Traumatic Dentoalveolar and Maxillofacial Injuries in Cats

Abstract

Practical relevance:

Maxillofacial and traumatic dentoalveolar injuries can cause pain and inflammation, and reduce function of the mouth, impacting a cat’s quality of life. Many traumatically induced feline fractures have been reported to involve the mandible or skull and, in cats with maxillofacial trauma, traumatic dentoalveolar injuries are particularly prevalent. Traumatic dentoalveolar injuries can also often be found in otherwise healthy cats.

Clinical challenges:

Some traumatic dentoalveolar injuries require emergency treatment; timely recognition and managment is therefore important for achieving the optimal outcome. Multiple approaches exist for the management and repair of maxillofacial traumatic injuries. However, those for traumatic dentoalveolar injuries may be more limited.

Audience:

This review is aimed at feline and general practitioners, as well as veterinarians with expertise in dentistry.

Evidence base:

The authors draw on their clinical experience and evidence from the literature, where appropriate, to produce an overview of foundation guidelines. It is hoped that this will serve as a stimulus for deeper consideration as to what constitutes ‘best practice’ principles for cats with traumatic dentoalveolar and maxillofacial injuries.

How frequent are these injuries and what is the goal?

The prevalence of traumatic dentoalveolar injuries has been reported to be as high as 27.0% among otherwise healthy dogs and cats, ¹ and as high as 72.1% in patients with concurrent maxillofacial trauma. ² in cats treated for high-rise syndrome, the prevalence has been reported at 73.1%.3 There appears to be a hyperbolic relationship between age and frequency of dentoalveolar injuries. The canine teeth, in particular the maxillary canine teeth, due to their role in apprehension and defence, are more vulnerable to trauma than other teeth. in cats, the quantity and severity of traumatic dentoalveolar injuries tend to increase in patients with concurrent maxillofacial fractures.

Studies on the prevalence of maxillofacial fractures in cats tend to report on small populations and frequently focus on the occurrence of mandibular injury. As high a proportion as 26.9% of all traumatically induced fractures in cats have been reported to involve the mandible or skull. ⁴ Mandibular fractures are more commonly reported to constitute 14.5–23.1% of all fractures in the cat.^4,5

While maxillofacial injuries may be more obvious, traumatic dentoalveolar injuries should also be expected in these patients. Aside from forces associated with chewing and mastication, traumatic dentoalveolar injuries and maxillofacial fractures may originate from altercations with other animals, motor vehicle accidents, high-rise syndrome injury or may simply be sustained during playful activity.

Multiple treatment approaches exist for the management and repair of traumatic maxillofacial injuries. Those for traumatic dentoalveolar injuries may be more limited. Notwithstanding, the ultimate goal in these patients is a rapid return to a functional, pain- and inflammation-free occlusion.

Traumatic dentoalveolar injuries

Traumatic dentoalveolar injuries are a collection of specific injuries to the tooth and/or the tooth-supporting structures sustained as a direct result of a traumatic force (see page 916). Unaddressed, these injuries may cause years of pain and inflammation. The most appropriate treatment for some traumatic dentoalveolar injuries is best rendered on an emergency basis, when possible. Therefore, timely recognition and treatment of these injuries is important for an optimal outcome.

Because of the pet-owning population’s increasing appreciation for the function and appearance of their pet’s oral cavity, the following discussion is targeted toward efforts to preserve the dentition with endodontic treatment and tooth stabilization, whenever possible. Rather than endodontic therapy being considered an alternative to extraction, we consider extraction to be an alternative to endodontic therapy. When endodontic treatment is not possible or desirable to the client, extraction of the tooth may be considered. it is useful to discuss traumatic dentoalveolar injuries individually, but it should be kept in mind that, in some cases, several injuries will affect a tooth concurrently.

Enamel infraction

An enamel infraction is a crack confined with- in the enamel; no tooth structure is lost. This type of injury is asymptomatic and may be an incidental finding on oral examination. The presence of the infraction does not lead to any negative consequence and does not require treatment. However, the tooth should be monitored over time for crack propagation. Cracks that extend into dentin and/or the root may be painful and may require treatment.

Enamel fracture

An enamel fracture is defined as loss of tooth structure confined to the enamel. Because no dentinal tubules are exposed, this is not painful and does not compromise the pulp. Radiographic examination of the pulp and periodontium will show no abnormalities.

Treatment of enamel fractures should include smoothing of any sharp enamel edges (odontoplasty) with a diamond-coated bur of appropriate size in a water-cooled, high-speed handpiece. The trauma that caused the enamel fracture may also have been forceful enough to cause a concussion to the pulp and the tooth should be monitored both visually and with intraoral radiographs for pulpitis for a period of at least 1 year.

Enamel–dentin (uncomplicated) fracture

Feline enamel is quite thin and in some locations may extend to no more than 0.1 mm in depth (Figure 1). ⁷ Thus, most fractures will extend into the dentin. due to exposure of nerve fibers within dentinal tubules, enamel– dentin fractures cause pain. if the injury is acute, there should be no significant radiological findings. Acutely injured teeth are treated with odontoplasty and the application of a restoration to cover the exposed dentinal tubules. The type and degree of restoration utilized will vary depending on the degree and location of the trauma.

Figure 1.

Cross section through the right maxillary canine tooth (104) near the cusp, highlighting the thin enamel (E) in cats. D = dentin

Unfortunately, most injuries have been present for months to years before being diagnosed. if the tooth is not identified and treated quickly, the odontoblasts affected by the exposed dentin may die. The pulp may respond by recruiting undifferentiated mesenchymal cells to replace the non-vital odontoblasts. These new odontoblasts can produce tertiary dentin that will fill the exposed dentinal tubules and protect the pulp so that the inflammation can resolve. in this scenario, treatment is as described above for an acute injury.

However, if bacteria penetrate the dentinal tubules or if the pulpitis becomes irreversible the result may be pulp necrosis, which will extend apically to involve the apical periodontal ligament and supporting apical bone. At this point the patient is suffering from a severe inflammatory disease of the periodontal ligament and bone in the apical region (apical periodontitis). This manifests radio- graphically as rarefying osteitis (periapical lucency) (Figure 2). in the chronic lesion there may also be radiologic evidence of root resorption and condensing (sclerosing) osteitis. When apical periodontitis is present, treatment typically consists of root canal therapy (see box above).

Figure 2.

Radiograph of a periapical lucency of the mesial root of the left maxillary third premolar (207) secondary to an enamel–dentin–pulp fracture and pulp necrosis in a cat. Courtesy of Wade Gingerich, Bonita Springs, FL, USA

Enamel–dentin–pulp (complicated) fracture

An enamel–dentin–pulp fracture is a crown fracture that causes clinically visible pulp exposure (Figure 3). These fractures are the most common traumatic dentoalveolar injury in cats. Because the distance between the pulp chamber and the surface enamel is quite small in the canine teeth of cats, most fractures lead to pulp exposure.

Figure 3.

Pulp exposure secondary to an enamel–dentin–pulp fracture of the right maxillary canine tooth (104) in a cat

If diagnosed acutely, no radiographic abnormalities will be present. These lesions should be treated with endodontic therapy. The particular therapy chosen is dependent on the patient’s age and the duration of pulp exposure, and should be considered an emergency procedure in younger patients.^8,9 When pulpitis is not treated in a timely fashion, it becomes irreversible and extends apically to cause apical periodontitis. When apical periodontitis is present, treatment typically consists of root canal therapy. However, if severe root resorption is seen on a dental radiograph, extraction of the tooth is indicated.

Crown–root fracture

When a crown fracture extends below the gingival sulcus and into the root, the tooth is said to have a crown–root fracture (Figure 4). The apical extent of the fracture is typically not visible clinically and may not be visible on dental radiography. Computed tomography can be useful in visualizing vertical root fractures. However, surgical exploration may be necessary.

Figure 4.

(a) Crown–root fracture (with pulp involvement) of the left maxillary fourth premolar (208) in a cat with a concurrent alveolar fracture. Note that the primary cusp and the palatal root are missing. (b) Crown–root fracture (with pulp involvement) of the left mandibular canine tooth (304) in a cat

The endodontic consequences of, and thus treatment recommendations for, these injuries are similar to those described for enamel– dentin and enamel–dentin–pulp fractures. However, the root fracture component is a periodontal management concern. in order to have long-term success, the crown has to be restored in a way that does not compromise the health of the periodontium. Because the periodontium cannot heal to a restoration, the alveolar crestal bone has to be re-established apical to the fracture line. in some cases, this is too far apical for long-term periodontal health and extraction is the best option. Treatment of crown–root fractures may best be provided by a veterinarian with additional training and knowledge in dentistry.

Root fracture

Given that our patients rarely complain, root fractures (a fracture confined to the root of a tooth) are often incidental findings. oral examination may reveal an excessively mobile tooth in the absence of tooth resorption and periodontitis. A transverse radiolucent line through the tooth root will be seen radiologically (Figure 5).

Figure 5.

Radiograph of a root fracture in the cervical third of the right maxillary canine tooth (104) in a cat

Fractures located in the cervical third of the root will invariably be mobile and will require splinting. However, even with splinting, the prognosis for healing is guarded and extraction may be warranted. Fractures located in the middle third of the root may, or may not, be mobile. Splinting for 4–6 weeks provides the best chance of healing. Fractures located in the apical third of the root are typically non-mobile and may not require splinting. Radiographic monitoring to assess healing and pulpal health should be performed every 3–6 months for at least 1 year for all root fractures.

Concussion

A dental concussion injury results from blunt trauma which may or may not cause visible damage to the tooth. Concussions invariably lead to some degree of pulpitis, which may be reversible. often there is blue/pink/purple/ gray discoloration of the tooth (intrinsic staining) caused by hemorrhage within the pulp chamber (Figure 6). it is widely presumed that the great majority of intrinsically stained teeth are non-vital, and they will invariably become painful and necrotic. ¹⁰ Therefore, intrinsically stained teeth should be treated with endodontic therapy. Those cases that do not become intrinsically stained will likely recover without treatment.

Figure 6.

Left mandibular canine tooth (304) with intrinsic staining in a cat. Courtesy of Jan Bellows, Weston, FL, USA

Subluxation

Teeth are anchored within the jaws with the periodontal ligament and, as such, comprise the dentoalveolar joint. When a traumatic blow leads to a slight increase in tooth mobility, but normal tooth position is maintained, the tooth has likely sustained a subluxation. differential diagnoses include periodontitis, root fracture and alveolar fracture, which can be ruled out with a dental radiograph. dental subluxations typically resolve without treatment. However, if the mobility appears to be causing pain, an interdental splint can be applied for 7–14 days while the periodontal ligament heals.

Intrusive luxation

A luxation injury is one in which the tooth is displaced to some degree in or out of (but is still confined to) the alveolus. When a tooth is dislocated axially into the alveolus it is called an intrusive luxation. it will present clinically with gingival hemorrhage, a decreased crown height and mobility.

If the goal is to maintain the tooth, this injury should be considered an emergency. The recommended treatment is repositioning of the tooth (either orthodontically or surgically) and temporary splinting (2 weeks). Because the traumatic force will have been concentrated on the small surface area of the apical periodontal ligament (ie, the location of the vascular origin of the pulp), this injury typically leads to pulp necrosis. ¹¹ Therefore, endodontic therapy will be necessary. if the injury is chronic the best treatment option may be extraction, due to a poor prognosis.

Extrusive luxation

When a tooth is partially dislocated out of the alveolus in an axial direction the injury is referred to as an extrusive luxation. The tooth may appear elongated on visual inspection. Gingival hemorrhage, pain, mobility and a degree of root exposure are expected. The diagnosis can be confirmed by visualizing a widened periapical space on a dental radiograph.

The tooth can be replaced within the alveolus and splinted for 2 weeks. Because the neurovascular supply to the pulp is invariably severed, the pulp will become non-vital. in the immature permanent tooth, revascularization may occur and will not require endodontic treatment. However, in a mature tooth, root canal therapy is required. This can be performed either immediately after splinting or at the time of splint removal.

Lateral luxation

Luxation of a tooth in any direction other than axially is referred to as a lateral luxation. The canine tooth is most commonly affected and, if otherwise healthy, is luxated in a lateral direction. However, in the authors’ experience, luxated teeth in cats usually occur secondarily to periodontitis and will often be luxated in a rostral direction (Figure 7). Lateral luxations are typically accompanied by a fracture of the labial alveolar process. if both alveolar processes are fractured, the injury should be classified as an alveolar fracture (see page 921).

Figure 7.

Lateral luxation of the right maxillary canine tooth (104) in a cat. In this case, the tooth is suffering from severe periodontal disease and is being luxated rostrally secondary to contact with the right mandibular canine tooth (404). Courtesy of Matt Lemmons, Indianapolis, IN, USA

If the injury is not accompanied by severe periodontitis, the treatment is the same as for an extrusive luxation. The only additional step is to replace the fractured alveolar process. in addition, the splint should stay in place for 4 weeks. Endodontic therapy should be performed within 2 weeks of the splinting procedure. Teeth that are luxated secondarily to periodontal disease should be extracted.

Avulsion

An avulsion injury is an injury in which the tooth is completely displaced out of the alveolus. The tooth may remain attached to the gingiva. in the process of being avulsed, the neurovascular supply to the pulp and the periodontal ligament is completely severed and the entire root surface becomes exposed to the external environment.

If re-implanted in a timely fashion the injured tooth can be saved. However, if the root surface is exposed to the external environment for a prolonged period (>60 mins) prior to replacement within the alveolus, the remaining fibroblasts attached to the tooth root become desiccated. This leads to a severe and diffuse inflammatory response and eventual replacement resorption, making successful re-implantation impossible. ¹²

If the owner has witnessed the injury, he/she should be advised to re-implant the tooth and go immediately to a veterinarian with expertise in dentistry. if they cannot re-implant the tooth, the tooth should be stored in an appropriate medium (milk, saline, saliva, Hank’s balanced salt solution) until the tooth can be re-implanted. once the tooth has been re- implanted, it needs to be splinted for 2–4 weeks. in the case of a mature tooth, endodontic treatment is automatically delivered 7–10 days after re-implantation. in immature permanent teeth, the pulp has some potential to re-vascularize and may not need endodontic treatment. in the authors’ experience, avulsed teeth in cats usually occur secondarily to chronic periodontitis and should not be re- implanted if dental radiography reveals significant bone loss.

Alveolar fracture

An alveolar fracture is one that involves the entire alveolar process. A horizontal fracture line may run through the alveolus or apical to the alveolus. A vertical fracture line may be located in the septal bone between teeth or communicate with the periodontal ligament of a tooth. This injury typically involves multiple teeth that can be moved as a unit. However, the apex of one or more teeth may become entrapped on the bone and limit mobility. The pulp’s neurovascular supply is usually severed, although this is dependent on the distance the root apex travels away from the apical bone.

The fractured segment should be repositioned and splinted for 4–6 weeks with a rigid resin/acrylic splint. The teeth involved may need endodontic treatment depending on whether the neurovascular supply was severed or not. Endodontic health should be assessed with radiographs every 6 months for at least 1–2 years. The long-term prognosis is excellent in young animals and good to very good in adults, if treated in a timely manner.

Maxillofacial trauma

Maxillary and temporomandibular joint injury

Maxillary injury often presents with subtle signs, making it more challenging than other maxillofacial injuries to diagnose. Maxillary injuries may be amenable to conservative management (pain medication and soft food) to achieve reasonable healing. Signs of maxillary trauma can include malocclusion of particular teeth or an entire arcade, traumatic oronasal fistula formation, epistaxis and swelling of the maxillary or nasal region (Figure 10). Any cat sustaining head trauma should undergo a close ophthalmic evaluation, and patients presenting with Horner’s syndrome should be assessed for possible craniomaxillofacial trauma (Figure 11). Patients suffering documented maxillary injuries should also be evaluated for changes in ocular position and movement (indicative of traumatic injury involving the extraocular muscles or insertion locations on the orbital rim).

Figure 10.

Oral evaluation of cats with epistaxis may reveal a wide variety of findings including soft tissue lacerations, malocclusion and dentoalveolar injury. The presence of epistaxis and malocclusion of the maxillary arcade should increase suspicion that multiple craniomaxillofacial fractures exist. Note the crown fracture on the left mandibular canine tooth (304)

Figure 11.

Cats demonstrating an inability to open the mouth, signs of epistaxis or discrepancy in pupil size should be closely assessed with ophthalmic and neurologic evaluation for head trauma. This patient demonstrates all of these clinical signs

Figure 8.

Diagnostic evaluation with CT provides easier documentation of multiple injuries affecting the craniomaxillofacial region. Fractures involving the skull (#), pterygoid process (*), right mandibular ramus (^) and zygomatic arch ($) are all depicted in this image

Figure 9.

This 8-week-old patient suffered a condylar neck fracture that resulted in exuberant bone healing and ankylosis (^) of the left temporomandibular joint (TMJ). The right TMJ space is slightly wide (subluxated) (*) due to deviation of the mandibles to the left

The combination of the predilection of young patients for sustaining injury and their robust healing potential makes complete diagnostic imaging of the entire craniomax- illofacial region necessary to identify possible long-term effects from injury. Younger patients with condylar neck or intra-articular fractures may be more predisposed to developing true ankylosis of the TMJ. Treatment for these patients is centered on early diagnosis and condylectomy (removing the affected segment while maintaining attachment of the muscles of mastication) or caudal man- dibulectomy, with the primary goal of returning function and range of motion. Horner’s syndrome has been reported following treatment of TMJ injury in cats due to trauma from the coronoid process of the ramus on the periorbita and postganglionic fibers. ¹⁶

Symphyseal separation

Symphyseal separation is commonly reported in cats and may be associated with motor vehicle accidents5 and falls.3 The feline mandibular symphysis is not fused and the fibrocartilaginous connection defines it as a joint. inherent laxity exists in the symphysis and discriminating between pathologic instability and normal laxity can be difficult. in most instances if the sublingual mucosa is intact, then the laxity is likely physiologic.

Repair of symphyseal separation should include repair of lacerated mucosa and stabilization of the right and left mandibles. Symphyseal wiring with bilateral mandibular cerclage, or intermandibular stabilization with a resin/acrylic splint, are common approaches for these patients.^17,18 if the appropriate materials are available for non- invasive stabilization using a resin/acrylic, additional benefits to this technique include lack of a ventral skin incision required for mandibular cerclage wire placement, decreased risk of infection and lack of disruption of the fracture hematoma. A modified symphyseal separation repair technique has been proposed whereby mandibular cerclage wire is placed with wire twists distal and buccal to the canine tooth rather than being submerged under the ventral skin or exiting through a ventral skin incision. ¹⁸ By placing wire twists caudal to the canine tooth, removal of the fixation device is simplified – involving cutting the wire and removing it entirely through an intraoral approach (Figure 12).

Figure 12.

(a) The modified symphyseal wiring technique orients the wire twists within the mouth and lateral to the right mandibular canine tooth (404). Maintaining wire twists (protected with a bleb of composite) within the mouth facilitates easy removal by cutting the wire and removing the entire fixation device through the oral cavity. (b) Radiograph depicting mandibular symphyseal wiring at the time of injury, with wire twists distal to the right mandibular canine tooth (404) of the patient. (c) Eight-week postoperative radiograph demonstrating healing in a patient managed with symphyseal wiring

Lateralization of the coronoid process

Cats presenting with an inability to close the mouth should be closely evaluated for TMJ luxation or lateralization of the coronoid process. Palpation of the face and zygomatic region will help determine whether displacement of the coronoid process has occurred. Lateralization of the coronoid process has been described in several reports.^19,20 Although the specific etiology may be unclear, a variety of anatomic variations have been hypothesized to contribute to the condition. The list of proposed predisposing factors includes excessive symphyseal laxity, decreased space between the zygomatic arch and coronoid process, a hypoplastic condylar process, hypoplastic retroarticular process or hypoplastic mandibular fossa. ²⁰ Unlike TMJ luxation, lateralization of the coronoid process results in the cat being unable to close the mouth without associated abnormal tooth-on- tooth contact. ²⁰

Immediate correction of this condition can be achieved with heavy sedation or brief general anesthesia, enabling the mouth to be opened wide and so permit the coronoid process to swing below the ventral border of the zygomatic arch and become reduced to its normal position.

A long duration of the lateralized state, or frequent lateralization of the coronoid process, may result in stretching of the joint capsule and result in increased risk of recurrence. Recommended treatments for this condition have included symphysiotomy, coronoidectomy and partial zygomectomy. ²⁰ The authors have reported success with partial coronoidectomy alone. ¹⁹ At the time of definitive surgery, palpation should be performed under general anesthesia to attempt to lateralize both sides, with bilateral treatment performed if necessary (Figure 13).

Figure 13.

(a) Patients presenting with lateralization of the coronoid process demonstrate an inability to close the mouth (passively or actively) and ptyalism resulting from inability to manage saliva. (b) CT image depicting the lateralization of the left coronoid process (*) to the zygomatic arch (#). (c) Following coronoidectomy, CT of the open-mouth position demonstrates that the coronoid process is now shortened (*) and lacks the potential for becoming laterally positioned to the zygomatic arch

Craniomaxillofacial fracture management

Invasive fracture repair techniques

A variety of invasive forms of fracture management have been reported in cats including the use of titanium miniplates, ²¹ external skeletal fixators ²² and interfragmentary wiring. The last may provide the most flexibility of the invasive repair techniques; however, given limited bone height and, depending on the orientation of the fracture, it may be difficult to orient the interfragmentary wires perpendicular to the fracture line without damaging tooth structure or the inferior alveolar artery, vein and nerve (Figure 14).

Figure 14.

Forms of fracture fixation such as external fixators and orthopedic plates and screws have an inherent risk of damaging tooth structure if pilot holes are not placed carefully. The pilot hole associated with the external fixation used for fracture repair in this cat risks damage to structures within the mandibular canal as well as the blood supply to this left mandibular first molar (309). Courtesy of Don Beebe, Englewood, CO, USA

Maxillary split injuries result in superimposed shelves of the hard palate and subsequent narrowing and possible shifting of the maxillary arcade. Surgical creation of a symphyseal separation has been described as a treatment option for the subsequent malocclusion of the mandibular teeth with the hard palate. ²³ While this approach to surgical correction may have alleviated traumatic occlusion, it is unknown what the short- and long- term impact is on the articular surfaces of the TMJ. Manipulation of the mandible resulting in TMJ destabilization ²⁴ has been shown to cause articular surface changes in weightbearing and non-weightbearing mandibles of the dog; similar changes may be seen in cats. Although the clinical effects of these histologic changes to the articular cartilage and subchondral bone are unknown, every attempt should be made to restore the traumatized patient back to a normal occlusal and anatomic positioning. Many cats will heal uneventfully from repair of the soft tissues associated with a midline maxillary fracture and subsequent selective dental treatment for any traumatically contacting teeth (Figure 15).

Figure 15.

(a) A patient suffering multiple maxillofacial injuries demonstrates a split hard palate and left maxillary alveolar fracture. (b) The maxillary alveolar fracture was reduced using interfragmentary wiring (24 G) followed by placement of an intraoral composite splint. (c) Multiple maxillofacial injuries require creative application of a variety of repair techniques. In this instance, primary closure of the soft tissue lacerations; interfragmentary wiring and composite splinting of the left maxillary fracture; and intraoral composite splinting for stabilization of an incisive fracture andmandibular symphyseal separation

The mandibular body has been reported as being the second most common location for mandibular fractures.5 inevitably some fractures in this area will involve tooth roots in the fracture line. Hemisection with vital pulpotomy or hemisection with root canal therapy may afford preservation of the uninvolved segment of the tooth (Figure 16). Benefits of maintaining the tooth root in a fracture line include increased stabilization of the fracture fragment surfaces and incorporation of the additional crown structure in non-invasive fracture repair techniques. However, if the tooth root involved in the fracture line demonstrates signs of periodontal or endodontic disease, extraction or hemisection should be considered to help reduce bacterial contamination and complications of fracture healing.

Figure 16.

Interfragmentary wires should be placed perpendicular to the fracture line to prevent telescoping of the fracture fragments when compression is created. When limited bone exists, interfragmentary wires can share a common pilot hole and the relationship of each wire segment should result in a perpendicular force reducing the fragments. The distal root of the left mandibular first molar (309) was in the fracture line and has been resected in this patient

Invasive jaw fracture repair techniques have been shown to damage cementum and dentin in dogs when screws are placed peripheral to the tooth structure.^25,26 Capacity for cementum regeneration and repair has been observed histologically in dogs; more information is necessary to determine if a similar type of recovery is plausible in cats. With the large tooth root size, presence of neurovascular structure in the mandibular canal and limited available bone stock in the mandible in cats, alternative methods of fixation should be considered whenever possible.

Non-invasive fracture repair techniques

Use of non-invasive repair techniques including intraoral composite splinting should be strongly considered whenever fracture stabilization is necessary. Chances of spontaneous dislodgement of the device can be countered with additional bonding of the composite to the tooth structure, ²⁷ or incorporation of mandibular cerclage wires into the device or a K-wire arch bar within the composite. interdental wiring may be considered for feline oral fracture repair; however, this may be exceptionally challenging due to the small size and limited number of teeth present. The combination of interdental wire and composite in splinting mandibular body fractures has been experimentally shown in dogs to be stronger than either form of fixation used alone. ²⁸

Restoration of the alignment of the maxillary and mandibular canine teeth and application of maxillomandibular fixation in a partial open mouth position has been demonstrated clinically to produce successful healing ²⁹ and is reasonably accepted by feline patients (Figure 17). Use of techniques such as this or composite splint application to the mandible or maxilla provides the benefits of a less invasive repair, no disruption of the fracture hematoma and reduced risk of damaging the blood supply to nearby teeth.

Figure 17.

Maxillomandibular fixation can serve as a successful form of fixation on the premise that alignment of the maxillary and mandibular canine teeth will realign mandibular fracture fragments. Patients should not remain in maxillomandibular fixation for longer than 3–5 weeks or they may risk false (functional) ankylosis. Canine tooth cusp tips should be approximated, but not overlap greatly, to provide appropriate maxillomandibular approximation and to facilitate composite removal while minimizing iatrogenic tooth damage. In addition to a mandibular body fracture, maxillomandibular fixation in this patient is also being used to manage a symphyseal separation (composite spanning mandibular canine teeth and incisors)

When applying composite to realign the maxillary and mandibular canine teeth, teeth must be ultrasonically scaled and acid etched to facilitate micromechanical retention of composite. it has been shown that the bond strength between the tooth structure and composite can be greatly increased with the addition of a bonding agent. ²⁷ While increased bond strength may be desirable to reduce the likelihood of spontaneous separation between the tooth surface and composite, it has been reported to increase the time required for composite removal and increases the rate of iatrogenic tooth injury during removal. ²⁶ There is a lack of information available regarding the relationship between the extent of the fixed open-mouth position and ability to swallow. Generally, maxillomandibular fixation with composite involves positioning the canine teeth cusp tips in a slight overlap, enabling the patient to access food and water while ensuring alignment of the jaws.

Key Points

• The quantity and severity of traumatic dentoalveolar injuries tend to increase in p with concurrent maxillofacial fractures.

• Traumatic dentoalveolar injuries are also often found in otherwise healthy cats.

• The goal is early identification and treatment of dentoalveolar and maxillofacial injuries to produce a rapid return to a functional, pain- and inflammation-free occlusion.

• Non-invasive fracture repair techniques should be considered whenever possible to avoid iatrogenic injury to dental or neurovascular structures.