Principles of tooth preparation

principles of tooth preparation with descriptive pictures in a lucid style.

1. PRINCIPLES OF TOOTH
PREPARATION
Dr.RAKESHR NAIR
PG STUDENT
DEPT.OF CONS & ENDO
KVG DC ,SULLIA

2. •Tooth preparation may be defined as the mechanical treatment of dental
disease or injury to hard tissue that restores a tooth to the original form
(Tylman).
•The mechanical preparation or the chemical treatment of the remaining
tooth structure, which enables it to accommodate a restorative material
without incurring mechanical or biological failure.(Marzouk)

3. •Thecurrentfocusisonconservativetoothpreparationthatis
noninvasiveandthatminimallyinvolvesdentin.
•Thistrendisrationalinthelightofthereductionofthecariesrate
byfluorides,nutritionalcounselingandoralhygieneprograms.
Black’sprinciplesofcavitypreparationandTylman’sprinciplesof
toothpreparationarebothpresentlybeingmodifiedto
accommodateimaginativeapproachesi.e.,acidetchingwith
minimumreduction.
•Dentistryischangingfrommacrotoothpreparationtoan
environmentofmolecularchemistryi.e.,estheticbonding.These
techniquesarenotpresentlysupportedbyanylongitudinal
studies,butareexcitingandpromising.

4. Despite these advances, traditional
crowns are still indicated for
majority of patients. The classic
design of the preparation must be
visualized so that modifications if
required can be instituted.
Diagnosis and disciplined tooth
preparation are essential to
successful fixed prosthetics.

5. OBJECTIVES OF TOOTH PREPARATION
Theobjectivesofpreparationremainclearlydefined,but
themethodsofsecuringthesegoalsareconstantlybeing
revised.
1.Reductionofthetoothinminiaturetoprovide
retention.
2.Preservationofhealthytoothstructureto
secureresistanceform.
3.Provisionforacceptablefinishline.
4.Performingpragmaticaxialtoothreductionto
encouragefavorabletissueresponsesfrom
artificialcrowncontour.

6. BIOLOGIC
Conservation of tooth
structure
Avoidance of over
contouring
Supra gingival margins
Harmonious occlusion
Protection against tooth
fracture
MECHANICAL
Retention form
Resistance form
ESTHETIC
Minimum display of
metal
Maximum thickness of
porcelain
Porcelain occlusal
surfaces
Subgingivalmargins
PRINCIPLES OF TOOTH PREPARATION
(According to Rosenstiel)
Optimal restoration

7. Damage to adjacent teeth is prevented by positioning the
diamond so a thin lip of enamel is retained between the bur
and the adjacent tooth.
Note that the orientation of the diamond parallels the long axis.
The enamel should be maintained mesial to the path of the diamond as the
reduction progresses.

8. Soft tissues
Damage to the soft tissues of the tongue and cheeks
can be prevented by careful retraction with an aspirator
tip, mouth mirror , or flanged salivaejector.
Great care is needed to protect the tongue
when the lingual surfaces of mandibular molars are
being prepared.

9. Pulp
Great care also is needed to prevent pulpal injuries
during fixed prosthodonticprocedures,
Especiallycomplete crown preparation.
Pulpal degenerationthat occurs many years after tooth preparation has
been documented.
Extreme temperatures, chemical irritation, or microorganisms can cause an
irreversible pulpitis particularly when they occur on
freshly sectioned dentinal tubules.

10. •Temperature
•Chemical action
•Bacterial action

11. PRINCIPLES OF TOOTH PREPARATION
AccordingtoShillingburg,thedesignofa
preparationforacastrestorationsandtheexecutionof
thatdesignaregovernedbyfiveprinciples:
1.Preservationoftoothstructure
2.Retentionandresistance
3.Structuraldurability
4.Marginalintegrity
5.Preservationoftheperiodontium.

12. Preservation of Tooth Structure
•Inadditiontoreplacinglosttoothstructure,arestorationmust
preserveremainingtoothstructure.
•Intactsurfacesoftoothstructurethatcanbemaintainedwhile
producingastrong,retentiverestorationshouldbesavedifpatient
acceptanceandretentionrequirementswillpermitit.
•Preservationoftoothstructureinsomecasesmay
requirethatlimitedamountsofsoundtoothstructurebe
removedtopreventsubsequentuncontrolledlossoflarger
quantitiesoftoothstructure.

13. Thisistherationalefortheremovalof1to1.5mmofocclusal
toothstructurewhenpreparingatoothforanMODonlay.
Themetalontheocclusalsurfacecanprotectagainstdramatic
failures,
suchasfractureoftoothstructure,aswellasthelessobvious
failuresthatmaybeoccasionedbytheflexingoftoothstructure

14. Conservation of tooth structure by using partial-coverage restorations. In this
case, they are used as fixed dental prosthetic abutments to replace congenitally
missing lateral incisors.

15. Retention and Resistance
•No cements that are compatible with living tooth
structure and the biologic environment of the oral cavity
possess adequate adhesive properties to hold a
restoration in place solely through
adhesion.(Shillingburg)
•The geometric configuration of the tooth preparation
must place the cement in compression to provide the
necessary retention and resistance.

16. Retentionprevents removal of the restoration along the
path of insertion or long axis of the tooth preparation.
Resistanceprevents dislodgment of the restoration by
forces directed in an apical or oblique direction and prevents
any movement of the restoration under occlusal forces.
Retention and resistance are interrelated and often inseparable
qualities.
The essential element of retention is two opposing vertical
surfaces in the same preparation.

17. Taper
The axial walls of the preparation must taper slightly to permit the
restoration to seat; ie,
two opposing external walls must gradually converge or
two opposing internal surfaces of tooth structure must
diverge occlusally.
The terms angle of convergence and angle of divergence can be used to
describe the respective relationships between the two opposing walls of
a preparation.
The relationship of one wall of a preparation to the long
axis of that preparation is the inclinationof that wall.

18. •A tapered diamond or bur will impart an inclination of 2 to 3 degrees to any
surface it cuts if the shank of the instrument is held parallel to the intended
path of insertion of the preparation.
•Two opposing surfaces, each with a 3-degree inclination, would give the
preparation a 6-degree taper.

19. Prothero(1923)indicatedthatconvergenceofperipheralsurfacesshould
rangefrom2
0
-5
0
.
Jorgensen(1955)foundthatretentiondecreasesasthetaperincreases.A
rangeof2-6.5
0
hasbeenconsideredtobeoptimal.Hetestedtheretentionof
crownsatvariousanglesbyapplyingatensileforceoncementedcrown.
Maximumstrengthwasobtainedat5
0
.
Mack(1980)estimatedthataminimumtaperof12
0
isnecessaryjustto
ensuretheabsenceofundercuts.Thetendencytoovertaperpreparations
mustbeavoidedinordertoachievemaximumretention.
Ebnashi(1969)tominimizestressinthecementinterfacebetweenthe
preparationandrestoration,ataperof2.5to6.5
0
hasbeensuggested
optimum,butthereisonlyaslightincreaseinstressastaperisincreasedfrom
0to15
0
.Howeverat20
0
stressconcentrationwasfoundtoincreasesharply.

20. •Consciously attempting to cut a taper can easilyresult in an
overtaperedand nonretentivepreparation.
•Ataper or total convergence of 16 degrees has been proposed
as being achievable clinically while still affordingadequate
retention.
•This is probably an acceptableoverall target. It can be as low as
10 degrees on preparationson anterior teeth and as high as 22
degrees onmolars.

21. Freedom of Displacement
Maximum retention is achieved when there is only one path.
A full veneer preparation with long, parallel axial walls and grooves would
produce such retention .
On the opposite extreme, a short, overtaperedpreparation would be
without retention because the restoration could be removed along an
infinite number of paths.
Limiting the freedom of displacement from torquingor twisting forces in a
horizontal plane increases the resistance of a restoration.
A groove whose walls meet the axial wall at an oblique angle does not
provide the necessary resistance. V-shaped grooves produce roughly one-
half as much resistance to lingual displacement as do grooves with a
definite lingual wall.

23. Surface area :
Greater the area of the cement film bound to the preparation and to the
internal detail of the casting, greater the retention.
The total surface area of the preparation is influenced by the size of the tooth,
the extent of the coverage by the restoration, and internal features such as
grooves and boxes

24. Area under shear:
Most important for retention is the
area of cement that will experience
shearing rather than tensile stress.
For the shear strength of the cement
to be utilized, the preparation must
have the opposing walls nearly
parallel with each other.
The direction in which a restoration
can be removed must be limited to
one path. A severely over tapered
preparation has many paths along
which tensile force could remove a
crown.

25. Types of preparation :
Differenttypesofpreparationshavedifferentretentivevalues
andthesecorrespondfairlycloselytothesurfaceareaoftheaxial
walls,providedotherfactors(e.g.taper)arekeptconstant.Thusthe
retentionoffullveneercrownsarealmostdoublethatofpartial
coveragerestorations.
Addinggroovesorboxestoapreparationwithalimitedpathof
withdrawaldoesnotmarkedlyaffectitsretentionbecausethesurface
areaisnotincreasedsignificantly(Rosenstiel).Howeverotherauthors
havereportedthat,wheretheadditionofgroovesorboxeslimitsthe
pathofwithdrawal,retentionisincreased.

26. For the grooves to be effective, the
lingual wall of the groove must be
distinct and perpendicular to adjoining
axial wall
The walls of a groove that meet the
axial wall at an oblique angle do not
provide necessary resistance (A). The
walls of a groove must be
perpendicular to rotating forces to
resist displacement (B).

27. Length of the preparation is important
factor in retention
Longer preparation has a greater
retention than does a short
preparation, due to greater surface
area.
The preparation with longer walls
interferes with the tipping
displacement of the restoration better
than the short preparation. Because
of greater surface area preparation
with larger diameter will have greater
retention than with narrow
preparation of same length

28. Surface roughness:
The adhesion of the dental
cements primarily depends on
microscopic irregularities and the
recesses on the surfaces being
joined the prepared tooth
surface should not be highly
polished

29. Resistance:
Resistance prevents dislodgement of restoration by forces
directed in the apical or oblique direction
Resistance to sliding or tipping must be designed into the
preparation
Leverage And Resistance:
Leverage, is the predominant factor in the dislodgement of
the cemented restoration, occur when line of action of
force passes outside the supporting tooth structure.
Length of preparation has strong influence on its resistance
Shortening a preparation will produce a proportionally
greater diminution of the resisting area

30. A short restoration on a short
preparation is less likely to fail
through tipping than is a long
restoration on same preparation as
the force on it acts through a longer
lever arm.
A preparation on a tooth with a
smaller diameter resists pivoting
movements better than a preparation
of equal length on a tooth of larger
diameter because smaller teeth will
have a short rotational radius for the
arc of displacement and the incisal
portion of the axial wall will resist
displacement

31. When relatively long crown must be
made on a short preparation
additional resistance form, in form of
pin retained core must be created.
Resistance and Tooth Width
A wider preparation has greater
retention than narrower one of equal
height. Under some circumstances a
crown on the narrow tooth can have
greater resistance to tipping than one
on wider tooth. This is because crown
on narrower tooth has a shorter
radius of rotation resulting in larger
resisting area
Resistance of a preparation on a
short, wide tooth can be enhanced by
addition of grooves

32. •The path of insertion is an imaginary line along which the
•restoration will be placed onto or removed from the
•preparation.
•It is determined mentally by the dentist
•before the preparation is begun, and all features of the
•preparation are cut to coincide with that line.
Path of insertion

33. If the center of the occlusal surface of a preparation
is viewed with one eye from a distance of approximately
30 cm (12 inches), it is possible to sigh! down the
axial walls of a preparation with a minimum taper

34. For a preparation to be surveyed in the mouth, where
direct vision is rarely possible, a mouth mirror is used.
It is held at an angle approximately 1/2 inch above the preparation, and
the image is viewed with one eye.
If fixed partial denture abutment preparations are
being evaluated for a common path of insertion, a firm
finger rest is established and the mirror is maneuvered
until one preparation is centered.
Then, pivoting on the finger rest, the mirror is moved, without
changing its angulation, until it is centered over the second preparation

35. Structural Durability
•Arestorationmustcontainabulkofmaterialthatisadequateto
withstandtheforcesofocclusion.
•Thisbulkmustbeconfinedtothespacecreatedbythetooth
preparation.
•Onlyinthiswaycantheocclusionontherestorationbeharmonious
andtheaxialcontoursnormal,preventingperiodontalproblems
aroundtherestoration
•Therearethreepreparationfeaturesthatcontributetothedurability
oftherestorationthatis(1)Occlusalreduction(2)axialreduction(
3)provisionforreinforcingstruts

36. Occlusal Reduction
One of the most important features for providing adequate
bulk of metal and strength to the restoration is OcclusalClearance.
For gold alloys, there should be 1.5 mm of clearance on the functional
cusps (lingual of maxillary molars and premolars and buccalof
mandibular molars and premolars)

37. •Metal-ceramic crowns will require 1.5 to 2.0 mm on
functional cusps that will be veneered with porcelain and
•1.0 to 1.5 mm on nonfunctional cusps to receive ceramic
coverage.
•There should be 2.0 mm of clearance on preparations for all-
ceramic crowns.
•Malposedteeth may have occlusal surfaces that are not
parallel with the occlusaltable. Therefore, it may not be
necessary to reduce the occlusal surface by 1.0 mm to achieve
1.0 mm of clearance.

38. The basic inclined plane pattern of the occlusal
surface
should be duplicated to produce adequate
clearance
without overshorteningthe preparation

39. Functional Cusp Bevel
An integral part of the occlusal reduction is the functional
cusp bevel . A wide bevel on the lingual
inclines of the maxillary lingual cusps and the buccal
inclines of mandibular buccalcusps provides space for
an adequate bulk of metal in an area of heavy occlusal
contact.
If a wide bevel is not placed on the functional cusp,
several problems may occur

40. To prevent a thin casting
when there is no functional cusp bevel, an attempt may
be made to wax the crown iooptimal thickness in this
area. An overcontouredrestoration will result and a
deflective occlusal contact is likely to occur unless the
opposing tooth is reduced

41. Axial reduction:
Second prerequisite for structural durability is axial reduction.
When it is sufficient, restoration walls have satisfactory
thicknesses with out over contouring
Reinforcing struts: the features that serve to provide space for the
metal that will improve the durability and the rigidity of the
restoration: Offset the occlusal shoulder, the isthmus, the proximal
grooves, and the box. Isthmus connects the boxes, and the offset
ties the grooves together to enhance the reinforcing “truss effect”.

42. Marginal Integrity
The restoration can survive in the biological environment
of the oral cavity only if the margins are closely adapted
to the cavosurfacefinish line of the preparation. The
configuration
of the preparation finish line dictates the shape
and bulk of restorative material in the margin of the
restoration It also can affect both marginal adaptation
and the degree of seating of the restoration

43. FINISH LINE REQUIREMENTS
Definition:
The point at which a preparation terminates on the
tooth is called the finish line. It is also defined as the
peripheral extension of a tooth preparation (GPT).

44. There are three requirements for successful restoration margins.
Fundamentals of tooth preparation:Shillingburg,Jacobi,Bracket

45. Functions:
Thefinishlineservesthefollowingfunctions:
•Duringvisualevaluationofthetoothpreparation,itis
ameasureoftheamountoftoothstructurealready
removed.Italsodelineatestheextentofthecutinan
apicaldirection.Themoredistinctitis,thebetterit
servesthesepurposes.
•Thefinishlineisoneofthefeaturesthatcanbeused
toevaluatetheaccuracyoftheimpressionmadefor
indirectprocedures.
•Inthedie,adistinctfinishlinehelpstoevaluatethe
qualityofthedieandhelpsinaccuratedietrimming.
•Thecorrectmarginaladaptationofthewaxpattern
dependsonanobviousfinishline.
•Theevaluationoftherestorationisalsoaidedbya
properfinishline.
•Atcementation,asharpfinishlineaidsin
determiningwhethertherestorationisfullyseated.

46. •Historically a bevel was introduced to compensate for the casting shrinkage
of alloys used to fabricate crowns.
•Metal margins should be ideally acute in cross section rather than right-
angled to facilitate a closer fit.
•Dis the distance by which the crown fails to seat
•dis the shortest distance between the tooth structure and the restoration
•If the inner angle of the metal margin forms an angle m ,of less than 90
degrees with the path of insertion ,as does a bevel or a chamfer ,dwill be
smaller than D.
•The shortest distance from the casting margin to tooth structure ,d, can
be stated as a function of Dand the sine of the angle m or the cosine of
the angle p,whichis the angle between the surface of the bevel and the
path of insertion.

48. d = D sin m
or
d = D cosp
As the angle m is reduced its sine value also reduces and so does
the value of d…thus reducing the marginal discrepancy.

49. An angle of 30 to 45 degrees is considered optimal
•Angles above 50 degrees will not reduce the value of d.
•Angles below 45 degrees will result in too thin a casting.

50. TYPES OF FINISH LINES
Chamferfinishline:
Thepreferredfinishlinefortheveneermetal
restorationsisthechamfer.Thisfinishlinehasbeen
shownexperimentallytoexhibittheleaststress,sothat
thecementunderlyingitwilllesslikelihoodoffailure.It
canbecutwiththetipofaroundenddiamond,whilethe
axialreductionisbeingdonewiththesideofthat
instrument.However,atorpedodiamondislesslikelyto
produceabuttjoint.Themarginofthecastrestoration
thatfitsagainstitcombinesanacuteedgewithanearby
bulkofmetal.

51. Heavychamferfinishline:
Aheavychamferisusedtoprovidea
90-degreecavosurfaceanglewithalargeradius
roundedinternalangle.Itiscreatedwitha
roundendtapereddiamond.Inthehandsofan
unskilledoperator,thisinstrumentcancreatean
undesirablefragilelipofenamelatthe
cavosurface.Theheavychamferprovidesbetter
supportforaceramiccrownthandoesa
conventionalchamfer,butitisasgoodasa
shoulder.Abevelcanbeaddedtotheheavy
chamferforusewithametalceramic
restoration.

52. Shoulder:
Theshoulderhaslongbeenthefinish
lineofchoicefortheall-ceramiccrowns.The
wideledgeprovidesresistancetoocclusal
forcesandminimizesstressesthatmightleadto
fractureoftheporcelain.Itproducesthespace
forhealthyrestorationcontoursandmaximum
esthetics.However,itdoesrequiredestruction
ofmoretoothstructurethananyotherfinish
line,thesharp90-degreeinternallineangle
associatedwiththeclassicvarietyofthisfinish
lineconcentratesstressinthetoothandis
conductivetocoronalfracture.Theshoulder
generallyisnotusedasafinishlineforcast
metalrestorations.

53. Shoulderwithbevel:
Theshoulderwithabevelisausedasa
finishlineinavarietyofsituations.Itisutilized
asthegingivalfinishlineontheproximalbox
ofinlaysandonlays,andfortheocclusal
shoulderofonlaysandmandibularthreequarter
crowns.Thisdesigncanalsobeusedforthe
facialfinishlineofmetalceramicrestorations
wheregingivalestheticsisnotcritical.Itcanbe
usedinthosesituationswhereashoulderis
alreadypresent,eitherbecauseofdestructionby
cariesorthepresenceofpreviousrestorations.
Itisalsoagoodfinishlineforpreparationswith
extremelyshortwalls,sinceitfacilitiesaxial
wallsthatarenearlyparallel.

54. Knife-edge:
Theknife-edgemarginprovidesforan
acutemarginofmetal.Butitsusecancreate
problems.Unlessitiscarefullyprepared,the
axialreductionmayfadeoutinsteadof
terminatinginadefinitefinishline.Thethin
marginoftherestorationthatfitsthisfinishline
maybedifficulttoaccuratelywaxandcast.Itis
alsomoresusceptibletodistortioninthemouth
whenthecasingissubjecttoocclusalforces.

55. Featheredge:
Afeatheredgefinishlineisunacceptable
becauseitisnotsufficientlydistinctandresults
insolittlecervicaltoothreductionthatthe
restorationmustbeovercontouredtopossess
adequaterigidity.Also,sinceafeatheredgeis
moredifficulttoseevisually,occlusocervical
undulationsandirregularitiesinthefinishline
aremorelikelytobepresent,makingitmuch
moredifficulttofabricatearestorationthatfits
accurately.

56. Instrumentation
The advent of hand piece capable of speeds in excess of 100,000 rpm made possible
efficient cutting with smaller instruments,whichmade more sophisticated preparations
practical.
With high speed instruments the problem of over heating the tooth during preparation
is critical.
Cutting dry can cause three times more dentinal burning and thermal changes leading
to pulpal inflammation and necrosis than with adequate air water spray.
Brown et` al calculated the temperature of high speed dry cutting to be 118 degree
celcius.
The seriousness of which can be understood from Zach`s contentions that even an
increase of 20 degree Fahrenheit will lead to pulpal death in 60% of the teeth.
Dry cutting of non-vital teeth also should be avoided as it can lead to micro fractures in
the enamel.

57. There are basically three main rotary instruments used in tooth preparation.
1.Diamond stone
2.Tungsten carbide bur
3.Twist drill

58. Diamond stones
Numerous small ,irregularly placed sharp diamond chips are
electroplated with a nickel or chromium bonding medium to
steel instrument blanks whose head is machined to the
desired final shape of the instrument.
They most effective against cutting enamel and porcelain.
An ideal diamond instrument should have diamond stones
evenly placed with intimate contact between the chips and
the binding material.

62. Tunstencarbide burs
They are best suited for making precise preparation
features and smooth surfaces on enamel and dentin.
They can also be used to cut metal.
The metal in the head of the tungsten carbide bur is
formed by sintering tungsten carbide powder and cobalt
powder under heat and vacuum.
These are then cut into desired lengths and attached to
steel rods using soldering or welding.
Most burs have six and occasionally eight blades.
Finishing burs will have 12 blades.
The finer the finish more the number of blades.

63. The angle at which the face of the blade meets a line extending from the cutting edge
to the bur axis is known as the rake angle.
The more positive the rake angle.

64. The twist deillis made up of steel
It cuts only at its tip as it is pushed into the tooth in the
direction of the long axis of the instrument
It has deep twin heliocalflutes that wind around the shaft
in a tight spiral,helpingto remove chips from the hole.
Used to make small,uniformdiameter,parallel-sided holes
in dentin to receive retentive pins for restorations.
The drill diameter is slightly larger than the pins that are
incorporated into cast restorations to allow for a small
cement space.
The working portion of this type of drill should be 3 –5
mm long.
a shallow pilot hole is made with no.1/2 round bur on a
narrowhorizontalledge to ensure that the hole will be
drilled precisely in its intended position.

65. 0.6 mm twist drill,pinholes for parallel pins for cast
restorations
0.5 mm Kodexdrill used for creating pinholes for minim
threaded pins,whichretain amalgam and
compositecores.

66. Dual instrumentation
Diamond burs cut through enamel more efficiently
than carbide burs but they leave micro scratceson
the surface reducing the finish of the preparation.
Leading to rough cavosurfaceand marginal
preparation with diamond burs.
Hence for preparation of grooves ,box forms ,
isthmus etc
Here both diamond and carbide burs are used of
the same length and diameter which are
configured

67. Clearance angle
Rake angle

68. Commonerrorsoftoothpreparation:
1.Insufficientocclusalorincisalreduction.
2.Lackofuniformreductionoflabialorbuccalsurfacescompromisingesthetics.
3.Minimumaxialreductiononthebuccalandlingualsurfaceoftheposteriorteeth,
whichincreasestheincidenceofworkingprematurities.Thedistinctionbetween
reductionandclearanceiscrucial.
4.Inappropriateproximalreduction,whichpreventshavingacleanableembrasure
space.
5.Overreductionofteethand/orviolationofthebiologicwidth.
6.Insufficientgingivalreductiontoaccommodateadefinitefinishline.
7.Undercutsonthedistolingualsurfaceofthepreparationand/orlackofparallelism
oftheFPDabutments.
8.Failuretocontourproximalsurfacesofadjacentteethtoallowseatingofa
restorations.

69. ESTHETIC CONSIDERATIONS
The restorative dentist should develop skill in
determining the esthetic expectations of the patient. Patients
prefer their dental restorations to look as natural as possible.
However, care must be taken that the esthetic considerations are
not preserved at the expense of the patient’s long term oral
health or functional efficiency.
Whenever possible, accomplishment of an esthetically
acceptable result without the use of metal-ceramic crowns is
preferred, not only because tooth structure is conserved but also
because no restorative material can approach the appearance of
intact tooth enamel.

70. CONCLUSION
Theprinciplesoftoothpreparationcanbecategorizedintobiologic,
mechanicalandestheticconsiderations.Oftenthoseprinciplesconflict,andthe
clinicianmustdecidehowtherestorationshouldbedesigned.Eachtooth
preparationmustbemeasuredbyclearlydefinedcriteria,whichcanbeusedto
identifyandcorrectproblems.Itisimportanttounderstandthepertinenttheories
underlyingeachstep.Successfulpreparationscanbeobtainedbysystematically
followingthesesteps.Itisimportanttocriticallyevaluateeachstepbefore
proceedingtothenextsteptoensureanoptimalqualityfinalrestoration,which
willservethepatientforalongtime.

71. FundamentalsofFixedprosthodonticsHerbertT.
Shillingburg,Hobo,Whitself,Jacobi,andBrackett.Third
Edition
Contemporaryfixedprosthodontics.StephenF.
Rosensteil,MartinF.LandandJunheifjujimoto,Second
Edition.
Tylman’stheoryandpracticeoffixedprosthodoontics.
WilliamF.P.MaloneandDavidL.Koth.FifthEdition.
Principlesofoperativedentistry-Marzouk,3
rd
edition.
References

72. THANK YOU…!!!