Clinical rest and closest speech positions in the determination of occlusal vertical dimension

Abstract

Two subject groups had their mandibular positions determined, using an electrognathograph, at the clinical rest position (CRP) and at the closest speaking position (CSP). They were classified into a toothwear (largely of attritional origin) group (n=30) and a non-toothwear, or normal, group (n=60). The mean CRP deduced for the groups was similar in all three dimensions and found to be just less than 2 mm open from and 0.6 mm posterior to intercuspal position (IP) and approximately in the midline. The CSP, in two dimensions, of the toothwear group was significantly closer to IP than that of the normal group. The vertical component of CRP and CSP was similar for the normal group but CSP was significantly reduced in comparison to CRP for the toothwear group. The most forward component of CSP was significantly more anteriorly placed than was that of CRP. Although there was a pronounced inter-individual variation the results suggest toothwear, of long acting aetiology, has less affect on CRP than on CSP.

Relation between speaking space of the /s/ sound and freeway space in dentate and edentate subjects

“…It was stated that the closest speaking space is greater than the FS in dentate subjects 10,14 . Similarities between SSS and FS were shown in several studies 3,8,12,21 . However, no previous report showed that the FS was greater than the SSS.…”

“…Functional adaptation was also shown for a group of subjects with severe toothwear. A cross-sectional study found that the closest speaking space in this group was reduced in comparison with that in a control group 3 . In other words, this reflects an adaptation to a slowly modified incisal relationship.…”

“…Thus, it is proposed that assessment of resting and speaking positions does not provide a reliable guide to accurate approximation of original OVD 3 . Adaptation to a new OVD could alter both the resting position and the mandibular position needed to say the /s/ sound.…”

Interocclusal Clearance during Speech and in Mandibular Rest Position

“…However, as other studies reported broad variations in the values registered in one and the same individual by the different methods [10,29,35], none of the methods could be given preference to date [11,43]. Other authors showed that the mandibular position while speaking specific consonants (speaking space) approximates the rest position very closely and is more readily reproducible [6,7,25,42].…”

Occlusale verticale dimensie bij volledige gebitsprothesen

“…De geringste interocclusale spraakafstand bleek echter meer te variëren dan de fysiologische rustpositie. Burnett (2000) toonde aan dat bij patiënten met occlusale gebitsslijtage de geringste interocclusale spraakafstand kleiner was dan bij patiënten zonder gebitsslijtage, vermoedelijk doordat patiënten neuromusculair adapteren aan de ontstane situatie. Het gebruiken van de s-klanken voor het bepalen van de occlusale verticale dimensie bleek dan ook minder betrouwbaar dan voorheen werd aangenomen (Rivera-Morales en Goldman, 1997).…”