Reduced interocclusal distance in complete dentures results in limited vertical space for denture base thickness and occlusal surfaces. This restriction compromises the mechanical advantage of the jaws during mastication, leading to a decrease in biting force. Additionally, insufficient interocclusal distance can cause premature occlusal contact, further reducing effective force generation. Hence, a proper vertical dimension is critical to maintaining optimal masticatory efficiency in denture wearers.

Reference: Contemporary Fixed Prosthodontics, Rosenstiel, Edition 5.