Topical Anesthesia in Pediatric Dentistry: An Update

Counter irritation or Counterstimulation: Vibration, Pressure application will come under counter-irritation, where we aim to stimulate larger A-delta fibers which block the transmission of nociception.Inhibitory neurons in the spinal cord are stimulated which reduces nociception by A-δ and C fibers.Many studies report the usage of vibration as a counter stimulant in children.[11][12][13][14][15][16][17][18][19][20][21] Some studies report that there are no significant added advantages of vibration over conventional methods in children.16 This is especially true in younger children.19 Vibration was performed mostly intraorally except in one study where vibration was performed extraorally.13 Counter stimulation by inducing vibration with a thumb is also proved to be beneficial in some studies.21 Pressure application in the injection site is also an effective counterstimulation technique for pain reduction.22 Combination of precooling and counter stimulation: Combination of precooling and vibration: for mandibular primary tooth extraction showed better results.12 Combination of precooling and pressure application with an iced tooth bud was reported to be effective 23 (Table 2).Other alternative topical anesthesia administration includes Electronic dental anesthesia, iontophoresis, sonophoresis, and liposomal encapsulation.Electronic dental anesthesia: It is a modification of TENS for intraoral usage.It delivers a small current stimulus through the tissue to reduce pain sensation.Many studies reported the usage of EDA in children.EDA is reported to have a beneficial effect with minor Surface aneStheSiaTopical anesthesia also called surface anesthesia is effective only up to very few millimeters (2-3 mm) on to the surface of mucosa applied.Efficacy of topical anesthetic is dependent upon factors such as composition (simple or compounded preparation), concentration, and contact (type and duration).Concentration: lignocaine (2-10%), benzocaine (10%) are reported to be used in children.Composition: lignocaine, benzocaine is the most common anesthetic molecule that are used either singly or in combinations to form compounded preparations.An EMLA-Eutechtic mixture of local anesthesia is an 1:1 by weight combination of lignocaine (2.5%) and prilocaine (2.5%) in emulsion form.The melting point of EMLA is low hence local anesthesia molecules remain in liquid form.Available in cream, disc form.Previously used only as a cutaneous topical anesthetic but nowadays it is being used intraorally.1 Cetacaine-it's a combination of contains benzocaine (14%) + butyl aminobenzoate (2%) + tetracaine + benzalkonium chloride (2%).[1][2][3] It is available in spray and liquid forms.Precaine-combination of 8% Lidocaine + 0.8% Dibucaine.TAC (tetracaine + adrenaline + cocaine) and XAP (xylo-adrenaline-phenylepinephrine) are few compounded topical anesthetic preparations available.In general compounded preparations are more efficacious than singular preparations.Contact (type and duration): Mode of delivery (liquid, gel, spray, patch, and cream) and duration of application of topical anesthetic can influence the efficacy of topical anesthetic but sufficient evidence is not established on the same.There is no direct relationship between the duration of topical anesthesia and its improved clinical efficacy.[4][5][6] Alternatives to Topical Anesthesia Precooling, counter-irritation (vibration), pressure application, electronic dental anesthesia, iontophoresis, sonophoresis are a few alternatives to topical anesthesia administration in children.Precooling: precooling is also called cryoanesthesia, it involves the application of cold to the surface of the oral mucosa.Unlike topical anesthesia, cryoanesthesia acts on all the cells.Many studies reported the use of precooling in children.For reducing pain due to needle insertion in block (IANB), palatal injections majority of the studies in children reported that a combination of precooling and topical anesthesia is better than the usage of topical anesthesia alone 7-10 (Table 1).