Class II Flashcards

Question

# Expert's Perspective!!! NOT PROTOCOL There are several additional benefits for using Carriere Distalizer prior to Invisalign treatment:

Answer 1

**First**, the most difficult problem to correct in the malocclusion is addressed and corrected initially. Elastic wear is completed in the first phase of treatment, as elastics are usually not needed while wearing aligners in the second phase of treatment. This eliminates any question of whether the molar relationship will be fully corrected by the time the teeth are well aligned. **Second**, the distalizer has shown the ability to correct sagittal discrepancies beyond what can be achieved by using aligners and elastics alone. Thus, adding the Carriere Distalizer to the treatment protocol **expands the number of patients** that can be effectively treated with the Invisalign system. **Third**, the doctor has an early chance to measure patient **compliance**. If a patient fails to wear elastics for the short duration with the Carriere Distalizer, chances increase this patient will not demonstrate good compliance with the Invisalign treatment. **Finally**, **treatment time is generally less** as a result of the rapid correction of the molar relationship, which the patient can appreciate in the early stages of treatment.

Answer 2

Aligners effectively close the small spaces often present around the maxillary anterior teeth. Taking a panoramic x-ray following removal of the distalizer will provide specific details on root movement corrections that need to be verified in the ClinCheck Treatment Plan. Attachment design is important and there are some basic principles. Always keep and use Optimized Attachments whenever possible. In all instances, Optimized Attachments are the best available for the crown and root movement depicted in the ClinCheck Treatment Plan. If Optimized Attachments are located on upper cuspids, then the first bicuspids make a reasonable location for Precision Cuts. While Class II elastics are not indicated in many cases following distalizer completion, it doesn’t hurt to plan for their addition should the need arise. Retention attachments, 4x2x1 mm horizontal beveled attachments or similar, are usually requested on one molar in each quadrant. When a Precision Cut hook is added to a lower molar, a 4x2x1 retention attachment is added to the tooth mesially per Align’s protocol — this will only happen if the lower molar does not have any other attachment. These attachments are required to maintain aligner stability when wearing any Class II elastics. In addition, poor or loose fitting aligners will not be worn as much as well-fitting, retentive aligners, thus decreasing the overall treatment effectiveness. A final, but important ClinCheck Treatment Plan factor involves posterior vertical changes. Molar teeth, especially upper second molars, should not be extruded. A great advantage of Invisalign treatment is the ability to limit the passive vertical eruption of the molar teeth. In growing patients this can translate into a counter-clockwise rotation of the mandible and enhance the sagittal position of the mandible. This is a big plus trying to maintain the molar relationship that was established by the Carriere Distalizer in the first phase of treatment. The retention protocol following the second phase of treatment consists of placing a bonded lower lingual retainer and a maxillary full coverage Vivera or Essix-type thermoplastic retainer. The upper retainer is worn full time for 90 days, then nights only from that point on.

Answer 3

Adequate explanation of the benefits of combination treatment requires patient education prior to starting treatment. When the patient and parent(s) understand how each appliance functions, then they buy-in to the rationale for combination treatment. Patients are asked if they would prefer wearing elastics with the Carriere Distalizer for the first 4 months of treatment to correct the most difficult part of their treatment, as opposed to wearing Invisalign aligner and elastics for the entire treatment. Invariably, this puts things in perspective and they understand the efficiency and effectiveness gained by using the combination approach with the Carriere Distalizer. More importantly, the patient begins to accept ownership and responsibility for the success of their treatment. Their cooperation is the key to achieving the best possible result.

Answer 4

Orthodontic correction of a mild to moderate Class II malocclusion with the Invisalign system may be handled both predictably and efficiently. When correcting a unilateral or bilateral Class II dental malocclusion, it is important to carefully evaluate the etiology of the Class II relationships. Dr. Mazyar Moshiri generally considers the following four variables below, in priority. Correction of mesial rotation of the maxillary molars tops this list. It has been shown that up to 85% Class II patients have mesial rotation of their maxillary 1st molars.**1 One cause for displacement of the molars is mesial movement into the leeway space left during transition from mixed to permanent dentition. This creates a loss of arch length and resultant mesial version of the remaining dentition anteriorly, creating a Class II cuspid relationship and increased overjet.** Any further mesial drift from anterior crowding and/or arch constriction further exacerbates this problem. Correction of molar rotation not only helps to classify the molars into a Class I relationship, but simultaneously opens room for subsequent distalization and Class I correction of the remaining buccal dentition.

Answer 5

Request the buccal surfaces of the upper molars to be near parallel to each other on the ClinCheck Treatment Plan. Due to the rhomboidal shape of the upper first molars, correction of mesial rotations may open up to 2 mm of space per side for subsequent distalization of bicuspids and cuspids. The decision to use a vertical attachment per molar, beveled towards the direction of movement (distal), will depend on whether additional distalization of the molars will also be required, in combination with rotation correction, as outlined below. However, it is known that rotation of the molars with aligners alone is a predictable movement.

Answer 6

1. Are there mesial-in rotations of the upper molars, especially the first molars? 2. Upon correction of molar rotations, is distalization required to achieve ideal Class I molar occlusion? 3. How much expansion is necessary to further gain space for distalization and Class II correction of the remaining buccal segments? 4. Is there a Tooth Size Discrepancy (TSD), and can this be used to aid in correction of the malocclusion?

Answer 7

Based on the buccal relationships achieved after correction of molar rotations, sequential distalization may be achieved by using the force of the aligners and Class II elastics to “push” the molars into a Class I relationship, with the distal cusp of the maxillary first molar matching the embrasure of the mandibular first and second molars. Dr. Moshiri does not routinely attempt more than 2 mm of sequential distalization with aligners. For this type of distalization, it is important to have an attachment on the maxillary second molar to initiate this movement. Ask for distalization movements to be delayed until attachments have been bonded on the teeth if your Clinical Protocols place attachments at later stages. Additional attachments may then be placed on every other tooth up to the cuspids, in order to make appliance removal amenable to the patient. If a patient has maxillary 3rd molars present, ask for their extraction after the patient has their impressions/scan to take advantage of the inflammation and space created. Once the buccal occlusion is nearly seated into full Class I on the ClinCheck Treatment Plan, Dr Moshiri asks for retraction of the 2-2 segment with additional lingual root torque to achieve proper overbite and overjet.

Answer 8

Generally speaking, Class II malocclusions have a relative maxillary transverse discrepancy relevant to the mandibular arch. According to the aforementioned mechanics needed for Class II correction, the maxillary teeth need to be directed towards a wider part of the arch during treatment. Given the advances in tooth movement with the Invisalign appliance, we know that in most scenarios it is more efficient to combine movements to decrease treatment time and increase predictability of the treatment outcomes. Practitioners should aim to see on their respective ClinCheck Treatment Plans simultaneous distal rotation, expansion, and distalization of the molars. Ask patients to use aligner chewies 10 minutes per day posteriorly during these movements to help seat the aligners properly. Regarding the total amount of expansion needed, Dr. Moshiri asks for 2 mm of buccal overjet on all teeth and DOES NOT like to see a “socked-in” occlusion at the end of the ClinCheck Treatment Plan. The reasoning behind this preference is that the amount of expansion indicated on the ClinCheck Treatment Plan may not express clinically, especially when using a lot of Class II elastic wear, which has a constrictive force on the maxillary arch.

Answer 9

Undiagnosed Tooth Size Discrepancies (TSD) are a major reason for occlusal instability and poor treatment outcomes. This information is easily attained from your technician, and is crucial for detailing the occlusion and treatment success. Given your patients’ anterior esthetics (i.e. small upper laterals), buccal occlusion, depth of bite, etc., any existing Tooth Size Discrepancy may be used to the clinicians’ advantage to further treat a Class II malocclusion predictably. For example, if at the end of the ClinCheck Treatment Plan the patient is still Class II in the premolar and canine areas, and there is a maxillary excess indicated on the TSD analysis, then this may be used to help address any remaining space and distalization needed to seat the patients’ buccal occlusion into full Class I. As another example, commonly mandibular excesses will be noted. In this scenario, IPR may be used for mesialization of the lower dentition with Class II elastics to further aid in Class I correction and establishment of proper overbite and overjet.

Answer 10

There are many different methods of correcting Class II malocclusions in orthodontics. The first step in deciding which method is appropriate for any given patient is records and diagnosis of the malocclusion. The Invisalign system is my appliance of choice in Class II cases where the sagittal discrepancy is up to approximately 3.5 mm (Ref. 1) and the decision is to correct the discrepancy completely by a combination of distal movement of the maxillary arch and/or mesial movement of the mandibular arch supported by Class II elastics. The Invisalign system offers the advantage of improved posterior vertical control and avoidance of undesired mandibular posterior extrusion which could lead to down and back rotation of the mandible increasing the Class II discrepancy. Here are my techniques for Class II correction with the Invisalign system using the Class II Elastic Simulation (also known as bite jump) in the ClinCheck Treatment Plan to simulate sagittal correction.

Answer 11

The treatment goal includes alignment and leveling of the upper and lower arches. Depending on the severity of rotations, Crowding or Spacing, Curve of Spee, anterior torque and other individual characteristics of the malocclusion, many different features will appear in the ClinCheck Treatment Plan, including Optimized Attachments. Each arch will be aligned individually in the ClinCheck Treatment Plan during this initial alignment phase. In this technique of ClinCheck set-up there is no need for significant distalization of the upper posterior teeth or mesialization of lower posterior teeth during the alignment phase of the ClinCheck Treatment Plan. There is an advantage to activating the periodontal ligaments of the upper molars by mesial-buccal rotation of the upper first molars and minimal movement of the upper second molars to allow the upper molars to rotate in distal direction about the large palatal root of the upper molars (Ref. 2). The activation of these periodontal ligaments will aid in the clinical distal movement of the upper molars from the distally directed forces to the upper aligners from the Class II elastics. The Class II relationships will remain present in the ClinCheck Treatment Plan during this phase although improved by molar rotations (Ref. 3).

Answer 12

Since Class II elastics will be required during the alignment phase of the orthodontic treatment, my preference is to place Class II elastic hooks on the aligners on the upper cuspids, and cut-outs for buttons on the mandibular second molars (Precision Cuts) (Ref. 4). Aligners provide excellent posterior control against extrusion of posterior teeth, and the advantage of having Class II elastics from upper cuspids to lower second molars allows for increased horizontal vector of the elastic force without the disadvantage of extrusion of lower second molars. This vertical control offered by the Invisalign system often leads to shorter treatment times with elastic wear. In anticipation of the dislodging effect of the elastics on the aligner in the upper anterior area, some attachment should be present (on first bicupids, cuspids or lateral incisors) to aid in maintaining retention of the aligner on the teeth in the upper cuspid area. By default, the Molar Precision Cut protocol will place a retention attachment on the tooth mesial to the hook unless there is already an attachment placed there to address another movement, i.e. bicuspid rotation.

Answer 13

At the end of alignment of the arches, a ‘Class II correction elastic simulation’ on the Invisalign Prescription Form is programmed to show the repositioning in ideal Class I posterior relations (Ref. 5). This sagittal bite jump represents the Class II clinical effects of Class II elastic wear. As in any orthodontic correction by elastic wear, the correction occurs over the treatment time. The patient will be using elastics throughout the treatment, and as alignment is progressing in earlier aligners, the doctor checks molar relationships to ensure the molars are translating to a Class I relation. The sagittal correction of molar relations will often take place well before the completion of all aligners, and the patient can then be instructed to wear less elastics. As in all orthodontic treatment, this progress is monitored during treatment by the orthodontist and instructions for either more or less elastic wear is decided by the orthodontist throughout the entire treatment time. Note that the number of aligners is driven by the tooth movements programmed, not by the expected time the elastics might need to do the A-P correction.

Answer 14

The nature of orthodontics has always depended upon patient cooperation and the orthodontist’s ability to assess progress and then adapt orthodontic forces to the dentition to detail the finish for the individual patient. The refinement stage of Invisalign treatment is an opportunity for the orthodontist to do just that. Depending on patient cooperation with and clinical response to Class II elastics and aligner wear, the patient may have an occlusal relationship that exactly matches the ClinCheck Treatment Plan, or on the other hand it would be expected that there may be some small differences as in any other orthodontic plan. At this time, the clinician can order refinement to detail the occlusion.

Class II Flashcards

(38 cards)