Acrylic Resin Crowns
As a temporary crown. Short term or Immediate term.
Pulpal protection and also Protects the finishing line of crown margins. It maintains occlusion and the Aesthetics. Ensures Against breaking of the crown prep.
Nowadays some other contemporary materials can also be also used for this purpose, like
self-curing and light-curing composites such as Protemp.
Acrylic Resin Crowns can be chair side OR lab made.
The conventional technology for the fabrication of an acrylic resin crown is the heat-curing processing of PMMA. Wax prototype is invested using dental stone in a small flask and at the end of the curing process the wax is replaced by acrylic resin material.
PMMA can demonstrate good esthetics, yet this material has a number of disadvantages – insufficient mechanical strength (poor mechanical properties), imbibition of liquids (absorbs liquids, saliva), aging with colour alteration, etc.
All these disadvantages determine the indications for treatment with acrylic resin crowns – for temporary, provisory, preliminary artificial crowns and bridge restorations, and probably the most accurate term – interim restorations.
Temporary restorations are of extreme importance to the quality of final restoration and success of the prosthetic treatment.
The interim restoration should meet a number of closely interrelated requirements – biologic, mechanical and aesthetic. It protects the pulp of the tooth from bacterial, chemical and physical damage. The preparation process, particularly the complete crown preparation can cause trauma to the pulp – between 40 000 and 70 000 dentin tubules are cut and widely opened during this process. They contain the odontoblast processes and the nuclei of the cells are positioned into the pulp.
If the prepared tooth surface remained unprotected from the harmful external factors, the damage to the pulp may be permanent and irretrievable, accompanied by pulp irritation, contamination and inflammation, and needing root canal treatment – that means a loss of its vitality.
The temporary restoration protects the marginal periodontium – this is achieved with an optimum shaping and perfect fit of the crown margins to the finish line, shoulder or chamfer. Any inaccuracy in this area, the area of the crown margin, may cause not only trauma of the periodontium, but injury of the pulp due to uncovered zones, sections, not protected by the temporary crown.
The provisional restoration should establish or maintain proper contacts with adjacent and opposing teeth – i.e. to maintain proximal contacts and occlusion.