Unfavorable cephalometric changes resulting immediately after RME are temporary, and therefore concerns about using RME in patients with vertical growth patterns or an extremely convex facial profile are not substantiated.

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ObjectiveThe aim of the present study was to verify the torque precision of metallic brackets with MBT prescription using the canine brackets as the representative sample of six commercial brands. Material and MethodsTwenty maxillary and 20 mandibular canine brackets of one of the following commercial brands were selected: 3M Unitek, Abzil, American Orthodontics, TP Orthodontics, Morelli and Ortho Organizers. The torque angle, established by reference points and lines, was measured by an operator using an optical microscope coupled to a computer. The values were compared to those established by the MBT prescription. ResultsThe results showed that for the maxillary canine brackets, only the Morelli torque (-3.33º) presented statistically significant difference from the proposed values (-7º). For the mandibular canines, American Orthodontics (-6.34º) and Ortho Organizers (-6.25º) presented statistically significant differences from the standards (-6º). Comparing the brands, Morelli presented statistically significant differences in comparison with all the other brands for maxillary canine brackets. For the mandibular canine brackets, there was no statistically significant difference between the brands. ConclusionsThere are significant variations in torque values of some of the brackets assessed, which would clinically compromise the buccolingual positioning of the tooth at the end of orthodontic treatment.

Effective orthodontic anchorage may be obtained by miniimplants inserted into the maxillary bones. However, the risk of miniimplant failure is one of the most important issues, especially the rupture of its structure referred to as fracture, mainly due to metal deficiencies. This study analyzed the internal microstructure of orthodontic mini-implants, ascertaining the composition of the metal to detect possible discontinuities from the surface to the core of the screws. Eighteen samples of mini-implants, of 3 different brands, were obtained. The samples were cold-embedded in methyl methacrylate polymer, and were sectioned both longitudinally (3 samples of each brand) and transversely (the other 3 screws of each brand). After preparation, the samples were observed using a light microscope at up to 2,000 x magnification. The results showed that the mini-implants thus analyzed were composed of an Alpha-Beta globular phase of titanium alloy, patterns A1 and A9 (in accordance with the "Technical Committee of European Titanium Producers"). The miniimplants did not present any defects such as bubbles, imperfections or fissures, in either longitudinal or transverse sections, in their internal microstructure. All samples met the requirements of international norms. Orthodontists must be aware of the metal composition and internal microstructure of mini-implants, to decrease the risk of fractures.

Aim: This experimental study investigated the association between masticatory hypofunction and mandibular morphological dimensions and internal bone characteristics. Methods: Twentyfour 21-day-old male Wistar rats were randomly divided into two groups, according to the diet consistency. The control group (CG) was fed a solid diet (pellets) and the experimental group (EG) received a powdered diet during 50 days. All animals were euthanized and their mandibles removed and processed for histomorphometric analysis. A calibrated examiner performed linear and angular measurements (mandibular body length and height, mandibular lengths, ramus depth and height, mandibular base depth, mandibular head and gonial angle) on photographs, estimated bone density in the mandibular ramus region on digital radiographs and assessed the area of cortical and trabecular bone tissue in the second molar region, in 5-µm-thick serial cuts stained with Cason's Trichrome. Measurements for the study groups were compared using Mann-Whitney test (α=0.05). Results: some of the macroscopic dimensions evaluated on photographs were significantly smaller in EG compared to CG, specifically mandibular ramus height (10.77 mm vs. 11.11 mm, p=0.0375), mandibular body length (21.67 mm vs. 22.36 mm, p=0.0165) and height (4.24 mm vs. 4.54 mm, p=0.0016), as well as mandibular base depth (1.24 mm vs. 1.47 mm, p=0.0325). The relative mineral bone density was significantly decreased in EG (1.04) compared to CG (1.25), p<0.001. Rats in the EG also presented smaller trabecular and cortical bone area (2.36 mm²) than those in CG (3.16 mm²), p<0.001. Conclusions: Based on the above-mentioned measurements, it may be concluded that masticatory hypofunction induced by a powdered diet affected mandibular morphology and was associated with significantly reduced bone content.