Orthodontic Treatment for Class III Malocclusion and anterior cross bite using WhiteSmile Clear Aligner

by Dr. Kamsiah G Haider, Dr. Liyana Aminuddin

June, 15 2022

As the demand for aesthetic treatments is increasing, more people are seeking alternatives to conventional fixed orthodontic appliances. Clear aligners are an aesthetic and comfortable option for orthodontic treatment and have gained immense popularity over the last decade. 

Developments in clear aligner technologies have increased the number and complexity of cases treated with this method. Clear aligners provide an aesthetic and comfortable treatment experience, facilitate oral hygiene, cause less pain as compared to fixed orthodontic appliances, reduce the number and duration of appointments. 

Aligners have been evolving for years. In the beginning, they could only treat mild malocclusion cases. Considerable effort explored the possibilities and limitations of aligners, aligners combined with Class III intermaxillary elastics is quite common. 

Despite the alterations in the shape of the aligner, movements such as root paralleling, extrusion, and rotation can be achieved using smart force attachments. These attachments are small composite bulges designed to produce a force system favourable for the designed movement. Their position and shape are determined to the desired movement. Extrusion and rotation attachment, and root control attachments are currently used. Extrusion of a single tooth is moderately difficult using clear aligners when compared to fixed-appliance systems, however, some auxiliaries such as buttons and elastics can be used to facilitate this movement. 

This case describes the non-surgical treatment of a 15-year-old girl with Class III malocclusion with Class III skeletal pattern. She presented with moderate to severe crowding, partially erupted tooth 23. The treatment objectives were to correct the crossbite and align the upper and lower midlines. The patient refused any extraction and surgery if possible. No temporary anchorage device (TAD) was placed.

At the beginning of the treatment

The patient correctly wore the aligners for almost 24 hours a day except during meals and teeth brushing. Important stages of treatment mechanics involve appropriate labial root torque for palatally displaced teeth as well as buccal root torque of posterior teeth to avoid lateral open bites. After 12 months of treatment, the patient had improved the malocclusion, a positive anterior overjet, and improved upper and lower alignment. At the end of the first phase of treatment, slight refinement was required as the upper right canine was not extruded to the ideal position. Button was placed at the cervical of upper right canine and lower right canine. Patient was advised to wear elastic from the buttons at upper right canine and lower right canine to extrude the upper right canine to its ideal position for 2 months. ( Photo 2 )

A few months later, the patient consolidated the molar and canine class I relationship, achieved a positive overjet and overbite and resolved midline misalignment. The patient was well satisfied with her aesthetic and functional occlusion. The Class III malocclusion was successfully resolved with lower molar distalization, retroclination of lower incisors and proclination of upper incisors to improve overjet and overbite and correct class III. At the end of the refinement phase, the patient was required to wear a long-term upper and lower Essix retainer for 24 hours except during eating and toothbrushing for the first 6 months. After 6 months, patient was required to the retainer at night only.

In summary, this case illustrates that challenging cases may be treated with clear aligners but with the correct delivery of forces applied to a clinically valid, composite aligner material (such as the Tristar aligner material) as well as a compliant patient. Doctors and patients are set to reap the advantages of clear aligner treatment results which has improved significantly over the last decade.


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