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.
A team from Cairo did this study. The Angle orthodontist published the paper (open access).
Ahmed S. Fouda et al. Angle Orthodontist: DOI: 10.2319/021421-126.1
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.
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?
Emeritus Professor of Orthodontics, University of Manchester, UK.