The purpose of this work was to study the effects of the Nd:YAG laser on exposed dentinal
tubules of human extracted teeth using a scanning electron microscope (SEM). Eighty 2.5mm-thick
slices were cut at the cementoenamel junction from 20 extracted human teeth with an electric saw. A
diamond bur was used to remove the cementum layer to expose the dentinal tubules. Each slice was
sectioned into four equal quadrants and the specimens were randomly divided into four groups (A to D ).
Groups B to D were lased for 2 mins using an Nd:YAG laser at 6 pulses per second at energy outputs of
80 , 100 and 120 mJ. Group A served as control. Under SEM observation, nonlased specimens showed
numerous exposed dentinal tubules. SEM observation revealed that application of Nd:YAG laser at
energy output of 80 mJ may cause melting of dentin and partial closure of exposed dentinal tubules
without dentin surface cracking. But when the energy output raised to 100 and 120 mJ more sealing of
dentinal tubules occurs. Heat generation occurred in all lased groups but the amount of temperature
increase was within the permissible limits(less than 5.5⁰C). The measured sealing depths were from 3-
5μm for groups B-D and the width of the created groove was 30μm in all lased groups. In conclusion
lasing with nanosecond Nd:YAG with a wavelength of 1064nm at 120mJ with 6Hz for 2 minutes (group
D) shows the efficient laser parameters for complete sealing of exposed dentinal tubules without
temperature increase to the damaging level of the pulp tissue.
Abstract
The human mind knew the philosophy and logic in the ancient times, and the history afterwards, while the semiotics concept appeared in the modern time, and became a new knowledge field like the other knowledge fields. It deals, in its different concepts and references, with the processes that lead to and reveals the meaning through what is hidden in addition to what is disclosed. It is the result of human activity in its pragmatic and cognitive dimensions together. The semiotic token concept became a knowledge key to access all the study, research, and investigation fields, due to its ability of description, explanation, and dismantling. The paper is divided into two sections preceded by a the
... Show MoreThe chamomile is one of the most important medicinal plants recommended for treatment of asthma and some respiratory system diseases. This research was designed to research the effects of aqueous extract of chamomillarecutita on histological structure of Diaphragm of albino mice. The study included 40 male albino mice Musmusculus, their age ranged from (5-7) weeks.The mices were divided randomly to 5 groups and oral administered with 1 ml every day for 10 days:- First Group G1: consider as control group and treated with normal saline,Second Group G2: was treated with aqueous extract of chamomile with concentration of 3 gm /100 ml D.W, Third Group G3: was treated with aqueous extract of chamomile with concentration of 5 gm /100 ml D.W.Fourth
... Show MoreIn subterranean coal seam gas (CSG) reservoirs, massive amounts of small-sized coal fines are released during the production and development stages, especially during hydraulic fracturing stimulation. These coal fines inevitably cause mechanical pump failure and permeability damage due to aggregation and subsequent pore-throat blockage. This aggregation behavior is thus of key importance in CSG production and needs to be minimized. Consequently, such coal fines dispersions need to be stabilized, which can be achieved by the formulation of improved fracturing fluids. Here, we thus systematically investigated the effectiveness of two additives (ethanol, 0.5 wt % and SDBS, 0.001 and 0.01 wt %) on dispersion stability for a wide range of condit
... Show MoreThe degradation performance of aqueous solution of pesticide Alachlor has been studied at solar pilot scale plant in two photocatalytic systems: homogeneous photocatalysis by photo-Fenton and heterogeneous photocatalysis with titanium dioxide. The pilot scale system included of compound parabolic collectors specially designed for solar photocatalytic applications, and installed at University of Baghdad, Department of Environmental Engineering back yard. The influence of different concentrations, H2O2 (200-2400 mg/l), Fe+2(5- 30 mg/l) and TiO2 (100-500 mg/l) and their relationship with the degradation efficiency were studied.
The COD removal efficienc
... Show MoreThe social tolerance is one of the important variables in personality; it helps growth and development of individual's personality. Theories and the students affirmed that social Tolerance affects the society growth and development as well.
The presents study aims:
1. Estimating the social Tolerance for Baghdad College students.
2. Realizing how College students vary in social Tolerance according to:
Sex, (Male, Female) ٍSpecialization (Scientific, Humanity).
3. Realizing the nature of relationship between social Tolerance of College students and father and mother styles. To achieve this research goals the researcher established parameter (scale) for social Tolerance applied to sample of (500) students male and female. Th
This research aims to know the reality of implementation of Knowledge Management in Saudi Universities Applied in Shaqra University and to study the difficults whish encountered in applying the Knowledge Management approach.
The study investigated the university staff in Shaqra, Thadig, and Huraymila branches, using a questionnaire designed by the researcher to collect the data, sample of (260) members was used, applying the descriptive analytical approach to test the hypothesis by using (SPSS) program.
The study revealed that the first four zero hypothesis are rejected because there is medium approval of the university members on the fo
... Show MoreThe researcher wanted to make an attempt to identify the foundations of social solidarity, to strengthen the bonds of brotherhood among society, and spread the causes of compassion in the hearts of its members.
The researcher has taken a short course in the hearts of the beloved to hearts.
The Objective of the research is to identify the Strategic Vigilance and effect in the Managerial Decision Quality, by knowing the interest of the organization influence the Strategic Vigilance in the Managerial Decision Quality, adopted four dimensions of the Strategic Vigilance is (Environmental Vigilance, Commercial, Competitiveness & Technology) to indicate the extent individually and collectively impact in the Managerial Decision Quality, The questionnaire was used as a main tool to survey the views of a sample of 45 managers, was named Supreme Judicial Council society for research, and the statistical program SPSS, and research found a clear positive impact dimensions Strategic Vigilance in the Manageri
... Show MoreThe research discusses the most important goals and means of IGAD in making peace in Sudan and then regional peace.
ABSTRACT
Impkact of Knowledge sharing on organizational innovation Impriscal study in Arabic company .
of Knowledge Management is the main component Knowledge sharing system, it mean the exchange if Knowledge, ideas, and good practice with another individual . Knowledge sharing between persons, then its values can growth .
It is vry important because it can provide us with the contention between virus peoples . the interaction among the people can pass all kind of Knowledge among them. the connection and interaction and interaction enabl
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