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rev port estomatol med dent cir maxilofac . 2017;58(4):219-224 223

occlusion, the masticatory forces do not act on the interface – orthodontic mesh presented the best results both in
20
between the tooth enamel and the accessory for traction. shear strength tests and in the adhesive remnant index;
Therefore, the forces used for applying traction to impacted – brackets showed the worst results in the adhesive rem-
teeth range between the values of 20-150 grams-force. 21-23 nant index;
In all the groups tested, this value was achieved when the – the hypothesis was rejected since the accessories pre-
means were evaluated, except in the composite lingual button sented different strengths of resistance.
group (mean = 3.7 MPa). This fact may be explained by the
composition of this accessory, consisting of polycarbonate
with glass fiber. Some studies have analyzed orthodontic ac- Ethical disclosures
cessories constituted by this composite and have proved that,
when compared with other metal orthodontic accessories, Protection of human and animal subjects. The authors
these have a lower bond strength than the metal type. 24-26 Fur- declare that no experiments were performed on humans or
thermore, it is pointed out that this value shows a trend to animals for this study.
decrease in clinical situations since some elements such as
saliva and blood are present, and thus make it difficult to bond Confidentiality of data. The authors declare that no patient
orthodontic accessories to tooth enamel. 27-32 data appear in this article.
It should be emphasized that the only group in which all
specimens showed results above the reference value was the Right to privacy and informed consent. The authors declare
group with the orthodontic mesh, which presented statistical- that no patient data appear in this article.
ly significant differences comparing with all the other groups.
Although a bond strength of over 14 MPa may cause damage
to the tooth surface, this did not occur in any specimen of Conflict of interest
33
the mesh group, as opposed to the group of the hook for ap-
plying traction to impacted teeth (GTDI), in which two speci- The authors have no conflicts of interest to declare.
mens presented enamel fractures. This fact may be explained
by the design of the base of these orthodontic accessories.
Regarding the ARI, the best results were also obtained in Acknowledgments
the orthodontic mesh group (mean = 1.4), thus ratifying that
orthodontic accessory bonding is most effective when a failure The authors thank the help of Diego Adrini Carvalho de Souza
occurs by cohesive rupture of the material; that is, when ad- and Monique Santos Albuquerque during the confection of
34
hesive remnants are found adhered to the tooth. The worst the samples.
results were found in the bracket group (mean = 0.2), and this
group presented statistically significant differences in com-
parison with the hook for applying traction to impacted teeth references
(GTDI), the hook with chain (GC) and the mesh.
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to light the strong correlation between the bond strength at the impact and level of satisfaction with orthodontic treatment.
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adhesive-enamel interface and the ARI. Furthermore, other Rev Port Estomatol Med Dent Cir Maxilofac. 2016;57:247-51.
advantages may be pointed out, such as the possibility of using 2. Kim Y, Hyun HK, Jang KT. The position of maxillary canine
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lingual, mesial or distal) and providing less discomfort. 36 3. Jung YH, Kim JY, Cho BH. The effects of impacted
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The limitation of this study is that it was conducted in Imaging Sci Dent. 2016;46:251-8.
vitro, therefore excluding some important variables arising in 4. Ghaeminia H, Perry J, Nienhuijs ME, et al. Surgical removal
the clinical practice that have a direct influence on the bond versus retention for the management of asymptomatic
of accessories to the surface of a tooth that will be submitted disease-free impacted wisdom teeth. Cochrane Database
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– the polycarbonate and glass fiber button did not show Orthod Dentofacial Orthop. 1992;101:159-71.
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– stainless steel accessories showed good strength and are and ankylosed maxillary canines. Am J Orthod Dentofacial
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