Question:

Is there any training or info on the new twin block system?

Answer:

Mandibular Advancement Occlusal Blocks

The Mandibular Advancement Occlusal Blocks are an orthodontic feature that is becoming available to practitioners as an alternative to the traditional mandibular advancement methods. These blocks are used to treat patients with malocclusions, specifically Class 2, Division 2 occlusion, by promoting the repositioning of the jaw and improving the bite. Below is an overview of the clinical use and application of these blocks.

Clinical Application and Setup

Mandibular advancement is typically indicated for patients with retrognathic mandibular profiles, meaning their lower jaw is positioned further back relative to the upper jaw. A common example is a Class 2, Division 2 malocclusion, where the patient's mandibular growth is restricted, and there is a deep bite.

When using the occlusal blocks, the initial step in treatment involves proclining the patient’s teeth to start creating space for mandibular repositioning. This helps to initiate a forward posture of the jaw. The occlusal blocks themselves are placed on the trays for both the upper and lower arches. These blocks serve the purpose of holding the patient's jaw in a more forward posture, which can help correct the deep bite and address issues associated with Class 2, Division 2 occlusion.

Advantages of Occlusal Blocks

The primary advantage of using mandibular advancement occlusal blocks over traditional mandibular advancement wings is that these blocks allow for attachments on the buckle of the lower molars. In contrast, the mandibular wings prevent the placement of attachments on posterior teeth, which are essential for proper bite correction. The occlusal blocks help lock the trays in place and provide better control over the bite correction process.

The blocks allow for more precise and effective treatment in cases of deep bite correction, especially when the patient’s mandibular growth is restricted. The use of these blocks also provides the benefit of more controlled mandibular repositioning. This method is particularly useful in younger patients, where promoting mandibular growth is a primary goal.

Treatment Considerations and Challenges

The mandibular advancement occlusal blocks are designed to prop the patient's jaw forward, but this can result in the patient feeling slightly "propped open." This issue arises due to muscle splinting, where the muscles around the jaw may resist the new positioning, leading to temporary discomfort. However, this is usually temporary and does not necessarily indicate relapse.

As the treatment progresses, practitioners may notice that patients occasionally return to their initial bite position due to muscle splinting. For instance, patients may present with an edge-to-edge bite on their canine teeth, but this does not mean the treatment has failed. The muscle resistance can be overcome with continued use of the occlusal blocks and, if necessary, the introduction of elastics to help fine-tune the correction.

Case Studies

In one case, a patient with a super retrognathic mandible and a Class 2, Division 2 malocclusion presented with a slight notching of the cervical vertebrae, indicating that their growth was nearing completion. The use of occlusal blocks was initiated after proclining the teeth, and the patient showed gradual improvement in mandibular positioning. However, early in the treatment, the patient experienced tracking issues with the trays, which was not a significant concern as it was addressed with a new set of trays.

As the treatment progressed, the patient’s mandible began to shift forward, and the occlusion improved. The patient’s bite, while still presenting some mild class 3 characteristics on the canine teeth, showed improvement overall. Muscle splinting was noted as a potential cause for the slightly misaligned bite, but this was expected to resolve with continued treatment.

Another case involved a younger female patient with a smaller mandible who presented with a similar malocclusion and was treated with mandibular advancement occlusal blocks. This patient had a square vertebrae and slight notching, indicating that growth was still ongoing. The blocks were applied immediately, and despite initial concerns about edge-to-edge biting on her canines, the issue was attributed to muscle splinting rather than relapse. At the end of the first aligner set, the patient was successfully transitioned to more refined control using elastics.

Final Adjustments and Fine-Tuning

The use of occlusal blocks helps achieve the gross movements necessary for mandibular repositioning, but finer control over occlusion can be achieved through the use of Class 2 elastics at the later stages of treatment. Elastics help refine the alignment and ensure a more precise correction of the bite, particularly in cases where the mandibular advancement needs fine-tuning.

The overall treatment philosophy with mandibular advancement occlusal blocks is to begin with the blocks to initiate jaw repositioning and control gross movements, and later use elastics for detailed adjustments. This approach is applicable to both younger patients who require growth guidance and older patients who need more refinement of their occlusion.

Conclusion

The Mandibular Advancement Occlusal Blocks are a valuable tool for orthodontists treating Class 2, Division 2 malocclusions, as they provide a more controlled method of mandibular repositioning and bite correction. These blocks allow for the use of attachments on the posterior teeth, which is crucial for controlling the deep bite and locking the trays in place. While the initial discomfort from muscle splinting may occur, this typically resolves over time. Overall, the use of occlusal blocks in conjunction with elastic adjustments offers a comprehensive treatment option for patients requiring mandibular advancement.