IJO VOL. 24 NO. 3 FALL 2013
Table I: Sample characteristics.
Type of anchorage Patients Miniscrews % (miniscrews)
Direct 31 65 35.91
Indirect 71 116 64.08
Total 102 181 100
Table II: Indirect anchorage data.
Indirect anchorage Patients Miniscrews % (miniscrews)
Single Cantilever 23 27 23.27
Two-cantilever 48 89 76.72
Total 71 116 100
Table III: Direct anchorage data.
Direct anchorage Patients Miniscrews % (miniscrews)
Single Cantilever 10 21 32.30
Spring 21 44 67.69
Total 31 65 100
Table IV: Success rates of the installed miniscrews.
Direct Anchorage Indirect Anchorage
Sex Male 20/21 95.23 34/39 87.17
Female 42/44 95.45 67/77 87.01
Area Buccal 19/21 90.47 101/116 87.06
ridge 43/44 97.72 ---------- ----------
and difﬁculties with respect to patient hygiene,
alternative sites should be considered. The aim
of the present study was to determine the success
rate of miniscrews used speciﬁcally for lower
molar uprighting using alternative mechanics
to avoid the positioning of miniscrews in areas
considered more prone to failure.
Our results showed that, the use of direct
anchorage produced excellent results, both
when the miniscrews were placed perpendicular
to the buccal face of the alveolar bone (90.47%
success) and when they were vertically positioned
on the alveolar crest (97.72% success). Only one
miniscrew failed when used on the alveolar crest,
in that instance, because it was fractured during
insertion. The reason for the maintenance of
stability of the vertically inserted miniscrews
is probably related to the fact of that the
two implants were united, so there were no
micromovements that would interfere with the
stability of the ﬁxations.
We also tested the use of cantilevers as direct
anchorage, with 90.47% success, and as indirect
anchorage, with 87.06% success. Cantilevers
are excellent devices for molar uprighting
because they are statically determinate systems,
meaning that the force system they produce
presents a high degree of constancy during
According to Romeo and Burstone 3
(1977), the magnitude of the moment required
to upright a molar has been suggested to be
800g.mm, while the adequate extrusion force
generated at the system should not be over
than 30 gf, to maintain a constant relationship
between the alveolar bone crest and the
enamel-cement junction.4 In cases in which the
extrusion of the molar was counter-indicated,
we decided on the use of a two-cantilever
system that can only be achieved with indirect
The choice of mechanics to be used in molar
uprighting depends on many parameters,
including the anatomical characteristics of the
area and the facial pattern of the patient. In cases
in which there is sufﬁcient bone availability, the
use of two united miniscrews is a very stable
option. However, it should be observed that in
such cases, the miniscrews should be positioned
with the aid of a surgical counter, and the heads
of the miniscrews must be close to one another.
Cantilevers also proved to be adequate options,
and can be used as direct or indirect anchorage,
depending on the need for molar intrusion.
Considering the results of this study, it
can be concluded that both direct and indirect
anchorage can be successfully used for molar uprighting. However, a study with a
greater sample size is indicated.
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