Provisional Restorations Chapter 17

Provisional Restorations Provisional coverage may be required in general, pediatric, endodontic, and prosthodontic cases. Intracoronal Extracoronal The patient wears this provisional coverage to protect the tooth for a short time. Criteria for a properly placed provisional restoration include maintenance of tooth position, protection of hard and soft oral structures, and establishment of function and esthetics.

Maintaining Tooth Position When a tooth has been prepared to receive a crown, sufficient tooth material has been removed to create a space between the adjacent tooth and the opposing teeth. A prepared tooth without occlusal/incisal and proximal contact may migrate laterally or occlusally/incisally within a few days.

Protection When the tooth is prepared, the dentinal tubules are exposed to potentially harmful thermal, chemical, mechanical, and bacterial effects in the oral cavity. These opened tubules leave the pulp vulnerable to the effects of temperature and the chemical irritants of the material placed. Materials must be biocompatible. Materials must be well adapted to the preparation.

Gingival Tissue Most crown preparations extend subgingivally, making the margins and the overall contour of the provisional restoration critical to periodontal health. Periodontal tissues are susceptible to irritation from Overcontour Overextension Overhanging margins

Function and Esthetics The provisional restoration should restore ideal occlusal/incisal and surface anatomy. Deficiencies in contour or contact of the provisional restoration may lead to problems that compromise or prevent the ideal placement of a permanent restoration. Provisional restorations must look like natural tooth structures whenever esthetics is important.

Properties Materials used to fabricate provisional restorations must have properties that comply with the specific requirement of the situation and area in which they are placed. Strength and hardness are important for posterior teeth. Esthetic concerns are important for many applications, especially in the anterior teeth.

Strength and Hardness Materials must have sufficient compressive and tensile strength to resist the forces of mastication. Surface hardness must be sufficient to resist abrasion and wear for the period through which the provisional restoration is to be worn.

Tissue Compatibility The material should not produce any additional irritation to pulpal or gingival tissues during or after setting reactions. Materials should not absorb or give off odors or taste.

Handling Materials must be fast and easy to use, reliable, and inexpensive. The material should have sufficient working time and simplified technique to allow for fabrication. The setting time must be fast and must accommodate difficult to access areas when light-activated materials are used. Materials should be repairable to account for defects and to modify fit.

Provisional Materials The choice of provisional material will depend on the type of preparation, the area of the mouth, and operator preference. Provisional materials include metals, polycarbonate, acrylics, composites, and cements. Cements are limited to intracoronal placement. Provisional acrylic and composites can be used for extracoronal coverage.

Pre-formed and Pre-fabricated Crowns The process of temporization using pre-formed crowns includes the use of stainless steel and aluminum crowns, polycarbonate, and celluloid crown forms lined with acrylic or composite materials. The pre-formed crown will become the outer surface of the provisional crown, and an acrylic or composite material or strong cement will occupy the inner portion of the crown.

Stainless Steel Crowns The stainless steel crown is the most durable of the pre-formed crowns, providing provisional coverage that lasts months and even years. The stainless steel crown has been used traditionally to restore primary teeth. These durable and economical restorations are now being considered for older adults when financial and health concerns otherwise would result in the recommendation of extractions.

Aluminum Shell Crowns Aluminum shell crowns are used for provisional coverage of posterior teeth. Lined with acrylics or composites and cemented with temporary cement, a well-fitted aluminum shell crown can last for several weeks.

Polycarbonate, Polymer, and Celluloid Crown Forms Pre-formed polycarbonate crowns are available in several sizes and shapes. These crowns are rigid and may have to be adapted with acrylic burs and disks or may be carefully cut with sharp crown scissors. They are esthetically compatible.

Customized Provisionals Acrylics and composites are used to produce high-quality custom provisional restorations for inlays, crowns, and bridges. Materials may be both self-cured and light-cured. A customized provisional for individual situations allows for better function and fit.

Acrylic Provisional Materials Acrylic materials in the form of methacrylates have been used for many years as custom temporaries. Their good esthetics, ease of manipulation, and low cost make them a popular choice over pre-formed crowns. They produce an exothermic reaction and have a high shrinkage rate.

Intracoronal Cement Provisionals Patients who require less extensive provisional coverage, as in cases with endodontic procedures, inlays, and less extensive emergency care, may benefit from cement provisionals. Cement provisionals are fabricated most frequently with zinc oxide eugenol cement, which provides palliative benefits. This may be helpful to sensitive or traumatized teeth.

Patient Education and Home Care Patients need concise instructions on how to care for their provisional restorations. Patients must be instructed not to eat sticky or hard foods in that area. Home care instructions include brushing the restoration and flossing. Remove the floss by pulling it out to the side under the contact rather than back in an occlusal/incisal direction.

Summary Provisional coverage provides protection of tooth and periodontal structures for a variety of dental procedures. Regardless of the material and technique selected, a high-quality provisional restoration must have proper contact, contour, and occlusion and must be functional and acceptable to the patient.