Mohammadi Amir, Pourkhameneh Sohrab, Sadrhaghighi Amir-Houman
Orthodontist, Associate Professor, Department of Orthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, East Azerbaijan, Iran.
Orthodontist, Private Practice, Ardabil, Iran.
J Clin Exp Dent. 2018 Jun 1;10(6):e548-e554. doi: 10.4317/jced.54733. eCollection 2018 Jun.
Amount of pressure exerting on orthodontic brackets during bonding can create different thickness of adhesive and affect shear bonding strength(SBS) in different adhesive systems. The purpose of this study was to evaluate the effect of different force magnitudes for placement of brackets on SBS.
In an study, 420 brackets were placed on the bovine teeth, using three types of adhesives, Concise (chemically cured two-paste mix), Unite (chemically cured no mix), and Transbond XT( light cured), with the application of seven force magnitudes of 50, 100, 200, 300, 400, 600 and 1000 grams in twenty-one groups of twenty samples each. SBS means (using two-way ANOVA with Tukey's post-hoc test) and adhesive remnant index were compared between these twenty-one groups.
SBS increased with an increase in force. No increase in Transbond XT SBS happened after 400 grams. In addition, Transbond XT had the lowest bond strength among three adhesives (<0.001). Adhesive remnant index (ARI) results also indicated a shift in the failure mode from bracket-adhesive interface to adhesive-enamel interface, as the bonding force got heavier (<0.05).
The force applied on bracket during bonding influences the SBS. In order to have higher bond strength, application of heavy force would be advisable. It is also recommended that constant forces be applied for bracket bonding in future studies. Adhesive, ARI, Bonding procedures, SBS, shear bond strength.
正畸托槽粘结过程中施加的压力大小会导致粘结剂厚度不同，并影响不同粘结系统中的剪切粘结强度（SBS）。本研究的目的是评估托槽放置时不同力大小对SBS的影响。
在一项研究中，使用三种类型的粘结剂，即Concise（化学固化双糊剂混合）、Unite（化学固化非混合）和Transbond XT（光固化），在牛牙上放置420个托槽，分为21组，每组20个样本，分别施加50、100、200、300、400、600和1000克七种力大小。比较这21组之间的SBS均值（使用双向方差分析和Tukey事后检验）和粘结剂残留指数。
SBS随力的增加而增加。400克后Transbond XT的SBS没有增加。此外，Transbond XT在三种粘结剂中粘结强度最低（<0.001）。粘结剂残留指数（ARI）结果还表明，随着粘结力增大，失效模式从托槽-粘结剂界面转移到粘结剂-牙釉质界面（<0.05）。
粘结过程中施加在托槽上的力会影响SBS。为了获得更高的粘结强度，建议施加较大的力。还建议在未来的研究中对托槽粘结施加恒定的力。粘结剂、ARI、粘结程序、SBS、剪切粘结强度。
