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Is ClinCheck's analysis of Bolton real?

We all remember our post-graduate years where we had to measure on plaster models the size of each tooth with the caliper in order to be able to calculating the Bolton discrepancy. A tedious job like few others, in which we spent hours and hours.

Fortunately, technology has made this job much easier. Today, the planning programmes have the necessary tools to calculate the discrepancy between the size of the teeth of the two arches. However, these measurements are not always as accurate as we might think. In the process of measuring teeth, there are 3 main factors that can affect their reliability.

Factors affecting its reliability

  • Access to the dental anatomy. Depending on the malocclusion we are scanning, we will not have the same ability to obtain accurate records of the teeth. For example, in a patient with diastemas, the scanner will be able to more accurately capture the entire tooth structure, whereas in a patient with severe crowding and rotations, part of the tooth shape will be "invented" or created by the software.
  • Difficulty in locating a clear reference to determine the mesial and distal side of the tooth. This problem may occur in teeth with irregular anatomy or interproximal wear.
  • Inconsistent measurement protocol. If the parameters for these measurements are not well calibrated, the risk of inaccuracy increases.

Being Invisalign the most widely used brand of aligners globally, the studies to date to determine the accuracy of Bolton's analysis have taken over the programme ClinCheck Pro. From the published studies, the first conclusion we can draw is that the ClinCheck measurement tool is not 100% accurate. However, in each of the studies they use different measurement methods: in one study they use a 3D optical profilometer, which has an accuracy of microns, and in the other study they compare the ClinCheck measurements with the classical manual measurement method. As one might expect, the results of the two studies
were completely different.

  • In the study in which they used the optical profilometerfound that ClinCheck tended to underestimate tooth size, and this difference was greatest in posterior teeth.
  • In the studio where they made manual measurementsThe authors concluded that the ClinCheck gave higher mesiodistal values than the actual values, with the error being higher in molars as well.

What can this lack of precision in the measurement of tooth size affect?

We have to look at the programme from a more critical point of view, we cannot "believe" in Bolton's analysis that ClinCheck calculates. It is possible to take as a reference to find out if there is a defect or excess of tooth material in an arch, but assuming that these measurements are not exactly the same as those of the actual teeth.

On the other hand, at the clinical level, discrepancies between the estimated and the actual interproximal anatomy can lead to unwanted contacts between the teeth that hinder their movements. Fortunately, this problem is easily solvedCheck all appointments for interproximal contact points and use IPR strips to relieve areas where the patient has strong contacts.

Adobes Martin M et al. Reliability of Tooth Width Measurements Delivered by the ClinCheck Pro 6.0 Software on Digital Casts: A Cross-Sectional Study. Int J Environ Res Public Health. 2022 Mar 17;19(6):3581.

Shailendran A et al. Accuracy and reliability of tooth widths and Bolton ratios measured by ClinCheck Pro. Am J Orthod Dentofacial Orthop 2022;161:65-73.

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