Impact of Apical Patency on Accuracy of Electronic Apex Locators: In Vitro Study.

INTRODUCTION: This study aimed to investigate the importance of apical patency and its influence on the accuracy of 2 apex locators (Root ZX and Raypex 6). METHODS: We determined the actual working length under dental operating microscope at ×25 magnification in 43 extracted human mandibular molars with completely formed roots and patent apical foramen. Readings of the 2 apex locators were then compared with the actual microscopic working length. Thereafter, we established apical blockage at the apical foramen; files were introduced to the same previous length determined by each apex locator before blockage. Variation in the readings of apex locators after blockage was compared with original readings before blockage to determine the measurement error. RESULTS: Friedman's test showed no statistically significant difference between the 2 apex locators before blockage (P > .05; effect size = 0.013). Within the margin of accuracy ±1, both Root ZX and Raypex 6 revealed the same percentage of accuracy, 96.7%. After blockage, both apex locators revealed a statistically significant difference in median measurement error compared with the measurements before blockage (P < .05; effect size = 0.305). Root ZX showed a higher median measurement error (>-1 mm and 0.01-0.5 mm) than Raypex 6. CONCLUSIONS: Apical foramen blockage has a negative influence on the accuracy of apex locators that was more pronounced in Root ZX than Raypex 6.

Cryotherapy: A New Paradigm of Treatment in Endodontics.

INTRODUCTION: The aim of this review article was to discuss the concept of cryotherapy, its mechanism, physiological effect, and its different applications in the field of endodontics. METHODS: The selected articles were limited to those published in the English language using the following key words: cryotherapy, cryogenic treatment of nickel-titanium, cold therapy, and cryotherapy in endodontics. The screening of articles was based on an electronic search of the following databases: PubMed, Scopus, Web of Science, and Egyptian Knowledge Bank. RESULTS: The initial search yielded 98 citations, 78 of which were included. On the basis of the collected data, 32 studies addressed the physiological effect of cryotherapy, 10 focused on illustrating a different application of cryotherapy during root canal treatment, and 36 were concerned with the effect of cryogenic treatment on endodontic instruments. CONCLUSIONS: It can be concluded that cryotherapy is a simple and cheap supplementary method for minimizing postoperative pain in cases of symptomatic apical periodontitis and for controlling pulpal hemorrhage during vital pulp therapy. Undoubtedly, it is also an indispensable measure for controlling postsurgical swelling and pain after endodontic surgery. However, further studies are needed to clarify the effect of cryogenic treatment of the recent generations of nickel-titanium rotary instruments.