A patient with poor oral hygiene wears an acrylic removable partial denture and presents with vertical bone loss on two molars. What is the most likely cause?

Correct answer: D. Plaque accumulation around the prosthesis combined with occlusal trauma from the appliance

• A. Clasp position matters — a poorly designed or unsupported clasp transmits torque — but it is not sufficient on its own. Without plaque there is no bone loss, however the wire is placed.
• B. Physiological remodelling does not create angular defects around specific teeth.
• C. Acrylic allergy is rare and presents as diffuse mucosal erythema and burning in the tissue contacting the denture, not as localised vertical bone loss.
• D. CORRECT. Vertical (angular) bone defects require BOTH a bacterial insult and a modifying factor. An acrylic partial denture with poor hygiene traps plaque against the abutment teeth and the gingival margin, driving the inflammatory bone loss; the appliance simultaneously transmits OCCLUSAL and lateral forces to those abutments, and trauma from occlusion converts what would be horizontal bone loss into an angular pattern. Neither factor alone would produce this picture.

Note: Remember the principle: occlusal trauma alone does NOT cause attachment loss. It acts as a co-destructive factor that modifies the pattern of plaque-induced bone loss.