This chapter includes bruxism, fracture of teeth, tooth ankylosis, eosinophilic ulceration, mucocele, ranula, maxillary arthrolithiasis, rhinolithiasis, X-ray radiation, osteoradionecrosis, laser radiation, electrical burns, thermal burns, cervicofacial emphysema, pneumoparotid, anesthetic necrosis, human bite, poisoning, cancer chemotherapeutic agents.