principles of cavity preparation

1. CAVITYPREPARATION
PRINCIPLES & PROCEDURES
Presentedby
CULEEN
BARAPON
PYRRHIC
CANCINO

2. CAVITY PREPARATION
“a surgical procedure that removes caries
and excises the tooth tissue in order to
develop the mortise form that will
support and retain the restorative
material”
“the orderly operating procedure required
to establish in a tooth the
biomechanically acceptable form
necessary to receive and retain a
restoration”

3. COMPONENTS
Cavity
Wall
one of theenclosing sides of a
prepared cavity
Axial
Wall
Wall near thepulp and parallel
to the long axis of thetooth
Pulpal
Wall
Wall near thepulp and
perpendicular to the long axis
of the tooth
Line
Angle
Angleformed bythe junctionof two
walls along a line
Cavo-
surface
Margin
Anglein a prepared cavity formed by thejunction
of the cavitywall and the external tooth surface
Point
Angle
Angleformed by thejunctionof three
walls at a commonpoint
Undercut
Portion of the prepared cavity
confined by walls that converge
toward the surface
Retention
Groove
A linearchannelwithin a
cavity preparation
DovetailA widened orfanned out portion of a
prepared cavity

4. THE PRINCIPLES
1
2
3
45
6
7
Outline Form
ResistanceForm
Retention Form
ConvenienceFormCaries Removal
Finish of the Cavity
Walls
Cavity Debridement

5. OUTLINE FORM
“The shapeof the area of the tooth surface INCLUDED WITHIN THE
CAVOSURFACEMARGINSof theprepared cavity”
“The locations that the PERIPHERIES of the completed tooth preparation
WILLOCCUPYontoothsurface”
“The PERIMETER of tooth preparation in width, length and depth
dimensions”

6. THE OUTLINE FORM
Factors to be considered
Areas to be Included
1. Access tothelesion
2. Extentofthe lesion
3. Extentofthe caries-
susceptible toothsurface
area
4. Locationandextentof
developmental grooves
5. Therestorativematerialto
beused
6. Estheticfactors
7. Functionalrequirements
ofthe restoration
1. Areaof thecariouslesion
2. The adjacentdeep, non-
coalesced enamel defects
3. All undermined,
unsupportedenamel

7. RESISTANCE FORM
“The shape given to the preparation that enables the restoration and the
remainingtoothstructure TOWITHSTANDMASTICATORY STRESS”
“The shape given to the preparation TO PREVENT FRACTURE of either
therestoration or toothduring insertion of thematerial orduring function”

8. THE RESISTANCE FORM
Prevent Fracture of
Restoration
Prevent Fracture of Tooth
1. Occlusal OutlineArea
- boxshape,flatfloors
2. CorrectTreatmentofLine
Angles –rounded
3. AdequateReductionfor
BulkandPins
4. CorrectCarving
1. Occlusal OutlineArea
2. Removed Undermined
Enamel
3. Removed Fragile Cusps
4. CorrectTreatmentofLine
Angles -rounded

9. RETENTION FORM
“The shape of the internal aspect of a prepared cavity to PREVENT
DISPLACEMENT OF THE RESTORATIVEMATERIAL”
“The form given to the tooth preparation, especially its detailed anatomy
and general shape, which enables the restoration, that it will accomodate,
TOAVOID BEINGDISLODGED BYMASTICATORYLOADING”

10. THE RETENTIONFORM
Auxiliary MeansPrincipal Means
1. Grooves
2. Internalboxes
3. Posts
4. Pins
5. Triangularareas
6. Etchingor acid
conditioning
7. Cement
1. FrictionalRetention
2. Elasticdeformationof
dentin
3. Inverted truncatedcones
orundercuts
4. Dovetail

11. CONVENIENCE FORM
“The shape or form of the cavity that ALLOWS ADEQUATE VISION,
ACCESSIBILITY, AND EASE OF INSTRUMENTATIONduring cavity
preparation as well asinsertion oftherestorative material”
“That shape given to a tooth preparation or tooth modifications added to
the preparation or its instrumentation, which ENABLES THE
RESTORATIONTOBE COMPLETED CONVENIENTLY”

12. THE CONVENIENCE FORM
Other Modes to Obtain
ConvenienceForm
1. Modificationsin tooth
preparation
2. Instrumentmodification
3. Separation
Ideally, a tooth preparation fulfilling all the requirements for
outline, resistance, and retention forms will be convenient to
instrumentation.
The most effective way is by proper control of the field of
operation and by adequate training and familiarity with the
armamentarium

13. CARIESREMOVAL
“The MECHANICAL ELIMINATION OF CARIOUS DENTIN AND
DEBRISfromcavitypreparations”
“The mechanical and/or chemical actions resulting in COMPLETE
ELIMINATION OF THE DISEASED, NONREPARABLE PORTIONS
OF DENTIN”

14. CARIES REMOVAL
Removal of Caries
Acutecaries–using the
broadestdiscoid/spoon
excavator
Chroniccaries–using large
roundbur preferablydull
REMOVAL OF DENTIN DEPENDS ON
TWO CONDITION:
AFFECTED DENTIN
• doesnotcontain
microorganism
•canberemineralizedby
restorativemeans
•it isacceptedtoallow
affecteddentin toremain
in preparedtooth
INFECTEDDENTIN
• containsmicroorganism
•cannotberemineralized
byrestorativemeans
•it shouldberemoved
duringcavity preparation

15. FINISH OF THECAVITY
WALL
“Involves REFINING OF CERTAIN AREAS OF THE CAVITY WALL: the dentin
portion, theenamelportion andthecavosurfacemargin”
“The ‘CONFIGURATION’ OF THE ENAMEL WALLS is the shape, dimension,
location,andangulationof enamelcomponentsin afinaltoothpreparation”
“To PROVIDE THE BEST POSSIBLE MARGINAL SEAL AND MAXIMUM
STRENGTHtoboththetoothandtherestorative material”

16. Enamelwallmustrest uponsound dentin
FINISH OF THE CAVITY
WALL
Theenamel rodswhichform thecavosurface
anglemusthavetheir inner ends resting
on sounddentin
Therods whichform thecavosurfaceanglemustbe supported, or be
resting, onsound dentinandtheir outer ends mustbecovered by
therestorative material
Thecavosurfaceangle mustbeso trimmedor bevelled that
themarginswill not beexposed to injury incondensing the
restorative material againstit

17. CAVITY DEBRIDEMENT
“Final step involving the use of explorer, air and water spray, and cotton
pellets toREMOVE DEBRIS FROMTHECAVITYPREPARATION”
“It consists of FREEING ALL ANGLES AND SURFACES OF DEBRIS
andoftenincludes medicationandinsulationprocedures.

18. 1. Freeing ofall preparationwalls,
floorsandmargins fromenamel
anddentinchips
2. Dryingthe preparationwalls,
floorsandmargins
3. Sterilizationof preparationwalls
andfloors.
CAVITY DEBRIDEMENT
Objectives
Water, air,or combinationsof air-water
jets
Drycottonpellets
Cavitycleaners
Scrapingwalls,floors andmargins
Using preparation disinfectant
Using 10%EDTASolution M

19. FOR AMALGAM
CAVITYPREPARATIONs