Circumstances behind the use of Cone Beam Computed Tomography for endodontic reasons in Sweden from the perspective of the referring dentist. Preliminary results.

Use of CBCT in endodontics

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Circumstances behind the use of Cone Beam Computed Tomography for endodontic reasons in Sweden from the perspective of the referring dentist.

Preliminary results.

Mota de Almeida FJ

, Flygare L

, Knutsson K

, Wolf E

1

Tandvårdens Kompetenscentrum, Norrbottens Region, Luleå;

Department of Radiation Sciences, Umeå University, Umeå;

Department of Oral-and-Maxillofacial Radiology, Malmö University;

Department of Endodontics, Faculty of Odontology, Malmö University, Malmö, Sweden

Abstract

Aim: To study the circumstances preceding the CBCT examination referral for endodontic reasons in Sweden.

Methodology: Fourteen dentists (8 female) 33-58 years of age (mean =44), practicing in Sweden were strategically selected. Ten of the dentists were specialists in endodontics. The absolute inclusion criterion was experience of referring patients for CBCT for endodontic reasons. The included dentists provided a variation concerning gender, age, work experience, education background, location of practice, service affiliation and accessibility to CBCT. Data was obtained through thematic, semi-structured interviews exposing the context of their last self-reported three referrals. Dentists were encouraged to describe their experiences of the circumstances in their own words, aided by the interviewer´s open-ended questions. The interviews were audio recorded and transcribed verbatim. Qualitative content analysis was used to analyze the text.

Results: The preliminary results may indicate that high clinical diagnostic standards, clinical common sense and a willingness of helping the patient with minimal harm may restrict the use of CBCT to address complex diagnostic judgements or therapeutic decisions, which comply with existing European guidelines on the use of CBCT in endodontics. Knowledge of guidelines was however limited among the interviewed dentists.

Conclusion: Common sense and high professional standards seem to lead dentists in Sweden to comply with current European guidelines for the use of CBCT in endodontics even when the dentists lack knowledge of the guidelines.

Introduction

Cone Beam Computed tomography (CBCT) is a more sensitive technique than conventional plane radiographs in endodontics at the expense of more radiation (European Commission 2012, Petersson et al. 2012). However, there is some concern about the use of CBCT in endodontics emanating from the main international professional

associations such as the European Society of Endodontology, the American Association of Endodontists and the American Academy of Oral and Maxillofacial Radiology. These organisations have issued their own guidelines, which are quite similar (American Association of Endodontists &

American Academy of Oral and Maxillofacial Radiology 2011, European Society of Endodontology 2014) and

generally recommend the use of CBCT only in complex cases.

The guidelines are of low quality (Horner et al. 2015). The European Commission (EC) has issued evidence-based guidelines after a thorough review of the literature (European Commision 2012). In our previous studies we have shown that when applying the EC guidelines, in a strict sense, the use of CBCT is limited to very few patients in endodontics Mota de Almeida et al. 2014a, Mota de Almeida et al. 2014b). This is in contrast to the great increase in the use of CBCT in the last

few years (Brown & Monsour 2014). This trend can be noticed in the volume of research produced, but also in the expanding market of CBCT machines (Nemtoi et al. 2013).

It should be a matter of concern if practitioners are not following guidelines, and using CBCT in a group of patients for which there is no evidence for justification. Data suggests that for at least those with relatively easily diagnosed apical periodontitis there would be no gain in using CBCT (Balasundaram et al. 2012). To the added economical and biological burden of a CBCT examination with no proven gain (in terms of patient benefit), one should add the concern that more sensitive technology is associated with overdiagnosis and overtreatment (Moynihan et al. 2012). Recent data suggests that this could also be the case for CBCT (Pope et al.

2014).

Aim

Our aim is to study the circumstances preceding the CBCT

examination referral for endodontic reasons in its context from

the perspective of the referring dentist.

Use of CBCT in endodontics

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Pre-understanding

We believed that endodontists referred patients without taking current guidelines into consideration. Other factors could be more influential. Our pre understanding included an implicit or explicit wish for economic compensation for an expensive investment (the CBCT machine); availability of the machine (as less available, less referrals); interaction with the patient;

and professional curiosity to be more important than current guidelines.

Material and methods Context

In Sweden, endodontists can practice in different

environments. They can work as the only specialist in the field, or with some other endodontists in larger inter- disciplinary clinics. This situation is the most common for public clinics, but it also occurs in the private sector.

Endodontists working alone, or in clinics only offering endodontic services are exclusively found in the private sector.

The availability of the CBCT machine is heterogeneous.

Endodontists usually need to write referrals when prescribing CBCT examinations. The implication of this is that patients generally have to wait for another day for the CBCT- examination, often in a different place as the machine can be located in a different clinic. There are however situations in which the examination can be performed straight away with no need for formal referral.

In Sweden, it is always a board-certified radiologist’s prerogative to decide whether CBCT should be performed, as well as which protocol to use, depending on the diagnostic task. Non-radiologists cannot independently operate CBCT equipment (Swedish Radiation Safety Authority 2008). In general radiologists control each examination – and the need of such examination – and then they write detailed reports.

Occasionally situations occur when a radiologist is responsible for the use of the machine, and issue local guidelines for its use, but do not control each specific examination.

Participants and recruitment

Swedish dentists exclusively practicing endodontics or with a special interest in endodontics were strategically selected from the lists of the Swedish Society of Endodontics, and from dentists advertising in the Journal of the Swedish Dental Association (Tandläkartidningen). The absolute inclusion criterion was that the dentist during the previous months had ordered a CBCT examination for some of their patients due to endodontic reasons. Furthermore, the selection aimed to get as much adequate diversity and breadth as possible regarding variables such as sex, years of experience, private versus public service, specialists versus general practitioners with special interest in endodontics, different undergraduate education, and geographical distribution in Sweden. Dentists (informants) were be contacted by telephone or post (e-post) in order to inquire if they were available to participate in the study. The aim of the study was briefly presented and they were asked to take part in an interview to be scheduled. They gave oral and written consent to participate in the study and

informed that they had the right to withdraw from the study at any time.

Their answers were anonymised when writing the manuscript so that they could not be traced back to the informant.

Data collection

A few days before the interview, the informant was contacted and asked to go through the records of the last three patients for whom the informant requested a CBCT examination due to endodontic reasons. The interviews took 30-60 minutes and were performed by one researcher (FA, endodontist). FA has knowledge of the guidelines, and prescribes CBCT

examinations himself. He had limited experience in qualitative research and interviewing.

Copies of the patients’ clinical records were available as a base for the interview. The informants were asked to remove the patient’s identification before the interview so the patient’s identity would be unknown to the researchers. The clinical records did not serve as a base of data to be analyzed, and were therefore not retained by the researchers.

A semi-structured interview was performed per informant at the informant´s own office. We had a special interest in what context the referral decision was made, including assessments done before referral and the communication with the

individual patient. The informants were encouraged to describe their experiences of the circumstances in their own words, aided by the interviewers´ open-ended questions. Follow-up

questions were asked in order to clarify the information given by the informant. The interviews were digitally tape-recorded and transcribed verbatim.

Two pilot interviews were previously performed by FA, in order for the researcher to get acquainted with the interview technique. A senior researcher (EW) with experience in qualitative research gave feed-back on those interviews. These interviews were not part of the study material.

Text preparation

Two researchers begun by reading the transcript of each interview several times, prior to the analysis, to obtain a sense of the whole (FA, EW). A researcher (FA) systematically identified and marked all meaning units, i.e. groups of words or sentences with the same content. The meaning units were condensed into more succinct formulations by excluding all unnecessary words.

Analysis

The condensed meaning units were abstracted into codes that reflected the central meaning of the unit (FA, EW

independently). These codes were clustered in accordance to

similarities and differences revealing varying patterns in the

informants´ experiences. To communicate the identified

patterns (descriptive level/manifest content), the codes were

then be organised into categories and subcategories (FA, EW,

KK). After reflection on and comparison of the categories, a

theme illustrating the interpretative level (latent content) (FA,

EW, LF, KK) was formulated. The four researchers reviewed

then the analysis results and compare them to get a sense of

Use of CBCT in endodontics

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the whole and of the parts. Supporting quotes to ensure viewpoints will be presented later in a non-partisan way. The quotations will be transcribed from spoken Swedish to written language and translated into English.

Results

When approximately 14 dentists were interviewed the collecting phase of the study was completed as saturation was felt to be achieved. Under the recruitment process two dentists refused to participate. Of the 14 dentists there were:

 8 women, 6 men;

 10 were Swedish, and 2 hade a non-Swedish background;

 10 were endodontists, 1 non-endodontist specialist and 3 GDP;

 7 worked in the public sector (universities, or county councils’ health services) and 7 in the private sector;

 5 were younger than 40, and 4 were older than 50;

 11 worked in the towns were dentistry schools are located (Stockholm, Gothenburg, Malmö and Umeå) and 3 in other locations.

The preliminary results may indicate that high clinical diagnostic standards, clinical common sense and a willingness of helping the patient with minimal harm may restrict the use of CBCT to address complex diagnostic judgements or therapeutic decisions, which comply with existing European guidelines on the use of CBCT in endodontics. Knowledge of guidelines was however limited among the interviewed dentists.

Discussion

Methodological considerations

Guidelines are a means of standardising and improving care quality but it is not unusual that clinicians’ practice diverges from them (Davies & Drage 2013, Tong et al. 2014).

Quantitative research methods can indicate some of the reasons for this divergence, such as lack of familiarity, or agreement with the guidelines, or lack of time (Cabana et al.

2001). However, qualitative research methods can explore in greater detail a wider array of factors that could explain non- adherence to guidelines. These factors might otherwise have been missed due to the researcher’s preconceptions (Espeland

& Baerheim 2003, Cope et al. 2014). The aim of qualitative research methods is to understand a specific phenomenon, and not generalize from sample to the population (Dahlström et al.

2017). Since little is known about the the endodontists’

experiences of the circumstances when referring patients for CBCT examination, an approach with qualitative

methodology allows a possibility to explore these issues.

There is some scepticism regarding qualitative methods, the main criticism concerns a lack of objectivity. But there is an array of measures that can be taken to improve validity (Malterud 2001). Qualitative methodology is not common in endodontic research. Only a few studies have been carried out (Gatten et al. 2011, Dahlström et al. 2017). No qualitative studies on the use of CBCT are known to us.

There was a risk of bias when collecting and analysing data as the researchers were well aware of the existence of the guidelines, and how CBCT (probably) should be used. As a consequence the researcher’s preconceived ideas could have guided the informants in an undesirable fashion through the interviews. One preconceived idea is that the availability and the simplicity of performing CBCT examinations influenced the decision making. Thus, there was an awareness on this subject among the researchers and consequently also an awareness of the importance of bracketing this pre-

understanding during the interviews. The interview technique facilitated bracketing of a pre-understanding since the informant is during the interview encouraged to describe experiences freely, and the researchers to just follow with open and deepening questions.

Another problem was that the informants might have adapted their stories to satisfy the researchers who might be regarded as authorities. This is of concern especially if they perceived the interview as a means of establishing whether or not the guidelines were being followed. We have stressed to them in the beginning of the interview that the aim was not to test knowledge but to understand the informant’s experiences and points of view (Cope et al. 2014). They were assured that their participation in the study would be anonymous.

Clinical relevance

In endodontics, the use of CBCT should be confined to very complex cases similar (American Association of Endodontists

& American Academy of Oral and Maxillofacial Radiology 2011, European Society of Endodontology 2014). But its use is increasing rapidly and it is important that clinicians adhere to the guidelines.

This study sheds some light on whether professionals are using CBCT properly or not in Sweden. We could better understand their reasoning when referring patients for CBCT.

This understanding could be important when planning implementation programmes based on evidence-based practice.

Ethical issues

The Regional Ethical Review Board, Lund University, Sweden has approved the study in its form (Dnr 2015/271).

Conclusion

The preliminary results seem to indicate that common sense, high diagnostic standards and willingness to help the patient with minimal harm lead dentists in Sweden to comply with current European guidelines for the use of CBCT in endodontics even when the dentists lack knowledge of the guidelines. These preliminary results must be taken very cautiously.

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