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Biomedical subjects

K Safavi

Publications and source records attributed to K Safavi.

15 recordsLinked to original sources
PubMed2000

Influence of mixing vehicle on dissociation of calcium hydroxide in solution.

The antimicrobial effects of aqueous preparations of calcium hydroxide have been demonstrated in the past. Calcium hydroxide, when dissolved in water, dissociates into hydroxide and calcium ions. The presence of hydroxide ions in a solution makes it antimicrobial. Recently it was shown that the use of glycerin as a mixing vehicle facilitates placement of calcium hydroxide in the root canals. The influence of nonaqueous mixing vehicles on the dissociation of calcium hydroxide is not clearly understood. In this study the conductivity of aqueous and nonaqueous solutions of calcium hydroxide was measured. The conductivity values for saturated solutions of calcium hydroxide in water was 7.3+/-3 mS/cm. The conductivity of calcium hydroxide in pure glycerin or propylene glycol was essentially zero. It was concluded that use of nonaqueous mixing vehicles may impede the effectiveness of calcium hydroxide as a root canal dressing.

Anti-Infective Agents, Local↗
PubMed1999

Adherence of enamel matrix derivatives on root-end filling materials.

It was recently shown that application of enamel matrix derivatives (EMDs) on denuded root dentin promotes periodontal regeneration. EMD is shown to adhere to the etched dentin, but its adherence to root-end filling materials is not known. The purpose of this study was to evaluate the adherence of a commercially available EMD product to root-end filling materials. Dentin sections were embedded in blocks made of acrylic resin. Cavities were prepared in similar acrylic resin blocks and were filled with amalgam, IRM, or composite resin. EMD was labeled with radioactive iodine and applied to the surfaces of the dentin sections, freshly made fillings, or acrylic resin controls. The specimens were rinsed, and the amount of radioactive iodine was determined in a gamma counter. Substantial amounts of EMD adhered to dentin sections. EMD adherence to amalgam and IRM was significantly less than to dentin or composite resin.

Cementogenesis↗
PubMed1998

Large datasets: common uses and caveats.

BACKGROUND: Increasingly, large collections of pre-existing data are being used to analyze the occurrence, burden, and health care resources directed to the management of various skin diseases. OBJECTIVE: This article discusses a number of different types of large datasets along with their common uses. Various concerns about the use of this information are also discussed. CONCLUSION: Although large datasets provide significant statistical power with readily available data, there are significant concerns, particularly regarding data quality and statistical analysis. Readers need to be aware of how an investigator has addressed these issues. Furthermore, the profession needs to be cognizant of very legitimate public concerns regarding confidentiality of personal information.

Databases, Factual↗
PubMed1994

Data resources for epidemiology of skin diseases.

Among existing data sets the First National Health and Nutrition Examination Survey (NHANES-I) stands out for its large sample size and detailed examination of the skin. However, because NHANES-I employed many different examiners and no uniform diagnostic criteria, the quality of the data is variable. Furthermore, the survey was conducted in the 1970s and does not contain information necessary to answer some currently relevant epidemiologic questions. Future data collection efforts will have to be planned to address specific hypotheses. In addition, future dermato-epidemiologic studies will have to pay careful attention to diagnostic accuracy.

Data Collection↗
PubMed1991

Tissue reaction to endodontic materials: methods, criteria, assessment, and observations.

The purpose of this study was to develop methods and criteria for the testing of the biocompatibility of endodontic materials. One hundred twenty-one teeth from 12 baboons (Papio anubis) were used to test three sealers: AH26, Kerr pulp canal sealer, and Kloroperka N.O. Gutta-percha cones were used as solid core in all cases. Under disinfected conditions, access preparation was performed, and with working length approximately 1.0 mm short of the foramen, the instrumentation of the root canal was started, using sodium hypochlorite (1%) for irrigation. After the root canals were cleaned and shaped, they were obturated with gutta-percha cones and the sealer, and by lateral condensation technique. Histologic periapical reactions were evaluated at 1, 7, 30, 365, 730, and 1095 days. The methods and criteria used were adequate for ranking of the biocompatibility of the tested materials in the short and long periods. At short observation periods (1 to 7 days) AH26 caused severe reactions, and Kerr pulp canal sealer and Kloroperka N.O., moderate and mild reactions, respectively. At 2- and 3-year observation periods the ranking was AH26, mild; Kerr pulp canal sealer, moderate; and Kloropercha N.O., severe.

Animals↗