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Biomedical subjects

H Tezel

Publications and source records attributed to H Tezel.

5 recordsLinked to original sources
PubMed2004

A validated cold vapour-AAS method for determining mercury in human red blood cells.

A cold vapour-atomic absorption spectrometry (CV-AAS) method for determining mercury in dental students and clinical teaching staff red blood cells at a dental school using amalgam as a restorative material has been validated. A number of blood samples (n = 122) from dental students in years I to V, clinical teachers in restorative dentistry and controls were collected and analysed. Accuracy, linearity, precision (repeatability and reproducibility) and robustness of the method have been determined, and detection and quantification limits have been calculated. Linearity of response was verified for concentrations ranging from 5 to 40 microgL(-1) of mercury. Correlation coefficient of the calibration straight lines was always >/=0.99. Intra-day precision of the method gave coefficient of variation (CV) of 5.51%. Inter-day precision of the method calculated after analysis of five different concentrations of mercury standard solutions by the same analyst in different days and by two different analysts in different days gave coefficient of variation 4.89 and 5.44%, respectively. The accuracy of the method was calculated a CRM NIST 966 (toxic metals in bovine blood) total amount of mercury was found a concentration of 28.83 +/- 2.2 microgL(-1). Recovery was 89.27%. Robustness of the method evaluated by changing different experimental conditions under which analyses performed, fractional factorial design was done for assessing robustness of the method. Root mean square error was found out as 1.56. Limits of detection and quantification were 1.84 and 4.03 microg of Hg per litre of sample, respectively. Results show the suitability of the method for direct measurement of mercury in red blood cells and the importance of the working conditions for people dealing with amalgam at a dental school.

Cold Temperature↗
PubMed2001

Blood mercury levels of dental students and dentists at a dental school.

OBJECTIVE: To determine the blood mercury levels in dental students and clinical teaching staff in a dental school using amalgam as a restorative material. SETTING: A dental school in Ege University, Turkey surveyed during one academic year. SUBJECTS AND METHODS: Cross-sectional study of groups of dental students (n=92) in years I to V, clinical teachers in restorative dentistry (n=16) and controls (n=14). Mercury concentration was estimated in venous blood samples using a cold vapour atomic absorption method at the commencement and end of the academic year. Daily air mercury levels were determined in clinical and teaching areas by measuring the darkening of palladium chloride discs using spectrophotometry. RESULTS: There were statistically significant increases (p<0.001) in plasma mercury concentration between measurements in all groups at the end of the academic year. Red cell mercury levels were also consistently elevated. Although the highest levels of mercury were recorded in persons working with amalgam, increased levels were also found in subjects working in the teaching classrooms but not with amalgam (controls and first year students). CONCLUSION: Increased mercury levels appeared to be due to background exposure from spillage of mercury and amalgam residues on floors. Increased mercury hygiene and regular control of working atmosphere should be implemented to prevent mercury exposure in the dental pre-clinical laboratory.

Air Pollution, Indoor↗
PubMed1993

A comparative sealability study of different retrofilling materials.

The purpose of this study was to compare the sealing ability of high-copper amalgam, glass ionomer cement, and silver glass ionomer cement as retrofilling materials when used with and without varnish. Seventy extracted human single-rooted anterior teeth were instrumented and the root canals obturated with laterally condensed gutta-percha and sealer. The apical 3 mm of each root was resected and a 2 mm-deep apical Class I preparation cut. The roots were then randomly allocated to six groups of 10 teeth and retrofilled with one of the experiment materials. Group I comprised high-copper amalgam; group 2, high-copper amalgam with cavity varnish; group 3, glass ionomer cement without varnish; group 4, glass ionomer cement with varnish; group 5, silver glass ionomer cement without varnish; and group 6, silver glass ionomer cement with varnish. Two groups of five roots each were used as positive and negative controls. The root surfaces were coated with nail polish and specimens immersed in 2% methylene blue solution for 14 days. After vertical sectioning, dye penetration was examined under a stereomicroscope. The results of the study were analysed statistically. The sealing ability of the conventional glass ionomer cement with varnish was significantly better while dye penetration was higher in silver glass ionomer cement without varnish group than the other groups (P < 0.01).

Acid Etching, Dental↗
PubMed1993

The penetration of root canal sealers into dentinal tubules. A scanning electron microscopic study.

The purpose of this study was to evaluate the effect of smear layer on penetration of four root sealers into dentinal tubules. Sixty-four, recently extracted, human maxillary and mandibular incisors were used. Following removal of the crowns, the pulps were extirpated and the root canals instrumented. The teeth were then divided into two groups. The teeth in the control group were irrigated with saline solution and the experimental group treated with EDTA and NaOCl. Each main group was then divided into four sub-groups and the root canals filled with Diaket, N2 Universal, SPAD and Forfenan as recommended by the manufacturers. The teeth were split longitudinally and examined using scanning electron microscopy. A quantitative assessment was made of sealer penetration into the dentinal tubules in the coronal, middle and apical parts of each root canal. It was observed that the smear layer obstructed the penetration of the tubules by the sealers. However, in the experimental group, the penetration into dentinal tubules was better with Diaket, N2 and SPAD, than with Forfenan (P < 0.01). It was concluded that this penetration could be affected by physical and chemical properties of root canal filling materials.

Analysis of Variance↗