X-ray fluorescence with synchrotron radiation to elemental analysis of lead and calcium content of primary teeth

Primary teeth were analyzed by micro-SRXRF. The aim of this study was to determine the elemental distribution of lead and calcium in different regions of primary incisor of children living in a notoriously contaminated area (Santo Amaro da Purificacao, Bahia State, Brazil). The measurements were performed in standard geometry of 45 incidence, exciting with a white beam and using a conventional system collimation (orthogonal slits) in the XRF beamline at the Synchrotron Light National Laboratory (Campinas, Brazil). (C) 2009 Elsevier Ltd. All rights reserved.

Masticatory process in individuals with maxillary and mandibular osteoporosis: electromyographic analysis

The masseter and temporal muscles of patients with maxillary and mandibular osteoporosis were submitted to electromyographic analysis and compared with a control group. In conclusion, individuals with osteoporosis did not show significantly lower masticatory cycle performance and efficiency compared to the control group during the proposal mastications. This study aimed to examine electromyographically the masseter and temporal muscles of patients with maxillary and mandibular osteoporosis and compare these patients with control patients. Sixty individuals of both genders with an average age of 53.0 +/- 5 years took part in the study, distributed in two groups with 30 individuals each: (1) individuals with osteoporosis; (2) control patients during the habitual and non-habitual mastication. The electromyographic apparel used was a Myosystem-BR1-DataHomins Technology Ltda., with five channels of acquisition and electrodes active differentials. Statistical analysis of the results was performed using SPSS version 15.0 (Chicago, IL, USA). The result of the Student`s t test indicated no significant differences (p > 0.05) between the normalized values of the ensemble average obtained in masticatory cycles in both groups. Based on the results of this study, it was concluded that individuals with osteoporosis did not show significantly lower masticatory cycle performance and efficiency compared to control subjects during the habitual and non-habitual mastications. This result is very important because it demonstrates the functionality of the complex physiological process of mastication in individuals with osteoporosis at the bones that compose the face.

Morphodigital study of bone quality in the mandibular angle in patients with third molar impacted

The aim of this study was to analyze if the presence of impacted third molars, and their positions in the mandibular angle, can change the bone quality in this area, considering the measure of the cortical thickness in this region as representative or not for mandible fracture risk. Software was used to analyze 50 digital images from panoramic radiographs of patients who had one or two impacted third molars in the mandible, and 30 digital images of patients with agenesis of the mandibular third molar. The thickness of the cortical region of the mandible was measured; it was possible to draw a parallel line to the posterior portion of the mandible and a parallel line to the body of this bone on each side of the image. At the intersection of these lines near the distal portion of the second molar, another line was set up to serve as reference in the cortical thickness measurement. It could be concluded that the cortical thickness of the mandibular angle in male patients without impacted third molars was greater than the thickness in patients with these teeth, and no difference in thickness was found for the female group.

Analysis of enamel microbiopsies in shed primary teeth by Scanning Electron Microscopy (SEM) and Polarizing Microscopy (PM)

The aims of this study were 1) to verify how close to the theoretically presumed areas are the areas of enamel microbiopsies carried out in vivo or in exfoliated teeth; 2) to test whether the etching solution penetrates beyond the tape borders: 3) to test whether the etching solution demineralizes the enamel in depth. 24 shed upper primary central incisors were randomly divided into two groups: the Rehydrated Teeth Group and the Dry Teeth Group. An enamel microbiopsy was performed, and the enamel microbiopsies were then analyzed by Scanning Electron Microscopy (SEMI) and Polarizing Microscopy (PM). Quantitative birefringence measurements were performed. The ""true"" etched area was determined by measuring the etched enamel using the NIH Image analysis program. Enamel birefringence was compared using the paired t test. There was a statistically significant difference when the etched areas in the Rehydrated teeth were compared with those of the Dry teeth (p = 0.04). The etched areas varied from -11.6% to 73.5% of the presumed area in the Rehydrated teeth, and from 6.6% to 61.3% in the Dry teeth. The mean percentage of variation in each group could be used as a correction factor for the etched area. Analysis of PM pictures shows no evidence of in-depth enamel demineralization by the etching solution. No statistically significant differences in enamel birefringence were observed between values underneath and outside the microbiopsy area in the same tooth, showing that no mineral loss occurred below the enamel superficial layer. Our data showed no evidence of in-depth enamel demineralization by the etching solution used in the enamel microbiopsy proposed for primary enamel. This study also showed a variation in the measured diameter of the enamel microbiopsy in nineteen teeth out of twenty four, indicating that in most cases the etching solution penetrated beyond the tape borders. (C) 2009 Elsevier B.V. All rights reserved.

Radiographic Signals Detection of Systemic Disease. Orthopantomographic Radiography

For the purposes of this report, ""systemic disease"" will be interpreted as conditions that are spread out within the body rather than localized strictly to the tissues of the oral cavity. Since it would take many volumes to review all such conditions, the intent of the authors is to review a few examples of conditions where initial panoramic radiographic findings suggested widespread disease of significance enough to affect the quality of life and longevity of the patient.

Bone repair in mandibular body osteotomy after using 2.0 miniplate system - histological and histometric analysis in dogs

The objective of this study was to evaluate the bone repair along a mandibular body osteotomy after using a 2.0 miniplate system. Nine adult mongrel dogs were subjected to unilateral continuous defect through an osteotomy between the mandibular 3rd and 4th premolars. Two four-hole miniplates were placed in accordance with the Arbeitgeimeinschaft fur Osteosynthesefragen Manual. Miniplates adapted to the alveolar processes were fixed monocortically with 6.0-mm-length titanium alloy self-tapping screws, whereas miniplates placed near the mandible bases were fixed bicortically. At 2, 6 and 12 weeks, three dogs were sacrificed per period, and the osteotomy sites were removed, divided into three thirds (Tension Third, TT; Intermediary Third, IT; Compression Third, CT) and prepared for conventional and polarized light microscopy. At 6 weeks, while the CT repaired faster and showed bone union by woven bone formation, the TT and IT exhibited a ligament-like fibrous connective tissue inserted in, and connecting, newly formed woven bone overlying the parent lamellar bone edges. At 12 weeks, bone repair took place at all thirds. Histometrically, proportions of newly formed bone did not alter at TT, IT and CT, whereas significantly enhanced bone formation was observed for the 12-week group, irrespective of the third. The results demonstrated that although the method used to stabilize the mandibular osteotomy allowed bone repair to occur, differences in the dynamics of bone healing may take place along the osteotomy site, depending on the action of tension and compression forces generated by masticatory muscles.

The use and abuse of population viability analysis

A recent study by Brook ef al. empirically tested the performance of population viability analysis (PVA) using data from 21 populations across a wide range of species. The study concluded that PVAs are good at predicting the future dynamics of populations. We suggest that this conclusion is a result of a bias in the studies that Brook et al, included in their analyses, We present arguments that PVAs can only be accurate at predicting extinction probabilities if data are extensive and reliable, and if the distribution of vital rates between individuals and years can be assumed stationary in the future, or if any changes can be accurately predicted. In particular, we note th at although catastrophes are likely to have precipitated many extinctions, estimates of the probability of catastrophes are unreliable.