Abstract:
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In oral orthodontic treatments, achievement of
a good adhesion between brackets and teeth surfaces is
essential. One way to increase adhesion is to apply a surface
treatment of teeth facing surfaces through the projection
of abrasive particles to produce a surface roughness
which improves adhesion of the bracket to the tooth,
because of the significantly increased contact between the
two surfaces. The effect on adhesion through the use of this
technique in different types of brackets, as well as through
the use of different blasting particles, however, is yet not
well described. In this study we have included three types
of brackets which are commonly used in orthodontic
therapies (two of them a mesh-type and the third one a
micro-milled type) with a contact surface area of 11.16,
8.85 and 6.89 mm2 respectively. These brackets were used
combined with a sandblasting treatment with two different
types of abrasive particles, alumina (Al2O3) and silicon
carbide (SiC) and applied to natural teeth in vitro. The
abrasive particles used are bio-compatible and usually used
in achieving increased roughness for improved adherence
in biomedical materials. Sandblasting was performed at 2
bars for 2 s; three particle sizes were used: 80, 200 and
600 lm. Non-blasted samples were used as control. Each
of the pieces were cemented to natural teeth with a selfcuring
composite. Samples were stored in physiologic
serum at 5 C temperature. Tensile tests were performed
with a universal testing machine. Brackets treated with
sandblasted particles were measured to have an increased
adhesion as compared to the control sample. The highest
bond strength was measured for samples sandblasted with
alumina particles of 80 and 200 lm combined with micromilled
brackets. The recorded stresses did not exceed the
tensile strength of tooth enamel. |