Does remote monitoring of invisalign treatment work ?

Post by 
Kevin O’Brien

his post is about a study that looked at remote monitoring of aligner treatment.  This is a fascinating paper.

Teleorthodontics using remote monitoring of treatment progress is becoming popular.  Like many new(ish) techniques, there are many claims for its effects.  The most compelling is the potential to reduce the number of patient attendances.  This may be useful in optimising patient and clinician time. Furthermore, it may have a role to play in the provision of care in remote areas, where travel may be challenging.  

This form of treatment may be particularly relevant to treatment with aligners.  Dental Monitoring is software that enables patients to take images of their teeth with a smartphone. Their aligner treatment can then be tracked, and instructions on aligner changes can be given.  

A team from Dubai looked at the effectiveness of this technique in this new study.  Progress in Orthodontics published the paper.

Clinical outcomes and patient perspectives of Dental Monitoring® GoLive® with Invisalign®—a retrospective cohort study.

Ismaeel Hansa,  Steven J. Semaan  and Nikhilesh R. Vaid

Prog Orthod. 21, 16 (2020).

What did they ask?

They did the study to answer the following question on remote monitoring;

“What are the effects of Dental Monitoring on Invisalign treatment”?

What did they do?

They did a retrospective study on a sample of patients who had completed their treatment. The PICO was:

Participants: Consecutively treated patients who had aligner treatment.

Intervention: Remote dental Monitoring.

Comparison: No dental monitoring, treatment as usual

Outcomes: The primary outcome was treatment duration and the number of attendances. Secondary outcomes were the total number of aligners, time to initial refinement and patient perspective of dental Monitoring.

They did a sample size calculation based on detecting a difference of 3.52 attendances between the groups. This suggested a sample size of 27 patients in each group. However, they decided to enrol 215 patients. This increased the power of the study.  I will return to this later.

The patients were aged between 30 and 65 years old. An experienced orthodontist did their non-extraction treatment.  They recorded the outcome measured from the patient’s record.  Finally, they recorded the patient’s perceptions of their treatment using a questionnaire.

What did they find?

At the start of the study, they did not detect any difference between the two groups.  At the end of the treatment, the only statistically significant difference they discovered was with the number of appointments. I have put the relevant data into the table below.  The mean treatment duration was 14.8 months for the DM group and 13.9 months for the control. There were no differences in number of refinements and time to the first refinement.

OutcomeDental Monitoring
(mean and 95% CI) Control
(mean and 95% CI) Difference
(mean and 95% CI)
Number of appointments7.57 (6.9-8.1)9.8 (8.9-10.6)2.26 (1.3-3.2)

When they looked at the patient questionnaires, they found useful information. In summary, most of the respondents found that the images were easy to take, and 72% were satisfied with the level of communication with the orthodontist.  The mean time to take a photograph was 5 minutes. Finally, 78% were satisfied or very satisfied with Dental Monitoring.

What did I think?

I thought that this was a really interesting study of new technology. I do not often review retrospective studies. However, I decided to look at this study because of its novelty and future application to clinical practice.  My general feeling is that this study provides us with useful information for future research.

I am not so confident that the results should change clinical practice.  I hope that I have good reasons for this. Firstly, the study is retrospective. As a result, it must suffer from selection bias. Importantly, we do not know the direction of the bias.

I also had questions about the sample size. From the sample size calculation, the investigators felt that they needed to collect data from 27 patients in each group to detect a clinically significant difference of 3.52 visits.  This was their definition of clinical significance. However, they decided to collect information from a much larger sample.  This means that they are at risk of “overpowering” the study. One consequence of this is that a smaller effect size may be statistically significant.  This is what happened with this study with the difference of 2.26 visit that they found.

Furthermore, the 95% Confidence Interval of this difference is from 1.3-3.1.  This means that if the study is repeated, the actual value may be as low as 1.3 visits or as high as 3.1 visits. This adds uncertainty to the data.  You now need to decide whether this is clinically significant in your practice.  I am not sure that this is.

Final comments

I am not sure that this study provides us with definitive information about the value of dental Monitoring. However, it may shed some light on the possible effects of this delivery of care.  Importantly, it does give us information that can be used to power new trials into Dental Monitoring.