Major Connectors

1. Major Connectors

2. Functions of a Major Connector • Unification • Partial denture acts as one unit • Connects various parts

3. Functions of a Major Connector • Stress Distribution • Distributes functional loads to both teeth & mucosa

4. Functions of a Major Connector • Cross-Arch Stabilization (Counterleverage) • Bracing elements on one side of the arch providing stability to the other

5. Requirements of a Major Connector • Rigidity • Functions as one unit

6. To Increase Rigidity • Use a more rigid alloy • Chrome-cobalt > gold alloys; cast > wrought • Shape • 1/2 round > 1/2 pear shaped > flat bars

7. To Increase Rigidity • Increase the bulk as the length increases • Corrugate linguo-plate or rugae areas

8. Requirements • Non-Interference with Tissues • Should not enter undercut areas • avoid by changing path of insertion • or by using blockout

9. Non-Interference With Tissues • Avoid terminating on: • Free gingival margin • Cross abruptly at 90o • Relief is used to minimize impingement (Fig 2-17, Stewart's)

10. Non-Interference With Tissues • Avoid terminating on: • Hard structures such as the mid-palatal suture or mandibular tori • Place relief

11. Non-Interference With Tissues • Avoid terminating on: • Lingual frenum & the movable soft palate • Soft tissue movements must also be allowed • Careful intraoral exam

12. Minimize Food Impaction • Locate margins away from the FGM • Eliminate "traps" or large concavities where food can collect

13. Unobtrusive • Smooth transition from connector to denture base - butt joint

14. Unobtrusive • Line angles and edges should be smooth and rounded • Borders should not interfere with speech (Fig 2-21, Stewart's)

15. Mandibular Major Connectors • Lingual Bar • Lingual Plate • Continuous Bar

16. Mandibular Major Connectors • Lingual Bar • Most common in mandibe • Use whenever possible

17. Mandibular Major Connectors • Lingual Bar • Shape • Flat on tissue side • Convex or tear-drop on tongue side • (1/2 pear shape, with thin edge toward teeth) (Fig 2-35, Stewart's)

18. Mandibular Major Connectors • Lingual Bar • Size • Occluso-gingival width = 4 to 6 mm • Thickness = l.5 to 2 mm

19. Inferior Border Mandible • Patient lifts tongue • Activates floor of mouth • Measure from tip of probe to free gingival margin

20. Inferior Border Mandible • Record values in chart, transfer to cast

21. Lingual Bar • Position • Superior border • l.5-2.0 mm or more below FGM • As far from gingival margin as possible (Fig 2-15, Stewart's)

22. Potential Impingement • Anterior major connector moves toward tissue as the posterior portion is loaded • Space needed more when ridge is less vertical (Fig 2-33, Stewart's)

23. Mandibular Major Connector Relief • Eliminates impingement • Wax spacer (relief) placed under major connector • one thickness of 30 gauge wax

24. Lingual Plate (Linguoplate) • Lingual bar with extension over cingula of anterior teeth • Use where a lingual bar cannot be used

25. Lingual Plate Indications • Potential Impingement from lingual bar • High floor of the mouth • Prominent lingual frenum • Lingual tori

26. Lingual Plate • Rest at each end of lingual plate • Prevents forces being directed facially • Easier denture tooth addition than bar

27. Lingual Plate Variations • May show through embrasures (Fig 2-41 & 43, Stewart's)

28. Continuous Bar Retainer (Kennedy Bar, Double Lingual Bar) • Lingual bar with secondary bar above cingula • Secondary bar acts as indirect retainer

29. Continuous Bar Retainer • Potential food trap between two bars • Normally avoid

30. Maxillary Major Connectors • Anterior-Posterior Palatal Strap • Full Palatal Strap • Palatal Strap • Anterior Palatal Strap

31. Maxillary Major Connectors • Terminate 4.0 mm or more from free gingival margin when possible

32. Anterior-Posterior Palatal Strap • Maximum rigidity • Minimum bulk • Use in most cases • Especially torus palatinus

33. Anterior-Posterior Palatal Bar • A narrow (A-P) variation of anterior-posterior palatal strap • Double palatal bar connector • Requires greater bulk for rigidity

34. Anterior-Posterior Palatal Bar • More objectionable to the patient • Strap connectors provide greater distribution of stresses

35. Full Palatal Plate • Maximum tissue support • Connector of choice in long distal extension cases • Six or less anterior teeth remain

36. Full Palatal Plate • Abutments are periodontally involved • Maximum stress distribution • Flabby tissue • Shallow palatal vault

37. Full Palatal Plate • Greater stability and stress distribution • Not used with torus • Increases retention

38. Full Palatal Plate • Connector should: • Be fabricated of uniformly thin metal • Have accurate anatomic reproduction of the ruggae • improves strength and rigidity

39. Full Palatal Plate • Connector should: • Cover same area as complete denture posteriorly • Have large surface area of mucosal contact • improves potential for retention

40. Full Palatal Plate • Generally of cast metal • Acrylic resin used in interim prostheses

41. Palatal Strap • Usually use for Class III & IV cases • Wide anterio-posteriorly

42. Palatal Bar • Don’t use • Narrow anterio-posteriorly • Thick occluso-gingivally • Palatal bar objectionable due to bulk (Fig 2-24, Stewart's)

43. Palatal Strap (or Bar) • Never use in cases involving distal extensions or replacement of anterior teeth since it must be made bulky for rigidity • Relief may be required over bony midline • Not used with torus

44. Anterior Palatal Plate (U-Shaped or "Horse-Shoe" Palatal Connector) • Poor connector • Never use unless absolutely necessary • Requires bulk in the rugae area (where the tongue requires freedom) for rigidity

45. Anterior Palatal Plate • Too flexible • Allows movement at the posterior • Traumatic to the residual ridge • Use only where torus prohibits other connectors

46. Flexes, impinging on soft tissue

47. Unilateral RPD • Dangerous • Avoid • aspiration