North American pet ferrets with fractured teeth = 30.0%. Feral New Zealand ferrets with fractured teeth = 4.6%. Wild polecats (all combined) with fractured teeth = 0.0%. 93.8% of all animals with fractured teeth were pet ferrets. There are several ways you can identify and count a fractured tooth depending on the degree and position of fracture, if the fracture extends through the tooth, if it is a slab fracture, or if it is a crack, chip, or spall. Most fractures in ferret teeth do not extend entirely through the tooth, but are instead are cracks into or through the enamel, chipped tips of canines and premolars, and various degrees of spalled enamel. Sometimes a fractured tooth is the result of extreme dental wear (attrition) which has weakened the tooth until it fractures, usually between the roots. If the tooth has been shattered and the damage was not caused by diet-mediated wear, it nearly always was a canine tooth. A few canine teeth had large slab fractures, probably the result of a high-energy impact, such as from a fall or accidental kick, or perhaps from cage biting. In the majority of carnivores, slab fractures are most commonly seen in the carnassials, but in mustelids they generally involve the canines. Slab fractures occur when a portion of the crown breaks off the tooth, removing a large portion of enamel and exposing the dentine; occasionally the pulp chamber is involved. Sometimes the fragment extends under the gums, involving the roots. It is called a slab fracture because the fragment looks like a slab of tooth. In this study the pulp chamber was never exposed in ferret canines with slab fractures, but a large area in the front of the tooth was damaged. Interestingly, not a single slab fracture to a cheek tooth was seen in the entire study, including bone-eating polecats and feral New Zealand ferrets. This is important because some vets suggest the type of slab fractures seen in carnassials from dogs that chew bones will occur to ferrets if also allowed to chew bone; these data suggest ferrets are not dogs. This finding doesn t exclude the possibility that a slab fracture will happen to a ferret s carnassial, it simply means it is a very rare event and wasn t sampled. I feel a slab fracture can occur to a ferret s carnassial under the right circumstances, especially one that displays extreme wear. There is a point where the dentine wears faster than the surrounding enamel and shallow dish-like shape forms in the crown. In these heavily worn teeth, pressure on the enamel portions could potentially cause slab fractures from ANY reason. Generally speaking, one of the reasons dogs frequently suffer from slab fractures in their carnassials and ferrets generally don t is situated in the biomechanics of their jaw attachments. Dog jaws have a comparatively short temporal-mandibular joint (TMJ) seated in a short groove, but the TMJ in ferrets is comparatively quite large, and is seated in a deep, long groove that essentially locks it into place. When a dog bites a hard object with a lot of force, the lower jaw can slightly dislocate and slip to one side, producing lateral forces that can chip off a slab of tooth in a fashion similar to chipping off flakes of obsidian to make an arrowhead. Tooth enamel and dentine, like bone, are bioceramics; they are governed by the same rules of physics that apply to fracturing glass and stone, and they break in exactly the same manner. In contrast, ferret jaws are locked into place and the force required to cause the jaw to slip laterally is generally greater than is needed to fracture the TMJ and dislocate the jaw (ferret jaw dislocations are very rare compared to other carnivores, and generally are the result of some type of damage to the TMJ). The point is that a slab fracture requires lateral force applied to the top AND side of the tooth exactly the same type of lateral force applied to the edge of a stone to remove a flake, or slab. Because a ferret s jaw is constructed to prevent that sideways force, it is rare for their carnassials to break in that manner. There were a couple of cases in this study where one of the points of a carnassial was spalled (the enamel flaked off, but little damage to the underlying dentine), but in those instances other teeth displayed fractures that suggested the damage was due to a fall or other trauma. Pet ferrets have a tooth fracture rate of 30.0%, significantly greater than rates seen in feral New Zealand ferrets, wild polecats, or even the averaged rate for mammals in general. In one four-year-long British study of 350 ferrets, the fracture rate was 0.9%. Feral New Zealand ferrets had a tooth fracture rate of 4.6%, which is roughly the average from several studies of small carnivores (fracture rates varied from 2% to 12%), but the rate may have been artificially inflated by the methods used for trapping and killing. A British study of otters had a 19% rate of both fractured and missing teeth (the two values were lumped together because the researchers were collecting data from necropsies, not from cleaned skeletons), with a carnassial fracture rate of 2.5%. Wild felids were found in a study of skeletons to have a dental fracture rate of 15% to 24% and 29% of wolves in the same study had fractured teeth. For quite a long time it was thought that large animals that ate large prey had higher tooth breakage rates than small animals that ate smaller prey. The idea was that the struggle with larger prey opened the carnivore to a greater risk of injury. This idea has been mostly falsified in recent years when it was realized the risk of having a broken tooth was better correlated to age. This hypothesis suggests the older the animal, the more accumulated damage to the teeth hence the higher fracture rates. In this study, dental fractures were correlated with age, meaning that the longer a ferret lives, the more dental problems are seen. If injury is accumulative, as is currently the accepted paradigm, then sidetracking damage will reduce the long-term destruction of teeth. This is exactly what is done when you initiate a daily tooth-brushing regime with yearly tooth cleaning. [Posted in FML issue 4520]