الفهرس 
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Abstract
The aim of this study was to evaluate in vitro the
effectiveness of two different apex locators (Root ZX II and Csmart
I) in detecting simulated horizontal and vertical root
fractures of different thickness and different location.
A total of 60 extracted teeth were inspected for the absence
of cracks, perforations, fractures or any defects. Teeth were
decoronated at the cementoenamel junction and adjusted to 15
mm in length. Samples were classified into two main groups, one
for simulated HRFs (40 teeth) and the other for the VRFs (20
teeth). The first group with HRFs was subdivided into two
subgroups according to the location of fracture, coronal (5 mm
away from the coronal surface) and apical (10 mm away from the
coronal surface). Then each subgroup was further subdivided into
two subdivisions according to the size of fracture, 0.15 mm and
0.20 mm (10 teeth each). The second group was subdivided into
two subgroups according to the size of fracture, 0.15 mm and 0.20
mm (10 teeth each). Five teeth were used as control without any
further preparation.
Each root was fixed in a copper mould using acrylic resin.
Moulds were then held against the disk to simulate HRF and
VRFs using copious amount of water coolant until the canal got
exposed. The simulated VRF was started with the disk touching
the root surface at 7.5 mm from the coronal surface.
To verify canal exposure, sterile saline was injected in each
canal and saline leakage from the simulated fracture site was
examined visually with the help of cotton pellets.
To confirm the actual vertical fracture level for group II
with VRFs, small K-file #8 or #10 was then introduced through
the cut perpendicular to the long axis of the root. A digital
radiograph was then taken and the software used to calculate the
actual fracture level.
Resinous cast (model) was used to fix the teeth. Alginate
impression material was mixed and poured into it and roots were
immersed in it before setting.
One lip clip was immersed in the alginate before setting and
the file holder attached to K-file# 15. This K-file# 15 attached to
the file holder was then introduced into each root canal until the
meter reaches the mark ”apex” on the screen of each EAL and the
beeping sound heard; the stopper was set on the flat surface of the
root (reference level) and the distance measured.
Measurements were obtained immediately after setting of
the alginate impression material. All samples were measured first
using Root ZX II apex locator and then measured by using the Csmart
I apex locator.
A percentage was calculated for each reading using the
following equation:
(Apex locator reading x 100)/Actual fracture level.
The difference in measurement was calculated as the
absolute difference between the apex locator reading and the
actual fracture level measurement. Data were collected and
statistically analyzed.
Results:
Root ZX II readings were shorter than the actual fracture
level with a statistically significant difference for the simulated 0.20
mm apical HRF (I2b). No statistically significant difference was
shown between the other three subdivisions with simulated HRF
and the actual fracture level using Root ZX II.
No statistically significant difference was shown between
different fracture thickness, 0.15 mm and 0.20 mm (subdivisions I1a
and I1b) and (subdivisions I2a and I2b) coronally or apically using
Root ZX II.
There was a statistically significant difference in detection
of 0.15 mm and 0.20 mm HRFs coronally and apically
(subdivisions I1a and I2a; I1b and I2b) using Root ZX II.
There was no statistically significant difference between the
mean of the C-Smart I readings and the actual fracture level for all
subdivisions of group I with simulated HRFs (I1a, I1b, I2a, I2b).
Also no statistically significant difference was shown in detection
of simulated HRFs using the C-Smart I for different simulated
fracture thickness within the same level (subdivisions I1a versus I1b
coronally and subdivisions I2a versus I2b apically).
There was no statistically significant difference shown in
detection of simulated HRFs using the C-Smart I for the same
thickness fractures at different levels (subdivisions I1a versus I2a
0.15 mm and subdivisions I1b versus I2b 0.20 mm).
There was no statistically significant difference between the
mean of the Root ZX II reading and that of the C-Smart I for
subdivisions I1a, I1b, I2a and I2b with simulated HRFs.
There was no statistically significant difference between the
mean reading and the actual fracture level for both subgroups with
simulated VRFs (Iia and Iib) using both apex locators. No
statistically significant difference was shown in detection of
simulated VRFs of different thickness (subgroups Iia and Iib) using
both apex locators.
There was no statistically significant difference between the
mean of the Root ZX II reading and that of the C-Smart I for both
subgroup with simulated VRFs.
There was a statistically significant difference between the
mean percentage value of accuracy of the Root ZX II readings for
group I (HRFs) and group II (VRFs). There was a statistically
significant difference between the mean percentage value of
accuracy of the C-Smart I readings for group I (HRFs) and group
II (VRFs).