Comparative analysis of optical microscopy, scanning electron microscopy, and micro-computed tomography on measurements

Abstract: Microscopic measurements are widely used in scientific research and the correct equipment to perform these evaluations could be critical to determine study results. Regarding microscopic measurements, three of the most used methods are: Optical Microscopy (OM), Scanning Electron Microscopy (SEM), and Micro-computed Tomography (MCT). It is important to select the best method for assessing diverse parameters, considering operational characteristics of the method, the equipment efficiency, and the machinery cost. Aim: Therefore, the main objective of this study was to define which is the most useful measurement method for assessing magnitudes below 0.4 mm. Methods: Ten dental implants, with known dimensions as defined by the manufacturer were randomly distributed. Two blinded observers assessed the distance between the second and the third screw vortex of the implants using three suggested methods. The true distance was defined to be 0.5 mm. Results: The assessed distances were: 0.597±0.007mm for OM, 0.578±0.017mm for SEM, and 0.613±0.006mm for MCT. The assessed distances were significantly different when the methods were compared (P>0.01). All measurements were into the CAD tolerances. Conclusion: It was possible to conclude that linear easurements between 595 and 605 µm could be performed by any of the described technologies (AU)

Influence of dentistry procedures on masticatory function of dentate patients

Aim: Evaluate the masticatory performance in patients with different clinical situations: patients with natural dentition without restorative and/or orthodontic intervention (Group CG) and patients with restorations and/or orthodontic intervention (Group TG). Subjects received instruction before the experiment, related to masticatory movements. Methods: Three capsules containing the granules were delivered separately to chew for 20 seconds each, controlled by the examiner. One capsule was chewed for 20 seconds only on the left side; the second capsule was chewed for 20 seconds only on the right side; and the third capsule was chewed for 20 seconds to simulate each patient's mastication. The mean data and standard deviation of masticatory function of each patient was calculated. Results: The results obtained in this study showed that there were no statistically significant differences (P < 0.05) between both tested groups (0.0320 ± 0.00716, 0.0436 ± 0.00974). Conclusions: Patients who were submitted to orthodontic and/or restorative procedures, with balanced occlusion could be used as a control group, making easier the patient recruitment. Clinicians and researchers on masticatory performance evaluation could apply the colorimetric method. The colorimetric method was a standardize method, effective and easy to execute. (AU)