March 20, 2023

Clear aligner use in the mixed dentition: Who does what?

This new paper provides information on using clear aligners for mixed dentition interceptive treatment. This area is controversial, and the results give an interesting insight into this treatment.

The whole subject of interceptive mixed dentition treatment is controversial. While orthodontists often carry out this treatment, we do not know much about its effectiveness. As a result, we know even less about using clear aligners for this treatment.   While research is lacking, looking at this new paper that reported a survey of clear aligner use for mixed dentition treatment was helpful. This is an excellent first step because It provides case report-level information and may be considered the first research phase.

A team from Virginia, USA did this research. The AJO-DDO published the paper

Clear aligner therapy in the mixed dentition: Indications and practitioner perspectives.

Nicholas M. Lynch et al.

AJO-DDO online:

Their literature review indicated that mixed dentition clear aligner treatment is becoming more popular. Furthermore, the companies and their paid clinical salespeople claim that aligners have advantages over fixed appliances for interceptive treatment. These are fewer appointments, fewer emergency visits, less chair time, and reduced treatment time. If this is the case, they are an orthodontic panacea for treating this age group. This would be reflected in the widespread use of aligners.

What did they ask?

They asked:

  • How often do orthodontists provide clear aligners in the mixed dentition treatment (CAMD)?
  • What are the indications for doing CAMD?
  • What do orthodontists feel about their patient’s compliance and oral hygiene with CAMD?
What did they do?

They did a cross-sectional survey of orthodontists using a 23-question survey. This was sent to a randomised nationally representative sample of orthodontists (n=800)  and a specific sample of high-aligner volume orthodontists (n=200.  They identified these practitioners from the AAO online data or Align Technologies Invisalign provider website.

They sent out the first survey and followed up with a repeat mailing after six weeks. 

What did they find?

One hundred and eighty-one orthodontists returned their survey. Resulting in a response rate of 18.1% (I will return to this later).

I thought that these were relevant and interesting findings:

  • Most of the respondents were solo private practitioners (76%).
  • They treated 31% of their patients with clear aligners and 69% with fixed appliances.
  • In addition, 21% of their patients had phase I or early treatment in the mixed dentition.
  • When they looked at this mixed dentition treatment, the orthodontists used clear aligners for 13% of the patients, and 85% were treated with fixed appliances.
  • The respondents were more likely to use fixed appliances than CAMD for all clinical conditions except spacing and diastemas.
  • Sagittal correction was among the least commonly selected reasons for CAMD.
  • There were no differences between the treatments for compliance or treatment duration. However, they felt that oral hygiene was better with CAMD.
  • There was a general tendency to increase CAMD over the next five years.

The study team concluded:

“CAMD use is less than FA for mixed dentition treatment, but this will likely grow.

Most respondents thought CAMD was less useful than FA for growth modification, skeletal expansion and habit cessation.”

What did I think?

This paper is another helpful first step in understanding mixed dentition aligner therapy. This is because this data is derived from practitioners’ experience. Significantly, it condenses their clinical experiences, a significant component of evidence-based care.

The results indicate that orthodontists do not use CAMD for all forms of interceptive treatment. Instead, orthodontists use them for simple problems. This reflects the general feeling about using clear aligners (although some may disagree). Importantly, this study points to treatment that could be investigated in larger-scale clinical studies into interceptive treatment.

When I considered the good points of this study, the sample selection method was suitable, the questions were relevant, the data analysis was appropriate, and the paper was well written. My only concern was the response rate. While some may feel this was low, it is similar to or higher than other survey studies. Nevertheless, I wanted some information on the non-responders, which would indicate possible response bias.

Final comments

This was a useful piece of research that provided good basic information on clear aligner use in the mixed dentition. Importantly, it gave us more information than the type of presentation done by KOLs on the clear aligner circuit who feel that interceptive treatment “cannot be done with fixed braces”.

Related Posts

Have your say!

  1. Dr Proffit doit se retourner dans sa tombe. CAMD est une autre manière de rendre 2 phases de traitement pour corriger des classe II.
    Dr. Proffit must be rolling in his grave. CAMD is another way to render 2 processing phases to correct class II.

    • Dr. O’Brien,

      Thank you for bringing this paper to my attention. I worked with Align in the developmental stages of aligners systems for mixed dentition. I backed out when I started to realize Align wanted to use aligners for all situations and not just problems where a clear aligner approach may be beneficial. As a dual trained individual, I have done mixed dentition treatment and feel it is valuable to patients. A goal-oriented approach to treatment will suggest fixed appliances are better for the patient in some cases and clear aligners may be better in other cases. A thinking cap is a very good thing.

      Dr. Chamberland, as one of Dr. Profitt’s students, I would like to dispel a common misperception. Dr. Proffit was not against 2 phase treatment, nor did he push for only one phase. He only said that the outcomes were similar so there needed to be a compelling reason to do Phase I in a Class II case. And this thought process did not apply to the vertical or transverse dimensions. Treat those problems, including in the mixed dentition, when it was appropriate.


    • I disagree. 🙂

      I have, for the last 2 years treated class II patients with Invisalign First MA (mandibular advancement) as functional appliance, in which the alignment came for “free” in the aligners.

      Hopefully one day a true RCT will be done abut this.

      PS. I am not payed by any aligner company

  2. Phase I overtreatment, in many counties is a well-known fact, saying: if I will not treat that child somebody else will treat him (Phase I and II as well). Placing the pieces of plastic in the mouth of the children reminds me of the apple one of the ancestors (Andreasen?) gave his son to hold for 3 months in his mouth (summer vacation) and surprisingly the lower jaw grew. We know that there is not even one RCT study that ever proved that we can grow jaws. Since clear aligners treatment, especially Invisalign became a brand name, the need to get the treatment is more likely of a show than a need. The orthodontist does not have to make any effort in persuading the small children (patients) or the big children (parents) about the need for the treatment since it demonstrates to everybody in the neighborhood without doubt: yes we can! Nobody needs an RCT to study it since ‘they’ say it works, so it works. Do not fall into the trap. Since 2003 the average change the clear plastic can perform is around 50%. So what do we sell, give, and treat, our patients to? Just imagine this percentage in root canal treatments? However, it looks like traditional orthodontics is over. Happy to retire!!!

    • ”Average change the clear plastic can perform is around 50%.” Good old claim we hear all the time.
      Let’s say you get 50 % after 6 months (26 aligners).Then let’s say you do it twice or 3x. 12-18 months treatment. You may get a result right?
      It may be traditional orthodontics but with different mechanic.

    • Loved your letter in the AJO-DO: “…the specialty is consciously giving up excellent results in favor of acceptable results as its therapeutic goal.”

  3. Having worked in solo practice AND corporate AND group practice situations, I just offer that solo practitioners would be much more likely to respond to this kind of questionnaire.

Leave a Reply

Your email address will not be published. Required fields are marked *