different designs of dental bridges
TRANSCRIPT
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