|Year : 2018 | Volume
| Issue : 3 | Page : 296-300
Effectiveness of precooling the injection site using tetrafluorethane on pain perception in children
Nithasha N Hameed1, Sharan S Sargod1, Sham S Bhat1, Sundeep K Hegde1, Muhsin Mohammed Bava2
1 Department of Pedodontics, Yenepoya Dental College, Mangalore, Karnataka, India
2 Department of Medicine, FMMCH, Mangalore, Karnataka, India
|Date of Web Publication||24-Sep-2018|
Dr. Nithasha N Hameed
Nuhman Mahal, Nekkere, Manjanady, Mangalanthy, Mangalore - 575 018, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Injection of local anesthesia is one of the most important reasons for avoidance behavior in children. Applying a topical anesthetic before injection is the most popular way to control pain; however, topical anesthetics have some shortcomings such as longer duration of action, displeasing taste, and spread of the anesthetic agent to noninjection site areas. Cryoanesthesia using refrigerant as a topical anesthesia is being studied as an alternative to overcome the shortcomings of topical anesthetics and has shown promising results. Materials and Methods: In this split-mouth design study, 50 children of aged 8–10 years who required bilateral mandibular local anesthesia administration were selected. In the first visit, application of topical anesthetic spray (lidocaine) on one side and during the second appointment cryoanesthetic tetrafluorethane on the other side was used before local anesthetic administration. Patients were asked to report their discomfort and pain using visual analog scale (VAS) (subjective method). Patients' pain perception during injection is assessed by sound, eye, and motor (SEM) scale by the dentist (objective method). Results: The results were statistically analyzed using paired Wilcoxon signed-rank test and Mann–Whitney tests. In VAS scale (subjective method), pain scores were significantly lower in tetrafluorethane group when compared with lidocaine group. In SEM scale (objective method), pain scores were lower in tetrafluorethane group when compared with lidocaine group, but it was statistically insignificant. Conclusion: Precooling the injection site using refrigerant tetrafluorethane spray has shown to be effective in eliminating pain before local anesthesia administration in children when compared with topical anesthetic lidocaine spray.
Keywords: Children, local anesthesia injection, pain, tetrafluorethane, topical anesthetic
|How to cite this article:|
Hameed NN, Sargod SS, Bhat SS, Hegde SK, Bava MM. Effectiveness of precooling the injection site using tetrafluorethane on pain perception in children. J Indian Soc Pedod Prev Dent 2018;36:296-300
|How to cite this URL:|
Hameed NN, Sargod SS, Bhat SS, Hegde SK, Bava MM. Effectiveness of precooling the injection site using tetrafluorethane on pain perception in children. J Indian Soc Pedod Prev Dent [serial online] 2018 [cited 2021 Dec 9];36:296-300. Available from: https://www.jisppd.com/text.asp?2018/36/3/296/241966
| Introduction|| |
Effective local anesthesia is the single most important pillar on which modern dentistry stands. Local anesthesia is required in any dental practice including pedodontics to alleviate the pain of dental procedures such as extractions, pulpotomies, root canal treatments/pulpectomies, drainage of abscesses, and minor oral surgical procedures. Injection of local anesthesia is one of the effective methods to reduce pain, but injection of local anesthetic itself is a great source of patient fear. Pedodontists play a greater role in minimizing the pain and discomfort during any invasive procedures on child patients.
There are several methods to reduce pain during injection of local anesthetics such as application of topical anesthetics, buffering the local anesthetics, distraction techniques, counter irritation, reducing the speed of injection, adjusting the rate of infiltration, and vibrating the surrounding tissue while administering the injection.
Topical anesthetic is most widely used before injection to control initial needle penetration pain. Disadvantages of using this are the duration of action of topical gel or sprays may vary from 5 to 10 min, displeasing taste, and spread of the anesthetic agent to noninjection site areas.
Other recommended methods to relieve the pain of injection are the use of cryoanesthesia for rapid cooling of the injection site by the use of ice/refrigerant spray. A new tetrafluorethane cryoanesthetic spray PHARMAETHYL® introduced by Septodont is a proprietary blend of 1, 1, 1,2-tetrafluorethane and dimethyl ether with natural mint flavor. It can be used in the production of topical cryoanesthesia in the oral cavity and to test pulpal vitality. It has quicker and deeper cooling action to improve efficacy with average onset time of 10–15 s. Although refrigerants have been used as a preinjection anesthetic for various medical procedures such as venipunctures and immunizations, they have not been used routinely in dentistry. There have been very few studies on knowing the effectiveness of precooling the injection site on reducing pain using refrigerant tetrafluorethane in children.
The present clinical study aimed to evaluate the effectiveness of precooling the injection site using refrigerant tetrafluorethane and to compare it with the most commonly used topical anesthetic (lidocaine) on pain perception in pediatric dental patients.
| Materials and Methods|| |
- Ethical clearance was obtained before the start of study from the Ethical Committee of Yenepoya University. The participants were informed about the study and consent was obtained from the parents
- The study included 50 children of the age group of 8–10 years who attended the Department of Pedodontics and Preventive Dentistry, Yenepoya Dental College. The children who met the following criteria were selected: children exhibiting cooperative behavior (Frankl behavior rating No: 3 and 4 who required bilateral mandibular local anesthesia nerve block administration for pulpectomies and extractions, with no history of systemic diseases (American Society of Anesthesiologists' Grade I status) and without any allergic history to local anesthesia.
Study design and clinical measurements
A single operator carried out the study using split-mouth design. Patients were given two appointments. In the first appointment, dental procedures were carried out following local anesthesia, using topical anesthetic spray (lidocaine) before injection, and on the next appointment, cryoanesthetic tetrafluorethane was used before local anesthetic administration. During inferior alveolar nerve block and lingual nerve block, 2% lidocaine was deposited slowly (1 ml/min) 26-gauge 1.5” length needle (unilock, Dispovan) following syringe aspiration.
Patients were asked to report their discomfort and pain using visual analog scale (VAS) [Figure 1]. Patients were instructed to point the position to indicate how much pain they feel. In this system, the total scores range from 0 to 10 based on measuring the distance in millimeters from the left end bar to mark made by the child on the 10 cm line anchored by happy to sad faces, with a higher score indicating more severe pain.
Examiner observation and calibration
Patients behavior during injection is assessed by sound, eye, and motor (SEM) scale [Table 1]. Total scores for SEM range from 0 to 9 based on 0–3 for each parameter.
At the end of the procedures, patients were asked the following question: (1) “Which spray would you prefer during your next visit?” Refrigerant spray was evaluated for side effects by assessing subjective and objective criteria. Subjective criteria included (1) taste disturbance, (2) burning sensation, (3) dryness, and (4) itchiness. Objective criteria included (1) ulcer, (2) staining, (3) allergy; marked as 0: absent and 1: present.
| Observations and Results|| |
The study comprised 50 patients (28 girls and 22 boys) with a mean age of 8.94 ± 0.76 years (range: 8–10 years). Intragroup comparison, i.e., VAS and SEM scale, was analyzed using Wilcoxon signed-rank test for both tetrafluorethane and lidocaine groups. Intergroup comparison was statistically analyzed using Mann–Whitney test. P < 0.05 was considered statistically significant.
Analysis of visual analog scale
In VAS scale, pain scores were significantly lower (no pain and mild pain) in tetrafluorethane group when compared with lidocaine group (mild pain and moderate pain) [Figure 2].
|Figure 2: Comparison of visual analog scale in tetrafluorethane and lidocaine groups|
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The difference between the tetrafluorethane and lidocaine groups was statistically significant (P < 0.05). All components of the VAS in the tetrafluorethane group were consistently lower than the lidocaine group. Moreover, the VAS value for the lidocaine group surpassed that of the tetrafluorethane group (P < 0.05).
The use of refrigerant compared with the use of topical anesthetic lidocaine spray significantly reduced the pain experienced during administration of local anesthetic injections (P = 0.02).
Analysis of sound, eye, and motor
There were no significant within-group differences between the values for the SEM components for either the lidocaine or tetrafluorethane groups (P > 0.05). In SEM scale, pain scores were lower (comfort and mild discomfort) in tetrafluorethane group when compared with lidocaine group (mild discomfort and moderate discomfort), but it was statistically insignificant [Figure 3].
|Figure 3: Comparison of sound, eye, and motor scale scores in tetrafluorethane and lidocaine groups|
Click here to view
| Discussion|| |
The local anesthesia is an indispensable part of dentistry. Fear of pain and discomfort from local anesthetic injection may lead to avoidance of dental treatment and systemic complications such as tachycardia and vasovagal syncope. Since control of pain is the most important aspect of guiding child's behavior, pediatric dentists are on a constant search of tools for painless administration of local anesthesia, and topical anesthetics have proven to be a boon in this attempt.
Cryoanesthesia may be induced either by the use of refrigerant sprays or with the use of ice. The chief benefit of cryoanesthesia is that it acts on all the cells of the part and not just on the nerve cells as other topical anesthetics and analgesics do, thereby producing an immediate anesthesia. The anesthesia produced by cryoanesthesia is of very short duration, but is sufficient to reduce the discomfort caused by the insertion of a needle.
Although refrigerants have been used as a preinjection anesthetic for various medical procedures, they have not been used routinely in dentistry. This study was conducted with the aim to assess the effectiveness of precooling the injection site using refrigerant tetrafluorethane on pain perception in pediatric dental patients and to compare it with topical anesthetic spray (lidocaine).
In this split-mouth design study, patients requiring bilateral local anesthetic nerve block for any of the dental procedures (pulpectomies or extractions) in either side of the lower jaw were recruited to avoid any bias since pain perception is different for each patient. Moreover, only standard inferior alveolar nerve block administration in both the sides was selected in this study since inferior alveolar nerve block is more painful than local infiltration and the area being injected in the oral cavity has direct relation to pain and discomfort perception.
26-gauge 1.5” length needle (unilock, Dispovan) was used for administration of local anesthetic injection in inferior alveolar nerve block since it is the ideal size to reduce dental injection pain, poses less risk of needle deflection and breakage, and has less difficulty in aspirating.
The results of the present study support the notion; topical cooling significantly alleviates pain and raises the pain threshold to noxious stimuli such as the penetration of the needle during the injection of local anesthetic agents for dental procedures. This was observed in VAS and SEM scales where the pain scores were less in tetrafluorethane group when compared with lidocaine group.
The same results were observed in the studies conducted by Harbert and Ghaderi et al., who applied ice to reduce pain perception associated with palatal injections. Aminabadi and Farahani reported the efficacy of 2-min application of ice before infraalveolar nerve block injection in decreasing perception of pain. There are certain limitations of using ice such as discomfort from ice contact is time dependent and the threshold is very subjective. Moreover, the method is messy and is less readily tolerated by children.
The use of a refrigerant tetrafluorethane as a preinjection anesthetic in dental anesthesia was studied by Kosaraju and Vandewalle and Lathwal et al. The findings obtained were in accordance with the present study where the use of a refrigerant as a preinjection anesthetic was more effective compared with the use of a topical anesthetic gel in reducing the pain experienced by participants who received a local anesthetic injection.
The results of the present study is in contrast to the study results of Wiswall et al., where the patient's perceived pain response to pressure, topical anesthetic spray, and precooling injection site were studied and there were no significant VAS differences among test groups and all of them were effective. In addition, 1, 1, 1,2-tetrafluorethane caused injuries in the oral mucosa when used together with pressure for 10 s. However, we did not observe any undesirable effects since care was taken to spray at a distance of 2–4 cm away from the oral mucosa to prevent damage.
The mechanism of action of refrigerant is limited to the surface of application site, and it works by creating an instant cooling effect while evaporating faster from the mucous membrane. This mechanism creates almost immediate onset of action. However, along with immediate onset, refrigerant also has the advantage of brief duration of action which is sufficient to reduce the discomfort caused by insertion of needle.
The advantage of using refrigerant 1, 1, 1,2-tetrafluorethane (HFC-134a) spray is that it is comfortable, safe, and physiologically effective with the cooling effect and pleasing taste of mint flavor, thus less likely inducing anxiety and subjective fear. The shorter duration of action of refrigerant (5–10 s) as compared with that of topical anesthetic lidocaine spray (2–5 min) could increase provider compliance by improving clinical efficiency. Another benefit is the ease of application, as the refrigerant is applied locally and there is a potential for the topical lidocaine spray to anesthetize areas other than the injection site owing to the mixing with saliva and the patient's swallowing.
In the study, the patient's behavior was evaluated for pain perception using SEM scale by the operator. SEM scale takes into account the SEM component of patients' response to stimulation and was used because it enables the assessment of the relationship between pain and the reactions which the sensation of pain generates in the patient's eyes, bodily movements, and verbal expressions of discomfort and also it can record the degree of intensity of the sensation of pain.
The other scale used in the study was VAS or Wong–Baker facial image scale which is simple to use and understood easily. Since the school-aged children who participated in this study are in the stage of concrete operations, it is an excellent measure to evaluate self-reported pain in this age group.
All patients preferred using tetrafluorethane spray when this question was asked to them “Which spray would you prefer during your next visit?” This may be because of the pleasing taste of mint flavor with faster and deeper cooling action and the refrigerant tetrafluorethane had significantly reduced pain both during insertion of needle and during deposition of solution when compared to the topical lidocaine spray.
It was observed from subjective and objective criteria that tetrafluorethane spray was well accepted by children with no undesirable effects during the study.
The present study has its own limitations. The design of the present study could not support a double-blind study. The present study did not evaluate other variables such as rate of injection administration, needle contact depth, and refrigerant tissue temperature. A study design that included negative controls such as a placebo spray instead of the use of a topical lidocaine spray would provide strong evidence to support the effectiveness of refrigerant.
Further studies with more number of samples, using other materials and techniques to compare their effectiveness as a preinjection anesthetic with that of refrigerant tetrafluorethane, have to be conducted to apply these new methods in clinical practice for painless anesthesia.
| Conclusion|| |
Precooling the injection site using refrigerant tetrafluorethane spray has shown to be effective in eliminating pain before local anesthesia administration in pediatric dental patients when compared with topical anesthetic lidocaine spray. Even though both the topical anesthetic agents were effective in reducing the pain perception, refrigerant tetrafluorethane spray showed significantly higher efficacy as compared to lidocaine topical spray. It had other advantages such as good patient acceptance due to its pleasing taste, decreased waiting time due to quicker and deeper cooling of action, and also decreased children's pain perception both during insertion of needle and during deposition of solution.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
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