|Year : 2018 | Volume
| Issue : 1 | Page : 1-6
Quality of root canal treatment of molar teeth provided by Saudi dental students using hand and rotary preparation techniques: Pilot study
Kholod Khalil Almanei
Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
|Date of Web Publication||10-Jan-2018|
Dr. Kholod Khalil Almanei
Department of Restorative Dental Science, College of Dentistry, King Saud University, P.O. Box 32306, Riyadh 11428
Source of Support: None, Conflict of Interest: None
Aim: To compare the quality of root canal treatment provided by dental students in relation to different root canal preparation techniques.
Materials and Methods: A pilot study was conducted at King Saud University. Root canal treatments of 46 molar teeth performed by 23 female dental students were included in this study. Each student prepared two molars teeth, first molar prepared with stainless steel (SS) hand K-files using step-back technique and the other molar prepared with ProFile rotary nickel-titanium (NiTi) files in a crown-down manner. Preoperative, working and postoperative periapical radiographs were assessed to evaluate the quality of root canal treatment based on the following criteria; obturation length, density, taper and presence of procedural errors. The data were statistically analyzed using exact conditional logistic regression test and the level of significance was set at 0.05.
Results: The percentage of root canal treatment with adequate length was better with the use of NiTi rotary instruments (65.5%) compared to SS hand files (34.5%). No difference between the obturation density and taper in both techniques (P = 1.000) (P = 0.6875). The incidence of procedural errors in teeth prepared with SS hand files (68.2%) was significantly more frequent compared with NiTi rotary group (31.8%). There was a statistically significant relationship between overall quality of root canal treatment and endodontic preparation techniques (P = 0.0386).
Conclusion: The quality of root canal treatment performed by King Saud University undergraduate dental student was significantly better in teeth prepared by NiTi rotary filing technique than teeth instrumented with SS hand file.
Keywords: Nickel-titanium rotary file, obturation quality, procedural errors, root canal treatment, stainless steel hand file
|How to cite this article:|
Almanei KK. Quality of root canal treatment of molar teeth provided by Saudi dental students using hand and rotary preparation techniques: Pilot study. Saudi Endod J 2018;8:1-6
|How to cite this URL:|
Almanei KK. Quality of root canal treatment of molar teeth provided by Saudi dental students using hand and rotary preparation techniques: Pilot study. Saudi Endod J [serial online] 2018 [cited 2018 Apr 22];8:1-6. Available from: http://www.saudiendodj.com/text.asp?2018/8/1/1/222759
| Introduction|| |
The primary aim of root canal treatment is to remove all the pulp tissues, bacteria and their by products, as well as to seal the entire root canal system and prevent microbial recontamination. Adequate cleaning and shaping of root canal system is the most crucial step for successful root canal treatment. This necessitates a full understanding of the canal morphology and respects of the canal curvature. However, preparation of narrow and curved canals can be challenging with possible procedural accidents such as creation of zips or elbows. Traditionally, stainless steel (SS) hand files have been used for root canal preparation; however, the inherent stiffness of these files plays a major role in the creation of canal aberrations. To overcome the iatrogenic procedural errors associated with SS files such as zipping, ledging, root canal perforation and straightening of the curved canal, nickel-titanium (NiTi) files were introduced. These files are superelastic, which is a unique property that allows them to be placed in curved canal with less lateral force than SS files. In addition to their greater flexibility, the occurrence of canal procedural errors was found to be less frequent compared to hand SS files.,,,, Finally, these files have the ability to prepare root canals in a shorter time than SS files.,,
The prognosis of root canal treatment has been shown to be significantly associated with the technical quality of root canal treatment.,, Radiographic evaluation of postobturation radiograph represents a very common method to assess the technical quality of root canal fillings. Several studies have demonstrated the strong correlation between adequate root canal treatment and the incidence of posttreatment disease.,,, Radiographic technical quality of root canal treatment is determine by multiple variables such as the length of the root canal filling material in relation to the radiographic apex, the density of the root filling material (presence of voids), the taper of the canal filling and the incidence of procedural errors. A number of studies have studied the success rate of root canal treatment performed by dental students using standard hand step-back canal preparation technique followed by lateral condensation for canal obturation.,,,,, The result of these studies indicated that the quality of root canal treatment was considered as unsatisfactory and the modification of the preclinical and clinical program was recommended.
With the revolution of the NiTi rotary files, there is growing trend toward teaching the rotary preparation technique at the undergraduate level in dental schools. To date, limited studies have examined the quality of root canal treatment performed by undergraduate dental students using NiTi rotary files., The use of NiTi rotary instruments was recently introduced in the undergraduate dental curriculum of King Saud University. There is no study yet addressed the quality of root canal treatment of undergraduate students in Saudi Arabia done by NiTi rotary instruments. Hence, the aim of this study was to evaluate the quality of root canal treatment performed by undergraduate students at King Saud University using SS hand versus NiTi rotary technique.
| Materials and Methods|| |
Ethical Committee of College of Dentistry Research Center, King Saud University, Saudi Arabia, approved the design of this pilot study. Twenty-three female dental students registered in the Bachelor of Dental Science Program during the school year 2014 at school of dentistry in King Saud University were enrolled in this study. The selected students had successfully completed 1 year preclinical endodontic training on natural teeth using SS hand and NiTi rotary preparation techniques. During the clinical endodontic program, the students had finished the root canal treatments of two anterior and two premolar teeth using hand and rotary techniques.
Forty-six teeth comprising of maxillary and mandibular first and second molars requiring primary nonsurgical root canal treatment were included in this study. All selected teeth had minimum to moderate difficulty in accordance to American Association of Endodontics (AAE) endodontic case assessment form. Each student had been asked to shape two molar teeth, first molar with SS hand files using step-back technique and the other molar with rotary NiTi files in a crown-down manner.
All teeth were pre-examined radiographically and treated by following protocol:
Local anesthesia was administered, after that access cavity was prepared under rubber dam isolation and temporary build up was done for destructed teeth. Working length was determined with the aid of an electronic apex locator (Root ZX, J. Morita USA, Inc., Irvine, CA, USA) and confirmed by periapical conventional radiograph. Straight-line access was established by Gates-Glidden burs no. 2, 3 and 4 (Premier Dental, Norristown, PA, USA).
The teeth were randomly selected and divided into two groups according to preparation techniques.
Group 1: Stainless-steel hand files preparation technique
A total of 23 teeth were prepared by conventional SS K-files (Dentsply, Tulsa, Okla, USA) of 0.02 taper using the traditional step-back preparation technique. Apical preparation was finished with file sizes 35K or 40K (master apical file). After determining the master apical file, the succeeding larger files were shortened by 0.5 or 1.0 mm increments from the previous file length; the preparation is completed up to the coronal part of the canal.
Group 2: Nickel-titanium rotary files preparation technique
After establishing of a smooth glide path using SS K-files size 20, the canals were prepared by ProFile rotary instruments (Dentsply-Maillefer, OK, USA) connected to an X-smart motor (Dentsply-Maillefer). Two kits of ProFile rotary files, each kit contains 6 files with different sizes (15, 20, 25, 30, 35, 40), 0.04 and 0.06 taper were used in crown-down technique started with large taper. Apical preparation was finished with 0.04 taper sizes 35 or 40. During the canal preparation, all root canals were irrigated with 1% sodium hypochlorite solution and the files were coated with lubricant (Glyde ™ File Prep Root Canal Conditioner, Dentsply-Maillefer, Ballaigues, Switzerland). Root canals of all groups were filled with standard gutta-percha points and AH26 sealer (Dentsply-Maillefer, OK, USA) using cold lateral condensation technique.
Radiographic evaluation criteria
Preoperative, working and postoperative periapical radiographs which taken by parallel technique with Kodak Ultra-speed D films (Carestream Health, Inc., Rochester, NY, USA) were evaluated by senior endodontist (with 7 years experience). Radiographs were mounted in cardboard slit to block ambient light from entering the illuminated viewing box (Star X-ray Illuminator; Star X-ray, Amityville, NY, USA) and examined under ×2 magnification with a magnifier.
The technical quality of root canal treatment was examined according to the criteria described by Barrieshi-Nusair et al., including the obturation length, density, and taper. The length of each root canal filling was categorized as adequate, short and overfilled based on their relationship with the radiographic apex. Density and taper of filling was evaluated based on the presence of voids and the uniform tapering of the filling, respectively. In addition presence of procedural errors such as; transportation, ledge, perforation and separated instrument was examined. The radiographic evaluation was based on the root that had the poorest quality of canal filling.
The statistical analysis was performed using SAS software (Version 9.3, SAS Institute Inc., Cary, NC, USA). The five evaluation criteria, obturation length, density, taper, presence of procedural errors and overall quality, were binary. To take into account the matched-pairs design, exact conditional logistic regression  was proposed to analyze the small set of binary data. The exact conditional score tests were used to test if an effect was statistically significant. P < 0.05 indicated that an effect was statistically significant at the 0.05 level of significance. The odds ratio was estimated for the independent variables and the corresponding 95% confidence intervals were also computed.
| Results|| |
Results are summarized in [Table 1] and [Table 2].
|Table 1: Two-way frequency tables of endodontic preparation techniques and the outcome variables of interest, obturation length, obturation density, obturation taper, procedural errors and overall quality|
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|Table 2: Exact conditional score tests of the effect of preparation techniques (stainless steel hand vs. nickel-titanium rotary) on the quality of root canal treatment|
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The percentage of root canal treatment with adequate length was better with the use of NiTi rotary instruments (65.5%) compared to SS hand files (34.5%). There is no difference between the obturation density and taper in both instrumentation techniques [Table 1]. The incidence of procedural errors in teeth prepared with SS hand files (68.2%) was significantly more frequent compared with NiTi rotary group (31.8%).
The results of the exact conditional score tests [Table 2] indicated that there was a statistically significant relationship between obturation length, presence of procedural errors and endodontic preparation techniques at the 0.05 level of significance (P = 0.0225) (P = 0.0386). On the other hand, there was no statistically significant relationship between obturation density, obturation taper and endodontic preparation techniques at the 0.05 level of significance (P = 1.000) (P = 0.6875). However, there was a statistically significant relationship between overall quality of root canal treatment and endodontic preparation techniques at the 0.05 level of significance (P = 0.0386).
| Discussion|| |
Nowadays, many universities are adopting the use of NiTi rotary preparation technique as a part of their undergraduate endodontic curriculum. Various studies have assessed the procedural errors and complications associated with NiTi instruments when used by dental students.,,, These studies showed superior performance of NiTi files in maintaining the original canal shape with less procedural errors. However, few studies have been investigated the technical quality of root canal treatment performed by undergraduate students using NiTi instrumentation technique in compared with standard SS hand technique., This was not carried out in a Saudi university yet.
In the present study, experienced endodontist was asked to evaluate the quality of root canal treatment. Trained and experienced endodontists usually chosen to evaluate the technical quality of root canal treatment., In fact, differences in specialty training and experience strongly influence endodontic agreement and decision making.
The percentage of root canal treatment with adequate length in this study was 65.5% with NiTi rotary technique and 34.5% in SS hand group. This frequencies were inferior to those reported by Robia  and Anayat et al. (90%-60%). This difference in the results could be referred to the operator experience. Indeed, the endodontic treatment in this study was provided by undergraduate students, where in the previous studies, the root canal treatment was carried out by postgraduate students, residents and endodontic consultants. This proved by epidemiological studies that showed a significant difference in the result of endodontic treatment between well trained endodontic specialists and general practitioners.,
Adequate density of root canal filling is an important factor for long-term success of endodontic treatment., Hence, adequate density will prevent microleakage along root canal filling and decrease the prevalence of apical periodontitis. The results of the present study revealed that adequate density of root canal filling was 48.7% and 51.3% in teeth prepared with NiTi rotary and SS hand filling techniques respectively. These finding indicated that there was no significant difference in the obturation density and root canal preparation techniques. This result was in contrast to the findings of previous studies,, which reported that adequate density was achieved in 83%–85% of cases prepared with rotary and 37.5%–47% of cases prepared by SS hand instruments. These discrepancies in the results could be due to the use of greater taper gutta perch points for obturation the group prepared with rotary. However, in this study both groups were obturated using standard gutta perch point (0.02 taper) with cold lateral condensation technique.
In this study, no significant association was detected between the obturation taper and the filing techniques. However, Robia  and Anayat et al. demonstrated that the obturation taper was significantly higher in teeth prepared by NiTi rotary instruments than those prepared with manual technique. This difference in the results could be explained by the fact that the obturation taper was dependent on the root canal preparation technique and instrument taper. In the current study, smaller taper instrument (ProFile 0.4) was used for NiTi group, whereas previous studies used a greater taper (Protaper) system for canal preparation in rotary preparation group.
Presence of procedural errors (transportation, ledge, perforation, and instrument separation) caused inadequate instrumentation and/or obturation of root canal system. The incidence of procedural errors in teeth prepared with SS hand files (68.2%) was significantly more frequent compared with NiTi rotary group (31.8%). This was in constant with the finding of other studies Pettiette et al. and Gluskin et al. who reported that undergraduate dental students had less procedural errors in root canals prepared with NiTi files compared to canals prepared with SS hand instruments.
The results of this study showed that the frequency of teeth with acceptable root canal treatment was significantly greater in NiTi rotary group (66.7%) than SS hand group (33.3%) (P = 0.0386). These findings were in agreement with the conclusions of earlier studies done by Abu-Tahun et al. and Donnelly et al. who demonstrated that the technical quality of root canal treatment in multi-rooted teeth performed by dental students using NiTi rotary files was significantly better than the teeth prepared with hand instruments.
| Conclusion|| |
Regardless of the small number of students evaluated, the obtained results showed that the quality of root canal treatment performed by King Saud University undergraduate dental student was better in teeth prepared by NiTi rotary filing technique than by SS hand preparation technique.
The study was registered in College of Dentistry Research Center as nonfunded research (registration ID: 0151) King Saud University, Riyadh, Saudi Arabia.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]