Pain control is a critical element in successful dentistry. Many anesthetic agents are available to help clinicians provide comfortable patient care. Oral health professionals are charged with choosing the most appropriate anesthetic agent for patients, considering medical history concerns and treatment needs. And you, as a dental sales rep, can benefit by sharing valuable anesthetic product knowledge, including formulations and considerations, with your clients — and maybe even to seek out new customers.
Vasoconstrictors are added to anesthetics to increase the depth and duration of anesthesia, and reduce the risk of toxicity.1 Vasoconstrictors have absolute and relative contraindications. An absolute contraindication is a situation in which vasoconstrictors should not be administered under any circumstances, such as a patient with uncontrolled hyperthyroidism.2 For patients with a relative contraindication, the risk vs benefit ratio should carefully be considered. For example, when using a vasoconstrictor with a patient taking tricyclic antidepressants, the vasoconstrictor should be limited to the lower dosage limit of 0.04 mg.2 Lidocaine 2% is available with 1:50,000 epinephrine. This concentration of epinephrine is indicated when strong hemostasis is needed. Administering infiltrations in the treatment area will control bleeding in the field. An epinephrine concentration of 1:100,000 will provide the same depth and duration of anesthesia, while administering half as much epinephrine. The epinephrine concentration of 1:100,000 should be the most concentrated amount administered for pain control in most dental procedures.1 Prilocaine and articaine are available in formulations with epinephrine 1:200,000. This concentration provides similar depth and duration of pain control as 1:100,000, using half as much epinephrine. These formulations can be appropriate options for patients with relative contraindications for vasoconstrictor use.
Amides and esters are the main categories of anesthetics used in dentistry. All injectable drugs are amides, and many topical drugs are esters. While allergies to local anesthetics are rare, most are related to esters. When patients report a history of allergic response, all anesthetics should be avoided until appropriate allergy testing has been completed.
The use of prilocaine in patients with a history of methemoglobinemia or other medical conditions characterized by reduced oxygen-carrying capacity raises the risk of methemoglobinemia, therefore it is contraindicated.3 Large doses of benzocaine may also raise the risk of methemoglobinemia.3
Research demonstrates that 4% anesthetic solutions (articaine and prilocaine) have an increased risk of post-operative paresthesia, primarily with mandibular nerve blocks.4–8 The risk of a post-operative paresthesia, however, is still very low.5,6 Research also shows that articaine provides more reliable anesthesia than other agents when administered via infiltration.3,4,9,10 However, articaine has not demonstrated significant advantages over lidocaine when administered via mandibular nerve block.8
INJECTABLE ANESTHETIC FORMULATIONS
Injectable dental local anesthetic agents provide a range of anesthetic durations. Selection should be made with the individual patient’s procedure and medical history in mind. All injectable solutions are contraindicated in patients with known allergies to amide anesthetics or any component of the formulation. Table 1 provides formulations for many popular injectable anesthetic solutions.
Topical anesthetics only provide soft tissue anesthesia, and the depth and duration of anesthesia are less than are provided by injectable anesthetics. Topical anesthetics may contain a variety of drugs including benzocaine, butamben, dyclonine hydrochloride, lidocaine, prilocaine, and tetracaine.
An intrapocket topical anesthetic intended specifically for use in periodontal therapy procedures combines 2.5% lidocaine and 2.5% prilocaine. This product undergoes thermosetting at body temperature. In other words, it is a liquid in the cartridge and sets into a gel in the sulcus, which aids in retention. This combination is applied into the sulcus using a blunt-tipped syringe and can provide a suitable substitute for injectable anesthetics during dental hygiene procedures. However, pulpal anesthesia should not be expected.11 This drug combination and application method have demonstrated efficacy in controlling pain during scaling and root planing and periodontal probing.12,13 In studies comparing this topical to injected anesthetics, most patients preferred the topical option, despite experiencing more pain during periodontal therapy.14,15 The onset of this drug is 1 minute and its duration is approximately 20 minutes. The maximum recommended dose is five cartridges per appointment. As the combination includes prilocaine, this combination is contraindicated in patients at risk for methemoglobinemia.
The combination of 14% benzocaine, 2% tetracaine, and 2% butamben is a topical anesthetic indicated for use on all mucous membranes except the eyes. It has a long history of use in dentistry and medicine.16,17 This combination of anesthetics provides a short onset of action with a fairly long duration of anesthesia16 and has been recommended by prominent dental professionals.18,19 However, there are no studies that specifically address its efficacy in pain control during scaling and root planing or other dental hygiene procedures.
While this topical combination is available in gel and spray forms, the liquid formulation can be applied subgingivally. When used subgingivally, it may be able to replace injectable anesthetics for dental hygiene procedures.11 The liquid is introduced into the gingival sulcus using a blunt-tipped syringe. The recommended dose is 200 mg (0.2 mL of the liquid formulation). Each 200 mg contains 28 mg of benzocaine, 4 mg of butamben, and 4 mg of tetracaine. No appropriate dose has been determined for children. Clinicians should consult the package insert for complete dosing guidelines.
The onset of this benzocaine/tetracaine/butamben combination is approximately 30 seconds and it lasts 30 to 45 minutes.11 Dosing in excess of 400 mg (0.4 mL of liquid) is contraindicated. Benzocaine, tetracaine, and butamben are all ester anesthetics, which are contraindicated in patients with allergies to esters and those at risk for methemoglobinemia.
UNDERSTANDING MAXIMUM RECOMMENDED DOSES
Several important pharmacological principles should be considered prior to selecting an anesthetic agent, including onset time, duration of anesthesia, contraindications, potential adverse effects, and maximum recommended dose (MRD). An important note regarding MRD: the United States Food and Drug Administration’s maximum doses are based on a 150-lb healthy patient. For patients who weigh less than 150 lbs, the MRD should be calculated per their individual weight. Additionally, when administering more than one local anesthetic agent, the lowest MRD should be used to establish the maximum dosing level. There are also MRDs for vasoconstrictors (0.2 mg epinephrine per appointment for a healthy patient; 0.04 mg epinephrine per appointment for patients with relative contraindications; and 1 mg levonordefrin per appointment for all patients).1 Calculations for the maximum number of cartridges need to account for both the anesthetic and the vasoconstrictor. The lower of the two numbers is the maximum number of cartridges.
BUFFERING OF LOCAL ANESTHETICS
Buffering is the addition of sodium bicarbonate to the anesthetic solution to raise the acidic pH to a more physiologic range (pH of 7.35 to 7.45).1 This process decreases the pain on injection due to the acidic nature of an unbuffered anesthetic and speeds time of onset by increasing the proportion of available ions to penetrate the nerve membrane.1,20 Research on the buffering of local anesthetics is mixed. Some studies concluded there were no statistically significant differences between the use of buffered and nonbuffered solutions regarding injection discomfort and onset time.21,22 Others show that buffering anesthetics effectively decreases the discomfort of the injection and speeds onset.20,23–25 Buffering systems include buffering solutions and mixing devices. With one system, the clinician uses a mixing pen to add sodium bicarbonate to a traditional dental cartridge. Another system uses large vials of lidocaine and sodium bicarbonate that are mixed in a cartridge contained inside a dispenser. The clinician uses a proprietary syringe to withdraw buffered anesthetic from the dispenser. There are no significant contraindications for using buffered anesthetics. Mixing systems provide a level of control that ensures precise buffering. If too much buffering solution is added, the anesthetic will lose effectiveness, and tissue damage can result if the pH of the solution is above 7.8. For this reason, a mixing system is recommended.
ALTERNATIVE ANESTHESIA DELIVERY METHODS
Topical anesthesia can also be provided via mouthrinse. Dyclonine hydrochloride (HCl) is a ketone-based topical anesthetic that can be used in a rinse formulation to provide widespread topical anesthesia throughout the oral cavity. Currently, dyclonine HCl rinse can be obtained through compounding pharmacies. It is used in dentistry in 0.5% and 1% solutions. Dyclonine HCl is the anesthetic used in a brand of oral lozenges. For patients who have documented allergies or sensitivities to amide- or ester-type anesthetics, this may be a good option for soft tissue pain control during dental hygiene procedures.
Dyclonine HCl mouthrinse has an onset of 2 to 10 minutes and lasts 30 to 60 minutes. The maximum recommended dose is 200 mg (20 mL of a 1% solution, 40 mL of a 0.5% solution).1,11 The rinse is contraindicated in patients with allergies to dyclonine or any component of the formulation.26
The United States Food and Drug Administration (FDA) has specific prescribing rules governing compounded prescriptions. Clinicians should be aware of these regulations prior to using compounded prescriptions.
In 2016, the FDA approved an intranasal mist for maxillary anesthesia. The mist is a combination of 3% tetracaine HCl (ester anesthetic) and 0.05% oxy-metazoline HCl (vasoconstrictor used in over-the-counter nasal sprays). The mist is designed to provide anesthesia for teeth #4 to #13 and A through J in patients weighing more than 88 lbs. The mist is administered on the same side as the tooth to be treated. For example, to anesthetize #13, the mist would be administered in the left nostril. Studies indicate anesthetic success ranging from 83% to 88%, with “anesthetic success” defined as the ability to complete restorative procedures without the use of “rescue” injected anesthetics.27–29 This may be a good option for patients who are needle-phobic or particularly anxious regarding the local anesthetic portion of the dental appointment.
Another alternative delivery method is computer-controlled local anesthesia delivery (CCLAD). The introduction of this technology has simplified pain management in the dental setting. CCLAD devices provide local anesthetic drugs in a slow and controlled manner, which is ideal for use in patients who fear injections. For sales reps, this technology presents a golden opportunity to generate new sales.
The mist offers an onset time of 10 minutes. Each 0.2 mL nasal spray unit (which comes as a prefilled, single dose) delivers 6 mg of tetracaine and 0.1 mg of oxymetazoline. Dosing for children weighing more than 88 lbs is two sprays, delivered 4 to 5 minutes apart. For adults age 18 and older, the dosing is two sprays administered 4 to 5 minutes apart, with an additional one spray if anesthesia has been unsuccessful.
This mist is contraindicated in patients with allergies to tetracaine or other ester anesthetics, oxymetazoline, and ρ-aminobenzoic acid (PABA); uncontrolled hypertension; active thyroid disease; patients who experience frequent nosebleeds; and individuals with a history of methemoglobinemia or those at risk for developing methemoglobinemia. It should not be used in patients taking monoamine oxidase inhibitors, nonselective beta adrenergic agonists, or tricyclic antidepressants. Patients should discontinue use of other oxymetazoline-containing products 24 hours prior to receiving the intranasal mist, in addition to avoiding any concomitant use of intranasal products. Side effects of the mist include runny nose, nasal congestion, nasal discomfort, increased tearing, and minor change in blood pressure, which is most likely due to the oxymetazoline.27–29
Oral health professionals who are well versed in the selection of local anesthetic materials will be best able to choose the optimum solution for individual patient needs. As a dental sales rep, you are in the ideal position to introduce and share the benefits of new anesthetic products and product formulations. With a range of anesthetic agents and related products available, and you on the sidelines seeking out the hottest new products and trends, clinicians can deliver high-quality patient care that is devoid of pain.
This article is adapted from one previously published in Dimensions of Dental Hygiene.
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- Garisto GA, Gaffen AS, Lawrence HP, Tenenbaum HC, Haas DA. Occurrence of paresthesia after dental local anesthetic administration in the united states. J Am Dent Assoc. 2010;141:836–844.
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- Moore PA, Haas DA. Paresthesias in dentistry. Dent Clin North Am. 2010;54:715–730.
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- Kanaa Whitworth JM, Corbett IP, Meechan JG. Articaine and lidocaine mandibular buccal infiltration anesthesia: A prospective randomized double- blind cross-over study. J Endod. 2006;32:296–298.
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- Jeffcoat MK, Geurs NC, Magnusson I, et al. Intrapocket anesthesia for scaling and root planing: Results of a double-blind multicenter trial using lidocaine prilocaine dental gel. J Periodontol. 2001;72:895–900.
- Winning L, Polyzois I, Nylund K, Kelly A, Claffey N. A placebo-controlled trial to evaluate an anesthetic gel when probing in patients with advanced periodontitis. J Periodontol. 2012;83:1492–1498.
- Derman SH, Lowden CE, Hellmich M, Noack MJ. Influence of intra-pocket anesthesia gel on treatment outcome in periodontal patients: A randomized controlled trial. J Clin Periodontol. 2014;41:481–488.
- Derman SH, Lowden CE, Kaus P, Noack MJ. Pocket-depths-related effectiveness of an intrapocket anaesthesia gel in periodontal maintenance patients. International Journal of Dental Hygiene. 2014;12(2):141–144.
- Adriani J, Mehta D, Naraghi M. Mixtures of local anesthetics: The effectiveness of combinations of benzocaine, butamben, and tetracaine topically. Anesthesiology Review. 1981;8(12):15–19.
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- Jones J. A new era in pain management: Non-injectable anesthesia for scaling & root planing procedures. Available at: oralhealthgroup.com/features/a-new-era-in-pain-management-non-injectable-anesthesia-for-scaling-amp-root-planing-procedures. Accessed November 9, 2017.
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- Whitcomb M, Drum M, Reader A, Nusstein J, Beck M. A prospective, randomized, double-blind study of the anesthetic efficacy of sodium bicarbonate buffered 2% lidocaine with 1:100,000 epinephrine in inferior alveolar nerve blocks. Anesth Prog. 2010;57:59–66.
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- Hersh EV, Pinto A, Saraghi M, et al. Double-masked, randomized, placebo-controlled study to evaluate the efficacy and tolerability of intranasal K305 (3% tetracaine plus 0.05% oxymetazoline) in anesthetizing maxillary teeth. J Am Dent Assoc. 2016;147:278–287.
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From MENTOR. December 2017;8(12): 28-30, 32-33.