In vivo Study to Evaluate the Effect of Instrument Size on the Accuracy of Three Different Apex Locators when Various Irrigation Solutions are used in Vital and Non-Vital Teeth.

INTRODUCTION: Root canal success requires working length (WL) optimization. The current study examined how different apex locators on vital and non-vital teeth responded to instrument size.

MATERIALS AND METHODS: Three hundred patients (180 men and 120 women) receiving root canal therapy at the department of Conservative Dentistry and Endodontics were evaluated. Therefore, we determined that 200 of the patients' teeth (100 vital and 100 non-vital teeth from the upper and lower jaws' first molars) qualified for inclusion in our study. The pulp chamber was accessed using a sterile round bur. The coronal region of the root canal was preflared with successive Gates Glidden drills (Mani Inc. Japan) and irrigated with any one of the solutions 3% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), or 17% ethylenediaminetetraacetic acid (EDTA) solution after checking canal patency with a size #10 K file, where (#-number). Later, the working length was established using Ingle's technique and a radiovisiograph (RVG) 0.5 mm short of the radiographic apex. Two endodontists approved this RVG.

RESULTS: Overall, the #15 K file and apex locators did not differ from Ingle's method. While the #8 K file differs significantly from all apex locators, the #10 K file showed a significant difference with all apex locators except Root ZX with 2% CHX ( P = 0.06). Irrigation didn't influence apex locators' accuracy.

CONCLUSION: Even in the presence of irrigating solutions, electronic apex locator (EAL) can be utilized to calculate the working length with accuracy. The apex locators #15 k files, #10 k files, and #8 k files showed the most promising results.