Are speech-based techniques for determination of occlusal vertical dimension reliable?

This article describes the most common techniques used for clinical assessment of occlusal vertical dimension (OVD), and includes a discussion of recently published data which strongly suggest that techniques based on sibilant sounds are not as reliable as they are generally regarded to be for the evaluation of OVD. Assessment and establishment of OVD are sometimes difficult in edentulous patients, as well as for dentate patients with multiple missing posterior teeth and/or extensive wear. Techniques based on the use of interocclusal distance and facial soft-tissue contours, along with techniques based on sibilant sounds, are discussed. Although absolute scientific support for any technique is lacking, the careful use of the techniques described in this article, in combination, will usually result in the establishment of a clinically acceptable OVD for most patients.