Prostho main topic

1. MAJOR CONNECTORS

2.  The major connectors connect the
parts of the prosthesis located on
one side of the arch with those on
the opposite side. All other parts of
the partial denture are attached to
it either directly or indirectly.

3.  Be rigid
 Provide vertical support and protect the soft tissues
 Provide a means of obtaining indirect retention
where indicated
 Provide an opportunity of positioning denture
bases where needed
 Maintain patient comfort

4.  First requirement is rigidity. If it will be
flexible, there will be more resorption in
edentulous ridge and periodontal breakdown
of abutment teeth.
 Second requirement is that it must avoid
impingement of the free gingival margin.
 The border should run parallel to gingival
margin of teeth. If it needs to be crossed than
it must be at right angle. Whenever it cross
the gingival margin, relief or space is
required between metal plate and resin.

5.  A major connector must not create food
entrapment areas. It should be self cleansing.
 The edges of the connector should be
rounded and tapered towards the tissues to
provide comfort.
 The borders should not cross bony or soft
tissue prominences.
 It should not interfere with phonetics.

6.  Single posterior palatal bar
 Palatal strap
 Anteroposterior, or double, palatal bar
 Horseshoe, or U-shaped connector
 Closed horseshoe, or anteroposterior palatal
strap
 Complete palate

7. 1. Since there is no movable tissue in the palate
as in floor of the mouth the borders of these
connectors may be placed well away (at least
6 mm) from the gingival margin.

8. 2. All components of a maxillary major
connector should cross the palate at right
angles. Curves in the connector should be
placed to one side of the midline.
Whenever possible, coverage of the
anterior palate should be avoided to
minimize interference with tongue function
and speech.

9. 3. The anterior borders of maxillary major
connectors should be hidden in a valley
between rugae so that the external surfaces of
the connectors are even or nearly even with
the crest of the tissue

12. 4. The borders of all maxillary major connectors
should be beaded (0.5 to 1.0 mm wide and
deep).
5. The bead is shallower over the midline suture
and fades out as it approaches within 6 mm of
the marginal gingiva. The bead maintains
positive contact with the soft tissues, increases
the rigidity of the connector.
6. Relief for maxillary major connectors is usually
provided only over tori and prominent midline
sutures

13.  Is narrow, half oval
with its thickest point
at the centre. The bar
is gently curved and
should not form a
sharp angle at the
juncture with the
denture base.

14.  ADVANTAGES
Only indication for the single posterior bar
is an interim partial denture.
Can be used in Kennedy class III
 DISADVANTAGES
One of the most difficult maxillary major
connectors for a patient to adjust to,
because to maintain any degree of rigidity
it has to be bulky. It should never be used
in a distal extension edentulous situation,
nor should it be used when anterior teeth
require replacement

15.  A palatal strap is a major connector used
primarily in tooth-supported (Kennedy Class
III) RPDs.
 The strap is generally as wide as the area
bounded by the four principal rests (minimum
width of 8 to 10 mm). Although the rigidity
provided by a palatal strap is not absolute, it
is usually adequate.

16.  Palatal strap is in three planes so it provides
great resistance to lateral or torsional forces.
 Greater rigidity
 Can be kept thin, so increase patient comfort
 Retention increased due to cohesion and
adhesion
 Provides some indirect retention

17. 1. Anterior border should be posterior to
rugae area.
2. Posterior border should terminate at the
junction of soft and hard palate.
3. Papillary hyperplasia

18.  Excellent rigidity
 Connector should not be used unless support
from remaining natural teeth
 Anterior bar should end in valleys between
rugae
 Posterior bar is half-oval, similar to single
posterior palatal bar connector
 The two bars are connected by flat
longitudinal on each side of lateral slopes of
the palate.

20.  Rigidity
 Palatal torus
 More patient comfort
Disadvantages
Little support is derived from bony palate

21.  The U-shaped connector often lacks
rigidity, particularly at the open
ends.
 Increasing tissue coverage and bulk
will improve rigidity but may
interfere with tongue function and
speech.
 A U-shaped connector is indicated
when a large, inoperable torus
extends posteriorly to within 6 to 8
mm or less of the junction of the
soft and hard palates or when the
patient cannot tolerate contact of
the prosthesis with the posterior
portion of the palate

22.  Indicated when several anterior teeth missing
 Can be indicated in torus
Disadvantages
Poor choice for distal extension as it tends to
flex when vertical forces applied

23.  The anterior-posterior (A-P) palatal strap is the
most versatile of all maxillary major connectors.
 It may be used for Kennedy Class I, II, III. or IV
partially edentulous arches. The thin straps
provide excellent rigidity and strength with
minimal tissue coverage and little interference
with tongue function.

24.  The anterior, posterior, and lateral straps
should be 6 to 8 mm wide.
 The lateral straps should be positioned
symmetrically, and the palatal border of the
straps should be located at the junction of the
vertical and horizontal portions of the palate
 The anterior strap must not be placed forward
of the most anterior rests, and the anterior
border should be located in a valley between
the rugae.
 The posterior border of the posterior strap
should be located at the junction of the hard
and soft palates

25.  For the palatal opening to be of significant
benefit, it should be 15 mm or more in
anteroposterior dimension. If the opening is
less than 15 mm, it would be better to use a
wide palatal strap or palatal plate.

26.  Types of anterior posterior palatal strap

27.  The palatal plate connector is primarily
indicated in Kennedy Class I arch forms where
only the anterior teeth (or anterior teeth plus
one or more premolars) remain, the support
from the residual ridge is poor, the abutments
are periodontally weakened, and/or adequate
direct retention is difficult to obtain.

28.  It cannot be used when a torus is present.
Because of the extensive soft tissue coverage,
the palatal plate may diminish taste perception,
interfere with tongue function, and be
uncomfortable to some patients. Its use should
be reserved for those cases where maximum
palatal coverage is necessary.

29.  Linguoplating may be used to provide
indirect retention or to allow for subsequent
replacement of natural teeth that have a
questionable prognosis. Linguoplating
should never be used indiscriminately,
however, and must always be accompanied
by adequate rest seats and rests.

30.  The palatal plate connector may be composed
entirely of metal or may be part metal and part
plastic. Plastic in the posterior portion allows for
postinsertion revision of the posterior palatal
bead and for relining/rebasing over residual
ridges that are still in the process of
recontouring

31.  A modified palatal plate is
a plate type connector
used in Kennedy Class II
RPDs.
 The anterior posterior
dimension of the plate
portion is generally
determined by the
location of the most
anterior and the most
posterior rests on the
tooth supported side
 Offers excellent rigidity
and good support

32. Blatterfein (1953) described a systemic
approach to designing maxillary major
connectors.
His methods involves five basic steps:
 Outline of primary bearing areas.
 Outline of non bearing areas
 Outline of connector areas
 Selection of connector type

34. 1. For maxillary major connector, relief is
A) Nor required b) always required c) both of
above d) None of the above
2. Beading is done under
a) Mandibular major connector
b) Maxillary major connector
c) Indirect retainer
d) Direct retainer

35. 3. Single posterior palatal bar is indicated in
a) Distal extension cases
b) In case of anterior teeth replacement
c) Interim dentures
d) None of above
4. Distance from gingival margin in maxillary
major connector
a) 4mm
b) 3mm
c) 6mm
d) 8mm

36. 5. Major connector should cross the gingival
margin
 A) 90 degree
 B) 45 degree
 C) 60 degree
 D) 30 degree
6. The minimum width of palatal strap should be
A) 6mm
B) 8mm
C) 10mm
D) 4mm

37.  Lingual bar connector
 Linguoplate (lingual plate) connector
 Double lingual bar (lingual bar and Kennedy
bar)
 Labial bar connector

38.  Relief is required between mandibular major
connector and soft tissue.
 For tooth supported RPD, minimum relief is
required while for distal extension more relief
is required.
 In addition to relief under lingual plate, relief
is required between gingival crevice and
metal.

39.  A lingual bar is the preferred mandibular major
connector except in the presence of a high
floor of the mouth, extreme lingual tilt of
anterior teeth, or inoperable lingual tori.

40.  Basic form of lingual bar is that of half-pear
shaped bar with the broadest portion at the
inferior border.
 Normal thickness is 6-gauge half pear
shaped
 At least 8mm of vertical space is required
with major connector height of 5mm and
3mm space between gingival margin and
superior border.

41.  In cross section, the lingual bar is half pear
shaped and at least 4 mm in height. The
superior border should be 3 to 4 mm below
the gingival margin.
 Thus, selection of a lingual bar as a major
connector requires a distance of 7 to 8 mm
from the gingival margin to the floor of the
mouth.

42.  Minimal relief is required
beneath a lingual bar if the
tissues exhibit a vertical
fall
 Relief must be increased if
the lingual tissues slope
more horizontally
 Only blockout (not relief)
is necessary if the lingual
tissue is undercut.

43.  Adequate relief beneath
the major connector
when the RPD is at rest
(R) prevents
impingement on the
lingual tissues during
function (F).
 Inadequate relief
beneath the major
connector when the RPD
is at rest (R) will result
in displacement of and
damage to the lingual
tissues during function
(F).

44.  Simplicity
 Minimum contact with tissues
 It doesn’t contact the teeth so no
decalcification
Disadvantages
It is less rigid

45.  A linguoplate connector consists of a lingual
bar plus a metal plate extending superiorly
above the cingula, but not higher than the
middle third of the teeth, The superior
border must be scalloped so that it extends
to the contacts inter proximally.

46.  A linguoplate is indicated in the presence of
a high lingual frenum or floor of the mouth
(or when the same effect is created by
extensive recession or periodontal surgery)
 in the presence of inoperable lingual tori;
 when the mandibular natural anterior teeth
may need to be replaced in the near future
or splinting is required.
 A linguoplate may also be necessary to
provide indirect retention when all of the
posterior teeth, are missing (rest seats and
rests must be provided at least on the
canines) or when the patient objects to a
lingual bar.

47.  If a linguoplate major
connector is selected.
The mesio and disto-
incisal corners of
overlapping anterior
teeth (A) should be
recontoured to
eliminate excessive
undercuts below the
contact points (B).
A linguoplate has the disadvantage of
covering the teeth and gingiva, thereby
complicating oral hygiene and increasing
the possibility of caries and periodontal
problems

48.  Adequate blockout and relief is provided for
both soft tissue undercuts and interproximal
region.
 Free gingival margin and sulcus area should
be relieved.
 Chrome is an excellent material for this type
of connector as it can be finished in thin
margins.
 It acts as indirect retention, must always be
supported by rests on each end od
edentulous span.

50.  The double lingual bar is composed of a
conventional lingual bar and a second narrower
bar located between the cingula inferiorly and
the contact points superiorly.

51.  The double lingual bar has been recommended
when indirect retention must be obtained from
the mandibular anterior teeth and large
interproximal spaces have resulted from peri-
odontal disease or surgery
 The upper border must clear the gingival margin
by 3 to 4 mm.
 Thus, the double lingual bar cannot be used as a
substitute for a conventional lingual bar when a
high floor of the mouth exists.
 The superior bar must have rests in prepared rest
seats at least on the canines

52.  The labial bar major connector is only selected
when no other major connector will suffice.
 It is indicated when the remaining natural teeth
are severely lingually inclined).
 Recontouring, orthodontic treatment, or
restoration with crowns may correct the problem,
but when such treatment is impossible or
impractical, the labial bar is a possible solution