Reproducibility of electrical caries measurements: A technical problem?

The currently available instrument for electrical detection of occlusal caries lesions {[}Electronic Caries Monitor (ECM)] uses a site-specific measurement with co-axial air drying. The reproducibility of this method has been reported to be fair to good. It was noticed that the measurement variation of this technique appeared to be non-random. It was the aim of this study to analyse how such a non-random reproducibility pattern arises and whether it could be observed for other operators and ECM models. Analysis of hypothetical measurement pairs showed that the pattern was related to measurements at the high and low end of the measurement range for the instrument. Data sets supplied by other researchers to a varying degree showed signs of a similar non-random pattern. These data sets were acquired at different locations, by different operators and using 3 different ECM models. The frequency distribution of measurements in all cases showed a single or double end-peaked distribution shape. It was concluded that the pattern was a general feature of the measurement method. It was tentatively attributed to several characteristics such as a high value censoring, insufficient probe contact and unpredictable probe contact. A different measurement technique, with an improved probe contact, appears to be advisable. Copyright (C) 2005 S. Karger AG, Basel

Menstrual cycle phase and sexual arousability in women

__Abstract__ Sexual arousability of women has not been consistently found to vary significantly over phases of the menstrual cycle. We studied changes in the temperature of a labium minus and subjective sexual and genital arousal recorded on semantic scales while watching erotic video in 12 women with natural menstrual cycles and 12 women using low-dose estrogen oral contraceptive pills. Natural cycle phase was ascertained by blood progesterone. Subjects were tested twice, with an interval of about 2 weeks. Half of each group had their first test during their luteal phase, the others during their follicular phase. Women tested for the first time in their follicular phase were sexually more aroused than women tested for the first time during their luteal phase. This was true for both objective (i.e., a labium minus change in temperature) and subjective genital arousal. When these women were retested in their alternative phase of the menstrual cycle, those who were then follicular did not score higher than those who were then luteal. On the contrary, the latter group scored as high as when tested during their follicular phase. This phenomenon was observed both in women with and without oral contraception. The nature of the menstrual phase (i.e., natural or pill-induced) seems irrelevant in this respect. Sexual arousal achieved during the first session appeared to be correlated with an increase in desire for making love during the rest of the day and night. Only 1 of 12 women tested during their luteal phase indicated an increase in desire to make love, while 6 of 12 women tested during their follicular phase indicated an increase. Apparently the menstrual cycle phase during the first test determines the immediate response and indirectly affects the response during the second test approximately 10 days later. In a random block design the difference in sexual response between follicular and luteal phase of the menstrual cycle disappears

Very different performance of the power Doppler modalities of several ultrasound machines ascertained by a microvessel flow phantom

Introduction: In many patients with rheumatoid arthritis (RA) subclinical disease activity can be detected with ultrasound (US), especially using power Doppler US (PDUS). However, PDUS may be highly dependent on the type of machine. This could create problems both in clinical trials and in daily clinical practice. To clarify how the PDUS signal differs between machines we created a microvessel flow phantom.Methods: The flow phantom contained three microvessels (150, 1000, 2000 microns). A syringe pump was used to generate flows. Five US machines were used. Settings were optimised to assess the lowest detectable flow for each US machine.Results: The minimal detectable flow velocities showed very large differences between the machines. Only two of the machines may be able to detect the very low flows in the capillaries of inflamed joints. There was no clear relation with price. One of the lower-end machines actually performed best in all three vessel sizes.Conclusions: We created a flow phantom to test the sensitivity of US machines to very low flows in small vessels. The sensitivity of the power Doppler modalities of 5 different machines was very different. The differences found between the machines are probably caused by fundamental differences in processing of the PD signal or internal settings inaccessible to users. Machines considered for PDUS assessment of RA patients should be tested using a flow phantom similar to ours. Within studies, only a single machine type should be used

Regression of white spot enamel lesions:A new optical method for quantitative longitudinal evaluation in vivo

This article describes a new nondestructive optical method for evaluation of lesion regression in vivo. White spot caries lesions were induced with orthodontic bands in two vital premolars of seven patients. The teeth were banded for 4 weeks with special orthodontic bands that allowed plaque accumulation on the buccal surface. The teeth were left in the dentition for 2 or 4 weeks after debanding. Regular oral hygiene with a nonfluoridated toothpaste was applied during the entire experimental period. The optical scattering coefficient of the banded area was measured before banding and in 1-week intervals thereafter. The scattering coefficient returned to the sound value in an exponential manner, the half-value-time for left teeth being 1.1 week, for right teeth 1.8 weeks, these values being significantly inequal (p = 0.035). At the start of the regression period, the scattering coefficient of left teeth lesions was 2.5 as high as of right teeth lesions, values being inequal with p = 0.09. It is concluded that regression of initial lesions in the presence of saliva is a relatively rapid process. The new optical method may be of clinical importance for quantitative evaluation of enamel lesion regression developed during fixed appliance therapy