in Prosthodontics

1. MAXILLARY MAJOR CONNECTORS
Guided by:
Dr. U.M. Radke Dr. N.A. Pande Dr. S Deshmukh
HOD & Guide Professor Reader
Dr. T.K. Mowade Dr. R. Banerjee DR. A. Chandak
Reader Reader Reader
Presented by:-
Dr. Richa Sahai
II MDS

2. Contents
• Introduction
• Types of major connectors
• Ideal Requirements of the major connector .
• Maxillary Major Connectors
• Structural requirement for maxillary major connector
• Types and designing of maxillary major connector
• Non-rigid maxillary major connectors
• Prosthodontic Considerations
• Recent advances
• Conclusion
• References

3. DEFINITION:
A major connector is the unit of the partial denture that connects the parts of the
prosthesis located on one side of the arch with those on the opposite side.

4. Chief Functions :
1. Unification of the major parts of the prosthesis.
2. Distribution of the applied force throughout the arch to selected
teeth & tissue.
3. Minimization of torque to individual teeth.

5. MATERIALS USED FOR MAJOR CONNECTORS
The various alloys that can be used in constructing removable
partial denture framework are:
• Type lV gold alloy
• Nickel chromium
• Cobalt-chromium
• Co- Cr- Ni
• Titanium and its alloys

6. Types of major connectors:
• Based on the site:
1. Maxillary major connector
2. Mandibular major connector
• Based on rigidity:
1. Rigid major connectors
2. Non rigid major connectors

7. IDEAL REQUIREMENTS OF THE
MAJOR CONNECTOR
1. It should be rigid.
2. It should not impinge on free gingival margin and other soft tissues.

8. 3.
4. Should not allow food lodgment beneath it.
5. Vertical support
6. Indirect retention

9. 7.Should enable to place the denture bases where required.
8. Should be comfortable to the patient.
9.Should be made with a material, which is biocompatible.
10.
11

10. Location :
1. Should be free of movable tissues
2. Impingement of gingival tissues is avoided
3. Bony and soft tissue prominences should be avoided during placement and
removal
4. Relief should be provided beneath a major connector

12. Selection of a major connector for the
extension-base removable partial denture
Factors :
1. The degree to which the removable partial denture must be
supported by structures other than the natural teeth.
2. The degree of rigidity required of the major connector to
adequately distribute functional stresses from one side of the arch
to the other.

13. Primary Factors
1. Support.
• It is partly dependent upon the hard palate.
• The greater the coverage of the hard palate, the greater the support
received from the palate.
• Thus, the ‘‘snowshoe’’ principle is in effect in that the stress load is
distributed over a large area, and the force per unit area is reduced.
J Prosthet Dent 2005;94:207-8.

14. 2. Rigidity.
• It is enhanced by the joining of the anterior and posterior bars to form
a circle.
• This union makes the major connector more than twice as rigid as each
bar would be individually.
• Additional rigidity is obtained by use of the ‘‘L’’ beam effect, i.e., metal
lying in two different planes.
J Prosthet Dent 2005;94:207-8.

15. “ L “ BEAM EFFECT
• This principle is applicable to the anteroposterior palatal bar or strap
major connector
• In this component there are two bars/strap lying perpendicular to each
other.
• The anterior and posterior bars are joined by flat longitudinal elements on
each side of the lateral slopes of the palate

17. Special Structural Requirements for Maxilla Major
Connector
• The borders should not be harmful to the tongue.
• The beading is provided for special seal and the beading should be of
about 0.5 mm in both width and depth.
• The tissue side of the maxillary major connector is not highly polished, to
preserve the intimate tissue contact, which aids in retention and stability.
• It should cross the palate at right angle rather than diagonally.

19. 1. SINGLE PALATAL STRAP
• Most versatile.
• Most widely used.
• Relatively narrow for tooth supported prosthesis.
• Much wider for longer edentulous space.
• Broad when edentulous area is located posteriorly.

20. • Should not be less than 8 mm wide or its rigidity may be compromised.
• Suitable rigidity without excessive bulk may be obtained by casting a 22
gauge matte plastic pattern
• It should be made wide and thin rather than narrow and thick.
• Wider palatal strap, the vaguer the difference between it and a modified
complete palate.
• Wide palatal strap may be used for a unilateral extension but rarely used in
bilateral situations.

23. 2.SINGLE PALATAL BAR
 Narrow
 Half round.
 Thickest at the center

26. 3. U-SHAPED PALATAL CONNECTOR (Horseshoe shaped connector)
 It consists of thin band of metal running along posterior teeth and extending
onto the palatal tissues for 6-8mm.

27. Design consideration
• Borders – 6 mm from gingival margin Or Extend onto the lingual surfaces of the
teeth .
• Lateral borders – At the junction of vertical and horizontal slopes of the palate.
• Must be symmetrical
• As thin as possible
• Natural rugae should be reproduced in metal ( to minimize the possibility of
phonetics difficulties)
• Posterior border slightly beaded except over an unusually prominent median raphe.

28. INDICATIONS
• Large inoperable tori, prominent medial suture.
• Multiple anterior teeth are to be replaced.
• Patients with exaggerated gag reflex.
• Periodontally weakened anterior teeth

30. 4. ANTERIOR AND POSTERIOR PALATAL BAR-TYPE CONNECTORS
 The two bars are joined by flat longitudinal elements on each side of the lateral slopes
of the palate thus providing 2 bars at different planes “L beam effect”.

31. • Excellent rigidity
• Little support
• Rely almost exclusively on support from the remaining teeth.

32. Design consideration
Anterior bar –
- Flat & narrower than palatal strap
- Anterior border positioned on valley of rugae never on crest
- 24 to 26 gauge wax.
Posterior bar –
- Half oval shaped
- Well back in the palate just anterior to vibrating line.
- 22 to 26 gauge wax.

35. 5. ANTERIOR AND POSTERIOR PALATAL STRAP-TYPE CONNECTOR
(Closed Horseshoe Connector)
 Structurally strong and rigid
Used in most maxillary partial dentures (almost any)

37. DESIGN CONSIDERATIONS
• Uniform borders 6 mm away from free gingival margin or should extend on the
lingual surface of the teeth.
• Anatomic replica pattern or matte surface forms of 22 gauge thickness.
• A strap of 22 gauge thickness , 8-10mm wide

39. 6.PALATAL PLATE-TYPE CONNECTOR
The full palate connector should be thin, with the natural anatomy of the
palate reproduced and covering one half or more of the hard palate.

43. The term used to denote the scribing of shallow groove on the
maxillary master cast outlining the palatal major connector
exclusive of rugae area.
Purposes :
Beading of Maxillary Cast

44. DESIGNING OF MAXILLARY MAJOR CONNECTORS
• In 1953, Blatterfein described a systematic approach to designing maxillary
major connectors.
• With a diagnostic cast in hand and knowledge of the relative displaceability of
the tissue covering the median palatal raphe, the following basic steps are
recommended:

45. STEP 1. Outline of primary bearing areas:
STEP 2. Outline of nonbearing areas.STEP 3: Outline of connector areas
Step 4: Selection of connector type
STEP 5 : Unification

47. • It is suggested as a means to allow the base to move slightly
with less strain to the abutments
Advantages:
• Allows the independent movement of partial denture and the abutment
teeth.
• By this independent movement most of the occlusal forces directed
towards the stronger residual ridge and very less forces are directed
towards the periodontally weak abutment teeth .

48. • Bernard Levin has given the rules for selecting the rigid or non rigid type of major
connectors.
• They are:
Rule 1: If the teeth are periodontally sound and the residual ridge is poor “Rigid
Connector’s” are indicated.
Rule 2: If the teeth are periodontally weak and the residual ridge is strong “Non
rigid” (stress breakers type) connector’s.

49. Types of maxillary non rigid connectors
1. Soldered Split Palatal Connector
- In this design the maxillary major connector is split during the wax pattern stage
and then casted.
- After recovering the framework the two parts are soldered by leaving a split.

50. 2. Split Palatal Plate:
- In this design the major connector is cut partially during the wax pattern stage
- The cut is made by a sharp scalpel blade at the junction of the edentulous
area and the tooth supported area
- During loading the denture base will move vertically with equal force on the
soft tissues

51. Disadvantages of non rigid major connectors:
1. The broken stress denture is usually more difficult to fabricate and
therefore more costly.
2. Vertical and horizontal forces are concentrated on the residual ridge,
resulting in increased ridge resorption.
3. If relining is not done when needed, excessive resorption of the residual
ridge may result.

52. 4. The effectiveness of indirect retainers is reduced or eliminated altogether.
5. Spaces between components are sometimes opened up in function, thus
trapping food.
6. Flexible connectors may be bent and distorted by Careless handling. Even a
slightly distorted connector may bring more stress to bear on the abutment
7. Repair and maintenance of any stress breaker is difficult, costly, and frequently
required.

53. Study: 1
• JPD (1989)- “Rigidity of major connectors when subjected to
bending and torsional forces” BY : Z .Ben-ur,S Matalon,Aviv and
Cardash
• The rigidity of five maxillary major connector with different cross
section were tested by using a micrometer microscope and a system
of pulley and weight.
• Concluded that – in maxillary non rigid major connectors - most rigid
was the A-P palatal bar ,and the most flexible is the U shaped palatal
bar.

54. Study:2
• Zeen Ben et al (JPD) 1999;81;526-532: Stiffness of different design and
cross section of maxillary major connector of removable partial denture
• Conclusion –
1. In the U-shaped maxillary major connectors, the arch length should be
designed as short as possible without compromising occlusal support. It
is advisable to end the dentate arch at the first molar.
2. In the maxilla, to achieve maximum resistance to functional forces, the
major connector should be designed to transverse the maxilla opposite
the edentu- lous ridge which is the area of maximum load.

55. 3. The anteroposterior palatal bar in different planes is the preferred
design for obtaining maximum stiffness in the maxillary major connector.
The U-shaped design is less desirable.
A.P. Strap was stiffest, which could bear 80-100 N/mm2 forces in
premolar region and Horseshoe shaped major connector – Least stiffest
which could bear 40-55 N/mm2 forces in premolar region.

56. Study 3:
• Yuuji Sato et al (IJP 1990) reported that the flexural rigidity of the
major connectors can be obtained by the following formula:
EWT
• Flexural rigidity of major connector = ---------------
12
Where, E = Modulus of elasticity of the alloy.
W = Width in mm,
T = Thickness.
• They concluded that, for Co-Cr palatal Bar minimum thickness = 1mm,
minimum width 10 mm, and also provided the thickness for various
widths of major connectors.

57. Study 4 :
• Mc cracken w. L 1958: “ JPD; 8;71-84. “Contemporary partial denture
design “ – said that , Single palatal strap is the most preferred major
connector.
• It provides rigidity , patient comfort , greater stability, without tissue
damage

58. Study 5:
• JPD;1958;8;71-84, McCracken - said that an arch shaped palatal casting ( U
shaped ) is rarely justified except to avoid a palatal torus, as it must either
be bulky or it is flexible and injurious to the gingival
Study 6:
• Wanger AG and Traweele (1982, JPD 47, 242-245) conducted a study of
comparison of major connectors.
• Reported that the singlee palatal strap was most accepted by the patient
when compared to palatal bar A.P. strap and complete palatal coverage.

59. Prosthodontic principles in the framework design of
maxillary obturator prostheses
• In 1978 the late Dr Mohammed Aramany presented the first
published system of classification of postsurgical maxillary defects.
• This classification system of postsurgical maxillectomy defects is a
useful tool for teaching and developing obturator framework designs
and enhancing communication among prosthodontists.

60. • This article describes a series of Aramany-obturator design templates
and discusses the relevant considerations for each. In all situations, a
quadrilateral or tripodal design is favoured over a linear design
because this allows a more favourable leverage design application
that will aid in the support, stabilization, and retention of the
prosthesis.

67. Periodontally involved teeth
SWING LOCK RPD

68. Patients with Microstomia :
• 2 piece sectional major connector with magnetic retainers – cobalt
samarium magnet .

69. RECENT ADVANCES
1. Use of CAD/CAM technology to fabricate a removable partial denture
framework

73. 2. PEEK – For Major Connectors.
• Strong and lightweight for improved patient comfort
• Digital design matches the patient’s individual anatomy
• The metal-free denture framework is taste-neutral
• Excellent mechanical and chemical properties
• High strength to weight ratio
• Elastic properties similar to human bone
• Zero corrosion rate
• low water absorption
• Radiolucent
• Superior biocompatibility

74. 1.
2.

75. FIG 3
FIG 4

76. Conclusion
• Major connectors by uniting the other components of a removable partial
denture acts like a foundation bringing about bilateral distribution of forces.
• Major connector chosen to suit the individual condition must unite the various
components so that the prosthesis is durable and restores function. And meet
the demand of esthetics .

77. References
1. McCracken’s Removable Partial Prosthodontics-11th Edition- A.B.Carr,
G.P.McGivney , D.T.Brown.
2. Stewart - Clinical Removable Partial Prosthodontics, 2nd Edition.
3. D.M.Watt,A.R.MacGregor- Designing partial dentures
4. Davis Henderson - Major Connectors for Mandibular Partial Denture –J
Prosthet Dent 1973; 29:532-46
5. B.T.Cecconi :Lingual bar design –J Prosthet Dent 1973; 29:635-40.
6. Bernard Levin – Stress breakers :A practical approach: DCNA, 1979;77
7. Randel et al . Cingulum bar.J Prosthet Dent 1991;66;221-29.

78. 6. W.L.McCraken – Contemporary partial denture design. J Prosthet Dent
2004;92:409
7. Selection of Major Connectors – Yuuji et al. IJP 1990; 175-80.
8. Designing the Lingual Bar – Bert T Cecceni. JPD 1973; 29 : 635-40.
9. Major Connectors for Mandibular Partial Dentures – Davis Henderson.
JPD 1973; 29 : 532-46.
10. Lingual Plate as a Reciporcating Component – John W McCartney. JPD
1979; 624-26.
11. Cingulum Bar – Randel et al. JPD 1991; 66 : 221-29.
12. Stiffness of Different Designs of Major Connectors – Zeer Ben et al. JPD
1999; 81 : 326-32.

79. 15. Swing Lock Dentures – Curtis M Bucker. JPD 1981; 46 : 126-131.
16. Photo Elastic Study of Split Palatal Major Connector – Phillip V Reitz et
al. 1984; 51 : 19-23.
17. Stress Breakers : A Practical Approach – Bernard Levin. DCNA 1979; 23
: 77-86.
18. Variabilities in Dentists Designs of Removable Partial Dentures – Wayne
R Frantz. JPD 1973; 29 : 172-182.

80. “ No component of a removable partial denture should be added arbitrarily or conventionally.
Each component should be added for a good reason and to serve a definite purpose.”
-McCracken