Title Lidocaine and Benzocaine are Equally Effective in Reducing Pain from Injection of Needles
Clinical Question For a patient receiving an intraoral anesthetic injection, will topical benzocaine as compared with topical lidocaine decrease the pain score felt by the patient during the injection process?
Clinical Bottom Line In patients receiving intraoral needle injections, topical lidocaine is just as effective as topical benzocaine in reducing the amount of pain felt upon injection. This is supported by several randomized controlled trials in which no statistically or clinically significant differences were seen on comparison of the two agents in reducing injection pain. Both agents are significantly more effective than a placebo.
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
11692349Adalberto/199920 healthy adult subjects, 17-26 years oldRandomized Controlled Crossover Trial
Key resultsLidocaine compared to benzocaine showed no statistically significant difference in their abilities to reduce palatal injection pain (P=0.829). Comparisons of lidocaine and benzocaine to a placebo showed a significant difference (P=0.001) in the ability to reduce pain from a palatal injection.
11338300Carr/2001Two groups of 20 healthy adults (40 subjects total), 21-70 years oldRandomized Controlled Trial
Key resultsLicocaine Delivery System (LDS) transoral patch topical anesthesia was more effective in reducing pain scores (Verbal Pain Scale, VPS, 0-4; and Visual Analog Scale, VAS, 1-100) from needle sticks than benzocaine gel (BGP) or placebo (P<0.005). When comparing LDS directly with BGP, the LDS patch proved to be more effective in reducing pain caused by needle sticks and scaling and root planing in the maxilla than the benzocaine gel (P<0.05). However in the mandible, pain from needle sticks and scaling and root planing was reduced equally by the LDS patches and the benzocaine-gel preparation.
2097909Rosivack/199060 healthy adults, 26-60 years oldRandomized Controlled Trial
Key resultsBoth lidocaine and benzocaine were significantly more effective in reducing the pain from needle injection than a placebo in the maxillary mucobuccal fold above the canine eminence (P<0.05). When comparing 20% benzocaine to 5% lidocaine in a one way analysis, no statistically significant differences in effectiveness were observed.
Evidence Search (("Benzocaine"[Mesh]) AND "Lidocaine"[Mesh]) AND "Pain"[Mesh] (("Benzocaine"[Mesh]) AND "Lidocaine"[Mesh]) AND "Pain"[Mesh](("Injections"[Mesh]) AND "Lidocaine"[Mesh]) AND "Benzocaine"[Mesh]
Comments on
The Evidence		 The Adalberto study was a randomized controlled trial that was double-blinded. A crossover design was used so the same subjects were tested in each stage. There was adequate compliance and adequate follow up. Recall bias was unlikely and there were no competing interests reported. The Carr study was a randomized controlled trial that was double-blinded. Groups were treated the same and were similar at the start of the study. There was adequate compliance from the individuals and adequate follow up. Recall bias was unlikely. Competing interests may have been present as Noven Pharmaceuticals Inc. provided the LDS patches and non-aesthetic control patches used in the study. The Rosivack study was a randomized controlled trial that consisted of groups that were treated the same and were similar at the start of the study. This was not a double-blind study. There was adequate compliance from the individuals and adequate follow up. Recall bias was unlikely and there were no competing interests reported.
Applicability These studies were done on subjects that are sufficiently representative of patients treated in most dental settings. The use of topical lidocaine or benzocaine in gel or ointment form is feasible in most dental settings, whereas the use of a transoral lidocaine patch may be less feasible in some dental settings. Utilization of topical anesthesia is very likely to be accepted by the average patient as the benefits of reducing needle injection pain and reducing discomfort/anxiety during dental procedures outweigh the harms/risks of experiencing a temporary unpleasant taste or temporary unpleasant sensation. Information is applicable to general and specialty dental practice.
Specialty (Endodontics) (General Dentistry) (Oral Surgery) (Pediatric Dentistry) (Periodontics) (Prosthodontics) (Restorative Dentistry)
Keywords topical anesthesia, lidocaine, benzocaine, injection pain
ID# 2174
Date of submission 03/14/2012
E-mail deanec@livemail.uthscsa.edu
Author Courtney Deane
Co-author(s)
Co-author(s) e-mail
Faculty mentor Gregory Spackman, DDS, MBA
Faculty mentor e-mail spackman@uthscsa.edu
   
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
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Comments and Evidence-Based Updates on the CAT
(FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs)
by Sam Asthana, and Elio Male (San Antonio, TX) on 11/28/2017
This CAT states that there is no statistically significant difference between topical lidocaine and topical benzocaine as far as needle-related pain. Newer research (PMID: 16170977) introduces further data which supports the effect of topical lidocaine over topical benzocaine. This case study alone is not strong enough evidence to refute other studies saying the two are statistically indifferent, but does cast some doubt on the clinical bottom line.