Objective: To evaluate the influence of enamel etching on tensile bond strength of orthodontic brackets bonded with resin-reinforced glass ionomer cement.
Materials and Methods:The sample group consisted of 15 patients who had indications for extraction of four premolars for orthodontic reasons, equally divided into two different groups according to bracket and enamel preparation. Brackets were bonded in vivo, by the same operator, using a split mouth random technique: Group 1 (control), phosphoric acid ϩ Fuji Ortho LC; Group 2, Fuji Ortho LC without acid conditioning. The teeth were extracted after 4 weeks using elevators. An Instron Universal Testing Machine was used to apply a tensile force directly to the enamel-bracket interface at a speed of 0.5 mm/min. The groups were compared using a MannWhitney U-test and Weibull analysis. Results: Mean results and standard deviations (in MPa) for the groups were: Group 1, 6.26 (3.21), Group 2, 6.52 (2.73). No significant difference was observed in the bond strengths of the two groups evaluated (P ϭ .599). Conclusions: Fuji Ortho LC showed adequate shear bond strength and may be suitable for clinical use.
The purpose of this article is to present an alternative approach to the orthodontic treatment of Angle Class II malocclusion. According to a literature review it was observed that the extraction of upper second molars has proven to be a viable alternative for the treatment of this type of malocclusion. This therapeutic option enables faster first molar retraction and requires less patient compliance. However, the level of development, intraosseous position and morphology of the third molar should be carefully evaluated to ensure its correct positioning in place of the extracted second molar. Two clinical case reports will demonstrate that the sequence of diagnosis and treatment used with this mechanics yields satisfactory functional and aesthetic results.
Abstract
The aim of this investigation was to compare the clinical performance of a glass ionomer cement (GIC) with a composite resin when used for direct bonding of standard edgewise orthodontic brackets. Fourteen patients (10 females, four males), in whom 242 teeth were bonded with brackets, were divided into two groups: GIC (121 teeth) and composite (121 teeth). The brackets were allocated to alternate quadrants and first-time failures were recorded over a period of 24 months. Data were analysed statistically (non-parametric chi-squared test). The results demonstrated a significantly lower unpreviewed debonding index (UDI) (15.7 per cent) for the composite than for the GIC (28.1 per cent) (P = 0.042). The use of heavy archwires was largely responsible for this difference. No difference was observed when light and medium archwires were used. GIC may be a viable alternative to composite for use with light archwires and with limited treatment objectives.
INTRODUÇÃO: as assimetrias faciais representam um desequilíbrio entre as estruturas esqueléticas homólogas da face. A maioria das pessoas apresenta algum grau de assimetria facial, pois é rara a condição de perfeita simetria. Todavia, somente quando é perceptível aos olhos do paciente, essa assimetria passa a ser relevante. Em tal condição, a correção ortocirúrgica ou o tratamento ortodôntico são possibilidades normalmente adotadas. OBJETIVO: o presente trabalho, baseado em uma revisão de literatura, é ilustrado por um caso clínico cujo tratamento consistiu em cirurgia ortognática Le Fort I para avanço e rotação da maxila e, na mandíbula, o tratamento foi conservador. CONCLUSÃO: o conhecimento da queixa principal e da expectativa do paciente e exames de diagnóstico bem realizados são itens importantes na decisão do plano de tratamento e no sucesso do resultado final.
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