Discussion.
The present study describes the considered need for endodontic referrals and the factors that influence the decision to refer an endodontic case in a selected group of Dutch general practitioners who had been willing to participate in this study. One could argue that the group of dentists that completed the questionnaires was not representative for the Dutch population of dentists. Indeed, these groups were chosen to represent those dentists who possessed most likely a certain level of knowledge in general, and were acquainted with the requirements an endodontic treatment should meet in particular. Dentists who participate in continuing education may make a sounder judgment in the decision when to refer a complex endodontic case than those who are beyond that level of knowledge.
Currently, there are 5858 general dentists maintaining their own practice in the Netherlands with a mean of 2550-2600 registered patients (data from the Dutch Dental Association (NMT)). This is in accordance with data of the practice size in the present study in which the majority of the respondents had 1500-3000 registered patients. In the current study, 283 questionnaires were returned which represents approximately 5% of Dutch general practitioners maintaining their own practice.
In the present study, the majority of respondents (83%) graduated more than 10 years ago. Caplan et al. (1999) showed that general practitioners working for more than 10 years in the same dental Health Maintenance Organization (HMO) and with more than 10 years experience in dentistry were more likely to refer than less experienced dentists. However, in the present study the time since qualification as expressed in three cohorts did not appear to be of influence on any of the variables. Inthe present study, the majority of respondents (87%) preferred referral to an endodontist above an oral surgeon. Actually, 26% of the respondents referred on a regular basis to an endodontist and an equal percentage always or often referred to an oral surgeon. The discrepancy between these figures might be explained by the fact that there are currently only 29 practising endodontists in the Netherlands who unfortunately are obliged to regulate the influx of patients with waiting lists. The current number of practising oral surgeons is, according to data of the NMT almost 200.The shortage of endodontists may also be an explanation for the fact that in the present study 66%of the respondents performed all root canal treatments themselves, although 93% did feel the necessity to refer. Geographic distribution of practices limited to endodontics may be another explanation for this phenomenon.
Comparison between members and nonmembers of the NVvE showed that members referred significantly fewer cases to the oral surgeon. One may speculate that NVvE members are more likely to be familiar with the requirements an endodontic treatment should meet, before surgery may be indicated.
Several studies have investigated the reasons for referring a patient for expert endodontic therapy (Harty 1992, Abbott 1994, Caplan et al. 1999). A survey in England showed that the most common reason for referral to practices limited to endodontics was for retreatment of previous root fillings (20% of patients), followed by inability to control pain and/or swelling (14%), and inability to diagnose the cause of the endodontic problem (13%) (Harty1992). A similar study in Western Australia (Abbott 1994) found the diagnosis and management of pain as the major reason for referral (24% of patients), followed by calcified/blocked canals (18%), endodontic retreatment (15%), trauma (13%), surgery (7%), and perforations (6%). Caplan et al. (1999) compared the perceived indications for referral of general practitioners with those of endodontists. Of all conditions, teeth in need of apicoectomy/retrofill were recommended for referral most often by general practitioners, with 84 and 95% ‘always or almost always’ referring patients with single-rooted and multirooted teeth, respectively.
General practitioners and endodontists do not always agree on indications for referral. Caplan et al. (1999) found that100% of the endodontists considered the presence of a radiographically calcified canal to be a condition in which ‘most of the time’ or ‘always or most always’ referral is indicated, whereas 61% of the general practitioners thought so. Another difference in indication for referral between general practitioners and endodontists was the condition in which the source of the pain could not be diagnosed (Caplan et al.1999). Again, 100% of the endodontists considered this to be a condition in which a general practitioner ‘always or most always’ should refer. Of the general practitioners, 37% held that view.
In the present study, the presence of an obstruction was a major reason to refer (90% of respondents). This is in accordance with the results of Caplan et al. (1999) who showed that more than three-quarters of the general practitioners tended to refer teeth with separated instruments or ledged canals. In the present study, an obstruction was defined as an obliteration, a calcified canal or the presence of a broken instrument. Saunders et al. (1999) showed that the presence of a perforation was considered to be an important factor by 87.1% of the respondents followed by the need for retreatment (76% of the respondents) and the history of repeated abscesses (66.5%), which is in accordance with the results of the present study.
In the study of Abbott (1994), the reasons for referral to a single Australian endodontic practice were analysed by reviewing 2000 patient records. In a similar study (Harty 1992), the reasons for referral to seven British practices limited to endodontics were analysed by recording information relating to every patient referred for treatment over a 3-week period. From the results of the study of Abbott (1994), it appeared that management of pain was the main reason for referral (24% of the patients). This was also concluded by Harty (1992), who found that in 14 and 13% of the referred cases, respectively, the dentist was unable to control pain/swelling or diagnose the endodontic problem.
Likewise, in the current study, the presence of persisting signs and/or symptoms (e.g. pain and/or swelling) was considered to be an important-to-very important factor to refer by 71% of the respondents. When rapid resolution of pain and swelling is the major objective of referral in these cases, these data may imply that endodontists have to treat a substantial number of patients on an emergency basis. Therefore, endodontic practice management should consider logistic support to provide this type of treatment.

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