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complications, outcomes and limitations of the technique are reported.
Materials and methods
Case details of 22 dental extractions on 20 horses utilising PMMA at the Marion DuPont Scott Equine Medical Center, Leesburg, Virginia from October 2011 to August 2016 were examined retrospectively. Extractions were considered successful if the entire targeted tooth was extractedwithout requiring repulsion to remove the tooth or residual fragments. The authors performed all procedures. Case information extracted from medical records included signalment, affected tooth (Floyd 1991), clinical signs, diagnostic imaging, technical difficulties, post-operative complications and time to resolution of clinical signs. Each tooth extraction using PMMA was considered a separate procedure, with two horses undergoing two extractions each. Clinical diagnoses were made using visual oral and dental
examination, oral endoscopy, radiography and, more recently, standing computed tomography (Pegaso HD CT)
2.All procedures were performed with animals sedated and standing in stocks. Sedation was achieved using detomodine hydrochloride (Dormosedan)3 i.v. at 0.01 mg/kg bwt or xylazine hydrochloride (Rompun)4 i.v. at 0.4 mg/kg bwt alone, or in combination with butorphanol tartrate (Torbugesic)5 i.v. at
0.01 mg/kg bwt. Perioperative analgesia was provided with flunixin meglumine (Flunazine 1.1 mg/kg bwt i.v.)6,or phenylbutazone (ButaJect 2.2 mg/kg bwt i.v.)7. Perioperative antimicrobial coverage with ceftiofur crystalline (Excede 6.6 mg/kg bwt i.m.)8 was administered in cases with pre-existing sinusitis, as broad spectrumantimicrobial coverage is advised in these cases to reduce the risk of bacteraemia (Bartmann et al. 2002; Bienert et al. 2003). Regional anaesthesia was performed on either the maxillary or mandibular nerves, as described elsewhere (Tremaine 2007). Initially, perineural injection of the maxillary nerve was performed blindly and latterly under ultrasound guidance (O’Neill et al. 2014). Following placement of a full mouth speculum, the mouth was rinsed with copious amounts of water and a pressurised stream of dilute betadine and dental pick used to dislodge the feedmaterial. Polymethymethacrylate powder was then mixed until it
formed a thick slurry and continually mixed until it became mouldable. Fracture spaces were packed with PMMA to the level of the occlusal crown and allowed to harden (Fig 1). Intraoral dental extraction was then performed as described in detail elsewhere (Tremaine 2004; Dixon et al. 2005). Occasionally following cheek tooth spreading, PMMA packing would loosen and fall out of the fracture space. In these instances, new PMMA was prepared and allowed to harden prior to applying extraction forceps. Trephination of the conchofrontal or maxillary sinuses was performed to facilitate sinus lavage, or to enable repulsion, where required (Barakzai and Dixon 2014). Following sinus lavage and/or tooth repulsion, skin incisions were opposed primarily using sterile stainless steel skin staples. Following extraction, tooth alveoli were lavaged with
dilute betadine solution. Dental impression material (Splash! super hydrophilic impression material)9, impregnated with 1 g crushed metronidazole powder10, was then mixed together and packed in the empty alveoli and allowed to harden. Metronidazole was chosen due to the reported prevalence of anaerobes in dental related sinusitis cases (Bartmann et al. 2002; Bienert et al. 2003).
© 2017 EVJ Ltd
a)
b)
Fig 1: Oral endoscopy images of a sagittal fractured maxillary cheek tooth. a) shows the tooth before and b) after filling with PMMA.
Digital photographs of extracted teeth were taken using
a digital camera11 (Fig 2). Tooth measurements were made using digital image software (ImageJ version 1.49)12 and calibrated against a ruler in the image. Teeth were measured longitudinally from the longest root to the ipsilateral occlusal surface and transversely across the widest point of the occlusal surface. Fracture depth was measured from the most apical extent of the carious lesion to a point in line with the occlusal surface, approximately half way between each fragment and transversely at the widest point. Follow-up information was obtained from owners at 3–
48 months post-operatively via email or telephone conversation. Enquiries were specifically made regarding time to resolution of clinical signs, post-operative complications and return to intended use.
Data analysis Summary statistics and histograms of tooth measurement data were performed. Tooth measurements are presented as
mean s.d. Comparison of intraoral extraction success with other categorical variables was not performed as this was not
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