Shear Bond Strength and Adhesive Remnant of Three Protocols used for Bonding Orthodontic Brackets

Objective: To test the shear bond strength and the amount of adhesive remnant on the enamel after debonding of a conventional orthodontic composite system, a flowable composite resin, and a self-adhesive resin cement. Material and Methods: Thirty extracted bovine incisors were allocated in three groups, according to the type of adhesive: Group XT (Transbond XT), Group FL (Flow Z350), and Group RX (RelyX U100). All groups had etching with phosphoric acid. Groups XT and FL received primer before adhesive. Stainless steel metal brackets were bonded using the respective adhesive. Teeth were submitted to shear bond strength (SBS) test, followed by measurement of adhesive remnant. Intergroup comparison of SBS values were performed by one-way Anova and Tukey post-hoc test. Kruskal-Wallis test and the Mann-Whitney U-test were used to compare adhesive remnant. Results: Transbond XT presented higher bond strength than RelyX U100 and Flow Z350; all adhesives exhibited bond failure within the adhesive. All groups showed bond failure occurring within the adhesive. Transbond XT and RelyX U100 left significantly more adhesive remnant on the tooth surface than Flow Z350. Conclusion: All three adhesive systems had bond strength above the minimum for clinical routine use. As regards to bond strength, Transbond XT performed better than the resin cement and the flowable resin. Bond failure occurred within the adhesive in all groups.

A proporção áurea como complemento na determinação da dimensão vertical / The golden proportion as a method for the determination of complementary vertical dimension

O objetivo deste estudo foi avaliar se as medidas faciais utilizadas em métodos tradicionais para determinação da Dimensão Vertical de Oclusão estão em Proporção Áurea (1: 1,618) e, por conseguinte, se podem ser utilizadas como método complementar para determinação desta dimensão. Foram selecionados aleatoriamente pacientes entre 20 e 30 anos, da clínica de Odontologia da Universidade Estadual da Paraíba. A amostra foi composta por 30 indivíduos, sendo 15 do gênero masculino e 15 do gênero feminino. Através da análise de fotografias frontais destes indivíduos, e traçados que trespassam pontos cefalométricos, foi possível elucidar novas abordagens nos tratamentos de reabilitação oral. Em relação ao grau da DTM dos pacientes pesquisados, 63,3% (n = 19) apresentavam algum grau de DTM, sendo que 50% (n = 15) apresentavam DTM leve, 10% (n = 3) apresentavam DTM moderada e apenas 3,3% apresentavam DTM severa. O restante, 36,7% (n = 11), não apresentava sinais ou sintomas de disfunções de ATM. Podemos afirmar, através deste estudo, que em pacientes sem DTM tanto os métodos de mensuração facial como os métodos fisiológicos, como o de Litle modificado por Tamaki, são eficientes na determinação da Dimensão Vertical. Porém, em pacientes com disfunções, os métodos se mostraram imprecisos.

The purpose of this study was to evaluate whether the facial measures used in traditional methods of determination of the Occlusion Vertical Dimension are in Divine Proportion (1:1,618) and, subsequently, whether this Proportion can be used as a complementary method for determination of the dimension. For that, 20 to 30 year-old patients were selected at random from Odontology Clinics of the Paraíba State University. The sample was composed by 30 individuals, 15 of male gender and 15 female gender. Through the analysis of frontal photographs of these individuals, and the designs that trespass cephalometric points, it was possível to elucidate new approches on treatements of oral reabilitation. With regard to the degree of the Temple-mandible Disfunction, 63,3% (n=19) of the patients showed some degree of TMD, of whom 50% (n=15) showed mild TMD, 10% (n = 3) showed moderate TMD and only 3.3% showed severe TMD. The rest, 36.7% (n=11), did not show any signs or symptoms of TMA disfunctions. We can state that in patients without TMD, both the methods of facial measures and physiologic methods, such as Litle's Method modified by Tamaki, are efficient in the determination of the Vertical Dimension. However, in patients with TMD the physiologic methods were imprecise.