Effect of Different Speeds of Up-and-down Motion on Canal Centering Ability and Vertical Force and Torque Generation of Nickel-titanium Rotary Instruments

This study compared the torsional resistance of heat-treated nickel-titanium (NiTi) instruments under different temperature conditions. Four thermomechanically treated single-use NiTi rotary instruments were selected for this study: OneShape (OS), OneCurve (OC), WaveOne Gold (WOG) and HyFlex EDM (HFE). Each instrument was further subdivided by temperature into 2 subgroups. Maximum torque and the distortion angle until fracture occurred were evaluated. Differential scanning calorimetry analysis was performed to measure the phase transformation temperature. Statistical analysis was performed using a two-way ANOVA and t-test (p < 0.05). Fractured fragments were observed using scanning electron microscopy (SEM). The two-way ANOVA showed no significant differences for different temperature conditions. At both room (RT) and body temperature (BT), OS was predominantly austenite while HFE was martensite. OC and WOG were predominantly martensite at RT and mixed phase at BT. At BT, more than half of WOG was martensite, while half of OC was austenite. SEM examination showed no topographical differences between instruments in different temperature groups. In relation to a limitation of this study, there was no difference in torsional resistance of NiTi rotary instruments between the BT and RT conditions. This implies that clinicians do not need to consider a decrease of torsional resistance of heat-treated NiTi instruments at BT.

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Incidence of Dentinal Root Defects Caused by RECIPROC Blue, ProTaper Gold, ProTaper NEXT and RECIPROC Nickel Titanium Rotary Instruments

The Journal of Contemporary Dental Practice ◽

10.5005/jp-journals-10024-2512 ◽

2019 ◽

Vol 20 (3) ◽

pp. 291-297

Author(s):

Salsabeil W Hussien ◽

Hikmet A Al-Gharrawi,

Keyword(s):

Nickel Titanium ◽

Rotary Instruments

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Automatic Electronic Device Used for the Evaluation of Cyclic-Fatigue Resistance of Nickel-Titanium Instruments

Odovtos - International Journal of Dental Sciences ◽

10.15517/ijds.v0i0.27288 ◽

2017 ◽

Vol 19 (1) ◽

pp. 51

Author(s):

Cesar Gaitán-Fonseca DDS, MSc, PhD ◽

Edith Lara-Alvarado DDS, MSc ◽

Héctor Flores-Reyes DDS, MSc, PhD ◽

Amaury Pozos-Guillén DDS, MSc, PhD ◽

Verónica Méndez-González DDS, MSc

Keyword(s):

Human Factor ◽

Electronic Device ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Cycle Number ◽

Fracture Pressure ◽

Group Data ◽

Rotary Instruments ◽

Two Parameters ◽

Pressure Changes

The aim of this study was to evaluate the cyclic-fatigue fracture of different Nickel-Titanium motor-driven rotary instruments (ProTaper® Universal, ProFile®, and Mtwo® systems) in artificial canals by means of an Automatic Electronic Device (AED). The study was performed using Nickel-Titanium instruments 25/0.06 evaluated in canals with a 45-degree curvature and 2-mm radius. The analyses evaluated two parameters: fracture by cyclic fatigue, and time of fracture; in addition, the length of separated fragment was evaluated. Medians and range values were calculated for each group. Data were analyzed by the Kruskall–Wallis and Mann–Whitney U tests to determine statistical difference. The ProFile motor-driven rotator system exhibited highest resistance to fracture due to cyclic fatigue and highest fracture time compared with the ProTaper and Mtwo systems (p <0.05). The equipment proposed in this study (AED) demonstrated efficiency for recording information, automation, scheduled work times and durations, cycle number, time of fracture, pressure changes and, principally control of the human factor.

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Factors influencing incidents of complications while using nickel-titanium rotary instruments for root canal treatment

BMC Oral Health ◽

10.1186/s12903-019-0938-7 ◽

2019 ◽

Vol 19 (1) ◽

Author(s):

Ahmad A. Madarati

Keyword(s):

Root Canal ◽

Nickel Titanium ◽

Influential Factor ◽

Common Complication ◽

Pilot Studies ◽

Significance Level ◽

Rotary Instruments ◽

Chi Squared ◽

Final Questionnaire ◽

General Dentists

Abstract Background To investigate the complications associated with the use of nickel titanium rotary instruments (NiTi-RIs) for root canal treatments (RCTs), in Saudi Arabia dental practice, and to explore the influencing factors. Methods After obtaining an ethical approval, two pilot studies were conducted to formulate the final questionnaire. The sample size was measured taking into consideration 60% expected response rates and confidence level of 99.9%. The questionnaire was emailed to 600 general dentists (GDs) randomly selected from the dental register and all of the endodontists (175). The email’s introduction clarified objectives of the study and guaranteed that all of the collected information would remain confidential. A reminder was sent after 10 weeks. The data were collected and analyzed using the chi-squared test at a 0.05 significance level. Results With a 51% overall response rate, 71.9% off the respondents used NiTi-RIs. The majority (83.1%) experienced complications while using NiTi-RIs; with the instruments’ fracture being significantly the most common complication (52.7%) (p < 0.001). The majority (87.7%) experienced NiTi-RIs’ fractureat least once; with more endodontists (94.3%) than GDs (83.3%) (p < 0.001). The greater the number of weekly performed RCTs and participants’ experiences, the more NiTi-RIs fractures and the greater the number of fracture incidents (p < 0.001). While 60% of those who performed 1–3 RCTs per week experienced NiTi-RIs fractures, 100% of those who performed more than 12 RCTs per week did so. The highest percentage of those who experienced more than 10 fractured NiTi-RIs (60%) was within the group who performed more than 12 RCTs per week. Although fracture incidents decreased with a smaller number of reuses, there was no significant correlation between the number of fractured instruments and NiTi-RIs discard strategy (p ≥ 0.05). Conclusion Fracture incidence was the most common complication while using NiTi-RIs, regardless of the clinicians’ experiences and skills. While the single use may reduce NiTi-RIs fractures, to some extent, the greater number of RCTs performed per week was the most influential factor.

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