Deutsche Stomatologie (Berlin, Germany : 1990)最新文献

The clinical relevance of the dimensional behavior of six different gamma-2-free silver amalgam products was examined in comparative in vitro and in vivo trials. Dye penetration tests, roughness measurements, and inspection of the marginal fit using a scanner electron microscope all showed that the results of the in vivo and the in vitro trials were in good agreement and that there was no significant difference between the various products tested, despite the fact that they differed both in morphology and in composition. Copalite exerts a favorable influence on the marginal fit of amalgam restorations, not only in laboratory trials, but also clinically. The results obtained show that the behavior of an amalgam with respect to changes in volume is not the sole criterion by which its quality is to be judged. Amalgams with a pronounced contraction tendency will seal the marginal gap with their corrosion products (SnCl). Here copalite serves as a temporary stand-in. There was no leakage of metal ions from the restoration into the dentin for any of the products tested, including those with a high copper content.

Indications and contraindication are discussed as well as necessary clinical and labor-technical suppositions for the application of an adhesive-bridge on the basis of a literature study. According to long-year personal experiences with this therapy method the patients treatment as well as a special technical procedure are described.

Yearly cross-sectional studies from 1985 to 1990 of 16-18 years old apprentices indicate a constant high caries prevalence of about 10 DMF/T. The yearly caries increment is also high like it is documented by longitudinal investigations of 152 apprentices, and it depends from the caries experience in the past. Only 9-17% of the youngsters had a yearly caries increment of greater than or equal to 3 D/T. Individual caries risk requires individual preventive dental services.

Aluminium oxide ceramics, apart from Titan, must be regarded at present as the most favourable material for dental implants, due to the fact it has adequate parameters of stability in addition toits inert biocompatibility. It is reported on dental implants of BIONIT capable of being produced in deries for the most various applications, and the results obtained in clinical routine.

In this study the influence of four different pretreatments showed significant differences on the permeability of cut dentin. On the average the application of 25% polyacrylic acid increased the permeability by approximately 10 percent, the application of 34% polyacrylic acid by 30 percent. The treatment with 0.1% chlorhexidin-digluconate produced no change of permeability. Calciumhydroxide suspension reduced the permeability by 15 percent and diminished the increase caused by phosphoric acid significantly.

The functional tooth axis is--contrary of the anatomical tooth axis--defined as follows: The effect of force in its direction causes a maximum of desmodontal fibres being stressed on drawing. After measure of an upper caninus, an upper and a lower molar mathematical models of the teeth and the desmodont of force are calculated with a computer simulation. A variety of functional tooth axes which are not identical with the anatomical ones, result for each tooth. The possible functional axes yield a variety which signifies the biological tolerance. This tolerance causes that many individual forms of occlusion don't have any pathological effect on the desmodont.

The authors followed the effect of chromcobalt alloy on human cells cultured in vitro. They found out that corrosion increases the cytotoxicity of this alloy, meanwhile the perfectly laboratory elaboration, especially polishing of substitution decreases the cytotoxicity. We recommend for the complex cytotoxicity review, to test the metals and alloys also after laboratory elaboration, it means in the condition it is passed on to the patient.

A new method of sculpting casting patterns for secondary conical or parallel telescopic crowns was tested in a comparative study. After deep drawing of a carrier foil together with a spacer foil the space maintainer was removed out of the carrier cap. The space between the cap and the primary crown was filled with a light-curing resin liquid. After plymerisation the occlusal gap between this cap and the primary crown was measured in comparison to deep drawn Adapta carrier foils. The result is that the new method gives most accurate casting patterns.

Orthodontic tooth movement of upper first molars was performed in twelve aged (500 days old) rats. It was demonstrated by histomorphologic findings as well as by vital polychrome staining that the remodelling process of the periodontal tissues in the aged animals was qualitatively similar to that in younger ones. The first molar in all animals was tipped mesially, while its mesial root was intruded. According to the vital polychrome staining the bone formation rate at the mesio-apical bone surface of the mesial root was determined as 7-8 microns per day. After 14 days comprehensive root resorption in the pressure zone distal of the bifurcation was found.

314 young patients with sports-related maxillofacial trauma were classified into 34.7% facial fractures, 35.9% dentoalveolar trauma and 28.4% soft tissue injuries. In the alpine regions the distribution of fractures by aetiology is dominated by skiing accidents. 43% of the midface fractures are due to fractures of the zygomatic bone and arch. Children up to ten years are more prone to dentoalveolar trauma. Opportune preventive measures are recommended.