Historical aspects of equine cheek teeth exodontia techniques and extraction complications
The type and prevalence of equine post dental extraction problems are closely related to the dental extraction (exodontia) technique used as reviewed by Dixon et al. (2009), Earley et al. (2013), Carmello et al. (2020), Kennedy et al. (2020) and Reardon (2022). Oral extraction in conscious, cast horses restrained by ropes, or under chloroform anaesthesia, or occasionally in standing horses restrained by twitches and leg ropes were widely practiced in the 1800s and early 1900s with obvious welfare problems in non-anaesthetised horses (Easley 2022). Nevertheless, many excellent equine oral extraction instruments and oral speculums were developed at those times. In the mid-1900s, for reasons unknown to the author, the practice of cheek teeth repulsion under chloroform and later, halothane general anaesthesia largely replaced oral extraction and became the standard equine cheek teeth exodontia technique (Fig 1) . The repulsion technique, with its very high reported complication rate of up to 67% (Dixon et al. 2000) or 80% (Carmello et al. 2019) remained the standard cheek tooth exodontia technique until the 1990s.
The use of the (standard) lateral buccotomy cheek teeth exodontia technique in the late 1900s caused a reduced prevalence but a different range of post-operative complications (O’Neill et al. 2011), as well as always requiring general anaesthesia with its attendant costs and risks. The advent of effective and safe equine sedation drugs facilitated the (re)introduction of standing oral extraction in the 1990s (Dixon et al. 2005; Tremaine 2010) using similar oral speculums and extraction instruments developed over 100 years previously. The later introduction of effective regional local anaesthetic techniques (Tremaine, 2007) further enhanced oral extraction techniques, that remains the current equine exodontia technique of choice.
However, oral exodontia requires the presence of a sufficiently strong clinical crown on the affected tooth. The development of less invasive exodontia techniques for teeth with incomplete clinical crowns, including minimally invasive (Steinmann pin) repulsion, minimally invasive transbuccal technique (MITT) (also termed minimally-invasive transbuccal extraction [MTE]) and intra-oral dental sectioning have reduced the prevalence of post-extraction problems of teeth with an incomplete clinical crown as compared to the standard repulsion technique (Langeneckert et al. 2015; Kennedy et al. 2020; Carmello et al 2020). Regardless of the exodontia technique that is used, post-extraction problems can still occur even following careful extractions by skilled veterinarians (Kennedy et al. 2020; Geigert and Bienert 2020).