G. M. G. Hommez, R. J. G. De Moor & M. Braem
Department of Operative Dentistry and Endodontology, Ghent University, Ghent University Hospital, Dental School, Gent, Belgium.
Department of Dental Materials, University of Antwerp, Campus RUCA, Antwerpen, Belgium.  

Introduction.
In Part1of this study (Hommez et al.2003), the opinions and views of a group of Flemish dentists regarding cleaning and shaping canals during root-canal treatment were reported.
The objective of root filling is to prevent passage of microorganisms and fluid between the canal system and periradicular tissues (ESE 1994). Unfortunately, longitudinal studies of endodontic treatment in general dental practice have shown large numbers of teeth with inadequate root fillings associated with periradicular disease. This inevitably results in a growing demand for further treatment. Re-treatment is clearly indicated when a periapical lesion, clinical signs or symptoms are present (Friedman & Stabholz 1986). Despite guidelines provided to simplify endodontic re-treatment decision making (ESE 1994, AAE 1998), large intra- and interindividual discrepancies remain in the estimation of endodontic re-treatment requirements (Aryanpour et al. 2000, McCaul et al. 2001). The complexity of the operative procedures and the variety of treatment alternatives introduce variation into the choice of therapy (Kvist et al. 1994). It has also been shown that decision making depends on the technical problems encountered and the clinical experience, confidence and training of general practitioners (Reit et al. 1985, Reit & Grondahl 1987). In this respect, it is also of interest to understand how practitioners deal with apical periodontitis and which cases are referred to endodontists for speciality treatment.
The first aim of this study was to gather information on root-canal filling, carried out by a group of dentists attending peer review sessions as a part of the program of the Belgianaccreditation system. Specific information was obtained on the basis of a questionnaire handed to dentists at these sessions organized by the ‘Interuniversitaire Samenwerking’ (Interuniversity Cooperation of the Flemish Universities) (Hommez et al. 2003). The aim of the questionnaire was not only to collect baseline data, but also to get an inventory of the present level of endodontic knowledge and on potential problems regarding endodontic treatment procedures.
The second aim of the study was to gain insight into endodontic treatment decision made in relation to periapical pathology and root-canal status and to make an inventory of cases considered for referral.

Materials and methods.
The information for this study was gathered through a questionnaire described previously (Hommez et al. 2003).
The present study deals with questions on canal medicaments and access cavities. In addition, information was gathered on filling techniques, sealers and use of caustic products. Decision making of dental practitioners regarding referrals and treatment options when confronted with periapical lesions of different size were also investigated.

Of the 312 questionnaires distributed, only two were not completed, giving a total of 99.4% completion; three questionnaires were discarded because the respondents did not perform endodontic treatment. In all 307 questionnaires (98.4%) were analyzed in this study.

Intracanal medication and temporary coronal-filling material.
Calcium hydroxide was used as an interappointment medicament by 69.7% of the practitioners. Approximately one-third (29.6%) of the practitioners did not use any dressing. Other nonspecified intracanal medicaments were used by 6.8% of the practitioners. The use of calciumhydroxide by year of graduation of the respondents is given in Table 1.Therewas no statistically significant difference between the age groups (P > 0.05), although there was a trend towards reduced use in the older age groups of the dentists.
Table 2 describes the use of caustic products in root canal treatment by the respondents. These chemicals were used by 66.8% of the respondents; Rockless1 (Specialites Septodont, Saint Maur, des Fosse. s, France) was used by most (34.2%) followed by Tempofore1 (Specialites Septodont) 26.4%. The preparation containing arsenic (Caustinerf Arsenic1) was used by 2.3% of the respondents. There was no statistically significant difference between the different graduation groups (time since graduation) as related to the use of caustic products (P > 0.05).
Table 3 summarizes the materials used for temporary filling of access cavities. Cavit1 (ESPE, Neus, Germany) was used by 48.2% of the respondents, followed by glass-ionomer (31.3%), zinc oxide-eugenol (27.0%) and IRM1 (Dentsply De Trey, Konstanz, Germany) 15.3%. Resin composite (1.6%) and amalgam (1.6%) were seldom used and other unspecified materials were used by 5.2% of the respondents. The time since graduation had no statistically significant influence (P > 0.05) on the choice of temporary filling material.

Table 1. Use of calciumhydroxide related to the time since graduation.



Table 2. Caustic products used during root-canal therapy according to the period since qualification.



Table 3. Materials used for temporary filling of the access cavity according to the period since qualification.

Filling of the root canal.
The different techniques used by the respondents to fill root canals are listed in Table 4. Cold lateral condensation of gutta-percha was the technique used by most respondents (65.8%). The other techniques were used infrequently (in descending order): single-cone gutta-percha (16.0%),Thermafil1 (Maillefer, Ballaigues, Switzerland) (12.4%) vertical condensation (11.7%), warm lateral condensation (10.1%), thermomechanical compaction of gutta-percha (5.5%), paste technique (4.9%), silver points (3.9%) and Soft-Core1 (0.7%) (Soft- Core DPAPS, Copenhagen, Denmark). Cold lateral condensation was used by 82.9% of the respondents who had graduated inthelatest5 years (Table 5). This percentage dropped with the time since graduation to 48.0% of the respondents who had graduated more than 25 years ago. Conversely, the use of single-cone guttapercha techniques and pastes increased with age.
Table 6 lists the root-canal sealers used by the respondents. AH-plus1 (Dentsply De Trey) was used by 37.8% of the respondents followed by34.5%forAH-261(Dentsply DeTrey).The other sealers listed in descending order of preference were: Topseal1 (Maillefer) 16.3%; Sealapex1 (Kerr Corporation, Orange, CA, USA) 15.0%; Endomethasone1 (Specialites Septodont, Saint Maur, des Fosse. s, France) 11.7%; Tubliseal1 (Kerr Corporation) 11.7%; Zinc oxide-eugenol,7.2%; N2 1 (Hager & Werken GmbH, Duisburg, Germany) 2.0%; Ketac-Endo1 (ESPE) 1.0% and Grossman’s sealer1 (Cartensen, Medex Omicron, Buenos Aires, Argentina) 0.7%. Table 7 describes the root-canal sealers used in relation to the obturation technique.
Nearly half the respondents (48.9%) were satisfied with their filling technique, 43.0% felt that they could perform better 0.7% were not satisfied and 7.5% did not answer the question.
Endodontic (re)treatment decision making Four out of five respondents performed root-canal retreatments. The following solvents were used in descending order: chloroform (36.5%); Endosolv E1 (Specialites Septodont) (8.8%); Endosolv R1 (Specialites Septodont) (5.2%); turpentine (4.2%); other not specified solvents were used by 3.9%. One-quarter of the respondents (25.4%) never used solvents during endodontic re-treatment.
The respondents were asked to rate their attitude towards referring endodontic cases on a scale from 1 to 10.Ascore of1meant the practitioner did not refer, whilst 10 meant the practitioner was enthusiastic about endodontic referral. The majority rated between 1 and 5 (64.5%); only 35.5% rated endodontic referral more than 5.
Table 8 gives an overview on treatment decision making in specific situations. When no root filling was present and a periapical lesion less than 1 cm wide was seen on a radiograph, the majority of the respondents (90.9%) performed conventional root-canal treatment in one or more visits. If the periapical lesion, in absence of a root filling, was wider than 1 cm, the number of respondents that chose conventional root-canal treatment dropped to 57.3%. In addition, more respondents chose conventional root-canal treatment followed by an apicectomy (26.4%), referral to an endodontist (18.2%) and extraction (8.5%) as a treatment option. When a root filling was present and a small lesion (less than 1 cm wide) was visible on a radiograph, 62.5% of the respondents chose conventional root-canal re-treatment; 12.7% elected for apicectomy, 15.0%of cases would be referred. When a periapical lesion of more than 1 cm wide in combination with a root filling was present, the decisions of the respondents were ambiguous. Only 31.2% would perform root-canal re-treatment, 27.0% would carry out a root-canal re-treatment followed by an apicectomy. Referral in these cases was frequently chosen (24.8%) as well as apicectomy alone (17.3%) and extraction (15.0%). In these four situations, the older practitioners opted more often for referral.
Table 9 gives an overview of cases that respondents would consider for referral to an endodontist. Retrieval of silver points was the most popular reason for referral (56.7%), followed by surgical closure of perforations (47.6%) and surgical interventions (45.9%). Other referral cases in descending order were: post removal (39.4%), dens invaginatus (38.4%), trauma (37.1%),mutilated canal (36.2%), canal splitting in the apical third (34.9%), internal root resorption (33.9%), S-shaped (bayonet shaped) root canal (33.6%), calcified canal (33.2%), curved root canal (32.9%), missed canal (32.2%), external resorption (31.6%), root perforation (28.3%), large periapical lesion (25.1%), endodontic retreatment (15.6%), apexification procedure (15.3%), endodontic treatment of deciduous teeth (7.5%) and treatment of molar teeth (5.5%).

Table 4. Techniques used to obturate the root canal according to the period since qualification.



Table 5. Root-canal obturation technique related to the time since graduation.



Table 6. Root-canal sealers used by the respondents.



Table 8. Endodontic (re)treatment decision making in relation to periapical pathology and root canal status.



Table 9. Endodontic referral cases according to the number of respondents (n = 307).

Discussion.
Calcium hydroxide is recommended as the standard intracanal dressing in root-canal treatment (Bystrom et al. 1985, Sjogren et al. 1991). In the present study, calcium hydroxide was used by 69.7% of the respondents, which is considerably more than the 21.1% in the study of Saunders et al. (1999), the 7% in the study of Jenkins et al. (2001) in the UK or the 9% in the USA (Whitten et al.1996). Ina Dutch study (Siers et al. 2001), the percentage of respondents using calcium hydroxide was 86.2%. These differences between countries are likely to be attributed to the different policies in dental training between universities (Qualtrough et al.1999). Although there was no statistically significant difference between the different age groups in this study, a similar trend, namely a decreased use of calcium hydroxide as a function of the period since graduation of the participants (Table 1) was observed as in some of the previous studies (Saunders et al.1999, Jenkins et al.2001).About one-third of the practitioners did not use an interappointment medicament. Studies have shown that it is almost impossible to create a sterile root canal through cleaning and shaping of the root-canal system and that regrowth of bacteria occurs in an empty root canal (Bystrom & Sundqvist1981, Siqueira et al.2002).Therefore, an intracanal dressing is advocated between appointments when a tooth is treated in more than one session.
Caustic and organic root-canal disinfectants were used by 66.8% (Table 2), despite the well-established use of calcium hydroxide. These products contain organic components such as paraformaldehyde, chlorophenol, parachloromonophenol, creosote, arsenicum anhydride, iodoform. It has been argued that most of these products should be prohibited as they are highly toxic, allergenic, mutagenic and carcinogenic and are harmful to patients (Lewis1998). It has been shown that some of these products caused periodontal destruction and delayed healing of periapical tissues (Kopczyk et al. 1986, Yamasaki et al. 1994, Di Felice & Lombardi 1998), as they can escape from the root canal. In this respect, studies have documented their rapid and strong systemic distribution when used during endodontic treatment (Block et al.1983, Fager & Messer 1986).
The sealing of access cavities between appointments is a determining factor in the inhibition of bacterial leakage and hence the prognosis of root-canal treatment (Saunders & Saunders1994). Cavit1 is the product most favoured by Belgian practitioners (48.2%), with glassionomers being used by 31.3% of the respondents. Studies have shown that Cavit1 adequately sealed access cavities of endodontically treated teeth (Beach et al. 1996), although a bacterial study (Barthel et al. 1999) reported that glass-ionomer was superior to Cavit1.
Cold lateral gutta-percha condensation was the filling technique most frequently used (Table 4). Although it is common knowledge that single-cone gutta-percha fillings are not recommended (Beatty1987), it was still used by16.0% of the respondents. The results in Table 5 show that different types of warm gutta-percha filling techniques were used by all ages. This clearly shows the effort made by a number of practitioners to use other filling techniques than those taught during dental graduate training.
This study also provided information on the endodontic decision making of the participants. On one hand, re-treatment of failed root fillings was the standard choice by the majority of the respondents (Table 8). On the other hand, there was a clear trend towards more apicectomies and extractions with the increase of the size of the periapical lesion. The number of apicectomies and extractions even increased when the lesion was associated with root-filled teeth. Studies have shown that the size of the periapical lesion is not a determining factor in healing (Sjogren et al.1990). The presence of a root filling is also no reason for more radical treatments. Re-treatment should always be the first option, although a number of complicating factors require surgery (Walton & Torabinejad1996).

References.

American Association of Endodontists (1998) Appropriateness   of Care and Quality Assurance Guidelines, 3rd edn. Chicago, IL, USA: American   Association of Endodontists.
Aryanpour S, Van Nieuwenhuysen J-P, D'Hoore W (2000) Endodontic re-treatment   decisions: no consensus. International Endodontic Journal 33, 208-18.
Barthel CR, Strobach A, Briedigkeit H, Gobel UB, Roulet JF (1999) Leakage   of roots coronally sealed with different temporary fillings. Journal of   Endodontics 25, 731-4.
Beach CW, Calhoun JC, Bramwell JD, Hutter JW, Miller GA(1996) Clinical evaluation   of bacterial leakage of endodontic temporary filling materials. Journal   of Endodontics 22, 459-62.
Beatty RG (1987) The effect of standard or serial preparation on single-cone   obturations. International Endodontic Journal 20, 276-81.
Block RM, Lewis RD, Hirsch J, Coffey J, Langeland K (1983) Systemic distribution   of [14C]-labeled paraformaldehyde incorporated within formocresol following   pulpotomies in dogs. Journal of Endodontics 9, 176-89.
Bystrom A, Sundqvist G (1981) Bacteriologic evaluation of the efficacy of   mechanical root canal instrumentation in endodontic therapy. Scandinavian   Journal of Dental Research 89, 321-8.
Bystrom A, Claesson R, Sundqvist G (1985) The antibacterial effect of camphorated   paramonochlorphenol, camphorated phenol and calcium hydroxide in the treatment   of infected root canals. Endodontics and Dental Traumatology 1, 170-5.
Di Felice R, Lombardi T (1998) Gingival and mandibular bone necrosis caused   by a paraformaldehyde-containing paste. Endodontics and DentalTraumatology14,   196-8.
European Society of Endodontology (1994) Consensus report of the European   Society of Endodontology on quality guidelines for endodontic treatment.   International Endodontic Journal 27, 115-24.
Fager FK, Messer HH (1986) Systemic distribution of camphorated monochorophenol   from cotton pellets sealed in pulp chambers. Journal of Endodontics 12,   225-30.
Friedman S, Stabholz A (1986) Endodontic re-treatment-case selection and   technique. Part 1. Criteria for case selection. Journal of Endodontics12,   28-33.
Hommez GMG, Braem M, DeMoor RJG (2003) Endodontic treatment performed by   Flemish dentists. Part 1. Cleaning and shaping. International Endodontic   Journal 36, 766-73.
Jenkins SM, Hayes SJ, Dummer PMH (2001) A study of endodontic treatment carried   out in dental practice within the UK. International Endodontic Journal 34,   16-22.
Kopczyk RA, Cunningham CJ, Abrams H (1986) Periodontal implications of formocresol   medication. Journal of Endodontics 12, 567-9.
Kvist T, Reit C, Esposito Met al. (1994) Prescribing endodontic retreatment:   towards a theory of dentist behaviour. International Endodontic Journal   27, 285-90.
Lewis B (1998) Formaldehyde in dentistry: a review for the millennium.   Journal of Clinical Pediatric Dentistry 22, 167-77.
McCaul LK, McHugh S, Saunders WP (2001) The influence of speciality training   and experience on decision making in endodontic diagnosis and treatment planning.   International Endodontic Journal 34, 594-606.
Qualtrough AJE, Whitworth JM, Dummer PMH (1999) Preclinical endodontology:   an international comparison. International Endodontic Journal 32, 406-14.
Reit C, Grondahl HG (1987) Endodontic decision-making under uncertainty:   a decision-analytic approach to management of periapical lesions in endodontically   treated teeth. Endodontics and Dental Traumatology 3,15-20.
Reit C, Grondahl HG, Engstrom B (1985) Endodontic re-treatment decisions:   a study of the clinical decision-making process. Endodontics and Dental   Traumatology 1, 102-7.
Saunders WP, Chestnutt IG, Saunders EM(1999) Factors influencing the diagnosis   and management of teeth with pulpal and periradicular disease by general dental   practitioners. Part 2. British Dental Journal 187, 548-54.
Saunders WP, Saunders EM (1994) Coronal leakage as a cause of failure in   root-canal therapy. Endodontics and Dental Traumatology10, 105- 8.
Siers ML,Willemsen WL, Bronkhorst EM (2001) Middelen voor toepassing in het   wortelkanaal gebruikt door algemeen practice. Nederlands Tijdschrift Voor   Tandheelkunde 108, 398-400.
Siqueira JF, Jr, Rjcas IN, Santos SR, Lima KC, Magalhaes FA, de Useda M( 2002)   Efficacy of instrumentation techniques and irrigation regimens in reducing   the bacterial population within root canals. Journal of Endodontics 28,   181-4.
Sjogren U, Figdor D, SpTngberg L, Sundqvist G (1991) The antimicrobial effect   of calcium hydroxide as a short-term intracanal dressing. International   Endodontic Journal 24, 119-25.
Sjogren U, Hagglund B, Sundqvist G, Wing K (1990) Factors affecting the long-term   result of endodontic treatment. Journal of Endodontics 16, 498-504.
Walton RE, Torabinejad M (1996) Principles and Practice of Endodontics, 2nd   edn (Chapter 20). Philadelphia, PA, USA: W.B. Saunders Co.
Whitten BH, Gardiner DL, Jeansonne BG, Lemon RR (1996) Current trends in   endodontic treatment: report of a national survey. Journal of the American   Dental Association 127, 1333-41.
Yamasaki M, Nakamura H, Kameyama Y (1994) Irritating effect of formocresol   after pulpectomy in vivo. International Endodontic Journal 27, 245-51.