Evaluating the knowledge of general dental practitioners regarding local anesthetic injections in pediatric patients

Abstract

Inducing efficient anesthesia makes the dental procedures easier for pediatric patients and the dentist. This study aimed to assess the knowledge of general dental practitioners regarding local anesthetic injections in children. This cross-sectional survey was conducted on 346 general practitioners in Iran. Data were collected by a questionnaire that consisted of three sections: demographic characteristics, general information concerning local anesthesia, and knowledge questions. The Shapiro-Wilk test confirmed the normality of the knowledge score, and independent t-tests and ANOVA were employed to compare the scores. The results showed that general dental practitioners had an average age of 30.1 years (SD = 10.5). Of the participants, 50.6% were female, with an average time since graduation of 62.5 months (SD = 6.7). The mean knowledge score was 8.25 out of 15 (possible range = (0–15)), with a 95% confidence interval of (8.017, 8.483). Participants in retraining courses and those who completed a practical educational anesthesia course after graduation had significantly higher knowledge scores (P < 0.001). The results indicated that just 8.2% of participants were able to correctly apply the aspiration technique, in contrast to 52.9% who correctly identified the maximum recommended dose (MRD) of prilocaine, and 40.2% who accurately knew the height for injection. General dental practitioners exhibited a moderate knowledge (mean knowledge score was 8.25 out of 15) of local anesthetic injections for pediatric patients. However, their knowledge in critical areas such as the MRD of local anesthetics, aspiration techniques, and the correct height for injection was significantly lacking. There is a clear need for general dentists to undergo retraining courses focused on pediatric anesthesia.

Introduction

Local anesthesia by a correct and accurate injection makes the patient comfortable, reduces pain, and increases the child’s cooperation¹. Local anesthetic agents in dentistry briefly disrupt sensory perception, especially pain, which is restricted to a specific region of the body. The desired outcome is accomplished through the administration or injection of a locally effective substance. When selecting a local anesthetic agent and technique for a specific procedure, dentists must consider various factors^2,3.

The administration of local anesthesia requires careful consideration of the variations between pediatric and adult patients, emphasizing (a) the stages of growth and development in children, both physically and psychologically⁴, (b) the management of behavior⁴, (c) anatomical differences that result in decreased depth of injection and easier distribution of the anesthetic agent due to less dense bone^5,6, (d) needle size and length⁵, and (e) special considerations when calculating the maximum recommended dose (MRD) of a local anesthetic agent or a vasoconstrictor⁷.

To ensure the safe and effective administration of local anesthesia, dental practitioners must be knowledgeable about the various types of local anesthesia and their applications. Also, they should consider patient assessment and preparation, understand the pharmacological aspects and drug interactions, and be equipped to handle potential complications and their treatments^8,9. Therefore, dental practitioners must consistently enhance their expertise, skills, and clinical practice, particularly regarding the awareness of adverse effects, contraindications, and drug interactions, to ensure the highest quality of care for every patient¹⁰.

Additionally, although local anesthetics are commonly utilized, a significant number of dental professionals lack knowledge regarding the critical factors involved in administering these agents and calculating appropriate dosages. Kaira and Dabral reported that a significant number of dentists regularly use local anesthesia, often without understanding how to determine the appropriate dosage accurately¹¹. Among malpractice claims concerning adverse anesthesia events in pediatric dentistry, 41% reported local anesthesia overdose cases¹². As a result, to guarantee sufficient knowledge and safety, it is vital to conduct periodic evaluations of contemporary practices.

Various studies have been conducted in the field of local anesthesia in pediatric dentistry^1–8. However, no study has assessed the knowledge of general dentists concerning the application of local anesthesia in pediatric patients in Iran. This is particularly concerning, as these aspects necessitate a deep understanding and specialized knowledge. For instance, the determination of the appropriate dose of local anesthetic agents depends on various factors such as the patient’s age and body weight. Failure to determine the correct dose can lead to inadequate anesthesia or even toxic shock in pediatric patients. Direct and rapid injection of a local anesthetic solution into a blood vessel often results in toxic complications, which can create dangerously high levels in the brain¹³. Therefore, special attention must be directed toward children and individuals with medical conditions when assessing the MRD of local anesthetic agents or vasoconstrictors¹⁴. To the best of our knowledge, this is the first study to assess the knowledge of general dentists about the injections of local anesthetic agents in children. Therefore, the primary objective of this study was to assess general dentists’ knowledge level regarding the administration of local anesthesia in pediatric patients. The secondary objectives were to evaluate potential associations between this knowledge and key demographic/professional factors including age, gender, years since graduation, and practice setting. The null hypothesis was that, there is no significant association between age, gender, average time since graduation, workplace of the dental practice, and the knowledge of general dentists regarding the injection of local anesthetic agents in children.

Materials and methods

Study design

In this cross-sectional study, convenience sampling was used to recruit general dentists from Kerman Province (the central eighth zone of healthcare management in Iran). As the largest province in Iran, Kerman Province is located in the southeast of the country and has a population of over 2 million. The population’s racial composition reflects a high degree of heterogeneity.

Ethical approval

This study was approved by the Ethics Committee of Kerman University of Medical Sciences, with Reg. No. 95,000,389 and the ethics approval code of IR.KMU.REC.1395.687. The Kerman Medical Council provided the required legal permissions for the acquisition. All the participants were assured that their responses would remain strictly confidential and would be used for research purposes only. To protect the participants’ privacy, no personally identifiable information (such as names, contact details, or addresses) was collected in the questionnaire, ensuring complete anonymity. The methods employed in the manuscript adhered to the applicable guidelines and regulations, specifically the Declaration of Helsinki and the Strengthening the Reporting of Observational Studies in Epidemiology¹⁵.

Sample size and study population

The sample size for the knowledge score, calculated from the pilot study’s mean and variance, was determined at 360 participants, accounting for a 95% confidence level, a margin of error of 0.2, and a 20% dropout rate. Eligibility for the study necessitated that individuals engage in a dental practice and hold a degree in dentistry. The criteria for exclusion involved the failure to answer all the questions presented in the questionnaire.

Data collection

During working hours, a dental student intern, with a comprehensive understanding of all research stages, engaged in direct visits to dental clinics. Once the researcher received informed and written consent from the dentists and clarified the benefits of their participation, the questionnaires were subsequently presented to the dental professionals. When the participants filled out the questionnaire, they submitted it to the researcher, who was available to answer the participants’ questions and to provide further details about the research process.

No standard questionnaire was available in Persian to assess the level of knowledge of general dental practitioners about the injection of local anaesthetic agents in paediatric populations. The researchers developed a questionnaire based on the insights of a panel of experts, specifically professors from pertinent educational fields, while following established guidelines for designing questionnaires in knowledge research^16,17. The questionnaire was designed by two experts in pediatric dentistry and one expert in statistics. The questionnaire’s validity was confirmed by submitting the questionnaire to 9 pediatric dentists and maxillofacial surgeons of the Kerman Faculty of Dentistry. Finally, the questions’ level of comprehensibility was discussed. Necessary changes were made in the design of the questionnaire.

The final questionnaire consisted of three parts: the first part contained demographic characteristics (age, gender, and time since graduation); the second part included 7 questions on general information concerning local anesthesia, the analysis of educational methods, and the willingness to participate in teaching activities. Questions number 1 to 7 and their response choices were detailed as follows:

Question #1 (Do you provide care for patients younger than 12 at your workplace? Yes/No).

Question #2 (Which anesthetic agents are available in your workplace setting? Lidocaine/Prilocaine/Bupivacaine/Mepivacaine/Articaine/others).

Question #3 (How did your academic experience equip you with the skills to apply local anesthesia? Human training model/Animal training model/Classmate/Patient).

Question #4 (Did you undertake a hands-on training program in local anesthesia after your graduation? Yes/No).

Question #5 (Have you engaged in a retraining educational program aimed at updating your skills in the administration of local anesthesia? Yes/No).

Question #6 (Would you be interested in participating in an educational course that focuses on the retraining of local anesthesia methods? Yes/No/I have no opinion).

Question #7 (Do you think it is essential to update the knowledge concerning local anesthetic procedures? Yes/No/I have no opinion).

The third part of the questionnaire included knowledge questions (questions #8 to #18) (Table 1). The answers to these questions are presented in Table 2 in bold format. These questions had a total of 16 points (one point for each correct option and zero for the wrong option).

Table 1.

Questions assessing dentists’ knowledge of local anesthesia in children and the accurate responses.

Knowledge Questions	Choices
Q8: In what situations is the technique of aspiration applied?	All injection techniques Block injection techniques None of the injection techniques
Q9: What is the MRD (mg/kg) of 2% lidocaine with epinephrine 1:100,000 for children under 12?	2.4 4.4 6.4 8.4
Q10: What is the MRD (mg/kg) of 4% prilocaine without epinephrine for children under 12?	4 5 6 7
Q11: Which anesthesia techniques do you use for extracting the mandibular first primary molar in a child aged 5?	IANB LNB LBNB BI
Q12: Which anesthesia techniques do you use for extracting the mandibular second primary molar in a child aged 8?	IANB LNB LBNB BI
Q13: Which anesthesia techniques do you use for extracting the mandibular first permanent molar in a child aged 8?	IANB LNB LBNB BI
Q14: Which anesthesia techniques do you use for the pulpectomy of (with the use of rubber dam) maxillary first primary molar in a child aged 5?	PSANB BI PI IONB
Q15: Which anesthesia techniques do you use for extracting the maxillary second primary molar in a child aged 7?	IANB BI PI IONB
Q16: Which anesthesia techniques do you use for extracting the maxillary second primary molar in a child aged 12?	IANB BI PI IONB
Q17: What is the appropriate height for the IANB injection in a child aged 6?	1 cm above the occlusal plane at or slightly above the occlusal plane 1.5 cm above the occlusal plane
Q18: What is the appropriate height for re-injection after the IANB fails in a child aged 6?	at a level lower than that of the first injection at a level higher than that of the first injection at the same level of the first injection

Maximum Recommended Dose (MRD), Inferior Alveolar Nerve Block (IANB), Lingual Nerve Block (LNB), Long Buccal Injection (LBI), Buccal Infiltration (BI), Long Buccal Nerve Block, Palatal Infiltration (PI), Posterior Superior Alveolar Nerve Block (PSANB), Infraorbital Nerve Block (IONB).

The bolded terms in the table represent the correct answers to the questions.

Table 2.

Knowledge levels of participants regarding local anesthesia in children by demographic and educational factors.

Group		Frequency of Participants	Awareness Level (Mean (SD)	p.value
		Count (Percentage)	Mean (SD)
Gender	Male	175 (50.6%)	8.31 (2.184)	0.705
	Female	171 (49.4%)	8.05 (2.221)
Treatment of patients under 12	Yes	240 (69.4%)	8.96 (2.346)	< 0.001
	No	106 (30.6%)	7.84 (2.050)
Educational techniques used for local anesthesia in academic settings	Training models	30 (8.7%)	7.90 (2.325)	0.585
	Classmate	124 (35.8%)	7.44 (1.840)
	Patients	100 (28.9%)	8.91 (2.408)
	More than one method	87 (25.1%)	8.41 (2.009)
Participation in retraining anesthesia courses	Yes	248 (71.7%)	8.39 (2.238)	< 0.001
	No	98 (28.3%)	7.66 (2.030)
Completion of educational and practical anesthesia courses after graduation	Yes	232 (67.1%)	8.48 (2.245)	< 0.001
	No	114 (32.9%)	7.58 (1.991)

Notably, some questions had more than one correct answer; thus, one point was considered for each correct choice, and no point was assigned to wrong choices. In these questions, if even one correct choice was selected, that question was awarded a point. Finally, all the correctly selected choices were given a score of one, and these scores were added together. Questions #8 to #12 and #17 to #18 had one correct answer, questions #13, #14, and #16 had two correct answers, and question #15 had three correct answers. Answers were considered correct only when the participants selected all three correct options. The multiple answers to questions #13 to #16 are presented in Table 2 in the bold format.

The content validity index (CVI) and content validity rate (CVR) were measured at 0.81 and 0.83 for the knowledge questions, 0.85 and 0.80 for the other questions, and 0.82 and 0.0.80 for the total questionnaire, respectively. Due to the favourable CVI (> 0.78) and CVR (> 0.75) of the questionnaire, it was submitted to 20 dentists to examine its reliability. Moreover, all Cronbach’s alpha coefficients exceeded 0.7: 0.72 for the knowledge questions, 0.81 for the other questions, and 0.88 for the total questionnaire. The questions exhibited a strong internal correlation, confirming the reliability of the questionnaire.

Data analysis

Data were analyzed using SPSS 25 (IBM Corp., Armonk, NY, USA). The results were presented as means and standard deviations for the knowledge variable and the percentage of correct responses to knowledge questions. The Shapiro-Wilk test confirmed the normality of the knowledge score, and independent t-tests and ANOVA were employed to compare the scores.

Results

The study included 360 dentists. Fourteen questionnaires were excluded from analysis because they were incomplete, and the final analysis comprised 346 valid questionnaires (response rate = 96%). Of the participants, 50.6% were female, with an average age of 30.1 years (SD = 10.5). The average time since graduation was 62.5 months (SD = 6.7).

The mean knowledge score of 8.25 (95% CI: 8.017–8.483) on a 0–15 scale suggested a moderate level of knowledge among participants. The results showed no significant differences in knowledge scores based on gender or the educational techniques used for local anesthesia in academic settings. However, those who treated children had significantly higher knowledge scores (P < 0.001). Additionally, participants in retraining courses and those who completed a practical educational anesthesia course after graduation also had significantly higher knowledge scores (P < 0.001) (Table 2).

Significant disparities in knowledge were observed in the assessment of dentists’ responses to specialized questions regarding local anesthetic agent injections. Alarmingly, only 8.2% of participants provided correct answers about the aspiration technique, highlighting a critical knowledge gap in this fundamental safety practice. Similarly, awareness about the maximum recommended dose (MRD) of prilocaine was limited, with just 52.9% providing the correct answer, while fewer than half (40.2%) were aware of the appropriate injection height. Even fewer dentists (25.4%) provided a correct answer about re-anesthesia height, underscoring widespread uncertainty in these key clinical parameters (Fig. 1).

Fig. 1.

Frequencies of correct and incorrect responses by dentists to local anesthesia in children. Maximum Recommended Dose (MRD), Inferior Alveolar Nerve Block (IANB), *Primary First Molar, **Primary Second Molar.

Regarding anesthetic agents, the vast majority (98.8%) relied on lidocaine, whereas the use of other agents was rare: only 3.4% used bupivacaine, 0.4% used mepivacaine, and 14.2% used articaine. prilocaine, despite its relevance to MRD questions, was used by just 7.1% of participants. Equally concerning was the neglect of aspiration: a mere 4.8% performed it consistently, while 32.1% omitted it entirely—a troubling finding given its role in preventing systemic toxicity (Fig. 1).

Concerning the willingness to participate in retraining programs, 157 participants (45.4%) expressed their willingness, while 117 (33.8%) responded negatively, and 72 (20.8%) had no opinion. Finally, regarding the willingness to update information, 227 participants (65.6%) expressed their willingness, while 44 (12.7%) responded negatively, and 75 (21.7%) had no opinion.

Discussion

This study revealed a moderate level of knowledge among general dentists about local anesthetic injections for pediatric patients. A significant number of general dental practitioners had a low level of knowledge about the MRD of local anesthetics, the technique of aspiration, the appropriate height for administering IANB, and the correct height for IANB in instances of failure. The results highlighted that a significant proportion of participants were unwilling to engage in retraining courses, and a large number expressed a lack of interest in updating their skills related to local anesthesia. Although a significant number of dentists have completed retraining courses in local anesthesia, their knowledge evaluations have not yielded satisfactory results.

Given the limited research available in this area and the uniqueness of this study as the first study to be carried out in the central eighth zone of healthcare management in Iran, no studies are available in Iran to which these findings can be compared.

MRD knowledge

In this study, general dental practitioners exhibited a poor level of knowledge regarding the MRD of local anesthetics. Collectively, these findings revealed significant knowledge deficits, particularly in aspiration techniques, MRD calculations, and injection protocols, which could compromise patient safety and procedural efficacy. Determining the MRD of any drug, particularly for local anesthetics, is a critical first step in the medication prescribing process. Systemic toxicity from local anesthetics may arise when the MRD of local anesthetic is exceeded, which can happen due to an accidental intravascular injection or through multiple injections¹⁸. Administering local anesthetics provokes a biphasic reaction in the central nervous system. The usual outcome of an overdose is the onset of generalized tonic-clonic convulsions¹⁹. Early subjective symptoms indicative of toxicity primarily involves the central nervous system, characterized by dizziness, confusion, and anxiety, which might be followed by drowsiness, tinnitus, diplopia, tingling, or circumoral numbness. The occurrence of respiratory arrest and loss of consciousness may also take place²⁰. Moreover, the cardiovascular system responds to the toxic effects of local anesthetic agents with a biphasic pattern. In the first phase, the stimulation of the cardiovascular system leads to an increase in blood pressure and heart rate. As anesthetic plasma concentrations increase, vasodilation occurs, leading to myocardial depression and a reduction in blood pressure, possibly resulting in cardiac arrest and bradycardia². Effective prevention of local anesthetic toxicity relies on the application of careful injection techniques, ongoing patient evaluation, and a detailed knowledge of the MRD based on the patient’s weight². Given the critical nature of this matter, it is essential to prominently display the MRD for each anesthetic agent on the packaging of local anesthetic cartridges, ensuring that dentists are alerted to this significant concern. Each local anesthetic package includes a crucial document known as an information leaflet, which provides essential details regarding the anesthetic solution, including dosage guidelines, safety warnings, precautionary measures, and instructions for proper care and handling. All the practitioners involved in the administration or management of local anesthetics ought to periodically review this leaflet²¹.

The low level of dentists’ knowledge in this study regarding local anesthesia administration may stem from the following factors: insufficient practical and theoretical training during dental education, failure to update knowledge after graduation, reliance on personal experience rather than evidence-based protocols, limited access to reliable resources (particularly in local languages), lack of standardized guidelines in clinical settings, and underestimation of potential complications from improper injection techniques. These challenges highlight the urgent need to reform dental curricula, mandate continuing education programs, develop national clinical guidelines, and promote a culture of lifelong learning through webinars and periodic assessments to enhance the safety and efficacy of local anesthesia in clinical practice.

Increased morbidities and health complications resulting from local anesthetic overdoses have been observed in pediatric populations, suggesting that these anesthetics exhibit greater toxicity in children compared to adults²¹. Morbidity and mortality associated with local anesthetic overdose are alarmingly high among children, which supports the hypothesis that local anesthetics are more toxic to this age group than to adults^22,23.

Aspiration technique

In the present study, 8.4% of dentists performed aspiration in all injections. These results show that dentists should be seriously informed about the use of aspiration. The aspiration technique holds significant importance for both adults and particularly for children, as neglecting these methods may lead to toxic effects and life-threatening conditions. The incorporation of self-aspirating dental syringes should be a key focus in retraining courses, particularly for those treating young patients. The use of a self-aspirating dental syringe permits easy performance of multiple aspirations throughout local anesthetic agent deposition. Employing a self-aspirating dental syringe allows for the efficient conduct of multiple aspirations while delivering local anesthetic²¹. Aspiration prior to injections significantly decreases the risk of intravascular injection, while a methodical and slow injection approach minimizes both tissue distortion and the associated discomfort²⁴. Therefore, retraining courses must focus on educating general dentists about the proper application of the aspiration technique.

IANB technique

Although the success rates for IANB in cooperative children are generally between 90% and 95%²¹, the general dental practitioners participating in this study exhibited a poor level of knowledge regarding the appropriate height for administering IANB and the correct height for IANB in instances of failure. The significance of the appropriate height of the IANB injection site in pediatric patients may not have been adequately highlighted in educational settings. Consequently, in the case of this technique’s failure, the training provided was insufficient for achieving the desired level of anesthesia. The leading reason for the ineffectiveness of local anesthesia is attributed to improper needle placement. Furthermore, technical mistakes that involve positioning the needle too high, too low, superficially, or intravascularly contribute to the failure of achieving successful nerve blocks²⁵. Administering local anesthetic repeatedly in children due to ineffective IANB can be challenging, frequently causing negative behavioral outcomes and the possibility of exceeding the MRD. Familiarity with the gross and neuroanatomical features of the head and neck is essential for the effective placement of anesthetic solutions. This will significantly lower the chances of complications, including hematoma, trismus, transient facial paralysis (facial nerve anesthesia), and intravascular injection²¹.

We found a significant relationship between dentists’ knowledge of the differences in local anesthetic injection in children and adults and their participation in practical courses and retraining programs. Concerning this need, Tadin et al. also suggested that it would be helpful for general dental practitioners to participate in continuing dental education programs⁸. Also, Bhanushali et al. found that nearly 40% of general dental practitioners feel a great need for comprehensive continuing educational courses to update their knowledge regarding newer local anesthetic techniques²⁶. Therefore, it can be suggested that courses improve the abilities and knowledge of dentists in different ways.

Our data indicated a significant relationship between dentists’ knowledge of the differences in local anesthetic injection in children and adults and the method of local anesthesia training. The highest average score belonged to those trained to inject local anesthesia into patients or with a combination of existing methods. Teaching with models and classmates was in the next ranks. Although similar research in this field was not found, such a result is quite logical. Training on real patients could improve the knowledge and skills of dentists. One of the available methods of combined training is the same training on patients, which can increase the weight of this method. According to Knipfer et al., it is essential to maintain anesthesia education and guidance during clinical rotations and with actual patients, since training on educational models does not effectively prepare students for practical situations²⁷.

Our study specifically investigated the application of local anesthetics by general dental practitioners in children. Also, attention should be directed towards the fact that various components of children’s diagnosis and treatment by general dental practitioners, such as behavior management techniques, pulp treatments (including primary and permanent teeth), and restorative treatments, should be thoroughly investigated.

Limitations

This study was performed in a specific region of the country, identified as the central eighth zone of healthcare management in Iran, suggesting that any generalization of the results to all general dental practitioners should be approached with caution. The study relied on a self-report questionnaire as the primary data collection tool, which may have caused response bias. Consequently, the findings could be influenced by participants’ subjective perspectives, potentially limiting the objectivity of the conclusions. While this study provides the first comprehensive assessment of Iranian dentists’ knowledge regarding local anesthesia administration in pediatric patients, the absence of comparable national studies limits direct contextual comparisons.

Recommendation

Given that no comparable research exists, researchers should consider conducting similar studies in different communities. Future investigations can implement the pre-test-post-test design to evaluate general dentists’ knowledge improvements. This process includes presenting a questionnaire to a group of dentists before participating in practical courses, followed by a comparison of the findings after practical courses.

Conclusion

This study highlights that the level of knowledge among general dental practitioners regarding local anesthetic injections for pediatric patients is moderate. A significant number of general dental practitioners had a low level of knowledge about the MRD of local anesthetics, the technique of aspiration, the appropriate height for administering IANB, and the correct height for IANB in instances of failure. These findings point to the urgent requirement for changes in educational structures, proposing the introduction of mandatory training sessions alongside longer and more frequent clinical placements in pediatric dental local anesthesia.

Author contributions

ZS, and F.JM, Supervision, Conceptualization. AH, FJM, and AM: Methodology, Data curation, Writing, Editing. FJM: Visualization, Validation. MR and SJ: Designed the research and prepared the figures and tables. All authors reviewed the manuscript.

Funding

NA.

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Competing interests

The authors declare no competing interests.

Consent for publication

Not applicable.

Ethical approval

This study was approved by the Ethics Committee of Kerman University of Medical Science, with Reg. No. 95000389. The Ethics Approval Code is IR.KMU.REC.1395.687.