Adhesive temperature: effects on adhesive properties and resin-dentin bond strength.

OBJECTIVES: To evaluate the effect of adhesive temperature on the resin-dentin bond strength (µTBS), nanoleakage (NL), adhesive layer thickness (AL), and degree of conversion (DC) of ethanol/water- (SB) and acetone-based (PB) etch-and-rinse adhesive systems. METHODS: The bottles of the two adhesives were kept at each temperature (5°C, 20°C, 37°C, and 50°C) for 2 hours before application to demineralized dentin surfaces of 40 molars. Specimens were prepared for µTBS testing. Bonded sticks (0.8 mm(2)) were tested under tension (0.5 mm/min). Three bonded sticks from each tooth were immersed in silver nitrate and analyzed by scanning electron microscopy. The DC of the adhesives was evaluated by Fourier transformed infrared spectroscopy. RESULTS: Lower µTBS was observed for PB at 50°C. For SB, the µTBS values were similar for all temperatures. DC was higher at 50°C for PB. Higher NL and thicker AL were observed for both adhesives in the 5°C and 20°C groups compared to the 37°C and 50°C groups. The higher temperatures (37°C or 50°C) reduced the number of pores within the adhesive layer of both adhesive systems. CONCLUSIONS: It could be useful to use an ethanol/water-based adhesive at 37°C or 50°C and an acetone-based adhesive at 37°C to improve adhesive performance.

Evaluation of the effectiveness of peracetic acid in the sterilization of dental equipment.

PURPOSE: To evaluate the effectiveness of peracetic acid in the microbiological sterilisation of dental materials. METHODS: Peracetic acid solution was evaluated at concentrations of 800, 1500 and 2500 ppm. At these concentrations, it was determined whether peracetic acid caused corrosion to dental instruments and induced cellular mutagenicity and cytotoxicity. In addition, the minimum inhibitory concentration (MIC), the minimum bactericidal concentration (MBC), agar diffusion and diffusion by well method, were also verified. RESULTS: The corrosion rate, calculated from potentiodynamic assays was 10(-6) cm/year, indicating that the product does not damage equipment. The sterilisation capacity of peracetic acid at 2500 ppm was the best. The comet assay indicated genotoxic activity at 2500 ppm. CONCLUSIONS: This study demonstrated the effectiveness of peracetic acid for sterilizing dental equipment, providing another alternative for the prevention of infections in clinics.

Determination of charge states of single swift heavy projectiles by high-energy delta-electrons.

The effective charge state is an important particle parameter which is required for the calculation of many effects concerning the interaction between radiation and matter such as an estimate of the radial dose of swift heavy projectiles, stopping power and so on. A new method for the determination of effective charge states of heavy ions is based on the measurement of the number of high-energy delta-electrons which are ejected from a target by the penetrating ion. These electrons are detectable with a CCD-detector and their number can be correlated to the effective charge state of the projectile for known particle velocities. This method is even applicable to operation with single swift heavy ions within statistical bounds.

The development of auditory event related potentials in the rhesus monkey (Macaca mulatta).

Auditory event related potentials were recorded from neonatal, 3-month, and 3-year old rhesus monkeys. Auditory brainstem evoked responses (ABRs) were reliably recorded at all ages. ABR latencies decreased with age. Age effects were greater the more centrally generated the wave. Wave I amplitude decreased with age, Wave II increased, and Wave IV remained about the same. Stimulus rate effects were greater in neonates than older monkeys. Stimulus frequency also affected the ABR, but not differentially as a function of age. Recording montage had a significant effect on the recorded waveform. Wave I tended to be larger in amplitude in horizontal recordings and front-back recordings, while the later waves were relatively more prominent in more vertical montages. Middle latency evoked responses and late potentials were less reliably recorded than the ABR. Their reproducibility improved with age. Auditory event related potentials are promising measures of auditory function for research requiring nonhuman primate models of the developing human.

The changing image of Catholic women.

The characteristics of Roman Catholic women in today's society were investigated. Subjects were 154 Catholic women, both religious and lay, who participated on a volunteer basis. The Catholic lay women (111) were divided into two groups: those who attended a Catholic elementary school (63) and those who attended a non-Catholic elementary school (48). Catholic women religious were found to be more dominant and independent minded than in previous research. All of the women studied were found to be more aggressive and more critical of authority than in previous studies. Likewise, Catholic women no longer see themselves in the role of nurturers.