Here you can buy various medical instruments like a dental retractor and mouth spreader. Most of these devices have been used by dentists and oral surgeons to treat patients. It is not possible to close the mouth with a dental retractor mouth spreader.
These mechanical instruments can also be used very well as a BdSM mouth gag, like they was used already in the middle-age as a torture instrument. Please keep in mind that you do not open the mouth spreader too fast and too wide to avoid overstretching of the muscles. Dental retractor mouth spreader buy low-priced at Fetischladen.ch.