The Single-Unit Crown Total Practice Solution™
Enhance procedural reliability and restoration longevity
Jason H. Goodchild, DMD
For restorative dentists, the single-unit crown procedure has a significant impact on patient satisfaction and office profitability. Comprised of multiple procedural steps that involve the dental team, a dental lab, and two separate appointments, the success of conventional single-unit crown fabrication is dependent on many factors. To help dentists simplify the five critical procedural steps involved, Dentsply Sirona Restorative has introduced the Single-Unit Crown Total Practice Solution™—a portfolio of high performance products, education, and support that can enhance procedural reliability and restoration longevity. The following case describes how the Single-Unit Crown Total Practice Solution was used to help restore tooth No. 3 in a 32-year-old, female patient:
Step 1: Creating an accurate matrix impression (Figure 1). When the tooth is intact, or can be duplicated to help speed up the provisionalization process, a matrix impression (ie, a pre-operative impression or preliminary impression) is needed. Using a material with excellent detail reproduction and dimensional stability allows for not only well-contoured and accurate provisionals but also storage of the impression in case a remake is needed.
After anesthetizing the area and before tooth No. 3 was prepared, Algin•X™ Ultra Alginate Alternative impression material was used in a closed-bite tray to record the matrix impression. To ensure the patient was biting normally and maximum intercuspation was achieved, tooth contact was verified by holding the impression up to a light source.
Step 2: Making a final impression (Figure 2 through Figure 4). Once the tooth preparation has been completed, a final impression to capture the details of the tooth, adjacent teeth, and tissues must be recorded. To capture the final impression of tooth No. 3, two formulations of Aquasil® Ultra+ Smart Wetting® Impression Material XLV and Heavy) were selected as a part of a one-step, dual-viscosity impression in a closed-bite tray. Featuring several timing and viscosity choices, a low intraoral contact angle for excellent hydrophilicity, and market-leading intraoral tear strength, Aquasil Ultra+ can provide practitioners with sufficient material options to handle every clinical situation.
A small amount of Aquasil Ultra+ XLV Fast Set wash material was bled outside the mouth and then immediately syringed around the moist preparation using a digit cartridge system. Care was taken to syringe the wash material around the preparation twice, while keeping the intraoral tip submerged in the material to avoid air entrapment and bubbles. The closed-bite tray containing Aquasil Ultra+ Heavy tray material was then seated within the wash material’s 35 second working time to help prevent mixing errors that can create pulls or drags within the impression and result in poor detail reproduction. After waiting the minimum time indicated for removal (2.5 minutes from the start of the mix), the impression was removed from the patient’s mouth and evaluated.
Step 3: Fabricating the provisional crown (Figure 5 and Figure 6). Provisional restorations have several important purposes, including protecting the tooth, restoring function and esthetics, and helping to facilitate tissue healing. To help realize these benefits, the restoration must be lifelike, highly polishable, and strong.
Integrity® Multi•Cure Temporary Crown & Bridge Material was injected into the matrix and re-seated into the mouth for 90 seconds. After removing the matrix impression with the still-setting provisional inside, final set can be achieved by curing with light for 20 seconds. Integrity Multi•Cure was chosen because it provides a time-saving benefit without compromising strength or esthetics.
Step 4: Cementing the provisional crown. Beyond creating a provisional that is nice-looking, smooth, and strong, creating one that protects the tooth and aids in tissue healing requires that the provisional remain firmly cemented on the preparation.
Integrity® TempGrip Temporary Crown & Bridge Cement features two important advantages for the dentist and patient. First, because the material is designed to adhere strongly in the presence of natural moisture during cementation (as opposed to drying the tooth), the chances for postoperative sensitivity are minimized. And second, when the provisional is removed, most of the excess cement will be in the restoration with very little on the tooth, making cleanup easier for the dentist and less sensitive for the patient.
A thin layer of Integrity Tempgrip cement was applied to the inside of the provisional crown, which was then seated on the moist tooth within 1 minute of mixing. After 2 to 3 minutes, the material self-cured, the excess was removed, and the patient was released.
Step 5: Definitive cementation of the final restoration (Figure 7 and Figure 8). Definitive cementation is the final step in the single-unit crown procedure, but it is just the beginning of the clinical life of the crown. From the dentist’s perspective, selecting a definitive cement that can be used for all substrates, has excellent physical properties, and is easy to clean up is ideal. For our patients, minimizing postoperative sensitivity and maximizing performance are vital to restoration success. Self-adhesive resin cements can marry the needs of dentists with the demands of patients, but historically, the associated cleanup has been challenging for clinicians.
To minimize the stress of cementation, Calibra® Universal Self-Adhesive Resin Cement was selected for the definitive cementation of tooth No. 3. It provides the strength of resin, includes several shade options, and features an extended gel phase for easier cleanup. After treating the intaglio of the all-ceramic restoration per the manufacturer’s recommendations, Calibra Universal Self-Adhesive Resin Cement was placed into the crown, and it was seated in the mouth. For restorations that are not light transmissible, the material will reach a gel state in approximately 2 minutes; however, to facilitate cleanup in this case, the excess cement was tack cured to reach a gel state by light curing the buccal and lingual surfaces for 5 seconds each. While maintaining stabilization of the crown to prevent movement, the excess material can be removed and the interproximal areas flossed. After a final check of fit and occlusion, the restoration was complete and the patient was released.
The single-unit crown procedure has many steps, and each one plays an important role in achieving a successful outcome. Dentsply Sirona Restorative’s Single-Unit Crown Total Practice Solution is intended to provide clinical benefits for each of these procedural steps. However, by ensuring that the portfolio of products not only work well individually, but also work well together, the Single-Unit Crown Total Practice Solution creates a synergy for the procedure that increases efficiency and delivers long-term clinical success.
About the Author
Jason H. Goodchild, DMD
Chairman of the Department of Diagnostic Sciences
School of Dentistry
Clinical Education Manager
Dentsply Sirona Restorative
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