Speculum Oris: a short history of the mouth gag

A variety of implements have been used to keep a patient’s mouth open for dentistry, oral surgery, and anaesthesia.


Fear often prevents patients from opening their mouth, but many medical conditions require propping the mouth open for treatment or feeding, including the once widespread symptoms of the dreaded tetanus, or lockjaw.

Wooden props and metal specula for oral use feature in medical books as early as the sixteenth century. The Armamentarium Chirurgicum, by Johannes Scultetus (Schultheiss), a German physician and pioneer surgeon (1595-1645), presents illustrations and use of speculum oris, to be used for exploration, difficult extractions, inserting instruments, and to forcibly administer food or medications. The Armamentarium is one of the first books about surgery to be translated in German, English and French, and had a tremendous impact on the development of modern Western surgery.

However, there is some historical evidence that the first forms of mouth gags were crafted as means of torture in medieval times, whether before or concurrently to their use as surgical devices, it’s unclear. The Christian Inquisition used them to keep a prisoner’s mouth open for extended times, leading to dysphagia and jaw pain, or to introduce poisons.

The wicked past of these devices returns in their later use as instrument of slavery in the African-British trade:

“The above [refers to the speculum oris] is used when the slaves are sulky, which frequently happens, that they shut their mouths against all sustenance, and this with a determination to die, and it was necessary their mouths should be forced open to throw in nutriment, that they who had purchased them might incur no loss by their death."

Source: The iron instruments used in the abominable traffic, the slave trade. From the online exhibition: This Abominable Traffic:  Physicians on Slavery. OnView: Digital Collections & Exhibits. 2017. (Harvard.edu). Accessed 25/7/2023

  

Armamentarii Chirurgici Tab XXVI

Speculum Oris as used in 1700s British slave trade 

A diagram published in Thomas Clarkson's The History of the Rise, Progress, and Accomplishment of the Abolition of the African Slave-trade by the British Parliament (1808) shows various instruments of torture and confinement used by slave ship captains and crew members to enforce discipline during the long sea voyage. Among them, the mouth opener as recommended by physicians at the time. It is similar to Heister’s model.

We return now to the gag’s more orthodox medical uses, which actually expanded in the second half of the nineteenth century and early twentieth century.

With the development of ‘inhalational’ anaesthesia by chloroform and nitrous oxide, the mouth gag acquires another level of importance in surgery and dentistry.

Oral surgeons and dentists were used to their patients being awake with sound airway reflexes. Now, oral cavities could be kept open wider and for much longer without the patient feeling discomfort, making procedures easier to perform.

However, anaesthesia increased the dangers of airway obstruction due to muscle relaxation, dislocation, or muscle damage. Moreover, early anaesthetics produced light and inconsistent results, increasing chances of spasms, choking and…bitten fingers for surgeons and anaesthetists!!

A 1907 article by GH Colt, senior anaesthetist at St Bartholomew’s Hospital, shows how important it became to find a reliable mouth gag design that would suit all the needs of general practitioners, surgeons, dental surgeons, and anaesthetists. Protecting the patient from subsequent additional damage was not a big concern yet, however: springs and ratchet catches were usually seen as the solution, or tongue depressors or plates added. The use of tongue forceps or pullers was also advised:

"Should the breathing stop during the administration of Nitrous Oxide Gas, or any other anaesthetic, the forcible pulling forward of the tongue, and the administration of nitrite of amyl within a few seconds after unmistakable signs of something unusual in the breathing have appeared, will in almost every case remove the difficulty." (Underwood’s notes on anaesthetics, as reported in Claudius Ash’s 1893 catalogue under ‘tongue forceps’).

More recent bilateral props reduce strain to TMJ and masticatory muscles more effectively, after lengthy dental or surgical procedures.

ADAQ’s historical collection includes a few old mouth gags that never fail to unsettle visitors who are non-dental professionals, and sometimes dentists too!

MOUTH PROPS

The simplest mouth props or gags were either made using vulcanite or lignum vitae, one of the hardest and most dense wood known, sometimes with soft rubber edges at the contact points with teeth. [ADAQ D76]

A long string was tied around the cinched waist, with the ends of the string left hanging out of the patient’s mouth, so that the gag could be retrieved easily if it dislodged. These gags were sold as early as 1875 by Claudius Ash & Sons, in three sizes, and were still available in the 1930s.

For anaesthesia, the prop was placed in the patient’s mouth, then the facepiece of the administering apparatus adjusted. A few inspirations of pure air before closing the stopcock would ‘beget confidence’ in the patient.

Lignum vitae (Guaiacum) originates from Central America. Some of its uses over time included: ship parts, truncheons for the British police, pulleys and wheel shafts, kitchen pestles, lawn bowls and croquet mallets. Lignum vitae resins were also used in medicine for syphilis, tuberculosis, and asthma; its extracts even featured in dentifrices and perfumes since the Renaissance, for its fragrance similar to sandalwood.

MAUNDERS SCREW GAG

‘For rapidly forcing open the mouth’, this screw-shaped appliance is credited by some to Austrian surgeon, Dr. Franz von Pitha (1810-1875). However, it commonly bears the name of Mr Maunders, who first described the use of a hard wood gag with helicoidal grooves in the 1850s.

It consists of a conical boxwood wedge with a helical spiral groove of increasing diameter and a distal holder (which is broken off in our gag). It is inserted between a gap in the front teeth.

Where contraction of the muscles of mastication is the result of an impacted wisdom tooth, occurring as it does in early life, the teeth at the front of the mouth are almost always firm and will bear the use of this instrument.

Metal Maunders screw gags are still available today, for use in procedures involving oral and nasal cavities.[ADAQ D227]

HEISTER’S MOUTH OPENER

A screw-like device appears in an illustration of the 1719 manual Chirurgie, by Lorenz Heister (1683-1758), a military surgeon who had treated many patients with tetanus. Heister recommends mouth openers and tongue depressors use for ‘spasms of the jaw’, as with tetanus or peritonsillar infections. [University of Queensland Collection]

The device maintains Heister’s name to this day, but it’s still unclear whether he actually devised the instrument himself.

In 1893, we find Claudius Ash & Co lists it simply as ‘mouth opener’, but for anaesthetics purposes: it was usually introduced where teeth were missing, but the thin blades could be ‘insinuated’ between clenched front teeth.

CROFT’S ADJUSTABLE SIDE GAG

This nickel-plated steel device shows one of the improvements made to the popular Mason’s adjustable side gag, which featured two curved shanks hinged together as a plier, with a ratchet-type mechanism across both and catch pin for release. The two concave cups accommodate the back teeth, in some versions these are coated in soft rubber. [ADAQ D362]

 

Simple mouth props

Claudius Ash & Sons 1893 Catalogue

Mounders Gag

Mason's Gag

Mouth Opener

REFERENCES

Claudius Ash & Sons. Dental Catalogue. 1893. ADAQ Archives

Colt GH. The Gag. The Lancet. Vol 170, I- 4389, 12 October 1907, pp. 1011-1017. https://www.sciencedirect.com/science/article/pii/S0140673600305165

Haridas RP. The Heister Mouth Gag or ‘Speculum Oris.’ Anaesthesia and Intensive Care. 2015;43(1_suppl):40-46. doi:10.1177/0310057X150430S108

Hopkins, Philip M., and Alistair G. McKenzie (ed.), 'The history of anaesthesia', in Jonathan G Hardman, Philip M Hopkins, and Michel M.R.F Struys (eds), Oxford Textbook of Anaesthesia, Oxford Textbook (Oxford, 2017; online edn, Oxford Academic, 1 Apr. 2017), https://doi.org/10.1093/med/9780199642045.003.0031, accessed 25 July 2023

Hoefert S. The evolution of mouth gags. Presentation of a new modified denhart mouth gag. J Maxillofac Oral Surg. 2013 Dec;12(4):475-9. doi: 10.1007/s12663-012-0417-z. Epub 2012 Aug 29. PMID: 24431892; PMCID: PMC3847009