Piezocision massively increases the speed of tooth movement!
There is currently a lot of work being done to discover methods of making teeth move faster. This new study shows some remarkable results for piezocision.
Over the past few years, researchers have published several studies looking at the effectiveness of methods to increase the speed of tooth movement.
Most of these studies have concluded that there is limited or no effect of these new interventions and that “nothing works”. Until this new trial, which reveals remarkable results.
Piezocision-assisted orthodontic treatment using CAD/CAM customised orthodontic appliances: a randomised controlled trial in adults
Carole Charavet et al. EJO: Online advanced access. doi:10.1093/ejo/cjy082
What did they ask?
They wanted to investigate whether using piezocision with CAD/CAM customised appliances influenced treatment time of patients with mild crowding.
Piezocision is a relatively invasive method of carrying out flapless corticotomies. Here is a nice video.
When I look at this, I am not sure that this is ‘minimally invasive”.
What did they do?
They did an RCT with a 1:1 allocation. The PICO was:
Participants: 24 adult patients with mild to moderate overcrowding requiring treatment with fixed appliances.
Intervention: They did piezocision two weeks after they placed the appliances.
Control: Treatment as usual, with no piezocision.
Outcome: Overall treatment time.
They fitted all the participants with CAD/CAM-produced self-ligating appliances. They used the following archwire sequence for all the patients; 014, 018, 014X025 and 018×025 Copper NiTi wires and 019×025 ss for finishing. The patients were seen every two weeks. They changed the archwires only when they could achieve full bracket engagement.
Finally, an independent orthodontist validated the appliance removal by reviewing study casts. They were not aware of the group allocation.
The sample size calculation was precise, and they based this on total treatment time. This showed that they needed 11 patients per group. Randomisation was clear, and the treatment allocation was concealed in envelopes. It was not clear whether they registered the participants into the trial before the assignment.
In addition, to treatment duration, they also collected data on the process of treatment and periodontal harms from direct examination and sequential CBCT images.
What did they find?
At the start of the study, there were no differences between the groups. All patients completed the study.
When they looked at treatment duration, the treatment duration in the piezocision group was 278 (SD= 80.2) days. Whereas, for the control group the duration of treatment was 393 (SD= 55.2) days.
This meant piezocision treatment was 1.6 times faster than conventional treatment with a 36% reduction in treatment time. This difference is clinically and statistically significant.
I thought that it was important that the time between archwire changes was significantly lower in the piezocision group for most of the archwires. These differences ranged from about 18 to 43 days.
There were limited or no differences in the other outcomes that they measured. However, the piezocision caused small scars in the gingivae.
In their discussion, they pointed out that there was variation in the findings of other studies. They suggested that this might be due to differences in the piezocision technique, the period between appliance adjustments and appliances.
What did I think?
I think that the results of this study are remarkable. I have previously posted about another study that showed similar results for the time to alignment. However, the results of this study are very clinically relevant because they evaluated the total treatment time. To make this difference clear; I have converted the difference in days to months. This was 3.8 months and is substantial. It is also amazing that one course of piezocision has resulted in such a significant reduction in treatment duration.
Because of this effect size, and I am a real cynic about these methods, I have carefully “taken this study to pieces”. I could not find any significant issues with the study. Most of my concerns are minor, and these are with the unclear method of registration of patients before allocation and the potential lack of power for the secondary outcomes.
However, I did spot that the time between archwire changes was shorter for the piezocision group. This may be a real effect, or as the operators were not blinded to the allocation, they may have been quickly moving up through the wires because they knew that piezocision had been used. This is a potential source of bias, and we need to consider this when we interpret the results.
While we may get excited about this study. We need to be a little cautious. Firstly, the sample size is small and may be subject to individual variation, as evidenced by the difference in standard deviations. We also need to consider whether the difference in treatment time is worth the traumatic procedure. Finally, we need to do more research and include the results of the studies into a meta-analysis. Nevertheless, the results of this paper are interesting and clinically relevant. Piezocision may have a clinical effect.
Emeritus Professor of Orthodontics, University of Manchester, UK.