‘‘EVALUATION OF THE ACCURACY OF NEW GENERATION APEX LOCATORS- DENTAPORT ZX AND IPEX- AN IN VITRO STUDY.’’
Brief resume of intended work : 6.1 Need for study :
The determination of accurate working length is a critical step in an endodontic therapy. Establishing the working length at the apical constriction is considered ideal for endodontic treatment, because obturation should terminate at the minor diameter of the root canal.1 Radiographic location of the minor diameter is not predictable because of its limitations. Electronic apex locators are more accurate and predictable in detecting minor diameter of the root canal.
In the present endodontic scenario electronic apex locators are extensively used to determine the working length. Introduction of the newer electronic apex locators put the practisioner under the dilemma to choose the better one. Hence it is essential to compare the efficiency and accuracy of the recently introduced electronic apex locators.
In the present in vitro study, we will be comparing the accuracy of newly introduced apex locators- Dentaport ZX (J.Morita,Japan) and iPex (NSK,Japan) .
6.2 Review of Literature :
Ounsi HF., Naamam A. (1999) evaluated the reliability of the Root ZX electronic apex locator and experimental comparision was made of the Root ZX apex locator with the real measurement of the root canal length in which saline gel was used to stimulate the periodontium. Length were taken when the needle reached the 0.5 mark and the Apex mark on the meter. These measurement were then compared with a calculated reference length representing the real length of the root canal. They found that Root ZX was not capable of detecting the ‘0.5 mm from the foramen’ hence, should be only used to detect the major foramen.2
Kaufman AY., Keila S., Yoshpe M. (2002) conducted this study on 120 extracted teeth embedded in alginate medium to test in an in vitro model the accuracy of a Bingo 1020 electronic apex locators, to compare the results to those of a well known apex locators, Root ZX, as well as to those of the radiographic method of tooth length measurement. The teeth were randomly divided into 12 groups of 10 each. They found that Bingo 1020 proved to be as reliable as Root ZX and was user friendly and under the experimental conditions, electronic measurements were more reliable than radiographs in the process of root length determination.3 Tselnik M., Baumgartner JC, Marshall JG. (2005) performed this study to compare the accuracy of the Root ZX and Elements Diagnostic electronic apex locators under clinical conditions. The mean distances from the file tip to the minor diameter were 0.346 mm for the Elements Diagnostic and 0.410 mm for the Root ZX beyond the minor constriction. They found that there was no statistically significant difference between the accuracy of the two electronic apex locators in locating the minor diameter.4
D’Assuncao, de albquerque DS, de Queiroz Ferreria LC. (2006) compared the ability of the Root ZX and Novapex electronic apex locators (EALs) in locating the apical foramen on40 extracted teeth. The actual length (AL) and electronic length (EL) measurements were made on each specimen separately with both devices with an aid of a K-file. The results obtained with each EAL were compared with the corresponding control length. They found that that the Root-ZX and Novapex are usefull and accurate devices for the apical foramen location.5 Guise GM., Goodell GG., Imamura GM. (2010) conducted an in vitro study and compared the accuracy of Root ZX II Apex locator (RZX), Elements Apex locators (ELE) and Precision Apex locators (PAL) on 40 extracted single rooted teeth mounted in gelatin conducting medium and randomly tested with each apex locators to determine the electronic canal length.Difference between the electronic and actual canal length were calculated. They found that RZX was the most accurate at locating the apical foramina compared with the ELE and the PAL.6
6.3 Objectives of the study:
The objectives of this in vitro study are as follows:
To evaluate the accuracy of Dentaport ZX (J.Morita,Japan).
To evaluate the accuracy of iPex (NSK,Japan).
To compare the accuracy of Dentaport ZX (J.Morita,Japan) and iPex (NSK,Japan).
Methodology 7.1 Source of data:
The study will be conducted in the Department of Conservative Dentistry and Endodontics, MMNGH Institute of Dental Sciences and Research Centre, on forty extracted single rooted human teeth.
7.2 Methods of collection of data:
Forty extracted single rooted with single canaled human permanent premolars with patent root canals and fully developed root apices will be selected for the study.
Teeth having resorbed roots, cervical caries, root caries, cracks in roots, immature apices, fractured roots and severe root curvature will not be included in the study.
1. Materials and Methodology: This study involves 40 extracted single rooted non-carious permanent premolars that have been indicated for orthodontic extraction. After removal of the extraneous tissue and calculus teeth will be placed in 2.5% sodium hypochlorite solutions for 2 hours for surface disinfection and preserved in 0.2% chlorhexidine solution until use. Radiovisiographic images will be taken in both bucco-lingual and mesio-distal directions/planes to confirm the presence of single root canal. Then teeth will be decoronated with a diamond disc to standardize the root length to 12mm. The coronal one-third portion of each canal will be preflared using Gates Glidden drill (Mani Inc,Japan) to provide unrestricted access to the root canal. Then pulp extirpation will be done with a barbed broach following copious irrigation with normal saline.
Teeth will be randomly numbered from 1 to 40. Working length of each sample will be determined by Dentaport ZX (Group 1) and iPex (Group 2) in the alginate medium as per the manufacturer instructions, using separate 10 no.K-file for each sample.
After determining the working length stoppers of all the files will be stabilized by light cure composite.
Once the working length of all the samples are determined with both the apex locators, Saggital sectioning of all the samples will be done with the diamond disc. Corresponding file is repositioned in the sectioned sample and photograph of minor diameter will be taken under stereomicroscope.
The distance between file tip and minor diameter will be measured under stereomicroscope and values are interpreted as positive (beyond minor diameter) or negative (short of minor diameter) depending upon the location of file tip in respect to minor diameter. The exact working length is determined from the minor diameter to reference point of each sample separately using 10 no.
K-file under stereomicroscope. The values obtained will be converted into millimetres by using standardized formula provided by manufacturer as:
No of units = values in millimetres.