Major Connectors

1. Major Connectors Presented by : Apurva Thampi 1

2. Contents Introduction Major connectors Role of major connectors Types of maxillary major connectors Review of indications Steps in Designing Types of Mandibular major connectors Review of indications Steps in Designing Recent advances Conclusion References 2

3. Introduction Name of components – descriptive of function Components Major connectors Minor connector Rests Direct retainer Indirect retainer Denture base 3

5. Major connectors A major connector joins the components of the removable partial denture from one side of the arch to the opposite side 5

7. Role of major connectors Be rigid Protect the associated soft tissue Provide means for obtaining indirect retention Provide a means of placement of denture base Promote patient comfort Self cleansing 7

8. Rigidity : Permits broad distribution of forces Protect soft tissue: Maxillary connector – 6mm from marginal gingiva Mandibular connector – 3mm from marginal gingiva 8

9. Provide means of indirect retention: By use of indirect retainers, rotation around the fulcrum line can be prevented Promote patient comfort: Edges should be contoured 9

10. Major connector is based on the principle of leverage 10 It will limit movement possibilities by acting as a counter-acting lever CROSS-ARCH STABILITY

11. Major connectors 11

12. Requirements of maxillary major connectors Borders – 6mm from gingival margins Anterior border should blend with the palatal anatomy Borders should cross the margins at right angles Palatal strap – 8mm wide Open central connectors – medial borders should be located at the junction of horizontal and vertical surfaces 12

13. Thickness of the plate should be uniform Borders should be gently curved Intaglio surface should not be highly polished 13

15. Types of Maxillary major connectors • Palatal bar • Palatal strap • Antero-posterior palatal bar • Horse-shoe shaped • Antero-posterior palatal strap • Complete palate 6 types of maxillary major connectors 15

16. Palatal bar 16

17. Narrow, half oval Thickest point at the centre Gentle curved and should not form an angle Indications  class III (short span) application 17

18. 18 *Palatal bar has few advantages and should be avoided *Bulky – causes discomfort to the patient *Narrow antero- posterior width Advantage/Disadvantage

19. Palatal strap 19

20. Most versatile Band of metal with a thin cross-sectional dimension A-P dimension should not be less than 8mm 20

21. Width should be increased with the length of the edentulous span Indication Kennedy’s class II 21

22. 22 *Increased resistance to bending and twisting forces *can be kept thin *little interference with normal tongue action *increased tissue coverage *Excessive palatal coverage * Anterior border should be positioned posterior to rugae * Prone to papillary hyperplasia Advantage/Disadvantage

23. Antero-posterior palatal bar 23

24. Palatal bar + palatal strap 2 bars joined by a flat longitudinal element 24

25. Advantage/Disadvantage *Rigid *Minimises soft tissue coverage *Provides exceptional resistance to deformation *Uncomfortable *Bulky *Derives little support from bony tissue *Contraindication – reduced periodontal support 25

26. Horse shoe connector 26

27. Consists of a thin band of metal Lingual surface of remaining teeth to palatal tissue – 6-8 mm Should be symmetrical – equal height on both sides 27

28. Advantage/Disadvantage *Strong connector *Derives some vertical support from tissues of hard palate *Designed to avoid bony prominences Tendency to deform Does not provide cross-arch stabilisation Should be considered only if more rigid connectors cannot be used 28

29. Horse shoe major connector has a tendency to Flex or deform. Hence it is not a good connector When cross arch stabilization in required. 29

30. Antero-posterior palatal strap 30

31. Maximum usage Each strap – 8mm width, thin cross- section Borders – 6mm from gingival margin Posterior strap should not contact soft palate 31

32. Advantage/Disadvantage *Derives good support from hard tissues *L-beam effect – increases resistance to flexure +Extensive length of borders may cause irritation to the tongue 32

33. Complete palate 33

34. Provides ultimate rigidity and support Maximum tissue coverage Must be kept 6mm away from gingival margins Mechanical seal – presence of bead line along posterior border 34

35. ADVANTAGES All posterior teeth to be replaced Remaining teeth are periodontally compromised Provides vertical support Permits force distribution to the teeth as well as the tissues Comfortable Coverage of multiple planes – L beam effect 35

36. DISADVANTAGES Adverse soft tissue reaction may occur – soft tissue hyperplasia – poor oral hygiene and prolonged periods of denture wearing 36

37. Indications Case Type of major connector Weak periodontal support Wide palatal strap or complete palate Adequate periodontal support Palatal strap or A-P palatal strap Long-span distal extension A-P palatal strap or complete palate Anterior teeth to be replaced A-P palatal strap, complete palate or horseshoe major connector Presence of torus A-P palatal strap, A-P palatal bar, horse shoe connector 37

38. Design of maxillary major connectors : Outline primary stress bearing areas Outline non bearing areas Outline of connector areas Selection of connector type Unification 38

39. Requirements of mandibular major connectors Rigid without being bulky Must not impinge on the movable floor of the mouth Relief required between the rigid metal connector and underlying tissues 39

41. Types of mandibular major connectors • Lingual bar • Lingual plate • Double lingual bar • Labial bar 4 types of mandibular major connectors 41

42. Lingual bar 42

43. Most frequently used Cross-section – half pear shaped Broadest portion near the floor of the mouth 8mm space between gingival margin and floor of the mouth Presence of mandibular tori – surgical removal 43

44. *Minimal contact with remaining teeth *Simple design *Decreased plaque accumulation *Increased soft tissue stimulation *If care is not taken, frame work may not be rigid *Too thin or too flexible – concentration of potentially destructive forces on individual teeth 44

45. Lingual plate 45

46. Half pear shaped – this solid piece of metal extending from superior border to lingual surfaces of teeth Lingual border as low as possible - avoid interferences with functional movements Plate must completely close the interproximal surfaces 46

47. Superior border is knife-edged to avoid “ledging” Open embrasures or widely spaced teeth – modification – “step back” Metal should cross gingival margins at right angles To ensure rigidity – inferior border should be made thicker “Ledging” occurs when metal margins are thick or linear and provides unnatural contours “Step back” modification requires the superior border of the plate to cover the cingulum of the individual tooth 47

48. *Exceptional rigidity – des not interfere with functional movements *Stabilize periodontally weak teeth *May provide additional indirect retention *If mandibular tori cannot be removed, adequate relief should be provided *Extensive coverage – decalcification of enamel *Irritation of tissues in patients with poor oral hygiene 48

49. Double lingual bar 49

50. Lingual bar + lingual plate Upper and lower borders are similar to lingual plate No continuous metal sheet Upper bar – half oval cross-section (2-3 mm height and 1mm thickness) Two bars should be connected by rigid minor connectors 50

51. Rests should be placed at each end of the bar – no further posterior than 1st premolar 51

52. *Effectively extends indirect retention in an anterior direction *Free flow of saliva – marginal gingiva stimulation Tendency to trap debris Uncomfortable – multiple borders and thickness 52

53. Labial bar 53

54. Runs across mucosa on facial surface Half pear shaped Longer than lingual bar Height and thickness must be greater Successful treatment very limited 54

55. SWING LOCK MODIFICATION Labial component does not serve as major connector Hinge at one end and locking device on the other Permits RPD to reach inaccessible undercuts 55

56. Considered when remaining major connectors cannot be used *Patient acceptance is poor-uncomfortable *Bulk distorts the lower lip *Labial vestibule not deep enough to accommodate a rigid connector without encroaching on the gingival margins 56

57. Indications Tooth supported RPD Lingual bar Insufficient room between floor of mouth and gingival margins Lingual plate Anterior teeth with reduced periodontal support Lingual plate Anterior teeth with reduced periodontal support and large interproximal spaces Double lingual bar Replacement of all mandibular posteriors Lingual plate 57

58. Design of mandibular major connectors I – outline basal seat area on the diagnostic cast II – outline inferior border of major connnector III – outline superior border of Major connector IV – unification 58

59. 59

60. Contents Introduction Major connectors Role of major connectors Types of maxillary major connectors Review of indications Steps in Designing Types of Mandibular major connectors Review of indications Steps in Designing Acrylic dentures Recent advances Conclusion References 60

61. Acrylic dentures Most commonly used Indicated when the life of the denture is expected to be less Or if relining may be necessary Weaker and less rigid than the metal alloys - more likely to flex or fracture during function. 61Connectors -J. C. Davenport, R.M.Basker, J. R. Heath, J. P. Ralph, PO. Glantz, and P. Hammond (BDJ)

62. INDICATIONS During the phase or rapid bone resorption after tooth loss When remaining teeth have poor prognosis, and an extraction and replacement is expected Interim denture In growing individuals 62Connectors -J. C. Davenport, R.M.Basker, J. R. Heath, J. P. Ralph, PO. Glantz, and P. Hammond (BDJ)

63. Design for the replacement of one or two anterior teeth in young people is the 'spoon' denture. It reduces gingival margin coverage to a minimum, but a potential hazard is the risk of inhalation or ingestion. A more stable and therefore more widely applicable design is the modified spoon denture. Here one has the choice of relying on frictional contact between the connector and the palatal surfaces of some of the posterior teeth, or of adding wrought wire clasps. 63Connectors -J. C. Davenport, R.M.Basker, J. R. Heath, J. P. Ralph, PO. Glantz, and P. Hammond (BDJ)

64. Another acceptable design is the 'Every' denture which can be used for restoring multiple bounded edentulous areas in the maxillary jaw. Acrylic RPDs in the mandible often lack tooth-support making tissue damage highly probable. Such RPDs should therefore be avoided whenever possible. 64Connectors -J. C. Davenport, R.M.Basker, J. R. Heath, J. P. Ralph, PO. Glantz, and P. Hammond (BDJ)

65. Contents Introduction Major connectors Role of major connectors Types of maxillary major connectors Review of indications Steps in Designing Types of Mandibular major connectors Review of indications Steps in Designing Acrylic dentures Recent advances Conclusion References 65

66. Recent advances Recent work has shown that CAD/CAM/RP technologies can be successfully applied to the fabrication of RPD alloy frameworks 66

67. 67

68. RPD framework using PEEK 68

69. To conclude…. 69

70. Bibliography  McCracken’s removable partial prosthodontics – 12th edition  Stewarts removable partial prosthodontics – 4th edition  Partial dentures – John osborne and George Lammie – 4th edition  Connectors -J. C. Davenport, R.M.Basker, J. R. Heath, J. P. Ralph, PO. Glantz, and P. Hammond (BDJ)  Use of CAD/CAM technology to fabricate a removable partial denture framework (R. J. Williams, BA, PhD,a Richard Bibb, BSc, PhD,b Dominic Eggbeer, BSc,c and John Collis, BDS) (JPD) 70

71. Thank you!! 71

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