Contacts & contours/ practice dentistry


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Contacts & contours/ practice dentistry

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education
  3. 3. Contents • Introduction. • Definitions. • Proximal contour, contact areas and related structures. • Hazards of faulty reproduction of teeth in restorations. • Procedure for formulation of proper contacts and contours : 1. Tooth movements 2. Matrices - Retainers - Wedges • Conclusion.
  4. 4. Introduction
  5. 5. Definitions  Contact area.  Contour.  Embrasures.  Marginal ridge.
  6. 6. I. Proximal contour, contact areas & related structures  According to their general shape, teeth can be divided into 3 types : – Tapering teeth. – Square teeth. – Ovoid teeth.
  7. 7. Tapering teeth: Incisors – (inciso-apically) starts near the incisal edges, slightly labial (labio-lingually). Canine – Very angular, mesial contact  close to incisal edges and distal contact center of the distal surface. Premolar – Also angular, crowns constricted cervically with long cusps. Cusps may form, from 1/3rd to 1/4th the height of the crown. – Crowns tapered lingually, contact areas occurs buccally  at the buccal axial angle (bucco-lingually). – At the junction of occlusal 3rd and middle
  8. 8. Molars – Mesial contacts (bucco-lingually)  mesio-buccal axial angle of the tooth, (occluso-gingivally)  at distance from 1/3rd to ½ from the occlusal surface to C.E.J. – Distal contact shift lingually to the middle third (bucco-lingually) and at middle third occluso-gingivally. Embrasures – Incisal and labial  negligible. – Gingival and lingual  largest – Buccal  very small – Occlusal  wide and deeper – Gingival & lingual  wide and broad Proximal contour Anteriors Posteriors
  9. 9. Square teeth – Bulky & angular, little cervical constriction & proximal surfaces devoid of curves. Incisors – In line with incisal edges (labio- lingually). – plane contact instead of a point contact. Canine – Close to incisal edges & in line with them labio-lingually. Premolars – Broader contacts, shorter cusps, occlusal extent  occlusal 1/3rd , buccal extent  buccal 1/3rd .
  10. 10. Molars – Mesial contacts  buccal axial angle extending lingually 1-4mm (bucco-lingually). – From a mere line contact to including half the height of the crown (occluso-gingivally). – Distal contact  If are in small areas : • Midline of the crown (bucco-lingually) • Occlusal third (occluso-gingivally) – If are in large areas: • Occupy from 1/3rd to 2/3rd bucco-lingually. • Lower border of the marginal ridge to CEJ (occluso-gingivally). Embrasure – Incisal, labial, occlusal  Nil. – Gingival embrasure  barely noticeable, or may extent 1/3rd the height of the crown. – Buccal embrasure  when present, very narrow & flat. – Lingual embrasure  Narrow or wide. Proximal contour
  11. 11. Ovoid teeth – Transitional type, surfaces primarily convex. Incisors – Mesial contacts  starts at about 1/4th height of crown from the incisal edges. – Distal contact  starts 1/3rd to ½ height of crown from incisal edges. – Slightly lingually to the incisal edges (labio-lingually) Canine – Same as square type of teeth. Premolars – Short cusps. – Convexity of marginal ridge carries the contacts almost to the middle third.
  12. 12. Molars – Because of prominence of MB cusp, with bucco-lingual convexity. – Mesial contacts – at junction of buccal and middle third of the crown. – Distal contact – in line with central groove on the occlusal surface of the crown. Embrasures – Labial, incisal & buccal embrasure  larger. – Gingival & lingual embrasure  shorter & broad. Proximal contours
  13. 13. Contact Tapering [wide crowns and narrow crevices] Square [Boxed] Ovoid [Transitional] Between incisors Contact starts at the incisal ridge incisally and a little towards the labial, labiolingually Starts at incisal ridge incisally and in line with it labiolingually 1. Slightly lingual to the incisal ridge labio-lingually 2. Mesial contact starts at ¼ of the crown inciso- gingivally 3. Distal contacts starts 1/3rd to ½ of the crown inciso- gingivally To summarize the anatomical features of contact areas
  14. 14. Canines • Mesial contact at the incisal ridge • Distal contact near the middle • Very angular • Close to incisal ridges incisally. • In line with them labio lingually • Same as square type Bicuspids • Buccal periphery almost at buccal axial angle (buccal third) of the tooth. • Occlusal periphery at the junction of occlusal and middle third of the tooth. • Contacts is deviated buccally. • Long Cusps, form ¼ - 1/3 of the crown • Buccal periphery more towards buccal axial angle (buccal third) • Occlusal periphery is at occlusal third. • Short cusps. • Convexity of MR carries occlusal periphery towards middle 3rd . • Buccal periphery at the junction of buccal and middle third
  15. 15. Molars mesial contact •Buccal periphery almost at the buccal axial angle of the tooth. •O-periphery, at junction of occlusal and middle third of the crown. •Large cusps • Same as premolar • Extension lingually stops in the middle third (1-4mm) • Same as bicuspids Molar distal contact • Buccal periphery at the middle third. • Occlusal periphery at the middle third. • Distal contact of first molar is variable due to position of distal cusps • More lingually deviated than the mesial but not to the extent of the tapering teeth. • Buccal periphery in line with the central groove in the occlusal surface.
  16. 16. Embrasures • Wide variations • Incisal and labial are negligible • Gingival and lingual embrasures between anterior teeth are the widest and longest in the mouth. • Buccal embrasures are small. • Lingual embrasures are long with medium width • Gingival embrasures between posterior teeth are broad and long • Incisal, lingual, occlusal and buccal embrasures are Nil. • Gingival embrasures are almost not noticeable; if found they are very narrow and flat. • Lingual embrasures are very narrow and long • Incisal, labial, buccal, and occlusal embrasures are wider and deeper than others. • Gingival and lingual are short and broad.
  17. 17. II. Marginal ridges  A marginal ridge with these specifications is essential for : – The balance of the teeth in the arch. – Prevention of food impaction proximally. – Protection of the periodontium. – Prevention of recurrent and contact decay. – For helping in efficient mastication. Forces acting on marginal ridge •“They are elevated rounded ridges located on the mesial and distal edges on the occlusal surface of the tooth”. •Occlusal cuspal anatomy. •Triangular fossa. •Two planes bucco-lingually.
  18. 18. III. Facial & lingual contours & related structures  Cervical ridge.  Curvatures on labial, buccal & lingual of all maxillary teeth & buccal of mandibular posterior  uniform.  Average curvature about 0.5mm or less.  Mandibular anteriors  <0.5mm.  Mandibular posterior (lingually) 1mm.
  19. 19. IV. Hazards of faulty reproduction of teeth in restorations A. Contact size. B. Contact configuration. C. Contour. D. Marginal ridge.
  20. 20. I Contact size : I. Creating a contact area i.e. too broad, bucco- lingually or occluso- gingivally. II. Creating a contact area i.e. too narrow, bucco- lingually or occluso- gingivally. III. Open (loose) contact.
  21. 21. IV. A contact area placed too occlusally. V. A contact area placed too buccally or lingually. VI. A contact area placed too gingivally.
  22. 22. B. Contact configuration 1. Creating a contact area i.e. flat (deficient convexity). 2. Creating a contact with excessive convexity. 3. A concave contact area in a restoration. C. Contour - 1. Facial and lingual convexities. 2. Facial and lingual concavities.
  23. 23. D. Marginal ridges The following examples will illustrate the consequences incurred by the creation of faulty marginal ridge. 1. Absence of a marginal ridge in the restoration. 2. Marginal ridge with an exaggerated occlusal embrasure.
  24. 24. 3. Adjacent marginal ridge not compatible in height. 4. Marginal ridge with no occlusal embrasure. 5. A marginal ridge with no triangular fossa.
  25. 25. Procedures for formulation of proper contacts and contours I. Tooth movements. II. Matricing  Tooth movement  History: – A.O. Jarvis (1874) – Dr. Safford, G. Perry and W.I. Ferrier.
  26. 26. OBJECTIVES: 1. To bring drifted, tilted and rotated teeth to their physiologically indicated positions to maintain natural contacts and contours. 2. To close the space between the teeth which is not closed by restorative methods.
  27. 27. 3. To move the teeth in order to improve the health of periodontium. 4. To move the teeth apically (intrusion) and occlusally ( extrusion) to make them restorable. 5. In order to expose the proximal surface to polish proximal restorations. 6. To change the position of teeth from non-functional or a traumatically functional position to a physiological functional position.
  28. 28. 7. To detect proximal caries which is not detected by conventional methods. 8. To create a space sufficiently for the thickness of the matrix band inter-proximally. 9. To remove foreign bodies collected between teeth which is not removed by floss, brush or explorer.
  29. 29. Two principle methods of tooth movements / separation: 1. Rapid or Immediate tooth movement / Separation. 2. Slow or Delayed tooth movement / Separation. I. Rapid or Immediate Separation / tooth movement: This is a mechanical type of separation that creates, either proximal separation at the point of the separators introduction and / or improved closeness of the proximal surface opposite the point of the separators introduction.
  30. 30. Advantages of Rapid Separation: • Procedure is quick and stable • Most valuable & frequently used • More advantageous than slow separation method Disadvantage: • Chances of rupturing Pdl fibers is more and also rapid separation may induces pain or soreness. Rapid separation is achieved by two principles: 1. Wedge principle 2. Traction principle
  31. 31. 1. Wedge principle: Separation is achieved by placing pointed wedge shaped device between the teeth and slowly inducing pressure in order to create space at the contact area. Ex: Elliot’s separator, Wedges.
  32. 32. 2. Traction principle: This is achieved by a mechanical device which engages proximal surface of teeth to be separated by means of holding arms and then separation is achieved between the clamped teeth. Ex: Non-interfering true separator, Ferrier double-bow separator.
  33. 33. II. Slow or Delayed Separation / tooth movement: In this method, teeth are slowly and gradually forced apart by inserting certain materials between them. Examples: Brass wire/ligature wire, heavy rubber dam material, rubber elastics, oversized temporaries, Orthodontic appliances. Advantages: 1. Less chances of tearing Pdl fibers and doesn't cause much pain. 2. No mechanical device required. 3. Separators can be left in place for weeks together. Disadvantages: 1. Procedure is time consuming & is not stable.
  34. 34. II. Matrices the word matrix is derived from a Latin word ‘Mater” which means mother. Definition: “A properly shaped piece of metal or non metal, that supports and gives form to the restoration during its insertion and hardening”.
  35. 35. Evolution of matrices  Early matrices : The early advocates of contoured fillings included by W.H.Atkinson, M.H.Webb & S.H.Guilford.  Original matrix was introduced by Dwinello (1855).  Dr. Louis Jack matrix introduced (1871).  Others included: Huey, Perry and Brunton matrices.  Materials included: steel, brass, copper, platinum plate or foil, phosphor bronze, German bronze, silver & tin…
  36. 36. Ideal Requirements: 1. Should replace the missing wall temporarily 2. Should be easily inserted and removed 3. Should be sufficiently rigid to retain contour given to it 4. Should not react or adhere to the restorative material 5. Should resist the condensation pressure. 6. Should be more comfortable for the patient 7. Should be small and handy so that access and visibility is not affected.
  37. 37. Objectives: 1. To act as a temporary wall of resistance during insertion and hardening of the material. 2. To displace or retract gingiva and rubber dam. 3. To achieve dryness and non-contamination of operating field. 4. To resist and compensate for dimensional changes that can occur during setting. 5. To maintain natural contact and contours 6. To promote health of inter dental gingiva by preventing overhanging
  38. 38. Classification of matrices: I. Based on mode of retention : 1.Mechanical retained matrices : 2. Self retained matrices : Ex: 1. Tofflemire, Ivory no.1and 8, Steele’s siqveland self adjusting matrix clamp. 2. Black’s matrix and copper band supported by impression compound.
  39. 39. II. Based on material used. • Metallic ex: stainless steel, copper and brass • Non-metallic ex: Celluloid and polyester available as strips, open faced crowns (semicircular shape), crown forms (surrounds full tooth)
  40. 40. III. Gillmore's classification: a) Custom made : Prepared by dentist or assistant suitable size matrix is cut and impression compound placed in the place of wedge. b) Mechanical : Tofflemire, Seqviland, Ivory no. 1 and 8 c) Miscellaneous : T-Band, soldered band, seamless copper band, orthodontic band, blacks matrix.
  41. 41. IV. Patented (Branded) and Non patented : 1. Branded: 2. Non-branded: Ex: 1) Ivory no. 1 and 8, Tofflemire retainer. 2) Soldered band, wedge matrix, black matrices.
  42. 42. Ivory No. 1 The band encircles one of posterior proximal surfaces, therefore indicated in unilateral Class II cavities. Band is attached to the retainer through wedge shaped projections which engage the tooth through the embrasures of unprepared surface. TYPES OF MATRICES
  43. 43. Ivory No. 8: Band encircles entire crown therefore indicated for bilateral class II cavities, Extended Class I and also for unilateral Class II in which adjacent tooth is missing.
  44. 44. Tofflemire: • Also called as Universal matrix. • Designed by B.R.Tofflemire. • Ideally indicated when 3 surfaces of posterior tooth have been prepared. • commonly used for two surfaces class II restorations. • Bands are available in 2 thickness: -0.05 mm -0.038 mm
  45. 45. Advantages: • Placement on tooth buccal and lingual surface but however lingual approach requires contra angle design. • Retainer can be easily separated from band without disturbing restoration. • Available in smaller sizes also so that it can be comfortably used in deciduous dentition.
  46. 46. Blacks Matrix: •Designed by Dr. G.V.Black. A metallic band is cut so that it will extend only slightly over buccal and lingual surfaces of the tooth beyond buccal and lingual extremities of cavity preparation. This band is tied to the tooth with either a floss or wire at the corners of gingival ends of band.
  47. 47. Auto matrix (Retainer less matrix) : •Designed by L.D.CAULK Company, •Also called Roll-in band matrix. -Band vary in height from 3/16 to 5/16 inches. -Supplied in two thickness 0.015 & 0.02 inches.  Designed for any tooth in the arch regardless of its dimension. Best used in large class II restorations. Extensive class II restorations, especially those replacing one or more cusps. Partially erupted teeth.
  48. 48. Advantages: - Convenient to place - Primarily useful in patients who can’t tolerate retainers. - Improved visibility due to absence of retainer - Facial and lingual placement - Reduced time for application - Number of teeth can be restored in one visit Disadvantages: - Expensive - Instability renders it less suitable. - Proper contours and contacts may be difficult to
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  54. 54. WEDGES Definition: “Material made up of either wood or synthetic material that is used along with matrices during insertion and hardening of plastic restorative material”. • They are the third component of the matrix system.
  55. 55.  It is pointed  Triangular / Trapezoidal in cross section  Base of cone is towards interdental papilla.
  56. 56. Classification: I Based on material used: •Natural : Wooden wedges ex: orange wood •Synthetic : Plastic wedges, light transmitting plastic wedges, resin wedges, metallic-silver wedges (messing 1900), II Based on availability: •Preformed •Custom made – prepared by dentist / assistant
  57. 57. III Based on surface treatment: • Medicated (coated with astringents) Ex: hemo wedges • Non-medicated Ex: orange wood. I
  58. 58. Wedges serves the following purposes: • They assure close adaptability of matrix band to the tooth. • They assure immobilization of the matrix band • They create some separation to compensate for the thickness of the matrix band. • To retract gingiva and rubber dam. • They arrest bleeding temporarily and moisture in an area which may receive moisture sensitive dental materials.
  59. 59. TECHNIQUES OF WEDGE PLACEMENT  Piggy back  Double wedging  Wedge-wedging  Tongue blade wedging
  60. 60. Conclusion “ we as a clinician or a restorative dentist should have an adequate knowledge of the anatomical & functional aspects of contacts & contours so as to reproduce them with ideal restorative material, which in turn will help to maintain the oral cavity in sound health”……….
  61. 61. Thank you For more details please visit