Many patients present to an orthodontic office with some degree of Class II malocclusion. The treatment approach for correcting a Class II malocclusion depends on various factors, including the type and degree of skeletal dysplasia, facial profile, remaining growth, anteroposterior molar and canine relationship, degree of crowding, malposition or malformation of teeth, patient compliance, and the patient’s acceptance of the treatment plan. This blog will focus on one particular means of Class II correction: dental camouflaging with maxillary premolar extraction.
Choosing an Appropriate Patient
Dental camouflaging by definition is a compromise. The orthodontist is knowingly retracting and retroclining the maxillary anterior dentition into a less than ideal cephalometric position to achieve acceptable overjet and improved smile aesthetics. An appropriate patient to receive this treatment may present with one or more of the following characteristics: refusal of orthognathic surgery, maxillary hyperplasia, moderate retrognathia with an acceptable facial profile, greater than 50% Class II canine, aversion to a Class II corrector, ectopic maxillary canines or premolars, presence of maxillary third molars, lower incisor proclination, compromised periodontal health, treatment-duration restraints, or a metal allergy (Figure 1).
Among the many diagnostic tools I use during an orthodontic consultation in my office, I pay particular attention to canine relationship when determining treatment modality. After all, canine Class I, not simply molar Class I, is my primary objective. In the absence of a Bolton Discrepancy or missing teeth, canine Class I occlusion ensures appropriate overjet and coinciding dental midlines. Furthermore, if the canines are in proper occlusion, often the posterior teeth follow. If the canines are less than 50% Class II occlusion, I am confident that I can achieve ideal occlusion with orthodontic elastics. If the patient presents with greater than 50% Class II occlusion, I may favor bicuspid extraction or a mandibular advancing appliance.
In my office, I enjoy using a variety of mandibular advancing appliances to provide Class II correction. The one key determinant when presenting maxillary premolar extraction as a more appropriate treatment alternative is lower incisor angulation. Fixed Class II correctors that reduce overjet by mandibular advancement, such as the Herbst appliance, MARA®, Crossbow®, and Forsus Fatigue Resistant Springs®, always provide some degree of mandibular incisor advancement. Therefore, in the absence of severe crowding and periodontal attachment loss, when using such appliances I prefer my patient’s pretreatment incisor inclination to be less than 105ยบ. Mandibular advancing appliances used in the presence of mandibular incisor proclination will result in incisor dumping, attachment loss, and creation of an anterior open bite, regardless of whether there is labial support (Figures 2 and 3).
Choosing Between First and Second Bicuspids
Choosing between extracting the maxillary first or second bicuspids depends on the severity of pretreatment overjet, anchorage requirements, aesthetic demands, tooth position, and presence of restoration or caries. Commonly, the maxillary first premolars are extracted to allow for maximum retraction of the anterior teeth with minimal anchorage loss or correction of an ectopic maxillary canine. For example, I might choose extraction of the maxillary first premolars if the patient presents with a greater than 75% canine and molar Class II malocclusion with severe overjet and healthy second premolars.
However, I might favor extraction of the maxillary second premolars if the presenting overjet is less severe and anchorage requirements are lower, or if these teeth are palatally ectopic, severely malrotated, or have a large restoration or root canal treatment (Figure 4).
Also, extraction of the second premolars may be favorable if the patient is concerned with the visibility of extraction spaces during the consolidation phase. In patients receiving maxillary lingual braces, extraction of the maxillary second premolars rather than the first premolars was traditionally encouraged. The thought was that wire engagement and sliding mechanics might be easier if the extraction spaces were further from the “mushroom” bend of the lingual archwire. However, with the advancement of custom-lingual brackets, this archwire bend has been eliminated altogether.
In my office, maxillary premolar extraction is a valuable, efficient, and stable treatment alternative for correcting a Class II malocclusion in patients who present with greater than 50% canine Class II occlusion, lower incisor proclination, and aversion to orthognathic surgery or a mandibular advancing appliance.
Neal D Kravitz, DMD, MS is a Diplomat of the American Board of Orthodontics. He is also clinical faculty at the University of Maryland and Washington Hospital Center. Dr. Kravitz received his undergraduate degree from Columbia University and his DMD at the University of Pennsylvania. A prolific writer, Dr. Kravitz currently serves on the editorial review board for seven refereed professional journals. Dr. Kravitz maintains two thriving offices in South Riding, VA and White Plains, MD.
