962 D3000 new imprint Word template Vol 13, No 1 (2025) ISSN 2167-8677 (online) DOI 10.5195/d3000.2025.962 http://dentistry3000.pitt.edu Radiographic Quality of Root Canal Therapy Accomplished Clinically by Undergraduate Dental Students Thulficar Ghali Hameed Al-Khafaji1, Azal Al-Masoody2, Qasim Abdulkareem Mohammed1, Zainab Mahmood Al-Jammali1, Mays Ali Azeez Alanz3 1College of Den*stry, University of Babylon, Hilla, Iraq 2College of Den*stry, University of Alkafeel, Najaf, Iraq 3Iraqi Ministry of Health, Babylon, Iraq Abstract ObjecBve: To analyze the technical quality of root canal therapy done by dental students while in clinical training. Material and Methods: The frequency of common technical er- rors was assessed using dental periapical radiographs. 870 charts (n= 870) were evalu- ated which involved 870. In each chart, 3 periapical radiographs were used for evalua- tion of the incidence rate and types of errors happening within the root canal procedure. The 3 periapical radiographs were diagnostic (pre-treatment) radiograph, working length determination radiograph, and gutta-percha and sealer (obturation) radiograph. Results: It was found that phase 3 (obturation phase) shows the highest frequency of er- rors 54.37%, followed by phase 1 (access opening) 11.84%, and Jinally phase 2 (root canal preparation) shows the least frequency 4.01%. Conclusion: This study idenDfied that the least rate of errors in endodonDc therapy happened during access opening and instru- mentaDon when compared to obturaDon. Open Access Cita%on: Al-Khafaji TGH, et al. (2025) Radiographic Qual- ity of Root Canal Therapy Accomplished Clinically by Un- dergraduate Dental Students. Den%stry 3000. 1:a001 doi:10.5195/d3000.2025.962 Received: June 14, 2025 Accepted: June 26, 2025 Published: August 13, 2025 Copyright: ©2025 Al-Khafaji TGH, et al. This is an open access ar%cle licensed under a Crea%ve Commons AUrib- u%on Work 4.0 United States License. Email: dent.thulficar.ghali@uobabylon.edu.iq Introduc)on In the school of dentistry, one of the im- portant requirements that should be done by the undergraduate students is the root canal therapy (RCT) [1]. This treatments in- volves cleaning, shaping and appropriate filling of the radicular space [2]. The main aim of the RCT is to allow healing of the per- iapical tissues surrounding the root of the tooth and prevent the re-infection of the radicular space [3]. The outcome of the en- dodontic treatment mainly rests on the quality of the procedural technique of the root canal filling (RCF) [4,5]. The common method that has been implemented to judge the quality of the root canal fillings is peri- apical radiographs during the different phases of the root canal therapy [6-8]. The successful root canal therapy (RCT) pre- vents tooth pain. It should also reduce the risk of tooth loss and/or developing apical periodontitis [9]. Dentists should remember that in each phase of the treatment, any op- erative mistake may have negative effect on prognosis, as these mistakes increase the risk to failure of the entire treatment [9]. According to previous research, errors dur- ing RCT can be divided into three groups ac- cording to the treatment phase as follows [10-14]: Phase 1 (Access opening errors): • Gouging • Coronal perforation • Over preparation Phase 2 (Cleaning and preparation errors): • Ledge • Transportation "zipping" • Strip perforation • Broken instruments • Apical perforation Phase 3 (Root canal obturation errors): • Void • Over-filling • Under-Jilling Usually, the evaluation of the RCT technical quality is based on careful radiographic ex- amination [6,15-17]. Therefore, the current study assessed radio- graphically the quality of endodontic ther- apy done by undergraduate students through these 3 phases of treatment, while in their clinical training. The frequency of com- mon technical errors was evaluated by mul- tiple dental periapical radiographs. Material and Methods This study was done at the dental school, University of Babylon, Iraq. It was done in Radiographic Quality of Root Canal Therapy Accomplished Clinically by Undergraduate Dental Students Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.962 http://dentistry3000.pitt.edu 2 agreement with the 1964 Declaration of Hel- sinki and its succeeding revisions. The root canal therapy was performed by under-grad- uate students in their Jifth year of study in the clinics of the dental school under the su- pervision of qualiJied supervisors (endodon- tists). The RCT was performed on single-root canal treated teeth on upper and lower inci- sors, canines, and premolars, during 6-year period from October 2014 to October 2020. The single-root canal teeth were endodonti- cally treated, Jirstly access opening was done into the pulp space of the tooth and the den- tal pulp was extirpated, and then the root ca- nal system was instrumented by K-Jiles (Dentsply, Maillefer, Switzerland) with a 0.02 taper. The conventional step-back tech- nique was applied. Canals irrigation was per- formed using normal saline and an endodon- tic gauge 27 syringe. Obturation of the canals was then performed by cold lateral compac- tion technique using standardized gutta-per- cha cones (Dentsply Maillefer, Switzerland) and a ZOE-based endodontic sealer (EndoJill, Dentsply, Brazil). In this study, 870 charts (n= 870) were eval- uated which involved 870. In each chart, 3 periapical radiographs were used for the evaluation of the executed endodontic pro- cedures in terms of types and incidence of er- rors. The 3 periapical radiographs were di- agnostic (pre-treatment) radiograph, work- ing length determination radiograph, and gutta-percha and sealer (obturation) radio- graph. Two qualiJied dentists (two endodon- tists) assessed these radiographs on a light box x-ray viewer in dark environment [11]. A comparative evaluation between these ra- diographs was used to verify any errors that could have occurred during the phases of the root canal therapy. The applied parameters in this study were: no-fault cases; where there was no detected procedural mistakes and gutta percha is shorter than the radio- graphic apex by less than 2 mm, coronal-per- foration, over preparation, gouging, strip perforation, apical perforation, broken in- struments, ledging, transportation, void in the Jilling material, overJilling, and under Jill- ing of guttapercha [10,11]. Before conducting this study, Intra- and in- ter-examiner agreements were veriJied by values calculation of Cohen's Kappa (k) using 35 randomly chosen periapical radiographs that had been used in this study [18]. The re- sults were 0.88 and 0.81, respectively, so both values indicated excellent intra- and in- ter-examiner agreements. Finally, SPSS soft- ware (version 20.0, SPSS Inc., Chicago, IL, USA) was implemented for the processing of data. Pearson’s chi-square test was applied to analyze the data at P<0.05. Results Table 1 shows that 70.33% of cases have var- ious types of errors, but 29.77% of them have no error (normal). The various types of errors in phase 1 are 4.48% gouging and 7.36% over preparation, in phase 2 are 1.26% ledge, 0.8% strip perforation, 0.69% broken instruments and 1.26% apical perfo- ration, and in phase 3 are 12.99% void, 4.83% overJilling and 36.55% underJilling. It seems that the dominant type of error is the underJilling which shows the highest fre- quency, followed by void, over preparation, overJilling then gouging. While, ledge, apical perforation, strip perforation and broken in- struments show tiny frequencies. However, the difference between all types of were sig- niJicantly different, P<0.05, table 2. It also seems that phase 3 (obturation phase) shows the highest frequency of errors 54.37%, followed by phase 1 (access open- ing) 11.84%, and Jinally phase 2 (root canal preparation) shows the least frequency 4.01% (Table 1). Discussion The accurate chemo-mechanical cleaning and shaping of the dental root canal could re- sult in successful RCF. Any error happens during the 3 phases of the root canal therapy could affect the prognosis. In dental schools, the undergraduate students should be taught about these errors to avoid any tech- nical error that could happen during the RCT and to improve the prognosis of the RCT. This study paid close attention to the assess- ment of the quality of the RCT whether the treatment was without error (normal) or with error during all phases of the RCT. The periapical radiographs were utilized to eval- uate the success of root canal therapy in pa- tients operated by the 5th year under-gradu- ate students at the dental school clinics of University of Babylon. Several studies have evaluated the errors, such as gouging, ledges, apical perforation, broken instruments, underJilling, overJilling and voids which could happen during RCT treatment [10,11,16,19]. In this study, errors occurred during all the phases of the RCT, but the most frequent errors were during the third phase (obturation phase). This was fol- lowed by phase 1 (access opening), whereas phase 2 (root canal preparation) recorded the least frequency of errors. In phase 3, the underJilling error showed the highest incidence. This could be attributed to the debris accumulating at the apical third of the root canal due to instrumentation with- out enough irrigation of the canal which could result in shortening of the working length and Jinally results in underJilling. The other possible reason for the underJilling, is the non-complete instrumentation of the root canal which could happen from the wrong measurement of the root canal length [20]. Again, in phase 3, voids error was the next higher incidence, in which spaces could form between the gutta-percha cones. These voids might harbor pathological microorganisms. These voids could be due to not-enough con- densation of the gutta-percha cones into the radicular canals [21]. In addition, the non- homogeneous mixing of the endodontic sealer could also result in theses voids [22]. Finally in phase 3, the overJilling was with the least frequent error. it could have been the result of over-estimation of working length of root canal, which could end in loss of the apical stop. Generally, it has been agreed that root canal Jilling is preferred to be within 2 mm distance away from the radi- ographic apex [6,23]. Higher success rates of RCF were associated in teeth Jilled with root canal Jilling ≤ 2 mm short from the radio- graphic apex with decreased occurrence of apical periodontitis in comparison with teeth Jilled > 2 mm away from the radio- graphic apex [24]. According to this study, the quality of the endodontic therapy that is offered for the patient by undergraduate stu- dents is not good enough. This result is sup- ported by the results of three previous stud- ies [10,16,25]. Improving knowledge, training and skills of the undergraduate students is very im- portant. This can be done by improvement of several factors such as increasing the ratio of supervisors to students and improvement of the training aids of the undergraduate stu- dents, in addition to introduction of different methods for evaluation the work of the stu- dents. Conclusions This study identiJied that the access opening phase and instrumentation phase in root ca- nal therapy have less incidence of errors when compared with the obturation phase. Whereas, in obturation phase, the errors which recorded the highest incidence rate were underJilling, voids and then overJilling. Consequently, it is advised to enhance the practical training sessions of the RCT, espe- cially in the last phase (obturation phase). Ethical Approval This study was reviewed and approved by the Research Ethical Approval Committee of the Dental School of the University of Baby- lon (Babylon, Iraq), with reference number (27) on (29/5/2024). 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Type of error Number (%) No Error (Normal) 259 (29.77%) Phase 1 (Access opening) Gouging 39 (4.48%) 11.84% 70.33% Over preparation 64 (7.36%) Phase 2 (Preparation) Ledge 11 (1.26%) 4.01% Strip perforation 7 (0.80%) Broken instruments 6 (0.69%) Apical perforation 11 (1.26%) Phase 3 (Obturation) Void 113 (12.99%) 54.37 Over Jilling 42 (4.83%) Under Jilling 318 (36.55%) Total 870 (100%)