Kazuto Terada

Bio: Kazuto Terada is an academic researcher from The Nippon Dental University. The author has contributed to research in topics: Dental arch & Mandible. The author has an hindex of 14, co-authored 52 publications receiving 569 citations. Previous affiliations of Kazuto Terada include Niigata University.

A new method of predicting mandibular length increment on the basis of cervical vertebrae.

Abstract: The purpose of this study was to establish an equation to predict incremental mandibular length on the basis of the analysis of the cervical vertebrae in a single cephalometric radiograph ...

Three-dimensional analysis of condylar hyperplasia with computed tomography.

Abstract: Three-dimensional surface reconstruction imaging from CT scans was used to study the deformity of the mandible in six patients with mandibular asymmetry. High-resolution axial CT scans of the mandible were obtained using Somatom-DR3 (Siemens). COSMOZONE-2SA (Nikon) with PC-9801VX21 (NEC) was used to reconstruct the three-dimensional images. The six patients were divided into two groups. One group was classified as unilateral hybrid forms and the other group was classified hemimandibular elongation on the diagnostic criteria of Obwegeser and Makek (1986). In the three-dimensional surface reconstruction, exact location and the degree of the deformity in the region from the ascending ramus to the condylar head and the lingual aspect from the ascending ramus to the mandibular body were accurately represented. In addition, the three-dimensional images could be easily rotated arbitrarily, precise evaluation could be done at every part of the mandible. On diagnosis, the mandibular morphology classified into the unilateral hybrid forms was presumed to vary from case to case even in the same classification.

Influence of third molar space on angulation and dental arch crowding

Abstract: The influence of the third molars on mandibular incisor crowding has been extensively studied but remains controversial. The purpose of this study was to ascertain whether, in Mongolian subjects, the lower third molar can affect anterior crowding and/or the inclination of teeth in the lower lateral segments. Panoramic radiographs, 45 oblique cephalograms, and dental casts were taken from Mongolian subjects (age range 18.3-24.1 years, mean 21.0 years) exhibiting impaction of all four third molars and an Angle Class I molar relationship. The Ganss ratio was calculated using panoramic radiographs, whereas the gonial angle and angulation of lower canines, premolars and molars were measured using 45 oblique cephalo- grams. Little's index of irregularity was calculated using dental casts. Significant relationships between the angula- tion of the third and second molars and between the first molars and second premolars were found. Conversely, there was no significant correlation between the angulation of third molars, first premolars and canines. The Ganss ratio calculations showed that the lower first and second molars and the second premolars inclined mesially if there was insufficient space for the lower third molars. However, there was no significant correlation between Little's index of irregularity and third molar angulation. Furthermore, although the third molar influences the lateral segments, no obvious relationship between the third molar and anterior crowding was observed. Therefore, the angulation of the third molar appears not to cause anterior crowding.

Handbook of Chemistry and Physics

Abstract: There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

The influence of implant diameter and length on stress distribution of osseointegrated implants related to crestal bone geometry: a three-dimensional finite element analysis.

Abstract: Statement of problem Load transfer mechanisms and possible failure of osseointegrated implants are affected by implant shape, geometrical and mechanical properties of the site of placement, as well as crestal bone resorption. Suitable estimation of such effects allows for correct design of implant features. Purpose The purpose of this study was to analyze the influence of implant diameter and length on stress distribution and to analyze overload risk of clinically evidenced crestal bone loss at the implant neck in mandibular and maxillary molar periimplant regions. Material and methods Stress-based performances of 5 commercially available implants (2 ITI, 2 Nobel Biocare, and 1 Ankylos implant; diameters of 3.3 mm to 4.5 mm, bone-implant interface lengths of 7.5 mm to 12 mm) were analyzed by linearly elastic 3-dimensional finite element simulations, under a static load (lateral component: 100 N; vertical intrusive component: 250 N). Numerical models of maxillary and mandibular molar bone segments were generated from computed tomography images, and local stress measures were introduced to allow for the assessment of bone overload risk. Different crestal bone geometries were also modelled. Type II bone quality was approximated, and complete osseous integration was assumed. Results Maximum stress areas were numerically located at the implant neck, and possible overloading could occur in compression in compact bone (due to lateral components of the occlusal load) and in tension at the interface between cortical and trabecular bone (due to vertical intrusive loading components). Stress values and concentration areas decreased for cortical bone when implant diameter increased, whereas more effective stress distributions for cancellous bone were experienced with increasing implant length. For implants with comparable diameter and length, compressive stress values at cortical bone were reduced when low crestal bone loss was considered. Finally, dissimilar stress-based performances were exhibited for mandibular and maxillary placements, resulting in higher compressive stress in maxillary situations. Conclusions Implant designs, crestal bone geometry, and site of placement affect load transmission mechanisms. Due to the low crestal bone resorption documented by clinical evidence, the Ankylos implant based on the platform switching concept and subcrestal positioning demonstrated better stress-based performance and lower risk of bone overload than the other implant systems evaluated. (J Prosthet Dent 2008;100:422-431)

Evaluation of Three-Dimensional Changes in Pharyngeal Airway Following Isolated Lefort One Osteotomy for the Correction of Vertical Maxillary Excess: A Prospective Study

Abstract: Orthognathic surgery involves movement of jaws in all three planes, and this being a part of airway complex, displacement of jaws can influence the dimension of airway at all levels. Lefort one osteotomy surgery with superior repositioning is a common procedure done for patients with vertical maxillary excess The purpose of this study was to evaluate the three-dimensional volumetric changes in airway after lefort one impaction surgery using three-dimensional cone beam computed tomography (3D-CBCT) in patients with vertical maxillary excess (VME). A prospective analysis of 15 patients who underwent isolated lefort one impaction surgery was done with pre-operative (T0) and 3-months (T1) post-operative 3D-CBCT scans. Airway was divided into three segments, nasopharyngeal, velopharyngeal and oropharyngeal. Volumetric analysis of all these segments was done before and after surgery. Paired ‘t test’ was used to assess the mean difference in airway volume and area between T0 and T1. One-way ANOVA was used to check the mean percentage difference in airway volume and area among the three segments. The mean percentage of nasopharyngeal volume difference was − 0.6299 ± 0.9146%, velopharyngeal volume difference was − 0.5205 ± 1.107%, oropharyngeal volume difference was − 1.492 ± 2.745%. Though volume and area of pharyngeal airway were decreased after maxillary impaction surgery in all three segments of airway studied, they were not statistically significant. Among the three segments of airway studied, oropharyngeal airway volume has shown the highest post-surgical reduction though statistically insignificant. ESS scores were within normal limits. Hence, we are of the opinion that there is lack of evidence to conclude that the patients undergoing lefort one superior repositioning for the treatment of VME might develop significant narrowing of PAS that may predispose the patient to breathing disorders.