The Inaccuracy of Dental Floss for Checking the Intensity of a Proximal Contact


For many dentists, floss still seems to be the method of choice for checking the intensity of pressure between proximal contacts after restorative procedures. After all, snapping floss into and out of contact is the technique most of us learned in dental school, based on the supposition that an accurate evaluation of how tight that contact is can be gained by the amount of resistance detected.

Unfortunately, the use of floss is often far less accurate than we should be comfortable with. To start with, the thickness of floss varies widely enough from brand to brand that the perceived tightness of contact can change significantly depending on the type of floss used (1).

Beyond that, the specific way in which floss is handled can make it less reliable. Both twisting the floss and stretching it until taut change its thickness and flexibility. This, in turn, can make even the same floss behave differently and give different results depending on relatively minor differences in how it is used.


With these factors in mind, it isn’t hard to see why research suggests floss is a relatively inaccurate means of ensuring the presence of ideal proximal contacts. Instead of relying solely on floss, I designed the Gray Final Polishing Strip to be the perfect way to confirm that Interproximal Relief has been restored. Without the material drawbacks of floss, ensuring that this thin interproximal polishing strip can pass through the contact space with light resistance is a reliable way to simultaneously remove surface roughness and check for proper contact pressure. By combining this with a final floss, shim stock, or articulating film check, you can always be sure of the accuracy of your proximal contact adjustments.


Figure 1: Adjust the proximal contacts of a new crown in the mouth using the Black Diamond Strip prior to cementation.


Figure 2: After the crown has been cemented, polish the contact areas and confirm Interproximal Relief using the Gray Final Polishing Strip. It should pass through the contact with light resistance.

1)      Teich ST, Joseph J, Sartori N, Heima M, Duarte S. Dental floss selection and its impact on evaluation of interproximal contacts in licensure exams. J Dent Educ. 2014;78(6):921-926.

2)      Hansen, Paul & Atwood, Ariel & Shanahan, Mallory & Beatty, Mark. (2019). The accuracy of clinician evaluation of interproximal contacts using different methods. The Journal of Prosthetic Dentistry. 123. 10.1016/j.prosdent.2018.10.029

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