Borders of metal and ceramic copings and their influence on aesthetics

Achieving optimum dental aesthetics is a difficult and challenging task. Fixed dental restorations play a major role in dental aesthetics. Metal ceramic and all-ceramic restorations are most commonly used in clinical practice. Metal ceramic restorations are known for its strength and reasonable aesthetics. Traditionally Metal ceramic restorations incorporate a collar which is in fact an aesthetic handicap, as the metal collar blocks light transmission through the tooth structure, darkens the root and cause discoloration of gingiva adjacent to the restoration. Generally all ceramic restorations are known for increased light transmission and diffusion. Absence of metal collar in all-ceramic restorations minimizes or in fact eliminates undesirable effects produced by the metal collar. However Zirconia in all-ceramic restorations has opacity and its optical behavior has been considered similar to metal. Both in metal and all ceramic restorations, the cervical region challenges the aesthetic achievement. Hence employing cutback in the substructure is considered to be a viable technique which can bring aesthetic improvement.