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Thanks to its flexibility, the IrriFlex needle by Swiss company Produits Dentaires (PD) allows simple and efficient access to the apical areas of curved roots. (Image: PD)

IrriFlex—endodontic irrigation needle for better results

By PD (Produits Dentaires SA)
May 29, 2020

VEVEY, Switzerland: Root canal preparation is an essential step in endodontic treatment and aimed at removing the current content of the root canal and preparing it for filling. The objective is to prevent the onset or recurrence of apical periodontitis. The use of rotary instruments with continuous rotation has made treatments faster, more comfortable and more predictable over the past 20 years. Many developments in instrumentation have helped improve preparation systems. But despite all these advances, the complexity of root canal systems results in unprepared or unpreparable areas that require the complementary use of chemicals for cleaning.

The market is full of irrigation systems designed to further enhance this step. Many studies have been carried out to find the perfect irrigation solution, one that meet all the criteria in terms of both efficiency and biocompatibility. Unfortunately, there simply is no such solution at this point. Sodium hypochlorite remains the gold standard of antiseptic solutions, while EDTA and citric acid remain the gold standard among chelating agents, required at the end of the preparation process. However, IrriFlex, a needle recently developed by Produits Dentaires has provided a new choice of irrigation needle.

Irrigation in endodontics

Irrigation is an essential part of endodontic treatment. It is irrigation that allows antiseptic preparation of a root canal. Irrigation is therefore required from the time of accessing the pulp chamber until the restorative material is introduced into the root canal.

The anatomies of root canal systems are highly variable and can be very complex, so it will usually be impossible to mechanically prepare the entire system. However, it is still imperative to clean the entire root canal system to achieve effective cleaning and to perform a successful endodontic treatment. For this reason, irrigation is a mandatory complement to the preparation of canals with rotary instruments, which, while reducing the bacterial count in instrumented areas by up to 90%, have no effect in areas that are not and cannot be instrumented.

A needle and a syringe

Various irrigation systems are currently in use. Root canal irrigation with a syringe and a needle is still the most common procedure today. Syringes are generally classified according to the design of their tips. Luer tips (which are not necessarily Luer lock tips) are conical, with a 6% taper. Luer lock tips feature the same conical design, but also provide a locking mechanism for the needle that prevents it from accidentally sliding off the syringe. All needles have some form of connector with which to attach them to the syringe. The length and thickness of the needle can vary greatly, depending on the procedure to be performed. Its diameter is measured in gauge numbers, which range from eight to 30, corresponding to 4.57 mm and 0.31 mm, respectively. The higher the gauge number, the slimmer the needle. It is quite possible to encounter two needles with the same lengths but different diameters.

Closed-ended needles for improved efficiency

The needle can end in a bevel and can feature one or several lateral openings. Being familiar with these different needles is particularly relevant in endodontics. It has been demonstrated that closed-ended needles must be used to prevent irrigation solution entering the periapical space. The pertinent studies were based on visualising and examining the trajectories of particles of the irrigation solution at the root canal level.

IrriFlex is a slightly conical 30-gauge needle made of plastic and possesses two lateral vents arranged back to back just short of its closed end. This unique device facilitates an efficient lateral flow and reflux of the solution while controlling the extrusion risk. In effect, this means that the needle must never become stuck in the root canal (thus the preparation must be sufficient at all points) and that the liquid is ejected slowly and at low pressure, 1–2 mm from the working length. The lateral flow is conducive to the cleaning of isthmuses and root canal irregularities.

Figs. 1a–c: (a) Radiograph and superimposed photograph of a mandibular molar showing the insertion of a metallic 27-gauge Endoneedle and an IrriFlex needle. Scanning electron microscope image of (b) a clean root canal wall and a root canal wall covered with dentine slurry and pulp debris (c).

A promising alternative

A comparative scanning electron microscope study on debris removal showed that the IrriFlex needle and syringe system was more effective than the conventional Endoneedle (Elsodent) and syringe system. The IrriFlex needle displays interesting properties during root canal irrigation. This might be explained by its flexible nature that allows it to penetrate the root canal network more easily without breaking, but also by the presence of several lateral openings at the same level, which balances the pressure and flow of the expelled irrigant. These openings ensure extra-broad exposure of the entire root canal.

Endodontic treatment requires root canal preparation instruments that work in synergy with an irrigation solution. The complexity of root canal systems prevents sufficient cleaning by mechanical preparation alone, mandating the additional use of chemical agents. The IrriFlex needle appears to be a promising device, showing superior results to the traditional needle and syringe method. It is flexible and has a very small diameter, which allows simple and efficient access to the apical areas of curved roots.

Editorial note: This text is an edited extract from a clinical article written by Dr Franck Diemer that originally appeared in roots international, issue 1/2019.

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