The Effect of Guidance Elements on the Rotation of Cast Crowns During Cementation

The effect of guidance elements on the rotation of crowns was analyzed. Resin molars were prepared with curved or horizontal preparation lines. Further groups were formed with a groove or one or two boxes. Teeth were duplicated eightfold; crowns were produced and cemented with a rotational torque of 0.5 Ncm. The width of the cement gap was measured at 11 reference points. Having either one or two guidance boxes had a significant centering effect. No differences were found between both types of preparation lines. The use of a proximal guidance box may be considered to reduce torsion of a single crown during cementation.