Fixed Partial Dentures are defined as “A partial denture which is cemented to natural teeth or roots which furnish the primary support to the prosthesis”. or “A restoration or replacement which is attached by cementing medium to natural teeth, roots, implants. In simple terms FPD’s are termed as crowns for the patient to better understand them. The primary function of an FPD is to cover, protect and restore the underlying tooth structure. A single crown is used to cover the extracoronal surface of a single tooth which is either Root Canal Treated or fractured or badly decayed. A Multi unit FPD is used to replace any missing teeth.
Fixed partial dentures are classified into types based on multiple factors such as abutments, length of the bridge, components used, etc. The criteria for classifying FPS’s are –
- The type of arch being considered should be visualized
- Differentiation between only tooth supported and tooth + tissue supported partial dentures should be done
- It should help in guiding the design of the FPD being constructed
- Should be widely accepted
The Fixed Partial Denture Classification is divided into three major classes which are divided into Divisions and then further divided into sub-divisions.
Classification of Fixed Partial Dentures:
FPD’s are majorly divided into three classes based on the location of the Edentulous space –
Class 1: Posterior edentulous spaces with either the Premolars of Molars missing
Class 2: Anterior edentulous spaces with either incisors or canines missing
Class 3: Antero-posterior edentulous spaces where teeth from the Anterior and Posterior arches are missing
Division of Fixed Partial Partial Dentures: Divisions give the information regarding the teeth adjacent to the edentulous space determining whether they are capable of giving support or not.
Division 1: Teeth present on only one side of the Edentulous space or teeth capable of taking support from only one side of the edentulous space – These type of FPD’s are called Cantilever FPDs.
Division 2: Abutments on both side of the Edentulos spaces are capable of taking the occlusal load as Conventional FPD.
Division 3: A single tooth is surrounded by edentulous space on either side and it is called as Pier Abutment.
Sub-divisions of FPD classification determines the status of the tooth which is taken as an abutment.
Sub-division 1: It is the Ideal type of Abutment with healthy teeth, which is capable of providing good support.
Sub-division 2: Tilted Abutments, in such cases the tilt of the abutment is adjusted or a modification in the desing of the FPD is done
Sub-division 3: Periodontally weak teeth which cannot take the weight of the occulsal load. These cannot take the occlusal load as effectively as healthy abutment and hence cannot be used as abutments.
Sub-division 4: Abutment tooth is either fractured or decayed but has good bone support. To use it as an abutment the tooth needs extensive restoration (inlay or onlay) to make it fit for an abutment crown.
Sub-division 5: Implant Abutment. An Implant is placed to act as an abutment in cases where the length of the birdge is more than what is termed ideal.
The Sub-divisions are further divided into A and B types.
Type A: The support for abutments is taken from a single tooth for one side of the edentulous space
Type B: The support for one side of the edentulous space is taken from more than one abutment tooth.
Now based on the classification it helps in visualizing the following by just using the classification – Location of edentulous space, occlusal load, design, status of the abutment tooth. So the classifications are given as – Class 1 Division 2, Sub-division 5-B.