A patient complains of cheek biting shortly after receiving new complete dentures. What is the most likely cause?

Cheek biting (morsicatio buccarum) in a new denture patient is most commonly caused by excessive vertical dimension of occlusion (VDO). When VDO is increased, the buccal corridor (space between the teeth and the cheek) is reduced, and the buccal mucosa is positioned in the occlusal plane where it can be accidentally bitten during chewing. Other causes include: denture teeth placed too far buccally (outside the neutral zone), insufficient freeway space, or poorly polished denture flanges. Management involves reducing the VDO, repositioning teeth within the neutral zone, or reducing overextended flanges.