Relative efficacy of three Ni-Ti file systems used by undergraduates

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Currently, various Nickel-Titanium rotary files are used in endodontic treatment, but there is no one perfect system that can be applied to any clinical situation. Therefore, the combined uses of various file systems which can emphasize the advantages of each system are introduced as hybrid instrumentation.The ProTaper system is efficient in body shaping and apical pre-enlargement but is reported to have more possibility of transportation and produce more aberrations and deformation in more or less severe curved canals. Recently, new ProTaper system (ProTaper Universal) with different configuration and cross-sectional design to overcome the week points of ProTaper have been marketed.The purpose of this study was to compare and evaluate the shaping abilities of ProTaper, ProTaper Universal system, and two hybrid methods using S-series of ProTaper Universal and Hero Shaper or ProFile.The time lapses for instrumentation were measured and the used files were inspected for distortion. The pre-and post-instrumented root canals were scanned and superimposed to evaluate the aberrations and reduction of root canal curvature and change of radius of canal curvature. The increased canal width and apical centering ratio were calculated at 1, 2, 3, 4 and 5 ㎜ levels from apical foramen.Under the conditions of this study, the ProTaper Universal seems to have better shaping ability than ProTaper in terms of instrumented width and instrumentation time. It may be suggested that the ProTaper Universal system is efficient as much as hybrid instrumentation using ProTaper and other constant-tapered NiTi file systems in highly experienced operators. . And the use of NiTi rotary instrumentation can effectively produce a well-tapered root canal form sufficient for obturation with minimal risk of transporting the original canal, and are helpful in the preparation of curved root canals [2][3][4][5][6] . It is estimated that there are more than least 18 different rotary file brands in the endodontic marketplace 7) . Most of these NiTi file systemse.g. ProFile (Dentsply Maillefer, Ballaigues, Switzerland), K3 (SybronEndo, Glendora, France), Mtwo (VDW, Munich, Germany), Hero642 (Micromega, Besancon, France) and Hero Shaper (Micromega, Besancon, France), -have a constant tapered shaft design, while these have their own rake angles and radial lands 6,[8][9][10] . Distinctively, the ProTaper system (Dentsply Maillefer, Ballaigues, Switzerland) is an unique instrument which has progressively changing tapered shaft design along a single instrument in the shaft design 11,12) . And the design of cross-section of ProTaper -convex triangular -is claimed to reduce the contact area between the file and dentin, and to have excellent cutting efficiency 12) . It was claimed that the ProTaper system provides a continuous tapered preparation of the root canal, without significant transportation of the original curvature of the root canal 12) . And also it was suggested that the ProTaper instruments might be better suited for curved and constricted canals tha...

Section: ⅳ Discussionsupporting

confidence: 82%

Comparison of shaping ability using various Nickel-Titanium rotary files and hybrid technique

Kim

Park

Hur

et al. 2007

Self Cite

“…It seemed that enlarged coronal canal by crowndown usage of Mtwo file would facilitate the access to apical canal and this could shorten the time lapse of each step in group MC than that of group MT. In other studies 14,24) to compare ProTaper and other instruments, instrumentation time with ProTaper was shorter than other systems under identical experimental conditions. But in this study, the Mtwo file showed shorter preparation time than ProTaper, regardless of using method of Mtwo file.…”

Section: ⅳ Discussionmentioning

confidence: 99%

“…In ProTaper system, tooth structure can be removed excessively when this instrument is left in the canal too long with its active design 21) . It is therefore of utmost importance to follow the manufacturer' s instructions and not to leave the ProTaper to prepare the root canal for longer than 1 second or not to use the ProTaper too much when reaching the desired working length 14) . This precaution would also be applied in Mtwo instruments of group MT in which showed more aberrations.…”

Section: ⅳ Discussionmentioning

confidence: 99%

“…Measurements were taken horizontally at eight different levels (1, 2, 3, 4, 5, 6, 7 and 8 ㎜) from the level of apical foramen ( Figure 3). These values were used to calculate the instrumented canal width and post-instrumented canal diameter 14) . The centering ratio was computed to evaluate the movement of root canal' s center after preparation.…”

Section: ) Centering Ratiomentioning

confidence: 99%

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Comparison of shaping ability between single length technique and crown-down technique using Mtwo rotary file

Lim

Park

Hur

et al. 2007

Self Cite

Comparison of shaping ability between single length technique and crown-down technique using Mtwo rotary file Ⅰ. INTRODUCTIONRoot canal preparation with nickel-titanium (NiTi) rotary instruments is easier and faster than with hand instruments 1) . NiTi instruments have two to three times higher elastic flexibility and a superior resistance to torsional fracture, compared with similar-sized conventional stainless steel instruments [1][2][3][4][5] . Also, rotary instrumen- The aims of this study were to compare the shaping effect and safety between single length technique recommended by manufacturer and crown-down technique using Mtwo rotary file and to present a modified method in use of Mtwo file.Sixty simulated root canal resin blocks were used. The canals were divided into three groups according to instrument and the manner of using methods. Each group had 20 specimens. Group MT was instrumented with single length technique of Mtwo, group MC was instrumented with crowndown technique of Mtwo and group PT was instrumented with crown-down technique of ProTaper. All of the rotary files used in this study were operated by an electric motor. The scanned canal images of before and after preparation were superimposed. These superimposed images were evaluated at apical 1 to 8 mm levels. Angle changes were calculated. The preparation time, weight loss, instrument failure and binding, canal aberrations, and centering ratio were measured. Statistical analysis of the three experimental groups was performed with ANOVA and Duncan' s multiple range tests for post-hoc comparison and Fisher' s exact test was done for the frequency comparison.In total preparation time, group MT and group MC were less than group PT. In the aberrations, group MT had more elbows than those of group MC and group PT. The binding of group MC was least and group MT was less than group PT (P < 0.05).Under the condition of this study, crown-down technique using Mtwo rotary file is better and safer method than single length technique recommended by the manufacturer. [J Kor Acad Cons Dent 32(4):385-396, 2007]

“…11 Treatment techniques and instruments have been effectively evaluated in randomized controlled studies. [12][13][14][15][16] However, the special prospective cohort study models have been proposed to assess the outcome of endodontic treatment and elucidate the effect of various preoperative factors on the outcome in several studies. [7][8][9][10] A conspicuous aspect of these studies was the identified inception cohort, standardized treatment procedures, and data recording at the start of the study.…”

Section: Introductionmentioning

confidence: 99%

Prognostic factors influencing clinical outcome of nonsurgical endodontic treatment

Kim

2010

Objectives: This study aimed to assess prospectively the clinical outcome of nonsurgical endodontic treatment and identify patient-and tooth-related factors, rather than treatment-related factors, that were the best predictors of this outcome. Materials and Methods: The inception cohort comprised 441 teeth (320 patients) and 175 teeth (123 patients) were followed up for 1-2 years. Age, gender, presence of medical disease, number of canals, previous endodontic treatment, presence of sensitivity and pain, pulp vitality, swelling or sinus tract of pulpal origin on the gingiva, periapical radiolucency and tendency of unilateral bite on the affected tooth were recorded at treatment start. Results: The outcome was classified on the basis of periapical radiolucency as healed or non healed. The overall healed rate in these cases, including nonsurgical retreatment, was 81.1%. Four tooth-related factors had a negative impact in the bivariate analysis: previous endodontic treatment, necrotic pulp, preoperative gingival swelling or sinus tract of pulpal origin, and preoperative periapical radiolucency. Stepwise logistic regression analysis including patient-, tooth-related factors and level of the root canal filling as a treatment-related factor showed that preoperative gingival lesion (odds ratio [OR]: 4.4; p = 0.005), preoperative periapical radiolucency (OR: 3.6; p = 0.011), and ≤ 1-2 mm under root filling length (OR: 9.6; p = 0.012) were significant predictors of failure. Conclusions: A preoperative gingival lesion of pulpal origin can influence the outcome of nonsurgical endodontic treatment in addition to preoperative periapical radiolucency. [J Kor Acad Cons Dent 2010; 35(6):436-444.]