© Springer-Verlag 2007
Patients with temporomandibular dysfunction (TMD) require correction of mandibular position, but the ideal position for the mandible remains controversial. Miralles et al.  found the amount of freeway space (FS) required depended on the protocol used to measure it. For example, a significantly higher clinical FS value was found using a phonetic method than after swallowing or with the mandible in a relaxed postural position. A sibilant is the hissing or whistling sound heard in the formation of certain letters in speech, such as the letter “s.” A phoneme is the smallest unit of speech that defines one sound from another.
Thus, a sibilant phoneme registration (SPR) protocol is colloquially known as a ‘phonetic bite’. Patients with TMD secondary to temporomandibular joint (TMJ) inflammation (retrodiscitis), disc displacement, or disc dislocation require an antero-posterior (AP) correction inter alia.