Rates of tooth movement and bone remodeling activity : self-ligating versus conventional brackets

Background: Bracket systems have been developed with the purpose of reducing frictional resistance between the archwire and accessories. The aim of this research was to compare rates of tooth movement and regions of cellular bone modeling activity along tooth root surfaces of teeth moved with conventional vs. self-ligating brackets. Material and Methods: The experiments were conducted in 20 male dogs. Bands were cemented in all intermediate incisors, with conventional brackets (Morelli) on the right side and hybrid self-ligating ones (T3-American Ortho-dontics) on the left side. A 0.019? x 0.025? stainless steel wire was inserted passively in the slot of these brackets with chain elastics (250 gf) to perform sliding mechanics. Clinical records of the orthodontic mechanics were made before and after 15 days of the tooth movement. The dental segments of the animals were prepared for light micros-copy. Statistical analysis of variance and the Tukey correction with a P value at 5% were used. Results: There were no significant differences in tooth movement rates between the two types of brackets but di-fferences, in the bone modeling activity, suggested that tooth movement with the self-ligating brackets resulted in more tipping and less translational movement than tooth movement with the conventional brackets. Conclusions: The rates of tooth movement were similar between the two systems. The histological evaluation of cellular bone modeling activity along tooth root surfaces showed more translation movement of teeth with the con-ventional brackets, and more tipping movement of teeth with self-ligating brackets

Estudo comparativo in vitro da resistência ao cisalhamento da colagem e do índice de remanescente adesivo entre os compósitos Concise e Fill Magic A in vitro comparative stuabout shear bond strength and adhesive remnant index of the Concdy ise and Fill Magic composites

OBJETIVO: comparar a resistência ao cisalhamento da colagem e o Índice de Remanescente Adesivo (IRA) entre os compósitos Concise e Fill Magic Orthodontic. METODOLOGIA: a amostra consistiu de 24 incisivos inferiores permanentes bovinos divididos em dois grupos. No primeiro grupo foram colados 12 braquetes com o compósito Concise e no segundo grupo 12 com o compósito Fill Magic Orthodontic. Foi feito o ensaio de cisalhamento e a avaliação do IRA de toda a amostra. RESULTADO E CONCLUSÃO: não foram encontradas diferenças estatísticas significantes entre as colagens, nos dois itens avaliados.<br>AIM: to compare the shear bond strength and adhesive remnant index (IRA) between the composites Concise and Fill Magic Orthodontic. METHODS: the sample consisted of 24 cattle permanent low incisors divided in two groups. In the first group 12 brackets were bonded with the Concise composite and in the second group 12 with the Fill Magic Orthodontic composite. The tests of the shear and the evaluation of the ARI were developed with the whole sample. RESULTS AND CONCLUSION: there were not significant statistic differences between the composites in the two evaluated items