EQUINE VETERINARY EDUCATION Equine vet. Educ. (2019) 31 (8) 421-426 doi: 10.1111/eve.12796


Original Article


Extraction of 22 equine cheek teeth with displaced sagittal fractures using polymethylmethacrylate stabilisation (2011–2016)


D. J. Pearce* and J. A. Brown Marion duPont Scott Equine Medical Center, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic and State University, Leesburg, Virginia, USA. *Corresponding author email: duncanp7@vt.edu


Keywords: horse; dental extraction; equine cheek tooth; polymethylmethacrylate (PMMA); sagittal fracture


Summary Displaced sagittal cheek tooth fractures are a cause of oral pain, quidding and apical infection. Intraoral extraction is the preferred technique to remove affected teeth, but can be difficult due to displaced and friable fracture fragments. Stabilising fracture fragments via filling of the fracture space with polymethymethacrylate (PMMA) prior to removal may be a useful method to facilitate intraoral extraction. Case details were examined retrospectively. A total of 22 cheek teeth required extraction in 20 horses because of displaced sagittal fractures. Clinical diagnoses were made using oral examination, oral endoscopy, skull radiography and computed tomography. All procedures were performed in standing, sedated horses in stocks. Fracture spaces were cleaned and packed with PMMA and teeth removed using a routine intraoral extraction technique. Digital photographs of extracted teeth were taken and tooth measurements calibrated using digital image software. Intraoperative difficulties, as well as post-operative complications were recorded. A total of 21 maxillary and one mandibular cheek teeth were extracted. All maxillary teeth had advanced infundibular caries. Intraoral extraction was successful in 16 cases; six were unsuccessful and required repulsion due to tooth fragmentation or abnormal dental anatomy. In 11 cases, maxillary or conchofrontal sinus trephination was performed to either treat sinusitis, repulse the tooth, or both. Two horses developed short-term complications following local anaesthesia of the maxillary nerve. The mean ratio of fracture depth to tooth length was 0.59 and mean ratio of fracture width to tooth width 0.53. The limitations of the study are its small sample size, retrospective nature and lack of control group to compare extraction success in PMMA and non-PMMA groups. It was concluded that using PMMA to stabilise displaced sagittal fractures in equine cheek teeth is a simple, effective method of facilitating intraoral extraction and may reduce the need for more invasive procedures.


Introduction


Fractures of equine cheek teeth are a cause of oral pain and risk for apical infection, particularly when fracture planes involve pulp chambers (Dacre et al. 2007). They can be of traumatic origin, iatrogenic, or may have no known history of trauma. The latter group have been termed ‘idiopathic’ (Dixon et al. 2000). Idiopathic cheek teeth fractures have a low prevalence (0.4%) in the general horse population and varying clinical signs range from mild halitosis to severe apical


infection with associated draining tracts or sinusitis (Taylor and Dixon 2007). Studies of idiopathic maxillary cheek teeth fracture configurations have revealed buccal slab fractures to be the most prevalent followed by sagittal (or midline) cheek teeth fractures (Dixon et al. 2000; Dacre et al. 2007). Sagittal fractures in maxillary cheek teeth typically course through both infundibulae and have been shown to be the result of coalescence of severely carious infundibulae with the 109 or 209 cheek teeth commonly affected (Dixon et al. 2000, 2014; Dacre et al. 2007; Taylor and Dixon 2007; Bienert and Bartmann 2008; van den Enden and Dixon 2008). Approximately 70% of sagittal fracture cases may be symptomatic, with clinical signs including quidding, behavioural problems and halitosis (Taylor and Dixon 2007). In more advanced cases significant displacement of the fracture fragments occurs secondary to food packing into the fracture space. Despite the common nature of sagittal fractured cheek teeth, an extraction technique specificto this pathology has not been described. Standing intraoral dental extraction is the treatment of


choice for diseased cheek teeth in horses (Prichard et al. 1992; Dixon et al. 2005; O’Neill et al. 2011; Reichert et al. 2014). Intraoral extraction may not always be possible in teeth with pre-existing fractures or dental caries, due to significantly reduced crown surface area and the friable nature of fracture fragments (Tremaine 2004). Additionally, deformed or malformed roots are often present and become fractured when buccal and palatal or lingual fragments are compressed. Alternatives to conventional oral extraction include traditional buccotomy, tooth repulsion and minimally invasive transbuccal intradental screw placement (Prichard et al. 1992; O’Neill et al. 2011; Langeneckert et al. 2015). These techniques can be associated with higher complication rates than conventional oral extraction, involve general anaesthesia, or require specialised equipment. Polymethymethacrylate consists of polymerised methyl


methacrylate monomers and has several biological uses (Cruz et al. 2006; Hirvinen et al. 2009). It is available in powder form (Technovit powder and liquid)1 and sets to a hard substance via an exothermic polymerisation process within 2–10 min after mixing with a hardener. The purpose of this report is to describe utilising PMMA to reinforce the clinical crown of sagittally-fractured displaced cheek teeth as an aid in intraoral extraction and secondarily to document the clinical appearance of displaced sagittal cheek teeth fractures. The technique is described, intraoperative difficulties discussed and post-operative


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