Ex vivo accuracy of three electronic apex locators using different apical file sizes

• Published in: Brazilian dental journal 2012, Vol.23 (3), p.199-204
• Main Authors: Vasconcelos, Bruno Carvalho de, Matos, Leonardo de Alencar, Pinheiro-Júnior, Elilton Cavalcante, Menezes, Antônio Sérgio Teixeira de, Vivacqua-Gomes, Nilton
• Format: Article
• Language: English
• ISSN: 0103-6440; 0103-6440
• DOI: 10.1590/S0103-64402012000300003

This study evaluated the accuracy of three electronic apex locators (Root ZX, Novapex, and Justy II) in root canal length determinations using different apical file sizes, considering the apical constriction (AC) and the major foramen (MF) as anatomic references. The diameter of the apical foramina of 40 single-rooted teeth was determined by direct visual measurement and the master apical file was established. Electronic measurements were then performed using 3 instruments: the selected master apical file (adjusted file), one size smaller (intermediate file), and two sizes smaller (misfit file). The distances from the tip of files fixed in the canals to the MF and to the AC were measured digitally. Precision at AC and at MF for the misfit, intermediate and adjusted apical files was as follows: 80%/88%/83% and 78%/83%/95% (Root ZX); 80%/85%/80% and 68%/73%/73% (Novapex); and 78%/80%/78% and 65%/78%/70% (Justy II). Considering the mean discrepancies, statistically significant differences were found only for the adjusted file at MF, with Root ZX presenting the best results at MF. The chi-square test showed significant differences between the acceptable measurements at AC and at MF for the Justy II and Novapex (± 0.5 mm) regardless of file adjustment. Under the conditions of the present study, all devices provided acceptable electronic measurements regardless of file adjustment, except for Root ZX which had its performance improved significantly when the precisely fit apical file was used. Justy II and Novapex provided electronic measurements nearest to the AC. Este estudo avaliou a precisão de três localizadores eletrônicos foraminais (Root ZX, Novapex e Justy II) nas determinações de odontometria utilizando limas com diferentes padrões de ajuste, considerando-se a constrição apical (CA) e do forame principal (FA) como referências anatômicas. O diâmetro dos forames apicais de 40 dentes unirradiculados foi previamente determinado por visualização direta e a lima compatível com o forame apical foi estabelecida. Medições eletrônicas foram realizadas utilizando 3 instrumentos diferentes: lima compatível com o forame apical (lima ajustada), lima um tamanho menor (lima intermediária), e lima dois tamanhos menores (lima desajustada). As distâncias da ponta dos instrumentos ao FA e a CA foram determinadas em software específico. A precisão na CA e no FA para os instrumentos desajustado, intermediário e ajustado foram: 80% / 88% / 83% e 78% / 83% / 95% (Root ZX); 80%