3-DIMENSIONAL RECONSTRUCTION OF MICROLEAKAGE PATTERN USING A SEQUENTIAL GRINDING TECHNIQUE

Dye penetration tests are very commonly used to detect the absence of a fluid seal at the tooth-restoration interface. Airlocks in the margi nal gap, leaching of water-soluble tracers during processing, and the failure of only a few sections to allow interpretation of the full pat tern, limit these tests to low reproducibility and precision. The purp ose of this present study was to generate high-resolution three-dimens ional images of waterfast tracer patterns. Cylindrical class V (3 mm d iameter, 2 mm deep) dentine-bonded resin composite restorations in buc cal coronal dentine were thermally cycled (1000 x, 8-degrees-C, 55-deg rees-C, 30 s dwell at each temperature) and then silver stained using an initial vacuum (100 mmHg pressure). Each restoration was sequential ly abraded from the free surface on wet 180 grit silicon carbide paper , producing up to 30 parallel surfaces at approximately 0.15 mm separa tion through the restoration down to the pulp. Images of the ground su rfaces were captured, and assembled by a computer image analyser progr am to give a three-dimensional model of the tracer pattern. The maximu m depths of tracer penetration below the reference surfaces were 3.00 mm, 2.09 mm, 3.16 mm and > 2.29 mm for the four specimens. Projections of the models were viewed from several directions with sections in va rious locations to allow investigation of the full tracer pattern. Thi s method allows the creation of high-resolution three-dimensional trac er patterns.