Topical Anesthetics for Dental Hygiene Procedures

Successful pain management is essential to the provision of nonsurgical periodontal therapy and other dental hygiene procedures. Today’s modern pain armamentarium is filled with options that clinicians can choose from based on patient and procedure specifics. This article focuses on the use of topical anesthetics.

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.¹This drug combination and application method have demonstrated efficacy in controlling pain during scaling and root planing and periodontal probing.^2,3 In studies comparing this topical to injected anesthetics, most patients preferred the topical option, despite experiencing more pain during periodontal therapy.^4,5 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.^6,7 This combination of anesthetics provides a short onset of action with a fairly long duration of anesthesia⁶ and has been recommended by prominent dental professionals.^8,9 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.¹ 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 minutes to 45 minutes.¹Dosing 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.

ALTERNATIVE APPLICATION 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 minutes to 10 minutes and lasts 30 minutes to 60 minutes. The maximum recommended dose is 200 mg (20 mL of a 1% solution, 40 mL of a 0.5% solution).^1,10 The rinse is contraindicated in patients with allergies to dyclonine or any component of the formulation.¹¹

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% oxymetazoline 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.^12–14 This may be a good option for pa­tients who are needle-phobic or particularly anxious regarding the local anesthetic portion of the dental appointment.

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 minutes to 5 minutes apart. For adults age 18 and older, the dosing is two sprays administered 4 minutes 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.^12–14

CONCLUSION

New local anesthesia products have entered the market over the past several years. With the range of anesthetic agents and anesthesia-related products available, clinicians can ensure good patient experiences during dental care.

ACKNOWLEDGEMENT

The author would like to thank Gail Aamodt, RDH, MS, for her clinical expertise and contribution to this manuscript.

REFERENCES

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12. 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.
13. Ciancio SG, Marberger AD, Ayoub F, et al. Comparison of 3 intranasal mists for anesthetizing maxillary teeth in adults: A randomized, double-masked, multicenter phase 3 clinical trial. J Am Dent Assoc. 2016;147:339–347.
14. Ciancio SG, Hutcheson MC, Ayoub F, et al. Safety and efficacy of a novel nasal spray for maxillary dental anesthesia. J Dent Res. 2013;92(7 Suppl): 43S–48S.

Featured photo courtesy of MOROZOVA TATIANA/HEMERA/GETTY IMAGES PLUS

From Dimensions of Dental Hygiene. July 2017;15(7):32, 34-35.