Methods: Seven teeth in four patients (four premolars and three molars) were treated by final year dental students under supervision in the university clinic. Before and after the restoration, we took impression using irreversible hydrocolloid and made study casts. Then the casts were cut in the same position using occlusal index. On the cross section surfaces, we divided the crown into six equal parts parallel to the occlusal plane. And we measured the crown width in the bucco-lingal direction at each five position.
Results: The crown widths of restorations were 0.58 ± 0.41mm (premolars), 0.08 ± 0.31mm (molars) wider than those of the teeth before preparation.
Conclusions: The crown widths of restoration were significantly larger than those of the teeth before treatment in the case of premolars, but there were no significant differences in the case of molars (paired Student's t-test, p<0.01).