Histological and Genotoxic Biomarkers in <Emphasis Type="Italic">Prochilodus lacustris</Emphasis> (Pisces,Prochilodontidae) for Environmental Assessment in a Protected Area in the Northeast of Brazil

The quality of aquatic environments all around the world is being altered by different human activities that represent direct threat to the ecological system and the aquatic biota. This study aimed to evaluate the occurrence of histological and genotoxic alterations in Prochilodus lacustris as indicators of anthropic impacts in a lacustrine environment in northeast Brazil. The histological alterations were evaluated using the histological alteration index, and the genotoxic alterations were detected using the micronuclei test, at three sampling stations (S1, S2 and S3). The gills presented lesions with three stages of severity, with mild lesions more frequent in the specimens collected at station S1. Mild hepatic tissue lesions were the most frequent type in both areas. Micronucleus analysis showed that station S3 was the most affected. The biological responses observed indicated that the fish are under influence of environmental changes. It is important to highlight that the organisms collected at station S3 had a more compromised health status.     

Preoperative dental anxiety and mood changes during nitrous oxide inhalation.

BACKGROUND: An estimated 35 million Americans experience significant apprehension about dental procedures, while an additional 10 to 12 million are considered to be "dental phobic" and avoid needed dental care altogether. Nitrous oxide is a general anesthetic used at subanesthetic concentrations to reduce anxiety during dental procedures. The purpose of this study was to characterize mood changes during nitrous oxide inhalation in patients with different levels of preoperative dental anxiety. METHODS: Forty-six patients who were to receive nitrous oxide during a dental procedure completed two anxiety scales. These patients were categorized into three groups: low anxiety, or LA, moderate anxiety, or MA, and high anxiety, or HA. They completed a visual analog scale of subjective effects before, during and after the dental procedure. RESULTS: A number of visual analog ratings, the majority of which could be considered pleasant, increased during nitrous oxide administration. It is significant that this increase in pleasant mood occurred in the HA and MA groups to the same degree as it did in the LA group. Patients in the HA and MA groups had elevated preoperative visual analog ratings of "anxious" that were reduced during nitrous oxide administration to a level equivalent to that reported by patients who had low preoperative anxiety. Patients in the HA group also had elevated preoperative visual analog ratings of "having unpleasant thoughts" and "feel bad" compared with the LA group. These ratings were reduced in the HA group to a level equivalent to that reported by patients in the LA group. CONCLUSIONS AND CLINICAL IMPLICATIONS: Regardless of their preoperative anxiety level, patients experienced a number of mood-altering effects during nitrous oxide inhalation, the majority of which could be considered pleasant. Ratings of an unpleasant nature decreased markedly in patients with high anxiety. These findings suggest that nitrous oxide may be an effective therapy in reducing patient anxiety during dental procedures.     

Tooth agenesis and craniofacial morphology in an orthodontic population.

Previous reports have produced conflicting conclusions regarding the relationship among tooth agenesis, the congenital absence of teeth, and variations in craniofacial morphology. Traditional cephalometric assessment and computer-assisted morphometric analysis of jaw size were used to reexamine this relationship in a white orthodontic population. A positive diagnosis of tooth agenesis (including third molar determination) was made in 89 subjects of mixed age and sex who previously had orthodontic treatment but who were not determined to have a recognized syndrome or a craniofacial anomaly. Cephalograms for these subjects were compared with control data from subjects reported in Bolton Standards of Dentofacial Developmental Growth. Missing teeth and their locations were correlated with changes in selected linear and angular measurements of the Bolton cephalometric analysis. Area measurements of the jaw size of the subjects grouped by age were compared with Bolton cephalometric templates. Relatively little correlation was found between missing teeth and changes in cephalometric measurements. Where identified, a decreased maxillary jaw size and maxillary tooth agenesis were generally associated. Two-dimensional area measurements showed that most age groups had significant decreases in maxillary jaw size associated with tooth agenesis. Relatively few groups had significant changes in mandibular size associated with tooth agenesis.     

Periodontal Attachment Loss in Independently Living Older Adults in Ontario, Canada

This paper describes the periodontal disease experience of a community-dwelling population aged 50 years and older, living in four communities in Ontario, Canada. The periodontal status of this population was assessed using attachment loss and the extent and severity index. Attachment loss was measured at two sites on each tooth using a pressure-sensitive periodontal probe. Complete periodontal data were obtained on 624 subjects. The mean number of sites per subject was 37.9. In line with recent US studies, the diagnostic threshold for a diseased or previously diseased site was set at 2 mm of loss. The overall mean attachment loss was 2.95 mm, with 19.7 percent of subjects having an overall mean attachment loss of 4.00 mm or more. The proportion of sites examined with loss of attachment of 2 mm or more was 77 percent. The severity of disease, defined as the average distance between the base of the sulcus or pocket and a point 1.00 mm apical to the cemento-enamel junction in sites with loss of 2 mm or more was 2.44 mm. These data indicate that the extent and severity of disease in this population were greater than that reported by some recent studies in the US. Taken together, the results of these studies suggest that there is some variation in the periodontal disease experience of population subgroups across North America.     

Root canal systems in mandibular first premolars with C-shaped root configurations. Part I: Microcomputed tomography mapping of the radicular groove and associated root canal cross-sections

The purpose of this study was to investigate the morphology of the radicular grooves and root canal cross-sections in mandibular first premolars that exhibit a C-shaped root. Eighty-six mandibular first premolars with C-shaped roots were scanned from the coronal to anatomical apex using microCT80. The location, length, and depth of the radicular grooves were measured. The cross-sectional morphology of root canal systems was evaluated at 11 levels. Results were subject to the Kruskal-Wallis test. Of the 86 C-shaped roots, a total of 93 radicular grooves were noted. Most of the grooves (78.5%) were located on the mesiolingual surface of the root. The C-shaped canal could vary considerably in shape at different levels, and the incidence of two canals at the middle and apical was 21% and 80%, respectively. This study shows that radicular grooves may present relevant morphologic variations in the root canal system when the C-shaped root is present.