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Biomedical subjects

K Nilner

Publications and source records attributed to K Nilner.

61 records · Page 4Linked to original sources
PubMed1982

Reproduction of details using dental stones and investment material in impressions of elastomers and waxes.

In the fabrication of crowns and inlays it is very important that all the details of the impression are exactly reproduced by the cast. These requirements prevail between elastomeric impression materials and dental stones as well as between waxes and investment materials. Inadequate filling of the details of the impression will result in rounded inner corners of the casting, which then may not properly seat on the prepared tooth. Two brands of elastomeric impression material, dental stone, wax, investment material and wetting agent were chosen to study the reproduction of details. A master model of stainless steel, shaped like a truncated cone with a convex top and 60 degrees threads, was used. The shape of this model made it possible to make microscopic measurements of the reproduced detail of the threads. No significant difference, by different prepouring treatment of the impressions was found in reproducing details with elastomeric impression materials and dental stones. All combinations of elastomeric impression materials and dental stones reproduced, however, significantly more details than combinations of waxes and investment materials. The relevance of transferring conclusions from the laboratory investigation to clinical conditions are discussed as well as the clinical value of reproducing details.

Calcium Sulfate↗
PubMed1981

Studies of electrochemical action in the oral cavity.

A method for in vivo measurements of potentials and polarizations of metallic dental restorations was presented. The precision of this method allowed for calculation to be made of the electrochemical action in the oral cavity in terms of currents created at contact between metallic restorative materials. With this method, an epidemiological investigation was performed on persons, who had received dental treatments including extensive metallic restorations. Those persons suffering from oral symptoms allegedly caused by oral galvanism were not found to have higher electrochemical action in the oral cavity than persons, selected as a control, without symptoms ascribed to oral galvanism. Persons ailing from this type of symptoms showed, however, lower threshold levels for electric stimulation, examined with an electrogustometric method, than persons without symptoms. Finally, determination of the saliva concentrations of various metallic components with atomic absorption spectrophotometry did not reveal any differences between persons with or without metallic restorations. Neither were any correlations found between saliva ion concentrations and the magnitude of currents created at metallic contact between dental restorations.

Adolescent↗
PubMed1978

Potential and polarization measurements in vivo of oral galvanism.

Galvanic currents within the oral cavity may have harmful effects on biological tissues. In the present work 16 patients with different kinds of oral and other discomfort and pain which they attributed to oral galvanism were investigated. The potential and polarization of each metal restoration within reach of a platinum probe were measured versus a reference electrode. A recording of these measured values permits a calculation of the currents which may pass between the teeth. A control group of patients with no subjective symptoms of galvanism in the oral cavity was also investigated. The results of the electrochemical measurements showed that conditions for oral galvanism existed within the individuals of the patient group as well as within the control group. One remarkable observation was that the metallic restorations often consisted of different electrically isolated areas with different electrochemical properties. This and other factors influencing oral galvanism are discussed.

Adult↗
PubMedDate not supplied

A six-year follow-up study of maxillary overdentures on osseointegrated implants.

This study comprised a clinical and radiological examination of two groups of 14 patients receiving overdentures of the same design on osseointegrated implants. The mean follow-up period was 82 months and 35 months in the two groups the fixture success rate was 84% and 85% and the marginal bone loss 0.97 mm and 1.29 mm respectively. The follow-up of the two groups was guided by several clinical parameters and apart from the loss of fixtures and adjustments of the attachment system only a few complications were registered. The results show that this treatment method is a successful alternative in the treatment of the edentulous maxillae.

Aged↗
PubMedDate not supplied

Five-year evaluation of posterior all-ceramic three-unit (In-Ceram) FPDs.

PURPOSE: The purpose of this study was to investigate whether the properties of the In-Ceram material are adequate for use in posterior three-unit fixed partial dentures (FPD) and to evaluate the clinical method regarding preparation technique, design, and choice of cement. MATERIALS AND METHODS: Eighteen patients were treated with a total of 20 posterior three-unit FPDs according to the In-Ceram technique. The FPDs were constructed with bilateral support and one pontic and were all replacing one premolar or a molar (11 replacing premolars and 9 replacing molars). They were evaluated 6 months after delivery and then once yearly. RESULTS: Eighteen of the 20 FPDs (90%) showed no defects at any of the follow-up examinations and were functioning well after 5 years. No caries or signs of gingivitis or periodontitis exceeding those found in the rest of the dentition were registered. CONCLUSION: The In-Ceram technique is, in a 5-year perspective and adopted for three-unit FPDs, an acceptable treatment alternative. Further studies must, however, be performed before the material can be recommended for more extensive restorations than the FPDs included in this study.

Adult↗