Prefabricated Crowns (e.g. 3M Iso-Form™ Crowns) Advantages • Easy to use • Significant time savings over acrylic • Broad applications from short term to long-term coverage Disadvantages • Limited to single units • Correct marginal adaptation of crown is critical Acrylics (e.g., Jet by Lang, Snap by Parkell) Advantages • Low cost • Esthetic • Versatile (either single or multiple units) Disadvantages • Mixing required (powder/liquid) • Strong objectionable odor for patients and staff • A significant amount of heat is released during the setting reaction. This exothermic reaction has the potential to cause pulpal damage if not carefully controlled. • Difficult to repair • Significant waste/clean-up • High volumetric shrinkage (Methyl Methacrylates e.g. Jet) • Poor physical properties and color stability (R’Methacrylates e.g. Snap) Composite Resin Systems (e.g. Luxatemp, DMG/Zenith) Self-Cured Resin Materials Advantages • Low odor • Minimal heat generation • Lower shrinkage than acrylic • Very good esthetics • Some systems use auto-mix delivery • Can be repaired using composite Disadvantages • More expensive than acrylic • Many do not have an extended flexible stage • Viscosity cannot be altered • Different handling characteristics than acrylic • Resins form a sticky oxygen inhibited layer • Some materials are more brittle than acrylic Multiphase Materials (e.g. 3M Iso-Temp Temporary Material) Advantages • Automixed (no mixing or reloading of syringes) • Direct delivery to matrix • Operator control (extended working time in flexible stage) • Light cure on demand • Minimal odor, shrinkage and heat generation • Good wear resistance • Good esthetics • Multiple shades Disadvantages • More expensive than acrylic • Viscosity cannot be altered • Resins form a sticky oxygen inhibited layer Copyright © 1999 3M. All rights reserved.