Hand Instrumentation Techniques Research Articles

Calcium hydroxide fillings in curved canals: influence of apical enlargement using the rotary systems ProTaper, K3, and two hand instrumentation techniques

Objective: This study aimed to analyze the influence of the instrumentation technique (hand or rotary), and apical enlargement on calcium hydroxide (CH) fillings in curved canals. Materials and method: One hundred and ten simulated root canals were divided into eleven experimental groups (G). Canals were prepared with K-Flexofile hand instruments, using either crown-down (GCD 25, GCD 30 and GCD 35) or step-back (GSB 25, GSB 30 and GSB 35) techniques; and with rotary instruments, using either ProTaper (GPT F1 and GPT F2) or K3 (GK3 25, GK3 30 and GK3 35) systems. The apical diameter correspon- ded to 0.20 mm (GPT F1), 0.25 mm (GCD 25, GSB 25, GPT F2 and GK3 25), 0.30 mm (GCD 30, GSB 30, GK3 30), and 0.35 mm (GCD 35, GSB 35, GK3 35). A CH paste, previously colored with blue Indian ink, was injected into the canals using a special syringe. The four sides of the blocks with simulated canals were scanned and the images were transferred to the AutoCAD-2008 software, for assessing the amount (%) of filling in the apical 5 mm (ANOVA; Tukey’s Test; α=0.05). Qualitative analysis was also performed regarding the presence or absence of voids (Chisquare Test; α=0.05). Results: In GSB, there was significant difference between diameters 25 and 30. GSB showed lower amount of filling (P<0.05) than GK3, when the apical diameter corresponded to 0.30 mm. GCD showed lower amount of filling (P<0.05) than the other groups (SB, PT, and K3), when the apical diameter corresponded to 0.25 mm. No significant difference was detected when comparing the four sides of the blocks. Conclusion: Preparation technique and apical diameter had slight or no relevant influence on CH paste filling in simulated curved root canals. Statistical differences found in this study may be clinically irrelevant, since the amount of filling, regardless of preparation technique and apical diameter, was very close or equal to 100%. Keywords: Endodontics. Root canal preparation. Calcium hydroxide.

Comparative evaluation of debris extruded apically by using, Protaper retreatment file, K3 file and H-file with solvent in endodontic retreatment

Aim: The aim of this study was to evaluate the apical extrusion of debris comparing 2 engine driven systems and hand instrumentation technique during root canal retreatment. Materials and Methods: Forty five human permanent mandibular premolars were prepared using the step-back technique, obturated with gutta-percha/zinc oxide eugenol sealer and cold lateral condensation technique. The teeth were divided into three groups: Group A: Protaper retreatment file, Group B: K3, file Group C: H-file with tetrachloroethylene. All the canals were irrigated with 20ml distilled water during instrumentation. Debris extruded along with the irrigating solution during retreatment procedure was carefully collected in preweighed Eppendorf tubes. The tubes were stored in an incubator for 5 days, placed in a desiccator and then re-weighed. Weight of dry debris was calculated by subtracting the weight of the tube before instrumentation and from the weight of the tube after instrumentation. Data was analyzed using Two Way ANOVA and Post Hoc test. Results : There was statistically significant difference in the apical extrusion of debris between hand instrumentation and protaper retreatment file and K3 file. The amount of extruded debris caused by protaper retreatment file and K3 file instrumentation technique was not statistically significant. All the three instrumentation techniques produced apically extruded debris and irrigant. Conclusion: The best way to minimize the extrusion of debris is by adapting crown down technique therefore the use of rotary technique (Protaper retreatment file, K3 file) is recommended.

Comparative evaluation of apical extrusion of bacteria using hand and rotary systems : An in vitro study

Aim:To evaluate the bacteria extruded apically during root canal preparation using two hand and rotary instrumentation techniques.Materials and Methods:Eighty freshly extracted mandibular premolars were mounted in bacteria collection apparatus. Root canals were contaminated with the pure culture of Enterococcus fecalis (ATCC 29212) and dried at 37°C for 24 h. Bacteria extruded were collected, incubated in brain heart infusion agar for 24 h at 36°C and the colony forming units (CFU) were counted.Statistical Analysis:The mean number of colony forming units were calculated by One-way ANOVA and comparison between the groups made by multiple comparison (Dunnet D) test.Results:The step-back technique extruded highest number of bacteria in comparison to other hand and rotary Ni–Ti systems.Conclusion:Under the limitation of this study all hand and rotary instrumentation techniques extruded bacteria. Among all the instrumentation techniques step-back technique extruded more number of bacteria and K-3 system the least. Further in vivo research in this direction could provide more insight into the biologic factors associated and focus on bacterial species that essentially play a major role in post instrumentation flare-ups.

The effect of a manual instrumentation technique on five types of premolar root canal geometry assessed by microcomputed tomography and three-dimensional reconstruction

BackgroundTogether with diagnosis and treatment planning, a good knowledge of the root canal system and its frequent variations is a necessity for successful root canal therapy. The selection of instrumentation techniques for variants in internal anatomy of teeth has significant effects on the shaping ability and cleaning effectiveness. The aim of this study was to reveal the differences made by including variations in the internal anatomy of premolars into the study protocol for investigation of a single instrumentation technique (hand ProTaper instruments) assessed by microcomputed tomography and three-dimensional reconstruction.MethodsFive single-root premolars, whose root canal systems were classified into one of five types, were scanned with micro-CT before and after preparation with a hand ProTaper instrument. Instrumentation characteristics were measured quantitatively in 3-D using a customized application framework based on MeVisLab. Numeric values were obtained for canal surface area, volume, volume changes, percentage of untouched surface, dentin wall thickness, and the thickness of dentin removed. Preparation errors were also evaluated using a color-coded reconstruction.ResultsCanal volumes and surface areas were increased after instrumentation. Prepared canals of all five types were straightened, with transportation toward the inner aspects of S-shaped or multiple curves. However, a ledge was formed at the apical third curve of the type II canal system and a wide range in the percentage of unchanged canal surfaces (27.4-83.0%) was recorded. The dentin walls were more than 0.3 mm thick except in a 1 mm zone from the apical surface and the hazardous area of the type II canal system after preparation with an F3 instrument.ConclusionsThe 3-D color-coded images showed different morphological changes in the five types of root canal systems shaped with the same hand instrumentation technique. Premolars are among the most complex teeth for root canal treatment and instrumentation techniques for the root canal systems of premolars should be selected individually depending on the 3-D canal configuration of each tooth. Further study is needed to demonstrate the differences made by including variations in the internal anatomy of teeth into the study protocol of clinical RCT for identifying the best preparation technique.

The Effect of Three Different Rotary Instrumentation Systems on Substance P and Calcitonin Gene-related Peptide Expression in Human Periodontal Ligament

Introduction The purpose of this study was to quantify the effect of three different rotary root canal preparation systems on substance P and calcitonin gene-related peptide expression in healthy human periodontal ligament. Methods Fifty periodontal ligament samples were obtained from healthy premolars in which extraction was indicated for orthodontic reasons. Before extraction, 40 of these premolars were equally divided into four groups, and root canals were prepared using four different systems: the ProTaper Universal rotary system, the RaCe rotary system, the Mtwo rotary system, and the hand instrumentation technique. The remaining 10 healthy premolars that were extracted without treatment served as a negative control group. All periodontal ligament samples were processed, and SP and CGRP were measured by radioimmunoassay. Results Greater SP and CGRP expression were found in the ProTaper Universal group followed by the hand instrumentation group, the RaCe, and the Mtwo groups. The lower SP and CGRP values were for the negative control group. The Kruskal-Wallis test showed statistically significant differences between groups ( p < 0.0001). Post hoc Least Significant Difference (LSD) tests showed statistically significant differences in SP and CGRP expression between the negative control group and all the other groups except the Mtwo group. Hand instrumentation also showed statistically significant differences with all the other groups, except the ProTaper Universal group. Differences between the three rotary systems were also statistically significant. Conclusion SP and CGRP expression in periodontal ligament increases when teeth are prepared with ProTaper Universal and RaCe rotary instrumentation systems as well as with hand instrumentation. Mtwo maintains SP and CGRP levels.

A comparison of three rotary systems and hand instrumentation technique for the elimination of Enterococcus faecalis from the root canal

The aim of this study was to compare the in vitro reduction of a bacterial population in a root canal by mechanical instrumentation using three rotary systems and hand instrumentation technique. The root canals contaminated with a suspension of Enterococcus faecalis were instrumented using ProTaper, K3, HeroShaper and K-file hand instrumentation technique. Later the root canals were sampled. After serial dilutions, samples were incubated in culture media for 24 h. Bacterial colonies were counted and the results were given as number of colony-forming units per millilitre. The results showed that all the canal instrumentation systems reduced the number of bacterial cells in the root canals. Statistically, ProTaper instruments were more effective in reducing the number of bacteria than the other rotary files or hand instruments.

Efficacy of various concentrations of NaOCl and instrumentation techniques in reducing Enterococcus faecalis within root canals and dentinal tubules

To evaluate the efficacy of 0.5%, 2.5% and 5.25% sodium hypochlorite (NaOCl) as intracanal irrigants associated with hand and rotary instrumentation techniques against Enterococcus faecalis within root canals and dentinal tubules. A total of 180 extracted human premolar teeth were infected for 21 days with E. faecalis. The specimens were divided into 12 groups, as follows: group 1: 5.25% NaOCl + Hybrid technique (Valdrighi et al. 1998); group 2: 5.25% NaOCl + nickel-titanium (NiTi) rotary technique 4 mm shorter than the apex (by FOP-UNICAMP); group 3: 5, 25% NaOCl + NiTi rotary technique (Hero 642); group 4: 2.5% NaOCl +Hybrid technique; group 5: 2.5% NaOCl + NiTi rotary technique 4 mm shorter than the apex; group 6: 2.5% NaOCl + NiTi rotary technique (Hero 642); group 7: 0.5% NaOCl + Hybrid technique; group 8: 0.5% NaOCl + NiTi rotary technique 4 mm shorter than the apex; group 9: 0.5% NaOCl + NiTi rotary technique (Hero 642); group 10: sterile saline solution + Hybrid technique; group 11: sterile saline solution + NiTi rotary technique 4 mm shorter than the apex; group 12: sterile saline solution + NiTi rotary technique (Hero 642). Canals were sampled before and after preparation. After serial dilution, samples were plated onto brain heart infusion (BHI) agar, and the colony forming units (CFU) that were grown were counted. The teeth were sectioned into three thirds and dentine chips were removed from the canals with conical burs. The samples obtained with each bur were immediately collected into test tubes containing BHI broth, and were incubated at 37 degrees C and plated onto BHI agar. The CFU were counted and analysed. At all depths and thirds of the root canals and for all techniques used, 5.25% NaOCl was shown to be the most effective irrigant solution tested when dentinal tubules were analysed, followed by 2.5% NaOCl. No differences among concentrations in cleaning the canals were found. Especially at higher concentrations, NaOCl, was able to disinfect the dentinal tubules, independent of the canal preparation technique used.

The Quality of Apical Canal Preparation Using Hand and Rotary Instruments with Specific Criteria for Enlargement Based on Initial Apical File Size

The aim of this study was to compare the quality of apical enlargement of mesiobuccal canals of mandibular molars using conventional stainless steel hand files (K files) and nickel-titanium (Ni-Ti) rotary instruments (LightSpeed). Thirty freshly extracted mandibular molars were randomly assigned to three equal groups (n = 10 each group). The mesiobuccal canals were instrumented with K file using step-back technique without coronal flaring (control; group 1), K file using step-back technique after coronal flaring (group 2), and LightSpeed instrumentation (group 3). Specific criteria for apical enlargement based on initial apical size were used. For step-back techniques, the master apical file sizes were based on the Grossman criterion of three sizes larger than the first file that bound at working length, without coronal flaring (group 1) and with flaring (group 2). For the LightSpeed (LS) group, the master apical rotary sizes were based on the manufacturer's recommendation. Canal cleanliness, canal transportation, and final canal shapes were determined histologically at 1-mm and 3-mm levels short of the working length. Canals were prepared to significantly larger sizes using LS instrumentation than with either hand instrumentation techniques (15-17 ISO units, p < 0.001). LS instrumentation allowed greater apical enlargement with significantly cleaner canals, less apical transportation, and better canal shape than both hand instrumentation groups at both levels (p < 0.05). None of the three techniques was totally effective in cleaning the apical canal space. It was concluded that greater apical enlargement using LS rotary instruments is beneficial as an attempt to further debride the apical third region in mesiobuccal canals of mandibular molars. Instrument designs, alloy properties, and canal curvature are important factors that determine the feasibility of greater apical enlargement in narrow canals.

Effect of preflaring on canal transportation: Evaluation of ultrasonio, sonic, and conventional techniques

This study evaluated the effect on canal transportation when acrylic canals were preflared with Peeso reamers before the use of ultrasonic, sonic, and hand instrumentation techniques. Twenty resin blocks with simulated curved root canals were shaped with each technique to a size 40 file 0.5 mm from the apical foramen. Ten of the canals were preflared in the cervical region with No. 1 and No. 2 Peeso reamers before instrumentation; 10 canals that were not preflared served as controls. Transportation was measured on the inside canal curvature 3 mm from the canal orifice and 8 mm cervical to the working length, and on the outside canal curvature 1 mm cervical to the working length. Statistical analysis with Student'sttest did not show a significant reduction in canal transportation for the preflared groups. In some areas the amount of transportation was less for the preflared groups; in other areas it was greater.

An Evaluation of the Rotational Hand Instrumentation Technique in Curved Root Canals

An Evaluation of the Rotational Hand Instrumentation Technique in Curved Root Canals

The effect of varying the ultrasonic power setting on canal preparation

The purpose of this study was to evaluate the effect of instrumenting root canals using an ultrasonic device (Enac) at different power levels on the prepared canal shape and instrumentation time, and to compare these results with those obtained using a standardized hand instrumentation technique. The mesial canals (120) of 60 human mandibular first and second molars were randomly assigned to one of six groups. In groups A through D, the canals were instrumented using the Enac ultrasonic unit at different power settings (1, 2, 3, and 5, respectively). Group E was hand instrumented. Group F served as uninstrumented controls. The roots were then sectioned horizontally and the canal shapes examined, as was the mesiodistal canal diameter as it relates to the external root surface. Instrumentation time for each group was recorded. Ultrasonic instrumentation at the different power settings was significantly faster than hand instrumentation (p less than 0.001). However, the difference between the different power levels was not significant. There were no significant differences between the different groups as to the effect on the prepared canal shape. The only problem arising from using the Enac at a power level more than the recommended (5) was the greater tendency to break size #15 files during instrumentation. Using the Enac at power level 3 provided satisfactory instrumentation capability with minimal risk of file breakage.

Comparison of mechanical and standard hand instrumentation techniques in curved root canals

The original and postinstrumentation shapes of the mesial root canal system of 12 mandibular molars were compared after being instrumented with a mechanical handpiece and a hand instrumentation technique. Area of dentin removed and amount and direction of transportation were evaluated in relation to degree of root canal curvature. Pre- and postinstrumentation measurements were taken of the root canal system in the cervical, middle, and apical thirds. The mechanical handpiece removed dentin and transported the root canal more than the hand instrumentation in the cervical and apical thirds. Both techniques transported to the distal in the cervical third and to the mesial in the apical third. In the middle third, the mechanical handpiece transported more to the mesial and the hand instrumentation more to the distal. Degree of root canal curvature had no influence on the amount of dentin removed or transportation of the root canal.

Effect of sonic versus ultrasonic instrumentation on canal preparation

The instrumentation time, and the resulting root canal angulation change and shape after using ultrasonic, sonic, and hand instrumentation techniques were studied in the mesial canals of 55 extracted human mandibular first and second molars. After instrumentation, the roots were sectioned horizontally in the apical, middle, and coronal thirds and evaluated for shape, mesial and distal canal widths, and canal diameter. MM3000 and hand were significantly faster than the other techniques (p less than 0.005). MM3000 resulted in less angulation change than the Enac (p less than 0.005). Hand instrumentation was judged to have given the best shape (p less than 0.01).

An in vitro histological comparison of the step-back, sonic, and ultrasonic instrumentation techniques in small, curved root canals

The effectiveness of different methods of root canal instrumentation in small, curved canals was assessed by histological examination. Compared were the step-back hand instrumentation technique, sonic instrumentation with the Endostar 5, and ultrasonic instrumentation with the Cavi-Endo and PZ-KTec prototype systems. Eighty root canals in freshly extracted humanteeth were randomly placed into these four instrumentation groups of 20 teeth each. Five uninstrumented canals served as controls. Following canal preparation and histological processing, coronal, middle, and apical cross-sections were examined for areas of remaining debris and predentin, the percentage of planed canal walls, and percentage of increase in canal area. The results showed significant differences among the four canal preparation methods in all evaluation categories.

The effect of endosonic instrumentation in simulated curved root canals

This study evaluated the effects of ultrasonic, sonic, and conventional instrumentation techniques on curved root canals. Fifty resin blocks with curved canals were divided into five groups. Each group was instrumented by one of the following techniques: conventional hand instrumentation, sonic instrumentation using the Medidenta MM3000 unit, sonic instrumentation using the Syntex Endostar 5 unit, ultrasonic instrumentation using the Caulk Cavi-Endo unit, and ultrasonic instrumentation using the Osada Enac OE-2 unit. All preparations were made to the size of a#35 K-type file. Measurements of the amount of transportation of the canal were made at the apical and middle portions of the preparations. The results were significantly different based on statistical analysis of variance. A multiple comparison test revealed that the Medidenta and Caulk systems transported significantly less at the apex of the curved canals than the Syntex system and hand instrumentation techniques. The Medidenta, Syntex, and hand instrumentation transported significantly less in the middle portion of the curved canals than the Caulk and Osada systems. This study evaluated the effects of ultrasonic, sonic, and conventional instrumentation techniques on curved root canals. Fifty resin blocks with curved canals were divided into five groups. Each group was instrumented by one of the following techniques: conventional hand instrumentation, sonic instrumentation using the Medidenta MM3000 unit, sonic instrumentation using the Syntex Endostar 5 unit, ultrasonic instrumentation using the Caulk Cavi-Endo unit, and ultrasonic instrumentation using the Osada Enac OE-2 unit. All preparations were made to the size of a#35 K-type file. Measurements of the amount of transportation of the canal were made at the apical and middle portions of the preparations. The results were significantly different based on statistical analysis of variance. A multiple comparison test revealed that the Medidenta and Caulk systems transported significantly less at the apex of the curved canals than the Syntex system and hand instrumentation techniques. The Medidenta, Syntex, and hand instrumentation transported significantly less in the middle portion of the curved canals than the Caulk and Osada systems.

Hand versus ultrasonic instrumentation: Its effect on canal shape and instrumentation time

The resulting root canal shape after using ultrasonic and hand instrumentation techniques as well as the instrumentation time was studied in 63 extracted human mandibular first and second molars. The mesial canals were instrumented alternating the techniques between the buccal and lingual canals. After instrumentation, the roots were sectioned horizontally, in the, apical, middle, and coronal thirds and evaluated for shape and location. The mean hand instrumentation time, 8 min, was significantly less than the mean ultrasonic instrumentation time, 11 min (p<0.001). Hand instrumentation was judged to have given the best shape in 59% of the canals at the apical, 68% at the middle, and 65% at the coronal levels. Both techniques seemed to cause the canal to move toward the furcation about equally in the middle and coronal thirds of the root. The resulting root canal shape after using ultrasonic and hand instrumentation techniques as well as the instrumentation time was studied in 63 extracted human mandibular first and second molars. The mesial canals were instrumented alternating the techniques between the buccal and lingual canals. After instrumentation, the roots were sectioned horizontally, in the, apical, middle, and coronal thirds and evaluated for shape and location. The mean hand instrumentation time, 8 min, was significantly less than the mean ultrasonic instrumentation time, 11 min (p<0.001). Hand instrumentation was judged to have given the best shape in 59% of the canals at the apical, 68% at the middle, and 65% at the coronal levels. Both techniques seemed to cause the canal to move toward the furcation about equally in the middle and coronal thirds of the root.