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Contacts and contours

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contacts and contours in conservative dentistry

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Contacts and contours

  1. 1. 1 Department of Conservative Dentistry & Endodontic Under guidance of: Dr. SUMIT SHARMA Dr. RISHI MANAN Dr. NIKHIL PURI Dr. SAI GANAPATHY Dr. VINISHA PANDEY Dr. NEETU BANSAL Submitted by: Anil Kumar B.D.S. Final Year Batch: 2013-17 Contacts and Contours
  2. 2. CONTENTS… 2 1. Introduction 2. Contacts 3. Contours 4. Proximal ContactArea 5. Embrasures 6. MarginalRidges 7. Procedures for formulation of proper contacts andcontours: 8. Tooth movement 9. Matricing 10. Classification 11. Conclusion 12. References
  3. 3. • 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, embrasuresfor re-establishing the form and function of restored teeth. • Periodontal aspect & health of the tooth to be restored. 3 Introduction
  4. 4. 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 6
  5. 5. Food we consume moves in 3 different directions: 1. Occlusal surfaces 2. Contact & Gingival embrasures 3. Facial & Lingual sulcus 5
  6. 6. • Any decay occurring on the proximal surface is mainly due to faulty interrelationship between Contact Areas Marginal Ridges Embrasures Gingiva. 6
  7. 7. TIME OF ERUPTION: ONLY CONTACT POINT ARE PRESENT • Proximal Contact Point Proximal Contact Area 7
  8. 8. 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: 3 Types: 1. Tapering teeth 2. Square type 3. Ovoid type 8
  9. 9. CONTOURS 9 Convexities on the facial & Lingual surfaces of tooth that affords protection & stimulation of the supporting tissues during mastication. Functions of contour: 1. Deflecting food away from gingival margin 2. Maintenance of periodontal tissues 3. Maintain contact with adjacent tooth
  10. 10. HEIGHT OF CONTOUR 10 • 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
  11. 11. TYPES OF CONTOUR 11 OVERCONTOUR • Deflects food away from gingiva • Understimulation of supportingtissues • Plaque accumulation UNDERCONTOUR • Irritation to softtissues ADEQUATECONTOUR • Stimulation of supportingtissues • Healthy peridontium
  12. 12. EMBRASURES (SPILLWAYS) 12 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 passage for food during mastication  Prevents food from being forced into the contact area
  13. 13. 18 • Named for the direction towards which they radicate: facial, lingual, incisal/occlusal, gingival Facial/Buccal Incisal/Occlusal Lingual/Palatal Gingival 13
  14. 14. • Embrassure is reduced: Additional stress is created in teeth & supporting structures. • Embrassures is large: Less protection to supporting structures 29
  15. 15. MARGINAL RIDGES 15 • 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.
  16. 16. Functions: Helps in prevention of food impaction proximally Mastication Protection of peridontium 16 Marginal ridges of adjacent posterior teeth should be at the same height to have a proper contact and embrasure forms.
  17. 17. MARGINAL RIDGES WITH NORMAL OCCLUSAL 17
  18. 18. MARGINAL RIDGES WITH EXAGGERATED OCCLUSAL EMBRASURES CAUSES DRIFTING OF TOOTH WHICH LEADS TO WEDGING OF FOOD 18
  19. 19. ADJACENT MARGINAL RIDGES ARE NOT COMPATIBLE IN HEIGHT - DRIVES THE DEBRIS INTERPROXIMALLY 19
  20. 20. MARGINAL RIDGES WITH NO TRIANGULAR FOSSA, THE VERTICAL FORCES WILL IMPACT FOOD INTERPROXIMALLY 20
  21. 21. THIN MARGINAL RIDGES WILL BE SUSCEPTIBLE TO FRACTURE OR DEFORMATION 21
  22. 22. 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. 22
  23. 23. PROCEDURES OF PROPER CONTACTS & CONTOURS 23 Tooth movement Matricing
  24. 24. 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. 24
  25. 25. TOOTH MOVEMENT 25 Rapid / Immediate Slow / Delayed
  26. 26. RAPID/ IMMEDIATE MOVEMENT 26 • Mechanical type of separation • Creates either proximal separation at the point of separator’s introduction and/or improves closeness of proximal surface of opposite side. • Separation shouldn’t exceed the thickness of the involved tooth’s periodontal ligament thickness. ie: 0.2 – 0.5 mm
  27. 27. METHODS 27 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.
  28. 28. Elliots separator • Indicated for short duration separation • Useful in examining proximal surfaces in final polishing of restored contacts. 28
  29. 29. Wood/ Plastic Wedges • Used in both tooth separation for preparation and restoration • Triangular shaped wedges (wood/synthetic resin) • Base of triangle will be in contact with interdental papillae. • Apex must coincide with the gingival start of the contact area. 29
  30. 30. Types: Wooden Plastic Elastic Transparent Medicated wedges Shape: Triangular Round Trapezoidal 30
  31. 31. 41 Wedging techniques in the gingival 1. Single wedge technique • Single wedge is placed 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. 31
  32. 32. 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. 32
  33. 33. 4. Wedge wedging technique • Used in cases when there is a gingival concavity. • Inorder to wedge a matrix band tightly against such a margin, a second wedge is inserted between the first wedge and the band. 33
  34. 34. 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. 34
  35. 35. MATRICING 35 Procedure where a temporary wall is created opposite to the axial wall surrounding areas of tooth structure that were lostduring preparation
  36. 36. CLASSIFICATION OF MATRICES 36 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)
  37. 37. ii. Class II cavity 37 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 matrix band iv. Class IV cavity crown form a. Mylar strip b. Transparent matrix c. Modified S-shaped v. Class V a. Window matrix b. Cervical matrix
  38. 38. UNIVERSAL MATRIX (TOFFLEMIRE MATRIX) 38 • Designed by BR. Tofflemire • Ideally indicated when 3 surface of posterior tooth are prepared(i.e. mesial, occlusal, distal) • Commonly used for class II restorations • 2 types: • Straight • Contra-angled
  39. 39. 39
  40. 40. MATRIX BANDS 40 1. Uncontoured bands • Available in 2 thickness : 0.05 mm & 0.038 mm • Burnishing the thinner band 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.
  41. 41. 76 IVORY MATRIX NO.1 proximal surfaces so it is indicated in• Band encircles the posterior unilateral class II cavities. • Band is attached to the retainer via a wedge shaped projection. 41
  42. 42. IVORY MATRIX NO. 8 42 • 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.
  43. 43. BLACK’S MATRICES 43 1. For simple cases recommended for majority of small & medium size cavities 2. Blacks matrix with gingival extension(subgingival cavity)
  44. 44. COPPER BAND MATRIX / SOLDERED BAND 44 • 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.
  45. 45. ANATOMICAL MATRIX 45 • Most efficient means of reproducing contacts & contours • Hand-made and contoured especially for individual teeth.
  46. 46. ROLL IN BAND MATRIX ( AUTOMATRIX) 46 • 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
  47. 47. 8 S-SHAPED MATRIX BAND • For class III, class II and with facial/lingual extensions of class V • 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. 6 47
  48. 48. T-SHAPED MATRIX T-shaped brass/ stainless steel matrix• Premade bands • Longer arms of the matrix is bent to encompass the tooth circumferentially and to overlap the short horizontal arm of ‘T’ • Wedges can be used to stabilize the matrix. 48
  49. 49. Indications: • Class II cavities Advantages: • Simple • Inexpensive • Rapid • Easy to apply Disadvantages: • Not stable 49
  50. 50. TRANSPARENT CROWN FORM MATRIX 50 • Stock plastic crowns • Can be used for light cured resin material • For Class III and Class IV
  51. 51. • INDICATIONS: 51 • Large bilateral/unilateral class IV cavity • Oblique fractures of anterior teeth • Advantages: • Easy to use • Good contours can be established • Disadvantages: • Time consuming • Expensive
  52. 52. WINDOW MATRIX 52 • 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.
  53. 53. 53 RIGID MATERIAL SUPPORTED SECTIONAL MATRIX  An alternative to the universal matrix. CLINICAL PROTOCOL  The supporting material can be –light cured, thermoplastic and quick setting rigid PVS  Gingival wedge is placed to secure the band tightly to prevent any overhang  The matrix should be tight against the facial and lingual margins on the proximal surface.
  54. 54. 54  Shape of the stainless steel after trimming The strip is contoured  Burnishing the strip to produce occlusogingival contact and contour Contoured strip is positioned and wedged Rigid material supported sectional matrix completed Application
  55. 55. BARTON MATRIX 55  Matrix application for class I amalgam restoration The Tofflemire matrix retainer is used to secure a matrix band to the tooth. Because this type of matrix band does not adapt to the lingual or facial groove area of the tooth , an additional step may be necessary to provide a matrix that is rigid.  A piece of matrix material is cut to fit between the lingual surface of the tooth and the band already in place. A wedge is inserted between the Tofflemire and the cut piece of matric band.
  56. 56. 56 Application
  57. 57. 57 A quick setting polyvinyl siloxane (PVS) may be used between the sectional matrix and the Tofflemire matrix band, to prevent lingual displacement of the sectional matrix during condensation of amalgam   Alternatively , green stick compound is used. The end of wedge is covered with softened compound and inserted between the Tofflemire band and the cut piece of matrix material.
  58. 58. REFERENCES: 58 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 5. Dental Anatomy, Physiology & Occlusion – Wheeler’s (9th Edition)
  59. 59. CONCLUSION 59 • 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.
  60. 60. 57

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