In pediatric dentistry, it is essential to reduce the pain, anxiety, and fear induced by local anesthetic (LA) injection so that the patient cooperates during dental treatment. According to the literature, about 14% of 4- to 11-year-olds are anxious while visiting a dental clinic, and injections are their biggest fear [1]. Inadequate pain management measures for local anesthesia may result in a negative dental experience, which may lead to dental fear and anxiety, and to the future avoidance of dental treatment [2].

There are several methods for reducing the pain of local anesthetic injections, such as applying topical anesthetics (e.g., benzocaine) [3], warming the local anesthetic solution [4], buffering the local anesthetic [5], and adjusting the rate of infiltration [6]. Furthermore, using a mechanical delivery device, vibrating nearby tissue while administering the injection, and exerting pressure on the injection site have also been explored to lessen the pain of local anesthetic injection [7,8].

Acupuncture is an ancient East Asian/Chinese technique that has been used for more than 2,000 years to alleviate pain. According to traditional Chinese theory, this technique alters the flow of Qi (vital energy of the body) and Xue (blood), and it can be used therapeutically for many conditions. Modern scientific investigation has demonstrated that acupuncture works by stimulating the neurological system, altering the way it processes pain signals and releasing natural painkillers, such as serotonin and endorphins, into the central nervous system (CNS) [9].

As per a systematic review, acupuncture is efficacious for many types of anxiety, but a significant drawback is the potential for bacterial infection due to reusable needles [10]. Acupressure evolved to overcome this problem. This noninvasive form of acupuncture produces the same results as acupuncture and is more suitable for children. It manually stimulates acupoints using a variety of tools, such as derma rollers, magnetic point inducers, or seeds of Vaccaria [11].

Acupressure has been shown to help with anxiety, nausea and vomiting during pregnancy, spinal anesthesia, laparoscopic procedures, and temporomandibular joint (TMJ) disorders [12], and has been suggested as a method of reducing dental anxiety in children undergoing scaling and other restorative procedures [11].

Data analyzing the effect of acupressure on the pain of local anesthetic injection in children undergoing dental procedures are sparse. Hence, the purpose of this study was to evaluate acupressure’s effect on pain during inferior alveolar nerve block (IANB) injection in children ages 5 to 10 years old.

1. Study design and setting

This randomized, double-blind, parallel-group clinical study was conducted in the Department of Pediatric and Preventive Dentistry after approval was obtained from the institute’s ethics committee (IEC/VSPM DCRC/10/2019), as well as signed informed consent from the parents and assent from the children for treatment between December 2021 and February 2022. This permission included clearance for the Sound, Eye, Motor (SEM) assessment video record of the patient observation. Study participants were assured that their personal information would be kept private and they could withdraw from the study at any time without affecting their care and treatment.

2. Sample size calculation

A sample size of 32 children per group was required to achieve 80% power and an alpha error of 5%. In consideration of a possible dropout rate of 10%, 37 children were included in each group.

3. Inclusion/exclusion criteria

The following inclusion criteria were used to select study participants: age between 5 and 10 years old, an indication for at least one clinical session of extraction requiring IANB, a Frankl’s behavior rating of 3 or 4 (positive or definitely positive), and the absence of physical and mental health conditions.

Simple randomization was accomplished with random allocation software. The software generated unique identification codes for each child, which were placed in opaque, numbered, and sealed envelopes for concealment. Children were allocated in a 1:1 ratio to the study (with acupressure) or control (without acupressure) group. Investigator 1 enrolled the children and sealed the envelopes for allocation and randomization. The operator and children were blinded to the intervention. The trial was complete after all children had undergone treatment as part of their allocated group.

4. Intervention

The chosen anxiolytic acupoint was EX-HN1, also known as the Yin Tang point, located midway between the medial ends of the two brows and shown to induce sedation and alter sympathetic-parasympathetic nerve harmony. In Chinese tradition, the application of acupressure on EX-HN1 is done to relieve stress [13].

Children randomized to the study group (acupressure intervention group) were allowed to sit and relax in a quiet environment. Investigator one (I1), who was trained at a local acupressure clinic, placed acupressure beads to apply acupressure at EX-HN1. The acupressure beads were made with self-adhesive tape that generated standardized pressure; neither supplemental pressure nor manipulation was used after the bead was secured. Beads were secured at EX-HN1 until the extraction took place. All IANB injections were administered by the same operator (I2) using the conventional technique, as described in the Handbook of Local Anesthesia. During the administration, a distraction technique was employed, with patients asked to imagine pictures of their favorite cartoon characters. After the injection, the subjective symptoms and objective signs of anesthesia were recorded [14].

Children randomized to the control group underwent the same procedure, but self-adhesive tape was applied without the bead. For the SEM assessment, video was recorded from the time the child sat in the dental chair until objective signs of local anesthesia started to appear. None of the children from either group reported adverse effects (Fig. 1).

Figure 1. CONSORT table - randomisation of sample. Allocation to respective group. n = number.

5. Outcome measurement tools

Pain during injection of the LA solution was subjectively assessed using the Wong-Baker FACES Pain Rating Scale (WBFPS) immediately following IANB administration [15].

Pain on injection was objectively assessed using the Sound, Eye, Motor scale [15].

A pulse oximeter was used to measure physiological parameters like pulse rate (PR) measured in Beats per minutes & oxygen saturation (SpO₂) expressed as percentage(%) at baseline as well as during and after LA administration between the group.

6. Statistical analysis

IBM SPSS Version 21 was used for statistical analysis. The confidence interval was kept at 95% for the assessment of all data, and a p-value < 0.05 was considered statistically significant. For categorical data, frequency analysis (number and percentage) was performed using chi-square tests, and descriptive statistics were employed for continuous data. Unpaired t-tests were used to compare continuous variables such as age, weight, Frankl score, WBFPS, and SEM score between the two groups. Analysis of variance (ANOVA) was applied to compare variables at different intervals, such as the mean SpO₂ & pulse rate at three different intervals.

In each group, five children were excluded from the study because they became uncooperative during the LA procedure, leaving a total of 64 patients in the final sample—32 patients in each group. The mean age was 8.63 ± 1.27 in the study group and 8.36 ± 1.56 in the control group. There were no statistically significant differences between the groups with respect to age, gender, or Frankl rating scale (Table 1).

Table 1

Distribution of children according to age, Frankl rating scale and gender in between study and control group.

Demographic details	Groups	Mean	Std. deviation	p-value
Age	Study (with acupressure)	8.6	1.27	0.44
	Control group (without acupressure)	8.3	1.56
Frankl rating score	Study	Score 3 - (15)	1.27	0.44
		Score 4 - (14)
	Control	Score 3 - (17)
		Score 4 - (18)
Gender	Study	Male-12	-	0.08
		Female-20
	Control	Male-17	-
		Female-15

The mean WBFPS and SEM scores were 2.00 ± 1.83 and 1.62 ± 0.65, respectively, for the study group, and 5.12 ± 2.63 and 2.84 ± 0.76, respectively, for the control group. These scores showed statistically significant differences between the two groups in Student’s unpaired t-test (Table 2).

WB-FPRS = wong baker facial pain scale; SEM = sound eye motor scale..

&md=tbl&idx=2' data-target="#file-modal"">Table 2

Comparison of WB-FPRS and SEM in between study and control group.

Pain scales	Groups	Mean	Std. deviation	p-value
(Subjective) WB-FPRS	Study	2.00	1.83	< 0.01
	Control	5.12	2.63
(Objective) SEM scale	Study	1.62	0.65	< 0.01
	Control	2.84	0.76

WB-FPRS = wong baker facial pain scale; SEM = sound eye motor scale..

Pulse rate and SpO₂ showed no statistically significant differences between the acupressure (study group) and non-acupressure (control group) groups at baseline, which suggests that the groups were well matched. During and after LA injection, however, the mean pulse rate and SpO₂ of the study and control groups demonstrated statistically significant differences. In the study group, the pulse rate and SpO₂ were not affected much during the injection compared with baseline values. However, in the control group (non-acupressure), the pulse rate increased during injection and remained elevated compared with baseline (Fig. 2).

Figure 2. Effects of EX-HN3 acupressure on pulse rate and blood oxygen saturation (SpO₂) in mandibular extraction in children. Note that the changes in pulse rate and SpO₂ were significantly reduced in the Study group during and after the local anesthetic injection for the inferior alveolar nerve block. *p < 0.05; **p < 0.01.

Acupressure is a noninvasive form of acupuncture that can be administered by direct finger pressure or the use of a bead or pellet over the targeted points. In the current study, acupressure beads (natural Vaccaria seeds with a piece of adhesive tape, commercially available as AHCS Vaccaria Seed, Hyderabad, Telangana 500027) were used over the selected points for constant pressure application. This method has an advantage over direct finger pressure in children, as it rules out operator differences.

In the current study, the treatment procedure was initiated 15 minutes after acupressure was applied. This approach is in accordance with other studies, which documented a therapeutic effect as early as 15-30 mins after the application of acupressure beads [11]. EX-HN1 was chosen as the point of acupressure application because of its reported ability to reduce anxiety [16]. The most common nerve block technique for mandibular procedures is the conventional IANB, which also is the most painful and causes more discomfort than infiltration, intrafilamentary injection, and mental nerve block [17]. The literature on the effect of acupressure on pain reduction during IANB is extremely limited [17]. To eliminate inter-examiner variability in the current study, all LA administrations were performed by the same operator, while investigator 2 assessed pain perception to avoid bias.

Since pain is extremely difficult to quantify in children, pain on injection was subjectively and objectively assessed by the Wong-Baker FACES Pain Rating Scale and the Sound, Eye, Motor scale, respectively. The Wong-Baker FACES Pain Rating Scale was chosen because it has good construct validity and adequate psychometric properties, and it is both simple to use and inexpensive [18]. In a systematic review, Tomlinson et al identified the WBFPS as a scale with extensive psychometric testing that has been used to assess both acute and disease-related pain in children [18].

The mean WBFPS and SEM scores were less in the study group than in the control group, showing statistically significant differences in pain on injection. Kumar et al. (2021) [19] evaluated the effect of acupressure on injection pain and dental anxiety in children using the two anxiolytic acupoints of Yin Tang and HT7. The researchers observed a significant reduction in pain on injection in the acupressure groups during the administration of the IANB, and dental anxiety was significantly lower in the acupressure group [19]. Physiological functions are also measured as part of the objective assessments. An increase in the sympathetic activity of the autonomic nervous system (ANS) is linked to the psychophysiological responses induced by anxiety and pain, and increased blood pressure and pulse rate are caused by changes in the cardiovascular system. A study conducted by Rayen et al. (2006) [20] concluded that pulse rate and blood pressure increase at the same time as a result of stress and anxiety at the dental clinic. A pulse oximeter, which provides a patient’s arterial hemoglobin & oxygenation levels as well as pulse rate, is one of the most sustainable methods for measuring physiologic changes. As a result, it was used in this investigation [21]. The pulse rate was significantly lower in the study group; this response could be attributed to acupressure. Avisa et al. (2018) [11] evaluated acupressure’s effect on dental anxiety using EX-HN1, HT7, and sham acupoints during scaling and restorative procedures in children. They reported a significantly lower pulse rate in the acupressure group compared with the non-acupressure group.

The use of acupressure in pediatric dentistry becomes inevitable given its effective and noninvasive approach. Erappa et al. [22] conducted a comparative study to evaluate the efficacy of hypnosis, acupressure, and audiovisual aids in reducing children’s anxiety during the administration of local anesthesia; all three distraction techniques were effective, the authors concluded. Hypnosis was most promising, followed by audiovisual aids and acupressure.

Low-level laser therapy (LLLT) in combination with acupressure was effective in controlling gag reflex in children undergoing impression-making dental procedures compared with acupressure alone [23].

Multiple sittings of acupressure bead application could not be evaluated because the dental procedure studied was completed in a single sitting.

The paucity of literature on acupressure in children makes a comparison of study results difficult.

Acupressure at the EX-HN1 point reduced pain during inferior alveolar nerve block injection in 5- to 10-year-olds and can be used as an adjunct to conventional measures like topical anesthesia.

Multiple sittings of acupressure bead application could not be evaluated because the dental procedure studied was completed in a single sitting.

The paucity of literature on acupressure in children makes a comparison of study results difficult.

None.

Conceptualisation: Devendra Nagpal; Data curation: Ayushi Shashikant Gurharikar; Formal analysis: Devendra Nagpal; Investigation: Ayushi Shashikant Gurharikar; Methodology: Devendra Nagpal; Supervision: Prabhat Singh Yadav; Gagandeep Lamba; Validation: Purva Chaudhari; Writing - original draft: Ayushi Shashikant Gurharikar; Writing - review & editing: Devendra Nagpal; Kavita Hotwani.

The authors declare no conflict of interest.