Explanation: Polyurethane resilient liners do require special processing equipment for their fabrication. This can be a disadvantage in comparison to other types of liners that may be easier to produce and handle in a typical dental setting.

The mean denture bearing area in the edentulous mandible is approximately 12.25 cm square.

Explanation: Increasing the VDO can lead to increased vertical clearance between the teeth, potentially causing them to click during function. This can also affect the patient's speech and the stability of the denture. It is important to carefully evaluate and adjust the VDO to minimize these issues.

While guiding planes are the primary elements that dictate the path of insertion and removal, the minor connector also plays a role. The minor connector helps in the overall stability and retention of the RPD by linking the major connector to the abutment tooth and distributing the forces more evenly across the denture base. However, its primary function is not to guide the path of insertion and removal as much as it is to provide additional support and strength to the RPD.

Of the four factors affecting balanced occlusion in complete dentures, which of the following can be altered by only a slight amount: incisal guidance.