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

differences between the groups; the comparisons between Table 2. P-values for group-to-group comparisons
pairs were made using the Mann-Whitney test. The Krus- of shear strength, using the Mann-Whitney test.
kal-Wallis and Mann-Whitney tests were also used to verify the
differences in ARI scores between the groups. The adopted lev- Groups 2 3 4 5 6 7 8
el of significance was 5% (α=0.05). The data were tabulated and 1 <0.001 <0.001* <0.001* 0.003 0.001 <0.001* <0.001*
analyzed in the software program IBM SPSS Statistics for Win-
dows (IBM SPSS. 21.0, 2012, Armonk, NY: IBM Corp.). 2 0.494 0.130 0.141 0.756 0.852 0.002
3 0.178 0.111 0.950 0.443 0.001
Results 4 0.002 0.330 0.044 0.011
5 0.120 0.085 <0.001*
Based on the results, it was demonstrated that the mesh
(Group 8) was the accessory that resulted simultaneously in 6 0.419 0.003
the highest shear strength values and highest ARI scores. (Fig- 7 <0.001*
ure 2). The shear strength of the mesh differed statistically 1 – composite lingual button; 2 – hook for applying traction to impact-
from that of all other materials (Table 2) and its ARI score did ed teeth; 3 – hook with chain; 4 – cleat; 5 – bracket; 6 – convex lingual
not differ only from the hook for applying traction to impact- button; 7 – concave lingual button; 8 – mesh.
ed teeth and the hook with chain (Table 3). The lowest shear
strength was observed with the use of the composite lingual
button (Group 1) (Figure 2A), which differed statistically from Table 3. P-values for group-to-group comparisons of ARI,
all other materials (Table 2). The lowest ARI values were ob- using the Mann-Whitney test.
served with the use of brackets (Figure 2B), which differed sta-
tistically from the hook for applying traction to impacted Groups 2 3 4 5 6 7 8
teeth, the hook with chain and the mesh (Table 3). 1 0.063 0.003 0.521 0.227 0.517 0.825 0.008

2 0.148 0.022 0.003 0.242 0.070 0.061
3 0.001 <0.001* 0.022 0.002 0.181
4 0.587 0.231 0.394 0.004
5 0.071 0.146 0.001
6 0.616 0.017
7 0.005
1 – composite lingual button; 2 – hook for applying traction to impact-
ed teeth; 3 – hook with chain; 4 – cleat; 5 – bracket; 6 – convex lingual
button; 7 – concave lingual button; 8 – mesh.

Discussion

Various devices have been designed for bonding to the
enamel of a tooth to which orthodontic traction will be ap-
plied. 14,17 Choosing a device depends on individual preferences
since there is no scientific proof in the literature, up to the pres-
ent moment, indicating which accessory best adheres to the
tooth surface, in order to avoid debonding during the applica-
tion of traction and the need for a new surgical intervention. 7,8
Based on this premise, the authors’ proposal in the present
study was to evaluate the in vitro shear bond strength and ARI
of different orthodontic accessories used for applying traction to
impacted teeth. It is worth pointing out that, up to now, there are
no studies in the international scientific literature with this pro-
Figure 2. Comparison of shear strength (A) and adhesive posal, and, thus, the results of this research are unprecedented.
remnant index – ARI (B) – between groups. Columns A shear bond strength between 5.8 and 7.8 MPa is neces-
represent means and error bars represent the standard
deviations. *Kruskal-Wallis Test. Comparison of shear sary to achieve satisfactory results with the use of orthodontic
strength (A) and adhesive remnant index – ARI (B) – accessories since it allows to bear the interactions between the
between groups. Columns represent means and error bars masticatory forces and those derived from orthodontic me-
represent the standard deviations. *Kruskal-Wallis Test. 18,19
chanics. Nevertheless, as the impacted teeth are not in