Letters to the editor

Chewies (Invisalign, Align Technology, Birmingham) are small soft plastic, silicone-like material, cylindrical in shape, not edible, and reusable devices. They are made of a material called styrene copolymer. They are used to remove the air bubbles between the Invisalign and teeth to make sure that the aligner is seating perfectly, and providing balanced forces on all teeth. Chewies are available in different colours and some of them have favourable scents.^1,2 Many companies now sell similar items with different features, for example some are edible.

Patients are instructed to use them every time they take out the aligners, and before bedtime. Different manufacturers have different instructions. One website recommends using them for 5 minutes twice a day, while others recommend using them each time the aligner is put on.^1,2 Several websites claim that these accessories can somehow speed up the treatment, by enhancing the fit of the aligner and removing air gaps, which results in moving teeth more effectively.^1,2 Chewies are used to ‘overcome poor tracking or aligner lag’. All this might encourage patients to use these devices excessively and induce their misuse because patients may think that they will achieve aesthetic results sooner with more use of Chewies; however, there are no clinical studies or scientific evidence to support this practice.