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[en] This study investigated maxillary third molars and their relation to the maxillary sinus using panoramic radiography and cone-beam computed tomography (CBCT). A total of 395 maxillary third molars in 234 patients were examined using panoramic radiographs and CBCT images. We examined the eruption level of the maxillary third molars, the available retromolar space, the angulation, the relationship to the second molars, the number of roots, and the relationship between the roots and the sinus. Females had a higher frequency of maxillary third molars with occlusal planes apical to the cervical line of the second molar (Level C) than males. All third molars with insufficient retromolar space were Level C. The most common angulation was vertical, followed by buccoangular. Almost all of the Level C molars were in contact with the roots of the second molar. Erupted teeth most commonly had three roots, and completely impacted teeth most commonly had one root. The superimposition of one third of the root and the sinus floor was most commonly associated with the sinus floor being located on the buccal side of the root. Eruption levels were differently distributed according to gender. A statistically significant association was found between the eruption level and the available retromolar space. When panoramic radiographs showed a superimposition of the roots and the sinus floor, expansion of the sinus to the buccal side of the root was generally observed in CBCT images
[en] The purpose of this study was to examine the inferior expansion of the maxillary sinus floor following maxillary molar extraction. Cone beam computed tomographic images of 59 subjects were used to evaluate the height difference of the maxillary sinus floor between extraction sites and contralateral dentate sites. The height of the maxillary sinus floor was defined as the vertical distance to the Frankfort plane from the level of the anterior nasal spine to the most inferior point of the sinus floor. We examined the difference in sinus pneumatization according to the number of missing teeth and the vertical relationship of the molar roots to the sinus floor. The inferior expansion of the maxillary sinus floor was 1.20 ± 1.86 mm on the maxillary first molar and 1.90 ± 2.42 mm on the maxillary second molar. Increased expansion was observed in cases where two proximate molars were extracted. There was no significant difference in sinus pneumatization following extraction according to the vertical relationship of the molar roots to the sinus floor. The results of this study confirm that sinus pneumatization occurs following maxillary molar extraction. In situations where pneumatization can affect treatment after molar extraction, three-dimensional radiography should be considered.
[en] The author observed a case of osteogenic sarcoma in a 11-year-old female with complaint of painful swelling on face in right side. The observed results were as follows: 1. Large hematoma was observed, and patient complained painfull swelling on c/c site. 2. Predisposing factor of osteogenic sarcoma was not clear, but patient had history of extraction before patient visiting infirmary of our dental collage. 3. Serologic findings were not specific, and serum aldaline level was normal. 4. Radiographic findings were as follows: a. Diffuse faint radiopacit in the lesion. b. Bony destruction and increased radiopacity in right antrum. c. Displacement of multiple teeth on involved area(i. e no 12, 15, 55, 16, 17, 18) d. Increased periodontal space in single tooth(no 13) e. Destruction of bony crypt on involved teeth(no 13, 14, 15, 17, 18) f. Loss of lamina dura of three teeth in involved area(no 11, 12, 16) 5. Computed tomographic findings were as follows: a. Large calcific and heterogenous component mass in the Rt. maxillary sinus, and this mass extending to Rt. maxilla, alveolar bone, ethmoid sinus. b. Soft tissue bulging in to Rt. side nasal cavity and oral cavity. c. Bone destruction of maxillary sinus wall and Rt. alveolar bone.
[en] Electronic total station can simultaneously measure angle and distance, together with the appropriate calculation methods and operating skills, able to efficiently complete the survey work, this paper based on practical experience, theoretical analysis, based on total station introduced in setting out a few boring in the skills and the measurement of total station in the construction layout for accuracy. (authors)
[en] The invention relates to a method and an apparatus for simultaneously drilling a bore and testing the sub-soil formations thus passed through. The apparatus according to the invention is characterized in that it contains a non-rotating injection head supported by a hoisting hook and carrying the rod driving a train of drilling rods carrying a drilling bit and a test probe adapted to receive signals emitted by the sub-soil formation in the process of drilling, said head being connected through a cable to a recording device. This cable is inserted in the non-rotating portion of the injection head through a packing which can be untightened and which prevents the drilling sludges from leaking while at the same time locking the cable so as to prevent same from rotating while the drilling rods are in the process of rotating. Such an apparatus is suitable, in particular, for using a probe adapted to measure pressure, or the specific gravity of an electric feature or the radioactivity of the sub-soil formations passed through
[fr]L'invention concerne un procede et un appareil pour le forage d'un puits et l'essai simultane des formations traversees. L'appareil selon l'invention est caracterise par une tete d'injection non rotative supportee par le crochet de levage et supportant la tige d'entrainement d'un train de tiges de forage portant un trepan et une sonde d'essai pour recevoir des signaux provenant de la formation foree et connectee par un cable a l'appareil d'enregistrement. Le cable penetre dans la partie non rotative de la tete d'injection a travers un presse-etoupe pouvant etre desserre et empechant les fuites de la boue de forage et fixant en meme temps le cable pour empecher sa rotation pendant la rotation du train de tiges de forage. Un tel appareil convient en particulier pour l'utilisation d'une sonde mesurant la pression, la densite, une caracteristique electrique ou la radioactivite des formations traversees
[en] The objective of drillhole ER-12-1 was to determine the hydrogeology of paleozoic carbonate rocks and of the Eleana Formation, a regional aquitard, in an area potentially downgradient from underground nuclear testing conducted in nearby Rainier Mesa. This objective was addressed through the drilling of well ER-12-1 at N886,640.26 E640,538.85 Nevada Central Coordinates. Drilling of the 1094 m (3588 ft) well began on July 19, 1991 and was completed on October 17, 1991. Drilling problems included hole deviation and hole instability that prevented the timely completion of this borehole. Drilling methods used include rotary tri-cone and rotary hammer drilling with conventional and reverse circulation using air/water, air/foam (Davis mix), and bentonite mud. Geologic cuttings and geophysical logs were obtained from the well. The rocks penetrated by the ER-12-1 drillhole are a complex assemblage of Silurian, Devonian, and Mississippian sedimentary rocks that are bounded by numerous faults that show substantial stratigraphic offset. The final 7.3 m (24 ft) of this hole penetrated an unusual intrusive rock of Cretaceous age. The geology of this borehole was substantially different from that expected, with the Tongue Wash Fault encountered at a much shallower depth, paleozoic rocks shuffled out of stratigraphic sequence, and the presence of an altered biotite-rich microporphyritic igneous rock at the bottom of the borehole. Conodont CAI analyses and rock pyrolysis analyses indicate that the carbonate rocks in ER-12-1, as well as the intervening sheets of Eleana siltstone, have been thermally overprinted following movement on the faults that separate them. The probable source of heat for this thermal disturbance is the microporphyritic intrusion encountered at the bottom of the hole, and its age establishes that the major fault activity must have occurred prior to 102.3+0.5 Ma (middle Cretaceous)
[en] Reliable forecasting of stability and deformation parameters of 'Ukrytie' fundament determine its operation. Necessary data were obtained on the base of characteristic values of soils which resulted from engineering-geological research
[en] A method is derived to determine principal stress magnitude and orientation at a particular location by using calculated secondary principal stresses that were obtained from overcoring stress relief measurements. A computer program based on this method is used to calculate the principal stress at various locations in Rainier Mesa, Nevada Test Site, using previously reported secondary principal stress values. (U.S.)
[en] Cleidocranial dysplasia (previously known as cleidocranial dysostosis) is a well-known, rare and hereditary skeletal disorder characterized by a variety of dental abnormalities and as its name implies, striking involvement of the cranial vaults and clavicles. A 17-year-old female who presented with short stature and prolonged retention of deciduous teeth, subsequent delay in eruption of permanent teeth is described. She could touch her shoulders together at the midline anteriorly. Diagnostic procedures showed hypoplasia of the maxillary and zygomatic bones, open fontanelles and sutures, and aplasia of the clavicles. The paranasal sinuses were absent or underdeveloped. Characteristically, she had near parallel-sided borders in the ascending ramus of the mandible and abnormal-shaped, the slender pointed coronoid process. The zygomatic arches had a downward bend and discontinuity at the zygomaticotemporal suture area. Radiographic and clinical investigations of her cranial and skeletal abnormalities revealed features of cleidocranial dysplasia.
[en] The physical bases of laboratory, borehole, and field methods of studying rocks are presented. The information is based on a study of the nuclear properties of the rocks and the use of radioactive radiation sources. The techniques and methodology of studies made by these methods and the interpretation of the data obtained are described