Invisalign®’s Mandibular Advancement appliance: A guide

Does your child/teen’s lower jaw appear retrusive and sit too far back?Do their front teeth appear more protrusive? If so, you might have heard about functional appliances such as the Twin Block or the newest appliance in the Invisalign® appliance range, the Invisalign® with mandibular advancement or Invisalign® MA. Each of these orthodontic appliances are designed to help correct these dento-facial issues but first, a small introduction:

What is Invisalign® MA?

This innovative Invisalign® appliance is for growing children/teens who need their retrusive lower jaw to be gently encouraged to grow forwards which not only aids to help improve facial balance, it also helps correct protrusive front teeth.

The aligners are the same as traditional Invisalign® aligners but have built-in ‘precision wings’ – small, smooth ‘ramps’ at the back of each upper and lower aligner which sit just inside the cheek.When the mouth closes, the upper and lower wings engage to guide the lower jaw into a slightly forward position and over time, this helps the correct the bite, correct the protrusive teeth and improve facial balance. At the same time the bite is correcting, the teeth are also straightening which overall, makes Invisalign MA a very efficient appliance!

Pros:

• Discreet: Clear and barely noticeable
• Comfort: Low profile with no bulky acrylic plates. Easy to speak
• Easy Cleaning: Removable for brushing
• Efficient: Allows incremental jaw advancement and teeth straightening at the same time
• Fewer Breakages: No metal wires to break

Precision wings vs occlusal blocks:

Introduced in 2025, the Invisalign® MA with occlusal blocks (MAOB) is the latest innovation to replace the precision wings. Solid bite pads are laser welded onto the aligners and when engaged, incremental advancement of the lower jaw begins. The occlusal blocks are more robust and durable and can resist the crushing forces of the bite. The MAOB is especially effective in treating growing teens with deep bites. Let’s take a further look:

What about the Twin Block?

The Clark Twin Block is the traditional “gold standard” for jaw advancement/protrusive teeth correction in growing children/teens and has been used by Orthodontists for decades. It’s made of two removable appliances – one for the upper teeth and one for the lower – each with a block of acrylic built onto them. When the mouth closes, the blocks meet at an angle that again encourages the lower jaw to posture forward as shown:

Pros:

• Effective: Very good at posturing the jaw and encouraging growth
• Cost: Often less expensive than Invisalign® MA

Cons:

• Bulky: Can affect speech, especially at the start of treatment
• Confidence: Can make the wearer more self-conscious
• Less discreet: More noticeable than Invisalign® MA
• Less efficient: Usually corrects the jaw first after which fixed braces are needed to straighten the teeth leading to longer overall treatment
• Breakage: Increased risk of metal wire breakage

Things to Consider

For successful treatment with either appliance, these are the factors to consider:

• Compliance: Strict discipline is needed as they must be worn 20-22 hours a day to be effective
• Cost: Invisalign® MA is often more expensive than a Twin Block
• Suitability: Growing child/teen patients with ‘favourable’ jaw growthpotential. Not suitable for every case
• Risk of loss: Both appliances are removable and so can be lost/misplaced

Conclusions

1. Both appliances are effective with their aims of encouraging lower jaw growth and the correction of protrusive front teeth to create a healthy bite and improved facial balance.
2. The Twin Block is the traditional, ‘tried-and-tested’ functional appliance but it has limitations. Invisalign®’s newest innovation, MA uses ‘precision wings’ or ‘occlusal blocks’ to perform the same functions but does so more discreetly and efficiently allowing simultaneous bite correction and tooth straightening.

Your Specialist Orthodontist will help you choose the option that’s best for your child/teen’s needs, growth stage, and lifestyle!