conenctors in fpd

Conenctors In FPD

Deepak Kumar gupta

facebook.com/notesdental

The portion of a fixed partial denture that unites the retainer(s) and

pontic(s)


Classification

• Rigid connectors– Cast connector

– Soldered connector

– Loop connectors

• Non-rigid connectors– Tenon-Mortise connectors

– Split pontic connectors

– Cross pin and wing connectors

– Dove Tail


Ideal Requirements of connector

• Wide enough to provide strength to the unit, not wide enough to hamper the oral hygiene maintenance

• Occupy the normal interproximal areas –preserve the embrasure

• Placed lingually and incisally – esthetics

• Gap width of 0.25 mm


Rigid Connector

• Most commonly used, ideal for short span FDP

• It can be made by casting, soldering or welding– Casting : molten metal is casted in full unit die

including pontics and retainer

– Soldering : use of an intermediate metal alloy whose melting temperature is lower than that of the parent metal

– Welding : use of metal alloy having melting point as of parent alloy or joining by heat or pressure


Rigid Connectors

• Indication

– unite retainers and pontics in which entire load is directly transferred to the abutments

• Contraindication

– existing diastema is to be preserved

– Tilted abutment

– Long span bridge


Cast Connector• Shaped in wax as part of a

multiunit wax pattern• Convenient and minimize

the number of steps involved in the laboratory fabrication

• Pros : 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

• Not melted during soldering but must be thoroughly wettableby liquefied solder

• Dirt or surface oxides on the connector surfaces can reduce wetting and impede successful soldering


Soldered connectors

• waxed to final shape but are then sectioned with a thin ribbon saw

– surfaces to be joined are flat & parallel

– a controlled distance is maintained

• gap of about 0.25 mm is recommended


Loop connectors

• rarely used• Existing diastema is to be

maintained in a planned fixed prosthesis

• consists of a loop on the lingual aspect

• cast from sprue wax that is circular in cross-section or shaped from a platinumgold-palladium (Pt-Au-Pd) alloy wire


NON RIGID CONNECTORS: Indication

• when it is not possible to prepare two abutments for a partial FDP with a common path of placement – mesially tilted 2nd molars

• large, complex FDPs

• uncertainty about an abutment’s prognosis: in case of abutment failure - easier to replace or repair individually

• mandibular arch, consists of anterior and posterior segments

• mandibular opening and closing stroke - flexes mediolaterally

• Rigid FDP - inhibit mandibular flexure - dislodgment


NON RIGID CONNECTORS: Design• Consist of

– mortise(female): retainer• distal aspect

• Accurate alignment

• Dovetail or cylindrically shaped

• parallel to the path of placement of the distal retainer - dental surveyor

• prepared freehand in the wax pattern or with a precision milling machine or prefabricated plastic

– tennon (male): ponticsfacebook.com/notesdental

Soldering


Soldering

• It requires: Filler (Solder), Flux, Antiflux and heat source

• Flux– applied to a metal surface to remove oxides or

prevent their formation

– Gold alloys : borax glass (55 parts), boric acid (35 parts), and silica (10 parts)• powder, liquid, or paste form

– Base metal alloys : CrO is mainly formed, fluoride containing fluxes


Soldering• Antiflux

– limit the spreading of solder - flow into undesirable areas

– Graphite for low temp. or iron oxide (rouge) in a suitable solvent such as turpentine for high temp

• Heat Source• Torch Soldering: H2, Natural gas, propane, acetylene• Oven Soldering• Laser Soldering: Nd : YAG laser


Soldering


Soldering

Brazing: the filler - melting point above 450°C. used in dentistrySoldering: the filler - melting point below 450°C (842°F)


conenctors in fpd

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