Efficacy and Pain Perception of a Comfort-in™ for Palatal Anesthesia in Pediatric Dental Patients: A Randomized Controlled Trial

Abstract

Background

Needle phobia is frequently observed in children, contributing to heightened dental anxiety, uncooperative behavior, and care avoidance. The sight or sensation of traditional anesthesia needles can provoke intense emotional responses, complicating pediatric pain management. This study assesses the Comfort-in™ needle-free jet injector as an alternative, aiming to enhance anesthetic delivery, patient comfort, and cooperation during pediatric dental procedures.

Aim

To assess the effectiveness of the Comfort-in™ system in minimizing pain during local anesthesia (LA) administration in pediatric dental procedures.

Materials and methods

This randomized controlled trial included 64 children aged 4–9 years undergoing tooth extractions involving buccal and palatal infiltrations. Participants were randomly assigned to receive anesthesia via either a conventional needle syringe (group I) or the Comfort-in™ jet injector (group II). Pulse rate, behavior, pain, and local anesthetic effectiveness were evaluated.

Results

The difference in pulse rates during LA administration and during treatment was statistically significant between the two groups (p = 0.000 and 0.000, respectively); with a lower pulse rate seen with the jet injector group, suggesting that the child had lower anxiety with the jet injector group. Similar results were seen with other parameters such as time required, LA efficacy, Wong–Baker FACES pain rating scale, and modified behavior rating scale by Taddio et al.

Conclusion

Considering the limitations of the present study, the Comfort-in™ system demonstrated effectiveness as a needle-free alternative for minimizing pain and anxiety in pediatric patients, while also significantly reducing the time required for LA administration.

How to cite this article

Naik SS, Kodical SR, Joshi A, et al. Efficacy and Pain Perception of a Comfort-in™ for Palatal Anesthesia in Pediatric Dental Patients: A Randomized Controlled Trial. Int J Clin Pediatr Dent 2026;19(2):228–233.

Introduction

Dental anxiety is a global problem that hinders the effectiveness of treatment.¹ In pediatric dentistry, pain management is one of the most crucial elements influencing the outcome of treatment.² Children who experience needle-related pain (NRP) may have an emotional and cognitive reaction to the procedure that causes them to postpone or completely avoid the treatment. Moreover, it has often been observed that the fear exhibited at the sight of a needle is far greater than the fear of undergoing dental treatment.³

Palatal injections are recognized as one of the most painful forms of local anesthesia (LA) and can quickly induce anxiety and negative pain-related behaviors in pediatric patients.⁴ This is primarily due to the dense nature of the palatal mucosa and underlying bone, which are tightly adhered to the periosteum and richly supplied with nerves. The discomfort associated with palatal infiltration results from needle penetration into this highly innervated area, as well as the pressure created by displacement of the mucoperiosteum during administration of the local anesthetic. In a study conducted by Abdellatif, 50% of children aged 6–7 years reported experiencing moderate to severe pain during the palatal infiltration process. The study also revealed an inverse relationship between anesthesia-related pain scores and children's cooperative behavior. Thus, effective pain control during palatal anesthesia can significantly benefit both the child and the clinician, facilitating more atraumatic and cooperative procedural outcomes.⁵

To address the pain and anxiety commonly associated with traditional dental needles and syringes, jet injectors were developed.³ The jet injection syringe was first invented by John F Roberts in 1933. A major advancement occurred in 1947 with the introduction of needle-free injection into clinical practice. Since then, this technology has been employed in various medical and dental procedures. The earliest dental research involving the use of a needleless jet injector was conducted by Margetis et al. in 1958.⁶

The use of pressure to safely force the anesthetic solution into oral tissues is the most distinctive feature of these needleless devices that patients find acceptable. With an onset of action of about 1 ms, the anesthetic solution enters the tissue as tiny droplets that are instantly absorbed by the nerve's myelin sheath. This dosage works best for localizing its effects without affecting blood levels throughout the body.⁶ Several jet injectors, such as INJEX and Madajet XL, have been previously documented in the literature. While these devices eliminate the use of needles, they come with notable limitations. For instance, the INJEX system requires the anesthetic delivery component to be aligned at a 90° angle to the main body, which has been associated with mucosal bleeding, anesthetic leakage into the oral cavity, and postanesthesia discomfort. Additionally, the bulky design of the Madajet XL has been reported to cause apprehension among patients.⁷

The Comfort-in™ system was developed to overcome the limitations of earlier jet injector models. As one of the latest advancements in needle-free anesthesia delivery, it utilizes a patented “liquid jet” technology to administer anesthetic solutions at high pressure in just one-third of a second. This system allows for rapid and needleless infiltration of LA. However, its efficacy in procedures involving primary molars in pediatric patients remains insufficiently explored.²

It was necessary to investigate the effectiveness of Comfort-in™ for its use to administer palatal anesthesia during extractions because studies using other needleless devices have been conducted in the past and have shown that they have positive effects such as being quick and easy to use, causing little to no pain, causing less tissue damage, and facilitating rapid drug absorption⁸ yet can cause discomfort while use hence it was necessary to explore the effectiveness of Comfort-in™ for its use to administer palatal anesthesia during extractions.

Materials and Methods

Case Selection

A total of 64 children aged 4–9 years meeting the ASA 1 criteria with a Frankl behavior rating score of 2, 3, 4; visiting the Department of Pediatric and Preventive Dentistry who required primary maxillary teeth extraction, and detailed history of no drug related allergies was obtained as well as children who had no contraindications to usage of local anesthetic agent were selected. The study adhered to the CONSORT (Consolidated Standards of Reporting Trials) statement 2010 (Fig. 1).

Fig. 1:

CONSORT diagram

Ethical Consideration

The study protocol received approval from the Institutional Ethics Committee (IREB/2024/PEDO/15). It was also prospectively registered with the Clinical Trials Registry—India (CTRI) under the identifier CTRI/2025/02/080759, maintained by the ICMR (Indian Council of Medical Research)'s National Institute of Medical Statistics (http://nims-icmr.in). Detailed explanations of the procedure were provided to the parents, and informed consent was obtained in three different languages. Parents who declined participation were excluded from the study but received standard treatment outside the study protocol.

Sample Size Calculation

The sample size was determined using G*Power software, with an alpha error set at 5%, a beta error at 20%, and a statistical power of 80%. The calculation was based on the formula: n (per group) = 2 × [Z_(1−α/2) + Z_(1−β)]²/Δ²

Based on these parameters, the estimated total sample size was 64 participants.

Grouping and Randomization

Simple random sampling was carried out using the lottery method, where identical opaque chits labeled as group I or group II were drawn by an independent observer. Based on the drawn chit, participants were randomly assigned to one of two groups: Group I (conventional needle group) or group II (jet injector group).

Procedures

Preanesthetic Procedures

The children were explained about the procedure using euphemisms to prepare the child for the upcoming treatment. Frankl behavior rating scale recorded the behavior of the child before treatment. Pulse rate was recorded as an objective measure of anxiety, and the modified behavior rating scale by Taddio et al.⁹ was used to record pain scores before treatment.

Anesthetic Process

For both groups 5% benzocaine topical anesthesia (Lignospan-O, Septodont Healthcare, India) was applied prior to LA administration. The local anesthetic agent used was 2% lignocaine with 1:80,000 adrenaline (Lignospan Special, Septodont Healthcare, India).

In group I, buccal (1 mL) and palatal (.5 mL) infiltration was administered using a conventional needle and syringe. In group II, buccal (.3 mL) and palatal (.2 mL) infiltration was administered using the needleless device Comfort-in™ system. The nozzle with the angulated nozzle cap was adapted to the palatal mucosa, followed by which the injector button was pressed to administer 0.2 mL of palatal infiltration (Fig. 2). In a similar way, using the flat nozzle cap, the injector nozzle was adapted to the buccal sulcus mucosa to administer 0.3 mL buccal infiltration as per the manufacturer's instructions (Fig. 3).

Fig. 2:

Palatal anesthesia using a jet injector

Fig. 3:

Buccal anesthesia using a jet injector

Evaluation of Pain

Subjective assessment of pain was recorded using Wong–Baker FACES pain rating scale after LA administration. Modified behavior rating scale by Taddio et al.⁹ was used to record pain scores at four intervals: before treatment, during LA administration, during treatment, and after treatment.

Evaluation of Dental Anxiety

Pulse rate was recorded as an objective measure of anxiety at four intervals: before treatment, during LA administration, during treatment, and after treatment.

Time of LA Administration

The duration of the local anesthetic delivery process via both techniques, which was initiated after topical anesthesia application, was timed using a stopwatch.

LA Efficacy

The efficacy of LA administered was assessed on a scale,⁹ ranging from 0—did not allow treatment to be completed, 1—treatment completed without pain, 2—treatment completed with mild sensitivity, 3—assessment could not be performed.

Statistical Analysis

Statistical analysis was performed using IBM (International Business Machines) SPSS (Statistical Package for the Social Sciences) Statistics for Windows, version 21.0 (IBM Corp., Armonk, New York, United States). The Student's t-test was employed to compare age distribution and intergroup differences, while the Chi-square test was used to evaluate gender distribution among participants. A p-value of <0.05 was considered indicative of statistical significance.

Results

Intergroup comparison for pulse rates yielded a statistically significant difference at two intervals during LA administration and during treatment; p = 0.000, 0.000, respectively (Tables 1 and 2).

Table 1:

Gender distribution

		Group
	Gender	I	II	Total	Chi-square value	p-value of the Chi-square test
	F	15	14	29	0.063	0.802#
	M	17	18	35
	Total	32	32	64

^#Not significant

Table 2:

Pulse rate

	Group	n	Mean	Std. deviation	p-value of the Mann–Whitney U test
Pulse rate before treatment	I	32	86.44	5.273	0.069#
	II	32	89.50	7.923
Pulse rate during LA administration	I	32	95.66	3.948	0.000**
	II	32	83.78	9.040
Pulse rate during treatment	I	32	95.53	3.943	0.000**
	II	32	81.94	9.080
Pulse rate postoperative	I	32	80.84	5.952	0.135#
	II	32	79.22	8.922

^#Not significant; **Highly statistically significant

The p-values for the modified behavior pain rating scale by Taddio et al.⁹ were used to assess pain scores at four intervals, out of which one intergroup comparison statistically significant difference was noted at three intervals: during LA, during treatment, and after treatment; p = 0.000 and 0.000, respectively (Table 3).

Table 3:

Scores of the modified behavior pain rating scale by Taddio et al.⁹

	Group	n	Mean	Std. deviation	p-value of the Mann–Whitney U test
MBPS before treatment	I	32	0.13	0.421	1.000#
	II	32	0.13	0.421
MBPS during LA administration	I	32	3.13	0.609	0.000**
	II	32	0.59	0.665
MBPS during treatment	I	32	2.28	0.581	0.000**
	II	32	0.50	0.672
MBPS after treatment	I	32	0.22	0.420	0.024*
	II	32	0.03	0.177

^#Not significant; **Highly statistically significant; *Statistically significant; MBPS, Modified behavior pain scale

In the subjective assessment of pain using the Wong–Baker FACES pain rating scale, when the scores of both groups were compared, lower scores were seen with the jet injector group. The intergroup comparison results were statistically significant; the p-value was 0.000 (Table 4).

Table 4:

Wong–Baker FACES pain rating scores

Group	n	Mean	Std. deviation	p-value of the Mann–Whitney U test
I	32	4.38	0.660	0.000**
II	32	0.59	0.665

**Highly statistically significant

The mean time required for LA administration (measured in seconds) in the control and intervention group was 90.97 ± 1.909 and 1.13 ± 0.421, respectively. Less time was required when LA was delivered using the jet injector as compared to the conventional needle. This comparison yielded a highly statistically significant difference noted with a p-value of 0.000 (Table 5).

Table 5:

Time required for LA administration

	Group	n	Mean	Std. deviation	p-value of the Mann–Whitney U test
Time required for administration (in seconds)	I	32	90.97	1.909	0.000**
	II	32	1.13	0.421

**Highly statistically significant

LA efficacy mean scores for the conventional needle and jet injector group were 1.44 ± 0.564 and 1.13 ± 0.421, respectively. with a statistically significant difference present (p = 0.012) (Table 6).

Table 6:

LA efficacy scores

	Group	n	Mean	Std. deviation	p-value of the Mann–Whitney U test
LA efficacy score grades	I	32	1.44	0.564	0.012*
	II	32	1.13	0.421

*Statistically significant

Discussion

Several factors influence a child's response to dental treatment, including age, temperament, baseline anxiety, parental anxiety, and previous dental experiences.^10,11 Sociodemographic variables such as age and gender also play a role in shaping dental anxiety. Although dental anxiety typically develops early in life, it tends to decrease with age.² LA remains a cornerstone of pain control in pediatric dentistry; however, it poses significant challenges, as children often perceive injections as both visually and psychologically threatening.¹²

To enhance patient cooperation, improve behavioral responses during dental procedures, and minimize the fear associated with needle visibility, needle-free jet injectors were introduced into dental practice as an alternative method for administering LA. The basic concept is to use spring-loaded devices to inject the anesthetic solution under pressure into the tissues, doing away with the need for needles and encouraging patients—especially kids—to have a positive attitude toward dental procedures. Among the benefits of the Comfort-in™ needleless injector are the absence of needlestick injuries, a reduction in procedure anxiety, and quicker drug absorption at the injection site. The equipment's initial cost, the popping sound it makes during injection, and the fact that most clinicians are not familiar with its use are its main drawbacks.³

Findings from the present study reveal that children who received LA using the conventional needle technique exhibited significantly elevated pulse rates during both the administration phase and the dental procedure, in comparison to those treated with the needle-less injector system. This can be explained by the fact that one of the main things that causes dental anxiety and fear during treatment is a needle-based dental injection.¹⁰ The brain receives an electrical stimulus in response to such threatening stimuli, which causes the sympathetic nervous system to become active and the heart rate to increase.¹²

Pain associated with palatal infiltration is often attributed to the use of a needle. During the procedure, the anesthetic solution is delivered to the target site after the needle passes through the alveolar mucosa and is directed toward the region near the root apex. Discomfort arises both from the mechanical penetration of the needle and the pressure exerted during deposition of the anesthetic at the injection site.⁵ This justifies the statistically significant lower scores that were recorded in the intervention group with the subjective scale for pain (the Wong–Baker FACES pain rating scale), indicating significantly less painful experience when LA was administered via the Comfort-in™ needle-less injector. Similar results have been observed by Altan et al.³ in their study, wherein they assessed pain during administration of anesthesia for pulpotomies and restorations using a needleless system (Comfort-in™) and the traditional dental needle method. Another study with similar results, conducted by Kaya and Yıldırım¹³ to assess pain perception during palatal infiltration anesthesia when delivered via traditional needle in comparison with Comfort-in™ needle-less injector, concluded that children had significantly higher pain ratings when palatal Infiltration anesthesia was administered using the traditional needle method.

In our present study, scores for the modified behavior pain rating scale by Taddio et al.⁹ were higher in the control group, yielding a statistically significant difference at three intervals, namely, during LA administration, during treatment, and after treatment. This is indicative of a higher incidence of uncooperative behavior of children in the conventional needle group (control group). Increased heart rate indicates higher dental anxiety,¹⁴ leading to an uncooperative behavior in the dental operatory.

To the best of our knowledge, this is the first study to evaluate and compare the time required for LA delivery using both conventional needle-based and needle-free techniques. Our findings indicate that the duration of LA administration was significantly shorter when using the Comfort-in™ needleless injector. Additionally, greater anesthetic efficacy was achieved with the jet injector, contributing to improved patient cooperation and completion of treatment with minimal or no pain. Both children and their parents demonstrated a clear preference for the Comfort-in™ system over the traditional method, aligning with observations reported in earlier studies.^2,6

Limitations of the Study

During the administration of the LA, it was not possible to keep the children and researchers blinded to the technique of administering the LA due to the visible differences in the device design.

Future Scope

Need for more studies to assess outcomes with a larger sample size, which, if positive, can be considered for children with special health care needs.

Conclusion

Within the limitations of the present study, it can be concluded that the Comfort-in™ system serves as an effective alternative to the conventional needle technique for minimizing needle-associated pain and anxiety in pediatric patients. Furthermore, the needle-less device significantly reduces the time required for LA administration.

Clinical Significance

• Among the few studies to investigate the use of Comfort-in™ needleless injector specifically for palatal infiltration anesthesia used for the extraction of deciduous maxillary teeth in a pediatric dental setting.

• A novel device for alleviating needle-related fear that is acceptable to both parents and children.

• Administration of LA via the needle-less device is relatively faster and requires less amount of anesthetic solution as compared to the conventional needle technique; hence, it can aid the pediatric dentist in a more efficient behavior management in cases involving dentally anxious patients.

Orcid

Shilpa S Naik https://orcid.org/0000-0002-5660-5952

Sanjana R Kodical https://orcid.org/0000-0001-8940-9408

Sonal Mali https://orcid.org/0009-0004-9358-1429