincing the patient
to change their dietary habits.
Caries risk assessment
It is based on the fact that for
caries to develop , there are
several factors that should be
present to contribute to its
occurance. By modifying the factor
that play the major , this could
successfully prevent the
development of the disease.
Caries risk assessment
This done to
If an individual
A certain time
Amount of plaque.
Type of bacteria.
Type of diet.
Salivary buffering capacity.
Amounts of fluoride ingested.
Patient’s general health.
According to this caries risk
assessment the patient could be
Allow identification of the defect
and correlation of previously gather
data with the clinical picture. Upon
diagnosis , the defect should be
classified as carious or non-carious
and dealt with accordingly.
Biological or medical
model of treatment
This model deals with caries as a
disease that should be treated
prior to any restorative procedures
Diet and habits modification.
Salivary flow and buffering capacity adjustment.
Mechanical preventive measures ( calculus and Biofilm control)
to fit into a dental office preventive Program.
Use of antimicrobials to fit into a home care preventive
Remineralization of initial lesions.
Fissure sealing for susceptible sites.
Close follow up to monitor the healing procedure.
Perform minimal intervention and prevention for diseased tissues
that can’t be remineralized and restore them conservatively.
Surgical Model of
The diseased tissues are beyond
healing and couldn’t be
Drilling and cutting away the
diseased tissue without giving
attention to the MO as a causative
Cavity is prepared minimally with
maximum preservation of tooth
strength and anatomy followed by
its restoration for maximum
Features of a
Include all defective enamel and
No extension beyond defective
Convenient instrumentation and
Freeing of all margins with
Necessary resistance and
Black’s versus Mount
Black’s classification doesn’t
specify the size of the lesion.
Mount and Hume classified the
lesion based on site and size
Extension for prevention concept
Obtaining the resistance form
Removal of remaining carious dentin
Conservative cavity design
According to Black
According to conservatism
Caries and convenience dictate the
Removal of all pits and fissures.
Only carious fissures.
Mesially and distally extended midway
between the marginal ridge and depth of
the triangular fossa.
Shallow fissures can be treated by
enameloplasty or slanting bur technique.
Extended midway between axial line
angle and facial or lingual margin of
The gingival margin extends below the
crest of the healthy gum margin.
Pit and fissure sealant when there is a
Facial and lingual margins extend just
beyond the contact area to free it. With a
clearance of 0.5mm.
The gingival margin extends just to
Facial and lingual surfaces all margins
are dictated by the outline of the defect.
Obtaining the resistance and
Cavity width is governed
by margin placement
midway between the cusp
tip and depth of the
Depth almost 0.5mm
pulpual to DEJ.
Retention mainly through
Cavity width to be
extended to provide
Cavity could be in dentin
or in enamel.
Removal of Remaining Carious
All caries must be
removed , if pulp exposed
then do Endo.
There could be
irreparable damage by
bacterial invasion so
every trace of carious
dentin should be
affected and infected
dentin (Caries detector
caries removal (Carisolv)
Smartprep burs , Polymer
Based on the shape and extent of
the lesion. No flat floors nor
squaring of the cavity. But with
refinements to satisfy certain
Ginival crevice are not immune
from caries.(Subgingival Margins)