overall analysis of finish line

1. 1
MOHD.SIBGHATULLAH KHATIB
1ST PG STUDENT
GOOD MORNING
SUCCESS is not just a measure of how big
you can DREAM…
It is also a measure of how much you can
DO

2. 2
FINISH LINE

3. Contents
• Introduction
• Definition
• Principles of tooth
preparation
• Finish lines for
Extracoronal
restorations
Full veneer crown
Complete cast crown
Metal - ceramic crown
All-ceramic crown
– Porcelain veneer crown
 Partial veneer crown
 Onlays
• Finish lines for
Intracoronal restorations
Inlays
Amalgam
Direct filling gold
Composites
Glass ionomer cement
• Conclusion
3

4. • One of the basic tenets of restorative dentistry is to conserve
as much tooth structure as possible consistent with the
mechanical and esthetic principles of tooth preparation.
4
Introduction
Contemporary Fixed Prosthodontics 3rd edition

5. Introduction
• Restoration can survive in the biologic environment of
the oral cavity only if the margins are closely adapted to
the finish line of the preparation
5
Contemporary Fixed Prosthodontics 3rd edition

6. According to Schwartz
• Refers to the border of the preparation where the prepared
tooth structure meets the unprepared surface of the tooth.
According to Rosenstiel
1. A line of demarcation
2. The peripheral extension of a tooth preparation
3. The planned junction of different materials
4. The terminal portion of the prepared tooth.
6
Definition

7. Principles of tooth preparation
1. Preservation of tooth structure
2. Retention and resistance
3. Structural durability – Marginal geometry
4. Marginal integrity – Marginal adaptation
5. Preservation of the periodontium – Margin placement
7
Herbert T. Shillingburg 3rd edition

8. Preservation of tooth structure
• Avoide excessive destruction
• Design restoration to reinforce and protect remaining
enamel and dentin
8
Herbert T. Shillingburg 3rd edition

9. Retention & Resistance
• Retention prevents removal of the restoration along
the path of insertion or long axis .
• Resistance prevents dislodgement of the restoration
by an apical/oblique forces
9
Herbert T. Shillingburg 3rd edition

10. 10
Taper
Freedom of displacement
Herbert T. Shillingburg 3rd edition

11. 11
Length
Substitution of internal feature
Path of insertion
Herbert T. Shillingburg 3rd edition

12. Structural durability
• Adequate space created by tooth preparation
12
Occlusal reduction Axial reduction

13. Marginal integrity
• Margins of restoration must be closely adapted to finish line
of preparation
• Configuration of the preparation finish line dictates the shape
of restorative material in the margin of the restoration
13
To bevel….. ….Not to bevel
Herbert T. Shillingburg 3rd edition

14. Finish line in extracoronal restoration
Chamfer
Heavy chamfer
Shoulder
Sloping shoulder
Radial shoulder
Shoulder with bevel
Knife edge/ Feather edge
Chisel edge
14
Contemporary Fixed Prosthodontics 3rd edition

15. Extracoronal restorations - Finish line configurations
• Finish line classification according to width
Marginal width less than 0.3mm - Knife-edge/ feather edge
Marginal width upto 0.3mm – Chamfer
Marginal width greater than 0.3mm - Shoulder
15
A.J. Hunter JPD 1990;64

16. Chamfer
• GPT- A Finish line design for tooth preparation in
which the gingival aspect meets the external axial
surface at an obtuse angle.
• TYLMANN (1965): Concave extra coronal finish
line that provides greater angulation than a knife-edge
and less width than a shoulder.
16

17. 17
Advantage Disadvantage Indication
•Distinct margin
•Adequate bulk
•Easier control
•Care needed to avoid
unsupported lip of
enamel
•Cast metal
restoration
•Lingual margin of
metal ceramic
Bur
Round end taper Round end taper

18. Heavy chamfer
 Provides 90 degrees cavosurface angle with a large
radius rounded internal angle.
 A bevel can be added to the heavy chamfer for use with
metal restoation.
18
Herbert T. Shillingburg 3rd edition

19. 19
Round end taper
Bur
Advantage Disadvantage Indication
•Better support for a
ceramic crown
•Unskilled operator
can create an
undesirable fragile
“lip” of enamel at
cavosurface
•Ceramic crown
•With bevel metal
crown

20.  Finish line of choice for all-ceramic crown
 Wide ledge provides resistance to occlusal forces
 Produce the space for healthy restoration contours and
maximum esthtetic
20
Shoulder
Herbert T. Shillingburg 3rd edition

21. 21
•Advantage •Disadvantage •Indication
•Bulk of restorative
material
•Less conservative of
tooth structure
•Stress concentration
at 90 degree internal
angle of the finish
line, hence conducive
to coronal fracture
•Facial magin of
metal ceramic crowns
•Complete ceramic
crown
Flat end taper
Bur

22.  Modification of shoulder finish line
 Support for ceramic restoration is good
22
Herbert T. Shillingburg 3rd edition
Radial shoulder
•Advantage •Disadvantage •Indication
•Stress concentration
lesser than the classic
shoulder
•Less conservative of
tooth structure
•Facial magin of metal
ceramic crowns
•Complete ceramic
crown

23. 23
Flat end taper End cutting carbide
finishing bur
Modified bine-angle
chisel
Bur

24. 24
Herbert T. Shillingburg 3rd edition
Shoulder with bevel
•Advantage •Disadvantage •Indication
•Bulk of material •Less conservative,
extend peraparation
apically
•Facial magin of
posterior metal
ceramic crowns with
supragingival margin
 Uses –
• Gingival finish line on the proximal box of inlays and onlays
• Occlusal shoulder of onlays and mandibular three-quarter crowns
• Finish line for extremely short walls
• More destruction of tooth - NOT USED routinely for full veneer
restorations

25. A 120-degree sloped shoulder margin used as an alternative to the
90-degree shoulder for the facial margin of a metal-ceramic crown.
 Reduces the possibility of leaving unsupported enamel
Provides sufficient bulk to allow thinning of the metal framework
to a knife-edge for acceptable esthetics.
25
Sloping shoulder
•Advantage •Disadvantage •Indication
•Bulk of material •Less conservative of
tooth sturcture
•Facial magin of metal
ceramic crowns
Contemporary Fixed Prosthodontics 3rd edition

26.  The ultimate finish line that permit an acute margin
of metal
 Uses –
• Lingual surface of mandibular posteroior teeth
• Very convex axial surfaces
• Surface towards which tooth is tilted
 Disadvantage –
• Axial reduction may fade out
• Thin margins difficult to wax and cast
• Overcontoured restorations
26
Herbert T. Shillingburg 3rd edition
Knife edge/ Feather edge

27. Chisel edge
• A variation of the featheredge,
• Formed when there is a larger angle between
the axial surfaces and the unprepared tooth
structure.
• Associated with an excessively tapered
preparation
27
Contemporary Fixed Prosthodontics 3rd edition

28. 28
A. Featheredge, B. Chisel, C. Chamfer, D. Bevel, E. Shoulder, F. Sloped Shoulder, G. Beveled
shoulder Contemporary Fixed Prosthodontics 3rd edition

29. • Shoulder margins provide good seat but a
comparatively wider marginal seal
• Chamfer, long chamfer and feather edge margin
provide superior sealing of the margins despite poor
seat.
30
Journal of Clinical and Diagnostic Research. 2015 Aug, Vol-9(8 )

30. • Both ZZ and E copings presented better marginal fit on
shoulder preparations than chamfer preparations.
31
European Journal of Dentistry April 2012 - Vol.6

31. Preservation of the periodontium
• Margins as smooth as possible
• Kept clean by the patient
• Supragingival placement of finish lines whenever
possible!
• Subgingival finish lines 2.0 mm from alveolar crest
32
Herbert T. Shillingburg 3rd edition

32. • The biologic width is defined as the dimension of the soft
tissue, which is attached to the portion of the tooth coronal
to the crest of the alveolar bone
• Biologic width (EA + CTA) dimensions -
– Anterior teeth 1.75mm
– Premolars 1.97mm
– Molars 2.08mm 33
Biologic width
J Clin Periodontol 2003; 30: 379–385

33. 35
Margin placement
Supragingival margin Equigingival margins Subgingival margin
Placed in non-esthetic
area
At the crest of the
marginal gingiva
Below the gingiva
Least impact on
periodontium
More impact on the
periodontium
Greatest biologic risk
More plaque retentive May violate gingival
attachment apparatus

34. Margin placement guidelines
36
If the sulcus probes 1.5mm or less, place the
margin 0.5mm below the gingival crest
If probing depth more than 1.5mm – place the
margin half the depth of the sulcus below the
crest
If probing depth more than 2.0 mm –
Gingivectomy is advocated
Indian Journal of Clinical Practice, Vol. 23, No. 11, April 2013

35. 37
Orkin et al
Silness
Indian Journal of Clinical Practice, Vol. 23, No. 11, April 2013
Subgingival restorations
Bleeding
Gingival recession
Supragingival position of the crown margin
Margins below the gingival margin

36. Finish line exposure
• Mechanical
– Copper tube/band
– Rubber dam
• Chemomechanical (retraction cord)
– Caustic chemicals – sulfuric acid, trichloracetic acid,
negatol, zinc chloride
– Racemic epinephrine
– Aluminium chloride, alum, aluminium sulfate, ferric
sulfate
• Rotary curettage/ gingettage
• Electrosurgery
38

37. 39
MOHD.SIBGHATULLAH KHATIB
1ST PG STUDENT
GOOD MORNING
Beginning well is a momentary thing;
finishing well is a life long thing.

38. Extracoronal restoration - Full veneer crowns
40
All ceramic crown
Full metal crown
Metal ceramic crown

39. Full veneer crowns
41
Full metal

40. Metal ceramic crown
Full veneer crown
42

41. Metal ceramic crown
Full veneer crown
43

42. Full veneer crown
44
ALL CERAMIC CROWN

43. Partial veneer crowns
45

44. Porcelain laminate veneers
46

45. 47
A conservative method of
restoring the -
Discolored
Pitted
Fractured anterior teeth.

46. According to sturdavent
– PLV can be classified into
1. Partial veneers
2. Full veneers
a) Window preparation
b) Incisal lapping
48

47. Windows Feather Bevel Incisal overlap
Four basic preparation designs for the incisal edge
reduction.........
Incisal edge reduction
Walls et al. Crowns and other extra-coronal restorations: Porcelain laminate veneers :British
dental journal 2002;193 : 2:73-81

48. Cervical finish line
Long chamfer with about a 0.4 mm maximum depth.
• Proximal finish line
– Incisal third of the tooth - not to extend beyond the
contact point
50Walls et al. Crowns and other extra-coronal restorations: Porcelain laminate veneers :British
dental journal 2002;193 : 2:73-81

49. Finish lines for intracoronal restorations
51

50. Enamel pattern
Occlusal surface Axial surface
52
Clincal significance
Cavity wall angulation
Convergent
Depending
upon the
buccolingual
width
Divergent
Parallel
Cavity prepared
Amalgam
BevelsCast gold

51. Noy’s criteria
53
1. Enamel must be supported by sound dentin
2. The enamel rod which form the cavosurface angle must
have their inner end resting on sound dentin
3. Enamel rods forming cavosurface angle should be
covered with restorative material
4. Angular cavosurface angles should be trimmed
M.A Marzouk

52. 54
Cavosurface margin Cavosurface angle Cirumferential tie
Terminologies

53. Bevels
Plane of a cavity wall/ floor directed away from
the cavity preparation
Any angle other than 90o between a tooth cut and
a cavity wall in the preparation of the tooth cavity
55

54. Classification
1. Partial bevel
2. Short bevel
3. Long bevel
4. Full bevel
5. Counter bevel
6. Hollow ground (concave) bevel
56

55. Partial bevel
• Not more than two third the thickness of enamel
• Used to trim weak enamel rods at the margins
Short bevel
• Entire enamel wall but not dentin
• Used for class I alloys – type I and II alloys
Long bevel
• Entire enamel+1/2 of dentinal wall
• Used for first three classes of cast alloys
• Preserves internal box form of resistance and
retention feature
Full bevel
• Entire enamel and dentin
• Resistance and retention form hampered
• All classes of cast alloys 57

56. Hollow ground (concave) bevel
• Concave form
• For base metal alloys and castable ceramics
• Improves castability
• Provides bulk
Counter bevel
• Cusp capping
• Opposite to axial cavity wall on facial
or lingual surfaces
58

57. Bevel with different restoration
• Amalgam ………..
• Composite …..
59

58. Amalgam
60
Cavosurface angle Gingival margin
Cavosurface Margins in Direct restorations

59. Margins in Direct tooth coloured
restorations
• General concepts
1. Minimal extension
2. Pulpal and/or axial walls of varying depth
3. Enamel bevel
4. Butt joint on root surfaces
5. Tooth preparation walls must be rough
61

60. Direct tooth coloured restoration
• Five designs of tooth preparations for composite
restorations are..........
1. Conventional
• Similar to amalgam cavity preparation designs
2. Beveled conventional
• Similar to conventional but bevels given
3. Modified
• Scooped out design
4. Box only
• Proximal caries
5. Slot preparation designs.
62

61. Anterior composite restoration
63
Class III composite
Beveled conventional class III design

62. 64
Anterior composite restoration
Bevelled conventionalClass IV restoration

63. Anterior composite restorations
According to Albers
• Class IV cavity preparations
– Chamfer design
– Bevelled margins
1. Chamfer design
– 1mm long or half the length of fracture
– Most durable restorative margins
– Stair stepping – better esthetics
65

64. Anterior composite restorations
• Bevelled margins
– Alternative to stair step chamfer
– 2-3mm bevel
– Better esthetics
– Bevels in a curve better than scalloped margins
– Drawback
• Margins not as durable as chamfer
• Chipping
66

65. Anterior composite restorations
67

66. Anterior composite restorations
68
Class V restoration
Conventional Bevelled conventional

67. Posterior composite restoration
69
Enamel margin design
90 degree exit 45 degree bevel
Concave bevel (chamfer)

68. • Internal bevel at the cervical cavosurface of class
2 composite restoration reduced marginal
microleakge as compared to conventional butt
joint
70
JIOH, October 2010, Volume 2 (Issue 3)

69. Margins in direct gold restoration
71
• Cavosurface margin bevel –
Partial bevel
Width – not more than 0.2mm
30-40 degrees metal margin
Gingival margin bevelled if on enamel
Should include atleast 1/4th enamel wall
Wedelstaedt chisel used
• Allows coverage of the enamel margin with the
restorative material

70. 72
MOHD.SIBGHATULLAH KHATIB
1ST PG STUDENT
GOOD MORNING
Don’t stop when you are tired.
STOP when you are DONE……

71. Margins in Indirect restorations
73

72. 74
AdvantageIndication
•Large restoration
•Endodontically treated
teeth
•Teeth at risk for fracture
•Removable
prosthodontic abutment
•Strength
•Biocompatibility
•Low wear
•Control of contour and
contact
Contraindication
•High caries rate
•Young patient
•Esthetics
•Small restoration
Disadvantage
•Number of appointment
•Temoprary
•Cost
•Technquie sensitive
•Splitting force

73. Cast metal inlay
• It is as intracoronal cast restoration replacing one
or more, but not all of the cusps fabricated
extrorally using direct or indirect wax pattern.
75

74. 76

75. Cast metal inlay
77
Bevel

76. • Basic part of circumferential tie
• Similar to long bevel
• Angulations of 45 degrees to inner dentinal wall
Flare
78
Primary

77. • Function -
Same as bevels
Brings facial and lingual margins to self –
cleansable areas
• Indication -
Normal contacts
Minimum extension of caries in the
buccolingual dimension
79

78. • Flat plane superimposed peripherally to a
primary flare
• Prepared solely in enamel, sometimes includes
dentin
• No definite angulation – depends on
involvement and extent
• 40 degrees marginal metal and 140 degrees
marginal enamel desirable
80
Flare
Secondary

79. Indications
Indirect wax pattern
Broad contact areas
Wide extension of caries buccolingually
Overcome undercuts in the cervical aspect of facial and
lingual proximal walls in ovoid teeth
Extends margins into embrasures
Stronger enamel margin produced
40 degree marginal metal
81
Function

80. • Secondary flare omitted in mesiofacial
proximal wall of –
Maxillary premolars
Maxillary molars
• Burs No. 8862/ 169 L / paper discs
82

81. Tooth coloured inlays
• Ceramic and Composite inlays
– Facial, lingual, and gingival margins of the
proximal boxes - clear the adjacent tooth by at
least 0.5 mm
– 90-degree cavosurface margin desired
– Minimal gingival margin extension - margins in
enamel preferred for bonding and impression
84

82. Margins for onlay
85

83. Onlay
• According to sturdavent
– The cast metal onlay by definition caps all of the
cusps of a posterior tooth and can be designed to
help strengthen a tooth that has been weakened by
caries or previous restorative experiences.
86

84. Onlay
87
Counter bevel

85. Onlay
88
Collar
Skirt

86. Summary
89
Extracoronal restoration
Intracoronal restoration

87. 90
Restoration Finish line
design
Finish Line
dimension
Purpose
Full metal Chamfer, knife-
edge, shoulder
with bevel
0-1mm Marginal integrity,
structural
durability

88. Restoration Finish line
design
Finish Line
dimension
Purpose
Metal ceramic Labially
shoulder,
shoulder with
bevel, sloping
shoulder
Lingually
Chamfer
Labially
1.2mm
Lingually
0.5mm
Removes
unsupported
enamel, structural
durability,
marginal integrity
91

89. 92
Restoration Finish line
design
Finish Line
dimension
Purpose
All ceramic Shoulder,
heavy
chamfer,
rounded
shoulder
0.7 - 1mm Marginal integrity
Structural
durability
Esthetic

90. 93
Restoration Finish line design Finish Line
dimension
Purpose
Partial
veneer
crown
Chamfer 0-1mm Marginal integrity,
Structural durability
Proximal flare Marginal integrity
Occlusal/incisal
offset
Structural durability
Buccal/incisal
bevel
Marginal integrity,
Remove
unsupported enamel
Occlusal shoulder 1mm Structural durability

91. 94
Restoration Finish line
design
Finish Line
dimension
Purpose
Porcelain
laminate veneer
Long chamfer 0.3-0.5mm Marginal integrity,
conserves tooth
structure, better
etching

92. 95
Restoration Cavosurface margin
design
Margin
features
purpose
Amalgam
Butt joint 90 degrees Strongest
margin for
amalgam
Gingival finish line
At Gingival third-
beveled
At Middle third/root
surface – no bevel
15-20 degrees Remove
unsupported
enamel

93. 96
Restoration Cavosurface margin
design
Margin features Purpose
Anterior
Direct
Composite
Restoration
Conventional – no
bevel
90 degrees
margin
Lesion on
root- no
enamel to
bevel
Bevelled
conventional
(partial , long)
45 degrees
0.25-0.5mm
Increased
surface area
for etching
and bonding
According to Sturdavent

94. 97
Restoration Cavosurface margin
design
Margin features Purpose
Anterior
direct
composite
restoration
Chamfer
1mm or half the
length of defect
Half the depth of
enamel
Durability
Bevelled (scalloped) 2-3mm Esthetics
According to Albers

95. Restoration Cavosurface
margin design
Margin
features
purpose
Occlusal
Butt joint
Bevel (partial,
long)
90 degrees
45-70 degrees
0.25 – 0.5mm
Enamel rod ends
exposed
Conserves tooth
structure
Better sealing
Proximal Long bevel 0.5mm wide
45 degrees
1. Increased surface
area for etching and
bonding
2. Margins placed in
accessible areas
3. Reduced marginal
leakage
98
Posterior direct composite restoration

96. 99
Restoration Cavosurface
margin design
Margin
features
purpose
Gingival
Partial bevel
Butt joint ....
close to CEJ
1/3rd – ½ the
enamel wall
90 degrees
Better sealing
Exposes enamel rod
ends internally
Better sealing than
butt joint
Direct gold
restoration
Partial bevel <0.2mm 30-40 degrees metal
margin
Posterior direct composite restoration

97. 100
Cast metal
inlay
Bevel
Occlusally Gingivally
Flare
Primary Secondary
Partial
bevel

98. 101
Restoration Cavosurface
margin design
Margin features Purpose
Cast metal
inlay
Occlusally –
• partial bevel
• Steep cusp –
no bevel
Width – 1/4th the
depth of respective
wall
140-150 degrees
cavosurface margin
• 30-40 degrees
marginal metal –
burnishible, lap
joint
• Strongest
cavosurface
margin
INDIRECT RESTORATION

99. 102
Restoration Cavosurface
margin design
Margin features purpose
Cast metal
inlay
Gingivally –
• Partial bevel
• Reverse bevel –
sufficient gingival
floor width
Width - 0.5-1mm
150 degrees
cavosurface
margin
• 30-40 degrees
marginal metal –
burnishable
•Minimizes cement
line
• Strongest
cavosurface margin
• Removes
unsupported enamel
•Resistance to
dislodgement against
occlusal forces
INDIRECT RESTORATION

100. 103
Restoration Cavosurface
margin design
Margin features Purpose
Cast metal
inlay
Primary flare 45 degrees to
inner dentinal
wall
similar to long
bevel
30-40 degrees
marginal metal
•Increases retention
•Self-cleansable
areas
Secondary flare Placed entirely in
enamel
sometimes dentin
No particular
angulation
• Acute marginal
metal
• Strong enamel
margins
•Extends margins to
embrasures
INDIRECT RESTORATION

101. 105
Restoration Cavosurface
margin design
Margin features Purpose
Tooth
coloured
inlay
Bevels and
flares – hollow
ground
90 degrees butt
joint
• Material bulk
• Better Resistance
to stresses
Gingival
margin -
hollow ground
Or no bevel –
middle
third/cementum
90 degrees butt
joint
• Removes
unsupported
enamel
• Material bulk
• Better Resistance
to
stresses
INDIRECT RESTORATION

102. Restoration Margin design Margin features purpose
Cast metal
onlay
Counter bevel
Facial and lingual
margin of reduced
cusp
Structural durability,
marginal integrity,
retention, stress
distribution 30-40
degrees marginal
metal
Just gingival to tip
and ridge crests
Flat sometimes
partial bevel given if
unsupported enamel
remains
Increased resistance
and retention
Conservation of tooth
structure
Gingival bevel and
secondary flares
similar to inlay
106
INDIRECT RESTORATION

103. Restoration Margin design Margin features purpose
Tooth
coloured
onlays
Cusp protection –
capping
Exaggerated
hollowground
counterbevel –
occlusal table to
facial termination
of the preparation
Shoulder – 1mm
Increased
retention
Structural
durability
Gingival margins
and proximal
margins – same as
tooth coloured
inlays
107
INDIRECT RESTORATION

104. Conclusion...
• While choosing a configuration of finish line for
extracoronal restoration one must consider the
advantages and disadvantages of various finish
lines
• While deciding about the placement of the finish
line , periodontal health and esthetics have to be
equally weighed
• For the intracoronal restoration, type of
restorative material being used and the enamel
pattern play an important role
108

105. Conclusion...
• For the restorative materials with low tensile
strength like amalgam and ceramics, butt joint
is preferred
• Bevels and flares are used for metals because
of their property of burnishability
• Angle and width of bevels and flares also
require careful placement
109

106. Conclusion...
“We shall neither fail nor falter , we shall not
weaken or tire, give us the tools and we will
finish the job”
- Winston Churchill
• Hence every effort should be made to design
and prepare the marginal peripheries to create
the most favourable relationship with the
restoring casting and luting cement.....
110

107. References
• Contemporary Fixed Prosthodontics 3rd edition
• Herbert T. Shillingburg 3rd edition
• A.J. Hunter JPD 1990;64
• Journal of Clinical and Diagnostic Research. 2015 Aug, Vol-
9(8 )
• European Journal of Dentistry April 2012 - Vol.6
• Indian Journal of Clinical Practice, Vol. 23, No. 11, April 2013
• Walls et al. Crowns and other extra-coronal restorations:
Porcelain laminate veneers :British dental journal 2002;193 :
2:73-81
• Sturdavent 4th edition
• JIOH, October 2010, Volume 2 (Issue 3)
• J Appl Oral Sci. 2012;20(2):174-9 111

108. 112