|Year : 2016 | Volume
| Issue : 1 | Page : 38-41
Evaluation of efficacy of 2% lidocaine gel and 20% benzocaine gel for topical anesthesia
Amit Garg1, Nisha Garg2, Damanpreet Kaur2, Sunila Sharma3, Ibrahim Abu Tahun4, Rajneesh Kumar5
1 Department of Oral and Maxillofacial Surgery, Sri Sukhmani Dental College and Hospital, Dera Bassi, Mohali, Punjab, India
2 Department of Conservative Dentistry and Endodontics, Bhojia Dental College and Hospital, Baddi, Solan, Himachal Pradesh, India
3 Department of Pediatric and Preventive Dentistry, Bhojia Dental College and Hospital, Baddi, Solan, Himachal Pradesh, India
4 Department of Endodontics, University of Jordan, Amman, Jordan, Jordan
5 Department of Conservative Dentistry and Endodontics, JCD Dental College, Sirsa, Haryana, India
|Date of Web Publication||21-Jun-2016|
House No. 2347, Sector 23C, Chandigarh
Source of Support: None, Conflict of Interest: None
Aim: The objective of this study was to determine the pain produced from needle insertion at bilateral labial site prepared with topical application of 2% lidocaine gel, 20% benzocaine gel, and placebo paste at subsequent visits in a same patient.
Materials and Methods: Forty healthy individuals aged 18-30 years old were subjected to three sessions in which they were treated with 2% lidocaine gel, 20% benzocaine gel, and placebo paste. in all sessions, a 26-gauge needle was inserted in maxillary labial mucosa before and 1 min after the drug application. Immediately, after needle insertion, participants indicated pain intensity on visual analog scale (VAS).
Results and Conclusions: Pain responses were compared based on subjects' self-report using VAS. Results showed that lidocaine and benzocaine were equally effective, and both were better than placebo in reducing the pain of needle insertion.
Keywords: Benzocaine; lidocaine; pain; topical anesthetics; visual analog scale.
|How to cite this article:|
Garg A, Garg N, Kaur D, Sharma S, Tahun IA, Kumar R. Evaluation of efficacy of 2% lidocaine gel and 20% benzocaine gel for topical anesthesia. Endodontology 2016;28:38-41
| Introduction|| |
Pain control is an integral part of modern dentistry.  Since patients' opinions are based on the quality of anesthesia a dentist can provide, good anesthesia contributes more to the success of a procedure than the actual skill of a dental surgeon. Needle injection of local anesthetic is the most common modality of pain control used today. The actual method of giving anesthesia is painful because of stimulation produced by the needle during insertion and injection of the anesthetic solution. Although the exact mechanism of pain is not known, factors such as method of injection, sensitivity of tissue at the site of injection, size and shape of injection needle, and properties of anesthetic solution affect the degree of pain produced by local anesthetic.  For a comfortable treatment, it is important to have a pain-free method of administering local anesthesia for a dental patient. Topical anesthetics are a boon to dentists in their attempts for pain-free injections. Topical anesthetics control pain perception and hence, alter the pain reaction of an individual.  They act by blocking the transmission of signals from the terminal fibers of the sensory nerves. Their effects are limited to control the painful stimuli occurring on or just beneath the mucosa.  Many clinical studies have shown the effectiveness of such drugs along with their advantages and disadvantages, others have shown that they are no more effective than placebo. ,,, However, psychoanalysis of these studies has shown that these variable results occur because of methodological problems such as low sensitivity of pain scales, long period of application, and application of topical anesthetic in an area of low sensitivity. many factors influence the efficacy of topical anesthetics such as topical anesthetic agent and its concentration, psychological factors, duration, and site of application.  Various agents are available today for topical analgesia. While lignocaine serves as the gold standard,  benzocaine is also known for its excellent surface anesthetic properties.  Employing the methods used by Svensson and Petersen,  the aim of this study was to evaluate the efficacy of 2% lignocaine gel, 20% benzocaine gel, and placebo paste in reducing the pain associated with intraoral injections.
| Materials and Methods|| |
Forty healthy adults aged between 18 and 30 years were selected by simple random selection criteria. The selected participants had normal healthy gingiva, were free from any systemic diseases, and did not report allergy to any of the components of the drugs to be used in the study. Informed consent was obtained from the participating subjects before starting the study. They were informed that they would be given drugs and placebo on a double-blind basis.
The drugs used in this study were 2% lidocaine gel, 20% benzocaine gel, and placebo paste. Petroleum jelly (Vaseline) was used as a placebo paste in this study.
The participants were subjected to three sessions of drug application at an interval of 5 days. The subjects were topically treated with one of the above drugs in random order. The gingiva in relation to the maxillary right central incisor was chosen as the test site in all the subjects. Following isolation, the test area was dried using sterile gauze. The topical anesthetics were applied with moderate pressure with rubbing motion for 30 s and left for 1 min. The blunt end of a ball-ended burnisher was used to check the effectiveness of anesthesia. At each session, a 26-gauge needle was injected into the labial mucosa after drug application. During and immediately after the needle insertion, each participant quantified the pain perceived using a 10-point visual analog scale (VAS).  The VAS used in the present study was about the size of a small plastic ruler [Figure 1]. One end of the scale had "no hurt" written on it whereas the other end had "worst hurt" written on it.
All the obtained data were subjected to statistical analysis. A repeated measure two way analysis of variance (ANOVA) with fixed effects was used to analyze the data. The topical anesthetic agents, placebos, and sex of the patients were the independent variables.
| Results|| |
The mean score values of VAS score after 2% lidocaine gel, 20% benzocaine gel, and placebo paste application were 1.2, 1.12, and 3.6, respectively [Table 1] and [Graph 1 [Additional file 1]].
|Table 1: Mean score values with 2% lidocaine, 20% benzocaine, and placebo|
Click here to view
ANOVA showed that the effects of at least two treatments were different (P = 0.001). there was a significant difference between the two drugs and placebo paste (P = 0.001) and nonsignificant difference between the two drugs (P = 0.829).
| Discussion|| |
The local anesthetics in routine clinical use today may be divided into two broad groups: - agents containing an ester linkage such as benzocaine and agents containing an amide linkage such as lidocaine.  Topical anesthetics exhibit pharmacological as well as psychological benefits. Data regarding the efficacy of topical anesthetics are sparse, and results are contraindicatory. The present study was conducted to evaluate the efficacy of 2% lidocaine gel, 20% benzocaine gel, and placebo paste in reducing the pain of intraoral injections. For this, forty healthy subjects were selected and subjected to three sessions at an interval of 5 days. The subjects were topically treated with topical anesthetics and placebo in a random order. The maxillary labial site was chosen for injection due to ease of access and isolation so that the time of onset of action of the drugs could be accurately determined. the method used for application of topical anesthetic in the present study was selected to increase the depth of penetration which is based on the principle that the duration of application of the anesthetic influences the amount of penetration.
Giddon et al. compared topical anesthetics in different applications and dosage forms and reported that there was no difference among 20% benzocaine, 5% lidocaine, and placebo, when applied for 30 s on palate using 25-gauge needle.  However, in our study, when labial injections were carried out, 2% lignocaine gel and 20% benzocaine gel were equally effective in reducing the pain caused by insertion of needles into the tissues and both were better than placebo paste.
Keller  showed no difference between topical anesthetic (18% or 20% benzocaine) and placebo in reducing the injection pain whereas Yaacob et al.  reported that topical anesthetic was superior to placebo.
Our results did not match with those of Gill and Orr,  which showed nonsignificant difference between applications of topical anesthetic and placebo. The discrepancy may be because of different methodologies used by them. Since Gill and Orr used a 5-point descriptive scale for pain assessment, they may not have noted the difference between topical anesthetics and placebo.
The present study is the extension of earlier studies which showed that these anesthetics are also effective in the palatal mucosa where injection is more painful.
Many studies have shown the effectiveness of topical anesthetics in comparison to placebo with variable results. In fact, the needle was inserted in the mucovestibular fold, an area in which a noxious stimulus produces low-intensity pain. , Adults were selected as subjects in this study rather than children because of developmental, cognitive, and emotional differences between adults and children and assessment of pain is more difficult in children. 
Results of our study indicate that a clinician should prefer to apply topical anesthetic before injection because it definitely results in a reduction of pain intensity. Although patients may still experience pain even after application of topical anesthetic, it shows one should put emphasis on more effective ways of controlling pain.
| Conclusions|| |
Based on the results of our study, the following conclusions can be drawn:
- Two percent lidocaine gel is equally effective to 20% benzocaine gel in reducing the pain intensity of needle insertion
- Both 2% lidocaine gel and 20% benzocaine gel are better than placebo in reducing pain of needle insertion.
As the number of studies on this subject is sparse and the clinical results are mixed, an attempt has been made to explain the results on a pharmacological basis. However, further studies are required for topical anesthetics with an improved formulation more suitable for mucosal application before their routine use in dentistry.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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