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Biomedical subjects

A Oden

Publications and source records attributed to A Oden.

42 records · Page 3Linked to original sources
PubMed1989

Effects of bonding agent types and incremental techniques on minimizing contraction gaps around resin composites.

In this in vitro study, large rectangular cavities were prepared on the proximal surfaces of human premolars with cervical margins placed beyond the cemento-enamel junction. Before the insertion of resin composite, the cavity walls were treated with Bowen's system, Scotchbond, or Gluma combined with different bonding agents. Various incremental techniques were tested. The contraction gap was determined by use of the resin impregnation technique: After polymerization shrinkage, a low-viscosity resin with a fluorescent additive was applied to the cervical and occlusal margins to penetrate the contraction gap. After being ground, the width of fluorescent resin could be measured with a microscope. All combinations of materials and techniques produced contraction gaps at the cervical wall. The range for mean width of the impregnated gap at the cervical wall was from 5 to 13 microns. The lowest mean value was obtained for Gluma in combination with Clearfil Bonding Agent. Placement of the composite in two increments significantly reduced the gap width. No reduction was achieved when a three-step insertion technique was used.

Composite Resins↗
PubMed1988

Prognostic importance of somatic and psychosocial variables after a first myocardial infarction.

The prognostic importance of somatic and psychosocial variables after a first myocardial infarction was studied in 201 consecutive Gothenburg, Sweden men below 61 years of age who had survived a first myocardial infarction between December 1976 and December 1978. The maximum follow-up time was 100 months. The prognostic importance of somatic, social, and psychological variables was related to the endpoints of death, nonfatal reinfarction, and total events. During follow-up, 48 deaths and 37 nonfatal recurrences occurred. Four variables, none of them significantly correlated with each other, were related to risk of an endpoint. Being single increased risk of death (p less than 0.01) and risk of all events (p less than 0.001), whereas an index reflecting infarct size was correlated to risk of death (p less than 0.001). A prognostic index based upon data available at three months after the myocardial infarction (angina pectoris, hypertension, serum aspartate aminotransferase (S-ASAT) maximum, and smoking) was correlated to risk of nonfatal reinfarction (p less than 0.05). Use of sedatives was also related to risk of reinfarction (p less than 0.05) and to risk of total event (p less than 0.05). The probability of death, reinfarction, and total event was estimated within two and five years after the infarction for all combinations of the variables that were related to risk of an endpoint. It was thus demonstrated that the predictive power increased over time and that the somatic and psychosocial variables independently added information.

Adult↗
PubMed1987

Considerations for peptic ulcer trials.

A drug trial concerned with peptic ulcer treatment has to be carefully planned to make possible a valid conclusion. Calculations of the number of patients required have to be made early. This depends upon factors such as: if the comparison is to be made between two active drugs or an active drug and a placebo, if the aim is to show that two treatments are almost equal or if a certain difference is expected, the number of groups to be compared, and if intermediate checks are to be made. Thus, from a few dozen patients up to several thousand may be needed. If a multicenter dosing is adopted, which is often necessary, the minimum number of patients required from each centre should be specified and a good reporting system has to be created. When presenting the results, it is preferable to calculate a confidence interval for the difference between the treatments--especially in small studies where the risk is false conclusions would otherwise be large.

Clinical Trials as Topic↗
PubMedDate not supplied

Premature death in patients operated on for primary hyperparathyroidism.

To investigate long-term survival after operation for primary hyperparathyroidism, a follow-up study was performed on 896 consecutive patients in whom this diagnosis had been clinically and microscopically verified. These patients were operated on in the years 1953-1982. Their mean age at operation was 57.3 years [standard deviation (SD) 13.1], overall cure rate was 97.0%, and postoperative mortality was 0.89%. Follow-up was 99.8% complete by the end of 1986. Mean follow-up time was 12.9 years (SD: 6.1). Two-hundred ninety-four patients were deceased, which was 118 more than in a control group (p less than 0.001). The latter was based on Swedish population statistics, matched for age, sex, and calendar year. Each year, the control group was the same size as the hyperparathyroid population. The risk of premature death remained increased (p less than 0.001) even after exclusion of poor-risk patients having their hyperparathyroidism diagnosed when being treated or followed because of other serious diseases. The main causes of premature death for the hyperparathyroid patients were cardiovascular and malignant diseases. Both occurred more often than in the control group (p less than 0.001). The results demonstrate that primary hyperparathyroidism causes damage that is not reversed by surgery.

Adolescent↗
PubMedDate not supplied

On whole blood viscosity measurements in healthy individuals and in rheumatoid arthritis patients.

Different methods of measuring whole blood viscosity using a couette rotational viscometer were compared to establish its use in clinical rheumatological practice. The relationship between blood viscosity and hematocrit was approximately exponential and no significant differences in the slopes were found between healthy controls and rheumatoid arthritis patients. Correction of native blood viscosity to a standard hematocrit of 40% by extrapolation from a standard regression curve, established by concentration/dilution of samples from healthy persons to correct for hematocrit differences and at shear rate 92s-1, was the best method for differentiating between viscosities of patients and controls. It was also the least laborious method, requiring the smallest amounts of blood and having the lowest method error. Native blood viscosity, corrected blood viscosity, plasma viscosity and red cell aggregation were all significantly higher and hematocrit significantly lower in rheumatoid arthritis patients than in controls.

Adolescent↗