What are the complications of Class II malocclusion treatment?
There are many ways to treat Class II malocclusion in adolescents. They all seem to have similar effects. But do some have more and different complications? This intriguing new systematic review provides us with great information for our patients.
Class II malocclusion may be treated in many ways. Investigators have done a large number of trials into the effect of functional appliances. When we evaluate this work, we can divide these into removable or fixed appliances. Interestingly, when investigators have used traditional orthodontic outcomes, for example, cephalometrics or measures of occlusion, there are minimal differences between interventions. However, there is an increasing amount of information on other effects that are particularly relevant to our patients. These include discontinuation rates, pain and perceptions of treatment. These investigators did this review to evaluate these results.
A team from the London Hospital, in the East End of London did this review. The AJO-DDO published the paper.
Moaiyad Moussa Pacha, Padhraig S. Fleming, and Ama Johal
AJO-DDO. Online advanced access. https://doi.org/10.1016/j.ajodo.2020.03.021
What did they ask?
They wanted to find information on:
“The compliance and patient experiences during the wear of Class II correctors.”
What did they do?
They did an excellent systematic review of the literature. They followed the standard steps of electronic and hand searching, identification of the papers, assessment of Risk of Bias and extraction of data.
The PICOS for the review was:
Participants: Orthodontic patients less than 18 years old with Class II malocclusion.
Intervention: Treatment with a Class II appliance
Comparison: A comparison or control group was not essential
Outcomes: Prevalence of emergencies and complications. Patient experiences and oral health quality of life.
Study design: RCTs, CCTs, observational cohort and prospective case series (>10 patients).
They evaluated bias with the Cochrane Risk of Bias tool for the RCTs and the Newcastle-Ottowa Scale for the other studies.
Importantly, they decided to carry out a meta-analysis that only included studies with low or unclear risk of bias.
What did they find?
They found a total of 27 unique datasets. Of these, 9 were RCTs, 6 were controlled clinical trials, 1 was a prospective case series, 8 were prospective observational studies, and 3 were qualitative studies. Interestingly, they pointed out that nearly all the studies were done in a hospital or dental school setting. They identified data from 1676 participants, and most were treated with some form of functional appliance. They divided these into 682 removable functional appliance patients and 682 fixed functionals. The remaining patients were treated with headgear (186) and the Carriere (42) appliances.
When they looked at the risk of bias for the randomised trials. They found that only 1 study was low risk, 2 were unclear, and 6 were high risk. For the non-randomised studies, they felt that 6 were low and 9 were moderate quality.
They decided that 12 of the studies could be used in the meta-analysis. This included 3 RCTs, 1 cohort, 3 CCTs, I cross-sectional and 1 case-control study. They selected these based on their quality in terms of risk of bias.
They provided a large amount of data. I am only going to mention what I felt were the most clinically relevant findings.
- They found that complications were high in fixed and hybrid functional appliances (69%) when compared to removable functionals (34%).
- The mean number of emergencies for removable appliances was 0.8 (95% CI= 1.1-1.2) and 2 (95% CI=0.9-2.0) for fixed functionals. However, heterogeneity was high at 88% for removable and 94% for fixed.
- Treatment discontinuation was higher for removable appliances at 35% (95% CI= 28%-42%) compared with fixed designs at only 1% (95% CI= 1%-10%). Again, the heterogeneity was moderate being between 34% and 66%.
- In general, the qualitative studies reported a significant negative impact with removable functional appliances.
What did I think?
I thought that this was an ambitious and complex systematic review. Importantly, they looked at the effects of treatment from a patient’s point of view. This approach is refreshing because these findings are more useful than the endless analyses of cephalometrics and occlusal index scores. As a result, this study adds to our knowledge.
When I looked at the findings, I thought that they were clinically valid. In many ways, it not surprising that the failure rate of removable appliances appears to be associated with negative impacts on quality of life. It is also a common clinical experience that there are more complications with fixed functional appliances. However, I did not appreciate the marked difference in failures until now.
I also felt that it was good to see a team of reviewers identify several studies and then exclude a fair number, because of a high risk of bias or low quality. This is markedly different from the current trend in orthodontic systematic reviews to include everything that they find in a meta-analysis regardless of quality. Importantly, they also highlighted the heterogeneity in their results and explained how this influences the uncertainty in the data.
I suggest that as many people as possible read this paper. It is an addition to the literature and is relevant to all practitioners and trainees.
Finally, this study provides us with useful clinical information on the various risks and benefits of the types of Class II appliances. We can use this as part of our consent process.
Emeritus Professor of Orthodontics, University of Manchester, UK.