[Effect of full crown preparation with ultrasound instrument on marginal adaption: a randomized controlled trial].

Purpose: To study the effect of full crown ultrasound preparation on crown margin.

Methods: Thirty-two patients with 35 units of full crown were randomly divided into 2 groups. Teeth in the experimental group were prepared with ultrasound diamond instrument while teeth in the control group were prepared with a high-speed hand piece with regular diamond burs.

[Analysis of retention of 3 different aesthetic Co-Cr-Mo alloy clasps on premolars].

Purpose: To evaluate the 3-D surface topography of ultrasonically prepared tooth.

Methods: Ten extracted human maxillary premolars were prepared for crowns. A split-tooth model was used to refine the margins: half of the margin was finished with traditional rotary instruments, the other with ultrasonic instruments.

[Evaluation of the clinical effect of the teeth with subgingivally involved defect conserved by crown lengthening surgery].

Purpose: To evaluate the clinical effect of the teeth with subgingivally involved defect which were conserved by crown lengthening surgery.

Methods: 62 teeth, with defect subgingivally from 1.5 mm to 4 mm, mobility degree(MD) View Article and Find Full Text PDF