Cleanliness of the root canals after preparation with Endostar E3 rotary instruments
26 апреля 2021 0:00
// Endostar
A scanning electron microscopic studies
Root canal preparation with the use of nickel‑titanium instruments is currently the gold standard in endodontic treatment. Rotary instrument systems earned their unquestionable popularity thanks to shortening the amount of time needed to prepare the canal, their flexibility and resistance to breakagean advantage brought by using a nickel‑titanium alloy and the instrument’s design. For most systems currently available on the market, the preparation process of the canal starts with shaping the coronal third first, the middle third second and the apical third last. Such protocol is called the crown‑down method and has many advantages. Preparation of the coronal third and later the middle third of the canal, provides an easier i.e. more straight‑lineaccess to the apical part of the canal, this way avoiding uneven widening of the apical third, ledges and breaking of instruments. Furthermore, when pulp and dentin of the canal are infected, these instruments guarantee that all these tissues are removed before preparation of the apical portion of the canal.
This limits the risk of pushing infected debris beyond the apex. (1‑4). Polish literature provides little research, which would evaluate the cleanliness of root canals after rotary nickel‑titanium instrument preparation. Evaluation is usually performed with the use of a surgical microscope (5‑8), however there are papers which analyse cleanliness based on results obtained from a scanning electron microscope (9,10). The latter have an advantage of being able to detect small debris particles and a smear layer, apart from the presence of larger particles of debris (dentine particles and pulp remnants) which are seen under a surgical microscope.
This layer is created when the instrument touches the dentine (friction force of the instrument applied to the wall of the canal). It takes the form of a thin amorphous structure composed of dentine particles, pulp remnants, bacteria and their metabolites, solutions used to rinse the canal and even parts of the material from which the tools are made. According to recent standards, the smear layer should be removed since it may, among others, hinder disinfection of the canal (infected root canals) and later cause leakage of the filling (3,4, 11‑15). Endostar E3 (Poldent) is one of the many rotary nickel‑titanium systems available on the Polish market. In contrast to conventional rotary file systems, the Endostar E3 Basic system (fig.1) is composed of three instruments which can be used in preparation of most root canals. These files have two cutting edges which provide effective dentine cutting power and an inactive, non‑cutting tip, which significantly limits the creation of ledges and perforations.
Aim and objectives
The aim of the paper was to evaluate the cleanliness of the walls of root canals prepared with the use of the Endostar E3 Basic system.
Materials and methods
Research material and canal preparation In order to be able to compare the results with other observations (9,10), the same method was used as in the cited literature (among others the same rinsing solutions, lubricants, research material‑similar root canal morphology and cleanliness evaluation criteria).
The study used 8 disto‑buccal roots of the maxillary molars, which did not undergo endodontic treatment, had fully formed apexes and were not damaged (without cracks or resorption cavities). After access to the pulp chamber was created, the canal orifices were widened and working length was established. In order to perform this, a size 10 K‑file was inserted into the canal until the apex of the file became visible through the anatomical foramen. Working length was established by subtracting 1 mm from this length. Next, the initial apical file length was stablished, this way qualifying canals sized ISO 15 for this study (a #15 K‑file was inserted to the canals at working length until a tug‑back sensation was achieved).The Endostar E3 Basic instruments, which were mounted onto the Endostar ProEndo (Poldent) handpiece (fig. 2) were used to prepare the canal. The canal orifice and coronal portion of the canal were shaped with the use of instrument no. 1 (30/08; the instrument with one blue stripe). The in‑strument was inserted no more than to half of the root canal length. Next, hand K‑files were used to widen the apical part of the canal to size ISO 20, which was followed by widening the canal with the following‑size rotary file (instrument no 2. 25/06, two red stripes on the handle). This instrument was inserted to a maximum ⅔ of the root canal length and an up‑down motion was applied. Recapitulation with the size 15 K‑file was performed by inserting the tool at full working length. This was followed by shaping the apical portion of the canal, which was done with instrument no. 3 (30/04; the instrument with three blue stripes). Whenever the size of the file was upgraded, the canals were irrigated with 2 mL of 2.5% sodium hypochlorite solution, which was applied through a syringe and size 30 endodontic needle with a foramen at the apex (the needle was inserted 1.5 ‑ 2 mm shorter than maximum preparation length), File‑ Eze (Ultradent) was used as a lubricant. 5 L of distilled water was used for final irrigation and standardized paper points (Poldent) were used to dry the canal.
Observations in the SEM
After performing circular cuts r on the roots of the teeth (at the level of the cervix) with a flame‑shaped bur, the roots were broken off. This was followed by forming longitudinal
fissures on the the lingual and buccal surfaces with the same burr. Next, the roots were cut in half in order to make the lumen of the canal visible. Wire‑cutting pliers were used to crack the root apart. The better preserved of the two was qualified for further testing. The samples were dehydrated with ethanol, dried in the critical point and a layer of AuPd40 was sprayed on. The inner surfaces of the canals were analyzed in the scanning electron microscope JEOL 6100 (Jeol) and magnified 200 times, which showed pulp remnants and dentine debris. The smear layer was evaluated at 1000x magnification. Evaluation of randomly chosen microscopic fields was performed in the coronal, middle and apical thirds of the roots, separately for debris and the smear layer using the criteria first described by Hulsman et al. (16).
A 5‑category scale was used to perform debris evaluation:
Category 1 ‑ the wall of the root canal is clean, only a some debris is visible,
Category 2 ‑ single, small agglomerations of debris,
Category 3 ‑ numerous agglomerations of debris, however covering less than 50% of the surface of the wall the root canal,
Category 4 ‑ more than 50% of the wall of the root canal is covered by debris,
Category 5 ‑ the wall of the root canal is completely or almost completely covered with debris.
A 4‑category scale was also used to evaluate the semar leyer:
Category 1 ‑ no smear layer, open dentinal tubules,
Category 2 ‑ small amount of smear layer, part of the dentinal tubules remain open,
Category 3 ‑ the surface is covered with a homogenous smear layer, only singe dentinal tubules remain open,
Category 4 ‑ the wall of the root canal is completely covered with a homogenous smear layer, no open dentinal canals,
Category 5 ‑ copious, nonhomogenous smear layer completely covering the wall of the root canal.
Statistical analysis
Statistical analysis was performed with the Fisher’s exact test. Statistical significance was defined at p < 0.05.
Results
The results of the analysis carried out in 200x magnification were presented in Table 1 and in Figure 3. The walls of the root canals were usually clean ( category 1 ), although segments covered with debris were also observed ( category 2‑ 5). Statistical analysis did not show significant differences between individual segments in the canal.
The results of the analyses carried out in 100x magnification were presented in table 2 and figure 4. The smear layer which emerged as a result of cutting the dentine with the
Endostar E3 tools, was relatively copious and completely covered the roots surface (category 5). Categories 1 to 4 were more rarely assigned. As in the previous case, no statistical significance was seen between individual segments of the canal.
Discussion
The aim of the mechanical (biomechanical) preparation of the root canal is to model it to a certain size and shape that would allow efficient irrigation and later its proper filing throughout its entire length without pushing the material into the periapical area. Apart from proper shaping of the canal it is extremely important to remove the contents of the canal and debris generated during cleaning (3,4).
According to many publications, rotary file systems lets us prepare the canal without losing its natural shape and providing good cleaning of the canal (1, 9, 10, 17‑20). In comparison with the hand‑held instruments, they provide better cleaning in a significantly much shorter time, however do not guarantee an ideal effect.
The aim of our own study was to evaluate the cleanliness of the walls of the root canals prepared with the Endostar E3 system. In order to compare the obtained results with the previous observations, a methodology very similar to those in the cited papers was used (9, 10). Sodium hypochlorite was used for irrigation. A chelating solution was not used, only a gel consisting sodium versenate was applied. SEM observations were made under the same magnifications (200x and 1000x) and evaluated with the same scale (Hulsman scale).
Observations of the debris created as a result of canal preparation with the help of the Endostar E3 system showed their small amount‑the walls were usually clean. Similar observations were made in previous studies which evaluated the cleanliness of root canals after preparations performed with the ProFile and Mtwo. The studies showed that the canals were also relatively clean and similar to the Endostar E3 system, no statistical difference was observed regarding the individual segments of the canal. This lets us conclude that with the use of the Endostar E3 instrument system, the cleanliness which is evaluated at 200x magnification is compared to the cleanliness of the canals prepared with the use of the ProFile and Mtwo systems. One must notice however, that this depends on the efficacy of irrigation (the volume of the solution, the irrigation technique and type of irrigant) (3, 4).
In our own study, the presence of a more or less homogenous smear layer was found during microscopic evaluation at large magnifications. Similar results were obtained in previous studies (9,10), although this was not the case in the ProFile system where the smear layer was smaller in the coronal part of the canal compared to the middle and apical parts. The differences between the amount of smear layer generated by the Endostar E3 and Mtwo file systems compared with the ProFile are probably the result of the selection of research material. The study which evaluated the efficacy of the ProFile instruments used single‑root premolars. In premolars, the coronal part of the root canal is naturally bigger than the remaining two parts. Therefore, there is a smaller chance of the instrument touching this part of the canal resulting in a reduced smear layer. Whereas, in the studies evaluating the cleanliness of the canals after applying the Mtwo and Endostar E3 system, teeth with a similar root‑canal system morphology were used (mesial roots of mandibular molars and disto‑buccal roots of the maxillary molars vs. distobuccal roots of maxillary molars). These canals are relatively narrow and only slightly become wider in the direction of the pulp chamber. We can therefore assume that during preparation, the instruments contact the walls on a relatively large area, thus generating a more abundant smearlayer.
Similarly to the previous studies, a chelating solution was not used for irrigation. It was assumed that the use of such solution would dissolve the smear layer and this way hinder instrument and smear layer valuation. The presence of the smear layer in a certain area means that the instrument was in contact with that area.
To summarize, the cleanliness of the canals prepared with the use of the Endostar E3 system is similar to that observed in the ProFile and Mmtwo systems (lack of debris and a relatively copious smear layer).
References
1. Schäfer E., Erler M., Dammaschke T.: Comparative study on the shaping ability and cleaning efficiency of rotary Mtwo instruments. Part 2. Cleaning effectiveness and shaping ability in severely curved root canals of extracted teeth. Int. Endod. J., 2006, 39, 3, 203‑212.
2. Hülsmann M., Schäfer E.: Probleme in der Endodontie. Prävention. Identyfication and Management. Quintessenz, Berlin 2017.
3. Jańczuk Z., Kaczmarek U., Lipski M.: Stomatologia zachowawcza z endodoncją. Zarys kliniczny. PZWL, Warszawa 2014.
4. Arabska‑Przedpełska B., Pawlicka H.: Współczesna endodoncja w praktyce. Bestom, Łódź 2011.
5. Wilkoński W. i wsp.: Analiza porównawcza jakości opracowania kanałów korzeniowych za pomocą systemów rotacyjnych ProTaper i Mtwo oraz systemu recyprokalnego Reciproc – badanie in vitro. Porad. Stomatol., 2011, 115, 9, 340‑347.
6. Wilkoński W. i wsp.: Porównanie skuteczności opracowania kanałów korzeniowych instrumentami Reciproc 25 oraz ProTaper F2 z zastosowaniem techniki Ghassana Yareda – badanie in vitro. Mag. Stomatol., 2011, 21, 11, 144‑150, online.
7. Wilkoński W. i wsp.: Porównanie jakości opracowania kanałów korzeniowych techniką rotacyjną narzędziami Mtwo oraz techniką recyprokalną narzędziami Reciproc 25, ProTaper F2 oraz WaveOne Primary – badanie in vitro. Porad. Stomatol., 2011, 118, 11, 480‑487.
8. Wilkoński W. i wsp.: Analiza porównawcza jakości opracowania kanałów korzeniowych systemami narzędzi rotacyjnych K3 oraz HyFlex. Badanie in vitro. Mag. Stomatol., 2014, 24, 1, 126‑131, online.
9. Lichota D., Lipski M., Woźniak K.: Ocena czystości ścian kanałów korzeniowych opracowanych za pomocą narzędzi ProFile: badania w SEM. Czas. Stomatol., 2005, 58, 3, 151‑157.
10. Lichota D. i wsp.: Czystość ścian kanałów korzeniowych po opracowaniu rotacyjnymi narzędziami niklowo‑tytanowymi Mtwo: badanie w SEM. Ann. Acad. Med. Stetin., 2008,
54, 3, 58‑62.
11. Torabinejad M. i wsp.: Clinical implications of the smear layer in endodontics: a review. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod., 2002, 94, 6, 658‑666.
12. George S., Kishen A., Song K.P.: The role of environmental changes on monospecies biofilm formation on root canal wall by Enterococcus faecalis. J. Endod., 2005, 31, 12,
867‑872.
13. Yang S.E., Bae K.S.: Scanning electron microscopy study of the adhesion of Prevotella nigrescens to the dentin of prepared root canals. J. Endod., 2002, 28, 6, 433‑437.
14. Kokkas A.B. i wsp.: The influence of the smear layer on dentinal tubule penetration depth by three different root canal sealers: an in vitro study. J. Endod., 2004, 30, 2, 100‑102.
15. Saleh I.M. i wsp.: Bacterial penetration along different root canal filling materials in the presence or absence of smear layer. Int. Endod. J., 2008, 41, 1, 32‑40.
16. Hülsmann M., Rümmelin C., Schäfers F.: Root canal cleanliness after preparation with different endodontic handpieces and hand instruments: a comparative SEM investigation. J. Endod., 1997, 23, 5, 301‑306.
17. Zand V. i wsp.: A comparative SEM investigation of the smear layer following preparation of root canals using nickel titanium rotary and hand instruments. J. Oral Sci., 2007,
49, 1, 47‑52.
18. Jodway B., Hülsmann M.: A comparative study of root canal preparation with NiTi‑TEE and K3 rotary Ni‑Ti instruments. Int. Endod. J., 2006, 39, 1, 71‑80.
19. Prati C. i wsp.: Appearance of the root canal walls after preparation with NiTi rotary instruments: a comparative SEM investigation. Clin. Oral Investig., 2004, 8, 2, 102‑110.
20. Hülsmann M., Herbst U., Schäfers F.: Comparative study of root‑canal preparation using Lightspeed and Quantec SC rotary NiTi instruments. Int. Endod. J., 2003, 36, 11, 748‑756.
Mariusz Lipski1, Damian Lichota2, Włodzimierz Dura1, Ewa Marek1, AlicjaIntroduction
Nowicka2
1Department of Preclinical Conservative Dentistry and Preclinical Endodontics, Pomeranian Medical University of Szczecin. Head of the department: Mariusz Lipski DDS, PhD, e‑mail: lipam@pum.edu.pl
2Department of Conservative Dentistry, Pomeranian Medical University of Szczecin. Head of the department: Jadwiga Buczkowska‑Radlińska DDS, PhD
Abstract
Introduction. The aim of this in vitro study was to evaluate the cleanliness of root canal walls prepared using Endostar E3.
Material and methods. Eight disto‑buccal roots of maxillary molars were used in the study. The root canals were prepared using Endostar E3 Basic (Poldent) rotary nickel‑titanium instruments. Then the roots were split, and the canal walls were subjected to scanning electron microscopy. The presence of debris and smear layer were evaluated using a 5‑point scoring system and statistically analysed using Fisher’s test.
Results. The walls of the root canals were usually free from debris, although parts covered with debris were also observed to varying degrees. Statistical analysis did not show any significant differences between parts of the canals. However, the smear layer was relatively abundant, completely covering the surface of the root canals. Occasionally, areas with few open dentinal tubules were observed. Also in the case of the smear layer, statistical analysis did not show any significant differences between parts of the canals.
Conclusions. The Endostar E3 nickel‑titanium instruments ensure effective removal of debris. After the preparation of the canals, a relatively thick smear layer remains on their
walls.
Key words: root canal preparation, cleanliness, nickel‑titanium instruments, SEM
Root canal preparation with the use of nickel‑titanium instruments is currently the gold standard in endodontic treatment. Rotary instrument systems earned their unquestionable popularity thanks to shortening the amount of time needed to prepare the canal, their flexibility and resistance to breakagean advantage brought by using a nickel‑titanium alloy and the instrument’s design. For most systems currently available on the market, the preparation process of the canal starts with shaping the coronal third first, the middle third second and the apical third last. Such protocol is called the crown‑down method and has many advantages. Preparation of the coronal third and later the middle third of the canal, provides an easier i.e. more straight‑lineaccess to the apical part of the canal, this way avoiding uneven widening of the apical third, ledges and breaking of instruments. Furthermore, when pulp and dentin of the canal are infected, these instruments guarantee that all these tissues are removed before preparation of the apical portion of the canal.This limits the risk of pushing infected debris beyond the apex. (1‑4). Polish literature provides little research, which would evaluate the cleanliness of root canals after rotary nickel‑titanium instrument preparation. Evaluation is usually performed with the use of a surgical microscope (5‑8), however there are papers which analyse cleanliness based on results obtained from a scanning electron microscope (9,10). The latter have an advantage of being able to detect small debris particles and a smear layer, apart from the presence of larger particles of debris (dentine particles and pulp remnants) which are seen under a surgical microscope.
This layer is created when the instrument touches the dentine (friction force of the instrument applied to the wall of the canal). It takes the form of a thin amorphous structure composed of dentine particles, pulp remnants, bacteria and their metabolites, solutions used to rinse the canal and even parts of the material from which the tools are made. According to recent standards, the smear layer should be removed since it may, among others, hinder disinfection of the canal (infected root canals) and later cause leakage of the filling (3,4, 11‑15). Endostar E3 (Poldent) is one of the many rotary nickel‑titanium systems available on the Polish market. In contrast to conventional rotary file systems, the Endostar E3 Basic system (fig.1) is composed of three instruments which can be used in preparation of most root canals. These files have two cutting edges which provide effective dentine cutting power and an inactive, non‑cutting tip, which significantly limits the creation of ledges and perforations.Aim and objectives
The aim of the paper was to evaluate the cleanliness of the walls of root canals prepared with the use of the Endostar E3 Basic system.
Materials and methods
Research material and canal preparation In order to be able to compare the results with other observations (9,10), the same method was used as in the cited literature (among others the same rinsing solutions, lubricants, research material‑similar root canal morphology and cleanliness evaluation criteria).
The study used 8 disto‑buccal roots of the maxillary molars, which did not undergo endodontic treatment, had fully formed apexes and were not damaged (without cracks or resorption cavities). After access to the pulp chamber was created, the canal orifices were widened and working length was established. In order to perform this, a size 10 K‑file was inserted into the canal until the apex of the file became visible through the anatomical foramen. Working length was established by subtracting 1 mm from this length. Next, the initial apical file length was stablished, this way qualifying canals sized ISO 15 for this study (a #15 K‑file was inserted to the canals at working length until a tug‑back sensation was achieved).The Endostar E3 Basic instruments, which were mounted onto the Endostar ProEndo (Poldent) handpiece (fig. 2) were used to prepare the canal. The canal orifice and coronal portion of the canal were shaped with the use of instrument no. 1 (30/08; the instrument with one blue stripe). The in‑strument was inserted no more than to half of the root canal length. Next, hand K‑files were used to widen the apical part of the canal to size ISO 20, which was followed by widening the canal with the following‑size rotary file (instrument no 2. 25/06, two red stripes on the handle). This instrument was inserted to a maximum ⅔ of the root canal length and an up‑down motion was applied. Recapitulation with the size 15 K‑file was performed by inserting the tool at full working length. This was followed by shaping the apical portion of the canal, which was done with instrument no. 3 (30/04; the instrument with three blue stripes). Whenever the size of the file was upgraded, the canals were irrigated with 2 mL of 2.5% sodium hypochlorite solution, which was applied through a syringe and size 30 endodontic needle with a foramen at the apex (the needle was inserted 1.5 ‑ 2 mm shorter than maximum preparation length), File‑ Eze (Ultradent) was used as a lubricant. 5 L of distilled water was used for final irrigation and standardized paper points (Poldent) were used to dry the canal.
Observations in the SEM
After performing circular cuts r on the roots of the teeth (at the level of the cervix) with a flame‑shaped bur, the roots were broken off. This was followed by forming longitudinal
fissures on the the lingual and buccal surfaces with the same burr. Next, the roots were cut in half in order to make the lumen of the canal visible. Wire‑cutting pliers were used to crack the root apart. The better preserved of the two was qualified for further testing. The samples were dehydrated with ethanol, dried in the critical point and a layer of AuPd40 was sprayed on. The inner surfaces of the canals were analyzed in the scanning electron microscope JEOL 6100 (Jeol) and magnified 200 times, which showed pulp remnants and dentine debris. The smear layer was evaluated at 1000x magnification. Evaluation of randomly chosen microscopic fields was performed in the coronal, middle and apical thirds of the roots, separately for debris and the smear layer using the criteria first described by Hulsman et al. (16).
A 5‑category scale was used to perform debris evaluation:
Category 1 ‑ the wall of the root canal is clean, only a some debris is visible,
Category 2 ‑ single, small agglomerations of debris,
Category 3 ‑ numerous agglomerations of debris, however covering less than 50% of the surface of the wall the root canal,
Category 4 ‑ more than 50% of the wall of the root canal is covered by debris,
Category 5 ‑ the wall of the root canal is completely or almost completely covered with debris.
A 4‑category scale was also used to evaluate the semar leyer:
Category 1 ‑ no smear layer, open dentinal tubules,
Category 2 ‑ small amount of smear layer, part of the dentinal tubules remain open,
Category 3 ‑ the surface is covered with a homogenous smear layer, only singe dentinal tubules remain open,
Category 4 ‑ the wall of the root canal is completely covered with a homogenous smear layer, no open dentinal canals,
Category 5 ‑ copious, nonhomogenous smear layer completely covering the wall of the root canal.
Statistical analysis
Statistical analysis was performed with the Fisher’s exact test. Statistical significance was defined at p < 0.05.
Results
The results of the analysis carried out in 200x magnification were presented in Table 1 and in Figure 3. The walls of the root canals were usually clean ( category 1 ), although segments covered with debris were also observed ( category 2‑ 5). Statistical analysis did not show significant differences between individual segments in the canal.
The results of the analyses carried out in 100x magnification were presented in table 2 and figure 4. The smear layer which emerged as a result of cutting the dentine with the
Endostar E3 tools, was relatively copious and completely covered the roots surface (category 5). Categories 1 to 4 were more rarely assigned. As in the previous case, no statistical significance was seen between individual segments of the canal.
Discussion
The aim of the mechanical (biomechanical) preparation of the root canal is to model it to a certain size and shape that would allow efficient irrigation and later its proper filing throughout its entire length without pushing the material into the periapical area. Apart from proper shaping of the canal it is extremely important to remove the contents of the canal and debris generated during cleaning (3,4).
According to many publications, rotary file systems lets us prepare the canal without losing its natural shape and providing good cleaning of the canal (1, 9, 10, 17‑20). In comparison with the hand‑held instruments, they provide better cleaning in a significantly much shorter time, however do not guarantee an ideal effect.
| Table I. Evaluation of debris. | ||||
| Category | Coronal part | Middle part | Apical part | Sum |
|---|---|---|---|---|
| 1 | 6 | 5 | 5 | 16 |
| 2 | 0 | 1 | 0 | 1 |
| 3 | 1 | 1 | 2 | 4 |
| 4 | 1 | 1 | 1 | 3 |
| 5 | 0 | 0 | 0 | 0 |
The aim of our own study was to evaluate the cleanliness of the walls of the root canals prepared with the Endostar E3 system. In order to compare the obtained results with the previous observations, a methodology very similar to those in the cited papers was used (9, 10). Sodium hypochlorite was used for irrigation. A chelating solution was not used, only a gel consisting sodium versenate was applied. SEM observations were made under the same magnifications (200x and 1000x) and evaluated with the same scale (Hulsman scale).
| Table II. Evaluation of smear layer | ||||
| Category | Coronal part | Middle part | Apical part | Sum |
|---|---|---|---|---|
| 1 | 0 | 0 | 0 | 0 |
| 2 | 0 | 0 | 0 | 0 |
| 3 | 1 | 2 | 0 | 3 |
| 4 | 2 | 1 | 2 | 5 |
| 5 | 5 | 5 | 6 | 16 |
In our own study, the presence of a more or less homogenous smear layer was found during microscopic evaluation at large magnifications. Similar results were obtained in previous studies (9,10), although this was not the case in the ProFile system where the smear layer was smaller in the coronal part of the canal compared to the middle and apical parts. The differences between the amount of smear layer generated by the Endostar E3 and Mtwo file systems compared with the ProFile are probably the result of the selection of research material. The study which evaluated the efficacy of the ProFile instruments used single‑root premolars. In premolars, the coronal part of the root canal is naturally bigger than the remaining two parts. Therefore, there is a smaller chance of the instrument touching this part of the canal resulting in a reduced smear layer. Whereas, in the studies evaluating the cleanliness of the canals after applying the Mtwo and Endostar E3 system, teeth with a similar root‑canal system morphology were used (mesial roots of mandibular molars and disto‑buccal roots of the maxillary molars vs. distobuccal roots of maxillary molars). These canals are relatively narrow and only slightly become wider in the direction of the pulp chamber. We can therefore assume that during preparation, the instruments contact the walls on a relatively large area, thus generating a more abundant smearlayer.
Similarly to the previous studies, a chelating solution was not used for irrigation. It was assumed that the use of such solution would dissolve the smear layer and this way hinder instrument and smear layer valuation. The presence of the smear layer in a certain area means that the instrument was in contact with that area.
To summarize, the cleanliness of the canals prepared with the use of the Endostar E3 system is similar to that observed in the ProFile and Mmtwo systems (lack of debris and a relatively copious smear layer).
References
1. Schäfer E., Erler M., Dammaschke T.: Comparative study on the shaping ability and cleaning efficiency of rotary Mtwo instruments. Part 2. Cleaning effectiveness and shaping ability in severely curved root canals of extracted teeth. Int. Endod. J., 2006, 39, 3, 203‑212.
2. Hülsmann M., Schäfer E.: Probleme in der Endodontie. Prävention. Identyfication and Management. Quintessenz, Berlin 2017.
3. Jańczuk Z., Kaczmarek U., Lipski M.: Stomatologia zachowawcza z endodoncją. Zarys kliniczny. PZWL, Warszawa 2014.
4. Arabska‑Przedpełska B., Pawlicka H.: Współczesna endodoncja w praktyce. Bestom, Łódź 2011.
5. Wilkoński W. i wsp.: Analiza porównawcza jakości opracowania kanałów korzeniowych za pomocą systemów rotacyjnych ProTaper i Mtwo oraz systemu recyprokalnego Reciproc – badanie in vitro. Porad. Stomatol., 2011, 115, 9, 340‑347.
6. Wilkoński W. i wsp.: Porównanie skuteczności opracowania kanałów korzeniowych instrumentami Reciproc 25 oraz ProTaper F2 z zastosowaniem techniki Ghassana Yareda – badanie in vitro. Mag. Stomatol., 2011, 21, 11, 144‑150, online.
7. Wilkoński W. i wsp.: Porównanie jakości opracowania kanałów korzeniowych techniką rotacyjną narzędziami Mtwo oraz techniką recyprokalną narzędziami Reciproc 25, ProTaper F2 oraz WaveOne Primary – badanie in vitro. Porad. Stomatol., 2011, 118, 11, 480‑487.
8. Wilkoński W. i wsp.: Analiza porównawcza jakości opracowania kanałów korzeniowych systemami narzędzi rotacyjnych K3 oraz HyFlex. Badanie in vitro. Mag. Stomatol., 2014, 24, 1, 126‑131, online.
9. Lichota D., Lipski M., Woźniak K.: Ocena czystości ścian kanałów korzeniowych opracowanych za pomocą narzędzi ProFile: badania w SEM. Czas. Stomatol., 2005, 58, 3, 151‑157.
10. Lichota D. i wsp.: Czystość ścian kanałów korzeniowych po opracowaniu rotacyjnymi narzędziami niklowo‑tytanowymi Mtwo: badanie w SEM. Ann. Acad. Med. Stetin., 2008,
54, 3, 58‑62.
11. Torabinejad M. i wsp.: Clinical implications of the smear layer in endodontics: a review. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod., 2002, 94, 6, 658‑666.
12. George S., Kishen A., Song K.P.: The role of environmental changes on monospecies biofilm formation on root canal wall by Enterococcus faecalis. J. Endod., 2005, 31, 12,
867‑872.
13. Yang S.E., Bae K.S.: Scanning electron microscopy study of the adhesion of Prevotella nigrescens to the dentin of prepared root canals. J. Endod., 2002, 28, 6, 433‑437.
14. Kokkas A.B. i wsp.: The influence of the smear layer on dentinal tubule penetration depth by three different root canal sealers: an in vitro study. J. Endod., 2004, 30, 2, 100‑102.
15. Saleh I.M. i wsp.: Bacterial penetration along different root canal filling materials in the presence or absence of smear layer. Int. Endod. J., 2008, 41, 1, 32‑40.
16. Hülsmann M., Rümmelin C., Schäfers F.: Root canal cleanliness after preparation with different endodontic handpieces and hand instruments: a comparative SEM investigation. J. Endod., 1997, 23, 5, 301‑306.
17. Zand V. i wsp.: A comparative SEM investigation of the smear layer following preparation of root canals using nickel titanium rotary and hand instruments. J. Oral Sci., 2007,
49, 1, 47‑52.
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