الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 96 |  |  |
| | | from | 96 | | |
Abstract
The aim of this study was to compare the difference between integrated endo motors and the non-integrated endo motors with Root ZX-II electronic apex locator for maintenance of working length throughout the preparation of the canals. A total Sixty human lower molars with mature fully formed apices were selected according to the selection criteria previously mentioned from the out-patient clinic of the Oral and maxillofacial Surgery Department, Faculty of Dentistry, Alexandria University. Access cavities were performed using rose head carbide bur and deroofing of pulp chamber using endo-z bur. Flattening of mesio buccal cusp was done to get a fixed reference point. The Apical Foramen standardization and visual measurements was performed by introducing file #10 K-file till the tip become visible at the most coronal border of the apical foramen opening. The mixed alginate was poured in ice blocks and the teeth were embedded inside the alginate before it set. Saline solution was used to keep the alginate model moistened throughout the experiment by using. The teeth were randomly divided into two groups according to type of motor used for the preparation of the root canal. For both groups after preparation with the rotary files (G file and two shape file system) a #25 k file with 2 percent taper was inserted in position using the last recorded working length (2WA) and cemented in place using dual cure glass ionomer cement or flowable composite and light cured for 1 min. The length was rechecked with electronic apex locator to confirm the file was cemented to the full working length. The specimens were randomly coded with numbers to provide blinding, shaving was done longitudinally for the apical 4 mm using a diamond bur until the file was visualized in the canal space and then the sections were examined under a stereomicroscope to evaluate violation of the minor constriction. The distance had a positive value if the file tip was found apical to the minor
66
constriction zone, negative value if the file tip was found incisal to minor constriction zone, and zero value if the file tip is present inside minor constriction zone. The mean distance from the minor constriction to file tip was calculated. Data were analyzed. Results showed that positive values (overextensions) were observed in 90% of the cases for MM Control and 53.3% of the cases for Root ZX-II. The former results suggest that the MM Control device is not reliable for the EAL function using the APEX mark.