Why are infrabulge clasps not recommended on the tooth-supported side?

Infrabulge clasps are not recommended for use on the tooth-supported side primarily because they engage undercuts that may be too close to a modification space. When a clasp is placed in this region, it can complicate the design of the partial denture by interfering with the placement of additional modifications, such as other prosthetic teeth.

If an infrabulge clasp is located near a modification space, it can limit the ability to add or adjust teeth in the future without compromising the stability and retention provided by the clasp. Maintaining clear separations between clasps and modification spaces is critical to ensure that the removable partial denture remains functional and aesthetically pleasing.

While considerations such as esthetics, fabrication challenges, and weight are certainly relevant in overall denture design, the specific issue of engaging undercuts close to modification spaces is crucial and emphasizes the need for strategic planning in the design of the RPD.