Different designs of bridges

ByYasmin Mohammed

Group e2University of Baghdad/college of dentistry

Fixed partial denture •It is a fixed dental prosthesis which replace

and restore the function and esthetic of one or more missing natural teeth ,it can not be removed from the mouth by the patient. It is primarily supported by natural teeth or

root .

The bridge consists of :

1 .Retainer : it is the part of the bridge which is cemented to the abutment teeth .it could be full metal ,full veneer with facing , partial veneer , post crown or

inlay … etc.

2 .Pontic Is the part of the bridge which represent the missing tooth and it connected to the retainer by a connector

3 .Connector is the part of the bridge which connect the pontic and the retainer , it maybe rigid (solid joint ) or movable joint (precision attachment , key and key way )

Types of connectors •1 .rigid

•2 .non rigid •_tenon mortise conectors

•_loop connectors •_split pontic connectors

•_cross pin and wing connectors

Tenon mortise

Loop connectors split pontic

Cross pin and wing connectors

4 .Abutment Is the natural tooth which support the bridge and on which the retainer is cemented (tooth or root )

Crown_ root ratio •Is the measurement of the length of tooth occlusal to

the alveolar crest of the bone compare with the length of root embedded in the bone . The ideal crown root ratio for a tooth to be used as a bridge abutment is 1:2 , and the minimum ratio acceptable for prospective abutment under normal

circumstances is 1:1 .

Antews low •The root surface area (pericemental area

)of the abutment teeth should be more or at least equal to the root suface area (pericemental area )of the missing teeth

being replace .

Types of bridges •There are 4 main type of bridges

•1 .fixed _ fixed bridge •2 .fixed movable bridge

•3.cantilever bridge •4.resin bonded bridge (conservative bridge )

Fixed _fixed bridge •In this type the pontic is attached to the

retainers (mesial and distal)by rigid connector(solid joint) so they should have one path of insertion . This is the

most commonly used FPD.

Advantages: •1 .maximum retention and support.

•2 .abutment teeth are splinted together. 3 .the design is most practical for larger bridges.

disadvantages 1.require preparation to be parallel

2 .All the retainers are major retainers and require extensive ,destructive preparation of the abutment teeth.

3.Has to be cemented in one piece.

Fixed movable bridge •In this type the pontic is attached to one distal

major retainer (distal end of the pontic )by fixed connector while the other end is attached to the minor retainer (in front of pontic )by movable joint .it s indicated in case of drifted abutment teeth and difficulty to obtaining parallel

abutments .

Advantages :•1 .preparations do not need to be parallel to each other.

•2 .more conservative of tooth tissue because preparations for minor retainers are less destructive .

•3 .parts can be cemented separately. •Disadvantages

•1.more complicated to construct in laboratory than fixed fixed bridge.

•2.difficult to make temporary bridge.

Preoperative picture

Tooth preparation for porcelain fused to metal restorations

Case Prefabricated

castable bar attached

between waxed up copings

Metal try-in

Bar attached parallel to the ridge on palatal aspect

Waxed up trial denture for removable partial denture

Wax added on labial flange of removable partial denture for lip

support

Final cementation of porcelain fused to metal fixed partial denture and fixed component of Andrew's

Bridge

Andrews bridge placement