removable partial denture

1. Dr PRATHIBHA PRASAD
MDS 1ST YEAR
KCDS
MAJOR CONNECTORS AND MINOR
CONNECTORS

2. CONTENTS
• INTRODUCTION
• COMPONENTS
• MAJOR CONNECTORS
• TYPES OF MAXILLARY MAJOR CONNECTORS
• LOCATION
• MANDIBULAR MAJOR CONNECTORS
• MINOR CONNECTORS
• REVIEW OF LITERATURE
• BIBLIOGRAPHY

3. INTRODUCTION
• Removable partial denture is a removable denture that replaces some teeth in a partially
edentulous arch;that can be readily inserted and removed from the mouth by the patient.-
GPT9
• According to OSBORNE AND LAMMIE RPD can be of three types:
1. Mucosa borne
2. Tooth borne
3. Combination of mucosa borne and tooth borne.

4. COMPONENTS OF A TYPICAL REMOVABLE
PARTIAL DENTURES-
1. Major connectors
2. Minor connectors
3. Rests
4. Direct retainers
5. Stabilizing or reciprocal components (as parts of a clasp assembly)
6. Indirect retainers (if the prosthesis has distal extension bases)
7. One or more bases, each supporting one to several replacement teeth

5. MAJOR CONNECTORS
• The part of a removable partial denture that joins the components on one
side of the arch to those on the opposite side.- GPT9
• A major connector is the component of the partial denture 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 partial denture to which all other parts are
directly or indirectly attached- McCraken

6. CHIEF FUNCTIONS OF MAJOR CONNECTORS
• Unification of the major parts of the prosthesis
• Distribution of the applied force throughout the arch to selected teeth and
tissue.
• Minimization of torque to the teeth.
• Also provides the cross-arch stability to help resist displacement by
functional stresses.

7. ROLE OF MAJOR CONNECTORS IN CONTROL OF
PROSTHESIS MOVEMENT
• If major connector is flexible the ineffectiveness of connected
components jeopardizes the supporting oral structure.
• Can also be manifested by traumatic damage to periodontal
support of the abutment teeth, injury to residual ridges,
impingement of underlying tissue.

8. LOCATION
1.Major connectors should be free of movable tissue.
2. Impingement of gingival tissue should be avoided.
3. Bony and soft tissue prominences should be avoided during placement and
removal.
4. Relief should be provided beneath a major connector to prevent its settling
into areas of possible interference, such as inoperable tori or elevated median
palatal sutures.
5. Major connectors should be located and/or relieved to prevent impingement of
tissue because the distal extension denture rotates in function.

9. DESIRABLE CHARACTERISTICS OF
MAJOR CONNECTORS
1. Rigid
2. Compatible with oral tissues
3. Does not interfere with and is not irritating to the tongue
4. Does not substantially alter the natural contour of the palatal vault.
5. Does not impinge on oral tissues
6. Covers no more tissue than is absolutely necessary
7. Does not contribute to the retention or trapping of food particles .
8. Contribute to the support of the prosthesis.

10. TYPES OF MAJOR CONNECTORS
MAXILLARY MAJOR CONNECTORS
SINGLE PALATAL
BAR
SINGLE PALATAL
STRAP
U-SHAPED
PALATAL
CONNECTOR
ANTERIOR-
POSTERIOR
PALATAL BAR
COMBINATION
ANTERIOR AND
POSTERIOR
PALATAL STRAP-
TYPE CONNECTOR
PALATAL PLATE-
TYPE CONNECTOR

11. STRUCTURAL REQUIREMENTS IN MAXILLARY
MAJOR CONNECTOR

12. SINGLE PALATAL BAR
• A palatal connector component of less than 8 mm in width is
referred to as a bar.
• It is narrow half – oval with its thickest point at the centre
• A partial denture made with a single palatal bar is often either
too thin and flexible or too bulky and objectionable to the
patient's tongue

13. INDICATION
• Limited to replacing one or two teeth on each side of arch and placed no
further anteriorly than the second premolar position.
• Perhaps the only indication for its use is as an interim partial denture until a
more definitive treatment can be considered.
CONTRAINDICATION
• In distal extension situation
• when anterior teeth are to be replaced

14. DISADVANTAGES
• Most difficult for the patient to adjust as to maintain the degree of rigidity it
has to be made bulky.
• Due its narrow anterior-posterior width it derives little vertical support from
the bony palate and must be therefore supported positively by rests on the
remaining natural teeth.
ADVANTAGES
• Used primarily in interim applications.
• Few advantages so should be avoided.

15. SINGLE PALATAL STRAP
• It consists of a wide thin barel of metal that crosses the palate
in an unobtrusive manner.
• It should not be less than 8mm wide or its rigidity maybe
compromised.
• It can be relatively narrow for small tooth supported prosthesis
or wider for larger edentulous spaces requiring support

16. ADVANTAGES
• Because the palatal strap is located in three planes it offers great
resistance to bending and twisting forces.
• Distribution of stress over a broad area.
• Retention of the partial denture is enhanced by the intimate contact
between the metal and soft tissue.
• The strap also contributes some indirect retention.
DISADVANTAGES
• The patient may complain of excessive palatal coverage.
• Another possible disadvantage is an adverse soft tissue reaction in the form of
papillary hyperplasia.

17. INDICATIONS
• Used only when 1 or 2 teeth are being replaced on either side.
• In CLASS III situations
• Need for palatal support is minimal
CONTRAINDICATION
• Anterior replacements with distal extension bases.
the anteroposterior
dimension of a palatal strap
should not be less than 8
mm.

18. U-SHAPED PALATAL CONNECTOR
• It consists of thin band of metal running along posterior teeth and
extending onto the palatal tissues for 6-8mm.
• The borders of the horseshoe connector must either be 6 mm from the
gingival margin or extend onto the lingual surfaces of the teeth.
• The borders should also be placed in the valleys of the rugae.
• The lateral palatal borders should be at the junction of the horizontal
and vertical slopes of the palate.
• The rigidity can be increased by extending the borders slightly onto
the horizontal palate surface.

19. INDICATIONS
• Can be in case of a large inoperable tori
• When several anterior teeth are to be replaced.
• In case of patients with exaggerated gag reflex.
• When periodontically weakened anterior teeth need some stabilizing
support.

20. DISADVANTAGES
 Its lack of rigidity allows lateral flexure under occlusal force.
 induce torque or direct lateral force to abutment teeth.
 Bulk to enhance rigidity results in increased thickness in areas that
are a hindrance to the tongue.

21. ANTERIOR AND POSTERIOR PALATAL BAR-
TYPE CONNECTORS
• The flat anterior bar is narrower than the palatal strap…borders are
positioned in the valleys between the rugae.
• The posterior bar is half-oval, similar to the single posterior palatal bar
connector but less bulky.
• The two bars are joined by flat longitudinal elements on each side of
the lateral slopes of the palate providing an L beam effect

22. INDICATIONS
• When support is not a major consideration and when the anterior and posterior
abutments are widely separated.
• Presence of torus palatinus.
• The patient's mental attitude: the a-p bar may be used as a compromise for the
patient who strongly objects to the greater bulk or area coverage of the full palatal
connector.
CONTRAINDICATIONS
• In reduced periodontal support of the remaining teeth that necessitates additional
support from the palate.

23. ADVANTAGES
 The main advantage is its rigidity. In comparison to the amount of soft
tissue coverage, it is by far the most rigid maxillary major connector
DISADVANTAGES
 it is frequently uncomfortable.
 Derive very little support from the palate.
 May interfere with speech- especially the anterior bar.

24. ANTERIOR AND POSTERIOR PALATAL
STRAP-TYPE CONNECTOR
• A posterior palatal strap should be flat and a minimum of 8 mm wide.
• Posterior palatal connectors should be located as far posteriorly as
possible to avoid interference with the tongue

25. INDICATIONS
• Kennedy’s Class I and CLASS II arches.
• CLASS II modifications I arches.
• Class IV arches.
• In case of inoperable tori.
DISADVANTAGES
• Even though the metal over thin rugae area may be thinner than in
some other major connectors, interference with phonetics may occur
in some patients.
• In addition, the extensive length of borders may cause discomfort to
the tongue

26. PALATAL PLATE-TYPE CONNECTOR
• The full palate connector should be thin, with
the natural anatomy of the palate reproduced.
• The anterior border must be kept 6 mm from
the marginal gingiva or must cover the cingula
of the anterior teeth.
• The posterior border of the complete palate
normally extends to the juncture of the soft and
hard palate.
• The posterior border can be fabricated of either
metal or acrylic resin.

27. • If it is made of metal, the border must be precisely
established, because if overextended it will quickly
induce soreness, and the metal is difficult to alter
satisfactorily.
• A slight bead should be provided in the metal by lightly
scraping the refractory cast, prior to forming the wax
pattern for the framework.
• The acrylic resin border is preferred when maximum
adhesion and atmospheric seal is needed

28. ADVANTAGES
• It reproduces the anatomic contours properly.
• uniform thickness and the thermal conductivity of the metal are readily
acceptable to the tongue and underlying tissues.
DISADVANTAGES
• Adverse soft tissue reaction in the form of inflammation or hyperplasia
may occur
• Problems with phonetics may occasionally occur

29. INDICATIONS
• CLASS I AND CLASS II arches
• When the last remaining abutment tooth on either side of a Class I
arch is the canine or first premolar tooth,
• In individuals with a full complement of mandibular teeth
• When flat or flabby ridges or a shallow vault is present.
• Cleft palate patients
CONTRAINDICATION
• Presence of tori which cannot be surgically removed a full palatal
coverage cannot be given.

30. STRUCTURAL REQUIREMENTS FOR
MANDIBULAR MAJOR CONNECTORS
• Most of the mandibular major connectors are long and relatively narrow because of space
limitation caused by the height of the floor of the mouth, position of lingual frenum.
• For these reasons considerations must be given to maintain rigidity of the connector
without making it so bulky.
• The slope of the lingual tissue and tissue that slope towards tongue requires relief.

31. TYPES OF MAJOR CONNECTOR
Lingual bar Sublingual bar Linguoplate
Lingual bar
with cingulum
bar
Cingulum bar
(continuous
bar)
Labial bar

32. LINGUAL BAR MAJOR CONNECTOR
• The basic form of a mandibular major connector is a half-pear shape, located above
moving tissue but as far below the gingival tissue as possible
• The lingual bar is perhaps the most frequently used mandibular major connector.
• Usually made of reinforced, 6 gauge, half pear shaped wax or a similar plastic
pattern.
• Placement of a lingual bar requires at least 8 mm of space between the gingival
margins and the floor of the mouth

33. Advantages:
• Lingual bar connector has minimal tissue coverage and has minimal contact
with oral tissues.
• It does not contact the teeth, so decalcification of the tooth surface is
minimized.
Disadvantages:
• It may be flexible if poorly constructed.
• Rigidity is less compared to a well constructed lingual plate.
• Cause food entrapment and patient discomfort if it is placed over undercut
• Difficult to use when tori are present

34. Indications:
• It should be used for mandibular removal partial denture where
sufficient space exists between the slightly elevated alveolar lingual
sulcus and lingual gingival tissues.
Contraindications:
• Inoperable lingual tori.
• Highly attached lingual frenum.
• Interferences to elevation of the floor of the mouth during functional
movements

35. LOCATION
• Availability of space for connector is one of the important factor to be considered.
Atleast 8mm of vertical space between the active tissues of the floor of the mouth
and the gingival margins of the teeth is required.
• There are two clinically acceptable methods to determine relative height of the floor
of the mouth to locate the inferior border of the major connector

36. • First method: Patients tongue should touch the vermillion border of the upper lip
and measurements were made in relation to the lingual gingival margins of the
adjacent teeth using a periodontal probe. The readings are transferred to the
master cast.
• Second method: This method uses an individualized impression trays having its
lingual border 3mm short of the elevated floor of the mouth is molded with an
impression material during functional movements of tongue.

37. LINGUOPLATE MANDIBULAR MAJOR
CONNECTOR
• If the rectangular space bounded by the lingual bar, the anterior tooth contacts and
cingula, and the bordering minor connectors is filled in, a lingual plate results.
• A linguoplate should be made as thin as is technically feasible and should be contoured to
follow the contours of the teeth and the embrasures
• A lingual plate may include "step backs" to minimize or eliminate the appearance of metal.
• A lingual plate must be supported by rests located no farther posterior than the mesial
surface of the first premolars.

38. Indications
• When lingual frenum is high or space available for lingual bar is insufficient
• Kennedy Class I where residual ridges have undergone excessive vertical
resorption.
• For stabilizing periodontally weak teeth.
• When future replacement of one or more anterior teeth is predicted.
• Presence of inoperable mandibular tori.
Contraindications:
• In lingually inclined mandibular anterior teeth.
• Mandibular teeth with wide embrassures and diastema

39. Advantages:
• The linguoplate is a rigid mandibular major connector and it provides
more support and stabilization when compared to other connectors.
• Can be used in stabilizing the periodontally-weakened teeth.
• When it is supported at each end by a rest it contributes to the action
of indirect retention.
• When properly contoured and fabricated, it will not cause interference
with tongue movements and will be more comfortable to the patient.
Disadvantages:
• It covers the tooth structure and the gingival tissue.
• The metal coverage of the free gingival tissue prevents physiological
stimulation and self-cleansing of these areas by saliva.

40. LOCATION
 Half-pear shaped with bulkiest portion inferiorly located.
 Thin metal apron extending superiorly to contact cingula of anterior
teeth and height of contour of posterior teeth.
 Scalloped contour of apron as dictated by interproximal blockout.
 The superior border finished to continuous plane with contacted teeth.
 Inferior border at the ascertained height of the alveolar lingual sulcus
when patients tongue is elevated

41. SUBLINGUAL BAR MAJOR CONNECTOR
• A modification of the lingual bar that has been demonstrated to be useful
when the height of the floor of the mouth does not allow placement of
superior border of the connector at least 4-mm below free gingival margin.

42. Indications:
• The height of the floor of the mouth in relation to the free gingival
margin is less than 6mm.
• If it is desired to keep the free gingival margins of anterior teeth
exposed and there is inadequate depth of the floor of the mouth.
Contraindications:
• Lingually tilted remaining natural teeth.
• Inoperable lingual tori.
• High attached lingual frenum

43. LOCATION
• It is same as lingual bar except that the bulkiest portion is located to the
lingual and the tapered portion is towards the labial.
• The superior border of the bar should be atleast 3mm from the free
gingival margin.
• Inferior border is located at the height of the alveolar lingual surface.

44. DOUBLE LINGUAL BAR
• Also known as kennedy bar
• A double lingual bar displays characteristics of both lingual bar and lingual plate major
connectors
• it distribute stresses to all of the teeth with which it comes in contact there by
reducing the stresses to the underlying tissues.
• It is also referred as “continuous lingual clasp” major connector, because of series of
clasp arms connected on the lingual surfaces of lower anterior teeth

45. Advantages:
• The double lingual bar effectively extends indirect retention in an
anterior direction is supported by adequate rest.
• It also contributes to horizontal stabilization.
• It helps in minor amount of support to the prosthesis.
• The gingival tissues and inter-proximal embrassures are not covered
by the connector, which helps in free flow of saliva.
Disadvantages:
• Patient may feel discomfort because it alters the normal position of the
tongue.
• If connector does not maintain intimate contact with tooth surface there
will be food entrapment.

46. 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 exist
Contraindications:
• In severely crowded anterior teeth
LOCATION
• Shaped same as lingual bar.
• Thin narrow metal strap located on cingula of anterior teeth scalloped to
follow interproximal embrassures

47. MANDIBULAR CONTINUOUS BAR (CINGULUM BAR)
• Improper axial alignment of the anterior teeth will necessitate excessive blockout of
interproximal undercuts. These types of cases indicates continuous bar major
connector.
Contraindications:
• In lingually tilted anterior teeth.
• Wide diastema between mandibular anterior teeth
LOCATION
• Thin narrow metal strap located on cingula of anterior teeth, scalloped to follow
interproximal embrassures.
• Originates bilaterally from rests of the adjacent principle abutments

48. LABIAL BAR MAJOR CONNECTOR
• A labial bar runs across the mucosa on the facial surface of the mandibular arch
• Like other mandibular major connectors, a labial bar displays a half-pear shape when
viewed in cross section. But, because of its placement on the external curvature of the
mandible, a labial bar is longer than other mandibular major connector

49. INDICATIONS
• severely lingually inclined lower anterior and premolars prevents the use of other
mandibular major connectors.
• large inoperable lingual tori
• Severe and abrubt lingual tissue undercuts.
ADVANTAGES
• When the remaining mandibular teeth are tipped so far lingually that a more conventional
major connector cannot be used, a labial bar may be considered.
DISADVANTAGES
• Unaesthetic
• Fullness in lower lips
• Patient discomfort

50. LOCATION
• Half-pear shaped with bulkiest portion inferiorly located on the labial or
buccal aspect.
• Superior border tapered to soft tissue and 4mm inferior to labial
gingival margins.
• Inferior border located in the labial buccal vestibule

51. HINGED CONTINUOUS LABIAL BAR
• This type of major connector is the modification of linguoplate which is
incorporated in the “Swing-lock” design consists of labial or buccal bar i.e.
connected to the major connector by hinge on one end and latch at the other
end.
• Support provided by multiple rests on the remaining natural teeth.
Stabilization and reciprocation provided by a lingual plate. Retention is
provided by bar type retentive clasp arms projecting from the labial or buccal
bar and contacting the infrabulge areas on the labial surfaces.

52. Indications:
• Missing key abutments.
• Unfavorable tooth contour.
• Unfavorable soft tissue contours.
• Teeth with questionable prognosis.
Contraindications:
• Poor oral hygiene.
• Shallow buccal labial vestibule.
• High frenal attachment.

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

55. DEFINITION
• The connecting link between the major connector or base of a removable
partial denture and the other units of the prosthesis, such as the clasp
assembly, indirect retainers, occlusal rests or cingulum rests.- GPT9

56. FUNCTIONS OF MINOR CONNECTORS
• Unification and rigidity
• Transfers functional stress to the abutment teeth. This is a prosthesis-to-
abutment function of the minor connector.
• Transfers the effects of the retainers, rests, and stabilizing components
throughout the prosthesis. This is an abutment- to-prosthesis function of
the minor connector
• Maintain a path of insertion

57. FORM AND LOCATION
• Sufficiently bulky to be rigid
• Should be located in the embrasure, where it will be least noticeable to the
tongue.
• Should pass vertically from the major connector so that gingival crossing is
abrupt and covers as little of gingival tissue.
• The deepest part of embrasure should be blocked to avoid interference
during placement and removal.
• Should be thickest towards lingual surface and tapering towards the contact
area

58. TYPES OF MINOR CONNECTORS
Minor connectors that join clasp assemblies to major connectors
Minor connectors that join indirect retainer or auxiliary rests to
major connectors
Minor connectors that join denture bases to major connectors
Minor connectors that serve as approach arms for vertical
projection or bar-type clasps

59. MINOR CONNECTORS THAT JOIN CLASP
ASSEMBLIES TO MAJOR CONNECTORS
• Join clasp assemblies to major connectors must be rigid, because they support the active
components of the removable partial denture, the retentive clasps.
• Support the rests, which prevent vertical movement of a prosthesis toward the underlying
tissues.
• These minor connectors should be broad buccolingually, but thin mesiodistally
• A minor connector should be positioned in the associated lingual embrasure. This results
in a sufficient bulk of metal without encroaching on the tongue space
• Should never be placed on the convex lingual surface of the tooth where its bulk will be
evident.

60. MINOR CONNECTORS THAT JOIN INDIRECT
RETAINERS OR AUXILIARY RESTS TO MAJOR
CONNECTORS
• These minor connectors should form right angles with the corresponding major
connectors, but junctions should be gently curved to prevent stress concentration
• Should be positioned in lingual embrasures to disguise their bulk and promote patient
comfort

61. MINOR CONNECTORS THAT JOIN DENTURE
BASES TO MAJOR CONNECTORS
• These minor connectors must be strong enough to anchor a denture base to the
removable partial denture framework.
• They must be rigid enough to resist fracture and displacement.
• These components must provide minimal interference with the arrangement of artificial
teeth.
• In maxillary distal extension bases, it must extent to cover the tuberosity.
• In mandibular distal extension bases it should extend two-third the length of residual
ridges

62. • MINOR CONNECTORS THAT JOIN THE DENTURE BASE TO
THE MAJOR CONNECTOR MAY BE DESCRIBED AS
FOLLOWS
• Open/ Lattice construction
• Mesh construction
• Bead, wire, or nail-head components on a metal base

63. OPEN/ LATTICE CONSTRUCTION
• Open construction consists of longitudinal and transverse struts that form a ladder-like
network
• Placement of the longitudinal and transverse struts is a critical factor in prosthetic tooth
arrangement.
• In the mandibular arch, one longitudinal strut should be positioned buccal to the crest of
the ridge and the other lingual to the ridge crest.
• In the maxillary arch, one longitudinal strut should be positioned buccal to the ridge crest.
• The border of the major connector generally will act as the second longitudinal strut.

64. • Positioning of a longitudinal strut along the crest of the ridge must be avoided. This not
only interferes with the placement of artificial teeth, but also leads to the denture base to
fracture.
• Transverse struts also must be positioned to facilitate the placement of artificial teeth.
• Ideally, transverse struts should be designed to pass between the necks of the artificial
teeth. This aids in tooth arrangement and often results in improved esthetics.

65. ADVANTAGES
• Used for multiple teeth replacement
• Provides strongest attachment of acrylic resin
• Facilitates rebasing and relining

66. MESH CONSTRUCTION
• Channels that pass through the connector are intended to permit acrylic resin penetration.
• This allows resin encirclement of the minor connector and mechanical retention of the
denture base

67. DISADVANTAGE
• During the packing of acrylic resin, increased pressure is needed to force resin through
the small holes in the minor connector.
• Insufficient packing pressure may result in inadequate resin penetration and a weak
attachment to the framework.
• Also interfere with the arrangement of prosthetic teeth.
• The smaller the openings in this minor connector, the weaker the attachment.

68. BEAD, WIRE OR NAIL-HEAD CONSTRUCTION
• Bead, wire or nail-head components are often used in conjunction with metal denture
bases
• Its is indicated on short-span, tooth supported with well healed ridges

69. • The primary advantage of a metal base is related to improved hygiene and thermal
stimulation.
Disadvantages
• Include difficulty in adjusting and relining cast metal bases.
• Furthermore, the attachment of resin is relatively weak

70. TISSUE STOP
• Integral parts of minor connector designed for retention of acrylic resin bases.
• Used in all distal extension partial dentures using lattice work or mesh retention.
• Provide stability and prevent distortion to framework during packing of acrylic resin.
• Engage buccal and lingual slopes for stability.

71. • Made by removing approximately 2 square mm of the relief wax used to
create space beneath the lattice work or mesh from the point where the
posterior end of minor connector crosses the centre of the ridge.
• During waxing this little depression is waxed as a projection of latticework or
mesh.

72. RELIEF
• Mechanical retention of denture base resin
• Allows the acrylic resin to flow under the construction
• Relief wax is placed in the edentulous areas of 1 mm

73. FINISH LINES
• The planned junction of different materials- GPT9
• In RPDs it denotes the junction of acrylic resin denture base and metal major connector.
1. Internal
2. External
If they are located on the outer surfaces of major connectors, they are called external
finish lines.
If they are positioned on the inner or tissue surfaces, they are termed internal finish lines

74. • Internal finish lines are formed as a result of relief wax placed on the edentulous ridges
of a master cast prior to duplication.
• The relief wax (24 to 26 gauge) creates an elevated area on the resultant refractory cast.
• The margins of the relief wax establish internal finish lines in the completed metal
framework. The margins of the relief wax should be sharp and well defined

75. • External finish lines also must be sharp and should be slightly undercut to help lock the
acrylic resin to the major connector.
• The internal angle formed at the junction of the major or and minor connectors should be
less than 90 degrees.
• The contour of the external finish line should be consistent with the contours of the major
connector.
• Transition from the external finish line to a denture base should be smooth and flowing

76. APPROACH ARM MINOR CONNECTOR
• This serves as an approach arm for a bar clasp, supports a direct retainer and engages
an undercut from the gingival margin.
• Only minor connector that is not required to be rigid.
• Should be smooth, even and taper from its origin to its terminus

80. Caution is urged in considering the lattice
retainer, because the possibility of metal
failure and deformation appears much
greater than with mesh retainers.
bead or nail head retention produced
ineffective acrylic resin retention
Mesh retention is suggested for most
situations, and buccal and lingual
reinforcement is advised when space is
available and tooth position or
length will not be compromised

83. • Designs of removable partial dentures are suggested to affect the mobility of abutment
teeth and removable partial denture (RPD) during oral functions. This study aimed to
examine the effect of direct retainer and major connector designs on RPD dynamics under
simulated loading
• it was revealed that compared with the resin connector, the Co–Cr major connector
caused a significantly smaller distal movement of both denture base and abutment tooth
• that a rigid major connector can distribute the occlusal force across the dental arch,
thereby decreasing the load on the side ipsilateral to loading point

89. COMPARISON OF ADAPTATION BETWEEN THE MAJOR
CONNECTORS FABRICATED FROM INTRAORAL DIGITAL
IMPRESSIONS AND EXTRAORAL DIGITAL IMPRESSIONS
• The objective was to compare the adaptation between the major connectors
of removable partial dentures derived from intraoral digital impressions and
extraoral digital impressions. Twenty-four volunteers were enrolled. Each
volunteer received an intraoral digital impression and one extraoral digital
impression digitized from conventional gypsum impression. A software was
used to create the major connectors on digital impression datasets.
• After all the virtual major connectors designed from Group intraoral digital
impressions (Group I) and Group extraoral digital impressions (Group E)
were directly fabricated by 3D printing technique, the adaptation of the final
major connectors in volunteers’ mouths were measured

90. • .
Place the major connectors in the mouth and measure the intraoral adaptation
of the major connectors with light body silicone impression materials
Landmark points on the layer of the
polysiloxane impression material.

91. • The adaptation of major connectors in Group I were found better at the midline palatine
suture while the adaptation of major connectors in Group E were found better at the two
sides of the palatal vault. In both groups, the highest accuracy in adaptation was revealed
at the anterior margin of the major connectors.
• It is feasible to manufacture the major connectors by digital impression and 3D printing
technique. Both the adaptation of the two kinds of digital impressions were clinical
acceptable.

92. CONCLUSION
• Major connectors by uniting the other components of a removable partial dentures
acts like a foundation bringing about bilateral distribution of forces which depends on
the rigidity of the connector.
• Utmost care should be taken to prevent a major connector from interfering with
normal functions or having any damaging effects to the remaining oral structure.
• Minor connector Connects components to the major connector, Direct retaine,r Indirect
retainer& Denture base

93. REFERENCES
• Stewart’s Clinical Removable Partial Prosthodontics, Fourth Edition
• McCracken's Removable Partial Prosthodontics 12th Edition
• Wagner AG, Traweek FC. Comparison of major connectors for removable partial dentures.
The Journal of prosthetic dentistry. 1982 Mar 1;47(3):242-5.
• Brown DT, Desjardins RP, Chao EY. Fatigue failure in acrylic resin retaining minor
connectors. The Journal of prosthetic dentistry. 1987 Sep 30;58(3):329-35.
• Ben-Ur Z, Matalon S, Aviv I, Cardash HS. Rigidity of major connectors when subjected to
bending and torsion forces. The Journal of prosthetic dentistry. 1989 Nov 1;62(5):557-62.
• Ben-Ur Z, Mijiritsky E, Gorfil C, Brosh T. Stiffness of different designs and cross-sections
of maxillary and mandibular major connectors of removable partial dentures. The Journal
of prosthetic dentistry. 1999 May 31;81(5):526-32.