Chumpon Luangaram. The influence of a local anesthetic containing vasoconstrictor on microtensile bond strengths of two adhesive systems to human dentin in vivo . Master's Degree(Operative Dentistry). Mahidol University. : Mahidol University, 2004.
The influence of a local anesthetic containing vasoconstrictor on microtensile bond strengths of two adhesive systems to human dentin in vivo
Abstract:
Theoretically, performing adhesive techniques in vivo, dentinal fluid has
detrimental effects on adhesive systems. In this study, the experiment was set up to
prove this assumption. A clinical study was performed on upper premolars scheduled
for extraction for orthodontic reasons. The experiment was divided into two parts. In
part 1, the bond strength test, 47 premolars were prepared on occlusal surfaces in a
condition with or without a local anesthetic containing vasoconstrictor prior to cavity
preparations, bonded with either Single Bond or Clearfil SE Bond and filled with a
resin composite, Filtek Z250. The teeth were then extracted and prepared for the
microtensile bond strength test. In part 2, observation of dentin surface, 20 premolars
were assigned into 2 groups. In group 1, the teeth were anesthetized with a local
anesthetic containing vasoconstrictor before cavity preparation. The prepared dentin
was then treated with or without acid etching and impressions were taken with a
polyvinyl siloxane impression material. In group 2, as a control group, the teeth were
treated in exactly the same procedures as those in group 1 but no local anesthetic was
administered. The results in part 1 demonstrated that the conditions with or without a
local anesthetic containing vasoconstrictor had no effect on the bond strengths of both
adhesive systems (p>0.05). In part 2, in the etched group with a local anesthetics
containing vasoconstrictor, the results revealed 3 different patterns but the surface of
the coalescent dentinal fluid from the tubules was observed in most specimens. On the
other hand, fluid covering dentin surface was visible in all replicas in the group using
acid etching without a local anesthetic. Granular appearance of smear layer was found
in both unetched groups but the granules were slightly larger in the group without a
local anesthetic containing vasoconstrictor. This study found that a minute amount of
dentinal fluid flow in vivo did not have detrimental effects on both adhesive systems