Which pontic design in a fixed partial denture is the most difficult for the patient to clean and maintain?

The full ridge lap (saddle) pontic wraps around both the buccal and lingual aspects of the residual alveolar ridge, creating contact with the ridge on both sides. This concave design traps food debris, plaque, and bacteria, making it virtually impossible for patients to clean adequately. It is contraindicated due to its association with ridge tissue inflammation and destruction. In contrast: the sanitary (hygienic) pontic has a convex surface with complete clearance of the ridge and is the easiest to clean (but least esthetic); the modified ridge lap contacts only the buccal ridge surface; the ovate pontic has a convex tissue surface that fits into a surgically prepared socket site and is the most esthetic while being moderately cleanable.