Endodontics Posts

Tooth Isolation. The Rubber Dam, suggested or obligatory?
Arnaldo Castellucci

The Self-Adjusting-File (SAF) Technique
Francesco Bellucci Zvi Metzger

Root Canal Irrigation in Modern Endodontics: Complex Cases
Filippo Santarcangelo Arnaldo Castellucci

Root canal irrigation in modern Endodontics. Part one: the routine
Filippo Santarcangelo Arnaldo Castellucci

Micro-surgical Endodontics. The State of the Art
Arnaldo Castellucci Matteo Papaleoni

The Pathfiles: a new series of rotary Nickel Titanium instruments for mechanical pre-flaring and creating the Glide Path
Giuseppe Cantatore Elio Berutti Arnaldo Castellucci

The new GT SERIES X rotary shaping system
L Stephen Buchanan

Tetraclean: A contribution to root canal cleaning
Luciano Giardino

Nickel Titanium (Ni-Ti) Endowave Morita instruments
Giorgio Uccelli

Tooth Isolation. The Rubber Dam, suggested or obligatory?

Tooth Isolation. The Rubber Dam, suggested or obligatory?



The need to work under dry conditions, free of saliva, has been recognized for centuries, and the idea of using a sheet of rubber to isolate the tooth dates exactly 153 years! The introduction of this notion is attributed to a young American dentist from New York, Sanford Christie Barnum, who in 1864 demonstrated for the first time the advantages of isolating the tooth with a rubber sheet.

The Self-Adjusting-File (SAF) Technique

The Self-Adjusting-File (SAF) Technique




In 1993 the first  endodontic files, made from a nickel-titanium (NiTi) alloy,  were introduced to the dental market and definitely contributed to a radical change in the operative approach to endodontic treatment   [1]. Compared to  previous stainless steel  files, they were much more flexible,  effective and better performing in shaping   root canals. Furthermore, in recent years, advances in knowledge and technology  have  brought about  several  interesting changes in these alloys, which were made increasingly resistant to  torsional load and, therefore, safer to use.This has led to the manufacturing of  a “single file” ,  which  enables dental practitioners to shape the full length of the root canal using a single  instrument, such as  Wave One ® (Maillefer- Dentsply , Ballaugues, Switzerland) or Reciproc ® (VDW, Munich, Germany) [2].Despite these structural improvements, the file design has remained unchanged :  a solid body with more or less sharpened blades, which cut the canal from different angles and  collect treatment debris in their flutes. This suggests that, despite the different endodontic  variations recurrent in nature, we do nothing but imprint the instrument shape inside the canal, regardless  canal anatomy ; this apparently allows us  to use similar procedures with either round-shaped  and oval- shaped canals ,  as well as with  more or less tightly curved canals.From the studies carried out by  Paqué [3,] analyzing  MicroCT  sections, it is clear  that instrumentation with conventional Ni-Ti tools   does not allow  us to accomplish  a proper cleaning of the whole root canal system (fig.1). In fact, these instruments, due to their  shape, cannot contact the entire surface  of root  walls, thus  leaving within a certain amount of unremoved tissue, which also reduces the quality of subsequent obturation ,  as  highlighted by De Deus (Fig2) [4.5].

Root Canal Irrigation in Modern Endodontics: Complex Cases

Root Canal Irrigation in Modern Endodontics: Complex Cases



Anatomy: A Daily Endodontic Challenge

In my first years as a dentist, before completely dedicating myself to endodontics, I practiced all the dental disciplines. I performed extractions, amalgam restorations, composite resin restorations, crown preparations, surgical flaps and scaling. By doing this I could visibly check the working area (gingiva, core preparation, cavities before filling etc, etc) and thus I could directly verify the work as it evolved.

With endodontics I could not do this.

Even with radiology, magnification and the microscope, endodontics of the last few mm is always “in the dark” (especially with molars) meaning that we cannot for instance directly observe a K-file working as it files the apical third.

Its substantial difference from other disciplines of dentistry along with large anatomical variations and the complexities of the root canal system attracted me to this mysterious and fascinating discipline.

I decided to dedicate myself completely to endodontics. As time went by I became convinced that practicing endodontics is a daily challenge against the hidden and unpredictable microanatomy. Maybe this is what makes endodontics so attractive!

Now, after years of endodontics, I have a clear concept of complex anatomy and it seems limiting at this point to talk only of narrow, curved or long canals.

Root canal irrigation in modern Endodontics. Part one: the routine

Root canal irrigation in modern Endodontics. Part one: the routine




Why do we irrigate?

Successful endodontic treatment, in agreement with what Prof. Schilder, the father of modern endodontics, enunciated, depends on the ability of the operator to mechanically and chemically clean the root canal system and subsequently obturate it three dimensionally.1

The endodontium consists of a space that is easily accessible to rotary and manual instruments (principal canals) and, as has been confirmed by numerous clinical and histological studies, there are spaces that are difficult to access or completely inaccessible (deltas, loops, isthmi, lateral and accessory canals, and dentinal tubules).

In particular lateral and accessory canals are found with significant frequency especially in the apical third of the root and in molar bifurcations.

Canal shaping is unable to reach some areas and they remain untouched by the instruments, no matter what technique is used; thus about half of the endodontium remains untreated.2

The complexity of the endodontium could, however, be one of the determining factors in failure of root canal treatment even in properly treated teeth, due to irregular and sometimes unpredictable spaces that characterize root canals.3-4

In the light of the above one of the most exciting challenges of modern endodontics is represented by the biochemical debridement of the endodontium (accessible and non accessible).
When debridement is performed according to the state of the art (three dimensional) cleaning, the endodontium can then be filled and sealed with cement and gutta-percha at the time of obturation.

Irrigation, therefore, plays a crucial role in determining the outcome of root canal treatment.

What irrigants should be used? A choice based on scientific evidence.
I remember back in my university days, I once took my father to his dentist, a general practitioner, as he had to have root canal treatment. I was particularly struck by the frenetic rinsing with a sodium chloride solution alternated with hydrogen peroxide and asked why this procedure was performed.

He answered that they had been taught to do it this way, without critically motivating his choice.

In every field of medicine, the clinical practitioner must follow logic and must be supported by literature.

Therefore, to rationally choose an irrigant you must first answer the question: “What do we want to remove from the canal?”
The answer is simple; we want to eliminate the organic tissue (pulp), bacteria and toxins, as well as organic and inorganic debris that our rotary and manual instruments inevitably produce.

At this point the choice is easy and natural.

Literature has highlighted sodium hypochlorite in a concentration of 6% as the irrigant of choice inasmuch as it is able to dissolve organic substances and eliminate the bacterial presence and the biofilm from inside the canal.5-10

Complete debridement is achieved by combining a substance capable of eliminating the inorganic component created after the instrumentation. It is
necessary to use a chelating agent namely 17% EDTA or 10% Citric Acid.11-14

A 2% Chlorhexidine aqueous solution has been suggested as an irrigant for the root canal system. This has an antibacterial action but lacks the ability to dissolve the organic and inorganic material.15-16

Furthermore mixing sodium hypochlorite and chlorohexidine generates a toxic and cancerous compound, parachloroanaline and its use as an irrigant is not recommended.17

Micro-surgical Endodontics. The State of the Art

Micro-surgical Endodontics. The State of the Art




By Surgical Endodontics one refers to that branch of Dentistry that is concerned with the diagnosis and treatment of lesions of endodontic origin that do not respond to conventional endodontic therapy or that cannot be treated by conventional Endodontic therapy. The scope of Surgical Endodontics is to achieve the three dimensional cleaning, shaping and obturation of the apical portion of the root canal system which is not treatable via an access cavity, but only accessable via a surgical flap (Fig. 1 a,b,c,d).

Apicoectomy surgical endodontics


surgical endodontics


For this reason it is preferable to use the term Surgical Endodontics rather than Endodontic Surgery, in as much as the procedure should be planned and carried out as an endodontic procedure via surgical access and not a surgical procedure done for endodontic reasons.
Once a diagnosis of Endodontic failure has been made, it is necessary to understand what the cause of the failure was so that successively the possibility of correcting the failure by orthograde retreatment can be evaluated. Only in the case where this possibilità does not exist or better still after failure of the non-surgical therapy carried out to resolve the problem, only then is one authorized to intervene surgically. Apical Surgery in other words is not a substitute for incomplete debridement and poor endodontics (Fig. 2 a,b,c,d).

The Pathfiles: a new series of rotary Nickel Titanium instruments for mechanical pre-flaring and creating the Glide Path

The Pathfiles: a new series of rotary Nickel Titanium instruments for mechanical pre-flaring and creating the Glide Path




Rotary NiTi instruments have revolutionised endodontics, allowing even the less experienced dentist to create perfectly truncated-conical shaping in harmony with the original anatomy, and improving the prognosis even of the most complex cases. Many “in vitro”1-13 and “in vivo”14-17 studies show quite clearly that the nickel-titanium alloy is greatly superior to stainless steel, since with NiTi instruments even canals with severe curvatures can safely be shaped without the risk of creating ledges or of straightening the original curves. Numerous studies 16,17 have shown that, with the use of NiTi, even the inexperienced dentist can obtain better results than by using stainless steel. However, the use of NiTi has one serious drawback, in that it carries a higher risk of the instrument’s breakage compared to stainless steel.18 The influence of various factors on breakage of rotary NiTi instruments has been extensively studied and it has been found that breakage usually depends on torsional 19-25 and on bending stresses.21-23,26,28

Bending stress essentially depends on the original canal anatomy, on the radius of canal curvature, the speed of rotation and the flexibility of the instrument, the presence of intra-canal interferences, sharp changes of trajectory, as for example occurs in the case of merging root canals. The endodontist can do very little to reduce this type of stress.

Torsional stress depends on numerous factors: the area of contact between the instrument blade and the canal walls, the pressure the operator exercises on the handpiece, the diameter of the instrument section and that of the lumen of the canal in which it is working, the taper, the diameter of the tip of the instrument, the portion of the instrument that is subjected to torsion, the intrinsic strength of the instrument (thus on the design of its cross section), the design of its blades, and lastly on the torsion applied to the instrument.27,28 In short, breakage occurs if the canal section is smaller than the tip of the instrument that cannot cut the dentine, and what is known as “taper lock” occurs. This is followed by plastic deformation and instrument breakage.

Analysis of NiTi instruments broken due to torsion shows that most breakages occur in the last few millimetres, where the taper is less and the diameter smaller.24,25,27,28 Consequently, the tip of the smallest NiTi files presents the highest risk of breakage due to torsion, from which it must be protected using a low torque value, reduced axial pressure and above all by avoiding the tip’s engaging against the dentine walls.

Numerous studies have evaluated the causes of breakage of NiTi instruments and have concluded that a marked reduction in the breakage rate of rotary instruments can be achieved when their use is preceded by preliminary manual enlargement and the creation of a “glide path”, that is a pathway with smooth canal walls along which the NiTi instruments can easily slip and slide to reach the working length.

It has frequently been reported that manual pre-flaring is very important to reduce the incidence of breakage. For example, the study by Berutti et al.32 evaluated the influence of manual pre-flaring and torque on the incidence of breakage of ProTaper instruments. The study used 400 plastic blocks, divided in two groups. All the simulators were shaped with the ProTaper files, but in one group the use of rotary instruments was preceded by manual pre-flaring up to a K File # 20. The result showed that after preflaring the ProTaper instruments were able to shape a markedly larger number of simulators before breaking (Fig. 1).32

The new GT SERIES X rotary shaping system

The new GT SERIES X rotary shaping system


Redesigning a standard for worldwide appeal

The GT rotary shaping system was introduced to the US market in 1996 and to the rest of the world 18 months afterwards , and while it took the US by storm, it met with more resistance internationally – due to the differences in the dentist’s populations, competitive environments, and the way the product was delivered to the end user.

As I approached the redesign and development of what would become the first true ‘next generation’ of this product line, I took the broader needs of those performing root canal treatments everywhere into consideration. After two years, the GT Series X (GTX) endodontic system was introduced at the Annual Meeting of the American Dental Association in October 2007 and is scheduled for worldwide distribution in the spring of 2008.

When dentists were polled, they universally said that what they want from their shaping files were, in this order:

  1. Resistance to breakage
  2. Fidelity to the original canal path
  3. Cutting efficiency.

A second list of requirements in international market and increasingly in the US and Canada, were, in this order:

  1. A reduced file set
  2. Less crown-down shaping
  3. A simplified method of cutting initial shapes in root canals
  4. A shaping method requiring fewer files to accomplish an ideal preparation.

Ironically, the difficult challenges of delivering the universal requirements were rewarded serendipitously in delivering the more specific needs of the international market.

First off, I was gratified to note that the first 2 are both related to safety, as it should be.

However, as simple as the concept of safety seems, the multivariate and often oppositional functional characteristics of file geometry make for a serious analytical challenge.
Examples of these countervailing features are abundant.

While larger core diameters enhance a file’s resistance to torsional stresses in straight canals, they radically increase their susceptibility to cyclic fatigue in curved canals.

While sharper cutting flutes decrease friction and the resultant torsional stresses accumulated in a file during cutting, they significantly increase the amount of transportation from the original canal path in curved canals.

Beyond the difficulties of understanding factors that come to bear in safety objectives, it is no less obscure to determine how these geometric variants affect efficiency. Do we look only at the cutting efficiency of a file blade during the use of a single file in a single cutting cycle, or do we consider the number of instruments and steps necessary to complete the root canal preparation? Do we compare files relative to how long they can cut in an apical direction before their flute spaces are jammed with debris?

Tetraclean: A contribution to root canal cleaning

Tetraclean: A contribution to root canal cleaning




Dr. Luciano Giardino



The aim of endodontic therapy is to remove the infection and root out the bacteria from the root canal system (Sjogren U, Fidgor D, Persson S, Sundqvist G. Influence of infection at the time of root filling on the outcome of endodontic treatment of teeth with periapical periodontitits Int. End. J 1997; 30(5): 297-306).

The instrumentation is unable to root out the bacterial load by itself (Bystrom A, Sundqvist G. Bacteriologic evaluation of the efficacy of mechanical root canal instrumentation in endodontic therapy. Scan J Dent Res 1981; 89(4): 321-8).

These findings have been confirmed by subsequent works, as well, such as Dalton et Al.’s (Dalton BC et Al. bacterial reduction with nickel-titanium rotary instrumentation. J Endod 1998; 24(11): 763-7), which pointed out that there is no noticeable difference in root canal cleaning when rotary or manual instruments are used.

During the instrumentation phase the main function of the irrigants is to remove the debris from the root canal: thanks to the synergy between instrumentation and irrigation the number of bacteria inside the root canal is significantly reduced (Siqueira JF, et al. Mechanical reduction of the bacterial population in the root canal by three instrumentation techniques. J Endod 1999; 25(5): 332-5).

As Radcliffe pointed out (Radcliffe CE et Al: Antimicrobial activity of varying concentrations of sodium hypochlorite on the endodontic microrganisms Actinomices Israelii, A. naeslundii Candida Albicans and Enterococcus Faecalis Int. Endod. J 2004; 37: 438-46) the action of sodium hypochlorite is made difficult by the anatomical complexity of the endodontium (pic 1), by the polymicrobial nature of the bacterial flora (pic 2), by the presence of the biofilm (pic 3) and by the presence of the smear layer (pic 4) produced by our instruments.

Nickel Titanium (Ni-Ti) Endowave Morita instruments

Nickel Titanium (Ni-Ti) Endowave Morita instruments










It is undeniable and generally accepted that the success in endodontic therapy, aside from the performance of a correct access cavity aiming at removing coronal interferences, is linked to the synergistic action of three fundamental stages: the correct shaping, the cleaning-sterilization of the endodontic space and its hermetic and stable filling.

In the age of Nickel-Titanium we have to face almost every day new instruments coming out on the market that should make it possible for the operator to perform a faster and safer work and new equipment that should make the root canal filling simple, fast and predictable.

The aim of this work is to propose a new technique which, while respecting the aforementioned triad shaping-cleaning-filling, allows not only the specialist in endodontics but also the “general practitioner” to perform a fast, safe, predictable and extremely ergonomic root canal therapy.

Gutta-percha nowadays is still the most widely used root canal filling material: it is used in various ways, e.g. the warm compressing technique, the use of carriers, the low temperature side filling, the mechanical compressing, the use of expensive equipment to heat up and/or for the backfilling.

nichel titanium instruments

All these procedures need a long learning curve if they are to be put correctly in operation.

The “Schilderian” warm compression itself on the one hand provides wonderful radiological images when performed correctly, on the other requires such a sacrifice of dentinal structure, needed to bring the warm spreader to at least 4 mm from the apex, that can endanger the structural integrity of the treated element.