During clinical and surgical practice, the dislocation and sliding were less frequent observed in contrast to the original Denhart mouth gag. The Denhart–Hoefert mouth gag has been used in a large number of patients and has not encountered any trauma to the mandible or the teeth so far. After introduction in July 2008, the Denhart–Hoefert mouth gag was used in orthognathic surgery in 250 cases. It is regularly used in bisphosphonate-related osteonecrosis or bisphosphonate-related osteonecrosis risk patient surgery in 150 cases, because of its good controlled force application to the gingiva in edentulous jaw. Additionally, it has been used minimally in another 100 cases of other surgical operations. Manufactured in premium grade stainless steel with a fine satin finish that reduces glare. Author Name Notes: The first year in date range is based on the date of Jennings’ original description of the gag. The second year in the date range is based on the date that the gag was received by the WLM, but it’s fragility suggests that it is more likely to have been manufactured in the first half of the 20th century.

Notes: Tiemann, George, & Co. Catalogue of Surgical Instruments. New York: George Tiemann & Co. 1876:60. The “JS” logo stamped on the object is unknown to the cataloger. It is unlike the caduceus logo of the German manufacturer, Jetter & Scheerer. a Inserting the gag with placing the hole of the pad to the cusp of the canine, b fixation of the pad to the interproximal area with a stop for additional hold The Jennings gag is a modification of the gag introduced in the 1860s by William R. Whitehead, M.D. (1831-1902). Jennings removed the built-in tongue depressor of the Whitehead gag, and simplified the mechanism for opening and closing it. The Whitehead gag has two spring-loaded ratchets. The Jennings gag uses a single ratchet, located on the operator’s right, that can be manipulated by the finger and thumb of one hand. Squeezing the handles together opens the gag. To close it, the ratchet is depressed and the handles pushed apart. Both the Whitehead and Jennings gags are still being made today.

Wood Library Museum of Anesthesiology

Notes: Jennings JE. The complete removal of the tonsil in its capsule (Sluder method) by means of a new tonsillotome. Medical Fortnightly. 1914; 45:56-58.

Notes: Leow A-M, Lun-Jou L. Palatoplasty: evolution and controversies. Chang Gung Med J. 2008;31(4):335-345.It was obvious from the early beginning, that a reliable mouth gag was needed to keep the mouth open continuously. Besides the fact that some of the different models also fixate the tongue, other models showed a more or less tendency to slip, slide away and finally to dislocate. Especially disadvantages of single-sided mouth gags are sliding as well as the dislocation within use [ 3]. Notes: Powers & Anderson. Illustrated Catalogue of Surgical Instruments and of Allied Lines. Richmond, Virginia: Powers & Anderson, Inc., 1917:355. Notes: One mouth gag; Consists of two sculpted, horizontal bars, hinged together at each end, and connected on the right side to a mechanism for adjusting the space between the bars; The mechanism consists of two handles that are hinged so as to stand perpendicular to the bars; These handles hold a ratchet between them; The end of each handle is scored by hatching on its exterior side (for improved grip); In the short physical description the gag is measured in the fully open position; When the gag is fully closed, the height is 8.5 centimeters; Both bars, and both handles, are marked on the interior with the number: “25”; The lower handle is also marked with the logo, consisting of a circle enclosing the letter “J” superimposed on the letter “S”. Interestingly, in early 1907, Colt already mentioned, that there were enough reasons for bringing forward the subject of a mouth gag designed to suit the needs of the general practitioner, surgeon, dental surgeon and anaesthetist. In those times, he already remarked besides the large number of different gags on the market, that a single perfect gag was missing, which supplies all needs [ 4].

All instruments are for Human Surgical use only, if looking for Veterinary Instruments, please visit Notes: Austrian Difficult Airway/Intubation Registry, Virtual Museum of Equipment for Airway Management. http://www.adair.at/eng/museum/equipment/mouthgags/whiteheadobject01.htm. Accessed June 13, 2017. One was introduced in 1914 by St. Louis physician John Ellis Jennings (1863-1935). Jennings' gag is a modification of the Whitehead gag, which had been introduced some fifty years earlier. Jennings removed the built-in tongue depressor of Whitehead's gag, and simplified the mechanism for adjusting it. The Whitehead gag has two spring-loaded ratchets. The Jennings gag has a single ratchet that can be operated by the finger and thumb of one hand. Squeezing the handles together opens the gag. To close it, the ratchet is depressed and the handles pushed apart. Both the Whitehead and Jennings gags are still being made today. Exhibit History Anesthesiologists are responsible for maintaining the patient's respiration and other vital functions during surgery. Mouth gags are sometimes used to hold the patient's mouth open for dentistry, oral surgery and anesthesia. In 1897, Snow [ 6] emphasized, that slipping of mouth gags may embarrass the operator and often seriously deteriorating his results. Therefore, this might present difficulties during surgery and may lead to an interruption of the operation process.

Described from the operator’s perspective, with the ratchet on the right and the handles extending forward. Whitehead gag: invented in 1877 by Walter Whitehead (1840-1913), a surgeon in Manchester, England, [1] consists of two hinged metal frames that wrap around the front of the patient's head and which have sections bent to fit between the front teeth. When spread apart, the frames separate the jaws, holding the mouth open. The desired degree of separation is set and maintained by a ratchet mechanism on each side of the frame. For this purpose, the instrument features a slim wire design that easily accommodates to the face contour. In addition, the device is available in sizes that range from 10.5 to 16.5cm to accommodate pediatric and adult patients.