Ever since the introduction of rotary NiTi we have been sold on the benefits of greater tapered engine-driven shaping. It has reduced hand fatigue and created smooth conical shaping even in curved canals where the previous use of manual K-files alone often produced blockages, ledges and loss of length. The advantages of these engine-driven greater tapered systems are often increased speed in canal shaping and a look that we have been taught to believe is superior to the way canals were previou...

When confronted with an angled access to a canal orifice, is attaining straight-line access good for the tooth, the instrument that will negotiate the canal or both? At one time, what was considered good for the instrument equated with what was good for the tooth. That symmetry is no longer taken for granted. Certainly, straight-line access along with preflaring reduces the stresses a greater tapered rotary instrument will encounter in turn reducing the incidence of instrument separation. That...

      When shaping canals it is axiomatic that we are attempting to gain access to a pathway to the apex that is at least to some minimal extent open. Given the curved nature of canals and their tendency to calcify with aging this can often be a challenging task. While reaching full length can often be a difficult task to achieve, this difficulty cannot be used as a rationalization to limit the instrumentation of the canal to conical shaping. Without doubt conical shaping will remove mo...

 Most roots are wider in the bucco-lingual plane than the mesio-distal plane. This asymmetry is reflected in the pulpal anatomy. Pulpal tissue is most often quite thin mesio-distally, but often quite broad bucco-lingually. Yet, despite this fact, canal preparations are widened broadly in the mesio-distal plane where the roots and the pulp tissue are thin and inadequately instrumented in the bucco-lingual plane where both the roots and the pulp tissue are wider. In short, creating a canal prep...

What criteria do we use to determine the safest, most efficient and most effective way to perform endodontics given our present state of technological skills? Do we want to make a minimal preparation that sacrifices as little dentin as possible assuming the tooth will retain more of its preoperative strength? Doesn’t that leave open the possibility that we will not cleanse the canal as well leaving tissue and bacteria as continuing sources of breakdown? On the other hand, won’t greater tapered p...

I watched a video posted on linkedin recommending the use of rotary instruments over reciprocating systems primarily because the speaker stated that reciprocation pushes more debris over the apex. It should be added, that the version of reciprocation he was referring to was asymmetric meaning it rotated more in one direction than the other leading to interrupted, but full rotations. The consequences of full rotations are a greater potential for instrument separation. Interrupted rotations redu...

To appreciate proper endodontic shaping and obturation, one must have a thorough understanding of pulpal anatomy in the teeth we may be asked to treat. I am providing a link to Versiani, Pecora and Neto, three researchers who have done extensive micro-ct analysis of pulpal anatomy and the many configurations it can take. Once you hit the link, go to the videos on that page and then follow up by clicking on a list  on the left of the screen to see other videos showing the anatomy of all the teeth...

The above x-ray looks good enough not to have periapical breakdown. The cross section, unseen on x-ray, tells us why pathology remains. It has been about 25 years since the introduction of greater tapered rotary shaping. This technology was and is considered a major advance over the manual use of K-files coupled to the use of gates glidden and peeso reamers. NiTi allows instruments to have greater than 02 tapers while retaining flexibility along the thinner portions of their length. Rotary re...

We must preserve as much tooth as possible consistent with rendering the tooth as free of bacteria and the tissue that supports bacterial growth as possible. Any other reason for removing tooth structure is counterproductive, particularly applied to straight-line access, preflaring and crown-down preparations for the sake of reducing the incidence of instrument separation. We must employ techniques of tissue and dentin removal that are as benign as possible. The removal of dentin and tissue...

The product is being introduced at the Chicago mid-winter meeting. It is essentially two instruments (It takes two to Tango). They consist of a 30/02 stainless steel relieved reamer design and a 30/04 relieved NiTi. They have an s-shape cross section and are used in a 30º latch-type handpiece. They are to be used only in the reciprocating handpiece. If they were used manually and rotated beyond 30º, something that is possible if done manually they would be subject to separation. Used in the reci...