August 30, 2021

A new trial looks at the Carriere appliance combined with miniscrews!

Following the complete absence of research into the Carriere appliance, it is good to see that investigators are doing trials into this appliance. This new trial looks at the effect of reinforcing lower anchorage with miniscrews. The results give further insight into the mode of action of this appliance.

As we all know, the inventor and other KOLs have extensively promoted this appliance with little evidence for their claims. I have posted in detail about this before.  Several investigators have shown that this appliance is a new way of applying Class II elastics.

This latest trial looked at the overall effects of the appliance concerning anchorage loss in the lower arch.


What did they ask?

They wanted to:

“Evaluate anchorage control using miniscrews vs an Essix appliance in the treatment of Class II malocclusion using the Carriere Motion Appliance”.

What did they do?

They did a parallel-group 1:1 allocation randomised controlled trial.  It was good to see that the team registered their trial before they carried it out.  They enrolled the participants in their trial from April 2014 to August 2015.  The PICO was

Participants: Post pubertal female orthodontic patients with Class II Division 1 malocclusion in the full permanent dentition.

Intervention: Carriere Motion appliance with miniscrew anchorage in the lower arch.

Comparison: Carriere Motion appliance with ESSIX appliance anchorage in the lower arch.

Outcomes: Amount of anchorage loss in the lower arch. They mostly used cephalometric measures to evaluate this outcome. Secondary outcomes were the amount and type of molar movement and treatment duration.

They used pre-prepared randomisation and concealed the allocation using a variation of sealed envelopes.  Data analysis and collection was blind.  Importantly, they did a sample size calculation based on a previous study looking at anchorage loss.

They collected the data at the start and end of CMA treatment from CBCT images.

What did they find?

The investigators randomised 24 participants to the miniscrew (12) or ESSIX(12) groups.  There were no differences between the groups at the start of treatment.

They included a large amount of data in the paper derived from the CBCT images.  I am not going to repeat all this here. However, as this paper is open access, you can easily have a look at it all.

I thought that this was the most relevant information.

  • The mean time to correct the Class II molar to Class I was 6.1 months (SD=3) for the miniscrew and 7.5 months (SD=3.7) for the ESSIX groups.  This effect was not statistically or significantly different.
  • In the miniscrew group there the lower incisors proclined by 0.86 degrees, and in the ESSIX group, they proclined by 5.3 degrees. This difference was statistically significant. When I looked at the confidence intervals of the difference, this was from -7.28 to -1.5. I thought that this was relatively wide and is a reflection of the low numbers in the study.
  • The mandibular molar moved forwards by 1.1 mm in the miniscrew and 2.1mm in the ESSIX group.
  • I looked closely at their detailed ceph tables and found that the mean ANB change for the miniscrew group was 0.04 degrees, and for the ESSIX group, this was 0.24 degrees.  These differences were not statistically or clinically significant.

The investigators concluded.

“The use of miniscrews resulted in a decrease in the amount of anchorage loss in the mandible”.

What did I think?

This study does add to the increasing evidence on the Carriere appliance. It is a nice small study. However, we need to remember that it is small. As a result, there must be a degree of uncertainty in the data. Importantly, this is reflected in the wide 95% confidence intervals.

When I looked at the detailed tables, I thought that they clearly showed that the appliance influenced the position of the teeth and not the skeletal bases.  This finding is similar to other investigations. There was no evidence of the CMA” bringing mandibles forward”. I wonder if it is time that the inventor and KOLs stopped making this claim?

I think that it was relevant to consider that there was less anchorage loss with miniscrews.  While this difference is in the region of a few degrees, we need to bear this in mind when we develop our treatment plans.

It also appears that the mean treatment time is about six months. Again, this contradicts the claims made by the paid proponents of this appliance.

Final thoughts

I cannot help thinking that the CMA is a complicated way of applying Class II elastics. Unfortunately, adding miniscrews seems to make it even more complex.  In orthodontics, keeping it simple works very nicely, but this does not make extra money?

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Have your say!

  1. Thanks Kevin for your evaluation, I’ve been curious about this appliance as many colleagues like it but I’ve not tried it yet, and I’m now even more inclined to stick with what I currently use!
    Might I ask is there a small but important decimal point missing in the results? i.e. was it 7.5 months for the ESSIX group? I assume so given the difference was not statistically different.
    The mean time to correct the Class II molar to Class I was 6.1 months (SD=3) for the miniscrew and 75 months (SD=3.7) for the ESSIX groups. This effect was not statistically or significantly different.

  2. Thanks for sharing this article and will go take a closer look at it. Under your first point of relevant information:

    The mean time to correct the Class II molar to Class I was 6.1 months (SD=3) for the miniscrew and 75 months (SD=3.7) for the ESSIX groups.  

    I’m assuming you meant 7.5 months and not 75 months?

  3. Every overlay I have seen demonstrate some Cl II correction with the CMA was overwhelmingly due to the mandible coming forward. Seems like an alternate World. But I am sure glad significant distalization claims are going away.

    • Maybe ‘mandible coming forward’ is a result of removing impediment (Class II intercuspation locking) for the mandible to grow normally(into class I). This disocclusion may be the most important attribute of most of the functional appliances. This is probably glorified as ‘growing the mandible’ by proponents and KOLs, and countered by our ‘evidence-based ‘ friends?

  4. I think we should all be sophisticated enough at this point to realize that KOLs are merely marketing salesmen. So beyond the hype behind the Carriere appliance, we have used it successfully and extensively for several years. Yes, I fully realize it doesn’t grow mandibles (does any appliance)? We use it because its simple to place, easy to monitor progress, used at the very beginning of treatment when cooperation is at its peak and the opportunity to move to alternate therapies is most convenient. By the way it’s not a whole different from the bioprogressive concept of class II elastics to an upper sectional wire with a utility arch for anchorage.

  5. I really think that we need a better idea of what we can and, more importantly, cannot do. There seems to be a view amongst some that anyone can be forced into a perfect class 1 by the application of more braces and for longer and that failure to do so, rather than being due to biology, is due to failure of will of either the patient or the operator. I would advocate something more pragmatic but that would involve leaving some people without treatment (the horror, the horror) or with partial treatment (to just treat the main problem) hence admitting that perfection is neither achievable or desirable.

  6. Thank you for your post and general efforts .
    -In response ,I ,respectfully request that your last statement”does not make extra money”is ,again with respect,unecessarily discourteous.
    -I very much appreciate your efforts in guiding our profession,at least at the specialist level,to an evidence – based approach.
    Kindly,please bear in mind that those of us in private,fee for service ,practice have the ultimate evidence base.That is : the fact that referral dentists ,patients,parents expect (and so they should,)results for payments provided.Inability to provide good results in a reasonable amount of time ,axiomatically in this situation ,leads to practice failure.
    No amount of literature knowledge and interpretation will change this !
    -Your efforts to “reign in “the KOL,as they “overstep the mark “are admirable .The self appointed epithet ,KOL,has become meaningless as they mutually laud each other with abandon.The term is meaningless to the point of embarrassment . I see little in the way of a response to your ,and many others criticisms.They also have shown little allegiance to products and companies as they change allegiance with the prevailing wind.
    Finally,I note that some clinicians ie.the more academically based,especially related to a socialised dental care system ,find the discussion of finances and money ,distasteful.I do not.As highly trained and educated clinicians ,deserve to be well remunerated,as long as we work hard,efficiently and conscientiously .The 18 staff and 10 related offspring in my offices certainly deserve adequate payment for their efforts in a fee for service practice.

  7. Good job!
    We know that the Carriere is an expensive way to apply class II elastics and therefore it does not make the jaw grow, but on the other hand … are there any devices that do it? Don’t we always have dentoalveolar effects?
    What I found useful in the Carriere is the timing of application of the Class II elastics, as I find that the patient collaborates much better at the beginning of the therapy rather than at the end .. this is the real advantage of the device!

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