摘要:

A study of morphologic variability was made for maxillary incisor lingual fossa depth. The problem of variability is discussed, and new methods for the statistical treatment of variability are presented. Possibly, the best procedure to express biologic variability is to present SDs, CVs, Xs, ranges, RCs, and the logarithmic graphic method of the relationship between CV and X. No sex differences in variability could be demonstrated. Maxillary centrals and laterals in the Eskimo were found to have relatively equal variability. This is seen in connection with the great functional demand on Eskimo incisors, giving less reduction of the laterals, a possible simultaneous commencement of calcification for I1sup and I2sup, and possible genetic drift. Comparison of variability for six populations shows no racial differences in variability. Variability is not found to increase with inbreeding. Population comparisons do not confirm little reduction in the Eskimo to be associated with high variability. Genetic drift might be the explanation of the homogeneity of maxillary incisor lingual fossa depth in East Greenland Eskimos.

ISSN:0001-6357    

DOI:10.3109/00016358309162332

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

Veneers were made from sheets consisting of a three-dimensional network of sintered ultrafine glass fibers. The sheets were molded by a vacuum-pressure technique and then impregnated with a liquid resin. Impregnation was performed with a method that enabled the depth of penetration to be monitored. The resin was cured with UV radiation under N2protection. By the use of TiO2-containing resins the veneer achieved an enamel-like appearance. An in vitro toothbrush dentifrice abrasion test showed a high wear resistance and persisting surface luster. Scanning electron and light microscopy showed fairly smooth and flat light-reflecting glass structures in the surface.

ISSN:0001-6357    

DOI:10.3109/00016358309162333

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

One of the purposes of mastication is to break down the food and enlarge the area of food particles. A method is described by which the masticatory efficiency is estimated by calculating the area of a chewed test material, gelatin-hardened by formalin. When test pieces, after being chewed, are placed in a water-soluble dye, the dye will diffuse into the particles, and consequently the dye concentration in the surrounding solution will decrease. The concentration of the dye solution is read from a photometer. A close correlation was found between the gelatin particle area and the reduction of the dye solution concentration. The method will be applied in clinical studies.

ISSN:0001-6357    

DOI:10.3109/00016358309162334

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

Previous investigations have indicated that striated-duct cells react to stimulation with an apocrine secretion, morphologically demonstrated by bleb-like projections of the apical cytoplasm. Since bleb formation as an ultrastructural feature also has been debated and sometimes interpreted as a fixation artifact, it was considered essential to extend the studies by exposing the submandibular gland to X rays to establish whether such treatment would have any influence on the formation of blebs. The material used in the present study consisted of rat submandibular glands exposed to X rays in the range of 200—1800 rad. The glands were examined by both SEM and TEM. The duct cells exposed to 200 rad appeared normal, with no sign of alteration in their ability to produce blebs, whereas duct cells exposed to 750 rad showed no sign of bleb formation. Some of the duct cells exposed to 1800 rad showed considerable morphological changes, consistent with oncotic transformation. The results support the conclusion that bleb formation is a normal morphological feature and not an artifact. This study also indicates that the functional activity of the cells is reduced after exposure to X rays.

ISSN:0001-6357    

DOI:10.3109/00016358309162335

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

In a previously published study on the effect of an alcalase on development of denture plaque, two different methods were used to quantify plaque on the fitting surface of maxillary dentures. Both methods were based on scoring of photographs at×10 magnification. In one of the methods the percentage area was estimated with 10% intervals from 0% to 100%. By the other method dentures were ranked according to cleanliness based on area and on degree of staining of plaque. The number of dentures in each of the 14 treatment periods was 14 or 15. The present study was conducted to determine the reliability of the two methods. Reliability of the two methods was determined by using Pearson's correlation coefficient and Kendall's tau. Both intra- and inter-examiner reliability was high. A high correlation between the two methods was also demonstrated.

ISSN:0001-6357    

DOI:10.3109/00016358309162336

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

The contribution of local blood flow to the buffering properties of the periodontal ligament was examined in 15 anesthetized rabbits. The position of the tooth was recorded by an ultrasonic transit time technique, and local vascular pressures and volumes were altered by electrical stimulation of the cervical sympathetic nerves. The unloaded tooth was shifted into a slightly intruded position by nerve stimulation, and from this position, intrusion movements evoked by 5- to 10-g loads were found to be 10—15% smaller than before the stimulation. Tooth mobility was unaffected by 20—30 mm Hg reductions in mean arterial pressure, but similar decreases in mobility as evoked by nerve stimulation were observed when the pressure was brought down to 10—25 mm Hg. This procedure also produced about the same intrusive shift of the unloaded tooth. Most likely, the sympathetic nerve activity decreased tooth mobility by causing a fall in periodontal vascular pressures, thereby moving the tooth into a position where it was more resistant to further, load-induced intrusion.

ISSN:0001-6357    

DOI:10.3109/00016358309162337

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

The occurrence of pores and fatigue fractures in flame-soldered joints of dental gold was measured using fractograms and metallographic preparations. All soldered joints contained pores localized mainly in the solder material adjacent to casting/solder and solder/solder interfaces. The porosity portion of these regions was 20—40 volume per cent, consisting chiefly of pores smaller than 0.1 mm. The fatigue fractures were near`y always situated in the same regions or along the casting surfaces themselves.

ISSN:0001-6357    

DOI:10.3109/00016358309162338

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

The temporomandibular joint (TMJ) and dental occlusion were investigated clinically and radiographically in 59 patients aged 23—83 (mean, 58) years with general joint disease. Forty-nine had rheumatoid arthritis (RA), mostly of long duration. The patients were divided into four groups by type of dentition. Radiographic TMJ abnormality was found in about 4 of 5 patients with RA, in both the dentate and the edentulous group. The abnormality was mainly destructive with productive signs, but in the edentulous group erosive and asymmetrical changes occurred more often. Almost complete restriction of the condylar translation and severely restricted mouth opening (≤30 mm) rarely occurred, although the translatory motion was restricted in several patients. Many of these had a satisfactory mouth opening (<40 mm). Occlusal changes—-various degrees of anterior bite opening—-were reported by about one fourth of both the dentate patients and the complete denture wearers. One patient had occlusal contact on the second molars only. Anterior bite opening occurred only in patients with radiographic TMJ abnormality, including 5 of the 6 patients with complete mandibular head destruction.

ISSN:0001-6357    

DOI:10.3109/00016358309162339

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

In a previous paper it was maintained that the effect of the permanent use of an anterior partial bite-raising splint was an intrusion of the front teeth and an eruption of the others. However, the effect might have been merely a change in the inclination of the front teeth. The present study comprised the same material as earlier. Linear and angular changes in the position of upper and lower incisors were measured on cephalometric radiographs. In the upper jaw a possible average proclination occurred, whereas in the lower jaw no or only a very small retroclination took place. The values were well within the method error, and it was concluded that the effect of the splint had been one of intrusion of the upper and lower front teeth and not merely a change in their inclination.

ISSN:0001-6357    

DOI:10.3109/00016358309162340

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

A continuation of the bibliography 1907—1975, published as supplementum 73 of the Acta Odontologica Scandinavica and ofActa Odontol. Scand.1977, 35, 225—228; 1978, 36, 175—180; 1979, 37, 177—180; 1980, 38, 329—332; 1981, 39, 179—183; 1982, 40, 377—380; 1983, 41, 315—319.

ISSN:0001-6357    

DOI:10.3109/00016358309162341

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor