MOPs speeds up tooth movement according to this new trial!
We all would like to speed up the rate of tooth movement. This new trial shows that Micro osteo-perforation (MOP) speeds up tooth movement.
Recently, investigators have carried out several trials to evaluate methods of attempting to speed up tooth movement. One of these methods is micro-osteoperforation or MOPs. In this technique, small holes are made in the alveolar bone. This then results in regionally accelerated phenomenon or RAP. I have posted about trials that have looked at this before. I pointed out that there is limited evidence of a clinically significant effect on the rate of tooth movement. This is an interesting and clinically relevant area of orthodontic research. I was, therefore, very interested to see this new trial.
A team from India did this study. The Journal of Orthodontics published it.
Sonal Attri et al
Journal of Orthodontics: https://doi.org/10.1080/14653125.2018.1528746
They set out to ask this question;
“Does MOPs influence the rate of tooth movement and pain when used for en masse retraction”?
What did they do?
They did a 2 arm parallel allocation randomised clinical trial with an allocation ratio of 1:1. They registered the trial.
The PICO was:
Participants:Orthodontic patients aged 13-20 years with an irregularity index of <3mm. They had extraction of mandibular and maxillary first premolars and needed en masse retraction for space closure.
Intervention:MOP using the Propel device. They did this at the start of space closure and then every 28 days until the extraction spaces were closed.
Control:Space closure without MOP.
Outcome:Rate of space closure in mm/month. They measured this on digital models. They recorded pain perception with a visual analogue scale 24 hours after MOP, 7 days and 28 days after MOP.
I thought that other important areas of their methodology were:
They closed space on a 19×25 ss wire using a standardised force of 150g on each side of the arch.
They started the retraction immediately following the MOP.
Anchorage preparation was done by banding the second molars and fitting a palatal arch.
They measured the space closure by drawing a mid palatal line on the software. They then drew perpendicular lines towards the distal surface of the canine to the mesial surface of the second premolar. This was the amount of space closure.
They did a clear sample size calculation, data collection was blinded, randomisation and concealment was good.
What did they find?
60 participants entered and completed the study. There were no differences between the treatment groups at the start of treatment.
I have extracted the relevant data on rate of space closure in mm/28 days, into this table.
|Space||MOP||No MOP||Difference (95% CI)|
|Upper right||0.89 (0.17)||0.63 (0.11)||0.25 (0.18-0.33)|
|Upper left||0.88 (0.21)||0.53 (0.19)||0.35 (0.25-0.45)|
|Lower right||0.8 (0.19)||0.53 (0.1)||0.27 (0.19-0.35)|
|Lower left||0.73 (0.1)||0.49 (0.1)||0.24 (0.17-0.31)|
All these differences were statistically significant. They did not detect any difference in pain perception.
Their overall conclusion was:
“There is a definite enhancement of orthodontic tooth movement when MOP is done before starting tooth movement”.
What did I think?
I thought that this was a well-done small study. I also thought that their results were interesting. However, we need to consider whether the effect size was clinically significant. This is for you to decide.
I thought that a good way to approach their data was to look at the effect that these differences may have on the overall time for space closure. For example, if we look at the greatest difference, which is space closure on the upper right first premolar space. They reported that the average pre-treatment space in the maxilla was 5.0mm. If we take an average space closure of 0.89mm/month for the MOP and 0.63 mm/month for no MOP. Then the average time to space closure would be 5.6 months for the MOP and 7.9 for the no MOP group. I feel that these differences are clinically significant.
However, I have a word of caution. We need to remember that they only looked a space closure. I am not sure that we can extrapolate this finding to suggest that we can reduce courses of treatment by 2 months. As a result, while the results are interesting, we still need to see a study that has evaluated the effects of MOPs over the whole course of orthodontic treatment. This, of course, will involve a substantial increase in the burden of care and we would be looking for a substantial difference to justify this?
Several investigators have now done studies on MOP and I am going to do a post in the next weeks to try to summarise the overall evidence for this technique.
Emeritus Professor of Orthodontics, University of Manchester, UK.