ACCURACY OF FREELY ADAPTED RESIN RECORD BASES

Forty autopolymerizing resin record bases were made; 10 bases were ada pted by finger pressure on tray resin material dough, 10 bases by spri nkling orthodontic resin, and 10 of repair material by either of the t wo previous techniques. Stone casts and acrylic resin bases were secti oned at canine, premolar, and molar coronal planes. Width of the gap b etween base and cast and the thickness of the base were measured at th e buccal sulcus, ridge crest, lateral palatal slope, and palatal midpo int. Measurements were made through the eyepiece of a microhardness te ster. Statistical analysis of 760 pairs of measurements revealed that (1) sprinkled bases fit better than finger-adapted dough bases; (2) sp ecifically formulated materials fit better than repair material with e ither technique; (3) gap widths differed at different areas of the sam e base; and (4) gap width was not related to base thickness at any poi nt.