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Sialoprotein is one of the most abundant non-collageneous and phosphorylated glycoproteins in human. This protein plays an important role in the structure of human teeth. The aim of this project is to measure the amount of dentin Sialoprotein in the healthy and decay teeth to evaluate the variation in the teeth structure. In this investigation 50 decay teeth has been collected from patients referred to the clinic. The dentin was separated and placed in liquid Nitrogen. One gram of each dentin was washed with distilled water for 30 mins and subsequently the dentin was powdered, and relocated to the gaunidin-Hcl tris buffer, and incubated at 4°C for 48 hrs. The dentin powder was centrifuged at 3000 g for 20 mine. The supernatant was discarded, and the samples again was centrifuged at 10000 g. Finally one ml of this supernatant transferred to the sepharose column and washed with gaunidin-Hcl tris at 1 ml/min. The fractions obtained by chromatography was monitored by electrophoresis. The amount of decay teeth Sialoprotein was 17.23±1.45 ng/l and in the healthy teeth was 26.39±4.27 ng/l. The results from this study indicate that the Sialoprotein content in patient dentin decreased by about 1.5 time compared normal subjects.

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3 Beta-Hydroxy-delta-5-steroid dehydrogenase is an important key enzyme of steroid hormone biosynthesis, which is involved in catalyzing the conversion of pregnenolone to progesterone in the biosynthesis of steroid sex hormones. This is the fourth enzyme in the steroid hormone biosynthesis pathway to be identified as an autoantigenic target. Pregnenolone is incubated with several concentrations of whole testis homogenate. The reaction mixture containing the pregnenolone, NAD and iodonitrotetrazolium in 0.15 M Tris-HCL buffer (pH=7.7) and the enzyme extract from testis of rat was incubated for 1.5 h at 36°C. Absorbance at 495 nm was determined by a spectrophotometer. pH optimum and time incubation for this enzyme was 7.99 and 1.5 h respectively. The Kmax was 5.3×10^-6 and Vmax was 3.11×10^-6 nmol/mg/min. Our results were in good agreement with those reported previously.

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Background & Objective: Due to volatile property of monomer from Methylmethacrylate and its well known toxic side effects, in case of absorption via skin or respiratory system. Also, due to allergic reactions of it, consideration of suitable ventilation systems and using protective methods is very important. To decrease direct contact with it, the capabilities of technician and improves his health and work place, we investigate relationship between Methanol level and exposure to Methylmethacrylate. Materials & Methods: In a case-control (In vivo) study of 32 dental laboratory technicians in Babol and Sari before and after working and 32 normal subjects, urine samples were collected. Urine Methanol levels were analyzed by paper and gas chromatography. Results: Mean concentration of Methanol in case group (1.2 micro mol/l) was significantly more than control group (0.78 micro mol/l). Also, Methanol level was significantly higher after work (1.45 micro mol/l) when compared to before work (1.27 micro mol/l), (P<0.05). No relation between work history and urine Methanol level was observed. Conclusion: Due to significant increase of Methanol concentration during work in work place, the use of protective methods such as suitable ventilation, wearing mask and gloves, also, using vapor absorbing tubes can be useful in increasing dental laboratory workplace safety.