Aim of the study: To study the effectiveness of using dental operating microscope
and ultrasonics with Hedstrom files in removing gutta-percha and sealer from root canals.
Materials and Methods: Twenty single straight rooted, extracted human mandib
ular
premolars were prepared, filled with gutta-percha and sealer (Zinc oxide with eugenol).
Specimens were then divided into two groups (N1=N2=10), and root filling material was
removed using H-files with Eucalyptol (group 1); H-files with Eucalyptol, followed by
using microscope with ultrasonic tip (group 2). After retreatment, the efficacy of each
technique was examined at 8× magnification with a stereomicroscope then the images were
analyzed using Auto-CAD 2010 according to Hulsmann and Stotz scale.
Data were statistically analyzed using Mann–Whitney U-tests.
The use of Nickel-Titanium rotary instruments have been increasing in the last two
decades. But the probability of fracture is still the most important hindrance that confuse
the practitioners. And many clinicians claim that the removal process is
very difficult and
often irretrievable. When compared with stainless steel instruments, hence this study aims
to compare between the two types effect of endodontic instruments on the success of
microsonic technique in removing or bypassing it, and the degree of difficulty.
Laser use and applications in dentistry has increased dramatically in the last
years. Laser etching of enamel may provide an alternative for conventional acid etching. The aim of this
study was to evaluate, under Scanning Electron Microscope(SEM),
enamel surface morphology after
laser irradiation with or without the addition of photoabsorber (black ink); with or without acid etching.
laser enamel etching produced surface
roughness that might be used for the infiltration and subsequent mechanical retention of resin.
This research is the first descriptive and classifiable study of the Syrian
spores of mosses in Syria and Arab world by using the technique of scanning
electron microscope.
Samples have been collected from several areas from Syria and their names
have been defined and classified earlier.
The study of nine Spieces of Spores have been completed and their shapes,
different faces and the shapes of redundant which they carry and their
distribution by scanning electron Microscope are done in Jena University,
Germany. Their sizes have been measured and viewed in several sizes.
It has been noticed clear differences in Spores, in the Shape of concavity of
the frost face and in existence and relation of denseness and distribution of
redundant on the faces. So, The characters of Spores can be added to other
standards which are used in Classification of mosses.
There are wide uses of tin oxide thin films, especially in the field of
transparent conductors, solar cells, gas sensors and piezoelectric materials.
Laser deposition is considered one of the most important techniques followed to
obtain these film
s. In this research, we develop a technique to obtain
homogeneous thin films of tin oxide depending on vaporization of pile targets of
this oxide by continuous CO2 laser in the atmosphere, with a fan which
guarantees obtaining homogenous films. Some of these films were annealed in
different conditions. The optical microscope images revealed the presence of
high degree of homogeneity, while the X-Ray study showed different
crystallization grain orientations which depend on the preparation conditions.
The preferred direction is (110). The optical absorption gives information
about the value of the effective band gal for the samples before and after
thermal annealing. We have found that some films have Eg = 3.2 ev. before
annealing, and after long annealing they have Eg=1.3ev. In addition, the hard
annealed thin films reveal anisotropy in the optical and electrical.
Characteristics, they have different absorption coefficients in two
perpendicular directions, also there is an electrical resistance anisotropy along
these two directions especially after hard annealing. The Eb was 0.73 ev before
annealing, it became 0.37 ev for one direction and 0.32 ev for the other
direction.
