Examples of decompression cannulas. (a) Thermoformed cannula in a position in line with the dental arch. This cannula has been prepared before the first surgery time (cyst opening and biopsy) and installed during the intervention. Stitches concern only the surrounding mucosa to “trap” the drain during healing. As an option, if the tube is not flanged, stitches can also transfix the drain. (b) Individual resin cannula in a case of decompression above the maxillary teeth apices. This cannula has been manufactured from an impression taken a week after the first surgery time, and installed afterwards.