Márlio Vinícius de Oliveira

Shear bond strength of orthodontic brackets to enamel under different surface treatment conditions.

The purpose of the present study was to evaluate the shear bond strength to enamel and the adhesive remnant index (ARI) of both metallic and polycarbonate brackets bonded under different conditions. Ninety bovine permanent mandibular incisors were embedded in acrylic resin using PVC rings as molds and assigned to 6 groups (n=15). In Groups 1 (control) and 3, metallic and polycarbonate orthodontic brackets were, respectively, bonded to the enamel surfaces using Transbond XT composite according to the manufacturers recommendations. In Groups 2 and 4, both types of brackets were bonded to enamel with Transbond XT composite, but XT primer was replaced by the OrthoPrimer agent. In Groups 5 and 6, the polycarbonate bracket bases were sandblasted with 50-μm aluminum-oxide particle stream and bonded to the enamel surfaces prepared under the same conditions described in Groups 3 and 4, respectively. After bonding, the specimens were stored in distilled water at 37°C for 24 hours and then submitted to shear bond strength test at a crosshead speed of 0.5 mm/min. The results (MPa) showed no statistically significant difference between Groups 4 and 6 (p>0.05). Likewise, no statistically significant differences (p>0.05) were found among Groups 1, 2, and 5, although their results were significantly lower than those of Groups 4 and 6 (p<0.05). Group 3 had statistically significant lower bond strength than Groups 2, 4, and 6, but no statistically significant differences were found on comparison to Groups 1 and 5. A larger number of fractures at the bracket/composite interface were evidenced by the ARI scores. OrthoPrimer bonding agent yielded higher bond strength in the groups using either conventional or sandblasted polycarbonate brackets, which was not observed in the groups using metallic brackets.

Estudo comparativo in vitro da resistência ao cisalhamento da colagem e do índice de remanescente adesivo entre os compósitos Concise e Fill Magic

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.

Shear bond strength of brackets bonded to enamel with a self-etching primer. Effects of increasing storage time after activation.

OBJECTIVE To evaluate bonding efficacy of activated Transbond Plus Self-Etching Primer (TPSEP) used at different time points with Transbond XT to bond metallic orthodontic brackets to bovine incisors. MATERIALS AND METHODS The inferior incisors of 210 bovines were randomly divided into seven groups (n = 30). TPSEPs were mixed, activated, and kept activated for 30 (group 30), 21 (group 21), 15 (group 15), 7 (group 7), 3 (group 3), or 1 (group 1) days before bonding, and in one group (group 0) TPSEP was used immediately after mixed. At day zero, incisors in each group were bonded in exactly the same way. After applying TPSEP, brackets were bonded with Transbond XT, according to the manufacturers instructions. After 24 hours, shear bond strength (SBS) tests were performed for all samples at a crosshead speed of 0.5 mm/min, and the Adhesive Remnant Index was scored. RESULTS There were no significant differences between the SBS of groups 0, 1, 3, 7, and 15 (P > .05) However, those groups had higher SBS (P < .05) compared with groups 21 and 30. No significant difference (P > .05) was observed between groups 21 and 30. Despite the decrease in SBS for groups 21 and 30, bond strength values were still satisfactory. CONCLUSION After activation, the TPSEP mix can be stored for a period of 15 days without losing its adhesive properties.

Attempted traction of impacted and ankylosed maxillary canines

The aim of this article is to report the clinical orthodontic treatment of an adult patient with 2 impacted maxillary canines. Traction was applied to the impacted teeth; however, after 7 months, the teeth were found to be ankylosed and were extracted. The extraction spaces were closed by moving the posterior teeth mesially with mini-implant anchorage. The results were satisfactory, with the premolars in the functional position of the canines.

Avaliação cefalométrica das alterações verticais e ântero-posteriores em pacientes Classe II esquelética, tratados com aparelho extrabucal de tração cervical ou combinada

AIM: To evaluate the antero-posterior and vertical changes in patients with skeletal Class II malocclusions (ANB > 5o) by means of the cephalometry. The patients had been treated with either cervical traction device (Group 1) or combined traction device (Group 2) both in association with a Edgewise-type device. METHODS: The sample consisted of 60 lateral cephalometric radiographs of 30 Caucasian individuals, 13 males and 17 females, obtained during both pre-treatment and post-treatment phases. The 15 patients of Group 1 had mean ages of 10 years and 7 months in the pre-treatment and 13 years and 9 months in the post-treatment. The other 15 patients of Group 2 had mean ages of 11 years and 5 months in the pre-treatment and 14 years and 9 months in the post-treatment. The cephalometric measures obtained in the beginning as well as in the end of the treatment were analysed and compared by using the Students t test. RESULTS AND CONCLUSIONS: No significant changes regarding the facial growth pattern during the treatment in both groups. In Group 2, whose patients had a tendency of vertical growth (GoGn-SN> 36°), the extraoral combined traction device was not capable of reducing the mandibular plane angle despite of causing no extrusive effect on the upper molars. The anterior movement of the maxilla was restricted, whereas the vertical movement was stable in both groups studied. Although growth and anterior movement of the mandible were observed, the mandibular inclination was unchanged. The maxillary-mandibular relationship was shown to be significantly improved in both groups, with a perceptible reduction of the ANB measure.

Avaliação da citotoxicidade de elásticos ortodônticos intermaxilares

O objetivo do presente trabalho e avaliar a citotoxicidade de quatro diferentes marcas comerciais de elasticos inter-maxilares intra-orais. Foram avaliados elasticos da American Orthodontics (Grupo 1), 3M Unitek (Grupo 2), Morelli (Grupo3) e Uniden (Grupo 4). Os elasticos foram previamente esterilizados em luz ultravioleta e colocados em placas de Petri, as quais continham cultura de celulas HEp-2., Apos 24 h, as monocamadas de celulas foram coradas e, em seguida, realizada uma avaliacao dos halos de difusao e de lise celular. Os resultados demonstraram a ausencia de citotoxicidade nos elasticos da marca American Orthodontic e 3M Unitek e alta citotoxicidade nos elasticos das marcas Morelli e Uniden. Com base nos resultados encontrados, atraves da metodologia utilizada, conclui-se que os elasticos da marca Morelli e Uniden sao citotoxicos.

Skeletal and dental Class II malocclusion, with anterior open bite and accentuated overjet

Open bite is defined as a deficiency in normal vertical contact between antagonist teeth and may manifest in a limited region, or more rarely throughout the entire dental arch. If the lack of contact between teeth is located in the incisor and/or canine region when occlusion is in centric relation, it is called anterior open bite (AOB). Some studies have demonstrated that AOB is strongly associated with non-nutritional sucking habit. This article relates the treatment of a female African-Brazilian patient, with 20 years and 7 months of age, who presented Angles Class II, division 1 malocclusion, AOB, accentuated overjet, lingual interposition during swallowing and difficulty with pronouncing some phonemes. Orthodontic treatment began by mounting an Edgewise Standard fixed appliance system, with a fixed palatal crib appliance and extraction of maxillary first premolars. This case was presented to the Brazilian Board of Orthodontics and Facial Orthopedics (BBO), as part of the requisites to become a BBO Diplomate.