Abstract
In root canal therapy, the method of root canal obturation is selected based on the morphology of the prepared root canal. The single point obturation technique involves filling the root canal space using a single gutta-percha point in a canal that has been enlarged and shaped by reaming. However, the fit between the root canal morphology after preparation and the gutta-percha point is often poor, making it difficult to achieve a tight seal. Therefore, a root canal obturation technique that tightly fills the canal using lateral or vertical condensation of the gutta-percha point is necessary. Stainless steel files (abbreviated as SS files) are used in curved canals by applying a pre-curve, but they are prone to causing transportation at the apical potion. On the other hand, NiTi rotary files (abbreviated as NiTi files) possess superelasticity and can prevent transportation due to their excellent adaptability to curved canals; however, they have a tendency to fracture, leading to ongoing improvements over the years. Since NiTi files are used with rotational motion, the cross-section of the canal becomes circular after preparation, and the morphology matches that of the final working file. Consequently, tapered products such as 4%, 6%, and confit guttapercha point were developed, establishing a root canal filling system with high adaptability to root canal morphology. Furthermore, new materials for root canal sealer (abbreviated as RC sealer) have been developed, featuring properties such as adhesion, bonding, biocompatibility, and expansion. As a result, the single-point root canal filling method was established, which uses a newly developed RC sealer with a single gutta-percha point that fits the circular root canal formed by NiTi files. This article provides an overview of standard root canal treatment using ISO international standard instruments and the singlepoint root canal filling method, which has achieved innovative advancements.
