Evaluation of the effect of high-intensity light-curing device on micro-leakage of pits and fissure sealants

Reducing treatment time is one of the most important trends in modern dentistry. This study aimed to compare the micro-leakage around the resin sealants when using both high and conventional intensity light-curing systems. The study sample consisted of 30 extracted human maxillary premolar teeth that were divided into two equal groups according to the light-curing system used: Group 1, High-Intensity Light-Curing System and Group 2, Conventional Light-Curing System. Light-curing by Woodpecker I-LED device with two intensities (high and conventional) has been used. All teeth were subjected to 500 cycles of thermocycling. Then, a methylene blue dye microleakage test was performed, and the teeth were sectioned longitudinally and studied under a stereo microscope. The mean of micro-leakage in the high-intensity group (1.33 ± 1.29) was less than in the conventional intensity group (1.63 ± 1.29) without any statistically significant differences (p = 0.320). The high-intensity light-curing system mode may be a good and acceptable alternative to conventional intensity light-curing system mode in polymerization of pits and fissure sealants.

Antenatal corticosteroids in the late preterm period: A prospective cohort study

OBJECTIVE

The study objective was to examine the effect of antenatal corticosteroids on the incidence of short-term neonatal morbidities in singletons born during the late preterm period.

STUDY DESIGN

This was a prospective cohort study of singleton gestations at risk of imminent delivery between 34 0/7 and 36 6/7 weeks. Short-term neonatal morbidities were compared between the corticosteroid exposed and non-exposed groups. The rates of Neonatal Morbidity Composite and Any Adverse Neonatal Morbidity were then compared between the two groups.

RESULTS

During the two-year study period, a total of 295 subjects were included. Of those, 74 were exposed to antenatal corticosteroids, while 221 cases constituted the non-exposed group. There was no statistically significant difference in the rate of Any Adverse Neonatal Morbidity (47.3% vs. 40.7% , p = 0.32) or the rate of Neonatal Morbidity Composite (34.4% vs. 37.8% , p = 0.59) between the two groups. Additionally, there was no statistically significant difference in the rates of neonatal intensive care unit admission, respiratory distress syndrome, transient tachypnea of the newborn, hypothermia, and need for phototherapy.

CONCLUSION

Administration of antenatal corticosteroids to parturients at risk of imminent delivery during the late preterm period does not appear to reduce short-term neonatal morbidities.

Characterization of influenza outbreaks in Lebanon during the 2013/14 and 2014/15 seasons

Despite the significant burden of influenza outbreaks, active disease monitoring has been largely absent in the Middle East, including Lebanon. In this study we characterized influenza virus in 440 nasopharyngeal swabs collected from patients with acute respiratory infections during two influenza seasons in Lebanon. Influenza A(H3N2) was dominant in the 2013/14 season while the A(H1N1)pdm09 and B/Yamagata strains were most prevalent in the 2014/15 season. All tested isolates were susceptible to 4 neuraminidase inhibitors (oseltamivir, zanamivir, peramivir and laninamivir). Genetic analysis of the haemagglutinin gene revealed multiple introductions of influenza viruses into Lebanon from different geographic sources during each season. Additionally, large data gaps were identified in the Middle East region, as indicated by the lack of current influenza sequences in the database from many countries in the region.

Optimization of a metformin effervescent floating tablet containing hydroxypropylmethylcellulose and stearic acid

This study optimizes the composition of an effervescent floating tablet (EFT) containing metformin hydrochloride (M) regarding tablet hardness (H), time to dissolve 60% of the embedded drug (t60%), and buoyancy, the floating lag time (FLT). A simplex lattice experimental design has been used comprising different levels of hydroxypropylmethylcellulose (HPMC), stearic acid (SA), sodium bicarbonate (SB) as tablet matrix components, and hardness (H), t60%, FLT as response variables. Two models have been applied to decide which composition will result in Fickian diffusion or in overlapping of two dissolution mechanisms, diffusion and matrix erosion. Three of EFT showed the two dissolution mechanisms but most of EFT showed Fickian diffusion only. Checking the experimental response by a linear, quadratic, special cubic and cubic model using multivariate regression analysis resulted in best fit for the cubic model. Overlaying the results for the cubic model under constraints defined shows the domain of accepted values of response variables. The optimized EFT shall have been included HPMC between 15.6% and 24.2%, SA between 12.8 and 15.6% and SB between 16.1% and 17.5%. The result of this study has been critically evaluated considering analogous EFT described in literature.