Principles Of Tooth Preparation For Extracoronal Restoration

Principles Of Tooth Preparation
For Extracoronal Restoration
Presentation by:
Dr. Vanshree Sorathia
MDS Prosthodontist
Total no. of slides:
136 1

Objectives of discussion…
o Tooth preparation
o Need for tooth preparation
o Objectives of tooth preparation
o Biological width
o Principles
 Biological
 Mechanical
 Esthetic
o Principle for auxiliary retentive features
o Biologically oriented preparation technique (BOPT)
o References
o Conclusion
2

Tooth preparation
The mechanical treatment of dental disease or injury to
hard tissues that restores a tooth to original form.
-Tylman
The process of removal of diseased and/or healthy
enamel and dentin and cementum to shape a tooth to
receive a restoration.
-Glossary of Prosthodontic Terms 9
1. Tylman’s. Theory and practice of fixed prosthodontics. 8th edition, All India
publishers and distributors 2002.
2. The Glossary of Prosthodontic Terms, 9th edition. J. Prosthet Dent. May 2017;
117(5S):e1-e105.
3

Need for tooth preparation
o Teeth do no possess the regenerative ability found in
most other tissues.
o Hence, once enamel or dentin is lost as a result of
caries, trauma or wear, restorative materials must be
used to reestablish form and function.
o … teeth requires preparation to receive restoration.
Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed prosthodontics.
5th ed. St. Louis: Elsevier; 2016. 4

Objectives of tooth preparation
Reduction of tooth in miniature to provide retainer support
Preservation of healthy tooth structure to secure resistance
form
Provision for acceptable finish lines
Performing pragmatic axial reduction to encourage favourable
tissue responses from artificial crown contours; fluting of molars
Tylman’s. Theory and practice of fixed prosthodontics. 8th edition, All India
publishers and distributors 2002. 5

According to Shillinburg
Preservation of tooth structure
Resistance and retention form
Structural durability
Marginal integrity
Preservation of periodontium
Herbert T. Shillinburg. Fundamentals of fixed prosthodontics. 4th edition,
Quintessence Publishing Co 2012.
6

7

According to Rosensteil
Biological
Esthetic
Mechanical
5th ed. St. Louis: Elsevier; 2016.
8

A. Biological considerations
1. Conservation of tooth structure
2. Avoidance of overcontouring
3. Supragingival margins
4. Harmonious occlusion
5. Protection against tooth fracture
9

Biologic width
Dr. Walter Cohen – 1962
Definition-
Physiological dimension
of junctional epithelium
and connective tissue
attachment above the
level of alveolar crest.
Carranza’s. Clinical periodontology. 10th edition, Elsevier 2010. 10

Biologic width:
Carranza’s. Clinical periodontology. 10th edition, Elsevier 2010 11
Anterior teeth 1.75mm
Premolars 1.97mm
Molars 2.08mm

Significance of biologic width
o Ectodermal tissues
o Teeth and implants - As barrier and prevents
the penetration of microorganisms into
periodontium.
o Remove any irritation that may damage
periodontium.
12
Sharma A, Rahul GR, Gupta B, Hafeez M. Biological width: No violation
zone. Eur J Gen Dent 2012;1:137-41.

o Bone loss of unpredictable
nature
o Gingival tissue recession
Body attempt to recreate a
room between alveolar bone
and margin to allow space for
tissue reattachment.
o Gingival hyperplasia with
thick gingival biotype with
minimal or no bone loss.
13
Response to violation of biological width:

Sharma A, Rahul GR, Gupta B, Hafeez M. Biological width: No violation zone.
Eur J Gen Dent 2012;1:137-41.
14
Bermuda Triangleof Dentistry/Devil’s triangle

o Evaluation of biologic width:
Bone sounding/transgingival probing
15
 Probing depth –
sulcus depth
 If <2mm at any
location –
violation of
biologic width.

o Kois, 2000-
Normal crest patient (85%)
High crest patient (2%)
Low crest patient (13%)
Sharma A, Rahul GR, Gupta B, Hafeez M. Biological width: No violation zone.
Eur J Gen Dent 2012;1:137-41. 16

a. Prevention of damage during tooth
preparation
Soft tissue
Adjacent
tooth
Pulp

b. Conservation of tooth structure
18
RDT ∞
1
Pulpal response
Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed prosthodontics. 5th
ed. St. Louis: Elsevier; 2016.

19
Partial coverage crowns Minimal taper Anatomic plane
Axial wall Marginal geometry Apical extension

c. Considerations affecting future
dental health
Improper preparations – adverse effect on long term
dental health.
o Insufficient axial reduction – over contoured
restoration – hampers plaque control – periodontal
disease and dental caries.
o Inadequate occlusal reduction – poor form, occlusal
dysfunction.
o Poor choice of Margin location.
20

Considerations affecting future dental health…
1. Axial reduction
2. Margin placement
3. Margin adaptation
4. Margin geometry
21

1. Axial reduction
22

2. Margin placement
23

Supra gingival
margins
Equi gingival Sub gingival
margins
1. Easier to prepare At crest of marginal
gingiva
Dental caries, cervical
erosion, restoration sub-
gingivally, crown
lengthening not indicated
2. Situated on hard enamel More impact on
periodontium
Situated on dentin &
cementum
3. Plaque free More plaque retentive Proximal contacts
extended to gingival crest
4. Impressions Gingival discoloration
common
Additional retention &
resistance
5. Evaluation easier Anterior PFM crowns
6. Root sensitivity
24

publishers and distributors 2002.
25

Margin placement guidelines…
oIf probing depth 0.5mm or less – margin 0.5mm below
the crest.
oIf >1.5mm – margin half the depth of sulcus below the
crest.
oIt >2.0mm – gingivectomy.

3. Margin adaptation
27

Bermuda Triangle of Dentistry

4. Margin geometry or configuration
Guidelines for margin designs..
– Ease of preparation without overextension or
unsupported enamel at cavosurface line angle.
– Ease of identification in impression or optical scan and
on the virtual/die.
– A distinct boundary to which the wax pattern can be
finished or the design terminated.
– Sufficient bulk of material.
– Conservation of tooth structure.
29

FINISH LINES
A line of demarcation determined by two points; the
planned junction of different materials.
-Glossary of Prosthodontic Terms 9
Fundamental criteria for successful margins:
1. Acceptable marginal adaptation
2. Tissue tolerant surfaces
3. Adequate contour
4. Sufficient strength
30
The Glossary of Prosthodontic Terms, 9th edition. J. Prosthet Dent. May
2017; 117(5S):e1-e105.

31
Herbert T. Shillinburg. Fundamentals of fixed prosthodontics. 4th
edition, Quintessence Publishing Co 2012.

Based on configuration
32
Feather
edge
Knife edge Chamfer Bevel Shoulder Beveled
shoulder

According to width
33
AJ Hunter, AR Hunter. Gingival crown margin configurations: A review and
discussion. Part I: Terminology and widths. J Prosth Dent 1990;64:548-52.
<0.3mm Knife edge or feather edge
0.3mm Chamfer
>0.3mm Shoulder

1. Chamfer
Salient features:
A finish line design for tooth
preparation in which the
gingival aspect meets the
external axial surface at an
obtuse angle.
-Glossary of
Prosthodontic Terms 9
34
The Glossary of Prosthodontic Terms, 9th edition. J. Prosthet Dent. May
2017; 117(5S):e1-e105.

o According to El Ebrashi et al, acceptable stress
distribution and an adequate seal.
o Enhances accurate die trimming for technical
fabrication of cast restorations.

36
Instrumentation -

2. Heavy chamfer or deep chamfer
Salient features:
 To provide a 90⁰ cavosurface angle with a large
radius rounded internal angle. The radius of
curvature equals the depth of reduction.
 A bevel can be added for use with a metal
restoration.
37

38
Instrumentation -

3. Classic shoulder
Salient features:
 Wide ledge provides resistance to occlusal forces and
minimizes the stress that might lead to # of porcelain.
 Usage increased after introduction of ‘injectable
ceramic’ crowns such as Dicor and Cerestore.
39
Tylman’s. Theory and practice of fixed prosthodontics. 8th edition, All
India publishers and distributors 2002.

40
Instrumentation -
Advantages Disadvantages Indications
• Bulk of material
• Permits more latitude
for gingival contour of
cast restorations
• Less conservative of
tooth structure
• Stress concentration at
90⁰ internal line angle,
hence conductive of
coronal fracture.
• Facial margin of metal
ceramic crown
• Complete ceramic
crown

4. 120⁰ sloped shoulder
Salient features:
o Reduces the possibility of leaving unsupported
enamel but leaves sufficient bulk to allow thinning of
the metal framework to a knife edge for acceptable
esthetics.

5. Radial shoulder
Salient features:
 Modified form of shoulder finish line.
 The radius of curvature equals 1/4th to 1/5th the
depth of axial reduction.
42

43
Instrumentation -

 Finite element analysis of preparation finish lines.
 Deep chamfer will produce slightly less stress than a
radial shoulder , it only amounts to a 7% decrease.
44
Finish line Stress (psi) Reduction (%) Change (%)
Radial
shoulder
2101 27 27
Deep chamfer 1897 34 7

6. Shoulder with bevel
Salient features:
 The angle of bevel approaches
the path of insertion of
restoration and improves
marginal adaptation.
45

Indications:
1. Proximal box of inlays and onlays.
2. Occlusal shoulder of onlays and mandibular 3/4th
crown.
3. Facial finish line of PFM where esthetic is not
critical.
4. Shoulder is already present because of caries or
restoration.
5. Extremely short walls as it facilitates axial walls that
are nearly parallel.
46

7. Knife edge or chisel edge
Salient features:
 Permits an acute margin of metal.
47
Minimal
destruction
Over contouring
restoration
Poor esthetics
Weaker crown
margin
Lingual surface of
mandibular
posterior teeth
Teeth with very
convex axial
surfaces
Surface towards
the tilt of tooth

Instrumentation -
48

8. Feather edge
49
Conservation of
tooth structure
Does not
provide
sufficient bulk
Not
recommended

d. Occlusal considerations
o Supra-erupted or tilted teeth.
o Considerable reduction to compensate supra
eruption of abutment.
o May shorten tooth preparation axial wall height with
associated mechanical consequences such as
reduced retention and resistance.

e. Preventing tooth fracture

B. Mechanical considerations
1. Retention form
2. Resistance form
3. Preventing deformation
52

Factors affectingretention…
1. Magnitude of the dislodging forces
2. Geometry of tooth preparation
1) Taper
2) Surface area
3) Stress concentration
4) Type of preparation
3. Roughness of the finishing surface of
restoration
4. Materials being cemented
5. Film thickness and properties of the luting
agent
54

1. Magnitude of dislodging forces
….Exerted by elevator muscle depends upon,
- Stickiness of food
- Surface area & surface texture of restoration

o Cement
o Cylindrical preparation

(i) Taper
o Angle of convergence.
o Undercut.
o Optimum 2.5⁰ to 6.5 ⁰.
 Too small a taper – unwanted
undercut
 Too large a taper – lack of
retention

Significance:
1. Easy path of insertion
2. Visualization of finish line
3. To compensate casting shrinkage
59

Jorgensen & Kaufman et al – retention decreases as
taper increases

o Ward, 5% to 20% per inch (3 to 12 degree).
o Only a slight increase in stress as taper is increased
from 0 to 15 ⁰. However at 20 ⁰, stress concentration
increases sharply.
o Ohm and Silness,
Vital teeth - MD - 19.2 ⁰ FL - 23 ⁰
Non vital teeth – MD – 12.8 ⁰ FL – 22.5 ⁰
Quintessence Publishing Co 2012. 61

 Optimum degree of tooth preparation taper
Tooth M/D F/L Overall
Maxillary
Anterior teeth
Premolar
Molar
10
14
17
10
14
21
10
14
19
Mandibular
Anterior teeth
Premolar
Molar
10
16
24
10
12
20
10
14
22

Path of insertion
o Is an imaginary line along which the restoration will
be placed onto or removed from the preparation.
o Visual survey ensures – preparation is neither
undercut or over tapered.

o Center of occlusal surface of preparation is viewed
with one eye from a distance of 30 cm (12”).
o Binocular vision avoided – undercut preparation can
appear to have an acceptable taper.
edition, Quintessence Publishing Co 2012. 64

Considered in two dimensions:
1. Faciolingually: affects the esthetics of metal ceramic
or partial veneer crowns.
Posterior 3/4th crown – parallel to long axis of tooth.
Anterior 3/4th crown – parallel to incisal 1/2 of the
labial surface.

2. Mesiodistally: parallel to contact areas of
adjacent teeth.
Tilted tooth – locked out.

(ii) Surface area
• Length of path of placement – surface area that is in
sliding contact.
• Tall v/s short axial wall, molar v/s premolar.
• Surfaces where crown is pulled away – less retention.
• Can be increased by adding groove.

(iii) Stress concentration
o Cohesive failure of cement.
o Sharp occlusoaxial line angles – rounded.

(iv) Type of preparation

Auxiliary retentive features
o Basic unit of retention – opposing axial walls with minimal
taper.
o Opposing walls not available for use:
Severely mutilated tooth structure.
Partial veneer crowns
Greater than desirable inclination.
70

Principles of substitution
1. The central “core” (pulp and 1
mm thick surrounding layer of
dentin) must not be invaded in
vital teeth.
No retentive features should extend
further into the tooth than 1.5mm at
cervical line or from central fossa.
If caries removal – deeper cavity – any
part lying within vital core should be
filled with GIC.
71

2. No walls of the dentin should be reduced to
thickness less than its height for the sake of
retention.
May preclude the use of full veneer crown.
Or if used, might require core or foundation
restoration.
72

a. Box forms
o Substituted the grooves.
o Indication - Small to moderate interproximal caries or prior
restoration.
o Dual purpose – caries removal + retention.
o Large amount of tooth reduction - Not used on an intact surface.
73

b. Grooves
o Indication: Short axial walls.
o Salient feature: Placed on a vertical walls of bulk tooth structure,
at least 1mm wide and deep and as long as possible.
o Multiple grooves as effective as box.
o Oversized box – when facial and lingual walls are too apart.
o Too many – adversely affect seating of full veneer crown.
74

c. Pins
o Increase length internally and apically.
o Used in two ways:
75
Parallel pins Non Parallel pins

Guidelines for drilling pin holes:
1. Placed in sound dentin.
2. Enamel should not be undermined.
3. Perforation into periodontal membrane should be
avoided.
4. Pulp should not be encroached upon.
76

Salient features:
Pinholes – placed vertically in shoulders or ledges
halfway between the outer surface of tooth and the
pulp surrounded by at least 0.5mm of dentin.
o Safest location – line angles of corner of teeth.
o Least desirable area – midway between corners,
especially in region overlying the furcation.
o Pulp – Endo; Perforation to sulcus – exposed with
surgical flap and smoothen.
77

3. Roughness of the surface being
cemented
o When internal surface of restoration – very smooth –
retentive failure – between cement restoration
interface.
o Retention increased - if restoration is roughened or
grooved. Air abrasion – 50um of alumina OR Acid
etching.
o Rare failure at cement to tooth interface.

4. Materials being cemented
o Affected by
Type of casting alloy
Any core or buildup material on axial wall of crown
preparation
o More reactive the alloy -
more adhesion
o Base metal alloy –
better retained

5. Luting agent
a. Type of luting agent
Adhesive resin cement are most retentive.
b. Film thickness of luting agent
Effect uncertain.

Factors influencingthe retentionof a cemented
restorations
Factor Greater retention Lesser retention
Taper Parallel 6⁰ Excessive
Surface area Large Small
Type of preparation M CC PM CC Partial crown Intracoronal restorations
Surface texture Rough Smooth
Film thickness Efficient uncertain
Luting agent Adhesive resin GIC Zn polycarb/ ZoE ZnP

Summary
A. A. Definition and Objectives
B. B. Principles
a) Biological considerations:
1. Prevention of damage during tooth preparation
2. Conservation of tooth structure (RDT, 6 guidelines)
3. Considerations affecting future dental health
4. Occlusal consideration
5. Prevention of tooth fracture
82
Adjacent tooth
Soft tissue
Pulp
Temperature
Chemical agents
Bacterial action
Axial reduction
Margin placement – supra v/s sub gingival
Marginal adaptation – smooth v/s rough
Marginal geometry – 8 finish lines

b) Mechanical considerations:
1. Retention form
i. Magnitude of dislodging forces
ii. Geometry of tooth preparation
iii. Roughness of fit surface of restoration
iv. Materials being cemented
v. Luting agent
83
Summary
Taper – Path of insertion
Surface area
Stress concentration
Type of preparation
Auxiliary retentive features

Principles Of Tooth Preparation
For Extracoronal Restoration
-Part 2
Seminar no. 8
Presentation by:
Dr. Vanshree Katarya
2nd year Post Graduate
Scholar
Date: 21/01/2020
22/01/2020
Guided by:
Dr. Meenakshi T.
Professor and Head
Total no. of slides:
137
86

Objectives of discussion…
o Principles
Mechanical –
 Resistance form
 Preventing deformation
Esthetic
o Biologically oriented preparation technique (BOPT)
o References
o Conclusion
87

Factors affectingresistance…
1. Magnitude and direction of the
dislodging forces
3. Physical properties of luting agent
89

1. Magnitude and direction of dislodging
forces
o Normal occlusion - biting force distributed all over tooth;
most of it is axially directed.
o Fixed prosthesis – load should be well distributed and
favorably directed.
o Bruxism and pipe smokers
o Withstand oblique and axial forces.
o Occlusal forces – 50-65lb.

Resistance is a function of relationship between
1. Axial wall taper (1/α)
2. Preparation diameter (1/α)
3. Preparation height (α)

(i) Taper
• 5-22⁰ - clinically acceptable range.

(ii) Preparation diameter
Arc of displacement

(iii) Preparation height
Freedom of displacement
• 3-mm preparation height provides adequate
resistance, if taper is restricted to 10⁰ or less.
• Molar crown – minimal preparation height 3.5-4mm.

o Partial coverage v/s complete coverage restorations.
o Grooves and/or boxes.
o Grooves of greater depth at cervically than occlusally
for excessively tapered preparations.

96
Grooves - Oblique v/s perpendicular walls
Box - Oblique v/s perpendicular walls

3. Physical properties of luting agent
Compressive strength and modulus of elasticity.

Compressive strength:
To satisfy ADA sp. No. 96, the compressive strength
of ZnP cement must exceed 70MPa at 24 hours. GIC
and most resins have higher compressive strength.
Increasing temperature – effect on compressive
strength. Eg: ZnOE – room temperature (23⁰C) to
body temperature (37⁰C) halves the compressive
strength of reinforced ZnOE cement; rise in temp to
50⁰C (hot food) reduces it over 80%.

Modulus of elasticity:
ZnP cement > Zn Polycab ( exhibits relatively large
plastic deformation).
Therefore, Retentive ability of Zn Polycarb cement is
more dependent on taper of preparation than is the
retention with ZnP.

Factors influencingthe resistance of a cemented
restorations
Factor Greater resistance Lesser resistance
Dislodging forces Habits Eccentric interferences Anterior guidance
Taper Minimum 6⁰ Excessive
Diameter Small (Premolar) Large (Molar)
Height Long Average Short
Type of preparation Complete coverage Partial coverage Onlay
Luting agent Adhesive resin GIC ZnP Zn polycarb/ ZoE

C. Preventing deformation..
101

1. Alloy selection
Type III & IV gold alloys.
They are harder and their strength and hardness can
further be increased by heat treatment.

2. Adequate tooth reduction
(Structural durability)
Even the stronger alloys need sufficient bulk, if they are
to withstand occlusal forces.
 Occlusalreduction
 Functionalcusp bevel
 Axialreduction

3. Margin design
o Avoid occlusal contact – keeping preparation margins
approx. 1 to 1.5 mm away from occlusal contact.
o Feather edge v/s Chamfer – bulk of restoration.
o Grooves or ledges – partial coverage crown.
o Pin ledge restoration.

C. Esthetic considerations
1. Minimal display of metal
2. Maximum thickness of porcelain
3. Porcelain occlusal surfaces
4. Subgingival margins
105

A. All ceramic restorations..
106

107

B. Metal ceramic restorations..
108

109

C. Partial coveragerestorations..
110

111

b) Mechanical considerations:
2. Resistance form
i. Magnitude and direction of dislodging forces
ii. Geometry of tooth preparation
iii. Physical properties of luting agent
3. Preventing deformation
c) Esthetic considerations:
112
Summary
Freedom of displacement
Proximal grooves and boxes
Partial veneer crown v/s Complete crown
Alloy selection
Adequate tooth reduction – structural durability
Margin design
Partial veneer crown
Porcelian fused to metal crown
All ceramic crown

Planning and evaluating tooth
preparations
Diagnostic tooth preparation, Indexing
i. Selecting the appropriate path of placement.
ii. Deciding on amount of tooth reduction.
iii. Determining the best location of facial and
proximal margins of partial veneer crowns.
iv. Prefabrication of interim restorations.

Diagnostic waxing procedure
i. Determine optimal contour and occlusion of
eventual prosthesis.
ii. Benefit – anterior guidance or occlusal scheme
has to be altered.
114

Evaluative procedures during tooth
preparation.
Index
Check cast
115

Biologically Oriented Preparation
Technique (BOPT)
IgnazioLoi 2013
Unsatisfactory esthetic results due to apical
migration of gingiva:
a. Thin gingival biotype
b. Reaction to trauma due to prosthetic work
c. Chronic inflammation due to prosthesis
d. Trauma due to inadequate tooth brushing
Ignazio Loi, Antonello Di Felice. Biologically Oriented Preparation Technique
(BOPT): A new approach for prosthetic restoration of periodontically healthy
teeth. Eur J Esthet Dent 2013;8:10-23. 116

o Preparation with finish line – Horizontal
preparation.
Clinical crown = anatomical crown
o Preparation without finish line – feather edge
margin
Clinical crown ǂ anatomical crown
teeth. Eur J Esthet Dent 2013;8:10-23.
117

Clinical advantages of BOPT:
1. Erasure of anatomic CEJ in unprepared teeth
and deletion of previously existing finish lines
on already prepared tooth.
2. Possibility to place final finish line at different
levels without affecting quality of marginal
adaptation of restoration.
teeth. Eur J Esthet Dent 2013;8:10-23. 118

3. New prosthetic CEJ.
4. Conservation of tooth structure.
5. Ease and fast to execute.
6. Ease in relining and finishing temporary
crown.
7. Ease in impression making.
(BOPT): A new approach for prosthetic restoration of periodontically healthy teeth.
Eur J Esthet Dent 2013;8:10-23.
119

Biologic advantages of BOPT:
1. Increase in gingival thickness.
2. Increased stability of gingival margin over a
time.
3. Possibility to coronalize gingival margins by
remodeling emergency profile.
120

Technique
1. Preparation:
Ignazio Loi, Antonello Di Felice. Biologically Oriented Preparation Technique (BOPT):
A new approach for prosthetic restoration of periodontically healthy teeth. Eur J
Esthet Dent 2013;8:10-23.
121

122

123
2. Temporary crown relining:

124

125

126

3. Impressiontechnique:
o After a minimum of 4 weeks, gingival tissues
will be stabilized.
o Use of two retraction cord is strongly
suggested.
127

4. Laboratory procedures:
128
Ignazio Loi, Antonello Di Felice. Biologically Oriented Preparation Technique (BOPT): A new approach for prosthetic
restoration of periodontically healthy teeth. Eur J Esthet Dent 2013;8:10-23.

129

Final prosthesis:
130

Ezatollah Jalalian, Neda Sadat Aletaha. The effect of two marginal designs (chamfer
and shoulder) on the fracture resistance of all ceramic restorations, Inceram: An in
vitro study. Journal of Prosthodontic Research. 2011;55:121-125.
132

Serra-Pastor, B., Loi, I., Fons-Font, A., Solá-Ruíz, M. F., & Agustín-Panadero, R. Periodontal
and prosthetic outcomes on teeth prepared with biologically oriented preparation
technique: a 4-year follow-up prospective clinical study. Journal of Prosthodontic
Research. 2019;63:415-420.
133
1. Good
periodontal
behavior
2. Increase
of gingival
thickening,
3. Marginal
stability

Glanluca Paniz, Jose Nart, Luca Gobbato, Andrea Chietico, Diego Lops, Konstantinos
Michalakis. Periodontal response to two different subgingival restorative margin
designs: 12-month randomized clinical trial. Clin Oral Invest. 2015.
134

References
1. Tylman’s. Theory and practice of fixed prosthodontics. 8th
edition, All India publishers and distributors 2002.
2. The Glossary of Prosthodontic Terms, 9th edition. J. Prosthet
Dent. May 2017; 117(5S):e1-e105.
3. Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed
prosthodontics. 5th ed. St. Louis: Elsevier 2016.
4. Herbert T. Shillinburg. Fundamentals of fixed prosthodontics.
4th edition, Quintessence Publishing Co 2012.
136

5. Carranza’s. Clinical periodontology. 10th edition, Elsevier
2010.
6. Sharma A, Rahul GR, Gupta B, Hafeez M. Biological width: No
violation zone. Eur J Gen Dent 2012;1:137-41.
7. AJ Hunter, AR Hunter. Gingival crown margin configurations:
A review and discussion. Part I: Terminology and widths. J
Prosth Dent 1990;64:548-52.
8. Ignazio Loi, Antonello Di Felice. Biologically Oriented
Preparation Technique (BOPT): A new approach for
prosthetic restoration of periodontically healthy teeth. Eur J
Esthet Dent 2013;8:10-23.
137

9. Rubén Agustín-Panadero, María Fernanda Solá-Ruíz, César
Chust and Alberto Ferreiroa. Fixed dental prostheses with
vertical tooth preparations without finish lines: A report of
two patients. J Prosthet Dent 2015.
10. Ezatollah Jalalian, Neda Sadat Aletaha. The effect of two
marginal designs (chamfer and shoulder) on the fracture
resistance of all ceramic restorations, Inceram: An in vitro
study. Journal of Prosthodontic Research. 2011;55:121-125.
11. Serra-Pastor, B., Loi, I., Fons-Font, A., Solá-Ruíz, M. F., &
Agustín-Panadero, R. Periodontal and prosthetic outcomes
on teeth prepared with biologically oriented preparation
technique: a 4-year follow-up prospective clinical study.
Journal of Prosthodontic Research. 2019;63:415-420.
138

139
12.Glanluca Paniz, Jose Nart, Luca Gobbato, Andrea Chietico,
Diego Lops, Konstantinos Michalakis. Periodontal response to
two different subgingival restorative margin designs: 12-
month randomized clinical trial. Clin Oral Invest. 2015.

Principles Of Tooth Preparation For Extracoronal Restoration

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