TOPIC: PROVISIONAL RESTORATION
🎯 KEY POINTS:
🔹Indirect technique is preferred over direct technique to fabricate provisional restoration for its accuracy and protection of pulp, in case acrylic resin is used.
🔹Prefabricated polycarbonate crowns are used on prepared single anterior tooth.
🔹Bis-acryl composite resin should not be used in long-span bridges, as these are brittle in nature.
🔹The custom-made provisional restorations are made by direct or indirect technique or combination of both.
🔹Aluminium and Tin–silver crown is used in the posterior regions only.
🔹Nickel–chromium crown is rigid, more durable and has high strength.
🔍 CLASSIFICATION OF PROVISISIONAL RESTORATION:
✳️ On the Basis of Method of Fabrication
🔺Prefabricated restoration
🔺Custom-made restoration: Mainly made by direct technique or the indirect technique or combination of both
✳️ On the Basis of Fabrication Technique
🔺Direct technique
🔺Indirect technique
🔺Indirect–direct technique
✳️ On the Basis of Material Used to Fabricate Provisional Restoration
🔺Resin-based autopolymerizing and dual-cure resins (e.g. PMMA, poly(ethyl methacrylate), bis-glycidyl methacrylate resins, bis-acryl resin composites, VLC resins)
🔺Metal-based (e.g. aluminium, stainless steel, tin–silver, nickel–chromium)
✳️ On the Basis of Time Duration
🔺Short-term temporary: For smaller time duration less than 2 weeks (e.g. single crown, short-span bridges)
🔺Long-term temporary: Longer time duration (between 2 weeks and few months). This type includes periodontally compromised teeth, in full mouth rehabilitation cases.
📢 COMMONLY USED RESIN MATERIAL FOR FABRICATING PROVISIONAL RESTORATIONS:
🔸Poly(methyl methacrylate) (PMMA)
🔸Poly(ethyl methacrylate)
🔸Polyvinylethylmethacrylate
🔸Bis-acryl composite
🔸Visible light-cured (VLC) dimethacrylate
⭐ PROVISIONAL RESTORATION IS USEFUL IN:
🔸Determining the changes in centric occlusion and incisal guidance.
🔸Determining the changes in vertical dimension.
🔸Determining the changes in occlusal or incisal plane, tooth length or contour.
🔸Aiding the diagnosis and treatment planning of periodontally compromised teeth.
🔸Aiding the preprosthetic, endodontic and orthodontic procedures.
🔸Serving as an excellent guide in procedures such as crown lengthening, ridge augmentation and pontic site preparation.
🔸Serving as a guide for the laboratory technician to fabricate the definitive prosthesis.