The most common cause of failed extensive prosthetic reconstruction is incorrectly determined intermaxillary relations. The reference positions of the mandible are centric relation, physiological rest position and maximum intercuspidation. None of the known methods determining the vertical dimension of occlusion is completely reliable, and the most accurate value is obtained by combining them. Although changing the vertical dimension of occlusion is very often an integral part of prosthetic rehabilitation, some patients do not require it. Raising the vertical dimension should be carried out with patients who has: (1.) lowered vertical dimension, in which case we are talking about restoration; (2.) preserved vertical dimension where there is not enough space for prosthetic work, so we are talking about enlargement. Establishing the appropriate vertical dimension of occlusion is necessary for successful functional and aesthetic rehabilitation of the patient. Parafunctional movements can lead to hard dental tissues, but not necessarily to a lowering of the vertical dimension. When the bite collapses in the lateral segment and the vertical dimension is lost, aesthetic disharmony of the face, angular cheilitis, and a decrease in masticatory efficiency occur. Today, in case where it is not extreme and if prosthetic work covers a larger part of the dentition, it is considered that the increase in the vertical dimension of the occlusion does not necessarily lead to disturbances within the stomatognathis system due to adaption mechanisms. Although an increase in the vertical dimension of 5 mm is considered safe, there is a need to implement a minimal increase that positively affects function and aesthetics. If the signs and symptoms of the stomatognathic system occur, they usually stop within 2 weeks.