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Limitations and Expectations of Clear Aligner Systems

Doug Willison, Great Lakes OrthoBy Doug Willison, Senior Outside Sales Representative, Great Lakes Orthodontics, Ltd.

Low cost clear aligner systems have been successful for many years in achieving anterior correction. However, understanding the parameters of these systems is key to successful case selection and dental treatment. Even though there are several competing systems, they all base case selection on the same parameters. Understanding these systems can be crutial to your dental treatment planning.

Understanding the Clear Aligner Systems
First you must understand that clear aligner systems are best at correcting the centrals and laterals of either arch.  Cuspids are more difficult to move, therefore, realistic and very conservative cuspid correction must be undertaken.  Patients who have post-orthodontic relapse, untreated patients with mild to moderate anterior crowding or spacing, as well as patients in need of pre-restorative orthodontic improvement make best the candidates for these systems.

These treatment modalities are not meant as replacements for comprehensive orthodontic interventions.  Labial or lingual movement and tipping and rotations are commonly achievable, provided that space is made available to accommodate the new positions of teeth either through flaring/labial movement and/or interproximal reduction of anteriors. Other movements such as bodily transition of teeth mesially or distally, as well as root torque and vertical correction, are far more difficult and less predictable.

Additional tips
Bonded attachments may be beneficial for retention issues such as short clinical crown height, posteriorly or for the more challenging cases as their use improves capabilities considerably. Specific attachment shapes are placed on the selected tooth, and templates are provided for the user to replicate them clinically.

If interproximal reduction (IPR) is required, cards are provided upon receipt of the case. This data should be used judiciously and clinical IPR should be done incrementally to avoid over-reduction.

While case selection is critical, so is the management of the case in progress. Because of the many variables such as the degree of complexity of particular corrections, type, shape, and size of teeth as well as IPR, attachments, and patient’s compliance; the clinician should assess the completeness of correction at the end of each stage.

Each appliance in the system must remain in action until its job is done regardless of the estimated wear time. When this is not followed, the incomplete portion of correction gets passed on to the next appliances, possibly overburdening and overwhelming them. Ultimately, failure to achieve the predicted movements can be the result.

To ensure the overall success of these clear aligner systems, it is crucial to review wearing instructions and compliance requirements with the patient, and to closely monitor the progress the case. 
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