Does Progress In Endodontics Always Have To Be More Expensive?

?Have the more expensive tools given us superior endodontics. When an expensive system arrives it is touted by all means of marketing with little attention given to inexpensive, but effective alternative means of treatment. It is almost like and maybe not almost like our economy is structured to only advance those options that create more expensive choices with the thrust to justify those expenses being the unstated impetus of marketing. Anything simpler and less expensive is derided as “old fashion”, yesterday’s technology or lacking in scientific support even though that may not be the case at all. If it were, there would be definitive proof that the new more expensive methods are producing higher success rates, studies that have yet to see the light of day. This post covers instrumentation, obturation and irrigation the cornerstones of contemporary endodontics.

When I started out in endo about 50 years ago, there was a touch of envy from other specialists because endodontics required the least expensive armamentarium of all the specialties, some stainless steel hand reamers (or files), peesos and gates gliddens, gutta percha points, sealer, a spreader, some pluggers and a Bunsen burner, all pretty inexpensive items.??The reamers costing about 60 cents each could be sterilized and used several times before replacement and a box of 120 gutta percha points cost about 7 dollars. Things pretty much remained that way until the introduction of rotary NiTi, instruments that cost about 10 to 15 times more and were recommended for single usage before replacement making them even more expensive.?

Rotary endodontics offered an alternative to the total manual shaping of the canals reducing hand fatigue and the procedural time required. Interestingly, the first rotary system had the same tight horizontal flute configuration as K-files. It was also the last rotary instrument with a file design, all subsequent instruments were reconfigured to that of the more vertically oriented reamer design. One would have thought that the reamer design so necessary for rotary endodontics to work would have influenced K-file users to switch to K-reamers for the initial glide path creation, but that insight was overpowered by the tradition of their long term use without any guidance from rotary advocates who were now using and teaching the use of rotary NiTi instruments with a vertically fluted reamer configuration. They seem to have simply not noticed.

Along with the higher costs of rotary NiTi, the engines that drives it and their more rapid replacement compared to the manual use of stainless steel K-files, rotary required an increasing number of precautions in their usage as canal anatomy became more complex. One of these precautions, staying centered, resulted in inadequate debridement and cleansing in the wider diameter of oval canals with many studies documenting this inadequacy. While manual instrumentation was much slower and produced high degrees of manual fatigue, instrument separation could easily be avoided by employing short arcs of back and forth motion (watch-winding) coupled to the occasional pull stroke to shave away the engaged dentin. It was slower and took more work, but was safer and did not require as many precautions as canal anatomy became more complex. With the arrival of rotary NiTi instrumentation, we saved time, unless the instrument separated, but we paid 10 to 15 times more for their usage and we were left with inadequate results when complex oval canals were being treated.

The inadequacy of three-dimensional cleansing in oval canals, a result of the need to avoid rotary instrument separation, has led to the innovations of laser activated irrigation systems costing in the tens of thousands of dollars to compensate for a system that creates these conditions. Each iteration of more “progressive” instrumentation increases the expenses many times over the previous costs for the stated purpose of becoming more efficient and effective. Rotary replaced most of hand filing speeding up the instrumentation process and minimizing hand fatigue and produced smooth greater tapered images on x-ray that were interpreted as a superior result without any corroborating evidence that it leads to a higher success rate. Laser activating units costing in the $40,000 to $80,000 range are now being viewed as an answer to the inadequacies of three-dimensional debridement and shaping provided by rotary systems when instrumenting oval canals.?

Interestingly, it turns out that the simplest and least expensive original stainless steel systems are the most adaptable to improvement with the least potential to drastically increase costs. By switching from K-files to K-reamers, the ability to shave dentin away from the canal walls is improved, the resistance in negotiating to the apex is reduced and the chances of impacting debris apically and losing length are greatly diminished. Furthermore, by mechanizing the manual watch winding motion with a 30o oscillating handpiece the original problems of hand fatigue and excessive procedural time requirements are overcome.??To??improve their function, the reamers incorporate a flat along their entire working length further reducing resistance, making them more flexible and adaptable to the canals they are negotiating through even when significant curves are present. This is a form of improvement that does not result in a great increase in costs and due to the short arcs of motion driving the system makes it much safer to implement.

30o oscillation obviously goes against the trends innovated by the large manufacturers. Reducing costs and doing away with the need for evermore complex and expensive systems is not in their plans. They look at 30o oscillations as a technique that should never have come along, an unexpected negative event that must be disparaged and treated as old technology??to convince as many dentists as possible to ignore its attributes. That is the beauty of linkedin. The message is out there and all dentists have to know is that it is a viable option that they can try and render their own judgment.

Let’s talk a bit about obturation. 50 years ago, I would take a point corresponding to the shape I made with the K-reamers (that’s what I was using 50 years ago) to fill the space after first flooding the canals with a zinc oxide-eugenol cement applied with a K-reamer into the canal with the reamer manually rotating counterclockwise. I then coated my prefitted gutta percha point, put it to place in the canal and seared off the excess gutta percha with thin heated plugger. When the canals were quire oval or c-shaped, I would add coated accessory points after creating a lateral space with a spreader. It worked fine for years. Being a room temperature system it was dimensionally stable perhaps expanding a bit as the cement and gutta percha point warmed from room temperature to body temperature. While the room temperature gutta percha was minimally adaptable to the canal walls, the zinc xide eugenol cement was more flowable than a heated gutta percha point could be and easily filled the interface between the canal walls and the gutta percha point.

The fact that we used particulate cements like zinc oxide and eugenol, cements that are soluble in the presence of moisture presented an opening for the expensive introduction of a myriad of thermoplastic systems with carrier based points costing about $6 to $7 a piece as opposed to a box of 120 gutta perchapoints costing $7. The reasoning is as follows: since the cements can dissolve in the presence of moisture it become mandatory to fill as much of the space as possible with gutta percha and the best way to do this is thermoplasticize it and place it into the canals under pressure assuring close adaptation to the canal walls.??

That is one approach and an expensive one. Another option is the direction we took. Simply replace the particulate cement being used with an epoxy resin cement, a form of AH26 that has been around for over 70 years that is entirely resistant to dissolution in the presence of moisture. Any gaps between the gutta percha point and the canal walls filled with the epoxy resin cement remain stable and intact bonding to both the canal walls and the gutta percha point chemically and physically. Once again doing away with the need for ever more expensive products to replace minor shortcomings that can easily be overcome with a minimum of ingenuity.

It’s all about the mindset and your personal agenda. I want the simplest most predictable way to perform endodontics for myself personally and as a small company I believe this approach appeals to any dentist who takes the time to give it some thought. Having been exposed to the ever more expensive products being introduced by the major manufacturers for so many years, I believe I am on the right track both practically and morally.?

Regards, Barry