2Donova TE, Cho GC. Soft tissue management with metalceramic and all-ceramic crown systems[J]. Journal of the CaliforniaDental Association, 2008:12-117.
3Hung SH, Hung KS. Marginal fit of porcelain-fused-to-metaland two types of ceramic crown[J]. The Journal of ProsTheticDentistry,2010:111-114.