Clinical
endodontics H
Reciprocation – the future of
An evolution in reciprocation is making the process smother and safer, believes Mark Haigh
aving used many systems for canal preparation over a 25-year span, the practical advan-
tages that the new concept of reciprocation brings over its predecessors has taken the art of canal shaping to a new level. How many practitioners
over decades have cursed their instruments used for canal preparation, whether it is the time taken, effectiveness, transportation, ledging or any other problem that confronts them when matters are not proceeding smoothly?
So what is this new evolution and where is its history? The ‘balanced force concept’, with its small clockwise and counter-clockwise move- ments, was developed more than a decade ago after Roane proposed it in ı985. Balanced forced technique is an addi- tional aid in shaping curved canals with larger diameter hand instruments, but these stainless steel instruments do very little for morale, day-in day-out in practice. Continuous rotary prepa-
ration with nickel-titanium (NiTi), of which most of us have some experience, does not allow us to fully prepare canals
54 Scottish Dental magazine
without the usage of some hand filing. So it was in 2008 that, after much researching, Dr Ghassan Yared (then professor at the University of Toronto) published a clinical article that had a dramatic effect and raised a few eyebrows – ‘Canal preparation with only one reciprocating instrument without prior hand filing: A new concept’ (
bit.ly/rY9xcw). This means the instrument
is driven first in a cutting direction, then reversed and the instrument is released. The angle in the cutting direc- tion is greater than the angle in the reverse direction, thus the instrument continuously progresses towards the apex. Having spoken to many of
my colleagues, they are still not comfortable in using NiTi rotary instruments to prepare canals. So, for those who are reluctant, the use of one recip- rocating file will put a sparkle back into endo and save both in cost and time. There are three instruments
marked with their specific ISO colour for easy identification: ı. R25 – has a diameter of 0.25mm at the tip and an 8 per cent taper over the first 3mm from the tip. 2. R40 – has a diameter of 0.40mm at the tip and a 6 per cent taper over the first 3mm
from the tip. 3. R50 – has a diameter of 0.50mm at the tip and a 5 per cent taper over the first 3mm from the tip. The instruments are made
from an M-wire NiTi giving resistance to cyclic fatigue and greater flexibility, more so that traditional NiTi. The cross section is S-shaped. The new system includes
a motor (VDW SILVER RECIPROC Endo motor, Munich, Germany). The menu can be pre-programmed for reciprocation (RECIPROC) and for continuous rotary systems e.g. ProTaper, K3, TriNiTi and Mtwo. Torque and speed settings can be set and stored and the motor also has built-in automatic reverse rotation if the set torque limit is reached. For obturation, matching
gutta-percha cones are included and matching paper points are also supplied with the intro kit. The single instru- ment for usage is selected based on a preoperative radio- graph and a hand-file canal orientation. If, on the radiograph, the
canal appears clear from access cavity to apex, use a size 30 hand instrument and insert gently with a watch- winding action to working length. If
Reciproc R25
file combining matching Paper and GP point
the size 30 hand file does not reach working length, retrace this step with a size 20. If the size 20 is inserted to working length (WL), use the R40 (medium canal). If it does not reach the WL, use the R25; if the size 30 hand file does reach the WL, then use the R50 (Large canal). In reciprocation, the clock-
wise/counter-clockwise angles are lower than the angles at which the RECIPROC instru- ment would usually fracture on binding. If a reciprocating file binds in the canal, it will not rotate past its angle of fracture,
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92