Reports & Studies

Efficient and atraumatic root canal treatment

Long-term conservation of dentition is the prime objective of modern endodontics.

Alongside efficient diagnostics and treatment methods, the use of the latest technical aids and instruments also makes an important contribution to successful patient care. Dr Shahrad Nouraie Ashtiani and his team at the practice in Bremen, Germany, treat up to ten endodontics cases a week. Patients’ desires for treatment which is as atraumatic as possible combined with good prognoses for success present a daily challenge for the dentist and oral surgery resident specializing in endodontics.

As an avid user of the expanded W&H instrument range for ultrasonic endodontics, Dr Nouraie Ashtiani is not only able to perform root canal treatments more efficiently but also to do so in a way which puts less strain on the patient. The dental expert masters even the most difficult of situations with ease. In a recent interview, the specialist in endodontics told us about the particular features which characterize the W&H instruments and mentioned possible risks which can arise in root canal treatment.

Does the expanded endo tip range have all the necessary applications covered for your endodontic indications?

Dr. Nouraie: Yes, in my opinion. The tips allow you to work in a particularly atraumatic and minimally invasive manner. Among other steps, this applies to the exposure of the individual canal accesses, preparation of the cavity in the area of the pulp chamber, rounding off of the canal openings at the transition from the bottom of the chamber to the root canal and preparation of the coronal regions of the root canals.

orthograde endodontic instruments
With the six orthograde endodontic instruments W&H offers dentists a practical selection for endodontic treatments.

It is also possible to activate the rinsing fluid in the root canal system. What’s more, it makes a range of special indications such as the revision of broken-off instruments and root posts possible.

The range is complemented perfectly by a tip for lateral condensation.

Could you describe the use of the most important tips for you and name a couple of clinical advantages?

Dr. Nouraie: I particularly enjoy working with the 1E tip. It is perfectly suited to activating the rinsing fluid in the root canal system. The delicate design of the tip allows you to reach deep sections of the canal too and ensure optimal activation.

Thanks to the material reinforcement at the transition from the working end to the shaft, the risk of this thin instrument breaking has now been minimized.

1E tip
The 1E tip follows the curved course of the canals and is an indispensable aid for all root canal treatments.

The 2E tip is used for lateral condensation. In this filling technique, the master points in the canal are adapted first and then the gutta-percha condensed laterally via the insertion of the instrument, with the result that additional space is created for further tips. The next tip is introduced into the canal and condensed (compacted) again. This procedure is repeated until the canal is filled.

Alternatively, for a root filling revision – where permitted by the canal anatomy and advance preparation – the instrument can be introduced into the canal and used to soften the gutta-percha minimally via the heat generated by the activation, rendering removal in the coronal section simpler.

The 3E tip was specially designed for the removal of broken-off and fractured root canal instruments. In my experience, this is possible from the coronal section down to the central canal section with corresponding magnification (min. 3.6x dental loupes, ideally microscope).

This step should be performed with a non-diamond-coated, sharply tapered tip, with which it is possible to expose the fractured fragments of the instrument in the dentine region under microscopic control. In addition, the instrument is perfectly suited to exposing broken-off root canal posts coronally so that they can subsequently be shaken out with the 5E tip.

3E tip
The fine, diamond-coated 3E tip is optimally suited to the exposure of fractured root canal instruments among other indications.

I also use this tip a lot to clear dentine overhangs away from thin canals and make the canal openings clearly visible. It is particularly well suited to applications in the second mesiobuccal canal on the maxillary molars or in cases of obturated canals. In the case of thin canals, the function is almost identical to that of the 6E tip, which works optimally in medium-sized to wide canals.

4E tip
Atraumatic preparation of the cavity floor with the 4E tip.

The 4E tip – this instrument is optimally suited to preparation of the cavity floor at the transition to the canals. It can be used to round off the transition between the canal and the cavity floor optimally so as to produce a funnel leading into the canal. In addition, the instrument is the ideal choice for removing dentine overhangs from canals.

All in all, the cavity can be prepared very efficiently and minimally invasively with this tip by optimally rounding off and smoothing overhangs, corners and edges.

The 5E tip was designed specifically for shaking out and removing fractured root canal posts by vibration. The pieces should always be exposed in advance, as this facilitates the procedure considerably.

The 6E tip was designed for removing old root fill materials from the canal openings, exposing the canal openings and removing calcifications from the canal openings.

This is the main focus of this instrument, which is ideal with this tip, although the slightly larger diameter means it is better suited to canals with a medium-sized or wider scope. For thin canals, the 3E tip is a better choice. Both instruments can also be used to prepare the coronal sections. NB: Formation of steps. When used for this purpose, it is essential to ensure that no steps are created in the canal.

Do you have a favourite tip?

Dr. Nouraie: I have various favourite tips, but my absolute favourite tip and the one I couldn’t be without is the 1E tip. It really is useful in every single root canal treatment, as it can be used to activate the rinsing fluid. It is well known that, alongside the preparation, rinsing of the root canal is the most important component of the treatment. Activated rinsing fluid penetrates deeper into the dentinal tubules, thereby achieving better results. As such, activation of the rinsing fluid plays an important role in improving the quality of this type of treatment.

The 6E/3E and 4E tips are also some of my absolute favourites, but the indications for those are somewhat more strictly delineated. They are not necessarily always required for broad canals with one root, but are almost always used for teeth with multiple canals. Possible applications include removal of dentine overhangs from cavities, perfect rounding off of transitions and making thin canals and openings visible. However, caution should be exercised, as steps may be formed.

What advantages do the W&H ultrasonic tips bring with them for the treatment result in your eyes?

Dr. Nouraie: The use of ultrasonic tips allows targeted, atraumatic, minimal removal of substance at the desired site (e.g., when exposing the canal openings, rounding off the cavity floor and exposing broken-off instruments or posts as well as when processing coronal canal sections).

Canal transitions can be smoothed and rounded off with more precision than when using burs. The activation of the rinsing fluid in particular offers enormous advantages that cannot be guaranteed with other instruments. The special instruments from W&H make it possible to perform completely new indications minimally invasively such as revision of broken-off tips and posts.

Visual aids such as dental loupes or even better a surgical microscope should be employed for all indications in the canal. In addition, I also think it is important that all the applications in the canal – with the exception of the activation of the rinsing fluid – are performed by specialized colleagues with corresponding experience and the necessary expertise in the field.

The risk of perforations and steps forming in the canal must not be underestimated, as the risk increases the deeper one delves into the canal.

dental loupes or a surgical microscope
In combination with a state-of-the-art ultrasound system, visual aids such as dental loupes and surgical microscopes are essential tools for successful endodontic treatment.

How satisfied are you with the service life of the endo tips? How do you rate the abrasion performance of the two 4E and 6E tips?

Dr. Nouraie: I am very happy with both the abrasion performance and service life of the tips. If I had to change anything, I would make the round head of the 4E tip even rounder. To date, I have not had any tip break when I was using it and I have not noticed any deterioration in the abrasion performance, even after frequent use. The two 3E and 6E tips in particular, which feature a second angulation, facilitate work in the posterior molar region of patients with small mouth openings considerably.

Would you recommend the W&H endo tip range to your colleagues? Which tips are particularly worth recommending in your opinion?

Dr. Nouraie: For me, ultrasonic endodontics is an optimal complement to the techniques previously available. Use of the expanded W&H endo tip range makes it possible to improve the quality of the treatment and thus the long-term prognosis for the teeth substantially. The quality of the tips is exceptionally high and absolutely worth recommending.

I find the abrasion performance particularly impressive, as it remains constant even after frequent use. In addition, the instruments can also be reprocessed very simply and cost-effectively.

Dr. Shahrad Nouraie Ashtiani
Dr. Shahrad Nouraie Ashtiani

Thank you for that enlightening discussion!

Pictures: Dr. Shahrad Nouraie Ashtiani, Bremen