fixed versus removable

FIXED VERSUS REMOVABLE PARTIAL DENTURE(comparison in preference)

DEFINITION
Removable partial denture:------------------------------------------------------------------------------------------------. Fixed partial denture:-----------------------------------------------------------------------------------------------------------.

Although replacement of missing teeth by means of fixed partial dentures, either tooth - or implant-supported, is generally the method of choice, there are many reasons why a removable partial denture is the best method of treatment for a specific patient. Ultimately, the choice of treatment must meet the economic limitations and personal desires of the patient.(limitation factor)

INDICATIONS FOR REMOVABLE PARTIAL DENTURE

Whenever possible edentulous spaces should be restored with FPD rather than RPD, however under the following circumstances RPD is preferable:
1- Where vertical support from the edentulous ridge is needed . e.g. in the absence of a distal abutment.


Replacement of missing posterior teeth is often best accomplished with a removable partial denture, especially when implant treatment is not feasible for the patient. The exception to this includes situations in which the replacement of missing second (and third) molars is either inadvisable or unnecessary ,here unilateral replacement of a missing first molar can be accomplished by means of a multiple -abutment cantilevered fixed restoration or an implant-supported prosthesis.

e.g. to ensure stability with a long edentulous space

2-Where resistance to lateral movement is needed from contra-lateral teeth and soft tissues.



in the absence of cross-arch stabilization, the torque and leverage would be excessive on the two abutment teeth. Instead, a removable denture that derives retention, support, and stabilization from abutment teeth on the opposite side of the arch is indicated as the logical means of replacing the missing teeth.

3-Inadequate periodontal support The abutment teeth that exhibit reduced periodontal support because of periodontal disease that would benefit from cross-arch stabilization.

4- considerable bone loss in the visible anterior region.

A removable partial denture will permit the location of the replaced teeth in a favorable relation to the lip and opposing dentition regardless of the shape of the residual ridge. When such a removable prosthesis is made, however, positive support must be obtained from the adjacent abutments.


The pontic of a fixed partial denture must be correctly related to the residual ridge and in such a manner that the contact with the mucosa is minimal Whenever excessive resorption has occurred, teeth supported by a denture base may be arranged in a more acceptable buccolingual position than is possible with a fixed partial denture. Unlike a fixed partial denture, the artificial teeth supported by a denture base can be located without regard to the crest of the residual ridge and more nearly in the position of the natural dentition for normal tongue and cheek contacts. This is particularly true of a maxillary denture.


Tissue changes are inevitable following extractions. The replacement of teeth after recent extractions often cannot be accomplished satisfactorily with a fixed restoration. When relining will be required later or when a fixed restoration using natural teeth or implants will be constructed later, a temporary removable partial denture can be used .
5-After recent extractions


6- Unusually Sound Abutment Teeth Sometimes the reasoning for making a removable restoration is the desire to see sound teeth preserved in their natural state and not prepared for restorations.


If the prognosis of an abutment tooth is questionable, or if it becomes unfavorable during treatment, it might be possible to compensate for its loss by a change in denture design,or the removable partial denture can be remade(transitional denture).
7- Abutments with questionable prognosis



8-Alteration of vertical dimension Vertical dimension has to be altered gradually. The required change has to be accomplished in two or three increments. So this is better accomplished by making a removable prosthesis giving the necessary time to the patient to adjust to each increment.

PREFERANCE OF FIXED RESTORATIONS:

1-Tooth-Bounded Edentulous Regions
any unilateral edentulous space bounded by teeth suitable for use as abutments should be restored with a fixed partial denture cemented to one or more abutment teeth at either end. The length of the span and the periodontal support of the abutment teeth will determine the required number of abutments.


unilateral tooth loss is sometimes inappropriately treated by removable partial denture . This type of prosthesis does not benefit from: 1-cross- arch stabilization 2-places excessive stress on abutment teeth. 3- Possibly more importantly, there is a Significant risk for aspiration if such a prosthesis is dislodged during use.

2-Anterior modification spaces

Usually, any missing anterior teeth in a partially edentulous arch, are best replaced by means of a fixed restoration.There are exceptions: .Kennedy Class IV arch , Sometimes a better esthetic result is obtainable when the anterior replacements are supplied by the removable partial denture. . treatment is simplified by inclusion of an anterior modification space into the removable partial denture. . excessive tissue and bone resorption necessitates the placement of the pontics in a fixed partial denture too far palataly for good esthetics or for an acceptable relation with the opposing teeth.

3-Replacement of unilaterally missing molars (shortened dental arch)

To restore the missing molars with a fixed partial denture would require a cantilever prosthesis or the use of dental implants. A cantilever fixed prosthesis is most applicable if the second molar is to be ignored.


then only first molar occlusion need be replaced by using a cantilever-type fixed partial denture. The cantilevered pontic should be narrow buccolingually and not occlude with more than one half to two thirds of the opposing tooth. Often, such a restoration is the preferred method of treatment. However, at least two abutments should be used to support a cantilevered molar opposed by a natural molar Unilaterally missing molars. If the patient exhibits opposing contacts to the remaining 6 posterior teeth (bilateral premolars, right first and second molars), there may be minimal functional gain from replacing the left molars., By contrast, the functional gain from replacement of the posterior occlusion in this patient is likely significant.



To replace unilaterally missing molars with a removable partial denture necessitates use of a distal extension prosthesis. This involves the major connector joining the edentulous side to retentive and stabilizing components located on the non-edentulous side of the arch. Leverage factors are frequently unfavorable, and the retainers used on the Non-edentulous side are often unsatisfactory. factors important to consider in making the decision to provide a unilateral , distal extension removable partial denture include the opposing teeth and the future effect of the maxillary tuberosity

Second the future effect of a maxillary tuberosity must be considered if concern exists for tuberosity enlargement. Often when left uncovered, the tuberosity increases in size, making future occlusal treatment difficult. However, covering the tuberosity with a removable partial denture base, in combination with the stimulating effect of the intermittent occlusion, helps mantain tuberosity size and position. In such an instance, it may be better to make a removable partial denture with cross-arch stabilization and retention .
First the opposing teeth must be considered if it is considered important to prevent extrusion and migration. This influences the replacement of the missing molars far more than any improvement in masticating efficiency that might result

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