2 research outputs found
Avaliação da resistência ao cisalhamento de braquetes colados com resinas ortodônticas fluoretadas
O objetivo deste estudo foi avaliar a resistência ao cisalhamento de braquetes
colados com resinas que contém flúor, e compará-las a uma resina convencional. Para este
estudo, foram utilizados 60 pré-molares extraÃdos por motivo ortodôntico, os quais foram
divididos em 3 grupos, sendo 20 corpos-de-prova para cada um: Grupo I - Concise (3M),
Grupo II Ultrabond (Aditek do Brasil) e Grupo III - Rely-a-Bond (Reliance). Todos os
corpos-de-prova foram armazenados em água destilada a 37C, por 24 horas e termociclados
com 500 ciclos, nas temperaturas de 5C e 55C. Após 48 horas, os corpos-de-prova foram
submetidos aos ensaios mecânicos de cisalhamento na direção ocluso-cervical, na máquina
Material Test System MTS 810, com velocidade de carga de 0,5 mm/min. Para a análise dos
dados, utilizou-se a Análise de Variância, Teste de Levene, Teste de Shapiro-Wilk e o Teste
de Tukey. Os resultados demonstraram uma resistência média ao cisalhamento de 24,54
6,98 MPa para o Grupo I (Concise), de 11,53 6,20 MPa para o Grupo II (Ultrabond) e de
16,46 5,72 MPa para o Grupo III (Rely-a-Bond). A Análise de Variância determinou
diferença estatÃstica entre as médias de resistência ao cisalhamento entre os grupos (p<0,001).
O teste de Tukey evidenciou que as médias dos três grupos foram significativamente
diferentes entre si (p<0,05), com a maior resistência para o Grupo I (Concise) e a menor para
o Grupo II (Ultrabond). Entretanto, todos os materiais apresentaram resistência adesiva
adequada para uso clÃnico.The aim of this study was to evaluate the shear bond strength of brackets
bonded with fluoride-releasing composite resins, and to compare them to a conventional resin.
For this study, sixty premolars extracted due to orthodontic reasons were used, which were
divided into three groups: Group 1- Concise (3M), Group 2- Ultrabond (Aditek do Brasil) and
Group 3- Rely-a-bond (Reliance). All bonded specimens were stored in distilled water at
37C for 24 hours and termocycled between 5C and 55C for 500 cycles. After 48 hours, the
specimens were submitted to the shear bond strength test, in occluso-gingival direction, in
Material Test System MTS 810 machine, with load speed of 0.5 mm/min. Variance Analysis,
Levene Test, Shapiro-Wilk Test and Tukey Test were used for data analysis. The results
demonstrated a mean shear bond strength of 24.54 6.98 MPa for the Concise; 11.53 6.20
MPa for the Ultrabond; and of 16.46 5.72 MPa for the Rely-a-Bond. Variance Analysis
determined a statistical difference amongst groups (p<0.001). Tukey Test evidenced that the
averages of the three groups were significantly different among themselves (p<0.05), with the
highest resistance for the Concise Group and the lowest for the Ultrabond Group. However,
all the materials presented bond strengths, which were suitable for clinical use
Rebonding of unused brackets with different orthodontic adhesives
OBJECTIVE: To compare in vitro shear bond strength (SBS) of different orthodontic adhesives in bonding and repeatedly rebonding metal brackets, and to evaluate the bond failure site with the adhesive remnant index (ARI). METHODS: Specimens consisted of 90 extracted human first premolars, randomly divided into three groups (n=30). The adhesives Alpha Plast (AP), ConciseTM (CO) and TransbondTM XT (TB) were used in each group. Three SBS tests were performed, i.e., one at T0 (initial) and the other two at T1 and T2 (first and second rebondings, respectively), observing a 24-hour interval. The tests were performed in a Shimadzu AG-I (10kN) SBS testing machine, at a speed of 0.5 mm/min. RESULTS: SBS data were subjected to ANOVA, Tukey's test and Bonferroni test (p<0.05). For the ARI, the Kruskal Wallis test was performed, followed by the Dunn test. The results revealed that at T0 groups AP and CO showed SBS values that were near, but above TB values; and at T1 and T2, the highest SBS values were observed for the AP group, followed by the CO and TB groups. CONCLUSION: Statistically significant differences were found in SBS between groups AP, CO and TB during bonding and repeated rebondings of unused metal brackets, with group AP achieving the highest SBS value. Regarding ARI, adhesive AP exhibited bond failure at the enamel-adhesive interface, with a higher enamel fracture frequency