Understanding the Limitations of Clear Aligners

What Our Catford Patients Need to Know.

Dr O Dadashian

When considering clear aligners for your orthodontic treatment, it's crucial to understand not just their strengths, but also their limitations. While these innovative devices have revolutionised orthodontic care, scientific research has identified specific challenges in certain types of tooth movements. Let's explore these limitations to help you make an informed decision about your treatment.

The Challenge of Moving Teeth Outward (Extrusion)

One of the most significant limitations of clear aligners involves moving teeth outward from the gum line, technically known as extrusion. Research shows this is actually the least predictable movement, with success rates as low as 30%. For front teeth, the numbers are even more modest:

• Upper front teeth: Only 18% successful extrusion

• Lower front teeth: About 25% successful extrusion

Why is this important? If your treatment plan requires significant outward movement of your front teeth, your local Catford dentist might need to consider alternative approaches or combine clear aligners with other techniques to achieve the desired results.

Rotation Control: The Round Tooth Challenge

Rotating teeth into proper alignment presents another interesting challenge for clear aligners. The research reveals some important findings:

• Overall rotation accuracy: About 36% for canine teeth

• Better results with IPR (Inter-Proximal Reduction): 43% accuracy

• Significantly reduced effectiveness for rotations over 15 degrees

• Best results when limiting movement to less than 1.5 degrees per aligner

Think of it like trying to grip a smooth, round surface - it's naturally more challenging. This is particularly true for canine teeth, which have a rounded shape. Your orthodontist might need to use special attachments or additional techniques to achieve the desired rotational movements.

Controlling the Tilt: Buccolingual Inclination Challenges

The third significant limitation involves controlling the inward or outward tilt of teeth (buccolingual inclination). This movement requires precise control and often proves challenging with clear aligners alone. Research indicates:

• Overall accuracy rates around 41%

• Best performance in lower side teeth (49%)

• Less predictable results in canine teeth (27%)

Making Clear Aligners Work Better

Despite these limitations, there are several ways to improve the effectiveness of clear aligner treatment:

1. Strategic Use of Attachments

Adding small tooth-coloured bumps to specific teeth can significantly improve the aligner's grip and control over tooth movement.

2. Proper Treatment Planning

Breaking down complex movements into smaller, more manageable steps can help achieve better results.

3. Patient Compliance

Wearing aligners for the recommended 20-22 hours per day is crucial for success.

When to Consider Alternative Options

You might want to discuss alternative treatment options with your orthodontist if your case involves:

• Severe rotations (especially over 15 degrees)

• Significant extrusive movements needed

• Complex buccolingual inclination changes

• Multiple challenging movements combined

Making an Informed Decision

Understanding these limitations doesn't mean clear aligners aren't right for you. Rather, this knowledge helps set realistic expectations and allows for better treatment planning. Your orthodontist might recommend:

• A combination approach using different techniques

• Modified treatment timelines

• Additional attachments or auxiliaries

• Alternative treatment options where appropriate

The key to successful orthodontic treatment lies in proper case selection and realistic expectations. By understanding both the capabilities and limitations of clear aligners, you and your orthodontist can make informed decisions about your treatment path.

References:

1. Rossini G, Parrini S, Castroflorio T, Deregibus A, Debernardi CL. Efficacy of clear aligners in controlling orthodontic tooth movement: A systematic review. Angle Orthod. 2015;85(5):881-889.

2. Galan-Lopez L, Barcia-Gonzalez J, Plasencia E. A systematic review of the accuracy and efficiency of dental movements with Invisalign®. Korean J Orthod. 2019;49(3):140-149. 3. Robertson L, Kaur H, Fagundes NCF, Romanyk D, Major P, Flores Mir C. Effectiveness of clear aligner therapy for orthodontic treatment: A systematic review. Orthod Craniofac Res. 2020;23(2):133-142.