2004 Fiscal Year Final Research Report Summary
Relationship between the developmental variation in tongue function with open-bite and the articulatory disorder
| Project/Area Number |
14370689
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
矯正・小児・社会系歯学
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
ISHIKAWA Masaaki Tokyo Medical and Dental University, School of Dentistry, Professor, 歯学部, 教授 (40114730)
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| Co-Investigator(Kenkyū-buntansha) |
MIWA Zenzo Tokyo Medical and Dental University, Dental Hospital, Assistant Professor, 歯学部附属病院, 講師 (30157705)
MUKAI Yoshiharu Showa University, School of Dentistry, Professor, 歯学部, 教授 (50110721)
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| Project Period (FY) |
2002 – 2004
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| Keywords | Open-bite / Tongue thrust / Acoustic analysis / Articulatory disorder / Formant frequency / Ultra-sonography / Rest position of tongue / Posture of tongue dorsum |
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| Research Abstract |
This study intended to develop the oral function of children who had the problem in tongue posture with anterior open bite by clarifying both their tongue positions and the articulation characteristics. Each examinee was asked to say the short sentence "Hana ga Saita", and all the recorded sound was compared between open bite and normal bite children using the acoustic analysis of speech. The whole sound-waveform was expressed by both the sound-spectrogram and the formant history. The formant frequencies (F1, F2, F4) of voiceless alveolar fricative sound /s/ were extracted. As F4 is supposed to reflect the length of a talker's vocal tract, both F1 and F2 were divided by F4 in order to evaluate them relatively. The frequencies of F1 and F2 in patients with open bite were significantly higher than those in patients with normal bite. It is suggested that in patients with open bite the alveolar became an interdental, the fricative became an approximant.
Tongue postures were analyzed by the ultra-sonography. First, normal developmental process in the central groove formation on tongue dorsum was observed at oral swallowing stage. 20 females were divided into four groups according to their dental stages, their tongue movement at the line connecting the left and right upper first molars while drinking water was observed by B+M Mode. The results suggested that the time at when the central groove formation became mature was the early mixed dentition period. Furthermore, to find the characteristics of the tongue posture in rest position among different occlusal groups, B Mode sagittal images of the tongue dorsum were analyzed. The correlation between the curvature of tongue dorsum (CTD) and the over-bite was discussed. The results showed that the tongue posture in rest position influenced the anterior incisor relationship and the tongue dorsum of open bite children was relatively flat.
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