Problem-Solving Challenges in Root Canal Obturation

Root Canal treatment

Introduction

Laser ablation (LA) therapy is used as an adjunct to root canal treatment to improve microbial reduction. However, studies evaluating the impact of LA with indocyanine green (ICG) are scarce. This study aimed to evaluate the antimicrobial efficacy of LA therapy with ICG in root canal treatment.

 Welcome to this section, which serves as a repository for medications that are relevant to the treatment of Root Canal Treatment in Dubai. The page includes both generic and brand names and can be an invaluable resource for healthcare professionals and individuals who wish to get an insight into different medication options.

Root canal sealer or cement

A root canal sealer or cement is essential with any gutta-percha technique, just as an etching agent and bonding material are required when using resin-filling techniques. These products serve many functions, such as being a lubricant to facilitate obturation and adhesiveness to enhance the seal and stability of the root canal filling. When mixed properly, they can be elevated from a mixing slab approximately 1 inch (2.54 cm) and held there for 5 to 10 seconds without flowing off the elevating instrument. The sealer will flow into the dentinal tubules if the smear layer has been removed, depending on the obturation technique used, and may be expressed through lateral or accessory canals.

Ideally, all sealers should be antimicrobial and biocompatible; some sealers or portions of substances within them may be absorbed when exposed to tissues and fluids. Substances used for radiopacity within the sealer are generally insoluble and may remain in the tissues either engulfed by macrophages or surrounded by fibrous capsules. If large amounts are pushed beyond the canal confines, the patient may experience discomfort, especially if the sealer has a slow set or chronic inflammation may persist and create problems at a later time. Sealers may be consolidated during the healing process and remain pushed up against the root of the tooth by the encapsulating tissue, never really allowing the tissue to heal fully, although clinicians attempt to identify this as healing so long as the patient is symptom-free.

Sealers are generally grouped based on their primary component or chemical makeup (e.g., polyketone, epoxy, calcium hydroxide, silicone, glass ionomer, or resin-based). Ideally, none of these sealers should be extruded beyond the end of the root canal, because chronic inflammation may persist. However, many clinicians attempt to extrude the sealer with their obturation technique and empirically claim that when they see sealer extruded beyond the confines of the canal, the canal is “perfectly sealed. The fallacies in this position are that a seal cannot be seen on a radiograph, the radiograph only represents two dimensions of a highly variable three-dimensional object, and there is no evidence-based information to support this claim. As noted earlier, there is evidence to support the long-term presence of chronic inflammation.

Non-surgical root-canal treatment

The ideal root-filling material

Concepts of the ideal root-filling material are changing as the role of obturation is better appreciated. The root-filling material of the past was inert but it is more conceived as a bioactive material now. The required properties of an ideal root-filling material have been defined as follows:

o it should induce or at least support the regeneration of damaged tissues

o be antimicrobial

Do not irritate periradicular tissues

o not be toxic either locally or systemically

to be easily adapted to the canal walls and have the capacity for self-adaptation and self-sealing with dimensional fluctuations over time

o have good flow characteristics

Do not stain dentine

o have good handling characteristics

o be radiopaque

o be impermeable to tissue fluids

to be dimensionally stable

to be cheap and have a long shelf-life

Historically, a plethora of materials has been used to obturate the root canal system. Effective use requires an understanding of the properties of the material and an appreciation of the anatomy and morphology of the root-canal system. Many obturating techniques and materials were designed and used based on misunderstandings of this morphology.

Solid cores

Solid obturators, such as silver, titanium, or acrylic cones were designed to fit snugly into a canal “machined” to an equivalent dimension. However, the irregular nature of the root canal system was not fully accounted for and these solid cores fitted only where they touched the irregular canal walls. The remaining spaces were filled with cement or sealer. Over time, tissue fluids could percolate into the canal system as the sealer is gradually washed out. In cases obturated with silver cones, this was deemed to induce corrosion products (silver sulfites and chlorides) , which were thought to provoke an apical inflammatory response.

Pastes

Many “paste” materials have been formulated to “simplify” obturation and have been recommended for use alone or in combination with a master cone. As it is not possible to compact a paste, it is virtually impossible to ensure complete obturation of the root canal system with paste materials unless they expand on the setting. Expanding materials though may be difficult to confine to the root-canal system. Extrusion of obturation materials beyond the confines of the root canal system is undesirable and, in the case of some paste materials, can result in permanent damage to adjacent structures, such as neural tissue.

Gutta-percha

The most commonly used obturating material has been gutta-percha (trans-polyisoprene) (Fig. 8.190). It has been used in endodontics in Dubai as the core filling material for well over 100 years. The gutta-percha used in dentistry is composed of approximately 19–22% of trans-polyisoprene and 59–75% zinc oxide filler with other additives (Table 8.3). The additives include waxes or resins, which enhance the plasticity of the material, and metal salts, which are used to increase the radiodensity of the material. The exact composition of the commercially available product varies from manufacturer to manufacturer.

The stereo-chemical formula of gutta-percha is the mirror image of natural rubber (a transisomer of rubber) and exists in three different forms; two crystalline forms (α and β) and an amorphous form. All three forms play a part in root canal obturation. Gutta-percha harvested from the Palaquium gutta tree is mainly the α-phase while that in gutta-percha cones available commercially exists mainly as the β-phase. The β-phase is converted to the α-phase by heating to 42–49°C. Further heating to between 53°C and 59°C results in the loss of the crystalline form and the formation of an amorphous melt (Fig. 8.191). The relevance of these structural changes is that they are associated with volumetric changes that in turn influence the clinical procedures during obturation. Manufacturers of some thermoplasticized obturating systems, such as Thermafil® stress the importance of maintaining vertical compaction pressures on the molten gutta-percha in the coronal portion of the canal system while the material cools and undergoes contraction and shrinkage. This vertical pressure is necessary to compensate for the volumetric contraction associated with the cooling of the gutta-percha in the root canal system.

Commercially available dental gutta-percha demonstrates several of the properties of the ideal root-filling material but does not fulfill all of the properties by any means. It is not toxic and is cheap. It is possible to encourage flow by thermoplasticizing it and it adapts fairly well to the canal wall but does not bond to dentine. It does not stain dentine; it is radiopaque (due to added radiopaque agents) has good handling characteristics and has a relatively long shelf-life. Clinically, it is not very irritating to periradicular tissues but histologically provokes a chronic inflammatory response, particularly in smaller particulate forms. In addition, it neither induces nor supports regeneration of damaged tissues. Despite its many drawbacks, it remains the material of choice of those commercially available. The following discussion on obturation techniques relates to the use of gutta-percha as the obturation material.

Alternative materials

Resilon®

This relatively new material exhibits the properties of gutta-percha and looks like it. It is composed of the polymer polycaprolactone. It is used with an adhesive sealant, “epiphany” in an attempt to create what has been described as a “monoblock”, however, the existence and survival of such a physical entity is not proven. It exhibits similar thermoplastic and chemical properties to gutta-percha and is therefore relatively inert.

Experimental materialsThe trend is towards the development of bioactive root-filling materials that may aid in killing residual bacteria, create an ongoing seal despite disruption in an aqueous environment through precipitation of salts, and facilitate regeneration of apical tissues through release of growth factors. Figure 8.192 shows an example of an experimental material that forms a precipitate at the interface in an aqueous environment that enables a seal without a conventional sealer that is better than conventional gutta-percha and sealer (Alani et al., 2009).

SealersA root-canal sealer is a radiopaque luting agent used, usually in combination with solid or semisolid core material, to fill voids and seal root canals during obturation. All current obturation techniques require the use of a sealer to fill minor discrepancies and voids in the obturation and to improve the seal between the core material and the walls of the canal. Sealers also act as a lubricant during gutta-percha placement and reduce leakage.

Sealers can be divided into several main groups based on their constituents:

o zinc-oxide/eugenol materials (Roths, Pulp canal sealer, Wachs, Tubliseal, Procosol)

o calcium hydroxide-containing materials (Sealapex, Apexit, CRCS)

o  glass ionomer (Ketac-Endo)

o resins (Diaket, Lee Endo-Fill)

o flexible polymers (Epiphany)

o bioceramic (Smartpaste).

As with all obturating materials, the ideal sealer should be biocompatible, adhere to canal walls, be radiopaque, impermeable to tissue fluids, be dimensionally stable, antiseptic, not discolor the tooth, and be easily manipulated.

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Root canal treatment