表 1.

上颌中切牙全瓷冠牙体预备评分标准

Criteria for evaluation of tooth preparation for all ceramic crown of maxillary central incisor

Feature	Criteria
Reduction (20 points)
Incisal reduction (5 points)	1.4-1.6 mm: 5 points 1.2-1.4 mm or 1.6-1.8 mm: 3 points 1.0-1.2 mm or 1.8-2.0 mm: 1 point < 1.0 mm or > 2.0 mm: 0 point
Labial reduction (5 points)   Proximal reduction (5 points)   Lingual reduction (5 points)	1.0-1.5 mm: 5 points 0.8-1.0 mm or 1.5-1.7 mm: 3 points 0.5-0.8 mm or 1.7-2.0 mm: 1 point < 0.5 mm or > 2.0 mm: 0 point
Contour (15 points)
Labial contour (5 points)	Labial preparation has two planes providing adequate material bulk for strength/esthetics Cervical 1/2 surface parallels with the path of insertion
Proximal contour (5 points)	Smooth connected with labial and lingual surfaces, without undercut
Lingual contour (5 points)	Coincided with lingual fossa, without undercut
Taper (20 points)
Labial-lingual taper (10 points)	0°-10°: 10 points 10°-20°: 8 points
Mesial-distal taper (10 points)	20°-30°: 5 points < 0° or > 30°: 0 point
Shoulder (10 points)
(5 points)	1.0 mm shoulder
(5 points)	Obtuse inner line angles, continuous without sharp edges
Finish line (10 points)	Smooth, continuous, well-defined: 10 points Moderate roughness, moderately noncontinuous, moderate lack of definition: 5 points Significant roughness, noncontinuous, lack of definition: 0 point
Margin placement (5 points)	Equigingivally or not more than 0.5 mm subgingivally: 5 points Not more than 1 mm subgingivally or 0.5 mm supragingivally: 3 points More than 1 mm subgingivally or 0.5 mm supragingivally: 0 point
Adjacent tooth injury (10 points)	Unaffected: 10 points Minimally damaged: 5 points Severely damaged: 0 point
Preparation time (10 points)	≤20 min: 10 points 20-25 min: 6 points 25-30 min: 3 points > 30 min: 0 point