An effect of dental edges to the speech production―Speech analysis before/after the treatments

In this paper, we present an effect of dental edge treatments to speech articulation. Although it is not commonly known, the dental industry has reported that adjusting the occlusion (bite alignment) can lead to clearer speech and improvements in symptoms such as stiff shoulders. We recorded various styles of speech before and after occlusal adjustment for about 150 patients and statistically analyzed the treatment effects using two-dimensional Gaussian distributions of formants for five Japanese vowels, as well as measures of vowel variability and direction of vowel movement. We also focused on consonantal sounds and examined their changes in detail, such as Japanese syllables ra and voiceless alveolar fricatives in the sa-row, using both objective measures from waveform analysis and subjective assessments. The results suggest that occlusal treatment influences tongue movement even for the consonants, indicating improved articulation in many of the patients.