424
EQUINE VETERINARY EDUCATION / AE / AUGUST 2019
TABLE 1: Summary tooth measurement data
Fx depth (mm)
IOE Successful mean (n = 15) IOE failure mean (n = 3) Overall mean* (n = 18)
30.86 34.33 31.47
Tooth
length (mm) 53.07
61.33 54.53
Fx width (mm)
19.15 14
18.47 Tooth
width (mm) 36.54
31 35.8
* For some teeth, not all measurements were available. For individual tooth data, see Supplementary Item 2. Fx, fracture.
required. The horse with persistent sinusitis for 109 days following extraction did not present for routine recheck at 2 weeks. When examined at 109 days, sequestered right ventral concha bulla bone was removed via the nasal passages and the sinusitis subsequently resolved. A total of 82% of teeth (18/22) were measured following extraction (Table 1). Mean tooth length was
54.53 10.79 mm, mean fracture length 31.47 8.16 mm, mean tooth width 35.80 10.16 mm and mean fracture width 18.47 6.20 mm. The mean ratio of fracture depth to tooth length was 0.59 0.15 and mean ratio of fracture width to tooth width 0.53 0.13. Individual tooth measurement data are listed in Supplementary Item 2. There were two cases with maxillary nerve block
complications. One developed a retrobulbar haematoma and periocular swelling which resolved in 24 h. This was treated with topical triple antibiotic ophthalmic ointment (Neomycin and Polymyxin B Sulfates and Bacitracin Zinc Ophthalmic Ointment USP)14 applied to the cornea and a pressure bandage placed over the eye for 12 h. The other developed ocular pruritis, blepharospasm, conjunctivitis and a small superficial corneal ulcer. Resolution was achieved following 4 days of treatment with a face mask to protect the
eye, triple antibiotic ophthalmic ointment every 6 h and flunixin meglumine (1.1 mg/kg bwt i.v. q. 12 h). Follow-up was available for 18 cases at a median of 20.5 months post-tooth extraction (range 3–48 months).
Discussion Utilising PMMA to fill large defects in displaced sagittal fractures was successful in 73% of cases and therefore we found it to be an effective method of assisting intraoral extraction of this type of cheek tooth fracture. In our clinical experience, attempting oral extraction of displaced sagittally- fractured cheek teeth without stabilisation usually resulted in iatrogenic fracture of one or both of the fracture fragment clinical crowns, similar to what has been reported (Dixon et al. 2005). The study population consisted of middle-aged horses
with a median age of 15 years, similar to a survey based report of sagittal fractured cheek teeth (Taylor and Dixon 2007). It is likely that this reflects the duration of progression of infundibular caries as the majority (21/22) of teeth extracted had an appearance consistent with grade four infundibular caries. The one mandibular cheek tooth had a vertical fracture coursing through pulp chambers one and two (Du Toit et al. 2008). No breed predilection was observed throughout the study; the higher number of Warmbloods is likely to reflect the hospital referral population. The majority of cases were geldings (70%) and the reason for this is unknown.
© 2017 EVJ Ltd The prevalence of clinical signs (64%) in this case series is
consistent with a previous study of idiopathic cheek tooth fractures that reported 70% in maxillary midline fractures (Taylor and Dixon 2007). In that study, quidding, bitting/ behavioural problems and halitosis were the main clinical signs with only one case having purulent nasal discharge. In the current study, 41% of horses had purulent nasal discharge and confirmed sinusitis, indicating a greater propensity for clinical progression of this fracture type in our study population. Sinusitis may be the result of either extension of periodontal infection or pulpar exposure. In a report of 31 idiopathic cheek teeth fractures, 42% of extracted teeth had evidence of pulpar exposure (van den Enden and Dixon 2008). In the present study, it was assumed that pulpar exposure through the common chamber had occurred. Examination of extracted teeth apices often revealed loss of the periodontal ligament as a result of infection caused by feed material packing into the fracture plane. To our knowledge, displacement and depth of sagittal
fractures have not been previously described. The fractures in this report were highly displaced with a mean fracture depth of 31 mm and a mean fracture width of 18 mm. This allows significant feed packing into fracture spaces, leading to fermentation and displacement of the tooth fracture fragments. In the one case in which computed tomography was performed (Fig 4), buccal and palatal displacement of the exposed crown was evident indicating remodelling of the distal periodontal ligament and alveolar bone to accommodate the expansion of the fracture space. All maxillary cheek teeth in the study had grade 4
infundibular caries (Honma et al. 1962). The aetiopathogenesis of sagittal fractures in maxillary cheek teeth is thought to be the result of coalescing infundibular caries (Dixon and Dacre 2005). In turn, infundibular caries may result from cemental hypoplasia, a process whereby the central apical portion of infundibular cement is incomplete (Staszyk et al. 2015). Triadan maxillary 09 cheek teeth are more prone to hypoplasia and it is thought that this is because of their relatively earlier eruption precluding complete filling of the infundibula with cementum (Staszyk et al. 2015; Suske et al. 2016a). The hypoplastic infundibula are then potentially vulnerable to carious damage when exposed through attrition (Suske et al. 2016b). A higher percentage of Triadan 09 teeth were affected in the present study, consistent with the hypoplastic infundibula hypothesis and previous reports of cheek teeth fracture patterns. The one mandibular cheek tooth in this study had a miscellaneous fracture pattern (Dacre et al. 2007). This horse presented with quidding and had radiographic evidence of periapical infection. The exact pathogenesis of the fracture is unknown in this case. In a previous report of a similar fracture type, no underlying reason for the fracture was found histologically (Dacre et al. 2007).
Fx depth/ tooth length
0.60 0.55 0.59
Fx width/ tooth width
0.54 0.45 0.53
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