Connectors –in fpd /certified fixed orthodontic courses by Indian dental academy

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INDIAN DENTAL ACADEMY
Leader in continuing dental education

 Connectors are those parts of a fixed

partial denture or splint that join the
individual Retainers and P
ontics
together.
 Usually this is accomplished with
-"Rigid connectors” although
nonrigid connectors are used
occasionally.
 T latter are usually indicated
he
when it is impossible to prepare a
common path of insertion for the
abutment preparations for an F D
P

CONNECTOR
T portion of an F D that unites the
he
P
retainer(s) and pontic(s).

RIGID CONNECTOR
A cast, soldered, or fused union between
the retainer(s) and pontic(s).

NON RIGID CONNECTOR
Any connector that permits limited
movement between otherwise
independent members of an F D.
P

RIGID CONNECTORS
Rigid connections in metal can be
made by casting, soldering, or
welding.

Cast connectors
 are shaped in wax as part of a

multiunit wax pattern.
Cast connectors are convenient and
minimize the number of steps

T
he fit of the individual

retainers may be
adversely affected
because distortion more
easily results when a
multiunit wax pattern is
removed from the die
system.

Soldered connectors
involve the use of an

intermediate metal alloy whose
melting temperature is lower than
that of the parent metal
T parts being joined are not
he
melted during soldering but must
be thoroughly wettable by
liquefied solder.

Dirt or surface oxides on

the connector surfaces can
reduce wetting and
impede successful
soldering; for example,
the solder may melt but
will not flow into the
soldering gap.

Welding

is another method of rigidly

joining metal parts.
H
ere the connection is created
by melting adjacent surfaces
with heat or pressure.
A filler metal whose melting
temperature is about the same
as that of the parent metal can
be used during welding.

 In industrial metalworking, a

distinction is made between soldering,
in which the filler metal has a melting
point below 450 º C (842º F and
),
brazing, in which the filler has a
melting point above 450 º C
 Rigid connections in dentistry are
generally fabricated above 450 º C,
but the process has almost always
been referred to in the dental literature
as soldering.
 A proposed international standard
uses the term brazing.

NONRIGID CONNECTORS
 Nonrigid connectors are indicated when it is

not possible to prepare two abutments for
an F D with a common path of placement.
P
 Segmenting the design of large, complex
F Ds into shorter components that are
P
easier to replace or repair individually is
advisable.
T
his can be helpful if there is uncertainty
about an abutment's prognosis.
 If the abutment fails, only a portion of the
F D may need to be remade.
P

 In the mandibular arch, nonrigid

connectors are indicated when a complex
F D consists of anterior and posterior
P
segments.
 During the mandibular opening and
closing stroke, the mandible flexes
mediolaterally.'
 Rigid fixed partial dentures have been
shown to inhibit mandibular flexure, and
extensive splints have been shown to
flex during forced opening
 T associated stresses can cause
he
dislodgment of complex F Ds.
P
 Segmenting complex mandibular F Ds
P

 Nonrigid connectors are generated

through incorporation of prefabricated
inserts in the wax pattern or through
customm
illing procedures after the first
casting has been obtained.
 The second part is then custom
-fitted to
the m
illed retainer and cast.
 Theyare often m
ade with prefabricated
plastic patterns.
 The retainers are then cast separately
and fitted to each other in m
etal.

CONNECTOR DESIGN

T size, shape, and position of
he

connectors all influence the success
of the prosthesis.
Connectors must be sufficiently
large to prevent distortion or
fracture during function but not too
large; otherwise, they will interfere
with effective plaque control and
contribute to periodontal
breakdown over time.

Adequate access (i.e., embrasure

space) must be available for oral
hygiene aids cervical to the connector
If a connector is too large
incisocervically, hygiene is impeded
and over time periodontal failure will
occur F esthetic F Ds, a large
or
P
connector or inappropriate shaping of
the individual retainers may result in
display of the metal connector.

TYPES OF CONNECTORS

RIGID CONNE ORS
CT
Rigid connectors must be
shaped and incorporated into
the wax pattern after the
individual retainers and
pontics have been completed
to final contour but before
reflowing of the margins for

Cast Connectors
Connectors to be cast are also waxed

on the master cast before reflowing
and investing of the pattern.
T presence of a cast connector
he
makes the pattern somewhat more
awkward.
Access to the proximal margin is
impeded, and the pattern cannot be
held proximally during removal from

Restricting cast connectors

to complete coverage
restorations is therefore
advisable, which can be
gripped buccolingually.
P
artial-coverage wax
patterns are easily distorted
when they are part of a
single-cast F D.
P

Soldered Connectors.
As with cast connectors,
connectors to be soldered are waxed
to final shape but are then sectioned
with a thin ribbon saw therefore,
when the components are cast, the
surfaces to be joined will be flat,
parallel, and a controlled distance
apart.

T allows accurate soldering
his
with a minimum of distortion.



M
olten solder will flow

toward the location where
the temperature is highest.
In metal, the two flat
surfaces previously created
in wax retain heat,
ensuring that the highest
temperature is in the

Soldering Gap Width.
As gap width increases,

soldering accuracy decreases .
E
xtremely small gap widths
can prevent proper solder flow
and lead to an incomplete or
weak joint.

An even soldering gap of

about 0.25 mm is
recommended.
If a connector area has an
uneven soldering gap width,
obtaining a connector of
adequate cross-sectional
dimension without resulting
distortion is more difficult

Loop Connectors

Although they are rarely used,

loop connectors are sometimes
required when an existing
diastema is to be maintained in a
planned fixed prosthesis.
T connector consists of a loop on
he
the lingual aspect of the prosthesis
that connects adjacent retainers
and/ pontics.
or

T loop may be cast from
he

sprue wax that is circular in
cross section or shaped from a
platinum-goldpalladium (P
tAu-P alloy wire.
d)
M
eticulous design is
important so that plaque
control will not be impeded

NON RIGID CONNECTORS
T design of nonrigid
he

connectors that are
incorporated in the wax
pattern stage consists of a
mortise (also referred to as the
female component) prepared
within the contours of the
retainer and a tenon (male)
attached to the pontic

T mortise is usually
he

placed on the distal aspect
of the anterior retainer.
Accurate alignment of the
dovetail or cylindrically
shaped mortise is critical; it
must parallel the path of
withdrawal of the distal
retainer

P
aralleling is normally

accomplished with a dental
surveyor.
W
hen aligning the cast, the
path of placement of the
retainer that will be
contiguous with the tenon is
identified.

T mortise in the other
he

retainer is then shaped so its
path of insertion permits
concurrent seating of the tenon
and its corresponding retainer.
 T mortise can be prepared
he
freehand in the wax pattern or
with a precision milling
machine.

Another approach is to

use prefabricated plastic
com
ponents for the m
orti
and tenon of a nonrigid
connector

As an alternative, a special

m
andrel can be em
bedded in
the wax pattern and the
abutm retainer can be cast,
ent
with refinem of the fem
ent
ale
com
ponent as necessary the
;
m keyis then fabricated of
ale
autopoly erizing acry resin
m
lic
and attached to the pontic.

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Connectors –in fpd /certified fixed orthodontic courses by Indian dental academy

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