Violation
The preparation of an anterior tooth for a porcelain fused to metal crown should provide 1. adequate length for retention-resistance. 2. space for a thickness of metal that will resist deformation. 3. space for a thickness of porcelain that will be esthetic. 4. a single path of insertion.
All of the above.
(1) (2) (3)
(1) and (3)
(2) and (4)
(4) only