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Objective: To evaluate the effect of two different prophylaxis protocols on the friction force in sliding mechanics during in vivo leveling and alignment., Materials and Methods: The sample comprised 48 hemi-arches divided into three groups according to the prophylactic protocol adopted. Group 1 consisted of patients undergoing prophylaxis with sodium bicarbonate, group 2 consisted of patients submitted to prophylaxis with glycine, and group 3 consisted of patients without prophylaxis, as a control. All patients received hygiene instructions and, with the exception of group 3, prophylaxis was performed monthly. After 10 months, the brackets were removed from the oral cavity and submitted to friction force tests and qualitative analysis by scanning electron microscopy. Analysis of variance followed by Tukey tests was performed for intergroup comparison regarding the friction force., Results: The experimental groups presented significantly smaller friction forces than the group without prophylaxis. Accordingly, qualitative analysis showed greater debris accumulation in the group without the prophylactic procedures., Conclusions: Prophylactic blasting with sodium bicarbonate or glycine can significantly prevent an increase of the friction force during sliding mechanics.

Background: To evaluate the bracket-wire friction force after clinical use., Material and Methods: A systematic search of several electronic databases (PubMed, Embase, Web of Science, Scopus, The Cochrane Library, Lilacs and Google Scholar) without limitations regarding publication year or language, was performed. In-vitro studies analyzing the changes in friction force of orthodontic brackets before/after their clinical use were considered. Risk of Bias was assessed with Downs and Black checklist. All methodological features that could interfere in the results were specifically described., Results: Seven studies satisfied the inclusion criteria and were included in the review. All 7 studies reported at least two groups (before and after clinical use). Friction force increased after intraoral aging in most of the studies. However, there is lack of good quality evidence in this research area., Conclusions: Brackets present increased surface roughness after clinical use, and consequently increased coefficient of friction (COF) and Friction Force. Further studies are necessary to obtain more reliable results. Key words: Friction, orthodontic brackets, systematic review., Competing Interests: Conflict of interest statement:The authors have declared that no conflict of interest exist.

Dentigerous cysts are the most common developmental cysts of the jaws and are associated with impacted teeth. Bilateral dentigerous cysts are rare and typically occur in association with a developmental syndrome. The occurrence of bilateral dentigerous cysts in the absence of a developmental syndrome is very rare. The purpose of this paper was to report on a nonsyndromic, 5-year-old boy who presented mandibular bilateral dentigerous cysts.