AIM: To evaluate the stress changes in the maxilla during fixed functional appliance use using three-dimensional finite element method (FEM) stress analysis. SETTINGS AND SAMPLE POPULATION: A three-dimensional finite element model of the maxilla was constructed using the images generated from the cone-beam computed tomography of a patient treated for Class II malocclusion with a fixed functional orthodontic appliance. The FEM was used to study the stress changes seen in the maxilla, which were evaluated in the form of highest von Mises stress and maximum principal stress before and after the application of fixed functional appliance. RESULTS: Higher areas of stress were seen in the model of the maxilla with the fixed functional appliance (140 MPa) compared to that in the resting stage (58.99 MPa). CONCLUSIONS: An increase in the maximum principal stress and von Mises stress in the posterior regions of the maxilla and maxillary teeth was seen. The stresses seen were double than that without the appliance. A high distalization force on the maxilla was seen with the fixed functional appliance.

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Aims: The present study was conducted for evaluation of salivary chromium levels among patients undergoing fixed orthodontic treatment. Materials & method: 20 patients who presented to the orthodontic clinic were selected. The salivary samples were taken from the patients in following stages: before appliance placement, one month, and 4 months following appliance placement. The salivary samples were collected in a plastic tube and were stored in the freezer before analysis. The samples were then transferred to the laboratory, and the amounts of metals were determined by graphite furnace atomic absorption spectrometry with an autosampler. Each sample was analyzed three times, and the average was reported. All the results were recorded and analysed by SPSS software. Results: Mean salivary chromium levels before appliance placement; one month after appliance placement and four months after appliance placement was 2.5 μg/L, 3.9 μg/L and 2.9 μg/L respectively. Significant results were obtained while comparing the alteration in salivary chromium levels. Significant results were obtained while comparing the salivary chromium levels at different time intervals. Conclusion: Corrosion of fixed orthodontic appliances leads to elevated salivary chromium levels early after the initiation of orthodontic treatment.