Treatment results
Overall treatment time was less than 1 year of active treatment. After
10 months of treatment, the treatment objectives had been successfully
fulfilled. The treatment was completed in one phase with no additional
refinement required. Forty-four aligners were used as planned by the
ClinCheck, where 24 aligners were used for upper molars distalization
and the other 20 aligners were used for incisor retraction and
finishing. Post treatment records demonstrate satisfactory final results
with all objectives achieved (Fig. 4) . Extraoral photos show an
enhanced profile and improved lip competency. The smile of the patient
was restored with optimal smile arc and decreased gum show. Intraoral
examination reveals coincident upper and lower dental midlines, class I
canines and molars bilaterally, adequate overjet and overbite and ovoid
well aligned upper and lower arches. Post-treatment panoramic
radiography showed good root parallelism, no signs of crestal bone
height reduction and no evidence of apical root resorption.
Cephalometric and digital model superimpositions highlight the
distalisation of upper molars with no vertical movement and retraction
of upper incisors. There was a mild extrusion of lower molar and
proclination of the lower incisors due to the use of class II elastics
which helped reduce the overjet and attain incised contact(Figs. 5 and 6) . The patient was very satisfied with the
treatment results. For retention, the patient had Vivera removable
retainers and follow up examination after 1 year of retention showed
stable treatment results (Fig. 7) .
DISCUSSION
The aim of the present case report is to explain the management of a
dental class II malocclusion case using CAT, where the patient was not
willing to undergo fixed appliance therapy. CAT with intermaxillary
elastics enabled resolution of the malocclusion within a treatment time
comparable with that required for conventional fixed appliance therapy,
providing the patient with comfortable, practical and an esthetically
pleasing appliance. There were controversies over whether moderate to
difficult malocclusions can be successfully accomplished with
CAT.5,
7
The distalization of maxillary molars is frequently the treatment of
choice required in class II non extraction patients. Distalization
achieved in this case was 2.5mm with no observed vertical movement.
These findings are in accordance with the mean reported distalization
values by Ravera et
al14on 20 non growing
patients (2.52mm) and Simon et
al15 on 30 adult
patients (2.7mm), who reported the highest accuracy for bodily distal
movement of molars of 87%. The authors further emphasized the greater
accuracy when the movement was supported by the presence of attachments.
In the present case, attachments were planned on most teeth to guide
their movement and control their axes, resulting in higher
predictability of movements. Different attachment angulations and
geometries were planned, where vertical attachments were placed on the
premolars and molars to prevent tipping and allow for bodily
distalization. The attachments were located on the mesial side of the
upper molars to prevent any mesial rotation of molars. Additionally,
paired vertical root control attachments on the canines bilaterally were
placed to help achieve bodily movement and control their long axes
during distalization. Horizontal attachments were also planned on upper
incisors for extra retention and firmer grip of the aligner. On the
contrary, Saif et al 3stated that although distalization can be successfully attained in adult
patients with a mean of 2.6mm, significant anchorage loss occurs and the
use of attachments has no enhancement effect on distalization. This was
further elaborated by a systematic review in 2019 concluding that
attachment incorporation is not necessary when molar distalization is
planned.10
Furthermore, Simon et
al15 highlighted the
importance of staging in increasing the predictability of distalization.
This was also observed in our case, where sequential distalization was
planned on 24 stages of aligner treatment, hence achieving the highest
predictability of distalization.
The increased overjet was corrected by a combination of upper molars
distalization, upper incisor teeth retraction and lower incisor
proclination. This was facilitated by the use of class II elastics to
augment the anchorage and aid in class II correction. However, short
class II intermaxillary elastics were placed from upper premolars to
lower molars, unlike the conventional attachment from upper canines to
lower molars. The reason behind that protocol was that in this case, it
is desirable to avoid the vertical reciprocal forces from elastics to
act on the upper anterior teeth, leading to further bite deepening by
the clockwise rotation of the upper anterior teeth. In contrast,
Patterson et al in 2020 observed on a sample of 80 adult patients, that
no significant class II correction or overjet reduction were achieved
with class II elastics for an average of 7 months using ABO model
grading system.16
To quantify the amount of tooth movements in the present case, two
methods of superimpositions were utilized which were the ClinCheck
software superimpositions and the 2D lateral cephalometric
superimpositions.
In the present case report, the aligner change was performed every two
weeks. Recently, Align Technology has indicated that weekly changes of
aligners can be made. A study evaluating the effect of 7 days versus 14
days of aligner wear concluded that the 14 day changes revealed greater
accuracy in posterior
movements.17 Moreover,
the tooth requires a period of adaptation for recovery to aid in
stabilization and increase
retention.18
The whole treatment objectives were accomplished in one phase with no
additional refinements in 10 months. This is considered to be a great
advantage for CAT where it was proved to result in a significantly
shorter treatment duration than with
braces.19 Patterson et
al findings contradict our findings where they stated that additional
refinements were necessary to address problems created during
treatment.16
CONCLUSIONS
Combined use of aligners with appropriate attachment location and
geometry is an efficacious means of resolving more complex orthodontic
issues such as class II malocclusions within a time-frame comparable, if
not less, to conventional fixed orthodontics, but with excellent
esthetics, oral hygiene and quality of life. Proper planning and ideal
case selection are essential for achieving the highest predictability of
movements. Staging is crucial in molar distalization in CAT.
Consent for publication
Written informed consent was signed by the patient for the inclusion of
her images for the purpose of publication.
Availability of supporting data
All data generated or analysed during this study are included in this
article in the form of table and figures.
Competing financial and/or non-financial interests
The authors declare that they have no competing interests or other
interests that might be perceived to influence the results and/or
discussion reported in this paper.
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Table 1: Cephalometric analysis pre and post treatment