2020. 2. 28. 23:28ㆍ카테고리 없음
Over the years, NiTi alloys have become indispensable materials in endodontic treatment. With technological advancements in metallurgy, manufacturers have attempted to produce instruments with enhanced features. In parallel with these developments, endodontic motors have undergone improvements in terms of torque control and kinematics that are adjustable in different directions.
This review presents an overview of the advancements in instrumentation kinematics and the effect of instrumentation kinematics on root canal shaping procedures and instrument performance. The literature search for this narrative review was conducted in Google Scholar, Scopus, PubMed and Web of Science using the keywords ‘kinematics and endodontics’ and ‘reciprocation and endodontics’. In addition, historical literature was searched using the keyword ‘nickel–titanium and endodontics’. Overall, 143 articles were included up to 2015. Literature search methodologyA literature search for this narrative review was conducted in Google Scholar, Scopus, PubMed and Web of Science using the keywords ‘kinematics and endodontics’ and ‘reciprocation and endodontics’.
Over 2000 articles were found. In addition, historical literature searching was conducted using the keywords ‘nickel–titanium and endodontics’. This resulted in the identification of over 10 000 studies for preliminary analysis. Articles unrelated to the endodontic instruments were excluded. The included articles were checked to identify further relevant literature. Overall, 143 articles were included up to 2015.Endodontic machine‐assisted instrumentation can be classified into five groups according to the instrumentation kinematics as follows: rotary motion, rotational reciprocating motion, vertical vibration plus rotational reciprocating motion, vertical vibration and rotary motion plus rotational reciprocating motion (adaptive).
Rotational reciprocating motionAfter reciprocation was first introduced in 1964 with the Giromatic system (MicroMega), various endodontic reciprocating handpieces have been manufactured (Prichard ). The Giromatic system, Endo‐Gripper (Moyco Union Broach, Montgomeryville, PA, USA), Intra‐Endo 3 LD (KaVo, Biberach, Germany) and Dynatrak (Dentsply DeTrey, Konstanz, Germany) operate with equal angles of 90° clockwise (CW) and clockwise (CCW) motion. Over time, the Giromatic system lost popularity because it produced greater procedural errors than hand filing (Weine et al. ).The M4 (SybronEndo, Orange, CA, USA), Endo‐Eze (Ultradent Products Inc., South Jordan, UT, USA) and Endo‐Express SafeSider (Essential Dental Systems, South Hackensack, NJ, USA) systems are current examples of reciprocating handpieces that utilize small, equal 30° angles of CW and CCW rotation. These handpieces enable the formation of an endodontic glide path using small stainless steel hand files (Gambarini et al.
).More recently, reciprocating motion regained popularity with the introduction of NiTi alloys and endodontic torque control motors. In 1985, a balanced‐force technique for curved canals was described by Roane et al. ( ) and included unequal CW and CCW motions with hand files. Yared ( ) introduced the concept of single‐file reciprocation, which was based on a balanced‐force technique and used the ProTaper F2 instrument (Dentsply Tulsa Dental Specialties) (a flute‐designed instrument with cross‐sectional geometry that aids in the cutting of the dentine in the CW direction) with unequal CW and CCW rotational motion (144° CW and 72° CCW).
This development meant that the instruments required five rotations to complete a full 360° rotation. At the same time, the elastic limit of the instrument was not exceeded due to this motion (Kim et al. ).Based on these developments, manufacturers introduced single‐file reciprocating systems including WaveOne (Dentsply Tulsa Dental Specialities) and Reciproc (VDW, Munich, Germany).
The major difference is that these instruments had a CCW cutting direction, so the instruments could cut if the CCW movement was greater than the CW movement. However, except for these reciprocating instruments, all of the instruments are designed for cutting in the CW direction. Rotary motion plus rotational reciprocating motion (adaptive motion)In 2013, a new endodontic motor was introduced by Sybron Endo (Elements) that aims to combine the advantages of both rotary and reciprocating motions. When the instrument is not (or is minimally) stressed, the motion can be described as a rotation of 600° in the CW direction, a stop and then a restart in the CW direction.
When the instrument engages dentine or the root canal filling, the motion of the instrument becomes reciprocal due to the increased stress. The reciprocal angles are not constant, and the motor modifies the CW/CCW angles from 600/0° to 370/50°, depending on the intracanal stress ( ). An overview of the asymmetrical rotary motion studiesAs mentioned previously, instruments having an off‐centred cross section (Revo‐S, ProTaper Next, new generation OneShape and TRUShape 3D Conforming Files) result in an asymmetrical rotary motion. However, there is no available study comparing instruments with similar cross‐sectional geometry and metal alloy to determine the effect of pure asymmetrical motion. Thus, further studies comparing instruments with similar cross‐sectional geometry are required to understand the effect of asymmetrical motion on debris extrusion, cutting efficacy, cyclic fatigue and root canal transportation. Reciprocating angleKnowing the actual reciprocating angles is important because it has been shown that decreasing the reciprocation range of the instruments results in increased cyclic resistance with less transportation but with longer preparation times (Saber & Abu El Sadat ).
According to the manufacturers, the ‘WaveOne ALL’ mode generates a rotation of 170° CCW and 50° CW, and the ‘Reciproc ALL’ mode generates a rotation of 150° CCW and 30° CW (Kim et al. Recently, Fidler ( ) investigated the kinematics of reciprocating motors using a high‐speed video camera and found that the actual angles of the WaveOne mode is 160° CCW and 41° CW, those of the Reciproc mode is 159° CCW and 35° CW, and those of ATR Technika's reciprocation mode is 1310° CW and 578° CCW.The ATR motors of two different models, the ATR Technika (old version) and ATR Vision (new version), were frequently used in previous studies (Yared, De‐Deus et al., Varela‐Patino et al., You et al., Paque et al., Stern et al., Perez‐Higueras et al., Giuliani et al., Kansal et al. ATR Technika has only one reciprocating mode, such that the reciprocating angles are not adjustable, whereas the ATR Vision has an option to adjust the reciprocating angles. In the first study on the single‐file reciprocation concept by Yared ( ), the ATR Vision was used, and the reciprocating angle was found to be four‐tenths (144°) and two‐tenths (72°) of a circle. Subsequently, ATR Technika was used in numerous studies, and conflicting angles (144°–72°, 60°–45°, 140°–45°) were reported, although reciprocating angles could not be adjusted with the motor (De‐Deus et al., Varela‐Patino et al., You et al., Stern et al., Kansal et al. Researchers should be aware of the actual angles of the reciprocating motion when undertaking further studies.
Cyclic fatigueThe cyclic fatigue resistance of single‐file reciprocating systems has been evaluated previously, showing that reciprocating instruments had higher cyclic fatigue resistance than did instruments that used rotary motion (Castello‐Escriva et al., Pedulla et al. Perez‐Higueras et al. ( ) reported that K3 (SybronEndo), K3XF (SybronEndo) and Twisted File (SybronEndo) instruments had better cyclic fatigue resistance when moved with reciprocating motion (144° CW and 72° CCW) compared to rotary motion. Similarly, Kiefner et al. ( ) evaluated the cyclic fatigue resistance of Mtwo (VDW) and Reciproc instruments under rotary motion or reciprocating movement (Reciproc All mode) and concluded that the reciprocating movement increased cyclic fatigue resistance.
Additionally, De‐Deus et al. ( ) reported the increased cyclic fatigue resistance of ProTaper Universal instruments under reciprocating movement (ATR Technika's mode). These results suggest that the cyclic fatigue resistance of different types of instruments (thermal treated or conventional NiTi) increases when using reciprocating motion.Gambarini et al. ( ) evaluated the effect of the reciprocating range on cyclic fatigue resistance of instruments and concluded that increasing the reciprocating range reduced resistance to cyclic fatigue. However, the rotational speed of reciprocating instruments may not be constant.
Electrical engines have mechanical limitations for converting the rotation direction, resulting in acceleration and deceleration in both directions of rotation (Kim et al. Gambarini et al. ( ) stated that the differences in the cyclic fatigue resistance of different reciprocating angles may be related to this acceleration and deceleration phenomenon.In a recent study, Shin et al. ( ) evaluated the effect of different periodic angular increments on an instruments' cyclic fatigue. The authors compared different stationary reciprocating motions (equal CW and CCW motion) and different progressive motions with different angular increments whenever an instrument completed different reciprocating cycles, a reciprocating motion similar to that used by Yared ( ) and rotary motion. It was found that a progressive reciprocating operation with a 45° reciprocating amplitude and a +7° progressive angular increment every 10 reciprocating cycles increased the cyclic fatigue life by 990% in rotary motion (Shin et al.
Moreover, according to Shin et al. ( ), the use of the progressive reciprocating motion caused multiple fatigue crack initiation sites, whereas rotary motion and stationary reciprocating motions caused single crack initiation sites. Changing the stress point on the instruments with different angular increments appears to be a promising development in endodontic motors. Torsional fatigueRecently, Kim et al. ( ) investigated the torsional resistance of single‐file reciprocating instruments and showed that the rotation angles at the beginning point of the plateau, which implicate permanent distortion, were 170°.
The authors concluded that both single‐file reciprocating instruments should be relatively safe when operated with their own motions because the rotational deformation can be recovered upon unloading (Kim et al. Further studies will be needed to investigate the effect of reciprocating motion on the permanent deformation of different brands of NiTi instruments. Life spanVarela‐Patino et al. ( ) reported that root canal preparation using ProTaper Universal files with full‐sequence reciprocation motion of ATR Technika motor resulted in a higher mean life span of the instrument compared with using the same instrument and full sequence with rotary motion. Moreover, You et al.
( ) showed that the use of single ProTaper F2 instruments with the reciprocating motion of the ATR Technika motor resulted in similar root canal transportation but shorter preparation time in curved canals compared with a full sequence with rotary motion. It also has been reported that a single F2 file can be used safely in curved canals at least six times with reciprocating motion (You et al. Recently, Plotino et al. ( ) investigated fracture incidence of the Reciproc instruments after clinical use and showed that the fracture incidence of the Reciproc instruments (single usage) was 0.47%. Similarly, Cunha et al. ( ) reported that the instrument fracture incidence was 0.42% of the teeth enlarged with the reciprocating WaveOne instrument.
Based on these results, the file fracture incidence of reciprocating instruments is lower than that of rotary instruments (Ramirez‐Salomon et al., Wu et al., Ehrhardt et al.
The invention is an endodontic handpiece, its control system and method of use for rotating an endodontic file to clean a root canal. The invention control system provides for rotating a file clockwise or counterclockwise through a desired first arc of rotation and, next, sequentially rotating the instrument in the opposite direction of the first arc of rotation through a second arc of rotation, wherein the first arc of rotation exceeds the second arc of rotation such that sequentially occurring rotations cause debris material removed in cleaning the canal to be ejected upwardly from the clean surfaces as such file is advanced in cleaning the canal. 9-11-02Garman45231999-08-31Badoz44411999-08-17Brenner41051999-05-11Uejima et al.4361997-06-17Martin48861996-12-24Roane40341996-10-29Meller et al.44231996-07-23Coss et al.4191992-03-17Kobayashi et al.4341991-05-21Saito et al.4391990-03-27Jacklich46531989-05-30Edwardson48551988-09-27Levy44261986-12-16Levy45081986-09-16Roane831986-02-18Nash43561985-10-01Gardella et al.48491981-09-15Lustig et al.45291977-02-15Fleer5-08-26Landgraf et al. 'Torsional Properties of the Canal Master Instrument'; Gary R.
Massa et al., Journal of Endedentics vol. 5, May 1992.'
Hakan Arslan
An Evaluation of the Canal Master, Balanced-Force, and Step-Back Techniques'. Hankins et al., Journal of Endodontics, vol. Comparison of Root Canal Preparation Using Different Automated Devices and Hand Instrumentation'; Michael Hulsmann et al. Journal of Endodontics, vol.
Histologic Evaluation of Three Endodontic Instrument/Preparation Techniques'; M.L. Zuolo et al.; University of Iowa College of Dentistry; Published Jan. Histomorphometric Comparison of Canals Prepared by Four Techniques'; J. Craig Baumgartner et al.; Journal of Endodontics, vol.
What is claimed:1. BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates to a handpiece for rotating endodontic files to clean and enlarge root canals of teeth. More particularly, the invention focuses upon a handpiece and its control system and method of use that improves debris removal while reducing risk of file breakage.2. Description of the Prior ArtA key procedure in endodontic therapy of treating an infected tooth is cleaning and enlarging tooth root canals of the tooth prior to filling with an inert obturating material such as gutta percha. Such a procedure wherein infected tissues are successfully removed from the tooth greatly improves the likelihood that a patient will retain the tooth rather than need to have it extracted. The procedure for debridment and cleaning of infected material from the canal and to properly shape the canal to receive the obturating material is time consuming, generally employing a series of endodontic files that are rotated and advanced into the canal to clean canal surfaces and eject the debridment material from the canal for removal.In the past, endodontic files were employed by the dentist manually, a very tedious process requiring substantial skill.
It soon became evident that employing a handpiece to mechanically duplicate hand techniques, including rotating a file, would be a beneficial improvement in efficiency. However, a difficulty with motorized rotation or engine-driving of files is that the dentist sacrifices his 'feel' and control of the procedure. The files are typically provided with helical cutting edges, presenting a danger of threading or screwing into the canal surfaces. Under such conditions a file, in negotiating tight curves or other root canal irregularities, might 'lock up' and be subjected to excessive torque that could cause the file to fail by breaking.
Torque
Additionally, rotation of instruments around a curve produces internal stresses resulting in metal fatigue that may cause a file to fail by breaking. Metal fatigue is induced more rapidly as the degree of curvature increases and/or the radius of the curve decreases. Such damaging results may require an extremely difficult effort at extraction of the broken file or other remedial action, including even extraction of the tooth. The dangers of lateral perforation, straightening, zipping and ledging are also all enhanced by engine-driven instrumentation.Various rotary handpiece designs and techniques for using them have developed, some focused upon varying the motion of the files from simple rotation to reciprocating eliptical patterns, in the effort to duplicate hand operating procedures.
Atr Technika Endo Motor Manual Pdf
Other handpiece improvements have focused upon controlling engine parameters, particularly by reducing speeds of rotation, setting limitations on torque applied to the file and the like to avoid file breakage.An earlier limitation of the overall endodontic preparation process was lack of flexibility of files, which tended to discourage engine-driven procedures altogether, particularly with respect to aggressive K-files. New file designs, including for example radial landed cutting edges, that avoid screwing-in and which are made of highly flexible nickel-titanium alloys present new opportunities for engine-driven procedures. These files will better follow root canal curves, but even so may be at risk of metal fatigue as they rotate in curved canals.