Either swelling in the pulp or the exposure of the dentine (Wetherell 144) may cause tooth pain. In the present case, my friend’s pain may be because of dental caries, fractured fillings, or even a cracked cusp. This leads to the dentine root surface to be exposed which makes him experience pain when either a hot, cold or sweet stimuli are applied (Wetherell 145). Nervous innervations of the lower teeth may be caused by the Trigeminal Nerve (TN) which provides the innervations against touch, pressure, nociception and thermal sense. TN is the largest of the cranial nerves, and it consists of sensory neurons and it emanates from the brain before entering the trigeminal ganglion (TGG). This is followed by an extensive series of nerve divisions including the mandibular nerve (Piagkou et al 71). The mandibular nerve (MN) is a division of the TGG that further branches into the alveolar nerve. The alveolar nerve branches into the mylohoid nerve, alveolar artery, and finally the incisive nerve that provides sensory innervations to the premolar teeth (Rodella et al 326). The loss of feeling in the tongue, dry mouth and change in taste is caused by alveolar nerve block due to the anesthetic effect (Rodella et al, 327). This may also be due to chemical damage to the lingual nerve because of direct injection of a neurotoxic local anesthetic such as articaine, procaine, lidocaine, tetracaine and bupivacaine (Klasser 458). The loss of taste is caused by the anesthetic effect caused by injuries to the lingual nerve during the dental work. The lingual nerve is anesthetized during an alveolar nerve block (Rodella et al, 328). The lingual nerve transfers gustatory fibers responsible for taste sensation to the anterior part of the tongue (Piagkou et al 76). Saliva has also been linked by research to taste response where a low flow affects taste sensation (Klasser 459). The motor function of the tongue is not interfered with because the mandibular nerve has an additional motor component that runs separate to the facial component (Piagkou et al 74). This provides sensory communication between the myoholid nerve and the lingual nerve that controls motor functions of the tongue (Rodella et al 329).Works CitedKlasser, Garry D, Robert Utsman, and Joel Epstein. Taste Change Associated with a Dental Procedure: Case Report and Review of the Literature. Journal of the Canadian Dental Association 74.5 (2008): 455-461. Print.Piagkou, Maria, Theano Demesticha, Giannoulis Piagkos, Panayiotis Skandalakis, and Elizabeth Johnson. The Mandibular Nerve: The Anatomy of Nerve Injury and Entrapment. InTech, 23 May, 2012. Web. 28 November 2014 lt. http://cdn.intechopen.com/pdfs- wm/37175.pdfgt. Rodella, L.F, Buffoli, B., Labanca, M, and Rezzani, R. A review of the mandibular and maxillary nerve supplies and their clinical relevance. Archives of Oral Biology 57, (2012): 323-334. Print.Wetherell, John, Lindsay Richards, Paul Sambrook, and Grant Townsend. Management of acute dental pain: a practical approach for primary health care providers. Australian Prescriber 24.6 (2001): 144-148. Print.