1. Major Connectors
Rola M. Shadid, BDS, MSc

2. Major Connector
A major connector is the component of the RPD that connects the parts of the prosthesis located on one side of the arch with those on the opposite side.
It is that unit of the RPD to which all other parts are directly or indirectly attached.

3. Functions of Major Connector
Unification
Partial denture acts as one unit
Connects various parts

4. Functions of Major Connector
Stress Distribution
Distributes functional loads to both teeth & mucosa

5. Functions of Major Connector
Cross-Arch Stabilization * (Counterleverage)
Bracing elements on one side of the arch providing stability to the other
Cross -arch stabilization: resistance against dislodging or rotational forces obtained by using a partial removable dental prosthesis design that uses natural teeth on the opposite side of the dental arch from the edentulous space to assist in stabilization.

6. Requirements of Major Connector
Rigidity *
Functions as one unit
To distribute forces effectively over the entire supporting structures.
To resist flexing and torque that could be transmitted to the abutments and other structures as destructive forces

7. To Increase Rigidity Use a more rigid alloy Shape (cross-section)
Chrome-cobalt > gold alloys; cast > wrought
Shape (cross-section)
1/2 round > 1/2 pear shaped > flat bars

8. To Increase Rigidity Increase the bulk as the length increases
Corrugate linguoplate or rugae areas

9. Requirements Non-Interference with soft tissues
Should not enter undercut areas
avoid by changing path of insertion
or by using blockout

10. Non-Interference With Tissues
Avoid terminating on:
Free gingival margin
Cross abruptly at 90o
Relief is used to minimize impingement

11. Borders of maxillary connector should be placed a minimum of 6 mm away from and parallel to the gingival margins. Border of mandibular connector should be located a minimum of 4 mm below the gingival margin

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

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

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

15. Unobtrusive *
Smooth transition from connector to denture base - butt joint
not noticeable or conspicuous

16. Unobtrusive Line angles and edges should be smooth and rounded
Borders should not interfere with speech

17. Relief
Mandibular major connectors should be located and/or relieved to prevent impingement of tissue because the distal extension denture rotates in function.
Except for a palatal torus or prominent median palatal suture area, maxillary connectors ordinarily require no relief.

18. Mandibular Major Connectors
Lingual Bar
Lingual Plate
Sublingual bar
Lingual bar with cingulum bar (continuous bar)
Labial bar
Swing lock design

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

20. 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)

21. Lingual Bar
Located above moving tissue but as far below the gingival tissue as possible
The superior border should be tapered toward the gingival tissue superiorly with its greatest bulk at the inferior border, resulting in a contour that is a half-pear shape.

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

23. Inferior Border of Lingual Bar *
Patient lifts tongue
Activates floor of mouth
Measure from tip of probe to free gingival margin OR
Make impression
with lifted tongue
Measure on cast
Locate the inferior border as far inferiorly as possible to avoid interference with the resting tongue and trapping of food; without exceeding the functional depth of lingual vestibule.

24. Inferior Border of Lingual Bar

25. Lingual Bar Position Superior border 3-4 mm or more below FGM
As far from gingival margin as possible

26. Mandibular Major Connector Relief
Eliminates impingement
Wax spacer (relief) placed under major connector
One thickness of 30 gauge wax *
0.010“ inch or 0.25 mm thickness

27. Lingual Bar Indication
The lingual bar should be used for mandibular RPD where sufficient space exists between the slightly elevated alveolar lingual sulcus and the lingual gingival tissue (more than 8 mm)

28. Contraindications for Lingual Bar
Remaining natural anterior teeth severely tilted lingually
Interfering lingual tori
High attachment of lingual frenum
Interference with elevation of the floor of the mouth during functional movements (< 8 mm)

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

30. Lingual Plate
Inferior border at the ascertained height of the alveolar lingual sulcus when the patient's tongue is slightly elevated.

31. Lingual Plate Rest at each end of lingual plate
Prevents forces being directed facially
Easier denture tooth addition than bar *
Linguoplate is indicated when the future replacement of one or more incisor teeth will be facilitated by the addition of retention loops to an existing linguoplate

32. Lingual Plate Variations
May show through embrasures

33. Lingual Plate Indications
Potential Impingement from lingual bar
High floor of the mouth (< 8 mm)
Prominent lingual frenum
Lingual tori

34. Lingual Plate Indications
The residual ridges in Class I arch have undergone such vertical resorption that they will offer only minimal resistance to horizontal rotations of the denture through its bases.
For using periodontally weakened
teeth to furnish support to prosthesis and to help resist horizontal rotation of the distal extension type of denture. (act as periodontal splint)

35. Lingual bar with secondary bar on cingula of anterior teeth *
Mandibular Lingual Bar with Continuous Bar (Cingulum Bar) (Kennedy Bar, Double Lingual Bar)
Lingual bar with secondary bar on cingula of anterior teeth *
Originates bilaterally from incisal, lingual, or occlusal rests of adjacent principal abutments.

36. Mandibulat Lingual Bar with Continuous Bar Indications
When a linguoplate is otherwise indicated but the axial alignment of anterior teeth is such that excessive blockout of interproximal undercuts would be required.
When wide diastema exists between mandibular anterior teeth and a linguoplate would objectionably display metal in a frontal view.

37. Mandibulat Lingual Bar with Continuous Bar
Potential food trap between two bars
Normally avoid

38. Labial Bar Extreme lingual inclination of the remaining teeth *
Indications are rare
Swing-lock design (Hinged Continuous Labial Bar) is a variation
Or When severe lingual tori cannot be removed and prevent the use of a lingual bar or lingual plate major connector

39. Maxillary Major Connectors
Anterior-Posterior Palatal Strap
Palatal plate-type connector
Single palatal strap
U-shaped palatal connector (Anterior Palatal Strap)
Single palatal bar
Anterior-posterior palatal bar

40. Maxillary Major Connectors
Whenever it is necessary for the palatal connector to make contact with the teeth for support, definite tooth support by definite rest seats should be provided *
Because major connector components resting on unprepared inclined tooth surfaces can lead to slippage of the denture or to orthodontic movement of the tooth, or to both.

41. Maxillary Major Connectors
Terminate 6.0 mm or more from free gingival margin when possible

42. Anterior-Posterior Palatal Strap*
Maximum rigidity
Minimum bulk
Use in most cases
Especially torus palatinus
Relatively narrow (8 to 10 mm) anterior and posterior palatal straps. Lateral palatal straps (7 to 9 mm) broad and parallel to curve of arch.
Anterior border of this strap should be located just posterior to a rugae crest or in the valley between two crests.

43. Anterior-Posterior Palatal Strap Indications
Class I and II arches in which excellent abutment and residual ridge support exists, and direct retention can be made adequate without the need for indirect retention.
Long edentulous spans in Class II, modification 1 arches.
Class IV arches

44. Anterior-Posterior Palatal Strap Indications
Inoperable palatal tori that do not extend posteriorly to the junction of the hard and soft palates.
The only condition preventing its use is when there is an inoperable maxillary torus that extends posteriorly to the soft palate.

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

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

47. Palatal Plate-Type Connector
Covers one half or more of the hard palate
Maximum tissue support
Connector of choice in long distal extension cases

48. Palatal Plate-Type Connector
Greater stability and stress distribution
Not used with torus
Increases retention

49. Palatal Plate-Type Connector
Connector should:
be fabricated of uniformly thin metal *
have accurate anatomic reproduction of the rugae
improves strength and rigidity
Thermal conductivity makes it more acceptable for the tongue and the underlining tissues

50. Palatal Plate-Type Connector
Connector should:
Cover same area as complete denture posteriorly
Have large surface area of mucosal contact
improves potential for retention

51. Palatal Plate-Type Connector Forms
A cast plate between two or more edentulous areas
A complete or partial cast plate that extends posteriorly to the junction of the hard and soft palate

52. Palatal Plate-Type Connector Forms
3. An anterior palatal connector with a provision for extending an acrylic resin denture base posteriorly

53. Palatal Plate-Type Connector Indications
Abutments are periodontally involved
Maximum stress distribution is needed*
Flabby tissue
Shallow palatal vault
1. Class I arch with one to four premolars and some or all anterior teeth remaining, and abutment support is poor and cannot otherwise be enhanced; residual ridges have undergone extreme vertical resorption; direct retention is difficult to obtain.
2. Class II arch with a large posterior modification space and some missing anterior teeth.
3. Six or less anterior teeth remain

54. Single Palatal Strap Usually use for Class III & IV cases *
Bilateral edentulous spaces of short span in a tooth-supported restoration, particularly when the edentulous areas are located posteriorly.
Should not be used to connect anterior replacements with distal extension bases

55. Single Palatal Strap
Strap should be 8mm wide or approximately as wide as the combined width of a maxillary premolar and first molar.
Confined within an area bounded by the four principal rests

56. Single Palatal Strap
Never use in cases involving distal extensions since it must be made bulky for rigidity
Relief may be required over bony midline
Not used with torus

57. Palatal Bar Don’t use Narrow anterio-posteriorly
Thick occluso-gingivally
Palatal bar objectionable due to bulk
Less than 8 mm in width, thin, flexible

58. 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

59. U-Shaped or "Horse-Shoe" Palatal Connector
Too flexible
Allows movement at the posterior
Traumatic to the residual ridge
Use only where torus prohibits other connector & extends to the posterior limit of the hard palate

60. Flexes, impinging on soft tissue

61. References
Chapter 5 Major and Minor Connectors, McCracken's Removable Partial Prosthodontics, 11th edition