Class II Diagnosis Treatment

This guide organises possible treatment options for a class II diagnosis. The document is a treatment planning tool to assist you assist how to best treat patients. Treatments are graded by complexity, ranked by the orthodontic technique required, as a guide to the efficacy of treatment and enable providers to select cases that best matches their ability to apply advanced techniques. In this regard, it is particularly useful for dentists who are just beginning to provide clear aligner treatment.

Disclaimer

As doctors are solely responsible for the treatment they’re providing their patients, they should understand their limits and not hesitate to consult a specialist for further guidance when required. Note when applying this guide only general, high-level information on how each isolated condition might be treated is provided. The relationships between different conditions that exist in the majority of patients are not addressed. In this regard, always consider each patient’s individual dental and periodontal condition, restorative needs, facial proportions, and age when considering treatment options.

Class II

Class II

The fit of the upper and lower first molars forms the cornerstone of the occlusion. An Angle Class II molar relationship exists when the mesio-buccal cusp of the upper first molar occludes mesial to the buccal groove of the lower first molar. Consequently, all the upper teeth tend to bite forward of their counterparts in the lower arch. The premolars and canines do not interdigitate correctly, and the upper incisors are too far ahead of the lowers. The anterior teeth have typically erupted into a deep overbite.

In most Class II malocclusions the upper incisors are proclined (leaning forward), resulting in a large overjet. These cases are classified as Class II division 1. In some Class II malocclusions the upper incisors are retroclined (leaning back), resulting in a near-normal overjet of just the central incisors. The lateral incisors, however, remain proclined. These cases are classified as Class II, division 2. Furthermore, there may be a difference in the molar relationship on the right side versus the left side. A case that is Class II on the right and Class I on the left is classified as a Class II subdivision right. Class II subdivision left occurs, when the unilateral Class II is on the left side. The upper and lower dental midlines typically reflect the underlying asymmetry in the molar relationship.

A Class II molar relationship can exist in varying degrees of severity. The discrepancy in the bite can range anywhere from 1–2 mm (mild Class II) to 3 mm (end-on Class II) to 6 mm (full cusp Class II), or greater. The effect on the occlusion of the anterior teeth varies accordingly, with greater overjet in the more severe Class II cases.

A Class II molar relation can have a dental and/or a skeletal basis. A dental Class II can exist, for example, when the upper first molars have drifted mesially after premature loss of the upper deciduous second molars. If the anterior teeth exhibit a large overjet, or if the upper incisors are leaning significantly backwards, the problem is typically skeletal in nature. A lateral cephalometric headfilm can be used to confirm the contribution of the skeletal component to the sagittal diagnosis. In the absence of a lateral head- film, the profile photograph gives a rough indication of the relative size of the upper and lower jaw. Patients that are skeletally Class II tend to have a convex profile, with a retrusive lower jaw.

When treating Class II malocclusions, the age and growth potential of the patient is a primary diagnostic variable. In the growing patient, the Class II may be correctable by growth modification treatment. A wide variety of orthodontic treatment choices exist for correcting a Class II, such as a headgear, Herbst appliance, twin block appliance, and Bionator. The goal of this initial treatment phase is to turn the Class II malocclusion into a Class I malocclusion. Correction of the alignment problems is much simpler once the sagittal problem has been resolved.

The treatment of the non-growing adult Class II case will primarily depend on whether correction of the underlying skeletal discrepancy is desired, or if a dental camouflage solution is adequate to satisfy the patient’s concern(s). If correction of the skeletal discrepancy is desired, an orthognathic surgical solution is most common. If dental camouflage is acceptable, the orthodontic solution may entail bicuspid or other extractions, enamel reproximation, or possibly even aesthetic dental alignment without additional change to the posterior bite relationship.

Dental (End-on Class II)

Maintain Class II, aesthetic alignment Novice (0-15 cases)

Maintain the molar and canine Class II relationships and only align the anterior teeth to improve the aesthetics, leaving an anterior overjet. Long term retention is especially important when leaving anterior overjet to help avoid relapse.

Digitise, Class II elastics as needed Experienced (16-50 cases)

Distalisation of the upper posterior teeth, using Class II elastics as needed to support the anchorage and retracting the anterior teeth to achieve a Class I canine relationship and a good anterior overjet. Distalisation cases take longer than the average Proligner treatment due to the reduced number of teeth moving at any given stage; as a result, patient cooperation and motivation is especially critical for treatment success. When distalising upper molars, the first point of contact in the posterior occlusion may become more pronounced, so equilibration may be needed at the end of the treatment to prevent the patient from pivoting around this point.

IPR canine to molar Experienced (16-50 cases)

Leaving the molars in Class II and doing posterior reproximation (distal of canine to molar) as needed to improve the canine relationship. Anterior reproximation may also be needed to improve the final overjet. Completing posterior reproximation prior to taking the PVS impression is recommended for maximum accuracy and optimal aligner fit.

Extraction, Proligner treatment with auxiliaries and/or fixed Advanced (>50 cases)

Extraction of two upper bicuspids or two upper and two lower bicuspids, using Proligner with auxiliaries as needed and possibly combining it with fixed appliances to finish the treatment. This setup should only be attempted by expert clinicians with experience in both Proligner and fixed appliances. The goal of this treatment is to achieve Class I canine relationship and full Class II molar relationship, with optimal overbite and overjet.

Skeletal

Maintain Class II, aesthetic alignment Novice (0-15 cases)

If orthognathic surgical correction of the skeletal Class II problem is declined by the patient, aesthetic alignment may be an option. Maintain the molar and canine Class II relationships and only align the anterior teeth to improve the aesthetics, leaving an anterior overjet. However, long term retention is especially important when leaving anterior overjet to help avoid relapse.

Improve Class II with digitisation, Class II elastics and/or IPR as needed Experienced (16-50 cases)

Distalisation of the upper posterior teeth to improve the Class II molar relationship, using Class II elastics to support the anchorage and/or doing posterior reproximation (distal of canine to molar) as needed to improve the canine relationship and anterior reproximation as needed to improve the final overjet. Distalisation cases take longer than the average Proligner treatment due to the reduced number of teeth moving at any given stage; as a result, patient cooperation and motivation is especially critical for treatment success.

IPR canine to molar Experienced (16-50 cases)

Leaving the molars in Class II and performing posterior reproximation (distal of canine to molar) as needed to improve the canine relationship and anterior reproximation as needed to improve the final overjet. Completing posterior reproximation prior to taking the PVS impression is recommended for maximum accuracy and optimal aligner fit. Long term retention is especially important when leaving anterior overjet to help avoid relapse.

Pre-surgical Proligner alignment followed by surgery Advanced (>50 cases)

Pre-surgical Proligner treatment to align and coordinate the arches for orthognathic surgical correction of the skeletal Class II problem. Fixed appliances are usually placed immediately prior to surgery for interarch fixation, and a stainless steel archwire bent to fit the brackets in a passive manner. The case may be finished post-surgically using the fixed appliances, or by using Proligner refinement aligners.

Extraction, Proligner treatment with auxiliaries and/or fixed Advanced (>50 cases)

Extraction of two upper bicuspids or two upper and two lower bicuspids, using Proligner with auxiliaries as needed and possibly combining Proligner treatment with fixed appliances to finish the treatment. Due to the long span of tooth movement required, this type of treatment should only be attempted by expert clinicians with experience in both Proligner and fixed appliances.