Influence of maintaining apical patency in post-endodontic pain

The Complexity of the Root Canal Anatomy and Its Influence on Root Canal Debridement in the Apical Region: A Review

The main goal of root canal treatment is to eliminate the infection in the complex root canal system for the long-term preservation of a functional tooth. Proper debridement of the root canal system, especially in the apical portion, is essential for successful root canal treatment. The complexity of the canal anatomy in the apical region plays a crucial role in reducing the microbial load. Therefore, clinicians must have a thorough knowledge of the anatomy of the root canal system and its variations, especially in the apical portion. Root canal configurations in cross-section have been classified as round, oval, long oval, flattened, or irregularly shaped. Treating oval, long oval, flattened, or irregularly shaped canals is challenging and should be approached differently than a circular canal. Recognizing the root canal shape and apical anatomy determines the different strategies to be used in cleaning, shaping, and obturation to achieve the best result of root canal treatment. The recent development of the instrumentation system improves the treatment outcome for clinicians and patients. This review aimed to discuss the definition, prevalence, and instrumentation for cleaning and shaping in the apical area with the complexity of root canal systems. Therefore, with the aid of this review, we can better understand the variations in the anatomy of the root canal, especially at the apical portion.

The Effect of Patency Files on Apical Canal Anatomy Using SEM Imaging

Introduction

There are many reasons to maintain apical patency during routine endodontic treatment. Thousands of canals are treated utilizing a patency file every year all around the world. The effect patency has on the apical anatomy of the root has been controversial for generations.

Objective

This ex vivo descriptive study was created to show the effect patency files actually have on the apical root canal anatomy using visually detailed SEM images supported by dental radiographs.

Materials and Methods

Three extracted maxillary anterior teeth that represent the multitude of canals in vivo were instrumented utilizing patency files. Two of the three maxillary anterior teeth were instrumented with hand files, the other maxillary anterior tooth with a .06 taper rotary file. The teeth were then scanned with an electron microscope to view the effect that the instruments had on the apical canal anatomy. A fourth tooth, a maxillary second molar, was shaped with an .06 taper rotary file and cone fitted. This tooth was radiographed with a gutta percha cone fitted to reveal the position of the narrowest constriction after patency was achieved.

Results

The patency files, both hand files and rotary, were shown not to adversely affect the apical canal anatomy. Additionally, the SEM's revealed a precise demarcation of cementum to dentin which was at the root surface after patency was achieved.

Conclusion

The patent use of greater tapered rotary files provides a clear demarcation of the CDJ which allows a precise acquisition of the narrowest constriction of the canal with the use of an electronic apex locator for establishing the ideal working length and precision placement of a gutta percha cone.

Impact of Radial Lands on the Reduction of Torque/Force Generation of a Heat-Treated Nickel-Titanium Rotary Instrument

This study investigated the impact of a one-sided radial-landed cross-sectional design of a heat-treated nickel-titanium rotary instrument (JIZAI, MANI, Japan; JZ) on torque/force generation and canal-shaping ability, using an experimental non-landed instrument (non-landed JZ) for comparison. Both instruments had tip sizes of 25 and 0.04 or 0.06 taper and were similar in metallurgy and geometry, except for the presence/absence of a radial land. Twenty J-shaped simulated resin canals were instrumented in a two-instrument single-length sequence using an automated root canal instrumentation device with a torque/force analyzing unit. Pre- and post-instrumentation images of the resin canals were analyzed for canal-centering ability at 0–3 mm from the apex. The mean centering ratio was not significantly different between JZ and non-landed JZ (p > 0.05). In the 2nd instrumentation, JZ showed a significantly smaller torque compared with the non-landed JZ (p < 0.05). Regardless of instrumentation sequence, JZ showed a significantly smaller maximum upward force, representing screw-in force (p < 0.05), and a larger maximum downward force (p < 0.05) than the non-landed JZ. JZ generated smaller screw-in forces and had similar canal-centering ability compared with the non-landed JZ.