Structural Mechanical Analysis and Evaluation for Extension of Teeth Lifetime

Higashimachi, Takao; Suga, Kenichi; Sasahara, Hisato

doi:10.2493/jjspe.75.418

Cited by 4 publications

(3 citation statements)

References 3 publications

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“…Material data of the analysis model are shown in Table 1 [3][4][5]. The anatomical parts name number in the table corresponds to the number in Fig.…”

Section: Materials Datamentioning

confidence: 99%

Improvement of sound conduction efficiency from the viewpoint of vibration characteristics of the human middle ear

Higashimachi¹,

Liu²,

Oshikata³

et al. 2017

Int. J. DNE

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When the middle ear is damaged by various ear diseases, the linkage of the auditory ossicles may be reconstructed using the column article called the columella, or artificial stapes. In tympanoplasty, operations are carried out based on the workmanship and experience of the surgeon. We have proposed a new method for estimating the hearing restoration effect prior to the tympanoplasty operation. In this method, a geometric model of the human middle ear is constructed using SolidWorks based on CT scanning data. Then, frequency response characteristics of the stapes displacement in sound conduction are calculated using finite element harmonic vibration analysis. The hearing restoration effect can be estimated by a comparison of the differences in the stapes displacement between the reconstruction model and a healthy subject. Through the study of our method, it has been clarified that a maximum displacement of 5.0 nm of a III-i type operation model for chronic otitis media achieves a response of about 98% compared to a healthy subject.Furthermore, several models in which an annular ligament becomes more rigid through otosclerosis and related operation models using artificial stapes are constructed and analyzed. As much as the annular ligament stiffened, it followed that sound conduction efficiency decreased. Frequency characteristics of the conductive hearing loss due to otosclerosis thus could be reproduced. According to operation models using artificial stapes, it is possible that the stapes displacement increases, that is, the sound conduction efficiency is improved, more than the result in which an annular ligament becomes highly rigid.From the vibration analysis of these models, our proposed estimation method for reconstruction of the auditory ossicles was verified. Through this study, the optimization of structures and materials for columella and artificial stapes becomes possible. Finally, the efficacy of predicting the hearing restoration effect prior to an operation was verified.

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“…Material data of the analysis model are shown in Table 1 [3][4][5]. The anatomical parts name number in the table corresponds to the number in Fig.…”

Section: Materials Datamentioning

confidence: 99%

Improvement of sound conduction efficiency from the viewpoint of vibration characteristics of the human middle ear

Higashimachi¹,

Liu²,

Oshikata³

et al. 2017

Int. J. DNE

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show abstract

“…It became clear that the stress concentration occurred just under the contact point, which was similar to the actual growth point of the dental caries. Furthermore, it was clarified that stress concentration was closely related to the eminence of the alveolar bone, attrition, and wedge-shaped defects [1].…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional finite element analysis of the human middle ear and an application for clinics for tympanoplasty

Higashimachi

Shiratake

Maeda

et al. 2013

Surface Effects and Contact Mechanics XI

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The geometric model around the middle ear which includes the tympanic membrane, tympanic cavity, auditory ossicles, several ligaments, and tensor was constructed using SolidWorks. The auditory ossicles consist of malleus, incus and stapes. The computerized tomography (CT) scan data around the middle ear was converted into DICOM (Digital Imaging and Communication in Medicine) data, then into STL data. This STL data was imported to SolidWorks in order to generate the geometric model. The sound pressure through the tympanic membrane was applied to this model in a three-dimensional finite element analysis using COSMOSWorks. Then, the mechanical influence of the sound pressure upon the middle ear was analyzed. The deformation of the middle ear and the displacement of the stapes under the sound pressure of 120 dB were clarified. The displacement of the bottom of the stapes in the direction of the axis is about 3.1 nanometers which becomes a standard value of the hearing ability evaluation. In the internal ear, the stapes vibration is transmitted to the labyrinthine fluid in the cochlea where electrical signals are generated. Finally, it is recognized in the brain as sound. For example, in the case that the medical device is substituted for the deficient auditory ossicles, it is possible to estimate hearing ability by comparing to what degree the displacement of stapes changes. This kind of approach makes it possible to propose a new medical treatment for the recovery of conductive hearing loss.

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“…It became clear that the stress concentration occurred just under the contact point, which is similar to the actual growth point of dental caries. Furthermore, it was clarified that stress concentration was closely related to eminence of the alveolar bone, attrition and wedge-shaped defects [1].…”

Section: Introductionmentioning

confidence: 99%

Finite Element Analysis of External, Middle and Inner Ear under Loads through Temporomandibular Joint

Higashimachi

Toriya²,

Suga³

2012

KEM

Self Cite

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A structural analysis model including the temporomandibular joint (TMJ), external auditory canal, tympanic membrane, auditory ossicles and cochlea was made. Loads through the TMJ were applied to this model in three-dimensional finite element analysis. It became clear that stress concentration occurred at the lower portion of the external auditory canal, superior tympanic portion (attic), incus long crus, stapes crus and inlet of cochlea. The lower portion of the external auditory canal and attic are favourite sites of cholesteatoma (pearl tumour). Incus long crus and stapes crus are favourite sites of auditory ossicular defects, which are the cause of otitis media. Damage of the cochlea entrance causes high-frequency hearing loss which is age-related.

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Structural Mechanical Analysis and Evaluation for Extension of Teeth Lifetime

Cited by 4 publications

References 3 publications

Improvement of sound conduction efficiency from the viewpoint of vibration characteristics of the human middle ear

Improvement of sound conduction efficiency from the viewpoint of vibration characteristics of the human middle ear

Three-dimensional finite element analysis of the human middle ear and an application for clinics for tympanoplasty

Finite Element Analysis of External, Middle and Inner Ear under Loads through Temporomandibular Joint

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