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Inamochi Y, Fueki K, Usui N, Taira M, Wakabayashi N. Adaptive brain activity changes during tongue movement with palatal coverage from fMRI data. Sci Rep 2021; 11:13907. [PMID: 34230552 PMCID: PMC8260614 DOI: 10.1038/s41598-021-93332-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 06/23/2021] [Indexed: 11/09/2022] Open
Abstract
Successful adaptation to wearing dentures with palatal coverage may be associated with cortical activity changes related to tongue motor control. The purpose was to investigate the brain activity changes during tongue movement in response to a new oral environment. Twenty-eight fully dentate subjects (mean age: 28.6-years-old) who had no experience with removable dentures wore experimental palatal plates for 7 days. We measured tongue motor dexterity, difficulty with tongue movement, and brain activity using functional magnetic resonance imaging during tongue movement at pre-insertion (Day 0), as well as immediately (Day 1), 3 days (Day 3), and 7 days (Day 7) post-insertion. Difficulty with tongue movement was significantly higher on Day 1 than on Days 0, 3, and 7. In the subtraction analysis of brain activity across each day, activations in the angular gyrus and right precuneus on Day 1 were significantly higher than on Day 7. Tongue motor impairment induced activation of the angular gyrus, which was associated with monitoring of the tongue's spatial information, as well as the activation of the precuneus, which was associated with constructing the tongue motor imagery. As the tongue regained the smoothness in its motor functions, the activation of the angular gyrus and precuneus decreased.
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Affiliation(s)
- Yuka Inamochi
- Removable Partial Prosthodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Kenji Fueki
- Removable Partial Prosthodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
| | - Nobuo Usui
- Biointerfaces Unit, Institute of Innovative Research, Tokyo Institute of Technology, S3-12 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Masato Taira
- Department of Cognitive Neurobiology, The Center for Brain Integration Research, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Noriyuki Wakabayashi
- Removable Partial Prosthodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
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Ozawa E, Honda EI, Tomizato H, Kurabayashi T, Nunthayanon K, Ohmori H, Shimazaki K, Ono T. Preliminary study of articulatory characteristics in open bite subjects revealed by 3T magnetic resonance imaging movies. APOS TRENDS IN ORTHODONTICS 2021. [DOI: 10.25259/apos_174_2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Objectives:
Previous studies have reported that articulatory dysfunction accompanied by a certain type of malocclusion can be improved by orthodontic treatment. We developed a 3-T magnetic resonance imaging (MRI) movie method with tooth visualization that can display the dynamic movement of articulation without radiation exposure. To the best of our knowledge, there is currently no report on the possible differences in articulatory movement between subjects with a normal occlusion and those with malocclusion using the 3T MRI movie method. Thus, the objective of this study was to examine the articulatory difference between subjects with a normal occlusion and those with an open bite using an MRI movie.
Materials and Methods:
Twenty healthy adult females, ten with a normal occlusion and ten with an anterior open bite were recruited. The overbite of the open bite subjects was zero or smaller, and all of them exhibited a tongue-thrusting habit during swallowing. A turbo spin echo image with a contrast medium was used to visualize the anterior teeth, and articulatory movement during articulation of the vowel-consonant-vowel syllable (/asa/) was scanned. The difference in tongue movement between subjects with a normal occlusion and those with an open bite was compared by measuring seven variables. Moreover, the distance between the incisal edge and the tongue apex during articulation of /s/ and the speech duration were compared. Furthermore, frequency analysis on /s/ by fast Fourier transform power spectrum was performed.
Results:
The tongue apex of the open bite subjects moved more anteriorly than that of the normal subjects. However, there was no significant difference in the phonetic analysis between subjects with a normal occlusion and those with an open bite.
Conclusion:
The 3-T MRI movie was an efficient method to quantify articulatory tongue movements. Although there was a difference in tongue movement during swallowing between subjects with a normal occlusion and those with an open bite, the difference in the articulatory tongue movements was minimal, suggesting it could be a functional compensation.
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Affiliation(s)
- Erika Ozawa
- Department of Orthodontic Science, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Ei-ichi Honda
- Department of Oral and Maxillofacial Radiology, University of Tokushima, Tokushima-shi, Tokushima-kenn, Japan
| | - Hiroshi Tomizato
- Department of Oral and Maxillofacial Radiology, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan,
| | - Tohru Kurabayashi
- Department of Oral and Maxillofacial Radiology, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan,
| | - Kulthida Nunthayanon
- Department of Preventive Dentistry, Orthodontic Division, Naresuan University, Mueang Phitsanulok, Thailand,
| | - Hiroko Ohmori
- Department of Orthodontic Science, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Kazuo Shimazaki
- Department of Orthodontic Science, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Takashi Ono
- Department of Orthodontic Science, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
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Ekprachayakoon I, Miyamoto JJ, Inoue-Arai MS, Honda EI, Takada JI, Kurabayashi T, Moriyama K. New application of dynamic magnetic resonance imaging for the assessment of deglutitive tongue movement. Prog Orthod 2018; 19:45. [PMID: 30417234 PMCID: PMC6230546 DOI: 10.1186/s40510-018-0245-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 10/10/2018] [Indexed: 01/26/2023] Open
Abstract
Background Deglutitive motion of the tongue may function to maintain tooth position. However, the causation between abnormal patterns of orofacial muscle function and dental malocclusion remains unclear. To clarify the pathogenic mechanism of malocclusion, it is important to determine the relative positional relationship between the tongue tip and incisor edge or the dorsal tongue and palate during deglutition. Here, we assessed the utility of 3-T segmented cine-magnetic resonance (MR) imaging, combined with static MR images for hard tissue visualization, in assessing the relationship between the tongue and the surrounding tissues during deglutitive tongue movement. Methods Cine-MR images were acquired from three healthy female volunteers during deglutition who had no history of swallowing disorder or other chronic illness, normal alignment and occlusion, and a skeletal class I relationship. Three cine-MR images were taken during deglutition in accordance with an auditory cue for each volunteer. During static imaging, custom-made, contrast-medium-filled clear retainers were positioned in the mouth to allow visualization of the upper and lower incisors and hard palate boundaries. Static images were superimposed onto images of the three stages in deglutitive tongue movement, which were selected from a series of cine-MR images. These superimpositions were assessed five times by tracing cephalometric parameters to examine the reproducibility of the method. Results Traces varied little across repeated measurements, and all subjects had a similar pattern of dorsal tongue movement. Tongue-to-palate contact increased slightly during the first to second stage of swallowing and abruptly increased during the second to third stage, while the tongue tip position remained constant. Conclusions Segmented cine-MR imaging combined with static MR images is useful for assessing soft tissue motion during deglutition. This method is particularly useful in dentistry to evaluate the relationship between tongue function and maxillofacial morphology in terms of orthodontic treatment and orofacial myofunctional therapy, and for improving tongue movement during speech therapy. Electronic supplementary material The online version of this article (10.1186/s40510-018-0245-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Issareeya Ekprachayakoon
- Maxillofacial Orthognathics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.,Chulalongkorn University-Tokyo Medical and Dental University Research and Education Collaboration Center, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Jun J Miyamoto
- Maxillofacial Orthognathics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
| | - Maristela Sayuri Inoue-Arai
- Maxillofacial Orthognathics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Ei-Ichi Honda
- Oral and Maxillofacial Radiology, Tokushima University Graduate School, 3-17-15, Kuramoto-cho, Tokushima, 770-8504, Japan.,Oral and Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Jun-Ichi Takada
- Maxillofacial Orthognathics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Tohru Kurabayashi
- Oral and Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Keiji Moriyama
- Maxillofacial Orthognathics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
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Principles of the magnetic resonance imaging movie method for articulatory movement. Oral Radiol 2018; 35:91-100. [DOI: 10.1007/s11282-018-0347-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/21/2018] [Indexed: 11/25/2022]
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Ozawa E, Honda EI, Parakonthun KN, Ohmori H, Shimazaki K, Kurabayashi T, Ono T. Influence of orthodontic appliance-derived artifacts on 3-T MRI movies. Prog Orthod 2018; 19:7. [PMID: 29457192 PMCID: PMC5817053 DOI: 10.1186/s40510-018-0204-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 01/15/2018] [Indexed: 11/22/2022] Open
Abstract
Background Magnetic resonance imaging (MRI) has been used to study configurations of speech organs in the resting state. However, MRI is sensitive to metals, and numerous types of metallic appliances, most of which have a large magnetic susceptibility, are used in orthodontic treatment and may cause severe artifacts on MRI. We have developed techniques for obtaining MRI movies of the oral region, to evaluate articulatory changes, especially movement of the tongue, palate, and teeth, pre- and post-orthodontic/orthognathic treatment. We evaluated the influence of artifacts caused by orthodontic appliances, including fixed retainers, metal brackets, and wires, on measurements in 3-T MRI movies. Methods Sixteen healthy young adults (nine males, seven females; average age, 27 years) with normal occlusion were recruited. Four types of customized maxillary and mandibular plates were prepared by incorporating one of the following into the plate: (a) nothing, (b) a fixed canine-to-canine retainer, (c) metal brackets for the anterior and molar teeth, or (d) clear brackets for the anterior teeth and metal brackets for molars. A 3-T MRI movie, in segmented cine mode, was generated for each plate condition while participants pronounced a vowel-consonant-vowel syllable (/asa/). The size of the artifact due to the metallic brackets was measured. The face size and orthodontically important anatomical structures, such as the velum, the hard palate, and the laryngeal ventricle, were also measured. Results A large artifact was observed over the entire oral region around orthodontic appliances, altering regional visibility. The velopharyngeal height was measured as significantly longer in the presence of metal brackets. The maximum artifact size due to a metallic bracket was > 8 cm. Our results show that even if it is possible to obtain the measurements of palate length, nasion to sella, and nasion to basion in individuals wearing metal brackets for molars, the measurements might be affected due to the presence of artifacts. Conclusions Orthodontic appliances, including metallic materials, sometimes produce significant measurement error in speech evaluation using MRI movies, which often become invisible or distorted by metallic orthodontic appliances. When the distorted image is measured, caution should be exercised, as the measurement may be affected. Based on the study, it is concluded that orthodontists should not necessarily remove all metallic appliances before MRI examination because the influence varies among the appliances and should also know that a significant measurement error in speech evaluation using MRI movie may occur by image distortion caused by metallic artifacts.
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Affiliation(s)
- Erika Ozawa
- Department of Orthodontic Science, Tokyo Medical and Dental University (TMDU) Graduate School, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
| | - Ei-Ichi Honda
- Department of Oral and Maxillofacial Radiology, The University of Tokushima, Tokushima, Japan
| | | | - Hiroko Ohmori
- Department of Orthodontic Science, Tokyo Medical and Dental University (TMDU) Graduate School, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Kazuo Shimazaki
- Department of Orthodontic Science, Tokyo Medical and Dental University (TMDU) Graduate School, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Tohru Kurabayashi
- Department of Oral and Maxillofacial Radiology, Tokyo Medical and Dental University (TMDU) Graduate School, Tokyo, Japan
| | - Takashi Ono
- Department of Orthodontic Science, Tokyo Medical and Dental University (TMDU) Graduate School, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
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Kansy K, Hoffmann J, Bendszus M, Heiland S, Krisam J, Wohlfarth M, Mistele N, Geschwinder A, Gradl J. Tongue movement during articulation in magnetic resonance imaging: Findings in 20 healthy volunteers and a patient with anterior floor of the mouth squamous cell carcinoma. J Craniomaxillofac Surg 2017; 45:2046-2053. [PMID: 29037920 DOI: 10.1016/j.jcms.2017.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/27/2017] [Accepted: 09/11/2017] [Indexed: 11/28/2022] Open
Abstract
PURPOSE Combined ablative and reconstructive oral maxillofacial surgery involves a multitude of anatomical and functional structures for speech and swallowing. Although there are a few methods to objectively examine swallowing function, this is not true for speech. We describe the development of an objective visualization and measurement tool for magnetic resonance imaging (MRI) to evaluate speech and its first application in a patient. MATERIAL AND METHODS A total of 20 healthy patients and one patient with squamous cell carcinoma localized in the anterior floor of the mouth were included in the study. Examination included an MRI examination of a paced, defined set of fictive words representing all sounds of the German language. The patient underwent MRI preoperatively and 1, 3, 6 and 12 months postoperatively. MRI findings were correlated with speech intelligibility. RESULTS In sagittal planes, the correct identification of vowels and consonants was feasible and showed a high accordance between two independent observers and repetitions. Measurements for the patient showed significant deviations 1 month postoperatively but gradually decreased over time. Aberrant values were persistent for sound /s/. Findings correlated with clinical findings of speech intelligibility. CONCLUSION The presented tool seems to be promising for evaluating articulation in (tumor) patients.
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Affiliation(s)
- Katinka Kansy
- Department of Oral and Maxillofacial Surgery, Heidelberg University Hospital, Heidelberg, Germany.
| | - Jürgen Hoffmann
- Department of Oral and Maxillofacial Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Martin Bendszus
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Sabine Heiland
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Johannes Krisam
- Institute of Medical Biometry and Informatics, Department Medical Biometry, University of Heidelberg, Heidelberg, Germany
| | - Matthias Wohlfarth
- Department of Oral and Maxillofacial Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Nicole Mistele
- Department of Oral and Maxillofacial Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Anne Geschwinder
- Department of Otorhinolaryngology and Phoniatrics, Heidelberg University Hospital, Heidelberg, Germany
| | - Johann Gradl
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
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Traser L, Birkholz P, Flügge TV, Kamberger R, Burdumy M, Richter B, Korvink JG, Echternach M. Relevance of the Implementation of Teeth in Three-Dimensional Vocal Tract Models. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2017; 60:2379-2393. [PMID: 28898358 DOI: 10.1044/2017_jslhr-s-16-0395] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 02/23/2017] [Indexed: 06/07/2023]
Abstract
PURPOSE Recently, efforts have been made to investigate the vocal tract using magnetic resonance imaging (MRI). Due to technical limitations, teeth were omitted in many previous studies on vocal tract acoustics. However, the knowledge of how teeth influence vocal tract acoustics might be important in order to estimate the necessity of implementing teeth in vocal tract models. The aim of this study was therefore to estimate the effect of teeth on vocal tract acoustics. METHOD The acoustic properties of 18 solid (3-dimensional printed) vocal tract models without teeth were compared to the same 18 models including teeth in terms of resonance frequencies (fRn). The fRn were obtained from the transfer functions of these models excited by white noise at the glottis level. The models were derived from MRI data of 2 trained singers performing 3 different vowel conditions (/i/, /a/, and /u/) in speech and low-pitched and high-pitched singing. RESULTS Depending on the oral configuration, models exhibiting side cavities or side branches were characterized by major changes in the transfer function when teeth were implemented via the introduction of pole-zero pairs. CONCLUSIONS To avoid errors in modeling, teeth should be included in 3-dimensional vocal tract models for acoustic evaluation. SUPPLEMENTAL MATERIAL https://doi.org/10.23641/asha.5386771.
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Affiliation(s)
- Louisa Traser
- Institute of Musicians' Medicine, Freiburg University Medical Center, Germany
- Department of Otolaryngology, Freiburg University Medical Center, Germany
- Faculty of Medicine, University of Freiburg, Germany
| | - Peter Birkholz
- Institute of Acoustics and Speech Communication, Technische Universität, Dresden, Germany
| | - Tabea Viktoria Flügge
- Faculty of Medicine, University of Freiburg, Germany
- Department of Craniomaxillofacial Surgery, Freiburg University Medical Center, Germany
| | - Robert Kamberger
- Laboratory of Simulation, Department of Microsystems Engineering-IMTEK, University of Freiburg, Germany
| | - Michael Burdumy
- Faculty of Medicine, University of Freiburg, Germany
- Department of Medical Physics, Radiology, Freiburg University Medical Center, Germany
| | - Bernhard Richter
- Institute of Musicians' Medicine, Freiburg University Medical Center, Germany
- Faculty of Medicine, University of Freiburg, Germany
| | - Jan Gerrit Korvink
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Matthias Echternach
- Institute of Musicians' Medicine, Freiburg University Medical Center, Germany
- Faculty of Medicine, University of Freiburg, Germany
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Toutios A, Narayanan SS. Advances in real-time magnetic resonance imaging of the vocal tract for speech science and technology research. APSIPA TRANSACTIONS ON SIGNAL AND INFORMATION PROCESSING 2016; 5:e6. [PMID: 27833745 PMCID: PMC5100697 DOI: 10.1017/atsip.2016.5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Real-time magnetic resonance imaging (rtMRI) of the moving vocal tract during running speech production is an important emerging tool for speech production research providing dynamic information of a speaker's upper airway from the entire mid-sagittal plane or any other scan plane of interest. There have been several advances in the development of speech rtMRI and corresponding analysis tools, and their application to domains such as phonetics and phonological theory, articulatory modeling, and speaker characterization. An important recent development has been the open release of a database that includes speech rtMRI data from five male and five female speakers of American English each producing 460 phonetically balanced sentences. The purpose of the present paper is to give an overview and outlook of the advances in rtMRI as a tool for speech research and technology development.
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Affiliation(s)
- Asterios Toutios
- Signal Analysis and Interpretation Laboratory (SAIL), University of Southern California (USC), 3740 McClintock Avenue, Los Angeles, CA 90089, USA
| | - Shrikanth S Narayanan
- Signal Analysis and Interpretation Laboratory (SAIL), University of Southern California (USC), 3740 McClintock Avenue, Los Angeles, CA 90089, USA
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A pilot study on characterization of articulatory movements during fricative /s/ sound in an anterior open-bite subject: A tooth-visualized 3-T magnetic resonance imaging video evaluation. J World Fed Orthod 2015. [DOI: 10.1016/j.ejwf.2015.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Nunthayanon K, Honda EI, Shimazaki K, Ohmori H, Inoue-Arai MS, Kurabayashi T, Ono T. Use of an advanced 3-T MRI movie to investigate articulation. Oral Surg Oral Med Oral Pathol Oral Radiol 2015; 119:684-94. [PMID: 25956219 DOI: 10.1016/j.oooo.2015.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 02/20/2015] [Accepted: 03/09/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To develop a magnetic resonance imaging (MRI) movie to reveal the dynamic movement of articulators and teeth. STUDY DESIGN Five healthy females with normal occlusion participated in this study. Various concentrations of MRI contrast media (ferric ammonium citrate [FAC]) were tested for visualization of teeth, according to facial markers and with the use of a gel. Custom-made circuitry was connected to synchronize pronunciation of fricative sounds (/asa/) with scans. Three gradient echo sequences (True fast imaging with steady state precession [true FISP], FISP, and fast low angle shot [FLASH]) with a segmented cine were tested with the use of repetition times (TRs) of 9 ms and 31.5 ms. The MRI movie images were superimposed over the boundaries of teeth. The images produced during pronunciation, using the two different TRs (9 ms and 31 ms), were compared to assess the position of the lips and the tongue. RESULTS Images obtained using the FLASH sequence, with a TR of 9 ms or 31.5 ms, can be used for diagnostic purposes. A TR of 9 ms, with 161 continuous images acquired, produced the highest-quality images of teeth, with few artifacts present. Pronunciation of the consonant "s" was clearly discernable. CONCLUSIONS Our 3-T MRI movie system, with a temporal resolution less than 9 ms, can provide detailed information pertaining to variations in speech or oropharyngeal function.
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Affiliation(s)
- Kulthida Nunthayanon
- Graduate student, Graduate School, Orthodontic Science, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan; Lecturer, Faculty of Dentistry, Naresuan University, Phitsanulok, 65000, Thailand.
| | - Ei-ichi Honda
- Professor, Graduate School, Oral and Maxillofacial Radiology, University of Tokushima, 3-18-15, Kuramoto-cho, Tokushima, 770-8504, Japan; Lecturer, Graduate School, Oral and Maxillofacial Radiology, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Kazuo Shimazaki
- Assistant professor, Graduate School, Orthodontic Science, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Hiroko Ohmori
- Staff, Graduate School, Orthodontic Science, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Maristela Sayuri Inoue-Arai
- Lecturer, Maxillofacial Orthognathics, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Tohru Kurabayashi
- Professor, Graduate School, Oral and Maxillofacial Radiology, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Takashi Ono
- Professor, Graduate School, Orthodontic Science, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, 113-8549, Tokyo, Japan
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