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Radiographic assessment of the quality of root canal fillings performed by senior dental students.

INTRODUCTION

One of the most important aims of a root canal filling is to prevent the reinfection of root canals that have been biomechanically instrumented, irrigated, disinfected, and obturated (1). According to the American Association of Endodontists (AAE), there are clinical and radiographic criteria for judging the technical success of a root canal filling (2). Clinically, for a case to be considered successful, routine tests such as palpation, percussion, periodontal probing, and visual inspection of the final coronal restoration should reveal normal findings during periodical follow-up visits. The following three criteria should be radiographically assessed: length, shape, and density (2).

According to the guidelines of the European Society of Endodontology (ESE), the radiographic criteria of an adequate root canal treatment includes a prepared root canal with a consistent taper from the orifice to the apex and an obturated root canal that is completely without voids between the canal filling and canal walls. It is important that the root canal filling should be placed as close to the apical constriction as possible, i.e., within 0.5-2 mm of the radiographical apex (3).

Teaching endodontics to undergraduate students is one of the most complicated tasks for dental academics and one of the greatest challenges across all dental branches (4). The main educational purpose of endodontics is to successfully consolidate skill and knowledge as a base for graduates to become proficient and competent in clinical work (3).

Generally, dental curricula in most dental schools worldwide comprise pre-clinical training in endodontics during inaugural classes, where students are trained to perform root canal treatment on extracted teeth; however, during advanced classes, students clinically perform nonsurgical root canal treatment of anterior and posterior teeth (5, 6, 7, 8).

The quality of root canal fillings performed by dental students is well documented in the literature (9, 10, 11, 12, 13, 14) with different results in term of the acceptability of root canal fillings ranging from 13% reported by Hayes et al 2001 (9) to 84.1% reported by Kelbauskas et al 2009 (15).

The objective of the present study is to assess the radiographic technical quality of root canal fillings performed by senior dental students at Alfarabi college for dentistry and nursing, KSA and compare the results of our study with those of other investigations conducted in this area of endodontics.

MATERIALS AND METHODS

This study was based on pooled data from the radiographic unit of Alfarabi college for dentistry. In total, 246 records of patients who had received root canal treatment by undergraduate students during 2016-2017 were selected to evaluate the radiographic quality of the root canal fillings. The inclusion criterion for this selection was all root canal treatments performed by 6th year undergraduate dental students on adult patients with completely formed teeth.

All selected endodontics records had at least three high-quality radiographs, including the preoperative working length determination and postoperative radiographs. All selected radiographs were digital and displayed the entire length of the root and the periapical area, and the mesial and distal angulated radiographs were included for multi-rooted teeth.

The radiographic technical quality of the root canal fillings was independently evaluated by two expert endodontists, and the result was recorded when there was an agreement between the two examiners. The intra-examiner reliability was calculated by rechecking a random sample of 5% (19) of the total root canals previously examined. A 95% agreement was found, indicating that the scoring methods were reliable. The inter-examiner reproducibility was determined by calculating the kappa values, which were >0.9, indicating a high degree of inter-examiner agreement.

To assess the technical quality of root canal fillings, three criteria were evaluated as follows:

* Length of root canal filling, which includes four parameters: root filling ending [less than or equal to]2 mm from the radiographic apex, root filling ending >2 mm from the radiographic apex, root filling beyond the radiographic apex (over filling), or root filling at the radiographic apex (flush).

* Density of root canal filling, which includes two parameters: the presence or absence of voids in the root filling or between the root filling and root canal walls.

* Taper of the root canal filling, which includes two parameters: consistent taper from the orifice to the apex or no consistent taper from the orifice to the apex.

Finally, the technical quality of the root canal fillings considered acceptable if the root filling ended [less than or equal to]2 mm from the radiographic apex with no voids visible within the material or between the material and the root canal walls and consistent taper from the orifice to the apex (Figure 1).

In contrast, the technical quality of the root canal fillings was considered unacceptable when one or more of the aforementioned parameters were absent (Figure 2).

All root canal treatments evaluated in this study were conducted by students in an aseptic field with rubber dam isolation using the step-back technique for the root canal preparation and the cold lateral condensation technique for the root canal filling.

Each root canal assessed in this study was instrumented with the step-back technique using stainless steel manual K-files of 0.02 taper (Mani Inc., Tochigi-Ken, Japan). All canals were instrumented to the working length till a size #35 apically and a size #70 coronally. The working length was determined by an apex locator (Root ZX; Morita, Tokyo, Japan) and confirmed by a periapical radiograph. Gates-Glidden burs numbers 2, 3, and 4 in most cases were used in the coronal third of the root canals in order to facilitate straight line access. The root canals were irrigated with 2.5% NaOCl and 17% EDTA (MDCleanser, META Biomed, Korea). All root canals were obturated during a next appointment with gutta-percha points (ALPHA-DENT, North Hamlin Avenue, Lincolnwood, USA) and an AH plus sealer ((Dentsply De Trey GmbH, Konstanz, Germany) using the cold lateral condensation technique. All gutta-percha cones and spreaders were of 2% taper. At least five radiographs were taken at different steps during the treatment: preoperative radiograph, initial file radiograph, cleaning and shaping radiograph, master cone radiograph, and obturation radiograph.

All assessed radiographs in this study were obtained using a dental X-ray unit (Kodak, Carestream Health, USA) and a digital sensor (Fona, Sevcenkova 34, Slovak Republic).

The data were analyzed with descriptive statistical methods including the Kruskal--Wallis, Mann--Whitney, and chi-square tests (P=0.05) using the SPSS software (SPSS version 13.0, SPSS, Chicago, IL, USA). The level of significance was set at 0.05.

RESULTS

In this study, 390 root canal fillings from 246 patients were examined to assess the technical quality of the root canal fillings. The detailed results of the three criteria used to evaluate the technical quality of the root canal fillings according to the tooth type are presented in Tables 1, 2, and 3.

Of the 390 root canal treatments performed by 6th year undergraduate dental students, acceptable root canal fillings were detected in 127 (32.6%) patients, whereas unacceptable root canal fillings were detected in 263 (67.4%) patients. According to the tooth type, the number of accepted cases was distributed as follows: 15 (32.6%) in upper molars, 39 (30.2%) in lower molars, 28 (40%) in upper incisors, 13 (35.1%) in lower incisors, 18 (26.8%) in upper premolars, and 14 (34.1%) in lower premolars (Table 4). The frequency of an acceptable root canal filling in the same tooth type was significantly lesser in upper premolars, lower premolars, upper molars, and lower molars (P<0.05).

The percentage of root canal fillings with acceptable length was 59.48%, with acceptable density was 50.76%, and with consistent taper was 57.43%. The length of a root canal filling was the best criteria performed by the undergraduate students, followed by taper and density (Table 5).

The frequency of an adequate length of a root canal filling (root filling ending [less than or equal to]2 mm from the radiographic apex) was higher for lower molars (60/25.9%) than for lower incisors and lower premolars (24/10.3%). There was a significant difference in the length of the root canal filling among the types of teeth (P=0.031).

In terms of density of the root canal filling, the presence of voids was most frequent in lower molars (60/31.2%) than in lower incisors (16/8.3%). The best result for density (no voids) was obtained for upper molars (12/6.1%). There was a significant difference in the density of the root canal filling among the types of teeth (P=0.02).

The frequency of no consistent taper from the orifice to the apex was the highest for lower molars (60/36.1%) and lowest for lower incisors (12/7.2%). There was no significant difference in the taper of the root canal filling among the types of teeth (P=0.094). The detailed results of the Kruskal--Wallis test for evaluating the association between the quality of the root canal filling criteria and tooth type are presented in Table 6.

The comparison of length and density of the root canal filling among all tooth types revealed that the density of the root canal filling was significantly better for upper molars than for other teeth (P<0.05); the length of the root canal filling was significantly worse for lower molars than for upper premolars and upper incisors (P<0.05). In addition, there was no significant difference in the density and length among other tooth types (P>0.05). The detailed results of the Mann--Whitney test for comparing the length and density of root canal fillings among all tooth types are presented in Table 7.

DISCUSSION

It has been reported that the technical quality of root canal treatment may affect the outcome of root canal treatment and the health of periradicular tissues (16, 17, 18). A successful endodontic therapy is usually associated with root canal fillings that end within 2 mm of the radiographic apex and are of adequate homogeneity with no voids (19, 20).

Several studies have shown that the standard of root canal treatment performed by undergraduate students and general dental practitioners is poor (9, 6, 21, 22). Therefore, the present study was conducted to evaluate the technical quality of root canal fillings performed by senior dental students in XXXXX colleges (KSA) and compare our results with those of previous studies.

In this study, the criteria used to evaluate the quality of root canal fillings and categorize root fillings as acceptable or unacceptable were length, density, and taper. These criteria have been used in many previous studies (6, 8, 10, 13, 14).

In our study, out of 390 root canal treatments performed by 6th year undergraduate dental students, acceptable root canal fillings were detected in 32.6% of patients. This result is similar to that of Moussa-Badran et al 2008, Er et al 2006, Chueh et al 2003 (12, 23, 24). The rate of acceptable cases in these studies was 33%, 30.3%, and 30%, respectively. However, the result of the present study was not in agreement with that of studies by Khabbaz et al 2010, Unal et al 2011, Barrieshi-Nusair et al 2004, Lynch and Burke 2006, Kelbauskas et al 2009, and Roman-Richon et al 2014 (5, 7, 10, 11, 15, 25). The rate of successful cases in these studies was higher than that obtained in our study: 54.8%, 73.7%, 47.4%, 63%, 84.1%, and 44%, respectively. However, the rate of acceptable cases was lower in studies by Balto et al 2010, Hayes et al 2001, Elsayed et al 2011: 23%, 13%, and 24.2%, respectively.

In our study, the length of root canal fillings was the best criteria performed by the undergraduate students; this result is similar to that of Balto et al 2010, Roman-Richon et al 2014, Moradi and Gharechahi 2013 (6, 25, 26) but was not in agreement with the result of the study by Elemam et al 2015 (8).

The percentage of root canal fillings with consistent taper was 57.43%, which was lower than that reported by Balto et al 2010, Elemam et al 2015, Roman-Richon et al 2014 (6, 8, 25). The high percentage of root canal fillings with consistent taper (71%) reported by Roman-Richon et al 2014 (25) may be due to the instrumentation of root canals using rotary files.

The percentage of adequate density of root canal fillings in the current study was 50.76%, which was lower than that reported by Elemam et al 2015, Kelbauskas et al 2009, and Roman-Richon et al 2014 (8, 15, 25). The rates of adequate density in these studies were 75.8%, 79.5%, and 69%, respectively. However, our result was higher than that reported by Balto et al 2010 (6) and Moussa-Badran et al 2008 (12). In these studies, 34.9% and 42.7% of cases, respectively, had a dense root canal filling without voids.

It is well known that the anatomy and the root canal therapy of anterior teeth are less complicated than those of posterior teeth, particularly the maxilla. The frequency of an acceptable root canal filling in this study was the highest for the upper anterior teeth (40%), followed by the lower anterior teeth (35.1%); this result was consistent with that of previous studies (5, 6, 8, 12).

A wide range of results has been obtained from different studies evaluating the quality of root canal fillings performed by dental students or general practitioners. In fact, several factors may impact these outcomes. The methodology, criteria, and parameters varied among different studies. Some studies radiographically assessed only the length and density of root canal fillings but omitted the taper variable (5,7,12). However, other studies have incorporated the taper variable (6,8,13,14,25). Procedural errors have also been radiographically assessed to evaluate the quality of root canal fillings (5,6,11). There is an association between the rate of acceptable root canal fillings and the practitioners performing the root canal treatment. The percentage of acceptable root canal fillings was 91% when the root canal treatment was performed by an endodontist (27). Lower rates were obtained when the root canal treatment was performed by general practitioners (22,28) and senior (5,6) or inaugural dental students (8,14). Some studies have concluded that the percentage of technical success was highly improved with the rotary in-strumentation of root canals (15, 25).

This study and several previous studies has shown poor performance of undergraduate students in the root filling area; this may be due to the complications of root canal treatment and lack of basic experience, in addition to poor skill of many dental students in this branch of dentistry.

It is conceded that the skill and competence of practitioners or endodontists to achieve accurate root canal treatment may be linked to the amount of pre-clinical and clinical teaching in endodontics at dental schools. Some commissions such as AAE and ESE have formulated treatment guidelines in the area of endodontics that are intended to represent current good practices through which graduates would shortly be expected to serve the community.

CONCLUSION

The quality of root canal fillings performed by senior undergraduate dental students at Alfarabi colleges for dentistry and nursing, Riyadh (KSA) was acceptable in 32.6% of patients. This outcome enhanced the poor performance of undergraduate dental students in the area of endodontics.

Disclosures

Conflict of interest: No conflict of interest was declared by the authors.

Ethics Committee Approval: This study has been conducted in full accordance with the World Medical Association Declaration of Helsinki, with an approval from the Ethics Committee in Alfarabi colleges for dentistry and nursing, Riyadh, Saudi Arabia. (Ref. 00219/2017).

Peer-review: Externally peer-reviewed.

Financial Disclosure: The authors declared that this study has received no financial support.

Authorship contributions: Concept--M.D.D.; Design--A.A.H.; Supervision--A.A.H., M.Z.N.; Data collection &/or processing--E.S., B.S.J., H.A.A., S.A.M.; Analysis and/or interpretation--A.A.H., M.D.D., M.Z.N.; Literature search--A.A.H.; Writing--A.A.H.

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(24.) Chueh LH, Chen SC, Lee CM, Hsu YY, Pai SF, Kuo ML, et al. Technical quality of root canal treatment in Taiwan. Int Endod J 2003; 36(6):416-22.

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Adnan Asaad HABIB, Mazen Deib DOUMANI, Mohammad Zakaria NASSANI, Enass SHAMSY, Basma Safwan JTO, Hiba Ahmad ARWADI, Sagal Ahmad MOHAMED

Please cite this article as: Habib AA, Doumani MD, Nassani MZ, Shamsy E, Jto BS, Arwadi HA, et al. Radiographic assessment of the quality of root canal fillings performed by senior dental students. Eur Endod J 2018; 3: 101-6

From the Department of Restorative Dental Sciences (A.A.H. [??] adnanhabib71@hotmail.com, M.D.D., B.S.J., H.A.A., S.A.M.) AlFarabi College for Dentistry and Nursing, Riyadh, Saudi Arabia; Department of Prosthetic Dental Sciences, (M.Z.N.), AlFarabi College for Dentistry and Nursing, Riyadh, Saudi Arabia; Department of Dental Health Care, (E.S.), Inaya Medical College, Riyadh, Saudi Arabia

Received 23 February 2018, last revision received 12 March 2018, accepted 09 March 2018

Published online: 19 July 2018

DOI 10.14744/eej.2018.69775

HIGHLIGHTS

* Teaching endodontics to undergraduate students is one of the most complicated tasks for dental academics and one of the greatest challenges across all dental branches.

* The radiographic criteria of an acceptable root canal filling includes adequate length with no voids visible within the material or between the material and the root canal walls and consistent taper from the orifice to the apex.

* The amount of pre-clinical and clinical teaching in endodontics at the dental schools influences the skill and competence of practitioners or endodontists to achieve accurate root canal treatment.
TABLE 1. The frequency and percentage of the length of root canal
fillings according to the tooth type

                        Tooth Type

                 Teeth Number  Canal Number            Short
                                             [less than or equal to]2 mm

Upper Molars           15           46                  34
                                                        14.7%
Lower Molars           41          129                  60
                                                        25.9%
Upper Incisors         70           70                  48
                                                        20.7%
Lower Incisors         36           37                  24
                                                        10.3%
Upper Premolars        43           67                  42
                                                        18.1%
Lower Premolars        41           41                  24
                                                        10.3%
Total                 246          390                 232
                                                       100%

                          Length of root
                          canal filling
                  Short    Over Filling   Flush
                  >2 mm

Upper Molars        7            2          3
                    9.2%         7.4%       5.5%
Lower Molars       38           11         20
                   50.0%        40.7%      36.4%
Upper Incisors      8            1         13
                   10.5%         3.7%      23.6%
Lower Incisors      2            5          6
                    2.6%        18.5%      10.9%
Upper Premolars    13            5          7
                   17.1%        18.5%      12.7%
Lower Premolars     8            3          6
                   15.5%        11.1%      10.9%
Total              76           24         58
                  100%         100%       100%

TABLE 2. The frequency and percentage of the density of root canal
fillings according to the tooth type

                   Tooth Type    Density of root canal filling
                 Teeth   Canal            No Voids  Voids
                 Number  Number

Upper Molars       15       46             12        34
                                            6.1%%    17.7%
Lower Molars       41      129             69        60
                                           34.8%     31.2%
Upper Incisors     70       70             38        32
                                           19.2%     16.7%
Lower Incisors     36       37             21        16
                                           10.6%      8.3%
Upper Premolars    43       67             38        29
                                           19.2%     15.1%
Lower Premolars    41       41             20        21
                                           10.1%     10.9%
Total             246      390            198       192
                                          100%      100%

TABLE 3. The frequency and percentage of the taper of root canal
fillings according to the tooth type

                   Tooth Type    Taper of root canal filling
                 Teeth   Canal   Consistent  No consistent
                 Number  Number    taper       taper

Upper Molars        15     46       21          25
                                     9.4%       15.1%
Lower Molars        41    129       69          60
                                    30.8%       36.1%
Upper Incisors      70     70       37          33
                                    16.5%       19.9%
Lower Incisors      36     37       25          12
                                    11.2%        7.2%
Upper Premolars     43     67       44          23
                                    19.6%       13.9%
Lower Premolars     41     41       28          13
                                    12.5%        7.8%
Total              246    390      224         166
                                   100%        100%

TABLE 4. Evaluation of root canal fillings as acceptable or
unacceptable according to the tooth type

                   Tooth Type    Acceptable  Unacceptable
                 Teeth   Canal
                 Number  Number

Upper Molars       15      46       15          31
                                     3.8%        7.9%
Lower Molars       41     129       39          90
                                    10.0%       23.1%
Upper Incisors     70      70       28          42
                                     7.2%       10.8%
Lower Incisors     36      37       13          24
                                     3.3%        6.2%
Upper Premolars    43      67       18          49
                                     4.6%       12.6%
Lower Premolars    41      41       14          27
                                     3.6%        6.9%
Total             246     390      127         263
                  100%    100%      32.6%       67.4%

TABLE 5. The frequency and percentage of acceptable criteria among all
teeth

            Length   Density  Taper

Frequency   232      198      224
Percentage   59.48%   50.76%   57.43%

TABLE 6. The detailed results of the Kruskal--Wallis test to evaluate
the association between the quality of root canal filling criteria and
tooth type

                         Quality of root canal filling
Tooth Type           Length           Density          Taper
                  Mean   P-value   Mean   P-value   Mean   P-value
                  Rank             Rank             Rank

Upper Molars     164.96           243.63           218.48
Lower Molars     217.60           190.20           203.20
Upper Incisors   182.81           188.04           204.43
Lower Incisors   192.57   0.031   183.82   0.020   175.74   0.094
Upper Premolars  187.47           183.96           179.44
Lower Premolars  197.66           199.38           174.33

TABLE 7. The detailed results of the Mann--Whitney test to compare the
length and density of root canal filling among all tooth types

Tooth type       Length
                 Density
                 P-value
                 P-value

Upper molars      0.002
Lower molars      0.001
Upper molars      0.200
Upper premolars   0.001
Upper molars      0.108
Lower premolars   0.029
Upper molars      0.373
Upper incisors    0.003
Upper molars      0.217
Lower incisors    0.005
Lower molars      0.047
Upper premolars   0.668
Lower molars      0.291
Lower premolars   0.600
Lower molars      0.024
Upper incisors    0.914
 Lower molars     0.244
Lower incisors    0.726
Upper premolars   0.602
Lower premolars   0.424
Upper premolars   0.736
Upper incisors    0.776
Upper premolars   0.813
Lower incisors    0.997
Lower premolars   0.439
Upper incisors    0.577
Lower premolars   0.827
Lower incisors    0.484
Upper incisors    0.702
Lower incisors    0.808
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Title Annotation:ORIGINAL ARTICLE
Author:Habib, Adnan Asaad; Doumani, Mazen Deib; Nassani, Mohammad Zakaria; Shamsy, Enass; Jto, Basma Safwan
Publication:European Endodontic Journal
Date:Jul 1, 2018
Words:4461
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