Comparison of Jaw-muscle Bite-force Cross-sections Obtained by Means of Magnetic Resonance Imaging and High-resolution CT Scanning

Cross-sectional areas of the jaw muscles were determined by means of magnetic resonance imaging (MRI) in 12 healthy adult male subjects. These findings were compared with the cross-sectional areas of the jaw muscles of the same subjects, obtained by means of computer tomography (CT) in a previous study (Weijs and Hillen, 1985). Significant correlations (r>0.7) were found between the CT and MRI cross-sections of the masseter, medial pterygoid, and temporalis muscles. The low correlation between the CT and MRI cross-sections of the lateral pterygoid muscle could be explained by the different imaging techniques (slice thickness) of MRI and CT scanning. CT and MRI cross-sectional areas of the masseter and medial pterygoid muscle (but not the temporalis muscle) showed highly positive and significant correlations with the maximal voluntary bite force. In living subjects, the cross-sections of the masseter and medial pterygoid muscles can be visualized with CT and MRI. Compared with CT, MRI has some advantages, such as the absence of adverse effects (no radiation) and the excellent soft-tissue imaging. Furthermore, a series of frontal, horizontal, sagittal, and angulated MRI scans can be made without modification of the patient's position, facilitating reconstruction of the jaw muscles.

[1]  T. L. James,et al.  Magnetic resonance imaging: absence of in vitro cytogenetic damage. , 1985, Radiology.

[2]  K. R. Jones,et al.  Patient absorbed dose for Philips Tomoscan 300 CT scanner. , 1985, The British journal of radiology.

[3]  G. Schumacher,et al.  Funktionelle Morphologie der Kaumuskulatur , 1961 .

[4]  B. Saltin,et al.  Morphology of the brachial biceps muscle and elbow flexion in man. , 1983, Acta physiologica Scandinavica.

[5]  A. J. Palfrey.  Die Plazenta des Menschen. , 1984 .

[6]  H. J. de Jongh,et al.  Forces acting on the mandible during bilateral static bite at different bite force levels. , 1980, Journal of biomechanics.

[7]  Carr Ab,et al.  Magnetic resonance imaging of the temporomandibular joint: preliminary work. , 1987 .

[8]  B. Hillen,et al.  Relationship between the physiological cross-section of the human jaw muscles and their cross-sectional area in computer tomograms. , 1984, Acta anatomica.

[9]  W. Proffit,et al.  Occlusal Forces in Normal- and Long-face Adults , 1983, Journal of dental research.

[10]  B. Hillen,et al.  Physiological cross-section of the human jaw muscles. , 1985, Acta anatomica.

[11]  G. S. Throckmorton.  Quantitative calculations of temporomandibular joint reaction calculations of temporomandibular joint reaction forces. II: The importance of the direction of the jaw muscle forces , 1985 .

[12]  L. Olson,et al.  Extraneuronal binding of catecholamines and 3,4-dihydroxyphenylalanine (dopa) in salivary glands. , 1967, Acta physiologica Scandinavica.

[13]  F A Baragar,et al.  Predicted pattern of human muscle activity during clenching derived from a computer assisted model: symmetric vertical bite forces. , 1985, Journal of biomechanics.

[14]  P. Schantz,et al.  Muscle fibre type distribution, muscle cross-sectional area and maximal voluntary strength in humans. , 1983, Acta physiologica Scandinavica.

[15]  H. Haxton.  Absolute muscle force in the ankle flexors of man , 1944, The Journal of physiology.

[16]  J. Ahlgren.  Mechanism of mastication , 1966 .

[17]  B. Ingervall.  Facial morphology and activity of temporal and lip muscles during swallowing and chewing. , 1976, The Angle orthodontist.

[18]  J. Schenck,et al.  Normal and abnormal temporomandibular joint: MR imaging with surface coil. , 1986, Radiology.

[19]  B Ingervall,et al.  Relation between facial morphology and activity of the masticatory muscles. , 1974, Journal of oral rehabilitation.

[20]  M. Hagberg,et al.  Regression analysis of electromyographic activity of masticatory muscles versus bite force. , 1985, Scandinavian journal of dental research.

[21]  G. Throckmorton,et al.  Quantitative calculations of temporomandibular joint reaction forces--I. The importance of the magnitude of the jaw muscle forces. , 1985, Journal of biomechanics.

[22]  B Hillen,et al.  Correlations between the cross-sectional area of the jaw muscles and craniofacial size and shape. , 1986, American journal of physical anthropology.

[23]  M. J. Noruésis,et al.  SPSS-X advanced statistics guide , 1985 .

[24]  S. Harms,et al.  The temporomandibular joint: magnetic resonance imaging using surface coils. , 1985, Radiology.

[25]  B. Hillen,et al.  Relationships between Masticatory Muscle Cross-section and Skull Shape , 1984, Journal of dental research.

[26]  A. Hannam,et al.  Relationships between the size and spatial morphology of human masseter and medial pterygoid muscles, the craniofacial skeleton, and jaw biomechanics. , 1989, American journal of physical anthropology.

[27]  L. Dessner.  A clinical method for determination of riboflavin standard in urine after a test dose and the riboflavin excretion of clinically normal subjects. , 1952, Acta odontologica Scandinavica.

[28]  V. Sassouni.  A classification of skeletal facial types. , 1969, American journal of orthodontics.

[29]  D. Hatcher,et al.  Development of mechanical and mathematic models to study temporomandibular joint loading. , 1986, The Journal of prosthetic dentistry.

[30]  B. Ingervall,et al.  A pilot study of the effect of masticatory muscle training on facial growth in long-face children. , 1987, European journal of orthodontics.

[31]  S. Carlsoo.  Nervous coordination and mechanical function of the mandibular elevators; and electromyographic study of the activity, and an anatomic analysis of the mechanics of the muscles. , 1952, Acta odontologica Scandinavica. Supplementum.

[32]  R. Maughan,et al.  Strength and cross‐sectional area of human skeletal muscle. , 1983, The Journal of physiology.

[33]  G. Throckmorton,et al.  Biomechanics of differences in lower facial height. , 1980, American journal of orthodontics.

[34]  E. Møller.  The chewing apparatus. An electromyographic study of the action of the muscles of mastication and its correlation to facial morphology. , 1966, Acta physiologica Scandinavica. Supplementum.

[35]  J. Valk,et al.  Basic principles of nuclear magnetic resonance imaging , 1985 .

[36]  R. Yemm,et al.  Changes in human masseter and medial pterygoid muscles with age: a study by computed tomography. , 1987, Gerodontics.

[37]  M Ringqvist,et al.  Isometric bite force and its relation to dimensions of the facial skeleton. , 1973, Acta odontologica Scandinavica.