Principles

Removable partial dentures (RPDs) are commonly prescribed as definitive appliances for the restoration of aesthetics and function (masticatory and phonetic), which may become compromised following the loss of teeth and the investing tissues, as well as for the preservation of occlusal stability. RPDs may sometimes be used in a transitional manner while carrying out stabilisation of oral disease or to enable the verification of planned occlusal changes, where there may be an occlusal anomaly such as the loss of occlusal vertical dimension.

RPDs can provide a minimally invasive and economic option for the replacement of multiple missing teeth (and supporting tissues), especially where there may be more than one edentulous space, while also concomitantly offering the benefit of lip and cheek support. They also give the potential for contingency planning when the residual dentition presents with a guarded prognosis.

However, by virtue of not being ‘fixed’ prostheses, they may not offer the same level of masticatory function or feeling of self-confidence as is optimally desired. Furthermore, there is the potential for the exacerbation of oral disease (in the presence of a removable appliance) in an unfavourable environment. The latter can, however, be further controlled by paying careful attention to appliance design and the implementation of an effective preventative regime.¹, ²

It is important that the planning and design of RPDs are primarily viewed as the role and responsibility of the dental practitioner, and are undertaken as part of whole patient care and overall restorative planning. This chapter will outline the stages in RPD design. The appropriate use of a design sheet is advisable.

Procedures

Following a comprehensive patient assessment (including a detailed evaluation of the edentulous spaces, any existing appliances, potential abutment teeth and the prognostic outcome of the residual dentition), it is worth fabricating a set of accurate study casts, which may require mounting on a suitable form of dental articulator.

It is important also to identify the presence of any features that may reduce the intra- or interocclusal spaces, such as tilted, rotated, drifted and over-erupted teeth as well as any hard or soft tissue factors that may compromise the insertion of an RPD. A detailed static and dynamic occlusal assessment should be carried out, additionally noting the freeway space (FWS), the presence of any occlusal interferences and/or any slides between the intercuspal position (ICP) and the first point of tooth contact in centric relation (CRCP). Aspects that may compromise the provision of an RPD or its ability to restore aesthetics and function should be identified and managed at this stage.

Having determined the edentulous spaces that are to be replaced by the RPD, commence with the selection of an appropriate path of insertion (and withdrawal) or POI using a dental surveyor (as seen in Figure 8.1.1). The selection of a POI will be influenced by a number of factors: