Knowledge and attitudes of Croatian Dentists Regarding Antibiotic Prescription in Endodontics: A Cross-sectional Questionnaire-based Study.

OBJECTIVES: To assess dentists' level of knowledge and practice concerning antibiotic usage in endodontics using the European Society of Endodontology position statement as a reference.
MATERIALS AND METHODS: A cross-sectional study was conducted in the form of an electronic questionnaire consisting of 23 questions, including dentists' demographic and professional characteristics, attitudes as well as experiences regarding antibiotics in endodontics. Data were evaluated by the Mann-Whitney test or the Kruskal Wallis 1-way ANOVA, α = 5%.
RESULTS: The overall mean self-reported knowledge of antibiotics usage in endodontics was 11.7±2.5 points, out of a maximum possible score of 23. The factors associated with a higher knowledge were: age (P≤0.001), clinical experience (P≤0.001), specialist training (P=0.008), and adherence to the guidance on the use of systemic antibiotics in endodontics (P=0.006). Dentists who specialized in endodontics (16.1±2.2) achieved higher levels of knowledge.
CONCLUSION: Knowledge on antibiotic usage in endodontics among dentists in Croatia is insufficient. There is a need for continuing education on the use of antibiotics among general dentists.

Introduction

Most endodontic infections, likewise other odontogenic infections, have a polymicrobial origin, involving gram-positive, gram-negative, and strict or facultative anaerobic bacteria (). Most endodontic infections are located within the tooth and can be solved by root canal treatment, drainage, or tooth extraction, without the need for local or systemic antibiotics (). Antibiotics should be used as an adjunct in treating apical periodontitis and only in cases of acute apical abscess with systematic involvement, when an infection is fast progressing, or in immunocompromised patients (-). In healthy patients, bacteremia caused by root canal treatment is transient and does not cause complications (). The use of antibiotics is contraindicated in irreversible pulpitis, pulp necrosis, chronic apical periodontitis and localized apical periodontitis (). Previous studies have reported that antibiotics do not reduce the pain or swelling arising in non-vital symptomatic teeth in the absence of systematic involvement (, ). On the other hand, the patients with life-threatening conditions such as swelling of the floor of the mouth or breathing difficulties should be hospitalized and treated by administering intravenous antibiotics ().

Since the microbial samples are not routinely taken from infected root canals, antibiotics are usually prescribed empirically, which consequently leads to their over-prescription (). Antibiotic overuse and prescription of inappropriate antibiotics (misuse) have been the leading cause of increased microbial resistance (). It has been estimated that over 25, 0000 antibiotic-resistant infection cases per year are being diagnosed in the United States, of which 23,000 are lethal (). Another aspect in the context of health-care consequences of antibacterial resistance includes health complications requiring higher treatment needs and hospital costs (, ). Furthermore, overuse and misuse of antibiotics can increase the risk of developing potentially fatal side effects or anaphylactic reactions (, , ).

Although dentists are accountable for approximately 10% of the overall antibiotic prescriptions, their influence on the development of resistant bacterial species is not negligible (). Also, the problem of increased antibiotic prescribing has arisen in recent years (). Another critical issue is the use of antibiotic prophylaxis in medically compromised patients undergoing endodontic therapy. Although there are many controversies in the literature regarding this issue, antibiotic prophylaxis is still necessary in cases when the benefits have been clearly demonstrated (, ). Therefore, in 2018, the European Society of Endodontology (ESE) issued detailed guidelines on antibiotic prescribing (). However, despite the existing guidelines, the validity of antibiotic prescribing in practice, as well as the level of adherence to the current recommendations remains unclear (, ).

The purpose of this study was to investigate the knowledge and attitudes of Croatian dentists regarding antibiotic prescription practice in endodontics by relying on the ESE recommendations.

Material and methods

This online cross-sectional study was conducted between January and March 2020 among dentists working in Croatia. The study was conducted in full accordance with the ethical principles, including the World Medical Association Declaration of Helsinki (version 2008), and was approved by the Ethics Committee of the University of Split School of Medicine, Split, Croatia (No: 003-08/20-03/0005).

An online questionnaire consisting of three parts was designed specifically for this study. The first part included dentists’ socio-demographic and general characteristics such as age, gender, years of experience, education level, clinical setting, specialization and the number of patients treated a day. The second part of the questionnaire comprised ten multiple-choice questions (MCQs) concerning the use of antibiotics in endodontics. These questions referred to the usage of antibiotics in endodontics by the European Society of Endodontology (). Five items were conventional MCQs with only one correct answer, while other five items were with several correct answers. Each correct answer was scored with one point, while incorrect answers were scored with zero. The total knowledge score was calculated as the sum of all correct answers, with a maximum overall knowledge score of 23 points. Overall knowledge per participant was categorized, using the Bloom’s cut-off point, with “good” representing 80 to 100% (16.8–23 points), “moderate” if the score was from 60 to 79% (12.6–16.7 points), and “poor” if the overall score was less than 60% of the maximum score (≤12.5 points) (). The third part of the questionnaire included questions about participant's personal experiences, attitudes, and self-assessed knowledge about the use of antibiotics in endodontics.

Firstly, the experts in different dental fields (three endodontists and one pharmacologist) reviewed the draft version of the questionnaire and agreed on the final suitability. A pilot study including 100 dentists was conducted as part of a graduation thesis at the Study of Dental Medicine, University of Split School of Medicine. The data obtained from the pilot study were not included in the analyses. The final questionnaire was adapted based on the data obtained from the pilot study, and it was sent to ten dentists for feedback, who reported having no difficulty in completing the test. The online questionnaire was generated using a Google Docs form and was sent to the legal administrative staff of the Croatian Dental Chamber (CDC) for approval. The CDC staff then shared the link to the questionnaire to all dentists on their official mailing list.

Participation in the study was voluntary, anonymous, and without compensation. All participants were informed about the rationale and the aim of the study. The online form first displayed information about the scope of the study that dentists had to go through before moving forward to the questionnaire. Completing the questionnaire was considered to be consent for participation. In order to be included in the study, dentists had to work in clinical practice with minimum one year experience, and the membership in the CDC.

The study was reported to be in accordance with the STROBE reporting checklist ().

The minimum required sample size (n=337) was calculated by considering the total number of dentists who worked in clinical practice (n=2743), a population proportion of 50%, and a 95% confidence interval (). All answers from the online form were automatically imported in an Excel file (Ver. Office 2007, Microsoft Corporation, Redmond, WA, USA) and were then coded appropriately for the analyses. The results were first analyzed using descriptive statistics. The Kolmogorov-Smirnov test evaluated compliance with the normal distribution of the dependent variable. Means and standard deviations were calculated for quantitative variables, while percentages and absolute numbers were used for presenting qualitative variables. Statistical analyses were conducted using the Mann-Whitney test or the Kruskal Wallis 1-way ANOVA. To account for possible confounding, general regression analysis was used to determine a relationship between selected independent variables (age, gender, working experience, specialist training, number of patients treated a day, attending a lecture regarding antibiotics in endodontics and knowledge regarding guidance on the use of systemic antibiotics in endodontics) with the knowledge score (dependent variable). The level was set at 5%. All statistical analyses were carried out using the IBM SPSS Statistics, version 25 (SPSS, IBM Corp, Armonk, New York, USA).

Results

A total of 657 dentists working in Croatia participated in this study (23.96% response rate). The demographic and professional characteristics of the participants are presented in Table 1. The majority (96.5%) of the participants who responded worked in primary care and most of them were females (71.5%). The mean age (+SD) of the participants was 41.86±11.54 years, with 14.02±10.98 years of working experience.

Table 1

Demographic and professional characteristic of dentists (n=657)

Characteristic		Total n (%)	Knowledge score mean±SD	P-value
Gender	Male	187 (28.5)	11.6±2.5	0.567
	Female	470 (71.5)	11.7±2.5
Age group (years)	25-35	257 (39.1)	12.9±2.4a,b	≤0.001
	36-45	140 (21.3)	11.7±2.6c
	46-55	162 (24.7)	11.1±2.3a,c
	≥55	98 (14.9)	11.3±2.7b
Postgraduate qualification	None	550 (83.7)	11.7±2.5a	0.043
	Master’s degree	71 (10.8)	11.1±2.7a,b
	PhD	26 (3.9)	12.5±3.1b
Specialty	General practitioner	590 (89.8)	11.6±2.5	0.008
	Specialist	67 (10.2)	12.6±2.8
Specialization	Endodontist	7 (1.1)	16.1±2.2a,b,c,d,e,f	0.021
	Oral surgeon	15 (2.3)	12.1±2.2a
	Pediatric dentist	8 (1.2)	12.0±3.3b
	Orthodontist	7 (1.1)	12.1±1.9c
	Prosthodontist	16 (2.4)	12.1±2.9d
	Periodontist	9 (1.4)	11.8±1.1e
	Other	5 (0.8)	13.2±4.9f
Practice setting	Unemployed	19 (2.9)	12.5±3.1	0.003
	Private – primary care	164 (25.0)	11.5±2.1a
	Semiprivate and health center – primary care	431 (65.6)	11.5±2.5b
	Government – secondary and tertiary care	43 (6.5)	13.2±3.2a,b
Working experience (years)	1-5	309 (47.0)	12.1±2.5a,b	≤0.001
	6-10	167 (25.4)	11.3±2.6a
	11-20	123 (18.7)	11.1±2.3b
	≥21	58 (8.8)	11.6±3.1
Number of patients seen in a workday	0-5	55 (8.4)	12.7±2.8a,b,c	≤0.001
	6-10	329 (50.1)	11.9±2.5a,d
	11-20	51 (7.8)	11.3±2.5b,d
	21-30	222 (33.8)	11.7±2.5c
Data are presented as whole numbers and percentages or mean ± SD. *Statistical significance was tested by the Mann-Whitney test or Kruskal Wallis 1-way ANOVA. The same superscript lower letter indicated a statistical difference between groups based on post hoc test. Statistical significance was set to p<0.05. Abbreviation: SD – standard deviation.

The overall mean knowledge score regarding antibiotics use in endodontics was 11.7±2.5 points. There were no significant differences between genders (P=0.567), with mean values for male and female dentists being 11.6±2.5 and 11.7±2.5, respectively. There was a significant difference (P<0.001) in knowledge scores between specialists (12.6±2.8) and general practitioners (11.6 ± 2.5), with endodontic specialists scoring the highest (P=0.021). There was a significant difference in knowledge scores (P≤0.001), suggesting a slight decrease in knowledge regarding years of work experience, with the highest scores observed among participants working from 0 to 5 years (12.1±2.5), compared to those working either from 6 to 10 years (11.3±2.6) or from 11 to 20 years (11.1±2.3).

Table 2 shows the distribution of correct answers to the questions regarding antibiotics use in endodontics. Only 2.0% (n=13) of the surveyed dentists knew that Penicillin VK is a beta-lactam antibiotic, which is the first line of antibiotics chosen as adjunct therapeutic agents in endodontic infection in a healthy patient with no medical allergies. Also, only 17.2% (n=113) of them gave the same answers for Amoxicillin. Most of the dentists answered (94.5%, n=621) that endodontic surgery is a procedure that requires administration of prophylactic antibiotics to prevent infective endocarditis. In contrast, only 27.1% (n=178) of them stated that periodontal ligament (intraligamentary) anesthesia requires the same approach.

Table 2

The frequency distribution (%) of dentists' answers to the questions regarding antibiotics use in endodontics

Question	Answer	Total n (%)
When systemic antibiotics are indicated, which antibiotic would you choose for the treatment of an endodontic infection in an adult, healthy patient with no medical allergies?	Tetracyclines	2 (0.3)
	Azithromycin	0 (0)
	Erythromycin	2 (0.3)
	Clindamycin	38 (5.8)
	Amoxicillin with clavulanic acid	481 (73.2)
	Cephalosporins	1 (0.2)
	Metronidazole	7 (1.1)
	Clarithromycin	0 (0)
	Penicillin V	13 (2.0)
	Amoxicillin	113 (17.2)
	Ciprofloxacin	0 (0)
When systemic antibiotics are indicated, which antibiotic would you choose for the treatment of an endodontic infection in an adult, healthy patient with an allergy to Penicillin?	Tetracyclines	3 (0.5)
	Azithromycin	11 (1.7)
	Erythromycin	47 (7.2)
	Clindamycin	547 (83.3)
	Amoxicillin with clavulanic acid	2 (0.3)
	Cephalosporins	26 (4.0)
	Metronidazole	10 (1.5)
	Clarithromycin	4 (0.6)
	Penicillin V	0 (0)
	Amoxicillin	2 (0.6)
	Ciprofloxacin	3 (0.5)
For how many days would you prescribe antibiotics?	3-7 day	209 (31.8)
	5-10 days	191 (29.1)
	Patient need to use all antibiotics from the prescribed package	257 (39.1)
If prescribed 1st line antibiotic is not practical in 48–72 h, what would you do?	Prescribe an additional antibiotic – Metronidazole	389 (79.9)
	Refer to specialist	35 (5.3)
	Extraction	3 (0.6)
	Other	70 (14.4)
In which of the following situations do you consider that antibiotics are indicated?	Symptomatic irreversible pulpitis	1 (0.2)
	Pulp necrosis	3 (0.5)
	Symptomatic apical periodontitis	5 (0.8)
	Acute apical abscess with systemic involvement	554 (82.8)
	Acute apical abscess without systemic involvement	92 (14.0)
	Chronic apical periodontitis with sinus tract	13 (2.0)
When is antibiotic prophylaxis indicated, in which of the following medical conditions would you prescribe before endodontic surgery?	Impaired immunologic function	455 (69.2)
	Prosthetic joint replacement	380 (57.8)
	Patients whose jawbones are exposed to high‐dose irradiation	265 (40.3)
	Patients receiving intravenous bisphosphonate treatment	186 (28.3)
	Patients with cyanotic congenital heart disease	379 (77.8)
	Patients with noncyanotic congenital heart disease	107 (22.0)
	Patients with high blood pressure	3 (0.4)
	Patients with liver disease	13(1.9)
When is antibiotic prophylaxis indicated, in which of the following dental procedures would you prescribe it?	Supraperiosteal injection	36 (5.5)
	Periodontal ligament (Intraligamentary) injection	178 (27.1)
	An alveolar nerve block injection	64 (9.7)
	Endodontic access opening of teeth with vital pulpal tissues	85 (12.9)
	Endodontic access opening of teeth with necrotic pulpal tissues	16 (2.4)
	Endodontic instrumentation and obturation	170 (25.8)
	Retreatment of root canal filling of an asymptomatic tooth without signs of periapical periodontitis on X-ray	13 (2.7)
	Retreatment of the root canal filling of an asymptomatic tooth with the presence of signs of periapical periodontitis on X-ray	85 (17.5)
	Retreatment of root canal filling of the symptomatic tooth (pain) with the presence of signs of periapical periodontitis on X-ray	203 (41.7)
	Endodontic surgery	621 (94.5)
In an adult, healthy patient with no medical allergies, with irreversible pulpitis, to avoid the occurrence of postoperative complications (pain, swelling), do you consider it necessary to prescribe antibiotics before endodontic instrumentation?	No	648 (98.8)
	Yes	9 (1.3)
In an adult, healthy patient with no medical allergies, with pulp necrosis, to avoid the occurrence of postoperative complications (pain, swelling), do you consider it necessary to prescribe antibiotics before endodontic instrumentation?	No	644 (98.0)
	Yes	13 (2.0)
In an adult, healthy patient with no medical allergies, with chronic apical periodontitis, to avoid the occurrence of postoperative complications (pain, swelling), do you consider it necessary to prescribe antibiotics before endodontic instrumentation?	No	609 (92.7)
	Yes	48 (7.3)
Data are presented as whole numbers and percentages. Correct answers are italicized.

The answers regarding antibiotic prescription in endodontics are presented in Table 3. A higher level of knowledge was observed in dentists who reported being informed about guidelines on the use of systemic antibiotics in endodontics (p=0.006). More than half of the participating dentists (54.1%) claimed that their knowledge regarding the use of antibiotics in endodontics was good and very good.

Table 3

Attitudes of dentists toward antibiotic prescribing in endodontics

Characteristic		Total n (%)	Knowledge score mean± SD	P-value
Attending at least one lecture relating to the use of antibiotics in endodontics during the last three years	No	334 (50.8)	11.5±2.4	0.074
	Yes	323 (49.2)	11.9±2.6
Informed about guidance on the use of systemic antibiotics in endodontics	No	114 (21.9)	11.1±2.3	0.006
	Yes	513 (78.1)	11.8±2.6
Guidelines followed for prescribing regiments among suspectable patient	Croatian Endodontic Society	367 (55.9)	11.5±2.5a,b	≤0.001
	European Society of Endodontology	74 (11.3)	12.6±2.6a,c
	British Society of Cardiology	13 (2.0)	12.5±2.8
	American Cardiac Association	49 (7.5)	12.7±2.5b,d
	Others	154 (23.4)	11.1±2.3c,d
How would you rate your knowledge regarding the usage of antibiotics in endodontics?	Very good	33 (5.0)	12.0±2.8	0.966
	Good	341 (49.1)	11.7±2.6
	Fair	271 (41.2)	11.6±2.3
	Poor	12 (1.8)	12.2±2.7
After root canal therapy, have you ever prescribed antibiotics for postoperative pain?	No	573 (87.2))	11.7±2.5	0.168
	Yes	84 (12.7)	11.3±2.5
Have you ever prescribed antibiotics in endodontics to achieve a placebo effect?	No	530 (80.7)	11.7±2.5	0.873
	Yes	127 (19.3)	11.7±2.4
Do you prescribe a leading (double) dose of antibiotics for an endodontic infection?	No	447 (68.0)	11.6±2.5	0.108
	Yes	210 (32.0)	11.9±2.6
Number of prescribed systemic antibiotic for prophylaxis during last year	None	126 (19.2)	11.7±2.5	0.627
	Once	190 (28.9)	11.5±2.3
	More than once	341 (51.9)	11.7±2.7
How often do you doubt justification when prescribing antibiotics in case of endodontic infections?	Always	3 (0.5)	11.9±2.8	0.940
	Very frequently	22 (3.3)	11.6±2.0
	Occasionally	228 (34.7)	11.6±2.4
	Rarely	286 (43.5)	11.7±2.6
	Very rarely	118 (18.0)	11.5±2.7
What are your "knowledge gaps" regarding the usage of antibiotics in endodontics?	Antibiotic – drug interactions	260 (39.6)	11.9±2.6	0.519
	Types of antibiotics recommended dosages and duration	35 (5.3)	11.4±2.5
	Prescription of antibiotics to children, pregnant and lactating women	212 (32.3)	11.6±2.5
	Indications for antibiotics during endodontic therapies	74 (11.3)	11.4±2.3
	Other	76 (11.6)	11.3±2.5
Data are presented as whole numbers and percentages or mean ± SD. *Statistical significance was tested by the Mann-Whitney test or Kruskal Wallis 1-way ANOVA. The same superscript lower letter indicated a statistical difference between groups based on post hoc test. Statistical significance was set to p<0.05. Abbreviation: SD – standard deviation.

The association of the dentists’ knowledge about antibiotics use and their demographic data as possible predictors are presented in Figure 1. Knowledge was shown to be associated with dentists' age (β=-0.539, SE=0.187, P=0.004), specialization (β=1.364, SE=0.324, P≤0.001), number of patients treated daily (β=-0.363, SE=0.130, P=0.005), and awareness about the available guidance on the use of systemic antibiotics in endodontics (β=0.609, SE=0.248, P=0.014).

Figure 1

Multiple linear regression analysis. Significant dependence of measured knowledge with participant demographic data and attitudes toward the usage of antibiotics in endodontics as possible predictors.

Discussion

This cross-sectional questionnaires-based study found insufficient knowledge regarding antibiotic prescription in endodontics among Croatian dentists. Although most participants reported being familiar with some of the available guidelines on the use of antibiotics, the overall score was only 50% of the overall maximum score. Similar results suggesting insufficient knowledge, practice, and attitudes regarding antibiotics use were reported among dentists and dental students in Italy, Turkey, Saudi Arabia, and Iran (-).

Interestingly, the youngest respondents with the least clinical experience (one to five years) demonstrated the highest level of knowledge, which is in line with the recommendations from the European Society of Endodontology (). This may be explained by the fact that they most recently completed their formal university education. Also, endodontics specialists showed better knowledge than general practitioners and specialists in other fields of dentistry, which can be explained by their specific training in the field of interest.

Although the ESE guidelines recommended Penicillin V and Amoxicillin as the first-line antibiotics for the treatment of endodontic infections in cases of no allergy to penicillin, only 2% and 17.2% of the dentists answered correctly (, ). Amoxicillin with clavulanic acid was reported to be the most frequently prescribed antibiotic. Similar reports were observed in studies involving dentists from Saudi Arabia and Turkey. However, they are also in line with the latest studies conducted in Croatia (, , , -). Likewise, Lithuanian, UK, and Australian dentists considered Amoxicillin the most preferred antibiotic during endodontic treatment (-). However, in a study involving dentists from Sweden, the most frequently prescribed antibiotic was penicillin VK ().

According to the ESE guidelines, in case of penicillin allergy, possible alternatives include Clindamycin, Clarithromycin, or Azithromycin (). In this study, Clindamycin was most often (83.3%) reported alternative to Penicillin. Clarithromycin or Azithromycin were selected as substitutes to Penicillin very rarely, with the frequency of answers being 0.6%, and 1.7%, respectively. Clindamycin was also the antibiotic of choice in cases of penicillin allergies among dentists in Saudi Arabia, Serbia, Turkey, and Spain (, , , ).

If clinical signs and symptoms do not improve in 2-3 days of taking the first-line antibiotics, it is recommended to use a supplementary one (, ). In Europe, Metronidazole is the antibiotic of choice when penicillin alone is not effective, because of its effectiveness against anaerobic bacteria. Therefore, it is usually combined with Penicillin, and more than half of the dentists in this study agreed with this recommendation ().

Furthermore, because most oral infections have a rapid onset, it is necessary to establish minimum inhibitory antibiotic concentration fast (). Thus, a loading dose (first double dose) is recommended (, ). This recommendation of the European Endodontic Society was known to around one-third of the dentist from this study.

Acute oral infections are most often resolved within 3-7 days (). In most cases, antibiotics should be prescribed only for the period in which improvement of symptoms is achieved and should not be continued 1-2 days after withdrawal of clinical signs of infection (). Also, a shorter use of antibiotics lowers the risk of the development of resistant microorganisms (). Almost half of the responders in this study answered that a full, long course of antibiotics should be administrated, with about one-third answering that the duration of the therapy should be three to seven days. The results from similar studies conducted in Brazil, Saudi Arabia, and Spain reported the average time of antibiotic usage being seven days, which is considered to be unnecessarily long (, , ).

Regarding the indications for antibiotic prescribing, most participants (84%) responded that the indication for antibiotic therapy was an acute apical abscess with the existence of systemic signs of infection. A smaller proportion of participants (14%) reported that an acute apical abscess without systemic symptoms required antibiotic therapy, and only 2% of participants reported one of the remaining responses (symptomatic reversible pulpitis, pulp necrosis, symptomatic apical periodontitis, and chronic apical periodontitis with sinus tract) as an indication for antibiotic administration. In such situations, the use of antibiotics is considered futile, because due to the lack of pulp circulation, antibiotics cannot reach the endodontic space and eliminate bacteria (). These results are comparable to the results of Alonso et al. () where 83.3% of respondents answered that acute apical abscess is an indication for antibiotic therapy. Croatian dentists showed better knowledge compared to studies of Alatas et al. () and Whitten et al. () where only 31.2%, and almost 50%, of respondents, respectively, answered that antibiotics are indicated in acute apical periodontitis with systematic involvement. Although, in relation to the before-mentioned studies, a relatively low percentage of dentists (16%) in this study answered that antibiotics are indicated in cases when treatment could be reduced with non-surgical root canal therapy with analgesics, if necessary, there is still space for improvements in better understanding of antibiotics use (, ).

Nevertheless, antibiotics should be administered in immuno- compromised patients to avoid complications associated with endodontic-associated bacteremia. Particularly vulnerable groups of patients are patients with localized congenital heart defects, patients with impaired immunologic function, patients with prosthetic joint replacement within three months of surgery, patients whose jawbones are exposed to high-dose irradiation, and patients receiving intravenous bisphosphonate treatment (, , ). This study has shown a high percentage of dentists having sufficient knowledge regarding antibiotic prophylaxis administration. A small number of participants considered antibiotic prophylaxis appropriate in patients with non-cyanotic heart defects, for patients with liver disease or high blood pressure. Data on the use of antibiotic prophylaxis from other studies are heterogeneous but they show that clinicians are not always sure whether antibiotic prophylaxis is needed; therefore they use it defensively. On the other hand, certain diagnoses that are clear indications of the need for prophylaxis remain unrecognized, thus putting the patient an increased risk of developing bacteremia (, ). Moreover, almost all dentists in our study considered endodontic surgery an indication for the use of prophylactic antibiotics.

The answers related to the retreatment procedure mostly depended on the symptomatology and the presence of signs of apical periodontitis on X-rays. Thus, the largest number of dentists answered that prophylaxis is necessary for the retreatment of root canals with apical periodontitis, while only 2.7% of dentists considered prophylaxis in the procedure of retreatment of an asymptomatic tooth without signs of apical periodontitis on X-ray.

Certain techniques of local anesthesia in dentistry, such as intraligamentary injection, require antibiotic prophylaxis in patients with the risk of developing infectious endocarditis (). However, in this study, almost one-third of dentists reported the usage of prophylaxis before the application of intraligamentary anesthesia. Findings from the study by Mansour et al. () were even more disturbing bacause only 4, 6% of participants reported that prophylaxis is needed before the intraligamentary anesthesia.

On the other hand, using antibiotic prophylaxis before procedures for which it is not indicated, as reported by some of the dentists in this study, may only contribute to the development of resistant strains of microorganisms. Croatian dentists have shown satisfactory knowledge about the usage of antibiotic prophylaxis when compared with prescription patterns seen in the USA, where 80, 9% of antibiotic prophylaxis prescriptions were found to be unnecessary and in contrast to the available guidelines ().

In addition to all the above-mentioned issues concerning antibiotic prescribing, there is also an issue of prescribing antibiotic therapy to achieve a placebo effect. Bjelovucic et al. () reported that lack of time to perform adequate treatment often leads to over-prescription of antibiotics. In this study, one-fifth of participants answered that they had prescribed antibiotics one or more times, but it was only to achieve the placebo effect. These findings suggest that many practitioners still give in to the patients' pressure rather than to the available guidelines. These are, however, issues caused by multifactorial origins, and might only be well understood through a qualitative approach. Also, almost 40% of dentists considered that they lacked knowledge in the field of drug interactions with antibiotics, with one-third of them feeling insecure when prescribing antibiotics to children or pregnant and lactating women.

Bearing on mind the fact that an inappropriate use of antibiotics and lack of knowledge on their rational use can lead to antibiotic resistance, dental health professionals need to reduce antibiotic prescriptions by following the available up-to-date guidelines. According to a recent systematic review, it is necessary to improve worldwide prescribing habits of antibiotics in the treatment of endodontic infections ().

Since this study was conducted using an online questionnaire, the limitations are common to other questionnaire-based studies, including the problem of the low response rate, the risk of socially desirable responses, and the consistency of responses. These findings thus encourage more rigorous methods in order to stimulate higher participation in future studies, thus allowing better representativeness and generalizability of the results. That in turn, should guide future training on antibiotic use in everyday clinical settings, with specifically tailored regular and up-to-date reports of the best available evidence on antibiotic prescribing to meet the needs of practicing dentists.

Conclusions

Croatian dentists’ level of knowledge regarding antibiotic prescription practice in endodontic is not entirely satisfactory. Younger dentists showed better knowledge; likewise those with specialist training, as well as those familiar with guidelines on the use of systemic antibiotics in endodontics. Specifically tailored educational interventions for dentists, including campaigns and lectures on the appropriate use of antibiotics and prevention of antibiotic resistance, are needed.