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Força de adesão de brackets ortodônticos recolados : comparação de diferentes métodos de preparação da base do bracket
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Abstract(s)
Objetivo: Comparar três métodos de preparação da base de brackets para posterior recolagem e avaliação da sua aplicabilidade clínica
Materiais e métodos: Foram utilizados 45 dentes pré-molares humanos em estado hígido, aos quais foram colados brackets ortodônticos pré-molares Victory SeriesTM (3M Unitek), utilizando o sistema adesivo TransbondTMXT (3M, Unitek). Após uma colagem e descolagem iniciais, os dentes foram aleatoriamente subdivididos em 3 grupos de 15 dentes e foram submetidos a 3 tipos de técnica de reciclagem: no Grupo A os brackets foram limpos com jato de óxido de alumínio; no Grupo B1 os brackets foram limpos superficialmente com pedra verde; no Grupo B2 os brackets foram limpos totalmente, até ser visível a malha com pedra verde. Os brackets foram recolados e submetidos a testes de força de adesão por cisalhamento, à velocidade de 1mm/min. O local da falha de adesão foi caracterizado através do Índice de Remanescente Adesivo (IRA). Na análise estatística foram utilizados os testes ANOVA One-way e Kruskal-Wallis (p ≤ 0,05).
Resultados: As forças médias de adesão obtidas foram de 11,75 ± 4,83 Mpa, 8,22
± 4,01 Mpa e 7,54 ± 2,85 Mpa, respetivamente para o Grupo A, B1 e B2,. Não foram
registadas diferenças estatisticamente significativas entre os Grupos A - B1 (p=0,051) e
entre os Grupos B1 - B2 (p=0,885). Contudo, foram identificadas diferenças
estatisticamente significativas quando comparados o Grupo A com o B2 (p= 0,016).
Quanto ao IRA, foram registadas diferenças estatisticamente significativas entre os
Grupos A - B2 e B1 - B2 (p<0,001), não se identificando diferenças estatisticamente
significativas entre os Grupos A- B1 (p=0,068). Os Grupos A e B1 obtiveram
predominantemente pontuações de 2 e 1 (99% e 86,7%, respetivamente). No Grupo B2,
foi atribuída com maior prevalência a pontuação de 3 (73,3%).
Conclusão: A reciclagem com jato de óxido de alumínio demonstrou ser a técnica
capaz de proporcionar maior força de adesão, seguida pela abrasão superficial com pedra verde. A abrasão total com pedra verde foi a técnica que levou a forças de adesão mais baixas. Quanto ao IRA, nos Grupos A e B1, as falhas foram predominantemente do tipo misto. No Grupo B2, o tipo de falha mais prevalente foi na interface adesivo-bracket.
Aim: To compare three bracket base conditioning methods for posterior rebonding and evaluate their clinical applicability. Materials and Methods: 45 healthy human bicuspids were used, to which were bonded the Victory Series (3M Unitek) orthodontic bicuspid brackets with TransbondTMXT (3M, Unitek). After an initial bonding and debondig, teeth were randomly divided into 3 groups of 15 teeth. Brackets were then subjected to one of 3 recycling techniques: In Group A, brackets were prepared with an aluminum oxide micro blaster; in Group B1, brackets were superficially cleaned using a green stone bur; in Group B2, brackets were fully cleaned, until mesh was visible using a green stone bur. Brackets were rebonded and were then subjected to a shear bond strength test, at a crosshead speed of 1mm/min. The site of bonding failure was characterized using the Adhesive Remnant Index (ARI). One-way ANOVA and Kruskal-Wallis test were applied for the statistical analysis. Results: The average bond strengths registered were 11,75 ± 4,83 Mpa, 8,22 ± 4,01 Mpa and 7,54 ± 2,85 Mpa, respectively for Group A, B1 and B2. No statistically significant differences were reported between Groups A – B1 (p=0,051) and Groups B1 - B2 (p=0,885). However, a statistically significant difference was identified when comparing Groups A and B2 (p= 0,016). As for the ARI, statistically significant differences were reported between Groups A – B2 and B1 – B2 (p<0,001), on the contrary, no statistically significant differences were registered between Groups A- B1 (p=0,068). Groups A and B1 were predominantly scored with 2 and 1 (99% e 86,7%, respectively). In Group B2, the most predominantly score was 3 (73,3%). Conclusion: Recycling with aluminum oxide micro blaster attained the highest bond strength, followed by superficially cleansing with green stone bur. Total cleansing with green stone bur showed the lowest average bond strength. As for ARI, in Groups A and B1 the failures were predominantly of a mixed type. Group B2 showed mostly adhesive-bracket interface type failures.
Aim: To compare three bracket base conditioning methods for posterior rebonding and evaluate their clinical applicability. Materials and Methods: 45 healthy human bicuspids were used, to which were bonded the Victory Series (3M Unitek) orthodontic bicuspid brackets with TransbondTMXT (3M, Unitek). After an initial bonding and debondig, teeth were randomly divided into 3 groups of 15 teeth. Brackets were then subjected to one of 3 recycling techniques: In Group A, brackets were prepared with an aluminum oxide micro blaster; in Group B1, brackets were superficially cleaned using a green stone bur; in Group B2, brackets were fully cleaned, until mesh was visible using a green stone bur. Brackets were rebonded and were then subjected to a shear bond strength test, at a crosshead speed of 1mm/min. The site of bonding failure was characterized using the Adhesive Remnant Index (ARI). One-way ANOVA and Kruskal-Wallis test were applied for the statistical analysis. Results: The average bond strengths registered were 11,75 ± 4,83 Mpa, 8,22 ± 4,01 Mpa and 7,54 ± 2,85 Mpa, respectively for Group A, B1 and B2. No statistically significant differences were reported between Groups A – B1 (p=0,051) and Groups B1 - B2 (p=0,885). However, a statistically significant difference was identified when comparing Groups A and B2 (p= 0,016). As for the ARI, statistically significant differences were reported between Groups A – B2 and B1 – B2 (p<0,001), on the contrary, no statistically significant differences were registered between Groups A- B1 (p=0,068). Groups A and B1 were predominantly scored with 2 and 1 (99% e 86,7%, respectively). In Group B2, the most predominantly score was 3 (73,3%). Conclusion: Recycling with aluminum oxide micro blaster attained the highest bond strength, followed by superficially cleansing with green stone bur. Total cleansing with green stone bur showed the lowest average bond strength. As for ARI, in Groups A and B1 the failures were predominantly of a mixed type. Group B2 showed mostly adhesive-bracket interface type failures.
Description
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Keywords
Reciclagem de brackets Remoção de adesivo remanescente Descolagem ortodôntica Força de resistência ao cisalhamento Força de adesão