FIXED PROSTHODONTICS

TOPIC: INTRODUCTION TO FIXED PROSTHODONTICS

🎯 KEY POINTS:

🔹FPD replaces one or more teeth and is permanently cemented on the remaining teeth.

🔹Fixed dental prosthesis is also commonly referred to as fixed bridge.

🔹A retainer can be defined as a casting cemented to an abutment tooth which retains or helps to retain a pontic.

🔹Replacement tooth is called pontic. 

🔹If the pontic is supported only at one end, it is called cantilever pontic.

🔹Keyway of the connectors should be placed on the distal side of the pier abutment so that on mesial movement the key has a seating effect into the keyway.

🔹Pin pontic is also called interchangeable pontic.

🔹If keyway is placed on the mesial side of the pier abutment, it will have an unseating effect on mesial movement.

🔹If the tilted molar tooth is mesially and lingually inclined, then nonrigid connectors should be used.

🔹Sanitary or hygienic pontic is indicated in the posterior region of the lower jaw, as it provides good access for hygiene maintenance.

🔹Undersurface of the sanitary pontic is made round for easier flossing. This design is called fish belly.

🔹Modified design of sanitary pontic is concave archway mesiodistally. This design is called arc-fixed partial denture or Perel pontic.

🔹Modified ridge lap design is indicated in the high aesthetic zone in maxillary anteriors and bicuspid region.

🔹Ovate pontic provides superior aesthetic and is indicated in the maxillary anterior region and bicuspids.

🔹Conical or egg-shaped or bullet-shaped or heart-shaped pontic is

indicated in the non aesthetic zone, i.e. in cases of lower posterior region.

🔹Scalloped or trestle design of the connector is desired as the height of the metal strut is increased incisogingivally in order to enhance the strength.

🔹Recommended gap width between two surfaces to be soldered is 0.15 mm and optimum width should be 0.20 mm.

🔹Borates are used as soldering flux for noble metal alloys and fluorides are used as soldering flux for base metal alloys.

🔹The occlusal surface of the pontic should not be more than 85% of the occlusal surface of the tooth to be replaced.

🔹Brazing takes place when the melting temperature of the filler metal is greater than 450ºC.

🔹Extracoronal retainers sometimes referred to as major retainers.

🔹Soldered parts should not be quenched immediately, as this will produce thermal stresses, which lead to distortion.

🔹The intracoronal retainers are usually contraindicated in young adults because of high pulp horns.