Test malocclusion – improper alignment of upper and lower jaw or teeth mandible – lower jaw mandibular canal – space within the mandible which holds the blood vessels and nerves for the lower jaw and teeth mastication – chewing, generally of food maxilla – upper jaw maxillary sinus – open cavity inside the maxilla molar – rearmost teeth, cusped, used for grinding food mouthguard – appliance used to protect the mouth and teeth during rigorous activity, such as sports