1) The document discusses different types of finish lines (margins) that can be used in fixed prosthodontic treatments, including subgingival, equigingival, and supragingival margin placements.
2) It describes various margin designs such as chamfer, shoulder, knife edge, and their advantages and disadvantages. The chamfer is preferred for metal restorations due to its distinct shape and ability to distribute stresses.
3) Factors like preservation of tooth structure, retention, resistance to fracture, and health of the surrounding tissues must be considered when determining the location and design of finish lines. Subgingival margins can cause more inflammation and are best avoided unless necessary for esthetics or contour.
3. Finish line forms :-
1 chamfer
2 heavy-chamfer
3 shoulder
4 radial-shoulder
5 shoulder with bevel
6 slanted shoulder
7 knife-edge / feather-edge
8 chisel edge
Related articles
References
4. DEFINITIONS (GPT 9)
GINGIVAL FINISH LINE
1. a line of demarcation
determined by two
points
2. in dentistry, the
junction of prepared and
unprepared toot
structure with the
margin of the restorative
material
3.tooth structure with
the margin of a
restorative material
4.planned junction of
different materials
GINGIVAL FINISHLINE
THE GINGIVAL TERMINATION OF A TOOTH
PREPARATION
FINISHLINE
5. Wassell R, Nohl F, Steele J, Walls A, editors. Extra-coronal Restorations:
Concepts and Clinical Application. Springer; 2018 Jul 31.347
6. Introduction
Shillingburg HT, Hobo S, Whitsett
LD, Jacobi R, Brackett SE.
Fundamentals of fixed
prosthodontics. Quintessence
Publishing Company; 1997
Jan.299 and 325
Preservation
of tooth
structure
Retention and
resistance
Structural
durability
Marginal
integrity
Preservation
of the
periodontium
configurationof
preparationfinishline
Shape and bulk of
restorative material in the
margin of the restoration.
marginal adaptation
degree of seating of the
restoration
Marginal
adaptation
Marginal
geometry
Margin
placement
shape or
configuration of
finish line
7. Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book.
Elsevier Health Sciences; 2015 Jul 28.(page no.172)
Apical extension of
the preparation
can necessitate
additional tooth
reduction
Preparations for periodontally involved teeth may necessitate considerable
reduction if the margins are to be placed subgingivally for esthetic reasons.
A shoulder margin
(2) is less
conservative
than a chamfer (1).
8. recurrent caries
or periodontal
disease
1.dissolution of
luting agent
2.inherent
roughness
Avoided by
smooth and
even margin
Tissue displacement
impression making
Die formation
Waxing
Casting
Marginal
gap
Cast
metal
10
microns
ceramic
50Rosenstiel SF, Land MF, editors.
Contemporary Fixed Prosthodontics-E-Book.
Elsevier Health Sciences; 2015 Jul 28.(page
9. Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-
E-Book. Elsevier Health Sciences; 2015 Jul 28.(page no.175)
10. Margin placement and preservation
of periodontium
1. AT THE BASE OF THE GINGIVAL CREVICE (GLICKMANN & STEIN )
2. HALF THE DISTANCE BETWEEN THE BASE OF THE GINGIVAL CREVICE AND THE
GINGIVAL MARGIN (SD TYLMANN)
3. SLIGHTLY BELOW THE GINGIVAL MARGIN ( R HERLANDS & L A
WEINBERG )
4. AT THE CREST OF THE GINGIVAL MARGIN ( J MACRUM )
5. SUPRA-GINGIVALLY (EISSMANN, RICHTER AND UENO,
SCHLUGER,SILNESS,PRESTON)
Rangarajan V, Padmanabhan TV. Textbook of Prosthodontics-E Book. Elsevier
11. SUPRAGINGIVAL MARGINS
Does not violate the gingival complex especially in areas where there is
inadequate zone of attached gingiva
Proposed in 1941 by ORBAN for improved
periodontal health
CHRISTENSEN demonstrated that the visually
accessible Supra-gingival margin can be BETTER
FITTED than sub-gingival margins
Easier to prepare
with accuracy
without trauma
to the soft tissues
Can be situated
in the hard
enamel
Easily finished
Easy to keep
clean, oral
hygiene
Impressions made
easily with less
potential for soft
tissue damage
Ease of
evaluation of
restoration on
recall
Rangarajan V, Padmanabhan
TV. Textbook of Prosthodontics-
E Book. Elsevier Health
Sciences; 2017 Jul 11.1928
Rosenstiel SF, Land MF, editors.
Contemporary Fixed Prosthodontics-E-Book.
Elsevier Health Sciences; 2015 Jul 28.(page
12. SUB-GINGIVAL MARGIN
(INTRA-CREVICULAR : TYLMANN)
1968- LOË – PROVED SUB-GINGIVAL MARGINS MAJOR
CAUSE FOR PERIODONTAL DISEASE
The deeper the restoration margin is in the sulcus,
greater is the inflammatory response. They are best
avoided unless indicated.
Placed at least 2 mm above the alveolar crest so that the
biologic width is not encroached.
Extension for
prevention-
GV BLACK
Sterile
gingival
sulcus
Christensen demonstrated that experienced restorative dentists can miss
marginal defects as great as 120 μm when the margins are subgingival
Bjorn et al: more than half of the proximal
margins of gold crowns had defects greater than 0.2 mm and more than 40%
of the proximal margins of ceramic crowns had defects that exceeded 0.3 mm.
Shillingburg HT, Hobo S,
Whitsett LD, Jacobi R,
Brackett SE. Fundamentals
of fixed prosthodontics.
Quintessence Publishing
Company; 1997 Jan.299
and 325
13. INDICATIONS FOR
SUB-GINGIVAL MARGINS:
1. Esthetic demands
2. Sub-gingival tooth fracture,erosion,abrasion
3. Caries removal
4. Cover existing Sub-gingival restorations
5. To gain the needed crown length
6. To gain more favorable crown contour
7. Proximal contact areas extend into the gingival crest
8. Root sensitivity
9. Modification of axial contours needed
14. Disadvantages
Plaque retention - Greater pathogenicity of the
subgingival dental plaque
Mechanical irritation
Violation of biological width
Soft tissue injury
Inaccurate fit
Roughness of the tooth–restoration interface
Improper crown contour- Failure to maintain the
emergence profile
Usually periodontal tissues show more signs of inflammation around crowns
15. EQUI-GINGIVAL MARGIN
( AT THE GINGIVAL CREST )
MACRUM and NEWCOMB
concluded that least
amount of inflammation
seen when the margins
are placed at the
gingival crest
HARRISON attributed
this due to the presence
of KERATINIZED
EPITHELIUM, unlike the
epithelium in the
deeper gingival sulcus
When dentist is able to
control the preparation,
impression, adaptation,
cementing and sealing
Patient can keep it free
from plaque
Esthetic demands
Indications
Ferencz JL. Maintaining and enhancing gingival
architecture in fixed prosthodontics. The Journal of
prosthetic dentistry. 1991 May 1;65(5):650-7.
16. EQUIGINGIVAL MARGINS
Advantages:
Easy to impress and
finish equigingival
margins because you are
not going below the
tissue.
You can also expect to
see very healthy gingiva,
although maybe not as
healthy as it would be if
you were to stay above
the tissue.
Disadvantages:
Esthetics can become an issue but
if you go in even to the tissue, it is
less likely you will have an
unaesthetic result.
If your patient has discolored teeth
and you’re using an opaque
material, a highly esthetic result is
more difficult to achieve than if
you stayed subgingival.
Retain more plaque than
supragingival or subgingival margins
and therefore cause greater
gingival inflammation.
18. CLASSIFICATION OF MARGINAL DESIGNS
BASED ON THE MARGINAL WIDTH ( A.J
HUNTER JPD 1990;64 )
MARGINAL WIDTH LESS THAN 0.3mm
- Knife-edge/Feather Edge
MARGINAL WIDTH UPTO 0.3mm
- Chamfer
MARGINAL WIDTH GREATER THAN 0.3mm
- Shoulder
Hunter AJ, Hunter AR. Gingival crown margin configurations: a review and
discussion. Part I: terminology and widths. The Journal of prosthetic dentistry.
1990 Nov 1;64(5):548-52.
19. VARIOUS PROPOSED MARGIN
DESIGNS /FINISH LINE
CONFIGURATIONS :
1. CHAMFER
2. HEAVY CHAMFER
3. SHOULDER
4. RADIAL SHOULDER
5. SHOULDER WITH BEVEL
6. SLANTED/SLOPED SHOULDER
7. KNIFE EDGE / FEATHER EDGE
8. CHISEL EDGE
Rosenstiel SF, Land MF, editors.
Contemporary Fixed Prosthodontics-E-Book.
Elsevier Health Sciences; 2015 Jul 28.(page
20. Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul 28.(page no.176)
21. CHAMFER FINISH LINE
•a marginal finish either curved or formed by
a plane at an obtuse angle to the external
surface of a prepared tooth
BOUCHER
•A Finish line design for tooth preparation in
which the gingival aspect meets the
external axial surface at an obtuse angle
GPT 9
•a Concave extra coronal finish line that
provides greater angulation than a knife-
edge and less width than a shoulder
TYLMAN
(1965)
•a reduction of 1.5 mm ,rounded internal line
angles & cavo-suface angle of 135 deg
BELL et al
The preferred gingival finish line for veneer metal restoration
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of
fixed prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 323
22. INSTRUMENTATION :
Tapered diamond with a rounded tip ( TORPEDO DIAMOND )
The margin formed is an exact Image of the diamond
With high quality true running Hand-piece
It can be cut with the tip of a round-end diamond while the axial
reduction is being done with the side of that instrument
less likely to produce a butt joint.
Margin of the cast restoration that fits against it combines an
acute edge with a nearby bulk of metal.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics.
Quintessence Publishing Company; 1997 Jan.299 and 324
23. PREPARATION:
The diamond is held precisely in the intended path of the withdrawal
of the restoration
Tilting it away from tooth creates : UNDERCUT
Angling it towards the tooth will lead to : OVER-REDUCTION and loss of
retention
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 324
24. Rosenstiel SF, Land MF,
editors. Contemporary
Fixed Prosthodontics-E-
Book. Elsevier Health
Sciences; 2015 Jul
28.(page no.177)
25. The chamfer should never be prepared wider than half the tip of the diamond,
otherwise an unsupported LIP OF ENAMEL will result
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 324
26. ADVANTAGES
1. Distinct and easily identifiable margin, providing
adequate bulk for material.
2. Accurate die trimming for fabrication of cast restoration
3. Easier to control
4. Exhibits least stresses (the round concavity produces
lower stress concentration within the cement film)
5. A uniform type of geometry gingivally is established with
a chamfer preparation
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of
fixed prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 325
27. HEAVY/DEEP CHAMFER
Used to provide a 90 degree cavo-
surface angle with a large radius
rounded internal line angle.
The radius of curvature equals the
depth of axial reduction
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of
fixed prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 324
28. It is created with a round end tapered diamond, which,
in the hands of an unskilled operator, can create an
undesirable fragile lip of enamel at the cavosurface
This friable, unsupported enamel is very easily
fractured during or after cementation of the
restoration.
provides better support for a ceramic crown than does a
conventional chamfer, but it is not as good as a
shoulder.
A bevel can be added to the deep chamfer for use with
a metal restoration
Shillingburg HT, Hobo
S, Whitsett LD, Jacobi
R, Brackett SE.
Fundamentals of fixed
prosthodontics.
Quintessence
Publishing Company;
1997 Jan.299 and 325
29. SHOULDER
Def : one that makes a 90 deg. Angle with the vertical axial wall of the
preparation
Also defined by an external cavo-surface angle of 90 deg. With a butt joint of
restoration and tooth at the margin
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett
SE. Fundamentals of fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan.299 and 325
30. DISADVANTAGES
• difficult to prepare
• Stress
analysis,microleakage,
puplal response not
favorable
• Sharp 90 deg. Internal
line angle
concentrates stress >
CORONAL FRACTURE
• Excess tooth
destruction, bulky and
unsuitable marginal
finish, except when
modified with bevel
• Thickened wax pattern
increases CASTING
SHRINKAGE
ADVANTAGES
• Wide ledge provides
resistance to occlusal
forces and minimizes
stresses that may lead to
fracture of porcelain
• Increased structural
rigidity
• Clear impression and
dies
• Provides space for
healthy restoration
contours
• maximum esthetics
• Bulk of the restoration
Ibbetson RJ. Tylman's theory and practice of fixed prosthodontics: Edited by
William FP Malone and David L. Koth. Pp. 461. 1989. Ishiyaku EuroAmerica
(distributed by Gazelle Book Services, Lancaster). Hardback
31. All ceramic
restorations
Facial margins
of metal-
ceramic crowns
Indications
Ibbetson RJ. Tylman's theory and practice of fixed prosthodontics:
Edited by William FP Malone and David L. Koth. Pp. 461. 1989.
Ishiyaku EuroAmerica (distributed by Gazelle Book Services,
Lancaster). Hardback
It is prepared using a flat end tapering diamond
32. TO BEVEL…OR NOT TO BEVEL
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 322
34. SHOULDER WITH A BEVEL
similar to a shoulder finish line but an external
bevel is created on the gingival margin of finish line
A bevel of 0.3 to 0.5mm is placed to form
recommended obtuse finish line
Bevel approaches the path of insertion of
restoration & improves Marginal adaptation
DISADVANTAGE:-
Extends the preparation into the sulcus if used on
apical margin.
Shillingburg HT, Hobo S,
Whitsett LD, Jacobi R, Brackett
SE. Fundamentals of fixed
prosthodontics. Quintessence
Publishing Company; 1997
Jan.299 and 327
35. BEVELS
Defined as : the process of slanting the
finish line and curve of a tooth
preparation
1963 ROSNER: concept of reducing the
marginal opening by use of a bevel finish
line
GILBOE & THAYER: Allowed the
incorporation of a physiological contour
in both the temporary and final crown
Allows Cast metal
margin to be bent or
BURNISHED against
the prepared surface
MARGINAL
INTEGRITY: Minimizes
marginal discrepancy
of crown that fails to
seat completely
REMOVES
UNSUPPORTED
ENAMEL: protects
from chipping
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 322
• Extremely short walls
• Facial margins of maxillary partial coverage
restorations
• Gingival finish line on the proximal box of inlay and
onlay margin
• Shoulder is already present because of destruction
by caries or presence of previous restorations
• Indicated for porcelain-fused-to-metal preparations.
INDICATIONS
36. A, A shoulder provides more bulk of metal than a heavy chamfer, which may
facilitate the laboratory steps. B, A disadvantage of the shoulder bevel is that
its margin must be placed deeper in the gingival sulcus so that the wider band
of metal will be hidden (compare d with D). C, Scanning electron micrograph of
a shoulder margin prepared with a high-speed diamond. D, This margin has
been refined with a sharp chisel. E, This has been beveled with a tungsten
carbide bur. F, This bevel was placed with a sharp hand instrument.
(Microscopy by Dr. J. Sandrik, teeth prepared by Dr. G. Byrne.)
Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book. Elsevier Health Sciences; 2015 Jul 28.(page no.177)
37. RADIAL SHOULDER
It is a shoulder finish line with rounded internal
line angle.
Indicated for all ceramic crowns,facial margin of
metal ceramic crown
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 326
38. PREPARATION:
Initial instrumentation : FLAT END TAPERED DIAMOND
A small radius rounded internal angle is instrumented with an END
CUTTING PARALLEL SIDED CARBIDE FINISHING BUR
Finishing : Mod. BIN ANGLED CHISEL
Cavo-surface angle:90 deg. Shoulder width is slightly less because of the
rounded internal angle
Stress concentration is less in the tooth
structure than with a classical shoulder
Support for the ceramic wall is good
Less conservative of tooth
structure
Shillingburg HT, Hobo S,
Whitsett LD, Jacobi R, Brackett
SE. Fundamentals of fixed
prosthodontics. Quintessence
Publishing Company; 1997
Jan.299 and 326
39. SLANTED SHOULDER/SLOPING
SHOULDER
A 120-degree sloped shoulder margin
alternative to the 90-degree shoulder for
the facial margin of a metal-ceramic
crown
reduces the possibility of leaving
unsupported enamel and yet leaves
sufficient bulk to allow thinning of the
metal framework to a knife-edge for
acceptable esthetics
But less conservative of tooth structure
Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book.
Elsevier Health Sciences; 2015 Jul 28.(page no.179)
40. KNIFE EDGE FINISH LINE
The ultimate in finish lines
zero cutting results at the
gingival termination.
The dentist employs the
rotary instrument and leans
the cutting stone or bur
inward by rotating on that
gingival termination and
cutting mostly at the
occlusal end.
It is a process of tipping the
rotary instrument
occlusally.
formed when all the
convexities coronal to the
margin of a tooth are
removed
Knife edge on
the lingual of a
mandibular
three-quarter
crown.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R,
Brackett SE. Fundamentals of fixed prosthodontics.
Quintessence Publishing Company; 1997 Jan.299
and 328
41. Disadvantages
Thin margin difficult
to wax and cast
Over-contouring of
restoration
Lack of strength
Casting is subjected
to distortion when
subjected to occlusal
loading
Difficult to locate on
a die
Does not provide
sufficient bulk
The axial reduction
may fade out
Advantages
Ultimate acute margin
for the metal
Conservation of tooth
structure
Ease of preparation
Historically : facilitated
the making of
impressions with rigid
modelling compound in
copper band, as no
ledge was formed on
which the band could
catch
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of
fixed prosthodontics. Quintessence Publishing Company; 1997 Jan.299 and 329
42. Indications
Teeth with very convex
axial surface
Surface towards which
teeth have tilted
When root amputation is
done due to periodontal
conditions
In younger patients:
inaccessible areas
In pin-ledge
preparations
Outline for partial
veneer crowns
Contra indications
IN CERAMO-METAL
MARGINS:
As hyper-contours will
always from the attempt
to place two restorative
materials in the space
left by the removal of
small amount of tooth
structure
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE.
Fundamentals of fixed prosthodontics. Quintessence Publishing Company;
1997 Jan.299 and 328
43. CHISEL EDGE
A variation of the feather edge.
It is formed when there is a larger
angle between the axial surfaces
and the unprepared tooth
structure.
It is associated with excessively
tapered prpeparation.
Unfortunately , this margin is frequently associated with a tapered
preparation or one in which the axial reduction is not correctly aligned
with the long axis of the tooth
Rangarajan V, Padmanabhan TV. Textbook of Prosthodontics-E Book.
Elsevier Health Sciences; 2017 Jul 11.1929
44. Finish line Preparation in a
Furcally Involved Teeth
Ideally be placed subgingivally.
Coronal portion of the multirooted tooth is
convex superior to the furcal region
More acceptable margin for is a gingival
chamfer.
To prepare a chamfer the margins must be
placed far enough gingivally to eliminate
undercuts.
It is necessary to “flute” the preparation
by reducing the tooth axially so that the
coronal portion of the tooth is continuous
with the roots.
The final restoration must reproduce this
fluting to develop a healthy environment
for the furca.
Baima RF. Considerations for furcation treatment Part I: Diagnosis and
treatment planning. Journal of Prosthetic Dentistry. 1986 Aug 1;56(2):138-42.
45. Baima RF. Considerations for furcation treatment Part I: Diagnosis and
treatment planning. Journal of Prosthetic Dentistry. 1986 Aug 1;56(2):138-42.
46. FINISH LINES IN CAST POSTS
AND CORES
When cutting the preparation margins for the definitive crown, a ferrule should
be preserved where possible
Wassell R,
Nohl F, Steele
J, Walls A,
editors. Extra-
coronal
Restorations:
Concepts and
Clinical
Application.
Springer; 2018
Jul 31.
47. Facio-occlusal margin of maxillary partial
coverage and MOD onlay restorations
Must meet the requirement of providing an acute edge
with a nearby bulk of metal.
The enamel must also be protected by a finishing bevel
that will leave the tooth structure at the cavosurface
angle with sufficient bulk to resist fracture and
chipping.
A bevel is mandatory if its elimination will create an
unsupported edge of enamel
48. The most commonly used
form is a narrow (0.3- to 0.5-
mm) finishing bevel
perpendicular to the path of
insertion of the restoration
A contrabevel may also be
used where function is heavy
and esthetic requirements
are minimal
There are a few situations in
which no bevel is required -
on a cusp that is bulky
enough to allow the acute
edge of metal and still finish
the enamel at the
cavosurface angle.
49. Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-E-Book.
Elsevier Health Sciences; 2015 Jul 28.(page no.179
50.
51. Wassell R, Nohl F, Steele J, Walls A, editors. Extra-coronal
Restorations: Concepts and Clinical Application. Springer; 2018 Jul
31.331
52. Wassell R, Nohl F, Steele J, Walls A, editors. Extra-coronal Restorations:
Concepts and Clinical Application. Springer; 2018 Jul 31.332
53. James Marcum (1967) Equigingival crown margins caused least inflammatory response than supra or
subgingival margins
Shillinburg HT (1973) Shoulder finish line with or without a bevel have significantly less distortion than
chamfer finish lines with or without bevel
Faucher RR (1980) Shoulder & shoulder with bevel designs have less marginal distortion than chamfer
design.
PL Block (1987) Placing the margins into the gingival crevice for the purpose of esthetics or
protection from decay can not be a good practice
Felton DA (1991) The only indications for subgingival margins are caries, existing restorative
materials, tooth abrasion or fracture, increased resistance & retention form for
short clinical crowns
Bader JD (1991) Intact surfaces with cast restorations are not significantly different from the same
surfaces without cast restorations
54. Effect of finish line variants on marginal accuracy and fracture
strength of ceramic optimized polymer/fiber-reinforced composite
crowns. Cho et al, J Prosthet Dent 2004;91:554-60.
This invitro study evaluated the marginal adaptation and fracture strength of
ceromer/FRC crowns with respect to the various types of finish lines.
Related articles
55.
56. Tooth preparations for complete crowns: An art form based on
scientific principles. Goodacre et al. J Prosthet Dent 2001;85:363
76.
Chamfer finish lines are used with all metal crowns
because they are easy to form with a tapered, round-end
diamond instrument and because they are distinct, being
readily visible on the prepared tooth, impression, and
die.
Chamfers also possess adequate bulk for restorative
rigidity, and their depth is sufficient to permit the
development of normal axial contours. Therefore,
chamfer finish lines are well suited for all-metal crowns.
Finish lines historically used with metal ceramic crowns:
chamfer, beveled chamfer, shoulder and beveled
shoulder.
For all ceramic restorations - shoulder finish lines are
recommended for all-ceramic crowns.
57. • recommended chamfer finish
line reduction depths of 0.3 to
0.5 mm
All metal
restorations
• recommended thicknesses
between 1.0 and 1.5 mm for
the porcelain-veneer marginal
area of a metal-ceramic
crown
• Shoulder-s. The mean finish
line depth recorded was 0.9
mm with a range of 0.5 to 1.8
mm
Metal
ceramic
restorations
• finish line depths for all-
ceramic crowns have ranged
from 0.5 to 1.0 mm
All ceramic
restorations
58. The Effect of Porcelain Firing and Type of Finish Line on the
Marginal Fit of Zirconia Copings. Vojdani M et al. J Dent
Shiraz Univ Med Sci., June 2015; 16(2): 113-120.
There were significant differences
between marginal fit of chamfer and
shoulder finish line groups before and
after porcelain firing.
The marginal gap of copings with
shoulder finish line was significantly
smaller than those with chamfer
configuration, but there were no
significant differences between the
two marginal designs, after porcelain
firing.
59. Finish-line designs for ceramic crowns: A systematic review and
meta-analysis. Chen et al. J Prosthet Dent 2019;91:554-60
Different finish-line designs have been advocated for tooth preparations of
ceramic crowns.
The purpose of this systematic review and meta-analysis was to evaluate the
effects of finish-line designs on the marginal and internal adaptations of
ceramic crowns.
The marginal and internal adaptations of ceramic crowns with rounded
shoulder and chamfer finish lines were included in the meta-analysis.
Ceramic crowns with rounded shoulders exhibited significantly better
marginal adaptation than those with chamfers.
Moreover, ceramic crowns with chamfers exhibited significantly better
internal adaptation than those with rounded shoulders
60. Influence of cervical finish line type on the
marginal adaptation of zirconia ceramic crowns.
comlekoglu et al, J Prosthet Dent 2018;91:554-57
The current study evaluated the effect of different cervical finish line
designs on the marginal adaptation of a zirconia ceramic.
Four different marginal finish lines (c: chamfer, mc: mini-chamfer, fe:
feather-edge and s: rounded shoulder) were prepared on phantom incisors.
61. heavy chamfer finish line exhibited more marginal
opening than rounded shoulder on In-Ceram Alumina
crowns.
90° shoulder with a rounded axiogingival line angle
design is recommended for the preparation of all-
ceramic and metal-ceramic crowns, rather than a
chamfer preparation,
rheological properties of zirconia framework material
differ from these materials in many aspects, such as
creep behavior.
This might be the cause of the poor fitting crowns with
chamfer finish line design in the current study.
shoulder type of preparation is more resistant to
distortion.
62. CONCLUSION :
When preparing teeth for Esthetic crown restorations,
the clinician must determine which cervical line is
appropriate for each specific clinical situation.
All cervical margins must be placed in the correct
position relative to the free-gingival margin, epithelial
attachment and the alveolar housing, for a successful
restoration
The placement of finish lines has a direct bearing on the
ease of fabrication of a restoration and on the ultimate
success of a restoration.
Best results can be expected from margins that are as
smooth as possible and are fully exposed to a cleansing
action.
Proper diagnosis and treatment planning, skill in
execution of tooth preparation with correct finish line
contour help to attain basic principles of tooth
preparation like marginal integration and preservation
of periodontium.
63. References
Rosenstiel , Land,Fujimoto, “Contemporary fixed prosthodontics”, III edition.
Shillingburg, “Fundamentals of fixed prosthodontics”,
Shillingburg,”Fundamentals of tooth preparation for cast metal and porcelain
restoration”.
Malone, “ Tylman’s theory and practice of fixed Prosthodontics”, VIII Edition.
Mclean JW, “ The estimation of cement film thickness by an invivo technique”,
Br Dent J,1971, 131:107-111
Geeves William, “restorative margin placement and periodontal health”, J
Prosthet Dent 1991;66:733-736
Donovan E Terry, Chee Winston, “cervical margin design with contemporary
esthetic restorations”, Dent Clin N Am 48(2004) 417-431
Rosenstiel Edwin, “to bevel or not to bevel”, Br Dent J, 1975, 389-392
Rangarajan – textbook of prosthodontics
Deepak nallaswamy – textbook of prosthodontics
64. Periodontal considerations determining the design and location of
margins in restorative dentistry. Shenoy et al. Journal of
Interdisciplinary Dentistry / Jan-Apr 2012 / Vol-2 / Issue-1
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strength of ceramic optimized polymer/fiber-reinforced composite
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Tooth preparations for complete crowns: An art form based on
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