An Initial Research On Aging Transform Of The Anatomical Structure Of Apex

ObjectivesThe aim of this study was to observe the anatomical structure, to measure the distance from apical constriction to anatomical apical foramen and anatomical apical, and to analyze the relationship between the distance of apex and age, either to evaluate the relationship between the accuracy of working length determination by EAL and age with the help of stereomicroscope.Methods1.144 extracted human teeth were examined and grouped according to age by human epidemiological criteria. Under stereoscope the distance of the anatomical structure of apex and the relationship between the distance and age were measured after making tooth ground-section.2.83 root canals were tested in vitro Electronic canal length (LE) measurements were recorded with EAL respectively at the reading "Apex" and "0.5". Under stereoscope the deviation of LE from the actual working length and degree of accuracy were determined. To analyze the relationship between the accuracy of working length determination and age.Results1. The distance between apical constriction and anatomical apical foramen and the distance from apical constriction to anatomical apical have significant difference in three groups(.P<0.05).The distance increases with age.2. The accuracy of the measurement was 91.49%in the aged, and 88.89%for those in the middle-aged, the difference between them was not statistically significant (P>0.05). Age had no effect on the accuracy of working length determination of anterior tooth by EAL.3. The average deviation of the measurements obtained by EAL at the reading "Apex" was lower than zero and that obtained by EAL at the reading "0.5" was higher than zero, the difference between the absolute value for those was not statistically significant (P<0.05).Conclusion1. The distance of the anatomical structure of apex increases with age.2. In the vitro, the accuracy of the measurement by Root ZX in the aged and for those in the middle-aged, the difference between them was not statistically significant. EAL can measure the working length accurately at the reading "Apex" in every age group.