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INTRODUCTION

Dental anesthesia techniques are used by Emergency Physicians for a variety of intraoral and extraoral conditions. This includes dental caries, jaw fractures, dry sockets, intraoral hemorrhage, laceration repair, and tooth fractures. These techniques are simple to learn, easy to perform, and provide temporary pain relief for the patient. The Emergency Physician can provide pain-free intraoral manipulations, extraoral manipulations, facial manipulations, and simple pain control until the patient receives definitive evaluation and treatment by a Dentist or Oral Surgeon. The fundamental principles of dental anesthesia and anatomy will be discussed so that the Emergency Physician will feel knowledgeable and comfortable performing dental anesthetic techniques.

ANATOMY AND PATHOPHYSIOLOGY

An understanding of the anatomy of the fifth cranial nerve is essential to performing dental nerve blocks (Figure 209-1).1-3 The fifth cranial nerve is also referred to as CN V or the trigeminal nerve. It is the largest cranial nerve. It is a mixed cranial nerve containing primarily sensory fibers to the skin of the face and scalp, the nasal cavity, and the oral cavity. The motor fibers innervate the muscles of mastication.

FIGURE 209-1.

The anatomy of the trigeminal nerve.

The trigeminal nerve originates in the brainstem as a small motor root and a large sensory root. These roots fuse as they leave the brainstem. The trigeminal nerve travels forward into the middle cranial fossa where it expands into the large and crescent-shaped trigeminal ganglion. The trigeminal ganglion divides to give rise to the three divisions of the trigeminal nerve: the ophthalmic nerve (V1), the maxillary nerve (V2), and the mandibular nerve (V3) (Figure 209-1). Each of these nerves leaves the middle cranial fossa through its own foramen.

OPHTHALMIC NERVE

The ophthalmic nerve is the smallest branch of the trigeminal nerve. It travels forward in the lateral wall of the cavernous sinus and enters the orbit via the superior orbital fissure. It provides sensory innervation to the forehead, scalp, upper eyelid, cornea, nasal cavity, sinuses, and the orbit. This nerve is not discussed further because it does not innervate any oral or dental structures.

MAXILLARY NERVE

The maxillary nerve is purely sensory. It travels forward in the lateral wall of the cavernous sinus and exits the cranial vault via the foramen rotundum into the pterygopalatine fossa. It then enters the orbit through the inferior orbital fissure to continue on as the infraorbital nerve and emerge on the face. The infraorbital nerve terminates as a sensory nerve to the lower eyelid, upper cheek, nose, and upper lip. The infraorbital nerve gives off the anterior superior alveolar nerves prior to its termination. These nerves supply the maxillary sinus, the maxillary incisors, the maxillary canine teeth, and the ...

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