When designing a complete denture, the artificial posterior teeth should be positioned over the crest of the residual ridge primarily to:

Placing posterior teeth over the ridge crest directs masticatory load down the long axis of the ridge, minimizing tipping and rocking forces and improving stability and support. Teeth set buccal or lingual to the crest create leverage that unseats the denture.Other options: Esthetics is driven mainly by anterior tooth position; tooth position does not set the VDO; the number of teeth is a separate decision.Key exam takeaway: Set posterior teeth over the ridge crest to keep forces axial and the denture stable.