Is Smile Direct Club teleorthodontic treatment effective?

Smile Direct Club is a company that provides remote teleorthodontic aligner treatment without the patient seeing a dentist. This is a controversial area of orthodontic treatment provision. I was, therefore, very interested in finding a paper on the effectiveness of this treatment.

Dr Marc Ackerman of Harvard Dental School did this study.  The Journal of Dental Research and Practice published the paper.

Before I go into details about this paper, I need to point out that this journal is classified as a “predatory” journal according to Beall’s list.  Wikipedia defines these as:

“Predatory publishing is exploitative and typically open-access, academic publishing business model that involves charging publications fees to authors without checking articles for quality and legitimacy and without providing the other editorial and publishing services associated with legitimate journals (open access or not). The idea that they are “predatory” is based on the view that academics are tricked into publishing with them, though some authors may be aware that the journal is poor quality or even fraudulent”.

In this respect, it is worth noting that this paper was submitted on May 2nd 2019, accepted on May 13 and published on May 16th.

So let us have a look at this paper.

The paper was written by Dr Ackerman, who is an Assistant Professor of Developmental Biology at Harvard Dental School and Executive Chair of the American Teledentistry Association. In the introduction, he suggests that teledentistry or the remote provision of care is effective. He illustrates this by quoting several papers. However, these are concerned with the diagnosis of dental caries, other dental pathology and identification of malocclusion. Importantly, none of these studies is about the actual provision of interventional clinical care.  We need to consider that this distinction is essential because Smile Direct Club treatment does not involve direct contact with the dentist.

What did he ask?

Firstly, he defined teleorthodontics as:

‘The delivery of health information and orthodontic care across distances using information technology and telecommunications”.

The aims of his study were to

• Objectively assess the clinical effectiveness of teleorthodontic treatment with clear aligners using the Smile Direct Club teleorthodontic platform.
• To measure differences in clinical effectiveness between treatment supervised by general dental practitioners versus orthodontic specialists.
• To consider patient satisfaction.

What did he do?

He obtained a sample of the records of 200 patients who had been treated by Smile Direct Club from the practices of endorsed local providers who had at least five years experience with Invisalign. General practitioners or specialist orthodontists had treated the patients. He did not make it clear whether  the orthodontists/practitioners had treated the patients remotely.  He also asked the patients if they were happy with their treatment.

The main inclusion criteria were that they were aged 18-45 years old and had anterior crowding or spacing that was no greater than 6mm. They also had to have pre and post-treatment photographs and intraoral digital scans. He excluded patients with poor or missing records or those who did not reply to the question about satisfaction.    When he applied these criteria, he excluded 73 (36%) of the sample.

In the next stage, he did a sample size calculation that showed he needed to obtain the records of 50 cases.   The sample size calculation was not precise.  He then randomly selected 50 sets of records for each group.

Finally, he measured the amount of pre and post-treatment crowding using a computer programme. He did not give any details on this. He then carried out a rather complex set of modelling statistics to identify the effectiveness of treatment and the effect of the treating operator group.

What did he find?

I looked carefully at the data that he presented. Unfortunately, he combined the crowding and spacing measurements.  As I feel that these are two different outcome measures, I think that this data is meaningless.  He outlined this statistical analysis in great detail, and I do not have the space to go into this here.

However, his conclusion was:

“Teleorthodontic treatment with clear aligners is clinically effective in the correction of maxillary and mandibular incisor alignment problems (crowding or spacing). There is no difference between this treatment when supervised by general practitioners or specialists”.

He also stated that the treatment was provided at 40% less than the cost for the patient than the cost of similar treatment provided by orthodontists.  However, there was no data on this in the paper.

What did I think?

I initially thought that this paper might be interesting. However, there were many problems with the research methodology. In short, these were:

• It was not clear how the completed cases were selected, and he rejected a high proportion of the treatments because the records were inadequate. As a result, there is a very high risk of selection bias.
• The sample size calculation was not correct.
• I am not sure if the data was recorded blind.
• Combining the outcomes for crowding and spacing was a serious flaw.
• Merely asking patients if they are satisfied or not with treatment is very simplistic.

As a result, I felt that this paper was significantly flawed and I cannot agree with the conclusions.

I also feel that it is relevant that this was published in a predatory journal.

I want to point out that the author clearly stated that he did not have a conflict of interest. The study was funded by the American Teledentistry Association, which is partnered by Smile Direct Club.