An In Vivo Comparative Analysis of Pain Perception in Children Following Lidocaine Gel, Clove Oil, and Precooling for Intraoral Injections: A Pilot Study

Abstract

Background

Dental anxiety about injections are common challenge in pediatric dentistry, often leading to delayed dental treatment.

Aim

The aim of the study was to evaluate the anesthetic effectiveness of three different topical agents in pediatric dental procedures.

Settings and design

The study was a cross-sectional in vivo study carried out in the department of pediatric and preventive dentistry. Ninety children were chosen using convenience sampling and divided into three groups based on the topical anesthetic agent administered.

Materials and methods

The procedure included anxiety assessment using the Modified Venham Picture Scale (MVPS) before and after the procedure, and pain perception was measured with the visual analog scale (VAS) and sound, eye, and motor scale (SEMS). Group A received 2% lidocaine gel, group B experienced precooling of the injection site with an ice cone, and group C was treated with clove oil, followed by a 0.9 mL infiltration injection of 2% lidocaine with 1:1,00,000 epinephrine using a 30-gauge needle for all groups.

Statistical analysis

Variations in scores of the MVPS, VAS, and SEMS within and between the three groups were examined with the Kruskal–Wallis test. Spearman's correlation was employed to assess the relationships between the three scales with statistical significance set at p < 0.05.

Results

Clove oil demonstrated the best anesthetic properties and exhibited the least pain perception among all groups.

Conclusions

Natural options like clove oil and precooling with ice cones may serve as cost-effective alternatives to lidocaine gel in reducing pain and anxiety during pediatric dental procedures.

How to cite this article

Sudha PM, Mathew BM, Rajasudhakar H, et al. An In Vivo Comparative Analysis of Pain Perception in Children Following Lidocaine Gel, Clove Oil, and Precooling for Intraoral Injections: A Pilot Study. Int J Clin Pediatr Dent 2024;17(12):1394–1398.

Introduction

Dental anxiety and the fear of injections are common challenges for dental practitioners, especially when treating children. This fear can lead to delayed dental care and ineffective pain management. Profound local anesthesia is essential for successful treatment, but reducing injection pain is crucial.¹ Ice, used for topical anesthesia in the 19th century, is well-documented for reducing skin injection pain.^2,3 However, its application in dentistry is limited, with few studies available. Clove oil, a natural product, has been used traditionally for toothache relief and contains eugenol, known for its anesthetic properties. Both ice and clove oil can be cost-effective and readily available options for topical anesthesia in dental procedures.⁴

The study aims to evaluate the pain and perception anxiety levels resulting from the topical application of lignocaine gel, ice cone, and clove oil prior to intraoral injections using pain intensity and anxiety assessment tools used in children.

Materials and Methods

Study Setting

The study was carried out in the department of pediatric and preventive dentistry, from the period of 2 months from August 8 to October 8, 2022. Prior to commencing the study, ethical clearance was obtained from the Institutional Ethics Committee (IEC/Approval no. 257). The study participants were informed about the purpose of the study, and following case history and examination, all participants provided informed consent.

Sample Size

In this study, the sample size was determined based on the methodology outlined by Anantharaj et al.,⁴ using the formula n = 2(Zα/2 + Zβ)²σ²/f². In the formula, “n” is the sample size per group, Zα/2 is the Z-score for the 5% significance level, Zβ is for the desired power, 2σ² represents population variance, and “f” indicates the effect size (0.434 in this case). The calculated minimum required sample size was around 75. This sample size was considered adequate to detect an effect size of 0.434 with 80% statistical power at a 5% significance level.

Study Design, Participants, and Study Groups

The study was an in vivo cross-sectional study and included 90 children selected through convenience sampling and divided into three groups based on the topical anesthetic agent administered. Group A consisted of individuals who were administered 2% lidocaine gel (LOX-2% jelly, Neon Laboratories Ltd.), group B received an ice cone, and group C had clove oil (Pain Out Dental Gel, Colgate Palmolive Ltd.) applied to the injection site. Inclusion criteria considered were children aged 8–10 requiring local anesthetic infiltration for pulpotomy and pulpectomy procedures in their upper molars were included. Exclusion criteria considered were children with a history of allergic reactions to local anesthesia, those presenting with dental abscesses and draining sinuses, cases involving external resorption, and uncooperative children.

Procedure

The patient's anxiety levels were recorded before and after the procedure using the Modified Venham Picture Scale (MVPS). To evaluate the patient's pain perception before and after the procedure, two scales were utilized: the visual analog scale (VAS) and the sound, eye, and motor scale (SEMS).⁵ Prior to administering the injection, the mucosa at the injection site was dried with a cotton swab for 30 seconds. In group A, 2% lidocaine gel was topically applied and left for 1 minute, in group B, the injection site was precooled with an ice cone for approximately 1 minute, and in group C, clove oil was applied to the injection site for about 1 minute. Following this, an infiltration injection of 0.9 mL of 2% lidocaine with 1:1,00,000 epinephrine was administered using a 30-gauge needle for participants of all three groups. The preparation of the ice cone was carried out through a two-step process. First, sterile latex gloves were filled with distilled water, and their openings were tightly secured. Subsequently, these water-filled latex gloves were placed in a freezer and left to freeze for approximately 6 hours, creating the ice cone for the procedure.^4,6

Statistical Methods

The Kruskal–Wallis test was used to compare MVPS scores among the three groups both before and after the intervention and to compare VAS and SEMS scores among the lignocaine, ice cone, and clove oil groups after the intervention. Post hoc analysis (Dunn–Bonferroni test) was used to examine specific pairwise differences between groups and identify which groups show statistically significant differences in postintervention VAS and SEMS scores. Spearman's analysis was used to calculate correlation coefficients between MVPS, VAS, and SEMS scores to assess the relationships between these three scales. A p ≤ 0.05 was considered statistically significant.

Results

Table 1 shows that prior to any intervention, clove oil had the highest mean MVPS score (1.90 ± 1.24), followed by ice cone (B) with a slightly lower score (1.60 ± 0.67), and lignocaine (A) had the lowest MVPS score (1.63 ± 1.09). The Kruskal–Wallis test revealed no statistically significant differences in MVPS scores among the three groups before the intervention (p = 0.667). Following the interventions, the pattern of MVPS scores changed. Ice cone (B) had the highest mean MVPS score (2.47 ± 0.97), lignocaine (A) had a moderate score (2.37 ± 1.12), and clove oil (C) had the lowest mean MVPS score (2.27 ± 1.33). Similar to the preintervention results, the Kruskal–Wallis test did not identify any statistically significant differences in MVPS scores among the three groups after the intervention (p = 0.673).

Table 1:

MVPS comparison between groups (groups A, B, and C)

MVPS		N	Mean ± SD	Mean rank	Kruskal–Wallis test statistic value	p-value
Before intervention	Lignocaine	30	1.63 ± 1.09	1	0.810	0.667
	Ice cone	30	1.60 ± 0.67	2
	Clove oil	30	1.90 ± 1.24	3
	Total	90	1.71 ± 1.03
After intervention	Lignocaine	30	2.37 ± 1.12	2	0.792	0.673
	Ice cone	30	2.47 ± 0.97	3
	Clove oil	30	2.27 ± 1.33	1
	Total	90	2.37 ± 1.14

MVPS, Modified Venham Picture scale; N, size; SD, standard deviation; *statistically significant (p < 0.05)

Table 2 assessed the postintervention VAS scores for three groups: lignocaine, ice cone, and clove oil. The mean VAS scores for each group were as follows: lignocaine (4.1 ± 2.46), ice cone (3.56 ± 1.56), and clove oil (2.8 ± 1.62). The Kruskal–Wallis test showed a statistically significant difference in VAS scores between the groups (p = 0.043). Post hoc analyses revealed specific pairwise differences between the groups. Statistically significant differences were observed in postintervention VAS scores between the lignocaine group (A) and the clove oil group (C) and between the ice cone group (B) and the clove oil group (C) with p-value of 0.019 and 0.051, respectively.

Table 2:

VAS comparison between all three groups after intervention

VAS	N	Mean ± SD	Mean rank	Kruskal–Wallis test statistic value	p-value	Post hoc analysis†
						Comparisons	Test statistic	p-value
Lignocaine	30	4.1 ± 2.46	3	6.270	0.043*	A vs B	2.567	0.699
Ice cone	30	3.56 ± 1.56	2			A vs C	15.483	0.019*
Clove oil	30	2.8 ± 1.62	1			B vs C	12.917	0.051*
Total	90	3.48 ± 1.98

A, lignocaine; B, ice cone; C, clove oil; N, size; SD, standard deviation; VAS, Visual Analog Scale; *statistically significant (p < 0.05); ^†Dunn–Bonferroni post hoc test

Table 3 shows the SEMS comparison between all three groups. After the intervention, participants who received lignocaine (A) reported a mean SEMS score of 1.76 (± 0.67). In contrast, the ice cone (C) group displayed a mean SEMS score of 1.23 (± 1.59) following the intervention and participants of clove oil (C) group reported the lowest mean SEMS score after the intervention with a score of 1.03 (± 1.64). The Kruskal–Wallis test for the comparison of SEMS scores among the lignocaine, ice cone, and clove oil groups yielded highly significant results (p = 0.001). The post hoc analysis of SEMS scores revealed a statistically significant difference (p = 0.008) when comparing lignocaine (A) and ice cone (B) group as well as between lignocaine (A) and clove oil (C) with p-value of p = 0.000. However, no statistical difference was noted between ice cone (B) and clove oil (C) with a p-value of 0.348.

Table 3:

SEMS comparison between all three groups

SEMS	N	Mean ± SD	Mean rank	Kruskal–Wallis test statistic value	p-value	Post hoc analysis†
						Comparisons	Test statistic	p-value
Lignocaine	30	1.76 ± 0.67	3	13.780	0.001*	A vs B	16.683	0.008*
Ice cone	30	1.23 ± 1.59	2			A vs C	22.617	0.000*
Clove oil	30	1.03 ± 1.64	1			B vs C	5.933	0.348
Total	90	1.34 ± 1.98

A, lignocaine; B, ice cone; C, clove oil; N, size; SD, standard deviation; SEMS, sound, eye, and motor scale; *statistically significant (p < 0.05); ^†Dunn–Bonferroni post hoc test

Table 4 presents the correlation among all groups with respect to three different scales: the MVPS, the VAS, and the SEMS. The correlation coefficient between MVPS and VAS was 0.471 with p-value of 0.000 which showed a statistically significant positive correlation. Similarly, there was a statistically significant positive correlation between MVPS and SEMS of 0.460 with p-value of 0.000. The correlation coefficient between VAS and SEMS was also found to have a statistically significant positive correlation of 0.432 with the p-value for this correlation being 0.000.

Table 4:

Correlation among all groups in regard to MVPS, VAS, and SEMS

Spearman's rho in all groups		MVPS	VAS	SEMS
MVPS	Correlation coefficient	1.000	0.471*	0.460*
	Sig. (two-tailed)	–	0.000	0.000
	N	90	90	90
VAS	Correlation coefficient	0.471*	1.000	0.432*
	Sig. (two-tailed)	0.000	–	0.000
	N	90	90	90
SEMS	Correlation coefficient	0.460*	0.432*	1.000
	Sig. (two-tailed)	0.000	0.000	–
	N	90	90	90

MVPS, Modified Venham Picture Scale; SEMS, sound, eye, and motor scale; VAS, Visual Analog Scale; *Spearman's correlation (rho value) is significant at the 0.05 level (two-tailed)

Discussion

Dental injections can be a source of considerable fear and anxiety, particularly for pediatric patients. The prospect of experiencing pain from a needle prick is a common concern among children, and this fear can have a detrimental impact on their dental health and their willingness to receive necessary treatment. Consequently, dental professionals have explored various approaches, both pharmacological and nonpharmacological, to mitigate these anxieties and enhance the overall dental experience for children. Among the methods employed, the application of topical anesthetics has emerged as a standard practice for minimizing the discomfort associated with needle injections during dental procedures.^4,7

In the current study, children aged 6–8 were specifically chosen for examination. This selection was based on their improved cognitive and cooperative abilities, making them more cooperative to dental procedures and able to respond to the various assessment tools employed in the study.⁸ To assess the effectiveness of the chosen topical anesthetics and their impact on patient experience, the study utilized three standard assessment tools which are used extensively to assess the pain perception and anxiety levels in children. The first tool is the MVPS which uses visual representations to measure and understand anxiety levels. Its use of pictorial representations is particularly advantageous when assessing anxiety in children and provides a reliable response instead of expressing their emotional state verbally. The second tool was the VAS tool which indicates their pain perception with endpoints representing the spectrum of pain intensity, enabling patients to mark their current pain level.⁹ The final tool used in the present study was the SEMS to evaluate the relationship between pain and observable reactions which encompasses a range of reactions, including eye movements, bodily responses, verbal expressions of discomfort, and the intensity of pain sensations. The three tools were employed at various intervention stages to ensure the collection of precise, dependable, and replicable data regarding the pain perception and anxiety levels associated with the three interventions under investigation in the study.¹⁰

The current study demonstrated that clove oil exhibited superior anesthetic properties compared to lignocaine gel, corroborating findings from previous research.^4,11 There is a clear need for an agent capable of alleviating the pain caused by needle injections at the injection site in children. This not only helps condition their mindset but also fosters a positive attitude towards dental procedures. After reviewing various agents documented in the literature, this study has identified clove oil as a suitable candidate for inducing a natural anesthetic effect with minimal irritation when applied topically. Interestingly, the children participating in the study exhibited no reluctance in applying it to the mucosa, likely due to their familiarity with its aroma, commonly associated with its use in Indian cuisine. The reason for using such plant-based or derived agents such as clove oil, can be attributed to its active constituents, including eugenol, eugenyl acetate, and gallic acid. These compounds contribute to the oil's antimicrobial, anti-inflammatory, analgesic, and anesthetic properties. Clove oil being both organic and readily accessible, holds promise as a natural and effective alternative for reducing pain and anxiety during dental procedures, underscoring the potential of plant-based therapeutic approaches making it a valuable resource in dental care.¹²

A few factors that must considered when utilizing plant-based or derived extracts are the concentration and purity of the extract. As with all natural extracts, a local patch test is mandatory prior to its application especially on the skin or oral mucosa to detect latent allergic reactions. In the present study, clove oil of 4.7% concentration was used which is commercially available and has shown not to trigger any hypersensitive reaction. Another reason for considering clove oil in the present study is its widespread consumption owing it to a staple spice within the Indian diet.

The concept of “dose makes the poison” is applicable when dealing with plant-derived extracts. One method for managing exposure and controlling concentration is by employing a carrier or vehicle that dilutes the extract while facilitating the action of its active components at the intended site. It is essential that the chosen carrier or vehicle does not interact with the extract in a manner that diminishes or enhances its efficacy. In this study, the carrier used for clove oil was hydroxyethyl cellulose gel, and the nature of the clove extract, having oil-like properties, ensured that it did not interact with the extract, thus preserving both its function and shelf life.

The study also explored the concept of precooling the injection site, which was found to be an effective method for reducing pain. This approach leverages localized cooling to decrease tissue metabolic rate and induce vasoconstriction, leading to a reduction in the influx of inflammatory mediators and edema. Precooling is believed to inhibit pain signal transmission, neuromuscular transmission, and muscle tone, ultimately raising the pain threshold.^13,14 In the present study, the participants willingly permitted the topical application of ice cones to the mucosa, shaping them according to their preferences. One notable advantage of these cones is that, due to the playful nature of children and the use of frozen water, there was no reluctance among the children to place them at the injection site. Another significant advantage is the absence of side effects when using ice cones, as any remaining traces would simply be water, easily removed using a suction device. The study revealed that ice cones showed a lower mean VAS score compared to lignocaine, suggesting that participants in the ice cone group experienced less pain after the intervention than those in the lignocaine group. However, it is worth noting that this difference was not statistically significant when compared to lidocaine and clove oil.

The study has certain limitations, such as the relatively small sample size in each group and the specific use of a 30-gauge injection needle, which may impact the generalizability of the results.¹⁵ Another limitation is that the choice between these methods is subjective and the threshold of anxiety varies not only from one patient to another but also from the specific dental procedure being performed.

Conclusion

In this study, clove oil was shown to be the most effective in reducing pain perception, as shown by VAS scores, while also effectively lowering pain perception levels according to the SEMS. Its natural, cost-effective nature makes it a compelling choice for pain relief during dental procedures. Ice cones, although not as powerful as clove oil, offered a moderate reduction in pain compared to lignocaine, making them a viable alternative for those averse to traditional anesthetics.

Clinical Significance

Clove oil is an effective and natural alternative to traditional anesthetics for reducing pain during pediatric dental procedures. The use of ice cones as a noninvasive pain management method was well-accepted by children, offering a viable option to conventional treatments. These findings suggest that incorporating such natural and nonpharmacological approaches can enhance patient cooperation and improve the overall dental experience for young patients, potentially adopting positive long-term oral health habits.

Orcid

Mathew Jacob https://orcid.org/0000-0003-2797-8159