Management of Pain and Anxiety
As clinicians, dental hygienists must be able to manage the client’s pain and anxiety. This requires mastery of head and neck anatomy, physiology, pharmacology, medical emergencies, and clinical technique. Local anesthetic agent administration is within the legal scope of dental hygiene practice in most legal jurisdictions in the United States. This chapter reviews four methods to relieve and manage pain and anxiety: (1) local anesthesia, (2) topical anesthesia, (3) computer-controlled local anesthesia, and (4) nitrous oxide–oxygen conscious sedation.
FIGURE 18-2 Components of a hypodermic needle. A, Shaft or shank, the working end of the needle. B, Bevel, or angulation, of the tip. C, Lumen, the hollow interior of the shaft. D, The hub holds the shaft and is threaded onto the adaptor of the syringe. E, The syringe end enters the anesthetic cartridge. F, The protective shield sleeve (colored end) covers the needle shaft. G, The protective shield guard (clear or white) covers the syringe end of the needle. H, The security seal holds the protective shield sleeve and guard together until the hub is assembled and attached to the syringe.
FIGURE 18-4 A, Assembled breech-loading, metallic, cartridge-type syringe. B, Disassembled local anesthetic syringe. (Modified from Malamed SF: Handbook of local anesthesia, ed 5, St Louis, 2004, Mosby.)
A Definition—the amount of drug capable of causing adverse systemic reactions in normal persons; adverse reactions occur when the rate of drug absorbed is greater than the rate of biotransformation, the body’s ability to metabolize the drug
5. Cetacaine—a combination of benzocaine, butamben, and tetracaine hydrochloride—is an ester topical indicated in adults who require pre-injection, deep scaling, and suture removal anesthesia (available in spray, liquid, or gel form)
D Topical agents have indications and contraindications; can interact with other medications; clinicians must always assess for potential allergies, side effects, and adverse effects and take appropriate precautions
1. Percentage of the anesthetic drug is the number of grams (g) of drug per 100 milliliters (mL) of solution (e.g., 2 g anesthetic drug/100 mL solution = 2% anesthetic solution). To find the number of milligrams of drug in 1 milliliter of solution, change the grams of drug to milligrams (mg) by multiplying by 1000 (e.g., 2 g drug/100 mL solution × 1000 mg/1 = 2000 mg/100 mL = 20 mg drug/1 mL solution). This calculation determines that 20 mg of anesthetic drug (e.g., lidocaine) are in each milliliter of this anesthetic solution
2. To calculate the number of milligrams of anesthetic drug (e.g., lidocaine) that is administered, multiply the number of milligrams per milliliter of the drug by the number of milliliters of solution administered
3. To compute the MRD of an anesthetic drug in cartridges, divide the MRD in milliliters by the number of milliliters in 1 cartridge (1.8). The MRD of lidocaine 2% is 15 milliliters (15 mL/1.8 mL = 8.3 cartridges)
3. All vasoconstrictors can be produced synthetically; two naturally occurring vasoconstrictors, epinephrine and norepinephrine, are produced in the adrenal medulla and the sympathetic postganglionic nerve fibers
C Function—hold the local anesthetic agent in the target site of analgesia by producing vasoconstriction; if absent from a local anesthetic agent, vasodilation will occur; the results of vasoconstriction are:
3. Each type of vasoconstrictor possesses varying degrees of response of both α- and β-activity (see Table 18-2); although epinephrine exhibits the most β-activity, to achieve the same amount of vasoconstriction as epinephrine, the concentration of all other vasoconstrictors must be increased
E Biotransformation—metabolism of vasoconstrictors occurs in the bloodstream; the enzyme responsible for biotransformation is monoamine oxidase (MAO); persons taking MAO inhibitors have a decreased ability to metabolize vasoconstrictors