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Following an Indirect Restoration Workflow for Long-Term Success

Categories: Restorative Dentistry

Author(s): Gregory Gillespie, DDS

Date: 03-20-2020 11:41:49 am



The workflow of all indirect restorations should be dictated by what the tooth requires for a long-term, successful restoration. Not every crown needs to be bonded in, because clinically that may not increase the long-term success of the restoration. On the contrary, bonding the crown to the tooth could be the essential element for increased longevity and predictability among many restorations. Therefore, this decision is made by classifying all preparations into 1 of 2 categories: retentive and nonretentive. When preparation design dictates the decision pattern, cement selection will be definitive and clear, leading to the ultimate step of how to prepare the ceramic for the type of cement selected.


Case Presentation

In this case, a 57-year-old male presented with severe recurrent decay on tooth No. 20. A lithium disilicate indirect restoration (IPS e.max, Ivoclar Vivadent) was agreed upon by the dentist and the patient as the treatment of choice, given the force of the opposing dentition, as well as the esthetics and position of the tooth. After adequate reduction (ELECTROmatic Premium, MASTERmatic LUX M25 L high-speed, and MASTERmatic LUX M20 L lowspeed, KaVo Kerr) and an effort to retain proper resistance/retention form, a polyvinyl siloxane (PVS) impression was captured and sent to the laboratory for fabrication. Upon return from the laboratory, the preparation was evaluated. The tooth appeared to have appropriate resistance/retention form following all of the gingival contours (Figure 1). Considering the retentive nature of the preparation, I determined that the preparation would fall under the retentive preparation category, which made available a broad selection of cements for the seating procedure. In this case, we chose to use a self-adhesive resin cement (Maxcem Elite Chroma, KaVo Kerr). Self-adhesive resin cements are appropriate when some bond is desired, but the preparation also provides retention.These situations include areas of esthetic concern,when other luting agents are too opaque and certain translucent or colored cements are desired.The provisional was removed by the dental assistant, and I cleaned the preparation with air-abrasion (PROPHYflex, KaVo Kerr) (Figure 2). After try-in to verify appropriate occlusal and interproximal contacts, the e.max restoration was etched with phosphoric acid (H3PO4) for 30 seconds and washed thoroughly to remove all contamination from the patient’s saliva. The tooth was isolated using the Isolite system (Zyris). Since the restoration had proper resistance and retention form, it was not necessary to use a bonding agent on the tooth or a primer on the restoration. The self-adhesive resin cement filled the intaglio surface of the restoration (Figure 3). The restoration was firmly seated and a 3-second tack-cure was performed (Figure 4). Excess cement was easily removed, and floss was passed through the mesial and distal contacts. I held the restoration firmly in place for the next minute while the polymerization of the cement continued to progress. The restoration was allowed to fully polymerize for 4 minutes while still maintaining a dry field with the Isolite in place. The restoration was light-cured (Demi Plus, KaVo Kerr) around the margins for 20 seconds to ensure the maximum possible polymerization. With all cements, it is imperative that the full polymerization time is provided for the cement to set before any manipulation or occlusal adjustments are made. Afterward, an x-ray was obtained (DEXIS Titanium, KaVo) to make certain no extra cement had been left below the tissue that could affect the periodontal health of the surrounding bone and tissue (Figure 5). Final verification of occlusal contacts and excursive movements was evaluated, and the patient was discharged (Figure 6).

Conclusion

With all indirect restorations, the correct cementation can be achieved and implemented as part of a standardized thought progression followed by every team member. Evaluation of the prepared tooth for appropriate resistance/retention form is first determined and categorized as retentive or nonretentive. The front office staff is informed and allots the appropriate length of time for the crown seat appointment. Assistants are empowered to play an important role in the procedure, particularly when executing the cleaning of the preparation and the indirect restoration. We, as clinicians, move forward with confidence that we will have fewer crowns that loosen and fall off, reducing levels of stress and ensuring the longevity of all indirect restorations.


 
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