Parental report of dental pain and discomfort in preschool children is associated with sleep disorders: a cross-sectional study in Brazilian families.

PURPOSE: To evaluate the prevalence of sleep disorders in Brazilian preschool children and its associations with parental report of dental pain and discomfort. METHODS: This cross-sectional study involved 604 Brazilian preschoolers (4-5 years old). Sleep disorders (SD) and the parental report of dental pain and discomfort (DPD) were evaluated using the Brazilian versions of the Sleep Disturbance Scale for Children (SDSC) and the Dental Discomfort Questionnaire (DDQ-B), respectively. Bivariate and multivariate Poisson regression analyses with robust variance were performed to analyze the association between SDSC and DP. RESULTS: Prevalence of SD ranged from 7 to 21%. 7.9% of the children had DPD indicating the need for more invasive dental procedures (DDQ-B ≥ 5). Significant associations were found between DPD and the following SDSC domains: sleep hyperhidrosis (p = 0.024; PRa = 1.38; 95% CI: 1.04-1.83), disorders of initiating and maintaining sleep (p < 0.001; PRa = 1.41; 95% CI: 1.15-1.73), parasomnias (p < 0.001; PRa = 1.82; 95% CI: 1.39-2.37), and sleep-wake transition disorders (p = 0.018; PRa = 1.28; 95% CI: 1.04-1.58). Children with higher prevalence of DPD presented 20% higher prevalence of SD than children lower prevalence of DPD (p = 0.039; PRa = 1.20; 95% CI: 1.01-1.44). CONCLUSION: Preschool children with higher prevalence of DPD are more likely to have SD, such as hyperhidrosis, disorders of initiating and maintaining sleep, parasomnias, and sleep-wake transition.

Agonistic Behavior Is Affected by Memory in the Dusky Damselfish Stegastes fuscus.

The ability to discriminate familiar from unfamiliar conspecifics has been demonstrated in several species of fish. Agonistic interactions are among the most frequent behaviors exhibited by territorial species and could offer useful information for the individual recognition process. In agonistic situations, memory may modulate the behavioral response and affect social dynamics, but few studies have explored the memory retention acquired during aggressive encounters. The present study investigated the memory retention of an agonistic encounter in the dusky damselfish Stegastes fuscus. The experimental procedure was divided into three parts: (1) Familiarization; (2) Recognition test; and (3) Memory test. During the familiarization phase, the fish were visually exposed to the same conspecific for 5 days (10 min per day) and the behavior was recorded. On the following day (conspecific recognition test), half of the animals were paired with the same conspecific and the other half with a different conspecific for 10 min, and the behavior was recorded. The fish were retested 5, 10, and 15 days after the test to evaluate memory retention. In the memory test, they were exposed to the same conspecific as before or to a different conspecific. We found that the damselfish reduced their agonistic displays when the stimulus fish was familiar, but when it was unfamiliar, the animals were more aggressive and only reduced their mnemonic response after 10 days. These results suggest that the recognition ability of damselfish can be affected by time and that it modulates agonistic response.

Alendronate induces postnatal maxillary bone growth by stimulating intramembranous ossification and preventing premature cartilage mineralization in the midpalatal suture of newborn rats.

Cleft palate is a common malformation of craniofacial development, and postnatal deficiencies in palate formation may occur. The aim of this study was to determine whether alendronate treatment could induce maxillary mineralization and thus reduce the need for surgical procedures. The effects of alendronate on maxillary bone development, the midpalatal suture, and the levels of transforming growth factor beta-1 (TGF-ß1), bone morphogenetic protein 2 (BMP-2), collagen I and II, and V-ATPase were evaluated in newborn rats. Thirty newborn rats were placed in a control group and 30 in a group that received intraperitoneal alendronate (2.5 mg/kg/day). The animals were euthanized on day 7 or 12, and the heads were subjected to histological and immunohistochemical analyses. Specimens from rats that received alendronate presented larger bone matrix deposition in areas of intramembranous ossification of the maxillary bone when compared to controls. Furthermore, higher levels of TGF-ß1, BMP-2, and collagen I were observed, whereas osteoclasts showed no V-ATPase. The alendronate group also showed higher levels of TGF-ß1 and collagen II in the midpalatal suture, whereas BMP-2 levels were lower than in controls. These results coincided with an expansion of the chondroid. In conclusion, alendronate increased the intramembranous ossification in the maxillary bone in association with increased expression of TGF-ß1, BMP-2, and collagen I and decreased V-ATPase. The drug induced an expansion of chondrocytes and a decrease in mineral bone deposition despite the high levels of TGF-ß1 in this area. Alendronate may therefore be useful in the treatment of diseases affecting bone growth.