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Accuracy of working length measurement: electronic apex locator versus cone‐beam computed tomography
Author(s) -
Lucena C.,
López J. M.,
Martín J. A.,
Robles V.,
GonzálezRodríguez M. P.
Publication year - 2014
Publication title -
international endodontic journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.988
H-Index - 119
eISSN - 1365-2591
pISSN - 0143-2885
DOI - 10.1111/iej.12140
Subject(s) - apex (geometry) , cone beam computed tomography , nuclear medicine , mathematics , constriction , apical constriction , computed tomography , materials science , orthodontics , medicine , geometry , surgery , chemistry , biochemistry , morphogenesis , gene , endocrinology
Aim To compare the accuracy of working length ( WL ) determination using the R aypex 6 ® electronic apex locator and cone‐beam computed tomography ( CBCT ). Methodology A total of 150 extracted human teeth were decoronated and randomly assigned to five groups ( n = 30). WL was measured with the R aypex 6 ® at both the ‘constriction’ and the ‘apex’ marks under dry conditions (group 1) or with 2.5% Na OC l, distilled water or U ltracain ® (groups 2–4). The radiological WL (group 5) was calculated from bucco‐lingual and mesio‐distal CBCT sections. Differences between electronic, CBCT measurements and actual length ( AL ) were calculated. Positive and negative values, respectively, indicate measurements falling short or long of AL . Two‐way anova and the B onferroni and W elch tests were used to compare mean differences amongst groups. The chi‐squared and Fisher's exact tests were used to compare percentages of precise, ±0.5 and ±1.0 mm of the AL measurements amongst the experimental groups. Statistical analysis was performed at α = 0.05. Results Mean differences with respect to AL ranged from 0.26 to −0.36 mm and from 0.05 to 0.18 mm, respectively, for the electronic measurements at the ‘constriction’ mark and ‘apex’ mark. CBCT measurements were an average of 0.59 mm shorter than AL . Percentages of electronic measurements falling within ±0.5 mm of the corresponding AL referred to the ‘apex’ mark were greater than at the ‘constriction’ mark, but the differences were only significant in group 4 (with U ltracain ® ). Percentages of CBCT measurements falling within ±0.5 mm of AL (46.7%) were significantly lower than electronic measurements, regardless of the condition of the root canal. In 30–38.5% of the measurements taken at the ‘apex’ mark and in 3.4–13.3% of those at the ‘constriction’ mark, the file tip extended beyond the foramen. Conclusions Electronic measurements were more reliable than CBCT scans for WL determination. The R aypex 6 ® was more accurate in locating the major foramen than the apical constriction under the experimental set‐up.