contactsandcontours

1. CONTACTSAND
CONTOURS
DR ASHWINI M PATIL
Reader
Navodaya dental college
Raichur

2. INTRODUCTION
A healthy dentition comprises of fully erupted teeth with
proper occlusal and proximal contacts that help to stabilize
and maintain the integrity of the arch . All the teeth have
tendency toward mesial drift ,which is primarily resisted by
contact point of adjacent teeth. Decay in the proximal
surface occurs mainly due to faulty inter-relationship between
contact area ,marginal ridges, embrasures, and gingiva. A
clinicians role is to re-establish the original or correct the
faulty contact to form physiologically stable contact &
inabilty to restore this relationship disrupts harmony and
can result in deleterious consequences like food impaction
,caries,drifting ,tilting or rotation of teeth.

3. CONTOURS
All teeth have some specific convexity on the
facial ,lingual , proximal and occlusal surface of
teeth that afford the protection and stimulation
of the supporting tissues during mastication. This
convexity are called contours.
TYPES
 Faciolingual contour
 Proximal contour
 Occlusal contour

4. Contours on the facial and lingual
surface
• Facial surface - cervical one
third of all teeth
• Lingual surface - cervical
one third of incisor and
canines
-Middle one third of the
premolar and molar

5. Problems of over or under contouring of
the facial and lingual surface
Over contoured restoration
They deflect food from the
gingiva causing poor gingival
stimulation. The gingiva
become flabby ,red and
chronically inflamed due to
increased plaque retention
Under contoured restoration
This result in irritation and
trauma to the attachment
apparatus.

6. Contours on the proximal
surface
Teeth show convexities on
the distal and mesial
surface. The area with
maximum convexity on
the proximal surface is
called the proximal height
of contour. Proximal
height of contour
responsible for the
creation of the
a)Proximal contact
b)Embrasure space

7. Proximal contact
• Proximal convexity of the teeth create area of contact
between adjacent teeth with in the same arch. These
are called proximal contact area. Initially as teeth erupt
the teeth contact each other at a point(point contact).
With the passage of time, physiologic tooth movement
causes frictional wear enlarging the contact point to
contact area.

8. Importance of contact
 Preserves the stability and
integrity of the arch by
maintaining normal mesio
distal relation ship of teeth.
 Prevent food impaction
interdentally
 Protect the soft tissue from
periodontal disease
 conserve the teeth from
proximal caries
 Premature restorative
failure does not occur if
stable proximal contact is
present.

9. Size of contact
• Anteriorly- contact point
• Posteriorly –contact area
about 1.5-2mm
• LOCATION OF CONTACT
Anterior teeth – incisal
one third
Posteriorly - junction
of incisal and middle one
third

10. Embrasures
• Embrasures are v shaped
spaces present
interproximally around
the proximal contact
existing between the
adjacent teeth.
Types
1.Buccal embrasure
2.Lingual embrasure
3.Incisal/occlusal
embrasure
4.Gingival embrasure

12. Functions of Embrasures
1)Serve as spillways for the escape of food
during mastication
2)Prevent trapping of food in to the contact
area
3)Protect the underlying supporting tissue
during mastication

13. Improper contact size
Too broad contact
• It will change the tooth anatomy
• It will change the interdental ‘col’ by
broadening it. The delicate non keratinized
epithelium may get damaged increasing
the chance of periodontal tissue.
• With too broad contact the interdental
area is difficult to clean increase the risk
of future decay.
Problems associated with faulty
reproduction of contacts in restoration

14. Too Narrow contact
• It will change the tooth
anatomy
• The embrasure size will
increase leading to
impaction of food
vertically and
horizontally, thereby
damaging periodontal
tissue.

15. Improper contact location
If Contact are placed :
• Too occlusally -It will cause flattening of marginal -
ridges, resulting in too shallow
occlusal embrasure
• Too buccally/lingually- will encroach upon the
respective embrasure
• Too gingivally - will reduce the size of gingival embrasure
and encroach upon interdental gingiva

16. Open contact
Open contacts would create the problem ready
inflow of food causing accumulation of debris ,
plaque and damage to the periodontal disease

17. Procedures for developing
correct contact and contour
• To create proper contact and contour with any
restorative material, the teeth have to be first
separated and then a temporary wall created
to support the restorative material in plastic
stage.
• Tooth separation to create space between
adjoining teeth.
• Matrix application on the prepared proximal
side.

18. RAPID SEPARATION
This is immediate type of separation . This
type of tooth movement involves separation
of teeth proximally at the point of insertion of
separator. The amount of separation produced
should not exceed 0.2-0.5mm. Rapid
separation can be done by two method
a) Wedge method
b) Traction method

19. Wedge method of separation
In this method space is
created by inserting
wedge shaped device
between the teeth.
There are two types of
separator
1)Wooden / Plastic
wedges
2)Elliot separator

20. Classification of Wedges
1)On the basis of method
of fabrication
a) Custom made wedges
b) Pre fabricated wedges
2)On the basis of
material used for
fabrication
a) Wooden wedges
b)Plastic or synthetic
resin wedges

21. Custom made wedges
• These are made by trimming wood or plastic
material in triangular shape to mach that of
embrasure. Trimming can be done by scalpel ,
gold knife or diamond stone.

22. Wooden wedges
These wedges are made from wood. It may be
soft and resilient or hard .they are easy to trim
and shape. They absorb water interiorly and
swell up ,which causes them to press more
press against the matrix there by improving
their retention. They are available in two
shape.
Triangular shape
Round shape

23. Triangular Shape Wedges
• These are most commonly used.
• Indicated in cavities with deep gingival margin
• The apex lies below the contact area
• The side of the triangle should be match with mesial
and distal embrasure
• Used to depress the rubber dam
• They are preferred in ideal class II cavities preparation
as wedging action close to the gingival margin
Round shape wedges

24. Prefabricated wedges
• They are in triangular in shape and supplied
in different size. Their shape should modified
by trimming to exactly meet that of the
gingival embrasure.

25. Light transmitting wedges
• These are transparent plastic wedges ,which are available in
with built in light reflecting property.
• Indication
Class II composite restoration : These light transmitting
wedges help to assist in directing light into inter proximal
areas during initial stages of class II composite curing .

26. Synthetic Resin/ Plastic Wedges
• They are commonly available different color
and size . They have to be trimmed or
plastically molded and bent according to the
shape of the inter dental col.

27. Technique of wedge insertion
• Select appropriate wedge, modify its shape according
to the shape of the embrasure
• Length of the wedge should half of an inch.
• Grasp the wedges with help of pliers and insert pointed
tip from facial or lingual embrasure whichever is larger.
• Wedge should come to lie slightly gingival to the
gingival margin of the proximal cavity, pressing the
band tightly against the tooth. Once placed it should be
firm and stable.
• Test tightness of the wedge with an explorer. the
explorer is pressed against the matrix to the margin.

28. Piggy- Back Wedging
• Useful in cases with
gingival recession of inter-
proximal tissue . In such
cases when the wedge
lies in the apical margin of
proximal cavity another
wedge smaller in size is
piggy backed on the first
one to fill the space and
press the matrix band
against the margin.

29. Double wedging
• This method used in
case of wide
faciolingual proximal
box. In such cases two
wedges are inserted,
one from facial and
other from lingual
embrasure.

30. Wedge Wedging
• Used in maxillary surface
of first premolar where a
concavity may be present
on the proximal surface of
the contact and
extending to the root as
groove . In such case to
wedge a matrix band tight
against the tooth, a
second wedge may
inserted between first
and band.

31. Functions of wedges
• They create space between teeth to compensate the
thickness of matrix band.
• Immobilize the matrix band.
• Closely press the matrix band against the tooth in the
gingival area of the preparation preventing any
restorative material escaping below the band.
• Maintaining the health of interdental gingiva by
preventing material from impinging.
• Protect the gingiva from unexpected truma.

32. Elliot separator
• It is also called crab
claw separator. It is
mainly used for short
duration separation
such as
1)Examination of
proximal surface
2)Final polishing of
already restored
proximal surface.

33. Traction Method
• It is a method of rapid separation in which the teeth are
mechanically moved apart. The mechanical devices which are
used for the purpose are engaged on the proximal surfaces of
teeth by means of holding arm and the teeth are clamped.
Teeth are physically separated as the nut is turned by the
wrench .
Example: Ferrier double bow separator.

34. Matricing
• Is a procedure by which a temporary wall is
created opposite to axial wall that surrounds
the area of the tooth structure, which was lost
during tooth preparation.

35. Matrix
• Is a device which used to confine and give
shape to the restorative material during its
introduction and hardening. the matrix
assembly consist of two parts.
Matrix band
Matrix retainer

36. Matrix band
• It is a false wall in the form of thin piece of metal or
other material ,replacing the missing wall in cavity
preparation. it may be of different material such as
stainless steel ,(toffelemire,ivory bands
),copper(copper bands),celluloid(transparent strips).
• The height of the band should be such that it extend
2mm above the marginal ridge and 1mm below
gingival margin of the preparation.
• Matrix retainer : it is an instrument used to hold
matrix band in position.

37. Ideal requirements of Matrix
• It should be simple in design.
• It should be easily applied and readily removed
• It should be rigid enough to withstand condensation
pressure preventing the restorative material bulging
out.
• It should be able to adapt with the shape and position
of different types of tooth. It should be non reactive to
the tissue and restorative material.
• It should be inexpensive and readily available.
• It should be easy to sterilize.

38. Functions of Matrix
• It act as a temporary supporting wall
• It confines the restorative material and allow
it to acquire proper shape and form as it
harden.
• It retracts the gingiva and rubber dam as the
restorative material packed in the cavity.
• It helps to establish the proper contact and
contours.

39. Classification of Matrix Band
A)Depending upon the composition of band
material .
i) Stainless steal e.g:Toffelemire.ivory no.1
and no.8
ii) Copper: eg : Copper band
iii)Cellulose acetate : eg:cellophane
transparent strips.

40. B) Depending upon the method of retention
• i) Using retainers: Toffelemeire ,Ivory no.1and8
bands
• ii) Retainer less band: Copper band ,automatrix
C) Depending upon the preparation
• i) Mechanical matrix e.g:toffelemire retainer ,ivory
no.1and8
• ii) Custom made /anatomic matrix e.g compound
sectional metal strips.

41. Toffelemire retainer
• It is a versatile type of
matrix retainer. It is also
referred to as universal
matrix .it was designed by
BR Toffelemire .
• Advantages
Its main advantage is that
it can be placed on the
buccal or lingual side of
tooth as per requirement
It is very stable when in
position.

42. Indication
• It is ideally indicated for MOD cavities
• Class II cavities
• Class I cavities with buccal and lingual
extensions

43. Parts of Toffelemire retainer
• HEAD- This part accommodate
the matrix band. It is U shaped
with two slots. The open side of
the band should be held facing
upward when the band is
inserted and while positioning
the band around the tooth the
slot in the head should be
directed gingivally. The head
maybe straight or angulated
with respected to rest of retainer.
Accordingly there are two types
Straight toffelemire retainer
Contra angled toffelemire
retainer

44. Locking vice
• This has a diagonal slot. The locking vice is
positioned near the head, for the placing the
band in the retainer and positioning it around
the tooth.
• Pointed spindle
This is used to adjust the distance between
the head and locking vice and also adjust the
size of matrix band.

45. Small knurled nut
• Turning this nut clockwise tightens the pointed
spindle against the band and thus secure the
band in the retainer. The reverse motion release
the pointed spindle from locking vise thus
releasing the band from the retainer.
Large knurled nut.
• This is used to adjust the size of the loop of the
matrix band either to adapt or to loosen from the
tooth.

47. Ivory no.1 matrix
• The matrix consist of a
stainless steel band which
encircles the proximal surface
of posterior tooth. This is
attached to the retainer via a
wedge shaped projection. An
adjusting screw at the end of
the retainer adapts the band
to the proximal contours of
the prepared tooth.
• Indication
For restoring U/L ClassII cavity
when the contact on the
unprepared side is very tight

48. Ivory No .8
• This matrix consist of a
band that encircle the
entire crown of the tooth .
The circumference of the
band can be adjusted by
the adjusting screw present
in the retainer.
• Indications
For restoring Class II
cavities on one or both
proximal surface of
posterior teeth.

49. Copper band matrix
• They are cylindrical in shape and
can be selected according to the
diameter of the tooth to be
restored. the band are softened
by heating in flame and
quenching in water.
• For badly broken down teeth
especially those receiving pin
amalgam restoration.
• For complex situation like ClassII
cavities with large buccal or
lingual extension.
• Advantages
• Provide excellent contour
• Disadvantages
• Time consuming

50. Pre-contoured metal matrix strips
with metal rings
This consist of small
precontoured soft metal
matrices ready for application
of the tooth. They are selected
according to the tooth to be
restored &wedged to adapt to
the gingival contour. This
metal band held in place by
metal ring called BiTine Ring
INDICATION
 for small class 11 cavities
involving proximal surfaces in
posterior tooth.
 >for both amalgam &
composite restoration.

51. • Advantages
>ease of application.
>metal ring also afford slight tooth sepration.
>provide better proximal contour for posterior
composite restoration than traditional matrices.
Disadvantage
>expensive
>matrix band become bended easily especially if
the contact area of the adjuscent tooth is too
close preventing easy insertion of the band.

52. T –BAND MATRIX
• This is a preformed
stainless steel matrix
band without retainer
INDICATION
For class 1 cavities involving
one or both proximal
surface of posteriors
ADVANTAGES
>simple & inexpensive
matrix band system
>rapid & easy to apply

53. AUTOMATRIX
Is a retainer less matrix system designed for any tooth regardless of its
circumference and height .
Components
1 Auto matrix band:
available in three widths
> 3/16th inch
>1/4th inch
>5/16th inch
2 Automate 11 tightening device
- Adjust loop of band according to circumference of the tooth to be
restored.
3 Shielded nippers
- Used to cut auto lock loop ,so that band can be separated & remove from
the tooth.

54. Indication
>Complex amalgam restoration especially when one or
more cusp are to be replaced.
Advantages
> Convenient to be use .
>Improved visibility due to lack of interference from a
retainer.
> Rapid application.
Disadvantage
> Band are flat ,so difficult to burnish
> Cannot develop proper proximal contact & contour.
> Expensive