Single-Visit Endodontic Therapy and Root Canal Identification Practices among Croatian Dentists: Insights from a National Survey

Abstract

Objective

to analyze a single-visit endodontic treatment together with root canal detection practices in Croatia and investigate their relationship with reported postoperative pain, medication prescription, magnifying devices, rubber dam, radiographical checks before the procedure, cone-beam computed tomography (CBCT) and engine-driven instrumentation.

Materials and Methods

A structured questionnaire was distributed via email to all Croatian dental practitioners, with 819 responses analyzed corresponding to an estimated 27% response rate. Statistical analyses included descriptive analysis and regression modelling.

Results

Among Croatian practitioners, 27.9% frequently performed single-visit endodontic treatments. Male practitioners, practitioners with continuous education and ample experience, endodontic specialists, and those working in polyclinics or academic settings were more likely to adopt this approach. It correlated positively also with the use of advanced diagnostic and treatment tools (e.g., magnification devices, rubber dam, CBCT) and a reduction in antibiotic prescription. However, it was associated with increased reported analgesic prescription and a larger number of reported vertical tooth fractures. Practitioners reported less frequently using single-visit endodontic treatments for multi-rooted teeth and those with associated sinus tracts or periradicular lesions. Furthermore, practitioners more often performing single-visit endodontic treatment rate themselves better in finding additional canals, which is positively influenced by usage of radiography and magnification devices. In addition, continuous education has a positive effect on the root-finding abilities, but it decreases with years of their clinical experience.

Conclusions

Single-visit endodontic treatment practice in Croatia is influenced by practitioner education, experience, and access to advanced equipment. While it offers benefits such as reduced antibiotic prescription, clinical attention and further research is needed to address potentially associated complications such as vertical tooth fractures and reliance on analgesics. Root finding abilities are positively influenced by continuous education. These findings underscore the role of education and resources in optimizing endodontic outcomes.

Introduction

Single-visit endodontic treatment (ET) offers several advantages over conventional multi-visit treatment but may also carry an increased risk of complications (1). The benefits of single-visit treatment include greater patient convenience due to shorter chair time, lower costs resulting from reduced use of dental materials, and a decreased risk of potential microleakage between treatment visits.

Previous research on single-visit endodontic treatments has primarily focused on the reduction of postoperative pain (2–15). Comparison between single-visit and multiple-visit treatments has been made from various perspectives, including timing and frequency (16), treatment outcome evaluation (17–30), and the incidence and intensity of post-endodontic pain (31–37). Additionally, several studies have investigated the criteria on which clinicians base their decision to perform single versus multiple-visits ET (38–40). Systematic reviews have compared these approaches (1, 41–44), with the most recent review (42) concluding that there is currently no evidence to suggest one method is categorically superior to the other—except for “moderate‐certainty evidence of higher proportion of participants reporting pain within one week in single‐visit groups compared to multiple‐visit groups”. The review found no differences in swelling, flare‐up incidence, sinus tract or fistula formation, or analgesic use—though the latter contrasts with findings from and earlier Cochrane review (28). Most outcomes were based on very low to low-certainty evidence, except for the absence of a difference in radiologic failure after at least one year (i.e. periapical radiolucency), and the pain reported within one week, for which the evidence was of a moderate certainty. This study, therefore, aims to contribute to the ongoing comparison between single-visit and multiple-visit ET with additional evidence.

In Croatia, previous research on ETs has examined the referral of problematic endodontically treated teeth to oral surgery (45), the use of antibiotics (46–48), and the overall state of endodontic practice (49). However, this is the first study to investigate single-visit ET practices specifically in Croatia. The primary aim is to analyze the prevalence of single-visit treatments and explore their relationship with reported pain, medication prescriptions, usage of radiographic assessment prior to the procedure, cone-beam computed tomography (CBCT), and engine-driven instrumentation. A secondary objective is to examine root canal detection practices.

Materials and methods

The Ethics Committee of the University of Zagreb approved this study under number 05-PA-24-3/2018.

Questionnaire

The Croatian Chamber of Dental Medicine has, via email, sent a link to the questionnaire to all dental practitioners in Croatia, the number of which is estimated to 3000 by using data from the Croatian Institute of Public Health and the Croatian Health Statistics yearbook for 2022. The responses were then collected in the period from May 2021 to March 2022. The questionnaire is available at https://forms.gle/nmUeQizSoN2U5SNYA.

Participants provided demographic information, including sex (female-F, male-M), years of practice, degree of clinical education (DCE) (DDM – Doctor of Dental Medicine, EndoS – Specialist in Endodontics, EndoR – Resident in Endodontics (a doctor of dental medicine referred to a specialist clinic with the aim of gathering theoretical, practical, professional and scientific knowledge in endodontics within three years, after the expiry of which the specialist exam is taken), Other), clinical settings (HC - Health Center, InConc - Dental Clinic with Concession Contract, Priv - Private Clinic, PrivSA - Private Clinic with a Health Fund Contract, Poly - Dental Polyclinic, SDM - School of Dental Medicine), and continuous education in endodontics taken in the last 5 years. The questionnaire included the following questions on endodontic clinical practices that are relevant for this paper. For almost all questions possible answers were as follows: Never / Very rarely / Rarely / Often / Almost always / Always. The questions that had different answers are specified with their answers:

• How many teeth do you treat per month? (number)

• Do you use an apex locator in your clinical practice?

• Do you use magnification devices in your clinical practice?

• Do you use additional lighting with magnification devices? (Yes / No)

• Do you use radiographs before the instrumentation of root canals?

• Do you use a rubber dam in your endodontic clinical practice?

• Do you perform manual instrumentation of root canals?

• Do you perform engine-driven instrumentation of root canals?

• Do you perform a combination of manual and engine-driven instrumentation of root canals?

• Do you perform final irrigation to remove the smear layer?

• Do you use CBCT in your clinical practice?

• How often do you perform single-visit ET?

• Do you perform pulp amputation procedures on permanent teeth?

• Do your patients report pain between visits or after endodontic treatment?

• Do you prescribe analgesics for endodontic procedures?

• Do you prescribe antibiotics for endodontic procedures?

• Have you observed vertical tooth fractures following your own endodontic procedures?

• How do you perform pulp extirpation? (Vital extirpation, fill in multiple visits/next visit/one visit, Mortal extirpation, fill in multiple visits/next visit/one visit)

• How often do you refer patients for apicoectomies?

• Do you find the second bucco-mesial canal in maxillary molars?

• Do you find a second canal in the distal root in mandibular molars?

• Do you find two canals in mandibular incisors?

• Free comment.

Statistical methods

Analysis was performed using R Project for Statistical Computing (ver. 4.4.1) with the Survey package. Using the specialized Survey package is necessary because in this study the sample size is comparable to the population size, which makes the finite population correction factor not negligible.

The distribution of practitioners by sex, years of practice, and continuous education was examined. Ordinal and logistic regression models were constructed to assess all the factors influencing variables of interest. All regression models were adjusted for sex and years of practice. For all unordered predictor factors, except gender, sum contrast was used, meaning that the variables are contrasted to their mean. For ordered factors, Helmert contrasts were used meaning that variables are contrasted successively to their lower values.

Effects are reported as log odds (LO), with significance codes: 0.001, 0.01, 0.05, 0.1 designated in figures by three, two and one stars respectively. The dot corresponds to the 0.1 significance level. Slopes are designated with a corresponding number of stripes whereas a dotted stripe corresponds to a dot, i.e., to 0.1 significance. Reported are only the effects that were found significant.

Results

General description of respondents

A total of 819 responses were collected, representing a 27% response rate. By excluding 31 respondents who do not perform ETs (3.8%), the analysis focused on 788 respondents engaged in endodontics. Table 1 presents general numbers related to single-visit ET and related endodontic practices, whereas Figure 1 shows general characteristics of endodontic practitioners. Figure 2 presents self-perceived success in finding root canals in permanent teeth frequently exhibiting complex internal morphologies.

Table 1. Characteristics of endodontic practice (population estimate of percentages and related standard errors).

Single-visit ET (all practitioners)
Never	20.1% (0.01)
Very rarely	32.4% (0.01)
Rarely	19.6% (0.01)
Often	20.7% (0.01)
Almost always	4.1% (0.01)
Always	3.1% (0.01)
Single-visit ET (only specialists and residents in endodontics)
Never	3.6% (0.02)
Very rarely	16,1% (0.05)
Rarely	10.7% (0.04)
Often	30.4% (0.06)
Almost always	16.1% (0.05)
Always	23.2% (0.06)
Mortal pulp amputation
Never	27.5% (0.01)
Very rarely	34% (0.01)
Rarely	19.7% (0.01)
Often	14.7% (0.01)
Almost always- Always	4.2% (0.01)
Radiograph analysis before instrumentation
Never	0.64% (0)
Very rarely	2.3% (0)
Rarely	6.8% (0.01)
Often	34.9% (0.01)
Almost always	24.1% (0.01)
Always	31.2% (0.01)
Use of magnifying devices
Never	62.7% (0.01)
Very rarely	8.6% (0.01)
Rarely	8.9% (0.01)
Often	8.5% (0.01)
Almost always	3.3% (0.01)
Always	8.1% (0.01)
Use of CBCT
Never	58.9% (0.02)
Very rarely	13% (0.01)
Rarely	16.8% (0.01)
Often	11.3% (0.01)
Use of engine-driven instruments
Never	27.2% (0.01)
Very rarely	6.1% (0.01)
Rarely	7.7% (0.01)
Often	27% (0.01)
Almost always	17.4% (0.01)
Always	14.6% (0.01)
Manual instrumentation only
Never	2.3% (0)
Very rarely	11.6% (0.01)
Rarely	14.1% (0.01)
Often	29.1% (0.01)
Almost always	12.8% (0.01)
Always	30.1% (0.01)

Figure 1.

General characteristics of dental practitioners who participated in the survey: A-Years in practice; B- Continuing education in the last 5 years; C- Degree of clinical education

Figure 2.

Self-perceived root canals finding performance (3 respondents answered always to first mandibular molars, and 1 answered always to mandibular incisors).

Single-Visit Endodontic Therapy and Root Canal Detection

In Croatia, it is estimated that 27.9% of practitioners perform single-visit ET often to always (Table 1). Among specialists and residents in endodontics, this percentage is 62.5%. Male practitioners perform significantly more single-visit ETs than female practitioners (LO=0.6), for whom the singe-visit practice drops significantly with years of experience (LO=-0.04) (Figure 3). Continuous education has a small positive effect (LO=0.33), whereas endodontic specialists (EndoS) are performing it significantly more often (LO=1.89), but with a notable significant drop with years of experience (LO=-0.15). Panel D shows that polyclinics (Poly) and schools of dental medicine (SDM) are the only clinical settings that use single-visit ET more often than others. The usage increases with the number of endodontically treated teeth (LO=0.04). Starting from panel F, we see that single-visit ET is associated with increased usage of magnifying devices, rubber dam, radiographical checks before the procedure, CBCT, and a small but significant increase in reported analgesic prescription (panel J). Antibiotics are significantly less often prescribed by practitioners who perform single-visit ET often to almost always (LO=-0.18) (panel K), but there are more vertical fractures the more single-visit ET is practiced (panel L). As expected, manual instrumentation is less associated with single-visit ET, while engine-driven instrumentation is more used (panels M and N). We also tested if there were more apicectomies, if patients complained more about pain, and the influence of final irrigation, however, these three factors were not found significant.

Figure 3.

Effects of various factors on the single-visit ET practice. A - sex and years in practice; B-Continuing education in the last 5 years; C - Degree of clinical education (DDM – Doctor of Dental Medicine, EndoS – Specialist in Endodontics, EndoR – Resident in Endodontics, Other); D-Clinical setting (HC - Health Center, InConc - Dental Clinic with Concession Contract, Priv - Private Clinic, Priva SA - Private Clinic with a Health Fund Contract, Poly - Dental Polyclinic, SDM - School of Dental Medicine); E - No. of endodontically treated teeth; F - Magnifying devices; G - Rubber dam isolation; H - Radiograph before procedure; I - CBCT use; J - Analgesic prescription; K - Antibiotics prescription; L - Vertical fractures; M - Manual root canal instrumentation; N - Engine-driven root canal instrumentation.

Figure 4 shows that teeth with sinus tracts and periradicular lesions are less frequently treated in a single-visit, particularly in multiple-rooted teeth. Additionally, Figure 5 shows that pulpectomy is most frequently performed in one or two visits and that mortal extirpation is considerably used especially for molars (51.3%).

Figure 4.

Frequency of single-visit endodontics considering the number of roots and the status of periapical tissue.

Figure 5.

Pulp extirpation modality for incisors, premolars and molars.

Figures 6 to 8 show that practitioners’ self-perceived ability to find additional root canals decreases with years of clinical experience, while continuous education always has a positive effect. Furthermore, specialists (EndoS) are superior in finding canals than general dentists (DDM), as expected. Considering that EndoS mostly work in SDM and Poly clinical settings, it is not surprising that these two clinical settings stand out in finding canals (panels D). Panels E show that magnification has a considerable positive effect on finding canals, with additional light being significant for finding the second buccal mesial canal in maxillary molars and two canals in mandibular incisors (the light is especially helpful for practitioners who always use magnification). Analyzing the radiograph before the procedure has a strong positive effect, as well as CBCT, except for the second canal in the distal root of mandibular molars for which CBCT was not found significant. The last panel in Figures 6–8 shows that practitioners who perform single-visit ETs more often rate themselves as more successful in finding the additional canals.

Figure 6.

Self-perceived performance in finding the second bucco-mesial canal in maxillary molars and its association with: A - sex and years in practice; B - Continuing education in the last 5 years; C - Degree of clinical education (DDM – Doctor of Dental Medicine, EndoS – Specialist in Endodontics, EndoR – Resident in Endodontics, Other); D-Clinical setting (HC - Health Center, InConc - Dental Clinic with Concession Contract, Priv - Private Clinic, Priva SA - Private Clinic with a Health Fund Contract, Poly - Dental Polyclinic, SDM - School of Dental Medicine); E-Magnification and light; F - Radiograph before procedure; G - Engine-driven instrumentation; H - CBCT use; I - Single-visit ET.

Figure 7.

Self-perceived performance in finding a second canal in the distal root of mandibular molars and its association with: A-sex and years in practice Y; B- Continuing education in the last 5 years; C- Degree of clinical education (DDM – Doctor of Dental Medicine, EndoS – Specialist in Endodontics, EndoR – Resident in Endodontics, Other); D-Clinical setting (HC - Health Center, InConc - Dental Clinic with Concession Contract, Priv - Private Clinic, Priva SA - Private Clinic with a Health Fund Contract, Poly - Dental Polyclinic, SDM - School of Dental Medicine); E-Magnification (light was not significant); F- Radiograph before procedure; G-Engine-driven instrumentation; H-Single-visit ET.

Figure 8.

Self-perceived performance in finding two canals in mandibular incisors. A-Effects of sex and years in practice; B- Continuing education in the last 5 years; C- Degree of clinical education (DDM – Doctor of Dental Medicine, EndoS – Specialist in Endodontics, EndoR – Resident in Endodontics, Other); D-Clinical setting (HC - Health Center, InConc - Dental Clinic with Concession Contract, Priv - Private Clinic, Priva SA - Private Clinic with a Health Fund Contract, Poly - Dental Polyclinic, SDM - School of Dental Medicine); E-Magnification and light; F- Radiograph before procedure; G-Engine-driven instrumentation; H- CBCT use; I - Single visit ET.

Discussion

The number of responses collected (819) is satisfactory compared to a similar global survey within specialist endodontic practice that garnered 543 responses (50). The respondents were unevenly distributed by years of experience (Figure 1A), with a higher percentage of female respondents (F = 69.2%) compared to male respondents (M = 30.8%). The mean years of practice for both sexes were nearly equal (M = 21.7 years, F = 20.4 years). In contrast, a U.S. study reported that 75% of respondents were male, with 56% having more than 20 years of experience (51). Additionally, 80% of the Croatian respondents reported having completed continuous education in endodontics, as explored in greater detail by Sovic et al. in (52).

In Croatia, it is estimated that 27.9% of practitioners perform single-visit ET often to always. Other studies report varying averages, from 19% single-visit ETs in South Africa (53) to 63% in the United States (51). A recent study indicates that over 70% of endodontists and endodontic post-graduate students in the U.S., Europe, and the Middle East prefer single-visit treatment (50), which in Croatia corresponds to 62.5% of specialists and residents in endodontics performing single-visit ET often to always.

Single-visit ET in Croatia is associated with increased use of magnification, rubber dam isolation, radiographic imaging, and CBCT. Encouragingly, the more practitioners rely on single-visit ETs, the less frequently they prescribe antibiotics. This is in line with recent findings on postoperative pain, which suggest that “to relieve the patient from postoperative pain where complete debridement is possible, antibiotics can be excluded from the regimen and only analgesics should be prescribed” (33). We did not observe a significant increase in reported pain between visits or immediately after ET, which is consistent with a 2017 systematic review (1). However, this finding does not fully align with the most recent Cochrane review (42), which has found moderate certainty evidence for more patients reporting pain within one week after single-visit ET.

The absence of a significant increase in reported pain in our study may be related to the significantly higher rate of analgesic prescription among those who perform single-visit ET—an association not previously reported in studies from other countries (42). We also observed a significant increase in reported occurrence of vertical root fractures following treatment, which has not been documented in earlier studies. Although vertical root fractures can result from various factors such as improper design of the post-endodontic coronal restoration, inadequate preparation of the post space, excessive masticatory forces, and other mechanical stresses, the observed increase may also be related to the more frequent use of engine-driven instrumentation, which we found to be more commonly associated with single-visit ET. While engine-driven instruments are generally considered efficient, they have been perceived as having higher risk of root fractures. The stress levels leading to such fractures can vary depending on the instrument design, with stiffer instruments generating greater stress in the apical root dentin, particularly during shaping of curved canals (54). Further studies are needed to explore thoroughly specific types and usage protocols of engine-driven instruments.

Teeth with sinus tracts and periradicular lesions are less frequently treated in a single-visit, particularly in cases involving multiple-rooted teeth. Considering infected canals in teeth with periradicular lesions, with or without sinus tracts, and the highly complex anatomy of the endodontic space, particularly in multi-rooted teeth, it is understandable that clinicians may require additional time to establish the conditions necessary for completing treatment (1, 33). Our findings suggest that clinical education and working conditions play a significant role in these decisions.

European Society of Endodontology and American Association of Endodontists support immediate and biologically based treatments, such as pulpectomy or vital pulp therapy, over devitalization methods (55, 56). These approaches are associated with better patient outcomes and align with current evidence-based practices. Our respondents, however, reported using mortal amputation often in 14.7% and almost always to always in 4.2%, and mortal extirpation is considerably used especially for molars. We can only speculate that is mainly caused by the lack of time since heath centers in Croatia can be overcrowded. Supporting this claim is one respondent’s free text entry “There are so many patients in the health center that I'm just proud I still do endodontics.”

One of the primary reasons for endodontic treatment (ET) failure is the clinician’s inability to identify all root canals, particularly those that are very small or difficult to locate that may go undetected during the procedure (57). The proportion of practitioners who responded almost always to always being able to find two canals in specific teeth/roots should be analyzed in light of the average anatomical occurrences of these canals. For instance, Ingle’s textbook of endodontics (58) states that 40% of mandibular incisors have two canals, with only 2–3% having separate apical foramina. Gulabivala et al., (59), reported two coronal canals in the distal root of first permanent mandibular molars in 34.7% of cases, with 28% of them having two apical foramina. Similarly, Gilles (60) and Sert (61) found a second buccal-mesial canal in first permanent maxillary molars in approximately 90% of cases, with 38–39% having separate apical foramina.

The proportion of respondents who reported finding the second buccal-mesial canal often to always was 50%, compared to 90% likelihood of its presence. Similarly, 50% of respondents reported finding a second distal canal in the mandibular first molar often to almost always (Figure 2), which corresponds to 35% likelihood of its presence. For mandibular incisors, only 1% of respondents reported almost always finding two canals, and 19% reported finding them often, compared to a 40% likelihood of their presence. These findings suggest that, despite some subjectivity in responses, root canals are more frequently missed in the mandibular incisors and maxillary molars than in mandibular molars.

Figures 6–8 illustrate that efficiency in finding canals in molars and incisors declines with years of practice (significantly so for females). One might expect efficiency to improve with experience, but reduced eyesight, decreased investment in magnification tools, and a preference for more profitable and routine procedures may contribute to this decline.

Continuing education consistently shows a positive impact on the ability to locate root canals in all 3 Figures (0.53, 0.66, and 0.38 in LO, respectively). This aligns with the integration of courses covering root canal morphology, CBCT, magnification, and other relevant techniques into Croatian endodontic CE programs. Incorporating knowledge of canal anatomy into CE is essential, as the information learned during undergraduate education may become outdated over time (62).

Panel C in Figures 6-8 shows that endodontic specialists (EndoS) self-rate themselves as more adept at finding the mentioned canals, as expected, while general dental practitioners (DDMs) perceive themselves as less efficient. Practitioners at public health centers (HCs) and concessionary clinics (InConc) are less skilled at canal detection, while private clinics (PrivSA) perform significantly worse, except in mandibular molars. The School of Dental Medicine (SDM) excel in all areas except mandibular molars. These disparities are expected, as Poly and SDM settings are more populated with specialists and residents, unlike private clinics, which are primarily staffed by DDMs.

Magnifiers and added light result in a combined positive effect on finding canals in maxillary molars and incisors. Efficiency improves with magnification, and added light is especially beneficial for those who use magnifiers always. However, for distal roots in mandibular molars, light does not significantly affect efficiency, although magnifiers still improve outcomes. Pre-procedural radiographs also enhance canal detection (Panel F). Panel H shows that CBCT significantly improves detection of the second buccal-mesial canal in maxillary molars, consistent with findings that it is superior to digital radiography, magnification telescopes, and the naked eye (63). CBCT also positively affects canal detection in mandibular incisors, although no significant effect was observed for the second canal in distal mandibular molar roots.

While the benefits of magnifiers are clear, 63% of respondents reported never using them (Table 1). This is likely due to the high cost of magnifiers and their personalized nature, which prevents sharing between clinicians in the same clinic. Some practitioners may also avoid magnifiers due to personal beliefs that they might negatively impact eyesight.

Finally, the limitations of this study should be acknowledged. One major limitation is the difficulty in comparing this study with others globally due to the lack of standardized questionnaires. Developing a harmonized questionnaire for international studies would greatly enhance future comparisons and facilitate efforts to align endodontic practices across countries. Additionally, as this study is based on a questionnaire, it cannot directly correlate practices with clinical outcomes.

Conclusion

This study presents the first investigation into single-visit ET practices in Croatia, revealing that 27.9% of practitioners frequently perform single-visit ETs. Factors such as the use of advanced equipment (magnifiers, rubber dam, radiography, CBCT), clinical education, and workplace setting, significantly influence the adoption of single-visit ETs. While single-visit ET is associated with reduced antibiotic prescriptions, it also correlates with self-reported higher rates of vertical tooth fractures and increased analgesic prescription.

Practitioners who more frequently perform single-visit ETs also rate themselves higher in the ability to detect additional canals—a skill positively influenced by the use of radiography and magnification tools. These findings highlight the importance of continuous education that emphasizes vital pulp therapy and supports the integration of advanced technologies to enhance endodontic outcomes.

The results offer valuable insights into how clinical practices, available resources, and educational background interact to influence treatment approaches and perceived outcomes. Further research is needed to explore the potential implications of single-visit procedures, particularly the causes behind the increased prescription of analgesics and the possible rise in treatment-induced vertical fractures.