Gingival finish lines in fixed prosthodontics

GINGIVAL FINISH LINES IN FIXED PARTIAL DENTURES

1. FINISH LINES IN FPD
NamithaAP
II MDS
DEPT.OF PROSTHODONTICS

2. CONTENTS
Introduction
Marginal integrity
Requirements for successful restoration of margins
Burs
To bevel, or not to bevel
Margin placement
Margin adaptation
Marginal geometry/finish lines

3. Definition
Finish line location :-
1 sub-gingival
2 equi-gingival
3 supra-gingival
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

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.the planned junction
of different materials
GINGIVAL FINISHLINE
THE GINGIVAL TERMINATION OF A TOOTH
PREPARATION
FINISHLINE

5. 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
configuration of
preparation finish line
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

6. 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 periodontallyinvolved teeth may necessitate considerable
reduction if the margins are to be placed subgingivallyfor estheticreasons.
A shoulder margin
(2) is less
conservative
than a chamfer (1).

7. Rosenstiel SF, Land MF, editors. Contemporary Fixed Prosthodontics-
E-Book. Elsevier Health Sciences; 2015 Jul 28.(page no.175)

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
50
microns
Rosenstiel SF, Land MF, editors.
Contemporary Fixed Prosthodontics-E-Book.
Elsevier Health Sciences; 2015 Jul 28.(page
no.174)

9. 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, PadmanabhanTV. Textbook of Prosthodontics-E Book. Elsevier
Health Sciences; 2017 Jul 11.1929

10. 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
no.174)

11. SUB-GINGIVAL MARGIN
(INTRA-CREVICULAR : TYLMANN)
1968-LOË –PROVED SUB-GINGIVAL MARGINS MAJOR
CAUSE FOR PERIODONTAL DISEASE
Subgingival margins have been described as a major
aetiologic factor in periodontitis.
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 μmwhen 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,
WhitsettLD, Jacobi R,
Brackett SE. Fundamentals
of fixed prosthodontics.
Quintessence Publishing
Company; 1997 Jan.299
and 325

12. 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.When the margin of the metal ceramic crown is to be hidden behind the
labio-gingival crest
9.Root sensitivity cannot be controlled by more conservative procedures
10.Modification of axial contours needed
11.Insufficient vertical length for retention
12.Additional retention and / or resistance is needed

13. Examples where subgingival margins are indicated. A, To include an existing
restoration. B, To extend apical to the proximal contact (adequate proximal
clearance). C and D, To hide the metal collar of metal-ceramic crowns.
Rosenstiel SF, Land MF, editors.
Contemporary Fixed Prosthodontics-E-Book.
Elsevier Health Sciences; 2015 Jul 28.(page
no.174)

14. Disadvantages
Plaque retention
Margin placement(DEFECTIVE MARGINS)
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
Greater pathogenicity of the subgingivaldental plaque.
Usually periodontal tissues show more signs of inflammation around crowns

15. 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 canbecome 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.

16. 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.

17. Ease of
preparation
Ease of
identification
Distinct
boundary
Sufficient
strength
Conservation
of tooth
structures
Guidelines
for margin
design:-
Rangarajan V, Padmanabhan TV. Textbook of Prosthodontics-E Book. Elsevier Health Sciences; 2017 Jul 11.1929
The shape of the diamond point/bur
determines the finish line
configuration and the taper.
PLAQUE
CONRTOL
ESTHETICS
MARGINAL
INTEGRITY

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
A. Feather edge
B. Chisel
C. Chamfer
D. Bevel
E. Shoulder
F. Sloped shoulder
G. Beveled shoulder
Rosenstiel SF, Land MF, editors.
Contemporary Fixed Prosthodontics-E-Book.
Elsevier Health Sciences; 2015 Jul 28.(page
no.176)

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-sufaceangle 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
Margin depends on 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
Possesses greater
angulations than a
knife edge with less
width than a
shoulder.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE.
Fundamentals of fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan.299 and 324

26. ADVANTAGES INDICATIONS
1.Distinct and easily identifiable margin,
providing adequate bulk for material.
2.Acceptable stress distribution & adequate seal
(less chances of cement failure)
3.Accurate die trimming for fabrication of cast
restoration
4.The cast restoration fits with acute edge with
nearby bulk of metal
5.Easier to control
6.Exhibits least stresses (the round concavity
produces lower stress concentration within the
cement film)
7.A uniform type of geometry gingivally is
established with a chamfer preparation
CAST-METAL
CROWNS
METAL ONLY
PORTION OF
METAL-CERAMIC
CROWN
LINGUAL MARGIN
OF THE METAL
CERAMIC
CROWNS
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
In general, marginal widths greater than 0.3mm are referred as SHOULDERS
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett
SE. Fundamentals of fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan.299 and 325

30. SHOULDER FINISH LINE
The shoulder finish line is usually associated with
complete porcelain crowns or at times with porcelain
fixed metal crowns.
It is prepared using a flat end tapering diamond.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett
SE. Fundamentals of fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan.299 and 325

31. DISADVANTAGES
•difficult to prepare, stress
analysis,microleakage,pupl
alresponse 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
•It offers resistance
against distortion during
processing
Ibbetson RJ. Tylman'stheory and practice of fixed prosthodontics:
Edited by William FP Malone and David L. Koth. Pp. 461. 1989.
IshiyakuEuroAmerica(distributed by Gazelle Book Services,
Lancaster). Hardback

32. 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

33. 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
ADVANTAGE:-
Removes unsupported enamel, allows finishing of metal
DISADVANTAGE:-
Extends the preparation into the sulcus if used on apical margin.
INDICATIONS:-
Facial surface of a Metal-Ceramic restoration
Proximal box of Inlays and Onlays
Occlusalshoulders of Onlaysand Mandibular ¾ crown
In Shoulder margins where caries/previous restorations are present
Shillingburg HT, Hobo S, Whitsett LD,
Jacobi R, Brackett SE. Fundamentals
of fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan.299
and 327

34. 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)

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
onlaymargin
•Shoulder is already present because of destruction
by caries or presence of previous restorations
•Indicated for porcelain-fused-to-metal preparations.
INDICATIONS

36. 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

37. Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett
SE. Fundamentals of fixed prosthodontics. Quintessence
Publishing Company; 1997 Jan.299 and 323

38. RADIAL SHOULDER
It is a shoulder finish line with rounded internal
line angle.
Indicated for all ceramic crowns,facialmargin 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

39. 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

40. 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)

41. 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
gingivaltermination 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

42. 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

43. Indications
Lingual surfaces of the
mandibular teeth
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

44. CHISEL EDGE/FEATHER 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.
Formed when there is a large angle between the axial surface and the
unprepared tooth structure
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

45. James Marcum (1967) Equigingival crown margins caused least inflammatory response than supra or
subgingivalmargins
ShillinburgHT (1973) Shoulder finish line with or without a bevel have significantly less distortion than
chamfer finish lines with or without bevel
FaucherRR (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 subgingivalmargins 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

48. Effect of finish line variants on marginal accuracy and fracture
strength of ceramic optimized polymer/fiber-reinforced composite
crowns. Cho et al, J ProsthetDent 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.
The marginal adaptation of crowns with a shoulder finish line was
significantly better than crowns with a chamfer finish line before and after
cementation.
The marginal gaps were greater for the chamfer finish line specimens than in
the shoulder finish line specimens.
However, the fracture strength of the chamfer finish line specimens was
greater than that of the shoulder finish line specimens.
Related articles

49. Tooth preparations for complete crowns: An art form based on
scientific principles. Goodacre et al. J Prosthet Dent 2001;85:363
76.
Chamferfinishlinesareusedwithallmetalcrownsbecausetheyare
easytoformwithatapered,round-enddiamondinstrumentand
becausetheyaredistinct,beingreadilyvisibleonthepreparedtooth,
impression,anddie.
Chamfersalsopossessadequatebulkforrestorativerigidity,andtheir
depthissufficienttopermitthedevelopmentofnormalaxialcontours.
Therefore,chamferfinishlinesarewellsuitedforall-metalcrowns.
Authorshaverecommendedchamferfinishlinereductiondepthsof0.3
to0.5mm.

50. Finishlineshistoricallyusedwithmetalceramiccrowns:
chamfer,beveledchamfer,shoulderandbeveled
shoulder.Thicknessesbetween1.0and1.5mmforthe
porcelain-veneeredmarginalareaofametal-ceramic
crownhavebeenrecommended.
Forallceramicrestorations-shoulderfinishlinesare
recommendedforall-ceramiccrowns.Finishlinedepths
forall-ceramiccrownshaverangedfrom0.5to1.0mm.

51. 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.
The purpose of this study was to evaluate the marginal
fit of zirconia CAD/CAM ceramic crowns before and
after porcelain firing. The influence of finish line
configuration on the marginal fit was also evaluated.
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.

52. Finish-line designs for ceramic crowns: A systematic review and
meta-analysis. Chen et al. J Prosthet Dent 2019;91:554-60
Differentfinish-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 offinish-line designs on the marginal and internal adaptations of
ceramic crowns.
The marginal and internal adaptations of ceramic crowns with rounded
shoulder and chamferfinishlineswere 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

53. Influence of cervicalfinishline type on the
marginal adaptation of zirconia ceramic crowns.
comlekoglu et al, J Prosthet Dent 2018;91:554-57
The current study evaluated theeffectof different cervicalfinishline
designs on the marginal adaptation of a zirconia ceramic.
Four different marginalfinishlines (c: chamfer, mc: mini-chamfer, fe:
feather-edge and s: rounded shoulder) were prepared on phantom incisors.
Shoulder and mini-chamfer finish lines showed comparable AMO and MO
values and therefore both can be recommended in the clinical application of
zirconia crowns.
The chamfer type of finish line resulted in the highest AMO and MO values.
From a technical standpoint, although the feather-edge finish line resulted
in lower AMO and MO values, it cannot be recommended in the clinical
application of zirconia FPDs.

54. 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
ofperiodontium.

55. 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

56. 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
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.
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.
Tooth preparations for complete crowns: An art form based on
scientific principles. Goodacre et al. J Prosthet Dent 2001;85:363-
76.
The influence of finish line curvature on the marginal gap width of
ceramic copings. Asavapanumas et al. J Prosthet Dent
2013;109:226-233.