June 11, 2018

Invisalign patients are happy!

Invisalign is an established form of orthodontic treatment.  But are Invisalign patients satisfied with their treatment? 

We know that dissatisfaction with the appearance of teeth is one of the main reasons that patient seek orthodontic care. We also know that following fixed appliance treatment most patients are happy with their dental aesthetics. They also have an improved oral health quality of life.  However, no studies have looked at the effects of Invisalign treatment on oral health quality of life (OHRQoL).  A team from Alberta, Canada did this study. The AJO-DDO published it.

Patient satisfaction and quality of life changes after Invisalign treatment

Camila Pacheco-Pereira, Jeremy Brandelli, and Carlos Flores-Mir

Am J Orthod Dentofacial Orthop 2018;153:834-41. DOI https://doi.org/10.1016/j.ajodo.2017.10.023

What did they ask?

They asked this simple question

“What is the level of patient satisfaction and change in OHRQoL immediately after Invisalign treatment”?

What did they do?

They planned an ambitous observational cohort study.  They recruited patients from 4 private orthodontic practices in Canadian cities.  Importantly, their main inclusion criteria was adults whose last appointment, before completion of their treatment, was between October 2014 and October 2016.  They only included patients over 16 years old.

If the patient agreed to take part in the study, they were asked to complete two questionnaires. These were the Dental Impacts on Daily Living and the Patient Satisfaction Questionnaire.  They analysed this data with relevant and complex statistical analysis.

What did they find?

The survey ran over a 22 month period. 94 patients decided to take part, but three did not complete the survey. As a result, they had a sample of 81 patients, from 4 practices.  Importantly, they did not record how many patients were asked to take part in the study. I will return to this later.

They provided a large amount of data. I have extracted the main points.  These were:

  • The scores for appearance, eating and chewing improved.
  • The doctor-patient relationship was the most important factor for patient satisfaction.
  • Overall the patients were satisfied with their treatment.
  • Pain and discomfort while wearing the aligners were factors of dissatisfaction.
What did I think?

This study is one of the first to attempt to investigate the effects of clear aligner treatment. As a result, I thought that the findings were interesting and relevant to practice. Unfortunately, this study has one major issue.  This is the response rate. The authors state that they did not gather data on the number of patients who were approached to take part in the study. They discuss this in some detail and point out that “the orthodontists were hesitant to implement the survey”. Furthermore, they also estimate “that more than 50% of the approached patients refused to participate”.  This explains the low number of participants in the study.  As a result,  the study must suffer from considerable bias. Unfortunately, we do not know the direction of the bias.

Finally, we need to consider whether these results are useful. My feeling is that it is difficult to interpret the results of this study and perhaps we should consider this to be pilot data. Investigators can use this for other larger studies.  Nevertheless, the results are similar to other studies and may provide us with information. One finding that I thought was interesting was that satisfaction was related to the doctor-patient relationship. This has been found in other studies of health care provision. I wonder where this leaves us with “do-it yourself orthodontics“, Smile Direct Club and Invisalign stores?

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Have your say!

  1. Avatar

    This is an interesting stud, I think provokes to open our minds to the innovations. It is an invitation for many to leave the comfort zone and develop new skills and competencies. I do not agree with the statement … “As a result, the study must suffer from considerable bias. Unfortunately, we do not know the direction of the bias.” On the contrary, it shows that there was control over confounding variables.

  2. Avatar

    Excellent critique…totally agree with the statement re: bias. 50% not participating might imply that they are not happy with the treatment or outcome! That’s a more realistic scenario

  3. Avatar

    Very interesting. I am sure this study can we well utilized as a pilot study. And I endorse that the patient satisfaction is hundred percent related to the doctor patient relationship!

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