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Biomedical subjects

D F Vieira

Publications and source records attributed to D F Vieira.

At least 19 recordsLinked to original sources

[An introductory vision of the quality of life in work].

The present paper refers to an introductory study about "Quality of work life" (QWL), subject which requires a growing importance in certain organizations. At first it is a discussion on the origin of this movement and its conceptualization by some authors. Afterwards two approaches to QWL are exposed--the classical and the situational. This is a classification used by the authors themselves to emphasize the original, conventional concept of QWL and to differentiate it from the second approach which is really situational and which has a broader sense, adapting to reality and to the context of the organization. The paper concludes with a reflection on the future courses of organizations, its human resources and QWL.

Humans

Influence of pressure and vibration during cementation.

Vibration, applied at the beginning of cementation, improves the fit of MOD inlays and cast complete crowns when they are compared to the same castings cemented without vibration. The Medart pressure applicator produced better adaptation. Orange wood blocks and Burlew disks produced similar results. They were less efficient than the Medart pressure applicator. Cotton rolls resulted in the highest fit discrepancy.

Cementation

Fluoride release and physical properties of a fluoride-containing amalgam.

1. The amount and percentage of fluoride released from amalgam were less for the 1:1.6 alloy/mercury ratio than for the 1:1 ratio. 2. Higher fluoride concentrations resulted in a greater quantity but lower percentage of fluoride released from the amalgam. 3. Longer immersion times resulted in a greater amounts and percentages of released fluoride. However, the fluoride released per hour decreased with immersion time. 4. Immersion of the amalgam in lactic acid caused a greater release of fluoride than immersion in distilled water. 5. Disintegration of the amalgam was greater in lactic acid than in distilled water. The contribution of calcium fluoride to weight loss was greater in water than in lactic acid, indicating a corrosive effect for lactic acid. 6. The higher calcium fluoride content (2 per cent) decreased the compressive strength of the amalgam but did not alter the dimensional change.

Calcium Fluoride

Changes in physical properties of joined gypsum fragments.

(1) The dimensional change in joined fragments of gypsum models was small. The highest percentage occurred with zinc phosphate cement. (2) The cyanoacrylate cements produced the strongest bonds. Mendent Formula VI and the epoxy cement were least effective. (3) The bond strength was generally greater after 24 hours. The exceptions were Mendent Formula VI and zinc phosphate cement. (4) Different gypsum products responded differently to bonding agents. Some are superior for plaster of Paris; others for artificial dental stone.

Calcium Sulfate

Physical properties of dental amalgam containing metal pins.

No type of pin inclusion investigated in this study produced consistent increases or decreases in the strength of amalgam specimens under a variety of loading conditions and specimen ages. However, comparison of relative values for specimens tested under the same conditions showed that the highest fracture loads were found more often for specimens containing threaded gold pins than for any other type of specimen.

Chemical Phenomena

Tissue reaction to dispersion alloy amalgam.

Dental amalgam implanted in rat connective tissue is injurious for the first 16 days. At 32 days, the implanted amalgam is tolerated. The increased copper content of Dispersalloy did not evoke a more serious response of the connective tissue than Fine Cut or Spheraloy amalgam.

Animals

[Composite resins].

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Chemical Phenomena

[Casting].

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Dental Alloys