Fábio Lourenço Romano

Shear Bond Strength of Metallic Orthodontic Brackets Bonded to Enamel Prepared with Self-Etching Primer

The aim of this study was to determine the shear bond strength of different composites and to determine the adhesive remnant index (ARI) of metallic brackets bonded to enamel prepared with Transbond Plus Self-Etching Primer (TPSEP). Forty human premolars were divided into four equal groups. In group 1 (control), the Transbond XT was conventionally used. In groups 2-4, the TPSEP was used before bonding with Transbond XT, Z-100, and Concise Orthodontic, respectively. After the bonding, the samples were stored in distilled water at 37 degrees C for 24 hours. The brackets were debonded using a universal testing machine at a crosshead speed of 0.5 mm/ min. The shear bond strength (MPa) for group 1 (control), group 2 (TPSEP + Transbond XT), group 3 (TPSEP + Z-100), and group 4 (TPSEP + Concise Orthodontic) were of 6.43, 4.61, 4.74, and 0.02, respectively. Group 1 was statistically superior to other groups (P < .05), but there was no statistically significant difference between groups 2 and 3 (P > .05), although both were statistically superior to group 4 (P < .05). According to the ARI evaluation, most of the failures involved the bracket/composite interface (groups 1 and 2) as well as the enamel/composite interface (groups 3 and 4). The Transbond XT conventionally bonded showed better adhesion results than Transbond XT, Z-100, and Concise Orthodontic after using Transbond Plus Self-Etching Primer.

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.

Analysis of the coefficient of variation in shear and tensile bond strength tests

The coefficient of variation is a dispersion measurement that does not depend on the unit scales, thus allowing the comparison of experimental results involving different variables. Its calculation is crucial for the adhesive experiments performed in laboratories because both precision and reliability can be verified. The aim of this study was to evaluate and to suggest a classification of the coefficient variation (CV) for in vitro experiments on shear and tensile strengths. The experiments were performed in laboratory by fifty international and national studies on adhesion materials. Statistical data allowing the estimation of the coefficient of variation was gathered from each scientific article since none of them had such a measurement previously calculated. Excel worksheet was used for organizing the data while the sample normality was tested by using Shapiro Wilk tests (alpha = 0.05) and the Statistical Analysis System software (SAS). A mean value of 6.11 (SD = 1.83) for the coefficient of variation was found by the data analysis and the data had a normal distribution (p>0.05). A range classification was proposed for the coefficient of variation from such data, that is, it should be considered low for a value lesser than 2.44; intermediate for a value between 2.44 and 7.94, high for a value between 7.94 and 9.78, and finally, very high for a value greater than 9.78. Such classification can be used as a guide for experiments on adhesion materials, thus making the planning easier as well as revealing precision and validity concerning the data.

Análise in vitro da resistência ao cisalhamento de braquetes metálicos colados em incisivos bovinos e humanos

The purpose of this study was to compare shear bond strength of steel brackets in bovine and human teeth and observe adhesive remnant index (ARI). The sample consisted of thirty teeth, divided into three groups: human permanent lower incisors, bovine permanent lower incisors and bovine deciduous lower incisors. Prophylaxis has been made with pumice and water, followed by enamel acid etching with phosphoric acid at 37% on the surface of the teeth. Steel brackets were bonded with Concise composite according to the manufacturer instructions, and they were submitted to a shear bond strength test for a 0,5 mm / minute speed. The medium values of bond strength in human permanent lower incisors was of x= 12,96 MPa, in bovine permanent lower incisors of x= 15,05 MPa, and bovine deciduous lower incisors of x= 17,03 MPa. There were not significant estatistic differences among the groups, not for strength shear values nor for the evaluation of the ARI.

Shear bond strength of metallic brackets photo-activated with light-emitting diode (LED) at different exposure times

The purpose of this study was to compare the shear bond strength of orthodontic metallic brackets photo-activated with two different light-curing sources at different exposure times: halogen light (XL 1500, 3M ESPE) and LED light (Ortholux, 3M Unitek). Sixty bovine permanent lower incisors were inserted into PVC tubes containing plaster. The buccal surfaces were cleaned with pumice and water, and then etched with 37% phosphoric acid gel. The XT Primer bonding agent (3M Unitek) was applied to the enamel surfaces and the metallic pre-coated brackets (Transbond APC II system, 3M Unitek) were attached to upper central incisors. The teeth were randomly divided into four groups (n=15). In Group I (Control), halogen light was used for 40 seconds, while in Groups II, III, and IV were light-cured with LED light unit for 40, 10, and 5 seconds, respectively. The teeth were stored in distilled water at 37°C for 24 hours. The brackets were submitted to shear bond strength test in universal testing machine (Instron) at a crosshead speed of 0.5 mm/minute. Shear bond strength means (MPa) were 4.87 for Group I; 5.89 for Group II; 4.83 for Group III, and 4.39 for Group IV. Tukeys test detected no statistically significant differences among the groups regarding the shear bond strength (p>0.05). Neither of the types of light-curing sources or exposure times influenced the shear bond strength of metallic brackets.

Avaliação da resistência ao cisalhamento do compósito Right-On em diferentes condições de esmalte

OBJECTIVE: To evaluate the shear bond strength of metallic brackets bonded with Right-On composite under different enamel conditions. MATERIALS AND METHODS: Forty-five bovine permanent lower incisors were used, and were divided into three groups (n = 15). For group 1 (control), the bonding procedures were performed by using Transbond XT according to the manufacturerx92s recommendations, that is 37% phosphoric acid etching, washing, drying, application of primer XT and, finally, the bonding procedure itself. For the other two groups, the brackets were bonded by using the Right-On composite. The bonding procedures for group 2 were performed according to the manufacturerx92s recommendations, that is 37% phosphoric acid etching, application of the composite activation liquid, both on the etched surface and the bracketx92s base, and insertion of the composite on the bracketx92s base and bracket positioning. In group 3, the dental surface was etched by using Transbond Plus Self-Etching Primer, and the composite activator liquid was applied on the bracketx92s base only. Following the bonding procedures, the shear bond strength test was performed by using an Instron machine at the speed of 0.5mm/min. for mechanical tests. RESULTS AND CONCLUSION: Results showed no statistical differences between groups 1 and 2 (p > 0.05). However, both groups were statistically superior to group 3 (p < 0.05). A greater number of fractures on the bracket/composite interface was evidenced by the ARI results.

Análise da qualidade de adesão de diferentes bases de braquetes metálicos

Considering the differences in the bracket bases currently used, it was performed a study with the purpose of comparing three different metallic bracket bases commercially available. It was used 36 human bicuspids divided into 3 groups of 12 teeth. These teeth were immersed in a troquel with gypsy stone type IV and positioned with their buccal face perpendicular to the troquel base. For each group of teeth it was bonded one of the three brackets using Concise Orthodontic composite. Afterwards they were submitted to a shear bound strength test in a universal machine calibrated for a 0,5mm/minute speed. Monobloc bracket base showed the greater mean value of adhesive resistance (x = 28,19 Kgf/cm2), result statistically superior to that shown by Equilibrium (x = 18,07 Kgf/cm2) and Dynalock (x = 18,24 Kgf/cm2) ones. The ARI (Adhesive reminiscent index) showed no statistically difference among the bracket bases studied.

Oxidação de braquetes metálicos

* Mestre em Ortodontia pela Faculdade de Odontologia de Piracicaba / UNICAMP. Professor do Curso de Especialização em Ortodontia – Efoa / Ceufe. ** Professor Titular da área de Materiais Dentários – Departamento de Odontologia Restauradora da Faculdade de Odontologia de Piracicaba – UNICAMP. *** Professor Titular da área de Materiais Dentários – Departamento de Odontologia Restauradora da Faculdade de Odontologia de Piracicaba – UNICAMP. **** Professora-Doutora da área de Ortodontia – Departamento de Odontologia Infantil da Faculdade de Odontologia de Piracicaba – UNICAMP. ***** Professor Titular da área de Ortodontia – Departamento de Odontologia Infantil da Faculdade de Odontologia de Piracicaba – UNICAMP. que defeitos na estrutura dos mesmos causem danos ao esmalte do paciente. Não é raro observarmos algumas alterações como fraturas, aletas amassadas, separação da malha do restante do braquete, entre outros problemas, porém, cita-se em especial a oxidação da base do braquete (Fig. 1A, B). Quando na cavidade bucal o acessório não é capaz de resistir aos fluidos bucais, liberando substância de cor negra na superfície do esmalte. Diante desta situação, o ortodontista deve A colagem de braquetes diretamente ao esmalte dentário é um procedimento simples, que traz grandes vantagens estéticas ao paciente e benefícios ao profissional. Porém, deve-se usar técnica adequada e criteriosa, respeitando os passos indicados pelos fabricantes. Além disto, deve-se utilizar materiais de qualidade comprovada por pesquisas clínicas e laboratoriais. Na grande maioria das vezes a colagem do braquete é realizada com sucesso, entretanto, esta deve ser verificada durante todo o tratamento com a finalidade de evitar

Association between Tooth Agenesis and Skeletal Malocclusions

ABSTRACT Objectives The aim of this study was to evaluate the association between tooth agenesis and skeletal malocclusions in Brazilian non-syndromic orthodontic patients. Material and Methods Pretreatment orthodontic records of 348 patients of both genders and with various skeletal malocclusions were examined. Tooth agenesis was evaluated in panoramic radiographs. Angular measurements were taken from lateral cephalometric radiographs to classify the patient’s malocclusion as skeletal Class I, Class II and Class III. Subjects were divided into 2 groups, “with tooth agenesis” and “without tooth agenesis”. Chi-square or Fisher exact test was used to compare categorical data. ANOVA with Tukey’s post-test was used for means comparisons. An alpha of 5% was established. Results From 348 analysed patients, 28 presented tooth agenesis. There was no difference between genders (P = 0.27) nor mean age (P = 0.16). The most prevalent skeletal malocclusion was Class I (63.11%), followed by Class II (25.94%), and Class III (10.95%). The mean of congenitally missing teeth was 1.3 (SD 0.13). Thirteen subjects had premolar agenesis, 13 upper lateral incisor agenesis, 4 lower incisor agenesis and 2 molars agenesis. The group with tooth agenesis presented A point-nasion-B point (ANB) angle smaller (1.66 [SD 2.52]) than the group without tooth agenesis (2.86 [SD 2.49]) (P = 0.01). ANB angle had a negative correlation with the number of congenitally missing teeth (P = 0.039; r = -0.39). Conclusions Tooth agenesis is associated with a smaller A point-nasion-B point angle and is negatively correlated with the number of congenitally missing teeth.

Cimentação de banda ortodôntica com novo cimento de ionômero de vidro modificado por resina

The aim of this study is to show the orthodontic application of the resin-modified glass ionomer cement Fuji Ortho Band. The clinical sequence of band cementation with this material was explained, being with each step of procedure illustrated, as: band selection and adaptation, prophylaxis and Fuji Ortho Band cement manipulation according to the manufacturers ́ instructions and properly cementation. DescRiptoRs: Glass ionomer cements – Orthodontics. ****** Doutorando em Ortodontia Faculdade de Odontologia de Piracicaba FOP – Universidade Estadual de Campinas UNICAMP; Professor de Ortodontia da Universidade Federal de Alfenas – UNIFAL ****** Professor Titular da área de Materiais Dentários – Faculdade de Odontologia de Piracicaba FOP – Universidade Estadual de Campinas UNICAMP ****** Doutorando em Ortodontia – Faculdade de Odontologia de Piracicaba FOP – Universidade Estadual de Campinas UNICAMP ****** Doutor em Ortodontia – Faculdade de Odontologia de Piracicaba FOP – Universidade Estadual de Campinas UNICAMP; Professor de Ortodontia da Universidade de Ribeirão Preto – UNAERP ****** Professora Doutora da área de Ortodontia – Faculdade de Odontologia de Piracicaba FOP – Universidade Estadual de Campinas UNICAMP ****** Professor Titular de Ortodontia da Faculdade de Odontologia de Piracicaba FOP – Universidade Estadual de Campinas UNICAMP cimentAção De bAnDA oRtoDônticA com novo cimento De ionômeRo De viDRo moDificADo poR ResinA ORthOdOntiC band CimentatiOn with new ReSin-mOdified glaSS iOnOmeR Cement