الفهرس 
coverOnly 14 pages are availabe for public view
 |  | from | 106 |  |  |
| | | from | 106 | | |
Abstract
This in vitro study was designed to investigate the effect of ozonated
gel as a dentin conditioner on the shear bond strength of resin composite to
different dentin substrates. A total of 200 sound, human molars were used .
Out of the 200 molars 20 were used as a control and 160 were used for shear
bond strength testing and for SEM examination. Teeth were divided into two
groups, of 80 teeth each, according to the depth of tested dentin either
superficial or deep ones. The groups were subdivided into two subgroups of
40 teeth each according to the type of the smear layer pretreatment either
with or without EDTA. The subgroups were further divided into two classes
of 20 teeth each according to the concentration of ozone dose either 120
µg/ml at 1 ml
3
/seconds or 190 µg/ml at 1 ml
3
/seconds. Finally, each class
was subdivided into two subclasses of ten teeth each according to
application time of ozonoted gel either 10 or 15 seconds. The control teeth
were treated with acid etching. They were divided into two groups of ten
teeth each according to dentin depth also. Twenty teeth were conditioned
with silica based gel and used for SEM examination.
A specially constructed split Teflon mold was used, and filled with
self- cure acrylic resin and the tooth was embedded in the centre. Teeth were
cut at 0.5 mm below the dentino-enamel junction to obtain the superficial
dentin specimens. For deep dentin specimens teeth were cut at 1.5 mm
below the dentino-enamel junction. A specially designed copper holder was
fabricated to hold the acrylic blocks. The ozone gas was generated by the
Ozomax unit. A glycerin based gel was used to prepare an ozonoted gel.
Another ozonated gel was prepared using silica gel. Conditioning of dentin
surfaces was done either with EDTA, ozonoted gel or the acid etch. The
EDTA was applied for 3 seconds while the ozonated gel was applied for
either 10 or 15 seconds and the acid etch was applied for 15 seconds.
Washing and air drying was done, then two consecutive coats of the
adhesive were applied and cured for 10 seconds. Each specimen was then
placed inside the copper holder and the split Teflon ring was placed within
its created room. The hybrid composite was packed inside the Teflon ring
and a celluloid matrix strip was placed over the ring and curing was done for
40 seconds with a light curing unit.