Contacts & Contours

Dr. Nithin Mathew – Contacts & Contours
Contents
• Introduction
• Contacts
• Contours
• Proximal Contact Area
• Embrasures
• Marginal Ridges
• Procedures for formulation of proper contacts and contours:
• Toothmovement
• Rapid
• Slow
3

• Matricing
• Classification
• Types
• Recent Advances
• Conclusion
• References
4

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• Presence of proper contacts & contour is important to maintain stability &
occlusal harmony.
• A thorough knowledge of the contacts & contours of various teeth is
mandatory for understanding:
• Predisposing factors of proximal caries like faulty interrelationships.
• Significance of marginal ridges, embrasures for re-establishing the
form and function of restored teeth.
• Periodontal aspect & health of the tooth to be restored.

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• Benefits of an ideal contact & contour:
1. Conserves the health of peridontium
2. Prevents food impaction
3. Makes area self cleansable
4. Improves longevity of proximal restorations
5. Maintains normal mesiodistal relationship of the teeth in the dental
arch

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• Role of a dentist is to establish the ideal extension so as to perform
optimal functions, maintaining the integrity and longevity of individual
tooth.

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Food we consume moves in 3 different directions:
• Occlusal surfaces
• Contact & Gingival embrasures
• Facial & Lingual sulcus

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• Any decay occurring on the proximal surface is mainly due to faulty
interrelationship between
• Contact Areas
• Marginal Ridges
• Embrasures
• Gingiva.

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• Time of eruption: only contact point
• Proximal Contact Point Proximal Contact Area

Proximal Contact Area
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• 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, 3 types:
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

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CONTACT TAPERING SQUARE OVOID
Between
Incisors
Contacts starts at incisal
ridge & labial, labiolingually
Starts at incisal ridge & incline
with it labiolingually
Slightly lingual to incisal ridge
Mesial contact start at 1/4th of
crown incisogingivally
Distal contact start 1/3rd to ½
of crown incisogingivally
Canine Mesial: incisal ridge
Distal: middle third
Very angular
Close to incisal ridge incisally Close to incisal ridge incisally
Bicuspids Buccal periphery is almost at
bucco-axial angle
Buccal periphery more towards
bucco-axial angle
Buccal periphery at junction
of buccal & middle third
Occlusal periphery at
junction of occlusal & middle
3rd of crown
Occlusal periphery at occlusal
third
Contact deviated buccally Short cusps

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CONTACT TAPERING SQUARE OVOID
Molars
(mesial
contact)
Buccal periphery almost at
bucco-axial angle of tooth
Same as premolars Same as premolars
Occlusal periphery at
junction of occlusal & middle
third of crown
Large cusps
Molars
(distal contact)
Buccal periphery at middle
third
More lingually deviated than
mesial
Buccal periphery in line with
central groove
Embrassures Wide variations
Incisal & labial are negligible
Incisal, lingual, occlusal & buccal
embrasures are NIL
Incisal, labial, buccal &
occlusal embrasures are wider
& deeper
Gingival & lingual
embrasures between
anterior teeth are the widest
& longest in the mouth
Gingival embrasures are almost
not noticeable
Gingival & lingual are short &
broad
- Buccal embrasures are
small, lingual are long

Contours
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• Convexities on the facial & lingual surfaces of tooth that affords
protection & stimulation of the supporting tissues during mastication.
Functions of contour:
1. Deflecting food
2. Maintenance of periodontal tissues
3. Maintain contact with adjacent tooth

Height of Contour
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• Area of greatest circumference on the facial and lingual surface of the
teeth.
• Protects the gingival tissue by preventing food impaction.
ANTERIOR POSTERIOR
Cervical 3rd on facial
& lingual surface
Gingival 3rd on facial
surface
Middle 3rd on lingual
surface

Types of contour
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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

Embrasures (spillways)
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• V-shaped spaces between the teeth that
originate at the proximal contact areas
between adjacent teeth.
• Curvature formed by two adjacent teeth in an
arch form a spillway space that is called an
embrasure.
• Serves 2 purposes:
• Provides a spillway for passage for food during mastication
• Prevents food from being forced into the contact area

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• Named for the direction towards which they radicate:
facial, lingual, incisal/occlusal, gingival
Lingual/Palatal
Facial/Buccal
Incisal/Occlusal
Gingival

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• Gingival embrasures filled with papilla – prevents food being trapped in
this region
• Anterior : papilla is triangular
• Posterior : tent shaped (col)
• Correct relationship of embrasures, cusps, sulci, marginal ridges & grooves
of adjacent and opposing tooth provide escape of food from the occlusal
surface during mastication

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• Embrassure is reduced: additional stress is created in teeth & supporting
structures.
• Embrassures is large: less protection to supporting structures
• Lingual embrasure is greater than buccal, since tongue can displace food
occlusally.

Marginal Ridges
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• Rounded borders of enamel that forms the mesial &
distal margins of occlusal surfaces of molars &
premolars and the mesial and distal margins of
lingual surfaces of incisors and canine.
• Always formed in 2 planes: buccolingually meeting
at a very obtuse angle
• This feature is essential when an opposing functional cusp occludes with
the marginal ridge.

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• Functions:
• Helps in prevention of food impaction proximally
• Mastication
• Protection of peridontium
• Marginal ridges of adjacent posterior teeth should be at the same height to
have a proper contact and embrasure forms.

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• Marginal ridges with normal occlusal

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• Marginal ridges with exaggerated occlusal embrasures causes drifting of
tooth which leads to wedging of food

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• Adjacent marginal ridges are not compatible in height - drives the debris
interproximally.

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• Marginal ridges with no triangular fossa, the vertical forces will impact
food interproximally.

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• Thin marginal ridges will be susceptible to fracture or deformation

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• Marginal ridges with no occlusal embrasures, the 2 adjacent marginal
ridges will act like a pair of tweezers grasping the food substance passing
over it.

Procedures of proper contacts & contours
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• Intraoral procedures:
• Tooth movement
• Matricing

Tooth movement
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• 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.

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Objectives:
• To bring drifted, tilted or rotated teeth to their indicated
physiological positions
• To close space between teeth not amenable to closure by
restoration
• To move teeth to another location
• To move 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.

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

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Tooth Movement
Rapid / Immediate Slow / Delayed

Rapid/ Immediate movement
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• 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
• To maintain the space gained by slow movement
• Separation shouldn’t exceed the thickness of the involved tooth’s
periodontal ligament thickness. ie: 0.2 – 0.5 mm

Methods
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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.

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Elliots separator
• Indicated for short duration separation that does not necessitate
stabilization
• Useful in examining proximal surfaces in final polishing of restored
contacts.

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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.

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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

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• Types:
• Wooden
• Plastic
• Elastic
• Transparent
• Medicated wedges
• Shape:
• Triangular
• Round
• Trapezoidal

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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 : ½” or 1.3cm so that it does not irritate the tongue or the
cheek.
• After placement the wedge should be firm and stable.

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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.

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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.

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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.

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• 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

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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

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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.

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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.

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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

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

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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.

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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

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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.

Slow/ Delayed tooth movement
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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
• Oversized temporaries
• Orthodontic appliances

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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.

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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

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

Matricing
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Procedure where a temporary wall is created opposite to the axial
walls, surrounding areas of tooth structure that were lost during
preparation.

Matricing
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The matrix should:
• Displace the gingiva and rubber dam away from the cavity margins
• Assure dryness and non-contamination of the cavity
• Provide shape for the restoration during setting of the restorative
material
• Maintain its shape during hardening of the material
• Confine the restorative material within the cavity

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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 inorder to confine the restorative
material excess.
Primary function of a matrix is to restore the anatomic contours and
contact areas.

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Parts of a Matrix system involves:
• Band
• Retainer
Matrix Band
• Supplied as strips of various dimensions
• Thickness of 0.001” or 0.002”
• Width may be ¼”, 3/8”, 5/16” or 1/8”
• Depending on the height of the proximal surface, suitable size is
selected.

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Retainer
• Device by which a band can be maintained in its designated position
and shape.
• Can be a mechanical device, dental floss, a metal ring or an impression
compound.

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Qualities of a good matrix includes:
1. Rigidity
2. Establishment of proper contour
3. Prevention of gingival excess
4. Convenient application
5. Ease of removal
6. Inexpensive

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Classification of matrices:
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)

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

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Universal Matrix (Tofflemire matrix)
• Designed by BR. Tofflemire
• Ideally indicated for 3 surface posterior tooth
• Commonly used for class II restorations
• 2 types:
• Straight
• Contra-angled

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Parts of a Retainer:

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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

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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.

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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
• Band is placed on a resilient paper
(contouring cannot occur on hard surfaces)

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• 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.

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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.

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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.

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5. Two ends of band are placed in the locking
vise, smaller nut is turned clockwise to
tighten the pointed spindle against the band.
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.

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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.

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Clinical Application:
• Damaging gingival attachment should be avoided
• One deeper proximal margin – band is modified (prevent damage to
gingiva or attachment on shallow side)
• Band may be trimmed for shallow gingival margin
• Positioned 1mm apical to gingival margin or deep enough to be engaged
by the wedge and 1-2mm above the adjacent marginal ridge.

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Ivory Matrix No.1
• Band encircles the posterior proximal surfaces so it is 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.

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

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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.

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2. Blacks matrix with gingival extension
• To cover 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

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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.

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• 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.

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Anatomical 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.

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• 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

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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

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• 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.

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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.

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T-shaped matrix
• Premade T-shaped brass/ stainless steel matrix
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.

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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

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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.

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• 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.

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• 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.

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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.

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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.

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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.

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• 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.
• Wedge is tightened
• Excess material is wiped off, held under the finger
pressure.

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• 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

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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.

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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

Contact Forming Instruments
100
• These are special instruments designed to create good contacts with
posterior composites.
• They push the matrix toward the contact area during light curing.
Eg:
• Contact Pro
• Optra contact

Contact Rings
101
• Work by providing slight separation of the contacting teeth.
• Spring action applies equal and opposite forces against the teeth thus
providing optimum separation.
• After separation, the composite is incrementally built and cured in a passive
manner.
• Finally, the ring is removed and
the teeth are brought back into contact.

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• According to their evolution, categorized as
• First generation systems
• Second-generation systems
First generation systems
• Introduced in the late 1990s
Include :-
• Palodent Bitine
• Contact matrix
• Composi-Tight
Palodent Bitine
Composi-Tight

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Palodent BiTine I and BiTine II
• First system that was available.
• Rings have rectangular tines which are
parallel.
• Provide optimum separation (0.55 kg/mm).
• Lack retentive design because of the parallel
tines but are easy to place on wide
preparations.
• BiTine II is an elongated ring to allow
stacking over the main ring in case of MOD
preparations.

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Contact matrix
• These rings have rectangular tines which are converging and hence
are more retentive.
• Provide optimum separation (0.38 kg/mm).
• A reverse ring is available for MOD preparations.

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Composi-Tight matrix
• Two separate rings are available for premolar and molar teeth.
• The rings have converging tines with retentive balls at the end for
firmer grip on the teeth.
• Omnidirectional.
Drawback:
• Contacts produced are not so tight (0.27 kg/mm).
• Large diameter of the rings can lead to their collapse if used in wide
cavities.

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Precontoured sectional matrix bands
• All these systems rely on precontoured sectional dead soft metal
matrices
• Available in various shapes, thicknesses and sizes.

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Benefits with the Sectional Matrices and Contact Rings
• Ease of use and good visibility.
• Anatomic contour of the bands ensures optimal contact areas and
embrasures.
• Less tension on the teeth and greater comfort for the patient
• No need for pre-wedging.
• Contact dimensions are adequate and in the correct anatomic location.
• Gingival adaptation of the restoration is good.

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Problems with early contact rings
• Ring collapse or 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.
• Most importantly, since the contact rings are made of stainless steel,
repeated usage and sterilization effects make them lose their
springiness over time.

109
Second - Generation Rings
Eg:-
• Composi-Tight 3D soft face ring system
• V3 ring system.

110
Composi-tight 3D Soft Face Ring System
The orange Soft Face 3D-Ring
• Used in most circumstances
• Ease of placement
• Ability to adapt to a wide variety of tooth
anatomies while reducing flash and restoring
proper contour.
The gray thin tine G-Ring
• Burnished tine ends
• Used where the shape of the dentition makes ring
retention more problematic

111
V3 Ring System
• Developed by Dr. Simon McDonald in 2008
• System has two types of rings for bicuspid and molar teeth
• Precontoured matrix bands
• Special wedge called the ''wave wedge'' to provide optimum gingival
adaptation of the matrix band.

112
It has two major innovations
• Fully made of Nickel-Titanium ;imparts more springiness and longevity
than stainless steel.
• V-shaped plastic tines to accommodate the wedge.
• The tines have extra width that enables the ring to contact more tooth
structure buccally and lingually.

Fender Wedges
113
• 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.

114
• Available in four color coded sizes
• Should be inserted with firm pressure providing a tight stable fit
throughout preparation.

Conclusion
115
• 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.

References
116
1. Operative Dentistry – MA Marzouk
2. Art & science of operative Dentistry – Sturdevants (5th edition)
3. Art & Science of Operative Dentistry – Sturdevants (South Asian Edition)
4. Textbook Of Operative Dentistry – Vimal K Sikri (1st Edition)
5. Dental Anatomy, Physiology & Occlusion – Wheeler’s (9th Edition)
6. Optimizing tooth form with direct posterior composite restorations
JCD Oct-Dec 2011 | Vol 14 | Issue 4

Contacts & Contours

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