I clinical report _ shaping system Fig. 6 through a #20 before rotary NiTi is used, we can dispense with instrumentation through a #20 for both approaches because the number of instruments is common to both. In reality, the glide path through a #20 with both non-relieved and relieved K-reamers will be dramatically easier and more rapid than K-files, but it is the use of the same relieved reamers in larger dimensions that negate the need for rotary NiTi. After the #20 relieved reamer is used, the coronal curve is straightened with a tapered peeso called a Pleezer. It is used only until resistance is met and never closer than 6 mm from the apex, even if possible. The use of a Pleezer would be similar to the use of a rotary NiTi instrument employed in a crown-down fashion, except the Pleezer is made of stainless steel with a far greater capacity to remove tooth structure from the outer wall of the canal, thus providing straight-line access for the subsequent instruments. Once straight-line access has been attained with the Pleezer, the #25 relieved reamer is taken 0.5 mm beyond the constriction, followed by the #30 to the constriction. At this point, if the canal was tight to begin with and highly curved, the final instrument would be a 25/.06 reamer 0.5 mm beyond the constriction, followed by obturation of the canal. In order to gain a canal preparation of a #30 at the apex, the minimum preparation stated in the literature to ensure adequate irrigation and a 25/.06 overlayed taper requires four instruments beyond the #20. This preparation compares favourably with rotary NiTi that often will not shape a curved canal to more than a 20/.04 or at most a 25/.06 to the apex, dimensions that do not fulfil the minimum preparation for effective irrigation as suggested by research. If the canals are larger, shaping may be continued with the #35 after the #30 to the apex with the #40 1 mm short and the 25/.06 used at this point. Even these larger preparations require no more than six instruments and are rarely ever needed in recapitulation, the way rotary NiTi instruments must be used. The system sounds too good to be true. The claims are that the system is able to shape highly curved canals without distortion, that canals can be shaped to a minimum diameter of #35 in most cases and that the instruments will not break, that they can be used six to seven times and overhead will diminish by approximately 90 % when switching from a rotary NiTi system to one using relieved reamers both manually and in the reciprocating handpiece. Where is the proof for these claims? Fig. 7 requirement becomes increasingly essential with increasing curvature of the canal. The short arc of motion keeps the K-reamers well centred within the confines of the canal. Distortion will only occur in curved canals if the arc of motion is significantly increased. This cannot happen when a reciprocating handpiece is used and is unlikely to happen with manual use simply because canals of increasing curvature produce dramatically more resistance to rotation, making the short arc of motion far more achievable. In fact, customising a short arc of motion, where the greatest resistance is encountered, is entirely compatible with distortion-free shaping. These two insights eliminate the need for rotary NiTi entirely and in doing so, eliminate the concerns for separation either through torsional stress or cyclic fatigue. While this sounds good, are there drawbacks? Does this system require many more instruments and can they be used efficiently? If one considers the reality that most glide paths are first created with difficulty using K-files 14 I roots 4_ 2009