摘要:

Electromyographic (EMG) activity was recorded from the masseter, the anterior temporal and the anterior digastric muscle on the right side of ten dental students when taps were administered upwards or downwards to the chin. The experiment was performed both with relaxed jaw muscles and with contracting depressor muscles. Pairs of intracutaneous platinum hook electrodes were used for the masseter and temporal muscles while concentric needle electrodes were inserted into the anterior digastric muscles. The mean latency of the jaw-jerk elicited in the relaxed masseter muscle when tapping downwards on the chin was 7.8 msec and in the temporal muscle 8.4 msec. The corresponding values of the latency during jaw opening against resistance from the investigator's finger was 8.2 msec and 9.0 msec. During upward tapping on the chin recordings from the anterior digastric muscle showed obvious changes in EMG activity, the latency ranging from 13 to 34 msec. Thus, compared to the latency of the jaw-jerk in the masseter and temporal muscles, which contain numerous muscle spindles, recordings from the anterior digastric muscle, where muscle spindles are thought to be either lacking or few in number, showed no signs of a monosynaptic reflex.

ISSN:0001-6357    

DOI:10.3109/00016358008997713

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor

摘要:

Patients receiving partial dentures were divided into three groups. One«maximum»group was taught and motivated, both individually and as a group, as thoroughly as possible. The second«medium»group was given instruction sheets describing the essential facts related to the cleaning and maintenance of teeth and dentures, but no individual instruction and motivation were provided. In the third«minimum»group the obtaining of information was left entirely to the initiative of the patients themselves. By the end of the period of treatment, the patients knowledge was in proportion to the amount of teaching they had received. As regards dental health behavior, the groups did not differ significantly from one another, although there were some indications that increased knowledge and motivation had promoted positive oral hygiene habits. A year after the completion of treatment the positive behavior habits were markedly fewer in all groups, and no longer bore any relation to the amount or type of instruction or motivation given.

ISSN:0001-6357    

DOI:10.3109/00016358008997714

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor

摘要:

The release of formaldehyde in an aqueous environment at 37°C from the surface of heat-polymerized, and auto-polymerized dough and pour type acrylic denture base materials was determined quantitatively. The analytical method used was based on determination of the reaction product of formaldehyde and dimedone by means of high performance liquid chromatography (HPLC), i.e. the method is spesific for formaldehyde. Chemical model reactions were carried out to simulate possible reaction mechanisms for the formation of formaldehyde in denture base polymers. The quantities of released formaldehyde was dependent on the processing conditions and composition of the material. Heat-polymerized denture base materials released considerably less formaldehyde than the auto-polymerized dough and pour types of materials.

ISSN:0001-6357    

DOI:10.3109/00016358008997715

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor

摘要:

This study aimed to compare caries-like lesions produced around fluoride-containing amalgam and conventional amalgam fillingsin vitro.Class V cavities were prepared in 90 extracted premolars, a fluoride-containing amalgam was inserted in 45 cavities (experimental group) and a conventional amalgam in 45 cavities (control group). After three months in an acidified gelatin solution, a longitudinal ground section passing through the cavity was prepared from each tooth. The sections were imbibed in water, quinoline and some in air before examination by polarized light microscopy. When imbibed in Canada balsam the sections were photographed and areas of demineralization in the enamel measured morphometrically. Some sections were studied by microradiography and electron microprobe analysis.Numerical scoring of the histological observations revealed significantly lower values for enamel and dentin cavity wall lesions in the experimental group, while the scores for the outer lesions were not statistically different between the two groups. The mean extension of enamel wall lesions was significantly lower in the experimental group, while no difference was observed in the outer lesions. A zone of increased mineralization in the enamel cavity walls was a frequent finding in the experimental group, This study has shown that fluoride-containing amalgam has an inhibitory effect on the development of experimental cavity wall lesionsin vitro.

ISSN:0001-6357    

DOI:10.3109/00016358008997716

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor

摘要:

The periodontal effects of food consistency and of experimental occlusal stresses were clinically studied with healthy and arteriosclerotic rats. Experimental arteriosclerosis was induced with a hypercholesterolemic diet continued for 6 - 12 months. By using food that was finely powdered and moistened, mechanical irritation of the periodontium was reduced to a minimum. The special occlusal and gingival irritants lasting six weeks were an occlusal overload with an overhigh amalgam filling, or an occlusal hypofunction caused by extracting the antagonist tooth.The arteriosclerotic animals with experimental occlusal stress had gingival changes adjacent to the loaded tooth distinctly more often than around the control tooth on the contralateral side of the mandible of the same animal (P<0.001). The changes seen were local redness and inflammation. and an excessive hyperplastic growth of the gingiva. The gingival changes on the stressed side in control animals were generally slight and the difference compared to the contralateral side was not statistically significant. The control animals showed recession of the gingiva more often than hyperplastic growth of same. In both groups of animals food impaction and deposit of calculus had increased around the teeth that were in occlusal hypofunction. The inflammatory changes were more frequent in the arteriosclerotic animals than in the controls. The cause of the deterioration in the ability to repair tissue damage in arteriosclerotic animals is discussed.

ISSN:0001-6357    

DOI:10.3109/00016358008997717

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor

摘要:

Hepatitis B., surface antigen (HBsAg) was detected by solid phase radioimmunoassay (RIA) in mixed saliva of 15 out of 50 antigenemic patients. The salivary antigen was present in low titers for a short period of time in the acute stage of illness. Occult blood was detected in most mixed saliva samples. In parotid saliva neither HBsAg nor occult blood was found. Salivary HBsAg is probably due to admixture of blood or exudate.

ISSN:0001-6357    

DOI:10.3109/00016358008997718

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor

摘要:

The adolescent growth of 212 randomly selected Swedish urban children has been investigated by using a graphical analysis of unsmoothed increments of height. The adolescent growth period has been divided into the pubertal spurt and the postpubertal period. On average, the pubertal spurt began at 10.0 years in girls, and 12.1 years in boys and ended at 14.8 years and 17.1 years, respectively. In both sexes peak height velocity occurred two years after the onset of the spurt (12.0 years and 14.1 years). Growth terminated at 17.5 years in girls and 19.2 years in boys. The standard deviation of the age at the occurrence of the various growth events is about one year in both sexes. The duration of the spurt did not differ between the sexes but the postpubertal period was significantly longer in girls. To include the total range of adolescent growth variability, the age range 6 - 20 years in girls and 9-23 years in Boys must be considered in a Swedish population.

ISSN:0001-6357    

DOI:10.3109/00016358008997719

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor