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MATRICES,RETAINER WEDGES

MATRICES,RETAINER WEDGES AND SEPARATORS . CONTENTS. WEDGES INTRODUCTION CLASSIFICATIONS FUNCTIONS WEDGE PLACEMENT TYPES OF WEDGING SEPARATORS USES PRINCIPAL METHODS - RAPID SEPARATORS - SLOW SEPARATORS.

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MATRICES,RETAINER WEDGES

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  1. MATRICES,RETAINER WEDGES AND SEPARATORS

  2. CONTENTS WEDGES • INTRODUCTION • CLASSIFICATIONS • FUNCTIONS • WEDGE PLACEMENT • TYPES OF WEDGING SEPARATORS • USES • PRINCIPAL METHODS - RAPID SEPARATORS - SLOW SEPARATORS

  3. MATRIX BAND AND RETAINER • INTRODUCTION • DEFINITION • SPECIFICATION • PURPOSE OF MATRIX • CLASSIFICATION • PROCEDURE • ADVANTAGES AND DISADVANTAGES

  4. MATRICES AND RETAINERS The word matrix derived from the latin mater, mother. “ That which contains and gives form to anything”. - The New Standard Dictionary of the English language Dental Matrix is a properly shaped piece of metal, or other material, used to support and give form to the restoration during its introduction and hardening. First introduced by Dr. Louis jack in 1871. Matricing :Is the procedure where by a temporary wall is created opposite to axial walls surrounding areas of tooth structure that were lost during preparation.

  5. SPECIFICATION OF MATRIX BANDS • Ease of application • Not be cumbersome • Easy to remove • Rigidity • Versatility (Easy adaptability and fixedness to the teeth) • Height • Proximal contour

  6. PURPOSE 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. • 6. Maintain the form of restoration during hardening

  7. CLASSIFICATION Based on the cavity preparations done 1. Matrices for class I cavity preparations - Double banded tofflemire retainer. 2. Matrices for class II cavity preparations - Single banded toffelmire. - Ivory matrix no.1 (unilateral class II) - Ivory matrix no.8 (Bilateral class II) - Black’s matrices - Seamless copper band or soldered band matrices - Anatomic matrix - Automatrix ( Roll – in band matrix ) - S – shaped matrix.

  8. 3. Matrices for a cavity preparation for amalgam restorations on the distal of cuspid. - S - shaped matrix - Toffelmire

  9. 4. Matrices for class III cavity preparations for direct tooth colored materials - Mylar strips or Plastic strips 5. Matrices for class IV cavity preparations for direct tooth colored materials - Plastic strip - Aluminium foil incisal corner matrix - Transparent crown form matrices - Anatomic matrix - Modified S - shaped matrix

  10. 6. Matrices for class V amalgam restorations - Window matrix - S-shaped matrix 7. Matrices for class V cavity preparations for direct tooth colored materials - Anatomic matrix for non – light cured, direct tooth colored materials - Aluminium or copper collars for non – light cured, direct tooth colored restorative materials - Anatomic matrix for light and non – light cured, direct tooth colored materials.

  11. Based on the materials used • Plastic • - Mylar strip • - Cellulose strip • - Hawe Neo’s plastic cervical matrix • 2. Metallic • a) With retainers • - Ivory no.1 • - Ivory no.8 • - Toffelmire matrix band • b) Without retainers • -Automatrix • - S band • - T band • - Black’s matrix • - Copper band • - Anatomic matrix

  12. UNIVERSAL OR TOFFELMIRE MATRIX RETAINER AND BANDS Straight and contrangled Convoluted and pre contoured bands

  13. Parts of TOFFELMIRE MATRIX RETAINER Small knurled nut Large knurled nut Locking vise Pointed spindle Head—open end and closed end

  14. Slot facing gingivally and retainer parallel to buccal surfaces of the teeth Incorrect

  15. Matrix band burnishing Beaver tail burnisher or Ball burnisher or Egg shaped burnisher

  16. Reflecting the handle to permit insertion of mesial wedge on retainer side. Trimming occlusal height of the matrix band with the help of crown sheers.

  17. Matrix band 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

  18. Ivory no 1 • For unilateral class II preparations • The band is attached to the retainer via a wedge shaped projection • which engages with the tooth at the embrasure of the unprepared surface

  19. Ivory no 8 • For bi-lateral class II ( MOD) preparations • - The band encircles the entire crown of the tooth

  20. BLACK’S MATRIX - For class II designs Left : For simple cases Right : with gingival extensions

  21. Auto matrix system • Automatrix is very useful for cusp restorations and class II designs. • They are available in narrow & wide regular, medium thin & med. Regular • Height - 3/16th to 5/16th inches (4.7 - 7.9 mm) • The tightening ratchet is released after it is in position. • Advantage : Auto loop can be positioned either on facial or lingual with equal ease • Disadvantage : Bands are not pre-contoured and development of physiologic proximal contour is difficult

  22. SEAMLESS COPPER BAND (With out seam or joints) Copper bands of assorted sizes make excellent matrices, but they are cylindrical and do not flare outward to engage distant contact points. They are susceptible to stretching and shaping with contouring pliers after the band has been rendered soft Bands are softened by heating to redness in a flame and quenching in water.

  23. Assorted copper bands, sizes 1 to 20. The size of a No. 1 band is 4 mm in diameter, and the size of a No. 20 band is 12 mm in diameter, with a wall thickness of 0.15 mm. Bands are softened by holding to redness in a flame and quenching in water.

  24. Pliers for shaping copper band. Left, Contouring pliers to bend the edges of the band Right, Stretching pliers. By pinching the metal the band becomes thinner and spreads apart. Stretching pliers in use to enlarge and contour the sides of the copper band. Reducing the thickness of the band at the region of the contact point with the help of green stone.

  25. Cutting the band off the tooth after the amalgam is sufficiently hardened

  26. ANATOMIC MATRIX This is the most efficient means of reproducing contact and contour. Entirely hand-made and contoured specifically for each individual case. Especially useful in mutilated teeth or teeth requiring unique anatomy to be reproduced in the restoration. A piece of 0.001-0.002" stainless steel matrix band is used. Usually it is supported by compound.

  27. S – SHAPED BAND • Class II designs • Class III on distal of the cuspid • with labial or lingual access • For large class V cavities extending • in to the proximal areas Contoured area for contact

  28. T – shaped band These are premade T-shaped brass or stainless steel matrix bands. The long arm of the T is bent or curled to encompass the tooth circumferentially and overlap the short horizontal arm of T. This section is then bent over the long arm , loosely holding in place. Wedges and stabilising compound can be applied as in the anatomic matrix to add further stability.

  29. Denovo matrix system

  30. Omni – Matrix System The Omni-Matrix is basically a preassembled Tofflemire retainer and band that is intended for one time use and then disposal.

  31. WINDOW MATRIX SYSTEM These are usually not indicated except for very wide cavities occluso - gingivally and/or mesio-distally, This matrix if formed using either a Tofflemire matrix or copper band matrix. The contrangle retainer is applied at the side of the tooth that does not have the preparation. A window is cut in the band slightly smaller than the outline of the cavity. Wedges are placed mesially and distally & restoration done. Similarly copper band can be used.

  32. Transparent crown form matrices These are "stock" plastic crowns which can be adapted to tooth anatomy. For class IV cavity preparations. In bilateral Class IV preparations use the entire crown form, but in a unilateral Class IV cut the plastic crowninciso - gingivally into two halves and use only the side corresponding to the location of the preparation. Thinned contact area Vent hole

  33. NEW TYPES • Circumferential mylar (contact molar band, ivoclar/vivadent). • Sectional mylar (cervical matrix, centrix, shelton, CT). • Triodent matrix and wedges • Sectional matrix (Palodent, composi-tight by garrison dental solutions, contact matrix rings danville engineering).

  34. SECTIONAL MATRIX SYSTEM • Principle : Wedge principle in matrices. • Procedure : • Placed in position by rubberdam clamp holder acting as a separator. • As the two ends rest on the teeth, the matrix band is forced against • the tooth surface. • The pressure on both sides at the same time gives slight separation, • thus aids in obtaining a tight contact.

  35. WEDGES Devices preferred for rapid separation. They are the third component of the matrix system.

  36. FUNCTIONS • They assure close adaptability of matrix band to the tooth, gingival to • the gingival margin of preparation. • 2. Protects the interdental col by preventing restoration impingement. • 3. Defines the gingival, facial & lingual extent of the contact area.

  37. . Creates some separation to compensate for the thickness of matrix band. . Establishes atraumatic retraction of the rubber dam and the gingiva, there by producing a temporary hemostasis and minimizing moisture by adsorption .Assure immobilization of matrix band during restoration placement.. Help in rapid separation

  38. CLASSIFICATION 1. Based on the shape : a) Anatomic – For deeply extended gingival margin because its greatest cross-sectional area is at its base. b) Non-anatomic – Preferred with conservative proximal boxes because its wedging action is more occlusal (near gingival margin) 2. Based on material used : a) Wooden wedges – They are easily cut and trimmed and they absorb water intra orally. This causes then to swell improving their inter proximal retention. eg. Rainbow wedges tm b) Resin wedges – They can be plastically molded and bent to correspond with the configuration of the inter dental col. eg. Fintrec transparent wedges.

  39. Depending upon the shape, they are classified as Triangular (anatomic) wedges () (Triangular in cross section). Round wedges (O) (Round in cross section)

  40. 3. Based on the manufacturing - custom made & - preformed 4. Based on the consistancy - Hard & rigid (oak wood) eg. Wizard wedge - soft and compressible (pine wood) eg. No-Hem

  41. Round toothpick versus triangular i.e., anatomic wedges. A, The triangular, wedge will not firmly support the matrix band against the gingival margin in conservative Class II preparations (arrow);. B, The round toothpick wedge is preferred because its wedging action is nearer the gingival margin. C, With deep gingival margins, the round toothpick wedge will crimp the matrix band contour if its diameter is above the gingival margin. D, The. triangular wedge is preferred with these preparations because its greatest width is at its base.

  42. Modified triangular i.e, anatomic wedge. A, Depending on proximal convexity, triangular wedge may distort matrix contour. B, A sharp bladed instrument may be used to modify the triangular steepness of the wedge, C, Modified and unmodified wedges compared, D, Properly modified triangular wedge prevents distortion of matrix contour.

  43. PROCEDURE Break off approximately ½ inch (1.2 cm) of a round toothpick. Grasp the broken end of the wedge with the No. 110 pliers. Insert the pointed tip from the lingual or facial embrasure (whichever is larger), slightly gingival to the gingival margin. Wedge the band tightly against the tooth and margin .If necessary, the gingival aspect of the wedge may be slightly wetted with lubricant to facilitate its placement.

  44. If the wedge is placed occlusal to the gingival margin, the band will be pressed into the preparation, creating an abnormal concavity in the proximal surface of the restoration . The wedge should not be so far apical to the gingival margin that the band will not be held tightly against the gingival margin. This improper wedge placement will result in gingival excess (i.e., overhang )

  45. Supporting matrix with blade of Hollenback carver during wedge insertion. Custom made tongue blade wedge may be used when excessive space exists between adjacent teeth

  46. TYPES OF WEDGING • 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 interproximal tissue level has receded or both.

  47. 2. Double wedging : Refers to inserting 2 wedges – one from the lingual and a second from the facial embrasures. The two wedges help to ensure that the gingival corners of a wide proximal box can be properly condensed as well as to minimize gingival excess. Indication : Faciolingually wide proximal boxes to provide maximal closure of band along gingival margin.

  48. 3. Wedge wedging : When concavity is present on the proximal surfacegingivally of the contact and extending as a fluting on to the root(mesial aspect of maxillary first premolars). Here the second wedge is inserted from lingual embrasure between the first wedge and the band.

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