July 27, 2020

Does remote monitoring of Invisalign treatment work?

This is becoming a “clear aligner month” for research papers.  This 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). https://doi.org/10.1186/s40510-020-00316-6

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)
(mean and 95% CI)
(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 trials into Dental Monitoring.

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Have your say!

  1. This concept still carries some concerns for me. It is all well and good to justify this on the basis of patients being remote areas and therefore being unable to attend regularly. However, my issue revolves around this kind of practice becoming the norm for conventional treatment and resulting in sub standard results as a consequence. If that is the case then the specialty will have shot itself in the foot in the long term. I believe that will have far-reaching consequences from numerous perspectives. I fear many of the protagonists of this are promoting it for less than noble reasons and will allow it to become more commonplace with the level of orthodontic treatment results suffering in the long run. It is a dangerous and slippery slope in some ways.

    • The practice of orthodontics has evolved in the past and will continue to evolve in the future; how remains to be seen.

      I feel that remote monitoring will be successful if it’s able to reduce patient’s office visits while increasing regular monitoring, and without compromising results.

      Nevertheless, studies do need to be performed on new technologies in order to test the veracity of their claims and to determine their effect on the practicing orthodontist.

  2. Interesting study.
    In my view ,it does not matter how you do the monitoring as long it is done well!
    Telemonitoring worked OK during covid crisis.
    Generally ,I am working on weekly trays and give 10 to 14 .
    Covid taught us a lot but I would still suggest ,in person monitoring at 3 month interval is not placing undue time constraints on the pt.
    PLEASE,no more discussions whether invisalign “works”. That horse has left the barn.

  3. Thank You for as always a short and analytical summary of the study! I am all for any trick supporting and increasing patient compliance which is a true root of any monitoring whether it is in-office visits or remote apps. My belief is that the patient will be more appreciative of doctors’ personal attention and those who don’t will have to learn hard way through SDC. For the same reason, I’m very cautious supporting remote interaction with the patients as I think passing Doctor Branding for the brand of the App the patient is using resolves the importance of the doctor and destructive to the whole concept of building the practice with dedicated patients which is a core acquisition value. However, just to demonstrate that I’m not an old dinosaur standing my ground, I do use a service where the patients send me 5 photographs and based on it software generates 3D treatment animation that I use for new patient engagement remotely prior to bringing them into the appointment for actual impressions/ scans. Saves me time for “selling “the case and all financial arrangements are done by the time of the first visit.

    • Thx Kevin!
      This is a timely blog topic as in many countries we face practice lockdowns that reduce the ability to conduct face to face care, and thus possibly effect quality of treatment and treatment outcomes. I enjoyed reading the paper, and was very happy to see that although majority of patients in this study desired reduced appointment frequency, there were still 12% who preferred face to face doctor time :). My major question is whether decreased appointment frequency does effect – positively or negatively – treatment outcome? I could not see any post treatment occlusal outcome measures , just the pre-treatment Little’s to match the sample severity. Wonder if it was performed? I would think that this was a critical piece of information? The study concluded that use of Dental Monitoring (DM) in a sample of mild to moderate patients using the Invisalign system largely enjoyed the DM experience (for the product they used), and reduced their appointment frequency saving precious time. This is favorable, I believe, only if the clinical outcome is equivalent or better than the control. The placebo factor associated with DM alone may contribute to improved compliance and possibly improved outcome? Would be helpful to know!
      My other questions would revolve around the benefits of remote monitoring in terms of oral hygiene maintenance for both fixed and aligner patients. Theoretically such monitoring could benefit outcomes in more ways than reduced appointment frequency, as eluded to by the authors. Saving time and money are strong motivators for the adoption of such a technology, but I would rate improved occlusal outcome and reduced iatrogenic disease potential as more important. I was not sure from the paper whether the clinicans used the product to monitor only aligner adaption, or also compliance with elastics, attachment integrity and oral hygiene maintenance, and did they ever over-ride the information provided by DM? Wish I could travel to Dubai or to Paris to find out…

      • Hi, thanks for your interest in our paper

        1) Treatment outcome was not assessed in this study, but I agree with you that this is an important piece of information that is missing. We have done another study that should be available in AJODO early next year that additionally tests the accuracy of achieving the predicted tooth position between the two groups.

        2) DM does assess for OH, attachments etc. If the ‘full’ version is used (not used in this study) it also tracks individual tooth movement, OJ and OB. We did not measure the times that DM was over-rided.

  4. i was not aware one could “överpower” the study !

  5. So I’ve done my own calculations.
    It takes a staff member the time of at least two patient check visits to teach how to scan in dental monitoring. So the ” cost of implementing ” is two visits. If the size of the effect is 1.6 to 2.1 visits, and you need to pay dental monitoring money (you do) and even though the patient is not visiting, you need a staff member to view and act of the the incoming DM reports this study result confirms my bias, that the ROI is even or nil.

    • I agree that DM is not appropriate for all practices, depending where in the world they are located, type of practice, and the patient demographics.

      This study simply aimed at investigating the clinical outcomes of DM. The cost of DM (which is a monthly fee and varies with the DM option chosen), in addition to the doctor and staff time, should be compared to the financial and clinical costs associated with extra physical appointments. The extent of benefit (or lack thereof) will be based on the individual office’s costs, scheduling and protocols.

  6. Thank you for your time and effort in reviewing our paper, I have been an avid reader of your blog over the last 2 years or so.

    Regarding the power of the study: Our primary objectives were both treatment duration and no. of appointments. Some proponents of DM claim a reduced treatment time due to proactive monitoring, hence we decided to enroll as many patients as possible to obtain adequate power in determining true differences for treatment duration.

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