Contact & contour

Building up tooth contact and contour

1. CONTACT AND CONTOUR

2. CONTACT POINT/AREA That part of the proximal surface of a tooth which touches the adjacent tooth mesially or distally . Synonyms: contact point , point of proximal contact .

3. Initially after eruption the tooth has a contact point with adjacent teeth. Physiological tooth movements result in the wear of the proximal surfaces causing the contact point to become contact area.

4. FUNCTION OF PROXIMAL CONTACT Prevents food from impinging in between teeth. Stabilizes all the teeth in the dental arch. Diverts food towards the buccal and lingual areas thus protecting the interdental papilla.

5. LOCATION OF CONTACT AREA MAXILLARY TEETH Incisal view shows the contact areas of all maxillary anterior teeth to be located at the center of the tooth crowns in a labio -lingual direction. The lingual embrasures widen out more than the labial embrasures.

6. A labial view shows the contact areas on the mesial surfaces of the central incisors to be in the incisal third of the crowns . In between the central & lateral incisors contact area is approximately at the junction of the middle and incisal thirds of the teeth .

7. The contact area on the distal surface of the laterals is in the middle third of the crowns . The mesial contacts on the cuspid teeth are nearly at the junction of their incisal and middle thirds. The contact areas on the distal of the cuspids is located in the middle third of the crowns.

8. T he contact areas on the mesial surfaces of the first bicuspids are centered at the junction of the occlusal and middle thirds of the crowns. The contact areas on the distals of the first bicuspids are located in the occlusal thirds of the crowns .

9. A buccal view shows the contact areas of upper first & second premolar & first molar to be located in the occlusal thirds of the crowns . An occlusal view indicates that the centers of the contact areas are located somewhat buccally to the midline of the bicuspid teeth and usually at about the midline of the first molar teeth.

10. A buccal view shows the centers of the contact areas to be located at about the junction of the occlusal and middle thirds of the first and second molar crowns. An occlusal view indicates that the contact areas are broader and are centered at about the midline of the teeth.

11. MANDIBULAR TEETH An incisal view shows the contact areas of all mandibular anterior teeth to be located at the center of the tooth crowns in a labio -lingual direction . A labial view indicates that the contact areas of the mandibular anterior teeth are uniform in nature and occur at the incisal third of the tooth crowns.

12. B uccal view shows the distal contact areas of the cuspids to be in the middle thirds of the crowns . An occlusal view shows the centers of the contact areas to be located at approximately the midline of the teeth.

13. A buccal view shows the contact areas between first& second premolar & first molar to be placed higher than on the mesials of the first bicuspids. They are located entirely in the occlusal thirds of the crowns . Occlusally the contact areas are progressively broader from the first bicuspids distally to the second molars.

14. The contact areas between the First, Second and Third Molar Teeth are located near the junction of the middle and occlusal thirds of the tooth crowns . Occlusally the contact areas are located near the midline of the crowns with only a slight tendency to be located toward the buccal .

15. CONTOUR Refers to the outline of a structure. The facial and the lingual surfaces of teeth possess some degree of convexity. Height of contour- a line encircling a tooth representing its greatest circumference

16. The height of contour is generally located at the cervical third of the facial surfaces of all teeth & the lingual surfaces of the incisors and canines. The lingual surfaces of the posterior teeth usually have their height of contours in the middle third of the crown.

17. FUNCTION OF NORMAL TOOTH CONTOUR Provide a degree of protection to the periodontium by preventing food impingement against soft tissues.

18. EMBRASURES These are V-shaped spaces that originate at the proximal contact areas between adjacent teeth. They are named according to the direction towards which they radiate. These embrasures are facial, lingual, incisal / occlusal & gingival.

19. MARGINAL RIDGE Ridge —Any linear elevation found on the surface of a tooth. Marginal  ridge — 1.They are elevations of enamel which form the mesial and distal margins of the occlusal surfaces of posterior teeth. 2.They also form the mesial and distal margins of the lingual surface of anterior teeth

20. FUNCTION OF MARGINAL RIDGE Marginal ridges are at uniform heights with adjacent marginal ridges. This relationship is necessary to provide the most efficient spillways for the deflection of food substances.

21. HAZARDS OF FAULTY REPRODUCTION OF CONTACT & CONTOUR

22. BROAD CONTACT 1.Changes the anatomy of the interdental col. 2.Produces a less cleansable interdental area. 3.May encroach on the embrasures. NARROW CONTACT 1. Causes food to be impacted vertically/ horizontally in the col area. 2.Predisposes to periodontal and caries problem.

23. OCCLUSALLY PLACED CONTACT GINGIVALLY PLACED CONTACT CONTACT AREA PLACED TOO GINGIVALLY 1.Impinges on the interdental papilla. 2.The contact size is decreased. CONTACT AREA PLACED TOO OCCLUSALLY 1. Shallow occlusal embrasure. 2. Flattened marginal ridge.

24. OPEN CONTACT 1.Allows for food impaction in the region of the interdental col.

25. IMPROPER CONTOUR UNDER CONTOUR: Causes food impingement of food into soft tissue. OVER CONTOUR : Deflects food away from gingiva resulting in understimulation of supporting tissues. PROPER CONTOUR UNDER CONTOUR OVER CONTOUR

26. IMPROPER MARGINAL RIDGE A MARGINAL RIDGE WITH NO OCCLUSAL EMBRASURE A MARGINAL RIDGE WITH EXAGGERATED OCCLUSAL EMBRASURE Causes driving of food debris interproximally . If debris are trapped in between it will be very difficult to remove.

27. MARGINAL RIDGES NOT COMPATIBLE IN HEIGHT Restoration with marginal ridge higher than adjacent tooth: Will cause the restored tooth to move. Dives food debris interproximally . Restoration with marginal ridge lower then adjacent tooth: Major movement of the unrestored tooth occurs.

28. OVERHANGING GINGIVAL MARGIN Predisposes to periodontal diseases.

29. DITCHING IN THE OCCLUSAL SURFACE A deficiency of amalgam along the margin, preventing the margin of the cavity preparation from being flush.

30. PROCEDURES FOR CREATING PROPER CONTACT & CONTOUR

31. INTRAORAL PROCEDURES 1. Tooth movement a)Rapid tooth movement b)Slow tooth movement 2. Matricing

32. Rapid tooth movement Should not exceed the thickness of the tooth’s PDL(0.2-0.5 mm). Types:- a)Wedge method:- 1.Elliot Separator 2.Plastic/Wooden wedges b)Traction method:- 1.Non-interfering true separator 2. Ferrier double-bow separator

33. ELLIOT SEPARATOR Used for short duration separation.

34. WOOD/PLASTIC WEDGES FUNCTION:- 1.Adapts the matrix band to the tooth gingivally . 2.Occupy the space filled by gingival interdental tissue thus preventing overfill. 3.Creates tooth separation compensating for the thickness if matris band 4.Protects interproximal tissue. 5.Immobilizes the matrix band.

35. Special types of Wedge placements DOUBLE WEDGING:- 1.Used when the proximal box is wide faciolingually . 2. two wedges are used, one from the lingual embrasure and one from the facial embrasure.

36. PIGGY BACK WEDGING:- This type of wedging is particularly useful for patients whose interproximal tissue level has receded. Second (usually smaller) wedge may be placed on top of the first to wedge adequately the matrix against the margin

37. WEDGE-WEDGING:- Used in case of a fluted root, such as the mesial surface of the maxillary first premolar. A gingival margin located in this area is concave. To wedge a matrix band tightly against such a margin, a second pointed wedge can be inserted between the first wedge and the band.

38. NON-INTERFERING TRUE SEPARATOR A single-bowed separator designed to give greater access to the surface being operated on; designed by Harry A. True. Indicated when continuous stabilized separation is required.

39. FERRIER SEPARATOR A set of balanced, double-bowed, adjustable separators designed by W.I. Ferrier.

40. Slow separation Used when rapid movement will endanger the condition of the PDL ( eg . in tilted/drifted tooth). METHODS:- a)Separating wires b)Oversized temporaries c)Orthodontic appliances

41. MATRIX SYSTEMS A matrix system provides and takes the place of the proximal tooth surface that was removed to restore the proximal contours and contact to their normal shape and function.

42. CLASSIFICATION OF MATRICES Depending upon method of retention:- a)Mechanically retained eg . Ivory matrix retainers, Tofflemire system. b)Self-retained eg . Copper/Stainless steel bands. On basis of transparency:- a)Transparent matrices eg . Cellophane/celluloid. b) Non-transparent matrices eg . Stainless steel

43. Requirements of a matrix band Rigidity- To withstand the condensation pressure. Versatility- To conform to any form. Comfortable to the patient. Height - A matrix band should extend 2mm above the marginal ridge height & 1mm below the gingival margin. Easy application & sterilization .

44. Dimensions of matrix bands Width-Ranging from 6.35mm to 9.525mm for permanent teeth. 3.175mm to 7.9375mm for deciduous teeth. Thickness-0.0381mm(0.0015in) to0.508mm(0.002 in) .

45. TOFFLEMIRE/UNIVERSAL MATRIX Designed by B.R. Tofflemire . Ideally indicated when three surfaces (i.e., mesial , occlusal , distal) of a posterior tooth have been prepared. It may be positioned on the facial or lingual aspect of the tooth.

46. WINDOW MATRIX Used for Class V amalgam restoration. Formed from Tofflemire matrix/Copper band. A window is cut in the matrix band slightly smaller than the original cavity dimension .

47. IVORY MATRIX NO.1 Indicated in unilateral Class II conditions.

48. IVORY MATRIX NO.8 Indicated in bilateral Class II/MOD situations.

49. Retainerless matrix systems Indicated in tilted or partially erupted teeth. Types:- 1.Retainerless automatrix band. 2.Anatomical matrix band 3.T shaped matrix band. 4.S-shaped matrix band 5.Full circle/Ring bands.

50. Automatrix System The automatrix system is an alternative to a universal retainer. There is no retainer used to hold the band in place. Bands are already formed into a circle and are available in assorted sizes in both metal and plastic.

51. Compound-supported matrix. The compound supported matrix is rarely used, but it is an alternative to the Universal matrix.

52. S-shaped matrix Ideally used for restoring distal part of canine & premolar. Normal stainless steel band is shaped by a mouth mirror handle.

53. Anatomic matrix & wedges 1. Most efficient means of reproducing contact & contour. 2. Contoured specifically for each individual case.

54. Sectional Matrices A thin polished PALODENT - type band and a tension ring produce a tight anatomic contact for class II restorations. Precontoured and ready for application to the tooth most suitable for mandibular first premolars and the distal surface of maxillary canines. BiTine ® rings Metal matrix forms

55. Matrices for Composite Restorations A plastic matrix, also referred to as a celluloid matrix or mylar strip , is used for class III and IV restorations.

56. Matrices for Composite Restorations CERVICAL MATRICES - The thin edges allow the excess composite to flow out and offer a closer rebuild of the natural tooth.

57. Transparent crown form matrices 1.These are stock plastic crowns which can be adapted to the tooth anatomy. 2.In bilateral class IV entire crown form is used. 3.In unilateral situations it is cut into half.

58. Matrix Systems for Primary Teeth The T-band is a T-shaped copper band. The top portion of the T allows the straight portion to adjust and fit the circumference of the primary molar.

59. A spot-welded band- Additional Matrix Systems for Primary Teeth