Contact and contours

All details about contact and contours of teeth

1. CONTACT AND CONTOURS Presented by : Nischala Chaulagain BDS final year Roll no 15 Presented to: Dr. Amit Singh Department of Conservative and Endodontic

2. CONTENTS: Fundamental Curvatures Proximal Contact Area Labial And Buccal Contours Benefits of an Ideal Contact and Contour Tooth Movement Wedges Matrix Recent Advances

3. Proximal contact areas Interproximal spaces (formed by proximal surface in contact) 3. Embrasures (spillways) 4. Labial and buccal contours at the cervical thirds (cervical ridges) and lingual contours at the middle thirds of crowns 5. Curvatures of the cervical lines on mesial and distal surfaces (cementoenamel junction [CEJ]) – Fundamental Curvatures

4. Proximal contact area The area of proximal height of contour of the mesial or distal surface of a tooth that touches its adjacent tooth in the same arch. Initially called proximal contact point .

5. According to their general shape : 1. Tapering type: Wide crowns & narrow cervical region 2. Square type: Bulky, angular with little rounded contour 3. Ovoid type: A transitional type between tapering & square types. Surfaces are convex but infrequently they may be concave

6. Labial And Buccal Contours CONTOUR : Refers to the outline of a structure. The facial and the lingual surfaces of teeth possess some degree of convexity. L abial contour is present at the cervical thirds (cervical ridges) and lingual contours at the middle thirds of crowns

7. Height of contour The area of greatest circumference on the facial and lingual surfaces of tooth is called height of contour. In posterior teeth, height of contour is located in the gingival third of facial surface and middle third of lingual surface.

8. It protects the gingival tissue by preventing food impaction.

9. 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 .

10. Benefits of an ideal contact and contour Conserves health of periodontium Prevents food impaction Makes the area self cleansable Improves the longevity of proximal restorations Maintains the normal mesiodistal relationship of teeth in the dental arch

11. Hazards Of Faulty Reproduction Of Contact & Contour 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 Causes food to be impacted vertically/ horizontally in the col area. 2. Predisposes to periodontal and caries problem.

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

13. IMPROPER CONTOUR • Under Contour : Causes impingement of food into soft tissue. • Over Contour : Deflects food away from gingiva resulting in understimulation of supporting tissues Adequate Contour : Stimulation of supporting tissues : Healthy peridontium

14. Procedures For Creating Proper Contact & Contour INTRAORAL PROCEDURES 1. Tooth movement: a)Rapid tooth movement b)Slow tooth movement 2. Matricing

15. a)Rapid tooth movement: • Mechanical type of separation • Creates either proximal separation at the point of separator’s introduction and/or improved closeness of proximal surface of opposite side. Indications: • As preparatory to slow movement • To maintain the space gained by slow movement

16. 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. Elliot's Separator Indicated for short duration separation that does not necessitate stabilization . Useful in examining proximal surfaces in final polishing of restored contacts

17. Wood/ Plastic Wedges : Used in both tooth separation for preparation and restoration Triangular shaped wedges (wood/synthetic resin) Cross-section base of triangle will be in contact with interdental papillae. Two sides of the triangle should coincide with the corresponding 2 sides of the gingival embrasure. Apex must coincide with the gingival start of the contact area.

18. Functions : Hold the matrix band in position Slight separation of the tooth Provides space for placing matrix band Prevent gingival overhang Stabilizes matrix and retainer Assure close adaptability of matrix band to the tooth Protect interproximal gingiva from unexpected trauma

19. Types: Wooden Plastic Elastic Transparent Medicated wedges Shape: Triangular Round Trapezoidal

20. Wedging Method Location : Gingival embrasure just beneath the contact area. Selection : Depending upon the clinical situation. Wooden wedges can be trimmed using a knife or scalpel blade to produce a custom fit. Placement : From the lingual embrasure which is normally larger in size. But if it interferes with the tongue it may be placed from the buccal side. Length : so that it does not irritate the tongue or the cheek. After placement the wedge should be firm and stable.

21. Wedging techniques

22. Single wedge technique: Single wedge is placed in the gingival embrasure. The pointed tip is inserted from the lingual embrasure, slightly gingival to the gingival margin.

23. 2. Piggyback 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

24. 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. • Should be used only if the middle 2/3rd of the proximal margins can be adequately wedged.

25. 4. Wedge wedging technique: Used in cases when there is a gingival concavity as in the case of a fluted root. In order to wedge a matrix band tightly against such a margin, a second wedge is inserted between the first wedge and the band.

26. Triangular wooden wedges are more recommended since: Easy to trim and adapt well to tooth surface When properly shaped, they remain stable during condensation Absorb moisture and swell to provide adequate stabilization Wooden wedges can be cut from toothpicks

27. 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. Tightness of the wedge is tested by pressing the tip of an explorer firmly several points along the middle 2/3rd of the gingival margin against the matrix band.

28. b) Slow/ Delayed Tooth Movement Indications: When teeth have drifted and/or tilted considerably, rapid movement of the teeth to proper position will endanger the periodontal ligaments. Therefore slow tooth movement over weeks will allow proper repositioning of teeth in physiological manner. Methods: • Separating wires, Elastics • Oversized temporaries • Orthodontic appliances

29. Matrix – Matrix is a device that is applied to a prepared tooth before the insertion of the restorative material to assist in the development of the appropriate axial tooth contours and in order to confine the restorative material excess. Primary function of a matrix is to restore the anatomic contours and contact areas. Parts of a Matrix system involves: • Band • Retainer

30. Qualities of a good matrix includes: 1. Rigidity 2. Establishment of proper contour 3. Prevention of gingival excess 4. Convenient application 5. Ease of removal 

31. Classification of Matrixes: 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 Class I cavity a. Double banded Tofflemire (barton’s matrix)   ii. Class II cavity a. Single banded Tofflemire b. Ivory matrix No. 1 c. Ivory matrix No. 8 d. Copper band matrix e. Automatrix f. Anatomic Matrix iii. Class III cavity a. Mylar strip b. S-shaped iv. Class IV cavity form a. Mylar strip b. Transparent crown matrix c. Modified S-shaped v. Class V a. Window matrix b. Cervical matrix

32. 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.

33. Advantages: • Can be placed facially/ lingually • Retainer and band are stable when in place • Retainer is separated easily from the band • Retainer helps to hold the cotton roll (for isolation) in place

34. Matrix Bands Uncontoured bands • Available in 2 thickness : 0.002” and 0.0015” • Burnishing the thinner band to contour 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.

35. 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. These 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

36. Advantages: • Convenience • Improved visibility because of absence of retainer • Ability to place the autolock loop on facial/lingual surface Disadvantages: • Band is flat, difficult to burnish • Sometimes unstable even with the use of wedges • Development of proximal contour is difficult.

37. S-shaped Matrix Band • For class III, class II and with facial/lingual extensions of class V • Matrix band of 0.001” – 0.002” is used • 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

38. • Compound material is used to hold the band in position in the facial and lingual aspect and also in the gingival aspect.