Prefabricated facemasks are commonly used in Class III treatment. Because the fit of the chin cup is not customized for each patient, however, poor adaptation often causes skin irritation and even mild swelling, with a negative effect on compliance.
Suggestions for avoiding such irritation have included placing a soft, natural-fiber cloth between the chin and the cup or taking an alginate impression of the chin and building a silicone support over the chin pad. The former option may not provide adequate relief, and the latter adds laboratory costs and another appointment for delivery of the mask to the patient.
We recommend the following procedure for chin-cup customization:
1. Remove the felt sticker from inside the prefabricated chin cup.
2. Place a putty-consistency polyvinyl siloxane (PVS) inside the chin cup, adapting the material beyond the borders of the cup to assure better retention (A)
3. Use the chin cup itself as an impression tray, pressing it against the chin and holding it for a few seconds. It is not necessary to hold it until the impression material hardens.
The impression will remain firmly attached, forming a tailor-made chin cup (B)
This method is simple, quick, and inexpensive. PVS is highly biocompatible and is commonly available in most orthodontic offices. Our patients have reported improved comfort and better stability with their customized chin cups. Although most have worn them directly against the skin with no irritation, a soft, thin cotton or silk cloth may be used with the modified chin cup to avoid any cutaneous reaction in highly sensitive patients.