Indications and Clinical Considerations
The buccal fold injection technique is useful in the diagnosis and treatment of pain involving the incisors or canine teeth of the upper jaw. This technique can provide much-needed emergency relief of dental pain while the patient is waiting for definitive dental treatment. It can also serve as a useful diagnostic maneuver when the clinician is trying to localize the nidus of pain that the patient perceives as dental in origin.
Dental pain is the result of irritation or inflammation of the nerves of the pulp and/or root of the tooth. Common causes of irritation or inflammation responsible for dental pain include infection, decay with resultant nerve exposure, gingival disease, plaque at or below the gum line, bruxism, injury, tumor, and tooth extractions ( Figure 4-1 ). Less common causes include chemotherapy-induced odontalgia and barodontalgia. Pain involving the incisors or canine teeth may also be referred from other anatomic areas. Such referred pain may be indicative of temporomandibular joint dysfunction, sinus disease, abnormalities of the trigeminal nerve and its branches, and coronary artery stenosis.
Dental pain may range from a dull ache to severe unremitting pain. Its onset may be insidious or acute. Dental pain is often worse when the affected tooth or teeth are exposed to hot or cold temperatures and when direct pressure is applied to the tooth or teeth when chewing. Tapping on the affected tooth or teeth may elicit an acute exacerbation of the pain. If significant inflammation or infection is present, rubor and color may be present as well as swelling. Gingival bleeding or purulent drainage may also be present. It should be remembered that on occasion a severely compromised tooth that is causing a patient significant pain may appear completely normal.
Clinically Relevant Anatomy
The incisor and canine and surrounding periosteum and buccal and gingival tissue are innervated by the superior alveolar nerve, which is a branch of the inferior alveolar nerve just before it exits from the infraorbital canal below the orbit ( Figure 4-2 ). Fibers of the ipsilateral superior alveolar nerve may cross the midline and may anastomose with fibers of the contralateral nerve, although medial spread of injected local anesthetics may be limited by the attachments of the labial frenulum at the midline. The periosteum and bone that surround and support the root of the tooth are relatively thin and readily allow diffusion of local anesthetics injected in this region ( Figure 4-3 ).
