Anterior Intrusion With Clear Aligners
Restoring a deep Class II bite without compromising function and esthetics
Andrew Ferris, DDS, MS
Deep bites, which are very commonly seen in practice, can develop for a number of reasons, but oftentimes, patients present with a lack of coupling due to a Class II dental or skeletal malocclusion. This can result in super eruption of the anterior teeth and create challenging situations for clinicians. Research shows that deep bites can cause pathway interferences due to a restriction in the envelope of function, which can lead to accelerated attrition. Deep bites can also increase the load on the temporomandibular joints and affect overall function. Although there are several treatment options that can be presented to these patients, including traditional orthodontics, clear aligners can be an effective appliance to correct this type of malocclusion when correctly designed.
A 57-year-old female patient presented to the office with severe malocclusion. She had a deep bite of greater than 100% that was impinging on the palate as well as severe crowding in her anterior mandible. In addition, she had a multitude of other health conditions, including severe intraoral scarring due to prior ingestion of a caustic substance. An initial cone-beam computed tomography (CBCT) scan was acquired during the examination.
Developing an orthodontic treatment plan was challenging due to the patient's severe amount of mandibular crowding and severe two-plane occlusion. It would have been easy to justify premolar extractions; however, she was brachyfacial, and this approach would have compromised her function and the appearance of her profile. Furthermore, the use of traditional fixed appliances would have been very challenging in this situation due to the severe two-plane occlusion and crowding. The path of least resistance would be in the anterior direction, which could result in severe proclination and compromise the incisors. Therefore, clear aligner treatment (Invisalign®, Align Technology) was used to fully intrude the lower anterior teeth while developing the arch forms in order to create space to align the teeth and finish with a healthy functional occlusion. The treatment was enhanced by daily use of a device that delivers micropulsed vibrations to accelerate tooth movement (AcceleDent Aura®, OrthoAccel Technologies, Inc).
During treatment, the patient decided to purchase a low-level laser therapy device online and switch aligners every five days to further accelerate the treatment. Although this was not recommended, within less than 6 months, her lower anterior teeth had intruded approximately 6.6 mm. This shows how powerful clear aligners can be as a tool, even in treating the most complex cases.
The final result of intruding the lower incisors was a level occlusal plane. A final CBCT scan was acquired and compared with the initial CBCT scan, and measurements were made from the incisal edges of the mandibular anterior teeth to the border of the mandible and from the occlusal surfaces of the premolars to the border of the mandible. After 50 weeks of treatment, the mandibular incisors had been intruded by approximately 8 mm with insignificant extrusion of the posterior teeth. As a part of the treatment, teeth Nos. 24 and 25 were differentially intruded in order to create the space necessary to restore the exposed dentin, and a lingual wire (Retainium, Reliance Orthodontic Products) was placed in the anterior mandible for retention. The patient continued to follow-up over the next 5 years to ensure stability.
About the Author
Andrew Ferris, DDS, MS
Loma Linda University
School of Dentistry
Loma Linda, California
Santa Barbara, California