The Role of Temporary Anchorage Devices (TADs) with Clear Aligners

Introduction to Temporary Anchorage Devices (TADs) 

Temporary Anchorage Devices (TADs) are small screws placed in the jawbone that serve as anchor points for moving teeth. TADs offer a stable point of resistance enabling precise tooth movements. They are temporary and can be removed once the treatment is done.

The Role of TADs in Clear Aligner Treatments

TADs significantly enhance the efficiency of clear aligner treatments. They allow for controlled and targeted tooth movements for complex cases. Incorporating TADs in clear aligner treatments can allow for stubborn tooth movements that might otherwise require extended treatment times or invasive procedures. With CAT, there are numerous ways to attach elastics from TADs to the aligner. These include hooking the elastic from the miniscrew to a precision cut made on the aligner itself, attaching the elastic to a button bonded to the tooth surface with a cut-out made on the aligner to accommodate it or simply connecting the elastic to another miniscrew, allowing it to pass over the aligner.  

*It is important to note that the decision to incorporate TADs into a clear aligner treatment plan is entirely at the discretion of the treating orthodontist. These devices are independent tools that can complement clear aligner therapy, but their use and placement are based on clinical judgment and patient-specific considerations.

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Advantages of using TADs in Clear Aligner Treatments

Increased Control and Precision

The primary advantage of using TADs in clear aligner treatments is the increased control and precision in tooth movements. This level of control is difficult to achieve with clear aligners alone or with attachments.

Versatility in Treatment

TADs provide versatility in orthodontic treatment plans, allowing for a broader range of movements and corrections. They may be used to treat complex cases that may not be treated with clear aligners alone.

Minimal Invasiveness 

TADs are minimally invasive compared to other traditional orthodontic methods. The placement of the TADs is simple and can be done under local anesthesia in the same visit to the dental clinic.

Improved Retraction and Intrusion Capabilities 

TADs are effective for retraction and intrusion movements which are often challenging with clear aligners alone. They provide the necessary anchorage to retract anterior teeth or intrude over-erupted teeth making them ideal for deep bite cases.

Clinical Considerations
TADs Placement 

Successful integration of TADs begins with meticulous planning. It’s important to utilize advanced tools such as 3D imaging or digital scans to determine the optimal placement of TADs. They should be placed in areas with sufficient bone density to ensure stability and effectiveness. 

Care and Maintenance of TADs

Patients must consider following specific instructions to maintain the effectiveness of TADs. This can be done by ensuring proper oral hygiene including brushing and flossing around the TADs to prevent infection and ensure stability.

Integration with Treatment Planning 

Integrating TADs with treatment planning involves precise coordination with clear aligner protocols. Orthodontists should consider the sequence of tooth movements and the timing of the TAD placement to ensure optimal outcomes.

Monitoring and Adjustments

Continuous monitoring of TADs is important to evaluate their effectiveness and make any adjustments if necessary. This includes assessing anchorage status, checking for signs of inflammation and ensuring proper alignment with treatment goals.

‍The most frequently used TADs with clear aligners‍

Depending on the type of movement being planned, TADs may be used in various locations during clear aligner treatment. These locations may differ based on anatomical variations, but here are a few examples that may serve as general guidelines:

Buccal shelf TADs

These could be used when a considerable amount of distalization is being planned for the lower arch. The miniscrews are placed on the buccal shelf and an elastic may then be hooked from the miniscrew to a precision cut on the lower canine, reinforcing the planned distal movement.

Infrazygomatic crest TADs

These are useful for cases requiring a significant amount of distalization in the upper arch. Miniscrews are typically placed at an angle to the occlusal plane on the infrazygomatic crest as shown in the figure. Elastics are then extended to precision cuts on the labial surfaces of upper canines, reinforcing anchorage and aiding the movement.

Interradicular TADs

Interradicular TADs are those placed between the roots of teeth and could be used for a variety of movements, including intrusion of upper and lower posterior teeth, and the mesialization of lower molars. For intrusion of upper posterior teeth, they may be placed buccally between the roots of the upper second premolar and first molar with an elastic going over the aligner, then attached to TADs similarly placed palatally between the upper first and second molars. When the teeth being intruded are the lower posterior teeth, a miniscrew could be placed buccally between the lower first and second molars with elastics hooked from the screw to buttons on the buccal surface of each tooth (figure 1). As for the mesialization of lower molars, a miniscrew can be placed buccally between the lower canine and first premolar, with an elastic extending to a button bonded to a molar. (figure 2)

Between upper laterals & canines

Placing miniscrews between upper laterals and canines aid the intrusion of upper anterior teeth. Elastics may be hooked to either precision cuts on the palatal surfaces of anterior teeth or labially placed buttons.

Between lower canines & first premolars

When the teeth being intruded are the lower anteriors, miniscrews are placed between the canines & first premolars with elastics extending to labial buttons or lingually placed precision cuts.

Case Study by Dr. Salim Qadri

This patient presented to the clinic complaining of an open bite. Given the predictability of treating such cases with clear aligners and the patient wanting an aesthetic option, clear aligner therapy was the treatment modality of choice.

Since the patient had a significant open bite of about 5 millimeters on the lateral incisors and 2 millimeters on the centrals, a combination of anterior teeth extrusion and posterior teeth intrusion had to be done to achieve an almost normal overbite. Extrusive attachments were used to facilitate the extrusion of upper anterior teeth and interradicular TADs were used for a more predictable intrusion of upper posterior teeth. 

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As seen above, miniscrews were placed palatally between the roots of the upper right first and second molars and buccally between the roots of the upper right second premolar and first molar. On the upper left side, a miniscrew was placed palatally between the second premolar and first molar and another one between the two molars. In addition to an intrusive movement planned using aligners, elastics were extended from the buccal to the palatal TADs on each side to further aid the intrusive movement and achieve the desirable outcomes. 

Conclusion

Temporary anchorage devices can be real game-changers with clear aligner therapy. These minimally invasive auxiliaries enhance control, aid with challenging movements, and can be invariably used to achieve optimum results even with the least predictable cases.