Today, more than ever before, the world has become a small cosmopolitan village as
a result of the information, communication and communication revolution that humanity is
witnessing under a globalized capitalist system that has turned itself into
passive
peripheries and active centers.
In the context of the existing global capitalist polarization, peripheral countries suffer
from double backwardness; they are both technologically and structurally backward. Thus,
find themselves faced with the challenge of this complex backwardness, both in the field of
productive forces and in the field of relations of production.
The challenge of underdevelopment, in the first field, requires engagement in world
system centers through capitalist market mechanisms, prevalent there and at the global
level. In addition, the challenge of backwardness, in the second field, requires
disengagement with these centers in order to build new non-capitalist relations of
production, as a structural condition necessary to ensure the development of productive
forces with local resources and competences. This will soon lead to the disconnection of
dependency linkages, and thus national control over the engagement itself. Hence, the
engagement is a necessary element for disengagement, which does not mean autarchic, in
any case.
As a result, logically and objectively, the dialectics of engagement and
disengagement are connected organically to the dialectics of market and planning, in a way
that is related to the need of developing the productive forces and building the productive
relations with a different essence.
This study aimed to test the efficiency of debonding porcelain laminate veneers
(PLV) by using two application modes of Er:YAG laser (contact and non-contact mode),
and testing the change in dental pulp temperature for both application modes.
Sixt
een extracted, non-carious human maxillary premolars, prepared for receiving
PLV, which fabricated of e.max and bonded by light cured resin cement. They divided into
two groups, each of them had 8 samples based on the application mode; group A with noncontact
mode, and group B with contact mode. Veneers of both groups debonded by the
same laser parameters (360mJ, 15Hz) during loading of a 20newton force on a specially
fabricated cervical margin of veneers. Debonding time and change of temperature was
recorded, then entered into SPSS V.19 and T-test for independent samples was applied.
All veneers were debonded, samples of non-contact mode group had much lower
debonding time (12.6 second) than contact mode samples (96.3 second), but with higher
change of temperature in non-contact (4.2 centigrade) than in contact mode (2.9
centigrade).p value was much less than 0.05%.
Within limits of this study, we can conclude that non-contact application mode was
more efficient in reducing debonding time than contact application mode at same laser
energy and frequency parameters, but with a higher change in pulp temperature.
