A brief presentation on: Form and Function Fundamental Curvatures Proximal Contact Area Labial And Buccal Contours Benefits of an Ideal Contact and Contour Matrix Classification of Matrixes Universal Matrix (Tofflemire Matrix) Matrix Bands Ivory Matrix No.1 Ivory Matrix No. 8 Black’s Matrices Copper Band Matrix / Soldered Band Anatomical Matrix/ Compound Supported Matrix Roll in Band Matrix (Automatrix) S-shaped Matrix Band T-shaped Matrix Mylar Strips Aluminium Foil Incisal Corner Matrix Transparent Crown Form Matrix Window Matrix Preformed Transparent Cervical Matrix Tooth Movement Rapid/ Immediate Movement Wedges Slow/ Delayed Tooth Movement Recent Advances

1. CONTACTS
&
CONTOURS
Dr. Aneetinder Kaur
PG 1st Year
Department of Conservative Dentistry & Endodontics

2. Contents
1. Form and Function
2. Fundamental Curvatures
3. Proximal Contact Area
4. Labial And Buccal Contours
5. Benefits of an Ideal Contact
and Contour
6. Matrix
7. Classification of Matrixes
i. Universal Matrix (Tofflemire
Matrix)
ii. Matrix Bands
iii. Ivory Matrix No.1
iv. Ivory Matrix No. 8
v. Black’s Matrices
vi. Copper Band Matrix /
Soldered Band
vii. Anatomical Matrix/
Compound Supported
Matrix
viii. Roll in Band Matrix
(Automatrix)
ix. S-shaped Matrix Band
x. T-shaped Matrix
xi. Mylar Strips
xii. Aluminium Foil Incisal
Corner Matrix
xiii. Transparent Crown Form
Matrix
xiv. Window Matrix
xv. Preformed Transparent
Cervical Matrix
8. Tooth Movement
9. Rapid/ Immediate
Movement
10. Wedges
11. Slow/ Delayed Tooth
Movement
12. Recent Advances

3. Form and Function
– The phrase form and function reflects a concept of interrelation of the shape or
attributes of something with its function.
– Form Follows Function
– In restorative dentistry, for example the dependent relationship between the
original biomechanical behaviour of stress concentrations in incisor teeth and
the nature of the materials used to restore these teeth is addressed. Thus the
term form not only means shape but also biomechanical attributes that
contribute to the maintenance of function.

4. Fundamental Curvatures
– 1. Proximal contact areas
– 2. Interproximal spaces (formed by
proximal surface in contact)
– 3. Embrasures (spillways)
– 4. Labial and buccal contours at the
cervical thirds (cervical ridges) and
lingual contours at the middle thirds of
crowns
– 5. Curvatures of the cervical lines on
mesial and distal surfaces
(cementoenamel junction [CEJ])
–

5. Proximal Contact Area
Area of proximal height of contour of the mesial or
distal surface of a tooth that touches the adjacent
tooth in the same arch.
According to their general shape:
1. Tapering teeth: Wide crowns & narrow cervical
region
2. Square type: Bulky, angular with little rounded
contour
3. Ovoid type: A transitional type between tapering
& square types. Surfaces are convex but
infrequently they may be concave
5

6. Labial And Buccal Contours
• at the cervical thirds (cervical
ridges) and lingual contours at the
middle thirds of crowns
• Height of Contour Area of greatest
circumference on the facial and
lingual surface of the teeth.
• Protects the gingival tissue by
preventing food impaction.

8. Benefits of an Ideal Contact and Contour
– Conserves the health of the periodontium
– Prevents food impaction
– Makes the area self-cleansable
– Improves the longevity of the proximal restorations
– Maintains the normal mesiodistal relationship of the teeth in the dental arch

9. OVERCONTOUR
• Deflects food away from gingiva
• Understimulation of supporting
tissues
• Plaque accumulation
UNDERCONTOUR
• Irritation to soft tissues
ADEQUATE CONTOUR
• Stimulation of supporting
tissues
• Healthy peridontium
9

11. Matrix
– Matrix is a device that is applied to a prepared tooth before the insertion of
the restorative material to assist in the development of the appropriate axial
tooth contours and in order to confine the restorative material excess.
– Primary function of a matrix is to restore the anatomic contours and contact
areas.
– Parts of a Matrix system involves:
• Band
• Retainer

12. MATRICING
Procedure where a temporary wall is created opposite to the axial walls,
surrounding areas of tooth structure that were lost during preparation.
Qualities of a good matrix includes:
1. Rigidity
2. Establishment of proper contour
3. Prevention of gingivalexcess
4. Convenient application
5. Ease of removal
6. Inexpensive

13. Classification of Matrixes
1. Based on mode of retention:
i. With retainer (Tofflemire matrix)
ii. Without retainer (Automatrix)
2. Based on type of band
i. Metallic non transparent
ii. Nonmetallic transparent
3. Based on type of cavity for which it is used
i. Class I cavity
a. Double banded Tofflemire (barton’s matrix)

14. ii. Class II cavity
a. Single banded Tofflemire
b. Ivory matrix No. 1
c. Ivory matrix No. 8
d. Copper band matrix
e. Automatrix
f. Anatomic Matrix
iii. Class III cavity
a. Mylar strip
b. S-shaped
iv. Class IV cavity
form
a. Mylar strip
b. Transparent crown
matrix
c. Modified S-shaped
v. Class V
a. Window matrix
b. Cervical matrix

15. Universal Matrix (Tofflemire Matrix)
• Designed by BR. Tofflemire
• Commonly used for class II restorations
• 2 types:
• Straight
• Contra-angled

16. Parts of a Retainer:

17. Advantages:
• Can be placed facially/lingually
• Retainer and band are stable when in place
• Retainer is separated easily from the band
• Retainer helps to hold the cotton roll (for isolation) in place

18. Matrix Bands
1. Uncontoured bands
• Available in 2 thickness : 0.002” and 0.0015”
• Burnishing the thinner band to contour is more difficult and less
likely to retain contours
2. Precontoured bands
• Needs little or no adjustment
• Expensive
• Difference in cost justified by lesser chair time.

19. Clinical Technique:
Shaping the Matrix
• Matrix band - shaped to achieve proper contour and contact
• Band is burnished before assembling
matrix system
• No. 26 – 28 burnisher - recommended

20. • Small round burnisher used with firm
pressure in back-forth motion until the band
is deformed occlusogingivally.
• After the band is deformed, larger egg shaped
end is used to smoothen the burnished band.

21. Preparing the retainer to receive the band
1. Larger knurled nut is turned counterclockwise
until the locking vise is 6mm from the end of
retainer.
2. Holding the larger nut, smaller nut is turned
counterclockwise until the pointed spindle is
free of the slot in the locking vise.

22. 3. Matrix band is folded end to end forming a
loop.
4. Band is positioned in the retainer so that
the slotted side of the retainer is directed
gingivally.
The band is placed through the
appropriate guide channel depending on
the location of the tooth.
Two ends of band are placed in the locking
vise, smaller nut is turned clockwise to
tighten the pointed spindle
against the band.

23. Placing the band with retainer on prepared tooth
1. Matrix band is fitted around the tooth ( 1mm apical to the gingival
margin)
2. Larger knurled nut is rotated clockwise to tighten the band slightly.
After checking gingival margins and band positioned correctly, band is
securely tightened.
3. All aspects are checked and wedges are placed.

24. Removal of the band with retainer
1. Retainer is removed from the band. Matrix is removed only after
ensuring hardening of the amalgam.
2. Index finger is placed on occlusal surface to stabilize the band as retainer
is removed.
3. No.110 pliers are used to tease the band free
from one contact point at a time.
A straight occlusal direction should be avoided
during matrix removal to prevent breaking of the
marginal ridges.
4. Wedge is left in place to provide separation of teeth while matrix band is
removed. After that it is removed.

25. Clinical Application:
• Positioned 1mm apical to gingival margin or deep enough to be engaged
by the wedge and 1-2mm above the adjacent marginal ridge.

26. Ivory Matrix No.1
• Band encircles the posterior proximal surface so
itis indicated in unilateral class II cavities.
• Band is attached to the retainer via a wedge
shaped projection.
• Adjusting screw at the end of the retainer adapts
the band to the proximal contour of the
prepared tooth.
• As adjusting screw is rotated clockwise, the
wedge shaped projections engage tooth at the
embrasures of the unprepared proximal surface.

27. Ivory Matrix No. 8
• Consists of band that encircles the entire crown of the
tooth.
• Indicated for class II cavities.
• Circumference of the band can be adjusted by adjusting
the screw present in the retainer.

28. Black’s Matrices
1. For simple cases recommended for majority of
small & medium size cavities
• Metallic band is cut so that it will extend only
slightly over buccal & lingual extensions of cavity
• Held in place by a wire or a dental floss.

29. 2. Blacks matrix with gingival extension
• Tocover gingival margin of a subgingival cavity
• Corners are rounded to prevent wounding the soft tissues.
• Held in place by a wire or a dental floss

30. Copper Band Matrix / Soldered Band
• Indicated for badly broken down teeth such as those receiving pin retained
amalgam restorations & in complex class II restorations with buccal or
lingual extensions
• Cylindrical in shape
• Band with appropriate dimensions of crown are taken and the 2 ends are
soldered.

31. • With curved scissors, the band is festooned in the cervical region to fit the
gingival contour of the tooth.
• Then with the contouring pliers, the band is contoured to reproduce the
proper shape of the contact areas.

32. Anatomical Matrix/ Compound Supported Matrix
• Most efficient means of reproducing contacts & contours
• Hand-made and contoured especially for individual teeth.
Procedure:
• Stainless steel band (0.001” – 0.002” in thickness) and 1/8 “ in width is
drawn between the handle of a pair of festooning scissors.
• Band is cut to appropriate length.

33. • Must extend beyond the cavity margins
• Wedge is placed.
• Small cones of compound material are warmed and then
forced into the buccal and lingual embrasures.
• Pressure is maintained until compound has evenly
flowed into the buccal and lingual surfaces of adjacent
teeth
• Staple is heated and forced into the compound in the
buccal and lingual embrasures.
• Restoration is then placed

34. Roll in Band Matrix (Automatrix)
• Retainerless matrix system with 4 types of bands that are designed to fit all
teeth regardless of circumference and height.
• Types:
• 3/16” (4.8mm), 0.002” thickness
• 1/4” (6.35mm), 0.002” & 0.0015” thickness
• 5/16” (7.79mm), 0.002” thickness

35. • Advantages:
• Convenience
• Improved visibility because of absence of retainer
• Ability to place the autolock loop on facial/lingual surface
• Disadvantages:
• Band is flat, difficult to burnish
• Sometimes unstable even with the use of wedges
• Development of proximal contour is difficult.

36. S-shaped Matrix Band
• For class III, class II and with facial/lingual extensions of
class V
• Matrix band of 0.001” – 0.002” is used
• Mirror handle is used to produce the S-shape in the strip
• Strip is contoured in its middle part with contouring pliers
to create desired form for the restoration
• Compound material is used to hold the band in position in
the facial and lingual aspect and also in the gingival aspect.

37. T-shaped Matrix
brass/ stainless steel matrix• Premade T-shaped
bands
• Longer arms of the matrix is bent to encompass the
tooth circumferentially and to overlap the short
horizontal arm of ‘T’
• This section is then bent over the long arm, loosely holding it in place.
• Wedges can be used to stabilize the matrix.

38. Indications:
• Class II cavities involving 1 or both proximal surfaces of a posterior
tooth
Advantages:
• Simple
• Inexpensive
• Rapid
• Easy to apply
Disadvantages:
• Flimsy in structure and not stable

39. Mylar Strips
• For composite restorations in Class III and Class IV cavities.
Procedure
• Mylar strip is burnished with the end of an
instrument handle to produce a belly.
• This produces a normal contour of the
proximal surface of the teeth.

40. • Strip is then cut to place the belly where the
contact is desired.
• A wedge is trimmed and applied to hold the
strip in place.

41. • Lingual aspect of strip is secured with index
finger
• Facial portion is reflected away for access.
• Following insertion of composite, matrix
strip is closed and material is cured through
strip.

42. Aluminium Foil Incisal Corner Matrix
• Stock metallic matrices shaped according to proximo-incisal corner and
surfaces of anterior teeth.
• Cannot be used for light cured resin materials.

43. Procedure:
• A corner matrix closest in size and shape of teeth is selected.
• Trimmed gingivally to coincide with gingival architecture and covers
gingival margin of preparation.
• It is shaped with fingers until it fits mesio-distal and labio-lingual
dimensions of tooth.
• Wedge is placed
• Apply the restorative material
• Tighten the wedge and wipe off excess material.

44. Transparent Crown Form Matrix
• Stock plastic crowns
• Can be used for light cured resin material
• For Class III and Class IV
Procedure:
• Appropriate size is selected that matches closely with the inciso-
gingival dimension of the tooth to be restored.
• Trim the crown gingivally to match with the gingival architecture.

45. • Should be perforated at the incisal angle.
• The prepared tooth is partially filled with the
restorative material while the matrix is completely
filled.
• Placed over the prepared tooth surface.
• Excess material is wiped off, held under the finger
pressure.

46. • Indications:
• Large bilateral/unilateral class IV cavity
• Oblique fractures of anterior teeth
• Advantages:
• Easy to use
• Good contours can be established
• Disadvantages:
• Time consuming
• Expensive

47. Window Matrix
• For class V cavities
• Formed using either a Tofflemire matrix or copper band.
Procedure:
• A window is cut slightly smaller than the
outline of the cavity.
• Wedges are placed, mesially & distally to
stabilize the band.

48. Preformed Transparent Cervical Matrix
• For use with light cured resin material or RMGIC
• Matrix must be held in place while the restoration
is setting
• Indications:
• Class V restorations with composite or RMGIC
• Advantages:
• Provides good contour for restorations
• Disadvantages:
• Expensive

49. Tooth Movement
• Act of separating the involved teeth from each other, bringing them
closer to each other or changing their spatial position in one or more
dimensions.

50. rotated teeth to their indicated
Objectives:
• To bring drifted, tilted or
physiological positions
not amenable to closure by• To close space between teeth
restoration
• Tomove teeth to another location
• Tomove the teeth occlusally or apically to make them restorable.
• To move teeth from a non-functional or traumatically functional
location to a physiologically functional one.

51. • Tomove teeth to a position so that when restored, they will be in a
most aesthetically pleasing situation.
• To move teeth in a direction and to a location to increase the
dimensions of available structure for resistance and retention form.
• Tocreate sufficient space for thickness of matrix band.

52. 52
Tooth Movement
Rapid / Immediate Slow / Delayed

53. Rapid/ Immediate Movement
• Mechanical type of separation
• Creates either proximal separation at the point of
separator’s introduction and/or improved closeness of
proximal surface of opposite side.
– Indications:
• As preparatory to slow movement
• Tomaintain the space gained by slow movement

54. Methods
1. Wedge Method
• By insertion of a pointed wedge
shaped device between the teeth
• The more the wedge moves facially
or lingualy, greater is the separation.

55. 2. Elliots Separator
• Indicated for short duration separation
that does not necessitate stabilization
• Useful in examining proximal surfaces in
finalpolishing of restored contacts
• Components
• Two Holding Jaws
• Tightening Screw
• Works on the Wedge Principle
• Also known as Crab Claw Separator

56. Wood/ Plastic Wedges
• Used in both tooth separation for preparation and restoration
• Triangular shaped wedges (wood/synthetic resin)
• Cross-section base of triangle will be in contact
with interdental papillae.
• Two sides of the triangle should coincide with
the corresponding 2 sides of the gingival
embrasure.
• Apex must coincide with the gingival start of the
contact area.

57. Functions
• Hold the matrix band in position
• Slight separation of the tooth
• Provides space for placing matrix band
• Prevent gingival overhang
• Stabilizes matrix and retainer
• Assure close adaptability of matrix
band to the tooth
• Protect interproximal gingiva from
unexpected trauma
• Types:
• Wooden
• Plastic
• Elastic
• Transparent
• Medicated wedges
• Shape:
• Triangular
• Round
• Trapezoidal

58. Wedging Method
• Location : Gingival embrasure just beneath the contact area.
• Selection : Depending upon the clinical situation.
Wooden wedges can be trimmed using a knife or scalpel blade
to produce a custom fit.
• Placement : From the lingual embrasure which is normally larger in size.
But if it interferes with the tongue it may be placed from the
buccal side.
• Length
: so that it does not irritate the tongue or the cheek.
After placement the wedge should be firm and stable.

59. Wedging techniques
1. Single wedge technique
• Single wedge is placed in the gingival
embrasure
2. Piggyback wedging
• A second wedge is placed on top of the first
wedge to wedge adequately the matrix against
the margin
• Indicated for patients whose interproximal
tissue level has receded.

60. 3. Double wedging technique
• Here, 2 wedges, one from the facial embrasure and the other from the
lingual embrasure are used.
• Used when proximal box is wide faciolingually.
• Should be used only if the middle 2/3rd of the
proximal margins can be adequately wedged.

61. 4. Wedge wedging technique
• Used in cases when there is a gingival concavity as in the case of a
fluted root.
• Inorder to wedge a matrix band tightly against such a margin, a second
wedge is inserted between the first wedge and the band.

62. • Rounded toothpick wedge is usually the wedge of choice with conservative
premolar boxes.
• Triangular wooden wedges are more recommended since:
• Easy to trim and adapt well to tooth surface
• When properly shaped, they remain stable during condensation
• Absorb moisture and swell to provide adequate stabilisation
• Wooden wedges can be cut from toothpicks

63. Light Transmitting Wedges
• Plastic wedges which are transparent and have a light reflecting core.
• Used with transparent matrices
• Can transmit 90 – 95% of the incident light : drawing the curing light to
the gingival margins of the restoration
• Provides better marginal adaptation at the cervical area of the class II
composite resin restorations

64. Prewedging
• The procedure of inserting a wedge between the interproximal surfaces of
two adjacent teeth prior to cutting a cavity involving a proximal wall.
Purpose is to achieve some tooth separation such that, after restoration, the
teeth will return to their original position and a more positive tooth contact
area will be achieved.

65. Error’s with wedge placement
• If wedge is placed more occlusal to the gingival
margin, creates abnormal concavity in the proximal
surface of the restoration.
• If wedge is for apical to gingival margin, band will not
be held tightly against the gingival margin & creates
gingival overhangs in the restorations.
• Tightness of the wedge is tested by pressing the tip of an explorer firmly
several points along the middle 2/3rd of the gingival margin against the
matrix band.

66. 2. Traction method
• Done with mechanical devices which engage the proximal surfaces of the
teeth to be separated by means of holding arms.
• Non-Interfering true separator
• Ferrier double-bow separator

67. Non-Interfering true separator
• Indicated when continuous stabilized separation is required.
• Advantage:
• Separation can be increased or decreased after stabilization
• Device is non-interfering

68. Procedure:
• Apply the jaws closest to the bow against the tooth to be operated
upon.
• Apply a piece of softened compound to teeth under separator.
• A wrench used to move the jaws over the approximating tooth.
• The Nut on the facial side moved first until the jaw touches the
surface needed, then that of lingual side.
• Repeat the adjustment until desired amount obtained.

69. Ferrier double-bow separator
• Separation is stabilized throughout the dental operation.
• Advantage :
• Separation is shared by the contacting teeth and not at the
expense of one tooth

70. Procedure:
• Four arms are adjusted so each will hold a corner of proximal
surface of contacting teeth.
• Arms will be gingival to contact area.
• Wrench applied to labial and lingual to make desired separation.

71. Slow/ Delayed Tooth Movement
Indications:
• When teeth have drifted and/or tilted considerably, rapid
movement of the teeth to proper position will endanger the
periodontal ligaments.
• Therefore slow tooth movement over weeks will allow
proper repositioning of teeth in physiological manner.
Methods:
• Separating wires, Elastics
• Oversized temporaries
• Orthodontic appliances

72. Separating Wires
• Thin pieces of wire are introduced into the gingival contact area
• It is then wrapped around the contact area.
• The 2 ends are then twisted together to create separation not to exceed
0.5mm
• Wires are tightened periodically to increase the separation.

73. Oversized Temporaries
• Resin temporaries are oversized mesio-distally to achieve slow
separation
• Resin added periodically to increase the amount of separation not to
exceed 0.5mm

74. Orthodontic Appliances
• Fixed appliances – most effective and predictable method
• Removable appliances can also be used – requires longer treatment

75. Recent Advances
Precontoured Sectional Matrix Bands
Contact Rings
Contact Matrix

76. Benefits with the Sectional Matrices
and Contact Rings
• Ease of use and good visibility.
• ensures optimal contact areas and
embrasures.
• Less tension on the teeth
• greater comfort for the patient
• No need for pre-wedging.
• Gingival adaptation good.
Problems with early contact rings
• Ring collapse
• displacement in case of wide proximal
boxes.
• Ring stacking that is, placing one ring
over the other in case of MOD
restoration is a problem.
• Contact rings are made of stainless
steel, loss of their springiness over
time.

78. Fender Wedges
• For protection and separation during tooth
preparation.
• Combination of a steel plate and a plastic wedge.
• Inserted into the inter dental space it provides a
protector for the tissue and separates the teeth,
simplifying the following application of a matrix.
• Can be applied buccally or lingually for optimal access
and vision.

79. Conclusion
• Proper restoration of the anatomical landmarks is important for enhancing
the longevity of restorations as well as to maintain the occlusal health and
harmony.
• Matricing is a vital step during the placement of different restorations.
• Selection of the matrix should be based on its ease of use and efficiency to
provide the optimum contacts and contours..
• The dentist should select the right method according to the needs of
individual case.

80. Operative Dentistry – MA Marzouk
Art & science of operative Dentistry – Sturdevants (5th edition)
Art & Science of Operative Dentistry – Sturdevants (South Asian
Edition)
Dental Anatomy, Physiology & Occlusion – Wheeler’s (9th Edition)
References

81. Thank You