Discussion.
All persons participating in this study were attending a formal peer review session. These peer reviewactivities are part of an accreditation system in which 60% of the Flemish practitioners take part. The distribution of the age groups reflected the age distribution of the Flemish dental profession, with the greater number of graduates in the 1980s. Therefore, the group selected is likely to be representative of the general dental population in the Flemish part of Belgium. The group was represented by graduates from all Flemish universities.
The response rate was high, which would be expected when questionnaires are handed out personally and collected immediately after completion. This is in contrast with postal surveys where the response rates are generally lower. The majority of the respondents were general practitioners (85.7%), reflecting the fact that this is the area where the majority of dental treatment is provided in Belgium.
The use of rubber dam by Belgian dental practitioners was low. Only 7% of the practitioners used rubber dam in all cases, even though the use of rubber dam is taught in every dental school in Flanders. These results agree with other recent studies (Saunders et al. 1999, Whitworth et al.2000, Jenkins et al. 2001). There was no relation between the use of rubber dam and the time after graduation, indicating that its use in daily dental practice is abandoned quickly.
The majority of root canal treatments was carried out in two visits, even for teeth with single root canals. Similar results were found by Saunders et al. (1999) who studied general dental practitioners in Great Britain and Inamoto et al. (2002) with questionnaires sent to endodontists in the USA. The increased number of visits necessary for the treatment of multiple canals reflected the complexity of treating such cases. The number of appointments required for treatment is a matter of debate. One-visit root canal treatment is not encouraged for necrotic pulps (Sjogren et al. 1997,Trope et al. 1999), however, it could be argued that with more visits, the risk of contamination increases, especially in cases with more than two visits.
The majority of practitioners did not treat the fourth canal in maxillary first and second molars, even though it may be present in at least 60% of the maxillary first and second molars (Okumura 1927, Kulild & Peters 1990). Furthermore, approximately one-fifth of the respondents did not respond to the question on treating a C-shape in mandibular molars. We assume that the majority of the present practitioners were not aware of the true meaning of the C-shape in mandibular molars. A C-shaped root canal system is present in approximately 8% of the mandibular second molars (Cooke & Cox1979, Weine1998).The practitioners indicating treatment of C-shapes in over 50% probably had misinterpreted the question and saw the C-shape as a kidney shaped distal canal in lower molars. This became clear when the subject of C-shapes was discussed during the peer review sessions.
In this study sodium hypochlorite was most popular amongst most of the practitioners; in concentrations up to 5%, it was used in 82.4% of cases. Sodium hypochlorite combined with hydrogen peroxide and chlorhexidine has been described in the literature (Ingle & Bakland 1994) although the combination of sodium hypochlorite and hydrogen peroxide is not recommended (Harrison et al. 1978). Furthermore, the use of irrigants such as chloramine and saline are not recommended for endodontic use (Ingle & Bakland 1994, Heling & Chandler 1998) as they do not have the antimicrobial and tissue solving capacities of a sodium hypochlorite solution. A possible reason for not using sodium hypochlorite and using a weak solution may be related to the limited use of rubber dam (Saunders et al. 1999, Whitworth et al. 2000, Jenkins et al. 2001), but was not the case in the present study.
Correct estimation of the length of the root canal is essential and this can be established by tactile sense, using radiographs and/or by electronic devices. Radiographs with an instrument of known length in situ were used for length determination by virtually all respondents. Only a minority (3.5%) relied on tactile sense for estimation of the working length. This method is not recommended since it does not give reliable results due to anatomical obstructions and constrictions in the canals (Dummer et al. 1984). There was no subdivision in the question concerning the influence of tooth vitality (vital vs. necrotic pulps), but the results indicated that the majority of the respondents were aiming for a working length 1-2 mm short of the radiographic apex. Recent advances in endodontics have led to improved reliability of electronic length determination (De Moor et al.1999). However, these devices were not often used (20%).
K-files were the hand instruments of choice for root canal preparation for most of the practitioners. They were used solely or in combination with other root canal instruments. Reamers, although abandoned by many schools for routine preparation, were still used by more than half of the practitioners; H-files and Ni-Ti files were also widely used.
Ingle (1961) described a standardized method for root canal instrumentation and preparation, utilizing instruments of fixed size and taper, with matching points for obturation. This technique was taught widely and is known to be widely practised (Carrotte 2000b). Although he did not actually use the term ‘stepback’, Schilder (1974) described the sequential widening of the apical part of the canal and the technique was rapidly adopted and further developed. The data in the present study showed that a great number of the older practitioners still used the standardized method, though it was interesting to see that the stepback technique with or without orifice enlargement was well established. This finding is in contrast with the findings of Jenkins et al. (2001) who’s study showed that practitioners tended to use the technique they were taught. Apparently, the stepdown/stepback approach, which is taught at the Flemish universities during present-day undergraduate programmes and during postgraduate courses, was adopted by the majority of the practitioners participating in this study. Preparation techniques such as the crown-down technique, balanced force technique, crown-down pressureless technique or modified double-flared technique were not commonly used and were only known by a minority of the practitioners. This finding emphasizes the need for continuing postgraduate training in endodontics.
About one-third of the respondents were familiar with the more modern preparation techniques but it was clear that each of the presently available systems was different with various techniques and products. In this respect, an interesting finding was that about half of the respondents felt their root canal preparation could be improved. A small minority were dissatisfied with the result of their preparation technique.

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