The document discusses the design and specifications of mandibular major connectors used in removable dental prostheses, detailing various types such as lingual bars, sublingual bars, and cingulum bars. It highlights essential requirements, placement considerations, and advantages and disadvantages of each connector type, including specific indications and contraindications for their use. Additionally, the document covers non-rigid connectors and their principles, as well as a summary of suitable major connectors for different clinical scenarios.

1. Dr. Ishaan Adhaulia

2. Contents
 Introduction
 Definition
 Basic requirements of mandibular major
connectors
 Types of mandibular major connectors
 Design sequence for mandibular major
connectors
 Non – rigid connectors
 Summary

3. Introduction
 Major Connector The part of a partial removable
dental prosthesis that joins the components on one
side of the arch to those on the opposite side (GPT 8)
 Basic requirements of a mandibular major connector:
• Rigid & provides cross-arch stability - broad
distribution of stress.
• Should not interfere with & non irritating to the
tongue.
• Should not alter the contour of the lingual surface of
the mandibular alveolar ridge.
• Should not impinge on the oral tissues when the
prosthesis is inserted or rotate in function.

4. Design Specifications
Placement of borders: The superior borders
are placed atleast 3 mm from the gingival
margins.
Relief: To prevent tissue impingement at rest
& during function.
 Tooth-borne prostheses: 30 guage,0.010
inches.
 Tooth/tissue-borne prostheses: More relief
is required.

5. Relief required for tooth/tissue-
borne prostheses depends
upon :
a) Relationship of fulcrum line to major connector:
1) When the fulcrum line is posterior to the major connector,
less relief is required (28 guage,0.013 inches to 26 guage,
0.016 inches)

6. 2) When the fulcrum line is anterior to the major connector,
more relief is required (26 guage,0.016 inches to 24
guage,0.020 inches)
3) Shape of adjacent alveolar ridge: The lingual slope of
the alveolar ridge influences the amount of relief
required, due to the rotation of the prosthesis tissue-
wards.

7. Quality of supporting structures
1) Periodontal status of abutment
teeth
2) Quality of the supporting soft
tissues
3) Bone index
4) Movement of the dento-alveolar
segment
5) Lingual tori

8. Types of mandibular major
connectors
 Lingual bar
 Sublingual Bar
 Cingulum Bar (Continuous bar)
 Lingual bar with cingulum bar
(Continuous Bar)
 Linguoplate
 Labial Bar
 Hinged Continuous Labial Bar

9. Lingual Bar Major
Connector
 Indications: 8mm vertical space between gingival margin and
floor of the mouth.
 Contraindications: Inoperable lingual tori. High lingual frenum
attachment. Interferences during functional movements of the
floor of the mouth
Characteristics and location
 Half-pear shaped with bulkiest portion inferiorly located.
 Superior border tapered to soft tissue.
 Superior border located at least 3mm inferior to gingival
margins.
 Inferior border located at the ascertained height of the alveolar
lingual sulcus when the patients tongue is slightly elevated.

10. At least 8mm of vertical space between the active
tissues of the floor of the mouth and the gingival
margins of the teeth is required.
 Advantages
It may be flexible if poorly
constructed. Lingual bar
connector has minimal tissue
coverage and has minimal
contact with oral tissues.
 Disadvantages
Rigidity is less compared to a
well constructed lingual plate. It
does not contact the teeth, so
decalcification of the tooth
surface is minimized.

11. Block out & relief of master cast
 All tissue undercuts parallel to path of
placement
 An additional thickness of 32-gauge wax
when the lingual surface of the alveolar ridge
is either undercut or parallel to the path of
placement.
 No relief is necessary when the lingual
surface slopes inferiorly and posteriorly.

12. Lingual Plate
Indications:
 High lingual frenum , shallow
vestibule.
 Severe vertical resorption
 Presence of lingual tori.
 Stabilization of periodontally weak
teeth.
Contraindications:
 In lingually inclined mandibular
anterior teeth.
 Wide embrassures and diastema

13. Characteristics & 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; and
interproximally to contact points.
 Scalloped contour of apron as dictated by
interproximal blockout.

14. The superior border should be knife edge and contoured to
intimately contact lingual surface above the cingula.
Close inter proximal space to level of contact points.
ADVANTAGES
 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.
 Provision to include more teeth in the
design

15. 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
BLOCKOUT & RELIEF
•All involved undercuts of contacted teeth parallel to
the path of placement.
•All involved gingival crevices.
•Lingual surface of alveolar ridge

16. Double Lingual Bar
 This type of major connector is also
called “Kennedy bar” 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.

17. Characteristics & Location
 The lower component
displays same
charecteristics as that of a
lingual bar.
 The upper bar should be half
oval ,2-3mm in height and
1mm thick, presenting
scallopped appearance.
 Two bars joined by minor
connectors on each end

18. Advantages
 Effectively extends indirect retention in an anterior
direction.
 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

19. Blockout & Relief
 Same as for lingual bar.
 No relief for continuous bar except
blockout of interproximal spaces

20. Sublingual Bar
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.

21.  Accurately record the functional depth and
width of the lingual sulcus
 These sulcus dimensions are retained on
the master cast resulting in a bar whose
maximum cross-sectional dimension is
oriented horizontally.
 Rigidity
Height ~ Rigidity2
Width ~ Rigidity3
 The increased width of the sublingual bar
connector therefore ensures that the
important requirement of rigidity is satisfied.

22. Continous Bar (Cingulum
Bar)
Indication:
 Improper axial alignment of
the anterior teeth requiring
excessive blockout of
interproximal undercuts.
Contraindications:
 In lingually tilted anterior
teeth.
 Wide diastema between
mandibular anterior teeth.

23. Cingulum Bar Characteristics And
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.
BLOCKOUT & RELIEF
 No relief for cingulum bar except
interproximal spaces.

24. Labial Bar
Indication:
 Large inoperable lingual
tori.
 Severe & abrupt lingual
undercuts.
 Lingually inclined lower
anterior & premolars.

25. Characteristics And
Location
 Half-pear shaped with bulkiest portion
inferiorly located on the buccal aspect.
 Superior border tapered to soft tissue and
4mm inferior to labial gingival margins.
 Inferior border located in the labial buccal
vestibule; at the junction of attached & mobile
mucosa.

26. BLOCKOUT & RELIEF
 All tissue undercuts parallel to path of
placement and when the labial surface
is either undercut or parallel to the path
of placement.
 No relief if labial surface of alveolar
ridge slopes inferiorly.

27. Hinged Continuous Labial
Bar
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.

28. Characteristics And
Location
 • This type of major connector is the
modification of linguoplate which is
incorporated in the “Swing-lock”
 Design consists of labial bar i.e. connected to
the major connector by hinge on one end and
latch at the other end.

29. Design of Mandibular Major Connectors
 Step I-Outline the basal seat areas on the
diagnostic cast.
 Step II-Outline the inferior border of the major
connector.
 Step III-Outline the superior border of the major
connector.
 Step-IV-Connect the basal seat area to the
inferior and superior borders of the major
connector and add minor connectors to retain the
acrylic resin base.

30. Design of Mandibular Major Connectors
Step 1
Step 2
Step 3
Step 4

31. NON RIGID
CONNECTORS
 Split Bar major Connector
 Ticonium Hidden Lock Partial Denture
 The 12 Gauge Chrome Wire Stress
Breaker
 Disjunct Dentures

32. Split Bar Major Connector
 Split is provided between the denture base
area and the major connector
 When occlusal forces are applied they are
transferred more towards the tissue
supported base and then they are transmitted
to the abutment teeth.

33. Ticonium Hidden Lock Partial
Denture
 This is a two piece casting, the top half, which
is the major connector supporting the direct
retainers and other rigid components, is cast
first.
 The bottom half, which is the connector
between the denture bases, is cast to the
major connector next.

34.  The hidden lock is created by mechanical
means, and the split between the two
connectors is made possible by the thin oxide
shell that forms during the making of the two
sections.
 What appears to be a conventional lingual bar
or linguoplate actually is two bars connected by
a movable joint at the midline

35. The 12 Gauge Chrome Wire Stress
Breaker
 The 12 gauge chrome wire stress
breaker avoids the complexities of most
stress breaker designs and yet offers
many clinical advantages.

36.  The 12 gauge wire is
adapted to the refractory
cast. The wire is coated
with die lubricant and the
wax up is completed.
 The wax must not go
beyond the maximum
convexity of the wire.
 The wire is removed and
the casting is completed.

37.  After recovering the casting the wire is
welded or soldered
ADVANTAGES
 The rigidity of the 12 gauge wire avoids
overloading the mucosa.
 The mucosa is also more evenly loaded
 It is easy to splint teeth with this design.
 The fabrication is relatively simple.
 Repairs are rarely needed and are also
simple.

38. Disjunct Dentures
Principle:
 Tooth borne & mucosa-borne parts of denture
are disjoined.
 Tooth borne part providing splinting of remaining
teeth & only retention for mucosa borne part.
Structural details:
 The tooth borne part is a lingual plate and thus
provides stabilization for the remaining teeth.
 The tissue borne part is a lingual bar which
consists of denture bases along with the teeth at
its terminals.

39. Advantages:
 Independent movement between the tooth
supported and tissue supported parts
decreases the forces on periodontally
weakened remaining teeth.
Disadvantages :
 It is technically difficult to fabricate o Patient
may complains of rattling of the framework
during mastication.

40. Disadvantages of non rigid major connectors:
 The broken stress denture is usually more
difficult to fabricate and therefore more costly.
 Vertical and horizontal forces are concentrated
on the residual ridge, resulting in increased
ridge resorption. Many stress breakers
designs are not well stabilized against
horizontal forces.
 If relining is not done when needed, excessive
resorption of the residual ridge may result.

41. Summary
 For a tooth supported removable partial denture the
lingual bar is the suitable major connector.
 Long span edentulous ridges in which there is
posterior abutment and indirect retention is needed,
the lingual plate is indicated.
 When anterior teeth are periodontally treated and
needs support and stabilization, the lingual plate or
double lingual bar may be used.
 When the tissue of the floor of the mouth are active
and <8mm space available between tissue and
marginal gingiva, a lingual plate is preferred.