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Eleven children, each having one or two pairs of premolars to be extracted for orthodontic purposes, participated in the study. The model involved placement of a special orthodontic band that allowed the accumulation of plaque in a defined area between the band and the buccal enamel. Examination of enamel changes was carried out in experimental teeth that had been exposed to local plaque accumulation for one, two, four, eight, or 14 days. The specimens were examined under the light (LM) and the scanning electron microscope (SEM). All teeth had signs of very mild dental fluorosis. No indications of demineralization were noted after one day. SEM examination showed signs of crystal dissolution in some of the two-day specimens. Six of eight four-day specimens exhibited surface dissolution. All eight- and 14-day specimens showed signs of surface demineralization in the LM as well as in the SEM. These observations documented that undisturbed bacterial deposits are capable of initiating enamel demineralization within short time periods, even in children living in a water-fluoridated area.

Plasma luteinizing hormone (LH) and testosterone (T) were measured by radioimmunoassay in 9 pubertal boys and 9 sexually mature adult men at 20 min intervals for 24 h. Polygraphic monitoring of sleep was also carried out to precisely identify sleep onset, wakefulness and specific sleep stages. In all 9 pubertal boys, plasma LH showed the characteristic augmentation of secretion synchronous with sleep. This increased LH secretory activity was effective in stimulating increased T secretion during sleep that resulted in uniformly higher mean T concentrations during sleep compared with waking. Plasma LH and T were also measured in 3 of these pubertal boys during acute inversion of the sleep wake cycle. The results showed that plasma LH and T were now augmented during the reversed daytime sleep period; the mean LH and T concentrations were significantly higher than during nocturnal waking. Measurement of LH and T in the 9 adult men showed episodic secretion of both hormones during waking and sleep periods with no consistent augmentation of either hormone during sleep.

Radiographically diagnosed incipient approximal carious lesions in deciduous molar teeth and control sites were sampled microbiologically at 6- or 12-week intervals for at least 12 months. Microbiolog

Thirty-four caries-free teeth destined for orthodontic extraction were banded to provide a protected area for the accumulation of plaque. The teeth were extracted at one, two, four, eight, and 14 days after being banded, and samples of the flora below the band were analyzed for the presence of Streptococcus sanguis, Streptococcus 'mitior', 'mutans streptococci', Actinomyces viscosus, Actinomyces naeslundii, Actinomyces odontolyticus, Lactobacillus species, and Veillonella. After plaque sampling, the teeth were sent to the Royal Dental College (Copenhagen) for histological analysis. The results showed that S. mutans could colonize the area below the band after one day, but that colonization was only 100% at 14 days. Lactobacillus was only isolated from 2/8 samples at four days and from 4/8 samples at 14 days. S. sanguis and 'S. mitior' were regularly isolated at all banding times, and Veillonella was isolated from all samples. A. viscosus was the most commonly isolated Actinomyces. The numbers of Streptococcus and Veillonella were significantly higher at day 1 than at day 14 (p < 0.05). S. mutans and A. viscosus were isolated more frequently at day 14 than at day 1 (p < 0.01). Histological examination revealed that dissolution of the enamel below a band could occur after two days, but that even after 14 days dissolution could be questionable. Dissolution was detected in areas where S. mutans was not isolated (8/34), but S. mutans was also present in samples showing dissolution (12/34). There was no relationship between dissolution and the numbers of S. mutans; however, the isolation frequency of S. mutans was associated with dissolution (p < 0.05). The results also suggested that there were subject-associated factors that influenced the composition of the bacterial community, as evidenced by Lactobacillus being isolated from all samples from one subject after 14 days, while the other subject was negative for Lactobacillus.

Plasma luteinizing hormone (LH) and testosterone (T) were measured by radioimmunoassay in 9 pubertal boys and 9 sexually mature adult men at 20 min intervals for 24 h. Polygraphic monitoring of sleep was also carried out to precisely identify sleep onset, wakefulness and specific sleep stages. In all 9 pubertal boys, plasma LH showed the characteristic augmentation of secretion synchronous with sleep. This increased LH secretory activity was effective in stimulating increased T secretion during sleep that resulted in uniformly higher mean T concentrations during sleep compared with waking. Plasma LH and T were also measured in 3 of these pubertal boys during acute inversion of the sleep wake cycle. The results showed that plasma LH and T were now augmented during the reversed daytime sleep period; the mean LH and T concentrations were significantly higher than during nocturnal waking. Measurement of LH and T in the 9 adult men showed episodic secretion of both hormones during waking and sleep periods with no consistent augmentation of either hormone during sleep.