The ALF (Advanced Lightwire Functional) appliance is a type of orthodontic appliance often used by general dentists (not orthodontists) providing orthodontic services. There is a plethora of misinformation and unsubstantiated claims surrounding the appliance so the purpose of this article is to give some insight into what it does and why it is not used by orthodontic specialists.
The ALF appliance was developed in the 1980s by a general dentist. It consists of a series of custom-made wires that are bonded to and exert pressure on the teeth. It is marketed as being “more comfortable” and “less restrictive” than braces, allowing patients to eat, speak, and even play sports without any major disruptions to their daily activities. It appears that the appliance was developed as an alternative to traditional palatal expanders which are viewed as requiring “brute force” rather than the apparent less invasive approach from the ALF appliance.
There are numerous unsubstantiated, and quite frankly, ridiculous, claims associated with the appliance. For example – it is said that the ALF appliance encourages the bones and teeth to move to their correct positions and that it helps the body “naturally remodel” and realign the teeth and jaws. Further, it bio-modulates the autonomic nervous system, making this a highly effective therapy and “go-to” treatment for patients and specifically, children with sensory and nervous system dysfunction such as Autism Spectrum Disorder (ASD) and ADHD.
These claims have not been verified by any research study and neglect widely accepted basic principles of biology and orthodontics. There is nothing advanced about the appliance as it is merely a dental tipping appliance. It is basically a glorified quad helix appliance, which is also considered in orthodontics to be a dental tipping appliance.
Let’s review dental tipping/expansion vs. skeletal expansion to help explain what the ALF appliance actually does. When an active orthodontic appliance is put on the upper teeth with an associated expansion force (i.e. one that is pushing the teeth outwards) it can result in either: 1) dental expansion (the teeth moving outwards from the bone), 2) skeletal expansion (the two maxillary bones moving outwards making the upper jaw wider), or 3) a combination of dental and skeletal expansion. The variables that dictate what happens are: 1) age of the patient, 2) interdigitation of the maxillary midpalatal suture, and 3) force exerted by the appliance.
With increasing age, the maxillary midpalatal suture becomes more interdigitated. To get skeletal expansion, we aim to “break” the interdigitation to move the two maxillary bones apart. Because the orthodontic appliance is bonded to the teeth, we will always get some element of dental expansion but we want to maximize the skeletal expansion.
Light forces being applied to an interdigitated suture do NOT result in much, if any skeletal expansion. That being said, light forces applied to a suture in a 7 year old can result in some skeletal expansion but involve mostly dental expansion. A jackscrew (i.e. the main component of a traditional palatal expander), which applies a stronger yet intermittent force (of 0.25 mm of expansion) is viewed to be way more effective in opening a suture. That being said, a jackscrew used in a 13 or a 14 year old may also result in significant dental tipping due to the age of the patient and the associated increasing interdigitation of the maxillary suture.
Because the ALF appliance does not contain a jackscrew it delivers light forces on the teeth that are not powerful enough to result in skeletal expansion in most situations. It merely tips the teeth outward resulting in dental expansion. While the “results” may appear to be effective (and comparable to a traditional palatal expander) since the upper teeth are in a more outward position than they were before, it is most likely not due to any skeletal expansion.
It is unfortunate that this appliance is being recommended to young kids who need skeletal expansion and lose out on the window to actually get it. Doing excessive dental expansion with an ALF appliance moves the teeth outward, possibly out of bone, and predisposes children to future gum recession as adults.
In summary – if your child is being recommended an ALF appliance, please be skeptical and reconsider. Go for a second opinion with an orthodontist who is a specialist in moving teeth and jaws to get a better understanding of what your child needs.