• Restorative Dentistry and Endodontics
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• v.48 no.1
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• pp.1.1-1.11
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• 2023

Objectives: This study evaluated the dentinal penetration depth of 2.5% sodium hypochlorite (NaOCl) in root canals with and without preparation and different irrigant activation protocols. Materials and Methods: Sixty-three bovine mandibular incisors were randomly allocated to 6 groups (n = 10): G1, preparation + conventional needle irrigation (CNI); G2, preparation + passive ultrasonic irrigation (PUI); G3, preparation + Odous Clean (OC); G4, no preparation + CNI; G5, no preparation + PUI; G6, no preparation + OC; and CG (negative control; n = 3). Samples were filled with crystal violet for 72 hours. Irrigant activation was performed. Samples were sectioned perpendicularly along the long axis, 3 mm and 7 mm from the apex. Images of the root thirds of each block were captured with a stereomicroscope and analyzed with an image analysis software. One-way analysis of variance, followed by the Tukey post hoc test, and the Student's t-test were used for data analysis, with a significance level of 5%. Results: The NaOCl penetration depth was similar when preparation was performed, regardless of the method of irrigation activation (p > 0.05). In the groups without preparation, G6 showed greater NaOCl penetration depth (p < 0.05). The groups without preparation had a greater NaOCl penetration depth than those with preparation (p = 0.0019). Conclusions: The NaOCl penetration depth was similar in groups with root canal preparation. Without root canal preparation, OC allowed deeper NaOCl penetration. The groups without preparation had greater NaOCl penetration than those undergoing root canal preparation.

• The Journal of the Korean dental association
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• v.45 no.6 s.457
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• pp.362-369
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• 2007

The aim of this study was to investigate the effect of the hybrid instrumentation method with ProTaper and ProFile on the change of root canal area and distance from the canal to the root surface after canal shaping. The mesial canals of twenty extracted mandibular first molars having $10-20^{\circ}\Delta$ curvature were scanned using X-ray microcomputed tomography (XMCT)-scanner before root canals were instrumented. They were divided into four groups (n=10 canals ter group). In Group 1, root canals were instrumented by the step-back technique with stainless steel K-Flexofile after coronal flaring. The remainders were instrumented by the crown-down technique with, ProTaper system (Group 2), ProFile (Group 3) or ProTaper (Group 4). All canals were prepared up to size 25 at the end-point of preparation and scanned again. Pre- and post-operative cross-sectional images of 1, 3, 5, and 7 mm from the apical foramen were compared. For each level, change of cross-sectional canal are and distance to the nearest external root surface was calculated using Adobe Photoshop 6.0 and image software program. In the change of cross-sectional area, Group 4 was less than Group 2 at 3 mm and 5 mm level (p<0.05). In the difference of the distance from the canal to the root surface after canal shaping, Group 4 was least among the other groups at 7 mm level (p<0.05). According to the results, the methods using ProFile or K file only and the hybrid instrumentation technique using ProTaper and ProFile are more appropriate methods of canal preparation than ProTaper system for narrow of curved canals.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.477-486
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• 1998

Recently the development of rotary instrument makes it possible that in root canal treatment operator saves much more time, maintans original curved canal shape and easily prepares continuous tapered root canal. The purpose of this experiment was to examine the smoothness of the internal surface of prepared root canal and the effectiveness of debridement in prepared root canal by SEM for the comparison of hand and Ni-Ti rotary instrument. 25 extracted human teeth were access opened and # 10 K-type file was introduced into canal until it was appeared at the apical foramen. The working length was established by subtracting 0.5mm from this measurement. Group 1. The root canal preparation was done to # 30 with working length and then step-back until # 45 with K-Flexofile (Maillefer, Swiss). Group 2. Root canal preparation was done by Naviflex Ni-Ti file (Brasseler, USA) as the same technique with group 1. Group 3. Canal was prepared by Profile .04 (Maillefer, Swiss) taper until #30. Group 4. With use of Quantec (Tycom, USA) root canal was prepared from file number 1 to 8. In group 1 and 2, the root canal irrigant was NaOCl and the other groups, NaOCl and RC-prep (Premine Dental Products, USA) was used. The prepared teeth were notched with high-speed bur as bucco-lingual direction and fractured with chisel and mallet, then examined with SEM. Group 1 showed smooth internal surface. There were scratches mainly to the axial direction. Group 2 showed similar characteristics to those in group 1. Group 3 showed more smoother and linear cutting surface with bised scratches. Group 4 has the almost same characteristics group 3 and there was no difference in the file design. Ni-Ti rotary root canal instrument prepare the dentinal wall more smoother than hand instrument. The effectiveness of debridement was not fully affected by file design. The isthmus area and accessory canals of the root canal system were not prepared in any group. According to the result, hand and rotary type instrumentation techniques were effective in removal of major amount of tissue from root canal but it was not complete. In the direction of cutting movement there was difference between them.

• Restorative Dentistry and Endodontics
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• v.45 no.2
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• pp.21.1-21.12
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• 2020

The aim of this article was to review age-dependent clinical recommendations for appropriate root canal instrumentation techniques. A comprehensive narrative review of canal morphology, the structural characteristics of dentin, and endodontic outcomes at different ages was undertaken instead of a systematic review. An electronic literature search was carried out, including the Medline (Ovid), PubMed, and Web of Science databases. The searches used controlled vocabulary and free-text terms, as follows: 'age-related root canal treatment,' 'age-related instrumentation,' 'age-related chemo-mechanical preparation,' 'age-related endodontic clinical recommendations,' 'root canal instrumentation at different ages,' 'geriatric root canal treatment,' and 'pediatric root canal treatment.' Due to the lack of literature with practical age-based clinical recommendations for an appropriate root canal instrumentation technique, a narrative review was conducted to suggest a clinical algorithm for choosing the most appropriate instrumentation technique during root canal treatment. Based on the evidence found through the narrative review, an age-related clinical algorithm for choosing appropriate instrumentation during root canal treatment was proposed. Age affects the morphology of the root canal system and the structural characteristics of dentin. The clinician's awareness of root canal morphology and dentin characteristics can influence the choice of instruments for root canal treatment.

• The Journal of the Korean dental association
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• v.55 no.10
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• pp.688-694
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• 2017

Objectives: This preliminary study compared the effects of glide path establishing instruments prior to substantial root canal preparation. Materials and Methods: Glide path was established by enlargement of the 2nd mesiobuccal root canal of Dentalike by using three kinds of glide path preparation nickel-titanium file; PathFile, One G and ProGlider. The pre- and post-instrumented Dentalikes were weighed in the resolution of 1 / 10mg. In addition, after glide path preparation, torque generated during shaping using the WavoOne file was measured. The data were analyzed by one-way ANOVA and Tukey post-hoc test at a significance level of 95%. Results: The ProGlider had the significantly larger amount of reduced weight than other instrument groups (p < 0.05). There was no significant difference between group of glide path preparation with ProGlider and without glide path preparation in maximum torque and total stress generation during the shaping with WaveOne. Conclusions: Glide path preparation instruments may have different efficiency according to their geometries. The Dentalike artificial teeth were revealed to have discrepancies in the size of root canals by microCT examination. It is impossible to make a meaningful judgment of the results due to the reliability or resolution problem of the root canal size of the artificial tooth selected as the standardized tooth.

• Restorative Dentistry and Endodontics
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• v.13 no.1
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• pp.181-184
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• 1988

The purpose of this study was to evaluate the efficacy and safety of ultrasonic root canal preparation technique. 55 patients treated by each of the two techniques - ultrasonic and, hand - were evaluated the complications of two root canal preparation techniques. The results were as follows: 1. There was no difference in the pain incidence between the two groups. 2. There was no formation of performation and ledge in the ultrasonic group. 3. There was no difference in the shortening of working length between the two groups.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.220-227
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• 1997

The purpose of our study is to evaluate the ability of nickel-titanium(NiTi) files in maintaining the original curvature of a curved root canal during canal preparation. Curved canals on translucent resin blocks were prepared with NiTi and stainless steel files, and they were placed at the platform which can reproduce the same position. The unprepared and prepared canal forms were accurately compared by double exposure technique of photography. By finite element methods we also analyzed stress distributions of NiTi and stainless steel files in a curved canal. The results were as follows : 1. NiTi files were excellent in maintaining the original curvature of a curved canal than stainless steel files after canal preparation. 2. The results of canal preparation with these files were well verified by the analysis of stress distributions using finite element methods.

• Restorative Dentistry and Endodontics
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• v.29 no.4
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• pp.378-385
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• 2004

The purpose of this study was to compare the effects of preparation with GT files and profiles .04 in shaping of root canals and reconstruct the three-dimensional root canal system using micro computed tomography 40 canals of the extracted human mandibular molars were used, and randomly distributed into two experimental groups. In group 1. canals were prepared by GT files. In group 2, Profiles .04. were used. Apical preparation size was #30. For each tooth pre and post operative cross-sectional images were obtained by the micro CT at 50 micron intervals. Pre and post operative cross-sectional images of 1, 2, 3, 5, and 8mm from the apex were compared. For each section. canal area and centering ratio were determined. For each tooth pre- and post-operative root canal volume from the furcation to the apex of the roots was calculated by three-dimensional image software. Following results were obtained: 1. At 8mm from the apex, area of dentin removed by GT rotary file was significantly larger than that by Profile .04. And at the other levels there was not a significant difference. 2. There was a trend for GT rotary file to remain more centered in the canals than Profile .04 at all levels. But at 3mm level. there was a statistically significant difference. 3. In root canal volume increments after instrumentation, there was no significant difference between two groups.

• Restorative Dentistry and Endodontics
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• v.46 no.2
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• pp.16.1-16.11
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• 2021

Objectives: The aim of this study was to evaluate the shaping ability of the TruShape and Reciproc Blue systems and the apical extrusion of debris after root canal instrumentation. The ProTaper Universal system was used as a reference for comparison. Materials and Methods: Thirty-three mandibular premolars with a single canal were scanned using micro-computed tomography and were matched into 3 groups (n = 11) according to the instrumentation system: TruShape, Reciproc Blue and ProTaper Universal. The teeth were accessed and mounted in an apparatus with agarose gel, which simulated apical resistance provided by the periapical tissue and enabled the collection of apically extruded debris. During root canal preparation, 2.5% sodium hypochlorite was used as an irrigant. The samples were scanned again after instrumentation. The percentage of unprepared area, removed dentin, and volume of apically extruded debris were analyzed. The data were analyzed using 1-way analysis of variance and the Tukey test for multiple comparisons at a 5% significance level. Results: No significant differences in the percentage of unprepared area were observed among the systems (p > 0.05). ProTaper Universal presented a higher percentage of dentin removal than the TruShape and Reciproc Blue systems (p < 0.05). The systems produced similar volumes of apically extruded debris (p > 0.05). Conclusions: All systems caused apically extruded debris, without any significant differences among them. TruShape, Reciproc Blue, and ProTaper Universal presented similar percentages of unprepared area after root canal instrumentation; however, ProTaper Universal was associated with higher dentin removal than the other systems.

• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.38.1-38.10
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• 2020

Objectives: This study aimed to evaluate vital pulp tissue removal from different endodontic instrumentation systems from root canal apical third in vivo. Materials and Methods: Thirty mandibular molars were selected and randomly divided into 2 test groups and one control group. Inclusion criteria were a positive response to cold sensibility test, curvature angle between 10 and 20 degrees, and curvature radius lower than 10 mm. Root canals prepared with Hero 642 system (size 45/0.02) (n = 10) and Reciproc R40 (size 40/0.06) (n = 10) and control (n = 10) without instrumentation. Canals were irrigated only with saline solution during root canal preparation. The apical third was evaluated considering the touched/untouched perimeter and area to evaluate the efficacy of root canal wall debridement. Statistical analysis used t-test for comparisons. Results: Untouched root canal at cross-section perimeter, the Hero 642 system showed 41.44% ± 5.62% and Reciproc R40 58.67% ± 12.39% without contact with instruments. Regarding the untouched area, Hero 642 system showed 22.78% ± 6.42% and Reciproc R40 34.35% ± 8.52%. Neither instrument achieved complete cross-sectional root canal debridement. Hero 642 system rotary taper 0.02 instruments achieved significant greater wall contact perimeter and area compared to reciprocate the Reciproc R40 taper 0.06 instrument. Conclusions: Hero 642 achieved higher wall contact perimeter and area but, regardless of instrument size and taper, vital pulp during in vivo instrumentation is not entirely removed.