Invisalign is a removable orthodontic system, where abnormalities like crooked or uneven teeth can be corrected in an aesthetic and comfortable manner. This orthodontic treatment consists of wafer-thin, transparent aligners that fit snugly on teeth and gently move them in place.
Researchers have found in a new research that one in every 6 patients (17.2%) needed to switch from Invisalign to braces to finish their treatment. Further Invisalign treatment required an average of 2.5 refinement scans. Only 6.0% of the patients completed their Invisalign treatment without a single refinement scan.

The new study has been published in the American Journal of Orthodontics and Dentofacial Orthopedics
This retrospective clinical study aimed to determine what percentage of patients switched from Invisalign to braces to finish treatment. We also examined the number of refinement scans per treatment and the estimated vs actual length of treatment.
A general perception is that incorporating more Invisalign improves an office’s efficiency. The reasons most often mentioned include greater delegation, less chair time, fewer visits, and extended appointment intervals.Although the potential benefits are undeniable, if the teeth fail to track in the aligners, then even simple malocclusions can result in multiple refinement scans or the switch to braces. Therefore, in reality, an office’s improvement in efficiency by using Invisalign is only as good as its effectiveness.
Records from 500 patients (average age 33.6 years) that started with Invisalign Full or Invisalign Teen were gathered from 2 orthodontic offices and evaluated. Data was collected from the doctors’ consultation notes, treatment notes, and Invisalign Web site databases. There were 2 independent variables: gender (male and female) and age groups (aged <20 years, 20-30 years, and >30 years).
Results
One in every 6 patients (17.2%) switched from Invisalign to braces. Invisalign treatment required an average of 2.5 refinement scans, and only 6.0% of patients could complete their treatment without a single refinement scan. The average length of Invisalign treatment was 22.8 months, this was 5.1 months more than the estimated length. The average number of aligners was 64.1, but for the patients that switched to braces, the average number of aligners was 80.6 plus an additional 6.9 months of braces. There was no statistical difference between gender or age group and the conversion to braces. However, patients in the oldest age group had a significantly greater number of refinement scans.
Researchers are likely overestimating an office’s efficiency using Invisalign. On average, an Invisalign patient will require approximately 2-3 refinement scans and 2 years of treatment, and there should be a reasonable expectation that braces may be needed.
Reference:
Neal D. Kravitz, Bassel Dalloul, Yara Aba Zaid, Chandani Shah, Nikhilesh R. Vaid. What percentage of patients switch from Invisalign to braces? A retrospective study evaluating the conversion rate, number of refinement scans, and length of treatment. Open AccessPublished:December 18, 2022DOI: https://doi.org/10.1016/j.ajodo.2022.03.016