Evaluation of the closest speaking space in different dental and skeletal occlusions

Abstract

Statement of problem: The closest speaking space (CSS) together with the vertical overlap of anterior teeth during the production of the /s/ sound have not been previously investigated with respect to differences in dental and skeletal orthodontic classifications.

Purpose: The purpose of this study was to investigate the CSS in dental and skeletal occlusions and to analyze the cause and effect relationship of the CSS and the amount of the vertical overlap of anterior teeth.

Material and methods: Poly vinylsiloxane interocclusal registration material was placed bilaterally onto the occlusal surfaces of premolar and molar teeth of 155 native Turkish speaking adolescent and young adult dentate participants, who were then asked to pronounce the word seyis. The thinnest point between the maxillary and mandibular teeth was recorded in millimeters as the CSS. The occlusion of each participant was classified according to the Angle dental and Steiner skeletal classifications. The differences in CSS values within each classification were statistically analyzed with the Kruskal-Wallis test, and the correlation between the CSS and the vertical overlap was statistically analyzed with the Spearman Rho Correlation tests (P<.05).

Results: The differences in the CSS were only significant between Angle Class II division 2 and Class III groups (P=.034), while the differences in the CSS between skeletal classes were not significant. The correlation between the amount of CSS and the amount of vertical overlap was not significant.

Conclusions: The results showed that regardless of dental and skeletal occlusions, average CSS values could be used to determine the occlusal vertical dimension of prosthetic restorations.