Biomedical subjects
Publications and source records attributed to D R McArthur.
The title compound, C23H23NO2SSi, at 100 K adopts a boat conformation which brings the C-H bond of an axial phenyl substituent into proximity [C...N = 3.376 (1) A] with the aziridine lone pair. The factors which favour this conformation for bicyclo[3.1.0]hexane systems are considered.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A method has been described to make a second set of complete dentures for a patient. The second set of dentures will reflect relined tissue contours, use of manufactured artificial teeth, and trial-packed, heat-processed denture bases. The new dentures are of equal quality to the original dentures.
All patients have loose nonkeratinized unattached mucosa in the anterior labial vestibule. The degree of possible distortion varies with each patient and with different recording techniques. Some distortion is possible in all patients. Common errors made when manipulating this tissue during impression procedures for complete dentures have been described. An effort to compensate for the errors in the finished denture will not correct them. Manipulation of the mucolabial fold must be done correctly during the border molding procedure. If not, the only recourse may be to reline the denture, and care should be taken not to repeat the errors.
Three methods were used to obtain a ratio of the maxillary to the mandibular anterior teeth, with results of 1.29, 1.30, and 1.31. It can be concluded that a ratio of 1.30 is sufficient to determine the approximate width of the six maxillary anterior teeth when given the size of the mandibular natural anterior teeth. This ratio should be valid to select a maxillary denture mold of sufficient width mesiodistally to obtain a Class I canine relationship. However, the ratio may need a slight adjustment to compensate for the intentional disocclusion of the maxillary denture teeth with the natural mandibular teeth. In Fig. 1 the canine to canine measurement of the mandibular anterior teeth was 35 mm; when multiplied by a factor of 1.30, a maxillary measurement of 45.5 mm is obtained. The denture teeth were to be set with approximately 1 mm of horizontal overjet and 1 mm of vertical overlap (Fig. 2), therefore a slightly larger mold of 48.5 mm was chosen (Fig. 3). This maxillary mold produced a Class I canine relationship (Fig. 4). The 48.5 mm ratio of the chosen maxillary mold to the mandibular measurement of 35 mm yielded a ratio of 1.38. When this ratio of 1.38 is applied, the desired prosthetic mold is not always available. There is a range of acceptability above and below the desired ratio.(ABSTRACT TRUNCATED AT 250 WORDS)
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The average width of a natural maxillary central incisor is 8.92 mm. This value is determined from the results of three studies of natural dentitions. The average width of a mandibular central incisor is 5.5 mm. The average ratio produced by dividing the average maxillary central incisor width by the average mandibular incisor width is 1.62. The factor of 1.5 times the width of a mandibular central incisor produces a maxillary central incisor width that is too narrow. The width of a mandibular central incisor plus half the width of the mandibular lateral incisor also produces a maxillary central incisor width that is too narrow. There may be a tendency to undersize the maxillary prosthetic dentition. The ratio of 1.62 can be used to select the appropriate width for a missing maxillary central incisor when given the width of the mandibular central incisor. This ratio of 1.62 is also valuable to verify the dimension of a selected artificial maxillary central incisor when the patient complains that the tooth is too large. If substitutions or adjustments are made in the mold, the desired canine-to-canine measurement produced by the ratio range of 1.3 to 1.38 reported in Parts I and II of this study should be maintained.
A technique has been described for the fabrication of full coverage restorations for existing removable partial dentures. This method requires that the patient be deprived of the removable prosthesis during the fabrication of the fixed replacement unit. Clearly, this may not always be possible or desirable, however, when it is possible, the end result outweighs the inconvenience to the patient.
This technique can be used to avoid the making of preliminary impressions for complete dentures in patients with abnormally small oral openings. With this method, the patient must have existing dentures, and the border extensions must be adequate to serve as individualized impression trays.
The posterior maxillary osteotomy is a versatile and useful treatment alternative for a variety of dentofacial conditions. Its place in the management of bilateral distal-extension removable partial denture construction has been described along with a report of treatment of a patient.
This article describes three methods for fabricating stabilized occlusion rims for close interarch spaces. To utilize these methods, the dentist must anticipate the lack of space and request that the rims be fabricated by one of the methods outlined prior to the maxillomandibular relations appointment.
This article outlines a technique for the fabrication of metal posterior tooth blocks which have tooth-colored facings of acrylic resin or dental porcelain. The technique is applicable for all removable dental restorations but has special applicability for the chronic bruxing patient who has a natural dentition opposing the removable partial denture.
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It was hoped that it might be possible to establish some standard or starting point which could be used by future investigators to judge adequate levels of radiopacity of radiopaque denture-base materials. Aluminum and copper were used to define a suitable radiopacity scale. The scale was represented by two sets of specimens--one of regular outline and uniform thickness, the other of irregular shape and tapering thickness. Radiographs of the chest and abdominal regions of a cadaver were exposed, with the specimens placed on the film side and then on the opposite side of the cadaver. The results showed that it was more difficult to locate the beveled irregular specimens, that there was little difference between the chest and the abdomen with respect to ease of locating the same objects, and that the closer an object is to the film the easier it is to locate. For 95 per cent observability, an object should have a level of radiopacity at least equal to that produced by 0.20 mm. of copper.