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...

Probably the strongest correlation we can make in endodontics is that short-term success is directly tied to the degree we eliminate bacteria from the pulpal space. It is reasonable to assume that in an infected case we are not removing 100% of the bacteria so it is reasonable to assume we must reach some threshold of reduction that tips the balance in favor of healing. It is also possible that our anti-bacterial and fixative agents as well as the sealers we use are neutralizing enough remaining...

A key component of endodontic instrumentation is irrigation, solutions used to remove the smear layer and open the dentinal tubules (17% EDTA) to digest remnants of pulp tissue and to kill bacteria (2-6% NaOCl). The effectiveness of the irrigants is proportional to the time in the canal as well as the volume introduced. The volume of irrigant that can be placed at any one time is determined by the space remaining in the canal when the instrument is also present. It is here we have a dilemma. Gre...

In 1970, we were at the tail end of silver point obturation. While they could be done well when the canals were properly shaped and properly fitted with a snug 02 tapered silver point, too often smaller silver points were placed that did not bind apically and were not well filled with cement laterally. The result was leakage and corrosion of the silver point producing a black sediment along the length of the canal. The leakage was further exacerbated by the fact that the cement was usually pa...

Most canals are oval, much thinner in the mesio-distal plane than they are in the bucco-lingual dimension. The presence of thin isthmuses connecting wider orifices provides spaces where pulp tissue and bacteria reside and unless widened to some degree (30/02) will not be of sufficient width to overcome the surface tension of the irrigants used to digest the tissue and kill the bacteria. Rotary NiTi more or less limited to producing a conical shape in the presence of highly oval isthmus-like...