Editing Canidae (section)

===Dentition===

[[Dentition]] relates to the arrangement of teeth in the mouth, with the [[Dentition#Dental formula|dental notation]] for the upper-jaw teeth using the upper-case letters I to denote [[incisors]], C for [[Canine tooth|canines]], P for [[premolars]], and M for [[molars]], and the lower-case letters i, c, p and m to denote the [[Mandible|mandible teeth]]. Teeth are numbered using one side of the mouth and from the front of the mouth to the back. In [[carnivores]], the upper premolar P4 and the lower molar m1 form the [[carnassials]] that are used together in a scissor-like action to shear the muscle and tendon of prey.{{sfn|Wang|Tedford|2008|pp=74}}

Canids use their premolars for cutting and crushing except for the upper fourth premolar P4 (the upper carnassial) that is only used for cutting. They use their molars for grinding except for the lower first molar m1 (the lower carnassial) that has evolved for both cutting and grinding depending on the canid's dietary adaptation. On the lower carnassial, the [[trigonid]] is used for slicing and the [[talonid]] is used for grinding. The ratio between the trigonid and the talonid indicates a carnivore's dietary habits, with a larger trigonid indicating a [[hypercarnivore]] and a larger talonid indicating a more [[Omnivore|omnivorous]] diet.<ref name=sansalone2015/><ref name=cherin2013/> Because of its low variability, the length of the lower carnassial is used to provide an estimate of a carnivore's body size.<ref name=sansalone2015/>

A study of the estimated bite force at the canine teeth of a large sample of living and fossil mammalian predators, when adjusted for their body mass, found that for [[placental mammals]] the bite force at the canines <!-- (in [[Newton (unit)|Newtons]]/kilogram of body weight) --> was greatest in the extinct dire wolf (163), followed among the modern canids by the four hypercarnivores that often prey on animals larger than themselves: the African wild dog (142), the gray wolf (136), the [[dhole]] (112), and the [[dingo]] (108). The bite force at the carnassials showed a similar trend to the canines. A predator's largest prey size is strongly influenced by its biomechanical limits.<ref name=wroe2005/>

Most canids have 42 [[teeth]], with a [[dentition|dental formula]] of: {{DentalFormula|upper=3.1.4.2|lower=3.1.4.3}}. The bush dog has only one upper molar with two below, the dhole has two above and two below. and the [[bat-eared fox]] has three or four upper molars and four lower ones.<ref name=Mivart/> The molar teeth are strong in most species, allowing the animals to crack open bone to reach the [[bone marrow|marrow]]. The deciduous, or baby teeth, formula in canids is {{DentalFormula|upper=3.1.3|lower=3.1.3}}, molars being completely absent.<ref name=Mivart/>