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IDEAL CONTACT & CONTOUR
• Conserve the health of the periodontium.
• Prevents food impaction.
• Makes the area self cleansable.
• Improve the longevity of proximal restorations.
• Maintain the position of the tooth in the dental arch.
EMBRASURES
Embrasures are V-shaped spaces that originate at the
proximal contact areas between adjacent teeth and are
named for the direction toward which they radiate.
These embrasures are: (1) facial, (2) lingual,
(3) incisal or occlusal, and (4) gingival
FUNCTIONS
• Makes spillway for escape of food during mastication, thus decrease forces brought to bear upon the teeth during the reduction of
any material that offers resistance.
• Prevents food from being forced through contact area, thus keep food from being packed between the teeth.
• Reduce the forces of occlusal trauma brought to bear at the teeth thus dissipate and reduces occlusal forces.
• Permit slight amount of stimulation to the gingiva by frictional massage of food, thus protecting gingiva from undue trauma .
HAZARDS OF FAULTY EMBRASURES
• Decrease or absent : Additional stress created in the teeth and supporting structures during mastication
• Too large : Little protection to the supporting structures as food is forced into the interproximal surface by an opposing cusp .
CONTOURS
The facial and lingual surfaces possess
some degree of convexity that affords protection and
stimulation of the supporting tissues during mastication
Arrows show pathways of food passing over facial surface of mandibular
molar during mastication.
A, Overcontour deflects food from gingiva and results in understimulation of
supporting tissues.
B, Undercontour of tooth may result in irritation of soft tissues.
C, Correct contour permits adequate stimulation for supporting tissues, resulting in
healthy condition.
MARGINAL RIDGES • It should always be formed in two planes
buccolingually, meeting at very obtuse angle.
• Functions :
Balance of teeth in the arch .
Prevention of food impaction proximally.
Protection of periodontium .
Helps in efficient mastication .
Some marginal ridges function as working occluding cuspal
elements .
CLINICAL SEQUELAE OF FAULTY
CONTACTS & CONTOURS
•Food impaction / retention
•Gingival recession
•Gingival inflammation
•Fractured restoration
•Faculty occlusion
•Gingival irritation
•Periodontal complication - acute abscess or bone loss.
•Shifting of teeth (mesial drift).
Procedures for formulation of proper contacts and contours. Intra oral procedures Extra oral procedures Tooth movement matricing wax pattern
cast adjustment Rapid or immediate slow or delayed
Separating wires Wedge method Wood or plastic Ferrier double bow separator
Traction principle Over sized temporaries Elliot separator Orthodontic appliances
Tooth movement
• It is the act of either separating the involved teeth from each
other, bringing them closer to each other and / or changing their
spatial position in one or more dimensions.
• Objectives
Rapid or immediate tooth movement
Wedge method
Wood or plastic Elliot separator
Traction principle Non interfering true separator Ferrier double bow separator
• Matrix system - Matrix band, Retainer & Wedges.
• It is the procedure where by a temporary wall is created opposite to axial walls & surrounding areas of tooth structure that were lost during preparation.
Ideal requirements of a matrix band
Ease of application
Removability
Rigidity
Versatility
Height
Proximal contours
Positive proximal pressure
Should not react / adhere to the restorative material.
Functions Of Matrix Band Act as a temporary wall.
Re-establishment of contact.
Restrict extrusion of the restorative material and prevents overhangs.
Provide physiologic contour for proximal surface of restoration.
Assist in holding back gingiva & rubber dam during restoration.
Maintain the form of restoration during hardening.
CLASSIFICATION OF MATRIX SYSTEMS
Based on the material Based on the material
Non metallic matrix Metallic matrixNon metallic matrix Metallic matrix
Ex Mylar strip Ex Mylar strip
Haweno’s plastic Haweno’s plastic
Cervical matrixCervical matrix
cellulose acetatecellulose acetate
(cellophane)(cellophane)
cellulose nitratecellulose nitrate
(celluloid) (celluloid)
With retainerWith retainer
(mechanical) (mechanical)
Ex Ivory no 1& 8Ex Ivory no 1& 8
Tofflemire matrix band Tofflemire matrix band
With out retainerWith out retainer
(anatomical)(anatomical)
Auto matrix ,T-band,Auto matrix ,T-band,
S –band ,Soldered band,S –band ,Soldered band,
Compound supported Compound supported
matrix, Blacks matrix,matrix, Blacks matrix,
Copper band , AnatomicCopper band , Anatomic
matrixmatrix
• Based on anatomic contour
Anatomic matrix
Non anatomic matrix
• Based on material used
Metal
Copper
Brass
Celluloid
• Based on the support
Compound supported
Non compound supported
• Based on the dentition Deciduous Permanent
• Based on the retainer Automatrix Matrix with retainer
• Based on shape or design Straight Contra angled.
• Based on the position Circumferential Unilateral
Matrices for individual cavity preparation
Matrices for class -I cavity designs 4,5,6,7,& 8 preparation
- Double banded Tofflemire matrix
Matrices for class –II
1 Single banded Tofflemire [design 1,2,3,6,7,&8]
2 Ivory matrix No 1 [unilateral class -2]
3 Ivory matrix No 8 [Designs 1,2, & 3]
4 Black’s matrices [Designs 1,2 &3]
5 Soldered band (or) seam less copper band matrix
[Design 6,7,&8]
6 The anatomical matrix [Design 1,2,3,6,7 & 8]
7 Roll –in band matrix [Auto matrix]
8 S – shaped matrix band [Design 4,5,&7]
9 T-shaped matrix band
3) Matrices for amalgam restoration on the distal of the cuspid
a) S- shaped matrix
b) Tofflemire matrix
4) Matrices for class III –direct tooth colored restorations
a) For silicate cements – celluloid strips ,mylar strips .
b) For resins – cellophane strips , mylar strips
c) T – shaped matrix band
5) Matrices for class –IV direct tooth colored restorations
a) Plastic strip for inciso –proximal cavities
b) Aluminium foil incisal corner matrix
c) Transparent crown form matrices
d) Anatomic matrix
e) Modified S – shaped band
6) Matrices for class -V amalgam restorations
a) window matrix
b) S –shaped matrix
7) Matrices for class- V direct tooth colored restorations
a) Anatomic matrix for non – light cured materials.
b) Aluminum (or) copper collars for non – light cured materials .
c) Anatomic matrix for light & non- light cured materials
Materials used as matrices
• Stainless steel
• Platinum plate
• Brass
• Copper
• Tin
• Cellulose acetate (cellophane)
• Cellulose nitrate (celluloid)
• Polymer materials
Matrices are commonly supplied as
• Width - 1/4 ",3/8 ",5/16 " (or) 1/8".
• Thickness - 0.002 inch (0.05mm) &
0.0015 inch (0.038 mm)
Height should be :
occlusally – 1-2 mm above the marginal ridge
gingivally – 1mm below the gingival margin.
Tofflemire matrix/ universal matrix
Large Knurled nut
Small knurled nutHead
Locking vise
Slots Pointed Spindle
– Always be sure that the slotted end of the vise is facing gingivally.
– Ideally, the retainer should be parallel and adjacent to the facial surfaces of the quadrants of teeth being operated on.
Two techniques : - Single banded - Double banded
MATRIX BURNISHING
With band on pad ,use small burnisher to deform band
Use large burnisher to smooth band contour
The convex side of a spoon excavator is used to impart a convex contour to the matrix band
TOFFLEMIRE MATRIX SYSTEM REMOVAL
Removal of the handle stabilizing the band with the fingers while releasing the knob insures against fracture of the soft amalgam
Removal of band in angular direction
WEDGES
Natural eg: woodNatural eg: wood PreformedPreformed
Synthetic eg: plasticSynthetic eg: plastic Custom madeCustom made
MedicatedMedicated RoundRound
Non medicatedNon medicated TriangularTriangular
It is a wooden or plastic device placed interproximally which approximates the band on to the tooth and prevents gingival overhang of restoration.
Classification of wedgesClassification of wedges
BASED ON MATERIALBASED ON MATERIAL
PLASTIC WOODENPLASTIC WOODEN
BASED ON SHAPE BASED ON SHAPE
ROUND TRIANGULAR ROUND TRIANGULAR
BASED ON BASED ON MODIFICATIONMODIFICATION
Modified UnmodifiedModified Unmodified
METALMETAL
1 They assure close adaptability of matrix band to the tooth, gingival to the gingival margin of preparation. This will prevent gingival overhangs of the restorative material.
2. Protects the interdental col by preventing restoration impingement.
3. Defines the gingival, facial & lingual extent of the contact area.
4. Creates some separation to compensate for the thickness of matrix band .
FUNCTIONS OF WEDGES
5. Establishes a traumatic retraction of the rubber dam and the
gingiva, there by producing a temporary hemostasis and
minimizing moisture by adsorption
6. Assure immobilization of matrix band during restoration
placement.
7 The wedges can be impregnated with haemostatic solutions to
obtain hemostasis during restorations.
Advantages of wooden wedges• Easily cut & Trimmed .
• Absorb moisture intra orally to swell and expand slightly, thus improving proximal retention of band.
• Relatively flexible .
• Economical.
- Example : Orangewood, Hemowedges Maplewood, pine(soft) Oak (hard)
Plastic /Resin wedges- Opaque / Transparent
• Can be plastically molded and bent to correspond with the configuration of interdental col.
• Transparent plastic Wedges can transmit light through, suitable for light cured restorations.
• Relatively rigid hence tooth separation occurs easily
• example Luci wedges
Round wedge
• Preferred in conservative Preferred in conservative Class II preparations.Class II preparations.
Triangular wedgeTriangular wedge
• Preferred with class II Preferred with class II preparations preparations with deep gingival with deep gingival margins because of margins because of greatest width at its basegreatest width at its base
Criteria to be followed for
wedge selection
Not all cavities need to be wedged .
A gingival floor placed on a convex proximal surface example -lower 2nd bicuspid, does not need a
wedge.
Milder or flatter convexity - should be braced with a wedge
Flat and concave surface - require wedging
Wedges must not restrict the band from bulging outward to develop a good contact point.
• Wedge placed high - large gingival embrasure. Interfere with the development of a physiologic contact point.
• Wedges must be fitted and customized.
There is no universal wedge, and each one must be fitted for its individually intended space. Trimming can be accomplished by as scalpel, a gold knife or a diamond stone.
Rationale for tooth separation by wedge placement
• Based on tooth movement which utilizes the elasticity of the periodontal ligament when separated by an interdental wedge. This will also compensate for the width (Thickness) of the matrix band, so that after removal of the wedge and matrix, the separated teeth returns to its original position creating a perfect contact relation.
• Provides adaptation of matrix band in the cervical region.
• Protection from moisture and prevention of excess restorative material which could cause periodontal damage.
Types and techniques of wedge placement
• Single wedge
length -½ inch
• Double wedging techniques
* Double wedge technique
* Piggy back wedging technique
* Wedge wedging technique
Single wedge
• Depending on the location of contact, embrasure size and shape, a single wedge may be placed on lingual or buccal side
Double wedging
Indications:
- Wide faciolingual embrasures.
- When the proximal box is wide faciolingually .
Piggy-Back wedging
when wedge is significantly apical to the gingival margin, a
second wedge usually, smaller is piggy backed on the first.
Indication : when proximal box is shallow gingivally or inter Indication : when proximal box is shallow gingivally or inter proximal tissue level has receded or bothproximal tissue level has receded or both