|Year : 2022 | Volume
| Issue : 2 | Page : 73-75
Revisiting the future of root canal obturation
James L Gutmann1, Vivian Manjarrés2, Catalina Méndez De La Espriella2
1 Department of Endodontics, Texas AM University College of Dentistry, Dallas, Texas, USA
2 Department of Endodontics, Nova Southeastern University College of Dental Medicine, Ft. Lauderdale, Florida, USA
|Date of Submission||25-May-2022|
|Date of Decision||30-May-2022|
|Date of Acceptance||02-Jun-2022|
|Date of Web Publication||01-Jul-2022|
Dr. James L Gutmann
Texas AM University College of Dentistry, Dallas, Texas
Source of Support: None, Conflict of Interest: None
The techniques for root canal obturation have undergone several changes in the last 10 years. While warm vertical compaction had been the major method of filling the canal, which included the use of core carriers made of structurally stable gutta-percha, recent developments in the manufacturing of precision-tapered, gutta-percha cones and the use of bioceramic root canal sealers have become the clinician's choice in the past few years. The impact of these revolutionary changes is explored with open ended questions and challenges for the reader.
Keywords: Bioceramic root canal sealers, Core-carrier gutta-percha, Precision fitting master cones
|How to cite this article:|
Gutmann JL, Manjarrés V, De La Espriella CM. Revisiting the future of root canal obturation. Endodontology 2022;34:73-5
| Introduction|| |
The history of root canal obturation using various materials and techniques has been reported by many authors., Some approaches to this clinical challenge were questionable, while others worked at least initially. For decades, dentistry and endodontics have focused on developing a highly predictable method to achieve that elusive, three-dimensional filling, which was once termed the “hermetic seal,”, along with the long-term retention of the tooth in symptom-free function. To date, while some contemporary studies extol the virtues of various approaches to achieve this goal, achievements are still far from perfect, as technical achievements in the process are now being scrutinized by μCT in laboratory studies and cone-beam computed tomography in clinical performance.,
A little over 10 years ago, a paper was published that addressed the future of root canal obturation. The message that was proffered indicated that the best way to achieve this goal was to use an age-old material, gutta-percha that had been revolutionized in its properties and applications through advances in material science and polymer chemistry. In fact, the technique advocated was, at that time, the most recent iteration in a long list of proclaimed ideal approaches to root canal obturation that included lateral compaction, warm vertical compaction, continuous-wave condensation, centered condensation of warm gutta-percha, injectable thermoplasticized systems and metallic and plastic core-carrier placed thermoplasticized systems. The essence of this revolutionized obturation system consisted of the development of strong core material that was made from a cross-linked, thermoset elastomer of gutta-percha known as GuttaCore. The core, when coated with alpha phase gutta-percha, allowed clinicians to achieve their desired goal of a three-dimensional adaptation of softened filling material into the highly irregular anatomical features of the root canal system. While many obturation techniques rely on lateral or vertical compaction techniques, the hydraulic forces from these techniques sent gutta-percha in one or two unequal and unpredictable directions (laterally or apically). With GuttaCore, however, the vectors of force for the movement of softened gutta-percha during placement were in all directions within the canal. When the root canal system was properly enlarged, shaped, cleaned, and disinfected, the resulting space permitted a maximization of the hydraulic force and flow of gutta-percha and root canal sealer into the canal irregularities.
At the time of this innovative process, standard root canal cement/sealers were advocated and consisted of numerous products that ranged from the traditional zinc oxide-eugenol-based formulations to resin-based materials, along with several personalized clinician choices., While Grossman highlighted the key elements required of a sealer,, the clinician most probably focused on the degree of radiopacity and flow that would enable the appearance of the final root canal filling to appear as a densely filled and void-free obturation with a satisfying appearance of filled accessory anatomy and what was termed by the clinician, as a well-sealed canal due to the presence of “puff” of the chosen sealer appearing apically and laterally. This appraisal has been the standard only too often used in social media aggrandizements. Unfortunately, neither clinical criterion nor expectations addressed the biological basis of periapical tissue response or healing in the presence of this extruded material. Attention to this latter concept was emerging in stature in the form of bioceramically based root canal sealers.,
Ceramics, and in particular calcium silicates and aluminates, have been used in medical and dental devices for years due to a wide range of their in vitro and in vivo properties. In their cement form, the key attribute to these materials focuses on their ability to induce biomineralization, in which the material forms a layer of hydroxyapatite on its surface in vivo. This property is ideal for pulpal preservation (a key concept that today is more appropriately used as opposed to vital pulp therapy) in the form of pulp capping and pulpotomy and obtaining a hard tissue response coronally, or for that matter the attainment of a cemental seal apically, when used in nonsurgical root canal procedures or as a root-end filling material in periapical surgery.
The evolution of these products, while often thought of as being the introduction of mineral trioxide aggregate in the early 1990s,, stems from the original product, Portland cement, that was patented in 1824 by Joseph Aspdin (1778–1855), who was a bricklayer in Leeds, England. The name “Portland” was chosen because of the resemblance of the cement to the oolitic limestone of Portland, England. The limestone was used extensively in England as a road metal and building stone. The use of this material in the filling of the root canal appears to be documented first by Witte in 1878, with a subsequent focus on Witte's technique by Schlenker in 1880.
Multiple technological advances have intersected and become incorporated into contemporary advocated techniques of canal obturation over and above the use of the core-carrier technique. The outcome of this intermingling has been further influenced by the focus on minimally invasive, advocated root canal procedures, including coronal access preparations and the use of more predictable canal shaping with heat-treated, flexible nickel–titanium instruments, newly advocated irrigation protocols, and laser-cut gutta-percha cones that provide precision fitting and adaptation to the apical third of the shaped canal. Coupled with advances in bioceramic/bioaggregate technology based on the original Portland cement of Aspdin, this decade of enhanced root canal procedures has reached an all-time high and many more teeth are being retained. However, along with these achievements, comes clinician accountability and favourable outcomes, for which there is minimal long-term, meaningful data. In many respects, data of this nature are highly dependent on more than just the application of these technological advances in root canal procedures. The true outcome of success is at the mercy of the following considerations:
- Anatomical variations and complexities
- Eradication of the bacterial species and biofilms from the highly irregular root canal anatomy
- Performance of each procedure at the highest level
- Clinician expertise and variability
- Clinician assessment/cognitive dissonance
- Restoration of the root-treated tooth/occlusal function
- Absence of periodontal disease
- Absence of tooth defects–undiagnosed fractures/resorption
- Response of the periradicular environment to the use of these new materials in the form of biological healing
- Long-term integrity of the new root canal sealers and their resistance to possible solubility in the periradicular environment.
With these perspectives in mind, what then is the future of root canal obturation when the contemporary advocacy of minimal canal preparation, single-cone obturation, often without any compaction beyond the coronal third of the canal, and the use of the bioceramic root canal sealers appears to be the modus operandi of most practicing endodontists and general dentists who chose to retain teeth? Can this approach to obturation ensure the filling of all canal irregularities, especially in the apical one-third? Do we have long-term, evidenced-based outcomes globally to support this approach? Is this the new paradigm for root canal obturation? Are we to be totally reliant on the root canal sealer for success? True gutta-percha has been with us for 175 years and has been enhanced as the major core material with improved properties, such as adaptation to the shaped canal only, along with newer physical characteristics. The trends in clinical practice, however, focus on more of a reliance on the bioceramic root canal sealers and abandonment of compaction techniques, except for GuttaCore, which serves to compact the material in the canal as discussed previously. Ironically, the future of obturation may be bright, but only time will tell; however, unless there can be enhancements in the irrigation and disinfection protocols, with a cognizant application by the clinician using proper techniques and solutions, all the other aspects of the procedures will not provide, by themselves, predictable successful outcomes. Furthermore, the potential of the dissolution/solubility of the bioceramic sealers has also been identified as a significant concern.,
Presently, it is not the obturation that is the future of root canal success but the elimination of the causative agents, such as bacteria and biofilms that will determine tooth retention. The specialty of endodontics is currently challenged to pursue research efforts to enhance this process. Progress is being made in this realm with the use of nanoparticles, energized fluid technology,, and the use of microrobotics.,,
However, even these achievements alone will also be challenged if the root-treated tooth is not properly restored, occlusal discrepancies eliminated, and periodontal disease prevented or managed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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