A Comparative Study of ProTaper Universal and ProTaper Next Used by Undergraduate Students to Prepare Root Canals.

INTRODUCTION: The purpose of this study was to determine whether final-year undergraduate dental students achieved better shaping outcomes using the new ProTaper Next (PTN; Dentsply Sirona, Ballaigues, Switzerland) system to prepare root canals for the first time compared with the existing ProTaper Universal (PTU, Dentsply Sirona) system on which they had trained. A secondary aim was to explore the attitudes and preferences of the students toward both systems. METHODS: Forty students prepared 1 simulated S-shaped canal using PTN and another with PTU. Images of the canals were saved before and after preparation, and the outcomes assessed included the formation of aberrations and the amount of resin removed at specific points along the canal length. Student opinions relating to PTN and PTU were collected via a questionnaire completed immediately after using the systems. For statistical analysis, the McNemar test was used to compare the incidence of aberrations, and a paired t test was used to analyze the width measurements. Responses to the questionnaire were analyzed using frequencies. Thus, the McNemar test was used for paired binary data and the marginal homogeneity test for categoric data when more than 2 categories were used. Finally, the overall preferences (either PTN or PTU) were analyzed using the sign/binomial test, which is a standard statistical test that allows us to determine if the proportion preferring one or the other is equal or not. RESULTS: Canal ledges were formed in 30% of the canals prepared with PTU, whereas no ledges were formed with PTN (P < .001). A middle constriction, a form of canal aberration, was created by both systems although it occurred significantly (P = .006) more often with PTN. The "number of files" was judged by students to be significantly higher (P < .001) for PTU compared with PTN. Even though using PTN for the first time, students were more likely to recommend the system to other students for preparing S-shaped canals than PTU (P = .018) and preferred to use PTN in the future (P < .001). CONCLUSIONS: The students who had previous experience with the use of PTU were able to produce comparable shaping outcomes when they used PTN for the first time. For the preparation of S-shaped canals, the students preferred PTN over PTU in terms of the number of files and would prefer to use it in the future.

An on-line spectrophotometric determination of trace amounts of thiourea in tap water, orange juice, and orange peel samples using multi-channel flow injection analysis.

In this work, a flow injection analysis (FIA) method was introduced for the determination of trace amounts of thiourea in tap water. This method is based upon the inhibition effect of thiourea on the reaction between meta-cresol purple (MCP) and potassium bromate catalyzed by bromide ions in a sulfuric acid medium. In the presence of thiourea, an induction period appears in the reaction system, and as a result, the absorbance of MCP increases at 525 nm in the FIA manifold. The chemical and FIA variables are studied and optimized using the univariate and Simplex optimization methods. Under the optimum conditions, thiourea can be determined in the range of 0.100-13.0 µg mL(-1). The limit of detection (3σ) for thiourea was found to be 0.0310 µg mL(-1). The relative standard deviations (RSDs) for six replicate determinations of 0.500, 5.00, and 12.0 µg mL(-1) of thiourea were 4.0%, 1.8%, and 1.2%, respectively. The proposed method was also applied for the determination of thiourea in orange juice and orange peel samples with recoveries in the range of 98.0-101%. The analytical speed of the method was calculated to be about 120 sample per hour.

Malignancy in solitary solid cold thyroid nodule.

Solitary thyroid nodule is a common endocrine problem. The main concern of solitary thyroid nodule lies in excluding the malignancy & to operate on as few patients as possible. Other than history & clinical examination, hormone assessment, USG of thyroid gland, radionuclide scan & FNAC were used to differentiate malignant nodules from benign ones. In this study 127 cases with solitary thyroid nodule of all age group & both sexes were included from Endocrine & Thyroid clinic of BSMMU. They were clinically & biochemically euthyroid & had cold nodule on radionuclide scan. USG & FNAC were done & subsequently they underwent surgical procedure. On the basis of postoperative histopathological report the specimens were divided into benign & malignant groups. All the nodules were cold among which 104 were solid & 23 were mixed in consistency. Of the 104 solid cold nodules histopathology revealed 36(34.6%) malignant & 68(65.4%) benign cases. From the 23 mixed cold solitary nodule 5(21.7%) appeared malignant & 18(78.3%) were benign. So malignancy was higher in solid cold group than the mixed cold one but this was not statistically significant (p=0.673). FNAC was done & it revealed that 83(65.5%) cases were benign, 10(7.8%) cases were suspicious & 34(26.7%) were malignant. Finally histopathology showed 41(32.3%) cases were positive & 86(67.7%) cases were negative for malignancy.

Effect of fruits of Moringa oleifera on the lipid profile of normal and hypercholesterolaemic rabbits.

Rabbits were fed Moringa oleifera (200mg/kg/day, p.o.) or lovastatin (6mg/kg/day, p.o.) in banana pulp along with standard laboratory diet and hypercholesterolaemic diet for 120 days. Moringa oleifera and lovastatin were found to lower the serum cholesterol, phospholipid, triglyceride, VLDL, LDL, cholesterol to phospholipid ratio and atherogenic index, but were found to increase the HDL ratio (HDL/HDL-total cholesterol) as compared to the corresponding control groups. Treatment with M. oleifera or lovastatin in normal rabbits decreased the HDL levels. However, HDL levels were significantly increased or decreased in M. oleifera- or lovastatin-treated hypercholesterolaemic rabbits, respectively. Lovastatin- or M. oleifera-treated hypercholesterolaemic rabbits showed decrease in lipid profile of liver, heart and aorta while similar treatment of normal animals did not produce significant reduction in heart. Moringa oleifera was found to increase the excretion of faecal cholesterol. Thus, the study demonstrates that M. oleifera possesses a hypolipidaemic effect.

A comparison of three methods for detecting the acrosome reaction in human spermatozoa.

This study was designed to compare three different fluorescent probes to assay the acrosome reaction in human spermatozoa: chlortetracycline (CTC), mannosylated bovine serum albumin (BSA) labelled with fluorescein (MAF), and quinacrine (QN). Normal human sperm ejaculates were washed and allowed to swim up for 30-60 min. Samples were examined under epifluorescence for the percentage of the acrosome reacted spermatozoa, as detected by the three probes. There was no significant differences between samples of fresh, uncapacitated spermatozoa evaluated with CTC, MAF or QN; all gave < 10% reacted. Following capacitation for 3 h, the percentage of spontaneously reacted spermatozoa was higher than in fresh spermatozoa; CTC and MAF gave the same percentage (12%), while QN indicated a higher percentage (18%) of reacted spermatozoa (P < 0.001). Following exposure to ionophore A23187 at 1 h, the percentage of acrosome reactions increased to a mean of 31% as detected with CTC or MAF; the mean percentage (45%) was significantly higher with QN (P < 0.0001). Further incubation up to 2 h with A23187 did not change these percentages. These results suggest that the QN probe detects the onset stage of the acrosome reaction, whereas the CTC and MAF probes detect the later stages in which the acrosomal cap is lost. Use of the two types of probe provides a means for finer resolution of the time course of the acrosome reaction in the human spermatozoa.