Which phonetic sound is most important for evaluating the physiologic REST POSITION of the mandible in complete denture patients?

The 'M' sound (humming phoneme) causes the mandible to assume its natural physiologic rest position. When the patient says or hums 'Mmm,' the mandible relaxes to rest position. The distance between the denture teeth at rest (rest vertical dimension) minus the occlusal vertical dimension (OVD) equals the freeway space (normal = 2-4 mm). If the freeway space is inadequate, the VDO is too high; if excessive, VDO is too low. The 'F' and 'V' sounds evaluate the maxillary anterior tooth length and position (lower vermillion border of upper lip contacts incisal edges of upper centrals during 'F'). The 'S' sound evaluates the closest speaking space (~1 mm). For INBDE: 'M' = rest position; 'S' = speaking space; 'F/V' = anterior tooth position.