Temporomandibular disorders (TMD) comprise the most common cause of chronic facial pain conditions, and they are often associated with somatic and psychological complaints including fatigue, sleep disturbances, anxiety, and depression. For many health professionals, the subjectivity of pain experience is frequently neglected even when the clinic does not find any plausible biologic explanation for the pain. This strictly biomedical vision of pain cannot be justified scientifically. The purpose of this study is to demonstrate, by original articles from the literature and recent studies conducted in our own laboratory, the biological processes by which psychological stress can be translated into the sensation of pain and contribute to the development of TMD. The role of the hypothalamic-pituitary-adrenal axis, the serotoninergic and opioid systems in the pathogenesis of facial pain is exposed, including possible future therapeutic approaches. It is hoped that knowledge from apparently disparate fields of dentistry, integrated into a multidisciplinary clinical approach to TMD, will improve diagnosis and treatment for this condition through a clinical practice supported by scientific knowledge.

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The purpose of this study was to evaluate in vitro the shear bond strength of recycled orthodontic brackets. S2C-03Z brackets (Dental Morelli, Brazil) were bonded to the buccal surfaces of 50 extracted human premolars using Concise Orthodontic chemically cured composite resin (3M, USA). The teeth were randomly assigned to 5 groups (n=10), as follows. In group I (control), the bonded brackets remained attached until shear testing (i.e., no debonding/rebonding). In groups II, III and IV, the bonded brackets were detached and rebonded after recycling by 90-μm particle aluminum oxide blasting, silicon carbide stone grinding or an industrial process at a specialized contractor company (Abzil-Lancer, Brazil), respectively. In group V, the bonded brackets were removed and new brackets were bonded to the enamel surface. Shear bond strength was tested in an Instron machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. There was no statistically significant difference (p>0.05) between the control brackets (0.52 kgf/mm 2 ), brackets recycled by aluminum oxide blasting (0.34 kgf/mm 2 ) and new brackets attached to previously bonded teeth (0.43 kgf/mm 2 ). Brackets recycled by the specialized company (0.28 kgf/mm 2 ) and those recycled by silicon carbide stone grinding (0.14 kgf/mm 2 ) showed the lowest shear strength means and differed statistically from control brackets (0.52 kgf/ mm 2 ) (p<0.05). In conclusion, the outcomes of this study showed that bracket recycling using 90-μm aluminum oxide particle airabrasion was efficient and technically simple, and might provide cost reduction for orthodontists and patients alike.

Objective: To test the hypothesis that short-and long-term celecoxib administration has no effect on orthodontic tooth movement. Materials and Methods: Male Wistar rats were submitted to short-(3 days) and long-term (14 days) celecoxib administration, while the respective control groups received equivolumetric saline intraperitoneal injections. The upper left first molars of all rats were moved mesially for 14 days by a fixed orthodontic appliance exerting 50 g force upon insertion. After the experimental period, tooth movement was quantified and tissues around the first molar were processed for tartrateresistant acid phosphatase (TRAP) histochemistry. The amount of tooth movement and the number of TRAP-positive cells on the alveolar bone surface were evaluated. Results: The amount of tooth movement was significantly reduced in rats submitted to short-and long-term celecoxib administration, while the number of osteoclasts on the alveolar bone did not differ between the four groups studied. Conclusions: The hypothesis is rejected. Although celecoxib administration did not affect the number of osteoclasts, the osteoclast activity might be reduced, which could explain the inhibition of tooth movement observed in the celecoxib-treated animals. These results indicate that orthodontists should be aware of patients under short-and long-term therapy with celecoxib.

Morphological changes in the topography of dental surfaces, especially if related to enamel loss and roughness, are of considerable clinical importance. The quantitative evaluation method used herein enables a more comprehensive understanding of the effects of orthodontic bonding on teeth.

The results were submitted to descriptive analysis (mean and standard deviation), test F and "t" Student test with significance level of 5%. There was no significant difference between the group with nasal breathing and the group with predominantly mouth breathing for any of the studied variables.

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