Planning a fixed bridge to replace tooth #30

Correct answer: B. Establishing a common path of insertion

• A. Mesial drift of #31 has REDUCED the space, but reduced space is a consequence of the drift; the governing prosthetic obstacle is the path of insertion.
• B. CORRECT. A fixed partial denture is a rigid, one-piece casting, so every retainer must draw along a SINGLE common path. When one abutment has drifted and rotated and the other has tipped, their long axes diverge and no single path exists without either over-preparing one abutment — risking pulp exposure — or accepting non-parallel preparations that will not seat.
• C. The stem states that both abutments are periodontally sound.
• D. Crown height is not identified as a problem here; both abutments are unrestored with normal clinical crowns.

Note: The realistic options: uprighting the abutments orthodontically first · a single implant, which sidesteps the parallelism problem entirely · or a non-rigid connector with a key-and-keyway allowing the retainers to seat along separate paths.

Correct answer: B. The sanitary (hygienic) pontic

• A. The ovate pontic sits within a surgically or provisionally developed concavity in the ridge and gives the best emergence profile. It is the aesthetic choice for ANTERIOR sites.
• B. CORRECT. The sanitary or hygienic pontic stands clear of the ridge, leaving a space of at least 2 mm beneath it for cleaning. That space is invisible and phonetically irrelevant in the mandibular posterior region, but in the maxilla it is visible and permits air escape that disturbs speech. It is therefore confined to non-aesthetic mandibular posterior sites.
• C. The modified ridge lap contacts only the BUCCAL aspect of the ridge, combining acceptable aesthetics with cleansability. It is the most widely used design.
• D. The conical pontic contacts the ridge at a single point and is used on thin, knife-edge mandibular posterior ridges.