Sadao Sato

Publications (3)2.37 Total impact

• Article: A three-dimensional computerized tomography study into the morphological interrelationship between anterior and posterior guidance and the occlusal scheme in human Caucasian skulls

  Hélder Nunes Costa, Rudolf Slavicek, Sadao Sato
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  ABSTRACT: BackgroundThe articular eminence of the glenoid fossa together with the occlusal guiding surfaces represent two fundamental determinants of mandibular movement and even though subject to numerous investigations the relationship between both structures still remains unclear today. The purpose of this 3D investigation was to characterize the inclinations of the articular eminence, measure the inclinations of maxillary occlusal guiding surfaces, investigate the occlusal scheme present and examine the relationship between anterior and posterior guidance. MethodsSeveral three-dimensional measurements obtained through computerized analysis of virtual models of 163 human skulls reconstructed from cone-beam computed tomography (CBCT) images were analyzed and correlated. ResultsThe inclinations of the articular eminence and of the occlusal guiding surfaces revealed large individual variation. Second molars showed the lowest inclination values with a significant number of first and second molars presenting buccally inclined guiding elements. Anterior guidance showed slightly higher inclination values than posterior guidance. Significant correlations were found between the inclination of the articular eminence and the posterior passive centric line of occlusion. ConclusionsThe occlusal scheme of sequential guidance with front canine dominance was confirmed. Inferring a direct etiologic anatomical interrelationship between anterior and posterior guidance may be an oversimplification of the craniomandibular system. KeywordsDental occlusion, centric–Odontometry–Cross-sectional study–Humans–Cone-beam computed tomography
  international journal of stomatology & occlusion medicine 04/2012; 4(1):10-19.
• Article: A computerized tomography study of the morphological interrelationship between the temporal bones and the craniofacial complex.

  Helder Nunes Costa, Rudolf Slavicek, Sadao Sato
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  ABSTRACT: The hypothesis that the temporal bones are at the center of the dynamics of the craniofacial complex, directly influencing facial morphology, has been put forward long ago. This study examines the role of the spatial positioning of temporal bones (frontal and sagittal inclination) in terms of influencing overall facial morphology. Several 3D linear, angular and orthogonal measurements obtained through computerized analysis of virtual models of 163 modern human skulls reconstructed from cone-beam computed tomography images were analyzed and correlated. Additionally, the sample was divided into two subgroups based on the median value of temporal bone sagittal inclination [anterior rotation group (n = 82); posterior rotation group (n = 81)], and differences between groups evaluated. Correlation coefficients showed that sagittal inclination of the temporal bone was significantly (P < 0.01) related to midline flexion, transversal width and anterior-posterior length of the basicranium, to the anterior-posterior positioning of the mandible and maxilla, and posterior midfacial height. Frontal inclination of the temporal bone was significantly related (P < 0.01) to basicranium anterior-posterior and transversal dimensions, and to posterior midfacial height. In comparison with the posterior rotation group, the anterior rotation group presented a less flexed and anterior-posteriorly longer cranial base, a narrower skull, porion and the articular eminence located more superiorly and posteriorly, a shorter posterior midfacial height, the palatal plane rotated clockwise, a more retrognathic maxilla and mandible, and the upper posterior occlusal plane more inclined and posteriorly located. The results suggest that differences in craniofacial morphology are highly integrated with differences in the positional relationship of the temporal bones. The sagittal inclination of the temporal bone seems to have a greater impact on the 3D morphology of the craniofacial complex than frontal inclination.
  Journal of Anatomy 03/2012; 220(6):544-54. · 2.37 Impact Factor
• Article: [Bruxism--a function of the masticatory organ to cope with stress].

  Rudolf Slavicek, Sadao Sato
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  ABSTRACT: Bruxism is generally defined as a parafunctional clenching and grinding action between the upper and lower teeth. During this activity, extremely strong forces can be applied for time periods exceeding those of functional mastication. These biomechanical loads create many dental problems, such as abfractions, hypersensitivity, periodontal distraction, and temporo-mandibular dysfunction. Researchers studying Bruxism have long discussed psychic stress and emotional tension. It has also been indicated that an aggressive biting is associated with a significant attenuation of the stress-induced increase of nor-adrenalin turnover in the brain, of the striatal DOPAC contents and with the prevention of stomach ulcer formation in experimental animals. The concept of stress management based on the psychological background of Bruxism and the benefits attributable to masticatory muscle activity in attenuating stress-related symptoms such as stomach ulcer. The clenching and bruxing function of the masticatory organ is an emergency exit during periods of psychic overloading. Therefore, occlusion of the masticatory organ contributes significantly to an individual's ability to manage stress. Bruxism in proper dentition can be recognized as a valid system prophylaxis for all stress related diseases.
  Wiener Medizinische Wochenschrift 01/2005; 154(23-24):584-9.