Quality Resource Guide

A Guide to Contemporary Endodontic Technology 4th Edition

www.metdental.com

EdgeFile, EdgeTaper, EdgeEvolve and

EdgeSequel (EdgeEndo)

These files are designed to simulate the design

and efficacy of other file systems, but are offered

at lower cost. Little objective research is available

to evaluate the efficacy of these instruments.

Because of the variety of systems available,

the dentist is frequently uncertain as to which

system he/she should use. Generally speaking,

dentists should consider the volume of endodontic

therapy in their practice, and whether they are

treating moderately difficult cases, such as molars,

or only simple cases. For dentists who treat

only simple cases with straight large canals,

rotary instrumentation will probably not offer them

significant advantages. For dentists who perform

more demanding cases, they should use systems

which have been evaluated objectively and found

to yield reliable results, and not just rely on

manufacturers’ claims. The dentist should request

from manufacturers literature on objective data,

which have been published in referred journals.

Specifically, data on the incidence of instrument

separation, maintenance of canal shape following

instrumentation and effectiveness of apical

preparation should be sought. Manufacturers

usually emphasize the speed of preparation, and

the number of instruments needed for completed

preparation; however, from a clinical effectiveness

perspective this data is usually not useful. Cost

is another important factor. The reduced number

of repeated use for these instruments should be

factored into the cost calculation. Studies have

shown that the Twisted File (SybronEndo) and

ProFile Vortex or Vortex Blue (Dentsply-Sirona)

have superior cyclic fatigue (delayed failure with

continuous rotation) and flexibility when compared

with similar sizes of older systems such as

ProFiles and Endo Sequence.

44-48

However, one

paper showed that Twisted Files have reduced

torsional stress resistance (less absolute strength

in rotation) compared to other systems.

It is

important to note that these in vitro studies are

preclinical in nature, and the true performance

of most of these systems clinically is currently

unknown.

Reciprocating Files

Reciprocating files follow the principle that the

use of watch-winding motion can be extended to

allow a motor to engage an instrument with high

taper in the canal so that it can incrementally be

advanced throughout the entire working length.

This concept was introduced in technique paper

in 2008.

This concept is very attractive, because

it has been known for a long time that reciprocal

motion significantly reduces the chance for binding

of the instrument, allow efficient negotiation, reduce

torsional stresses and instrument failure due to

cyclic fatigue. Thus, one instrument can potentially

be used to instrument the root canal, with fewer

chances for separation and operation that is

more efficient. Two main reciprocating systems

are available: WaveOne (Dentsply-Sirona, USA)

(

Figure 4

) and Reciproc (VDW, Germany). When

the instrument is activated it rotates a fraction of

a turn (exact amount differs between instruments)

in a clockwise direction and then a smaller fraction

of a turn counter clockwise. This results in a net

advancement of the turn in a clockwise direction.

However, the counter clockwise component

assures that the instrument does not bind, thus

reducing torsional forces etc. The TF Adaptive

system by Sybron Endo is designed to allow

reciprocation if there is resistance in the canal, and

rotation if there is no resistance.

Preliminary bench top experiments show these

instruments to meet the criteria from a metallurgical

and functional perspective. However, treatment

outcome studies are not available for them yet.

Moreover, a significant limitation of this concept is

the lack of apical preparation of the root canal as

discussed previously. Thus it is not clear whether

the use of one instrument (typically it is a size 25

at the tip) would allow adequate debridement of the

apical microbial biofilm.

Root Canal Disinfection

As noted before, there are two distinct diagnostic

categories of endodontic pathosis that affect the

prognosis: cases with vital (albeit inflamed) pulp,

Figure 3

a) XP-endo Shaper, b) XP-endo Finisher (Brasseler) and c) TRU Shape file (Dentsply-Sirona)

Figure 4

Motor and files for the WaveOne System (Dentsply-Sirona). The instruments are sizes 20/06, 25/08

and 40/08, each intended for use as the single instrument for the tooth/or canal involved.