Optimizing Efficiency in Single-Unit Crown Procedures
Temporization made simple
Chad J. Anderson, MS, DMD
In many practices, the lengthiest standard, single-tooth appointment is the single-unit crown procedure, which also consumes the most materials, making it an ideal procedure for studying ways to optimize time and resources. A significant portion of chairtime is taken up by the temporization phase, which in the author’s practice is handled by registered dental assistants, freeing up more of his time to treat patients.
In the past, the author has used aluminum or acrylic for temporization, but he is now using new bis-acryl materials. This newest class of temporary materials has many benefits that the traditional alternatives do not.1,2 Acrylic, for example, has several deficiencies; it is not optimally esthetic in color matching, and it can be difficult to handle because of the variability in setting time. Bis-acryl materials, however, have good durability and compressive strength as well as flexural properties.3,4 Preformed aluminum temporaries can be very effective in terms of cost and time efficiency, but they are not a viable option for patients who are highly conscious of esthetics. They can also be durable and easy to place, but the gingival tissues can have an adverse inflammatory response as the gingival margin is compromised and impinged upon. Bis-acryl materials, however, fit the criteria for an efficient, highly esthetic crown-and-bridge temporary material that is durable, easy to use, and cost-effective.5
An 18-year-old woman presented with a history of endodontic treatment of teeth Nos. 2, 3, and 30. They were reduced to the ideal dimensions to optimize restoration with full-coverage porcelain-fused-to-metal crowns (Figure 1). In preparation for temporization, a shade was identified using the VITA classical shade guide and recorded for the temporary. Prior to preparation, a triple-tray impression was taken with a poly ethyl vinyl material to capture the initial tooth form and anatomy that will be replicated in the restoration. Note that this step is crucial for the success of the final temporary. If the teeth that will be temporized are missing or have an altered tooth structure as a result of a fracture or a prior reduction (eg, for endodontic treatment), it is important to restore the tooth to normal form and contour prior to taking the impression. The author typically uses a flowable composite to quickly return the tooth to original form and functional anatomic shape.
After the triple-tray impression was taken, it was confirmed that the impression had captured the anatomical form of the teeth to be temporized with no voids or defects. The impression was set aside.
The initial tooth was prepared to 0.20 mm to 0.50 mm below the free gingival margin. This was performed by using a two-retraction-cord technique using Ultrapak® #00 retraction cord (Ultradent, www.ultradent.com) both for the initial tension cord and the second retraction cord. Both cords were first saturated in aluminum chloride hemostatic solution to prevent bleeding. After hemostasis was confirmed, the top retraction cord was removed and a master impression was taken. The use of retraction cord and a hemostatic agent allowed for optimal esthetics and also maintained the margin of the preparation for temporization.
Temporization began following tooth preparation. The initial triple-tray impression was filled with Ultradent’s ExperTemp® temporary crown and bridge material in color A1. Air bubbles were avoided by ensuring that the tip of the applicator stayed within the bulk of the expressed temporary material (Figure 2). The tray was loaded and placed into the patient’s mouth. The assistant took care to re-index the triple tray into the proper teeth. The patient was asked to bite down into the triple tray and hold for the required set time. ExperTemp material has a working time of 2 minutes. Once the set time was complete, the patient was then asked to open her mouth and the triple tray was retrieved.
Often, the newly formed temporaries will remain on the tooth. Sometimes they will remain in the impression form (Figure 3). ExperTemp material still has some plasticity at this stage and can be easily retrieved even if small undercuts are present. If any undercuts are present, a pair of locking hemostats may be used to retrieve the temporary from the tooth.
The bis-acryl material will have a sticky layer of oxygen-inhibited uncured resin that can be maintained. This layer is bondable to composite if any voids need to be filled or if any additions need to be made. A flowable composite resin can be used to fill these voids and light-cured. Although bis-acryl materials are self-cured, the resin can be combined with most flowable composites. The tacky oxygen-inhibited layer of resin is ideally removed before finishing. Removal can easily be achieved by wiping the temporary with cotton gauze saturated in 70% ethyl alcohol. Additions can still be made after the oxygen-inhibited layer is removed, but a bonding agent will need to be utilized. If no additions need to be made, finishing and adjusting can begin.
In the case of this patient, a fine diamond bur was first used to remove any flash and to idealize contour and shape (Figure 4). This was followed with a polishing brush to give the restoration an esthetic finish and shine (Figure 5). Fit was confirmed and interproximal contacts were checked. Occlusion was checked with articulating paper and adjusted to light contacts.
A temporary cement, such as Fynal (Dentsply, www.dentsply.com), was used because of its good retention and easy cleanup and retrieval of the temporary prior to permanent restoration cementation (Figure 6). The cement material was allowed to set in the patient’s mouth for 2 minutes and the excess was removed with a universal scaler. The interproximal contacts were flossed to clean any excess material (Figure 7). The patient was instructed to floss her teeth, but was cautioned to only floss down through the contact and to pull the floss out the side of the contact, as flossing upward could dislodge the temporary. The patient was also cautioned against sticky and adherent items like gum and caramel.
The patient was then released with a durable, comfortable, and esthetic temporary restoration.
She was recalled 2 weeks after the tooth preparation and temporization, experiencing no discomfort and said that the temporaries felt and functioned like her own teeth. The patient reported tolerating the treatment very well and she was very happy with the results.
ExperTemp bis-acryl temporary material was an easy material to apply and use, and had desirable results for the patient. Additionally, it significantly reduced the chairtime for the author’s temporization procedures, which assisted in optimizing the time in his practice.
1. Shim JS, Lee JY, Choi YJ, et al. Effect of light-curing, oxygen inhibition, and heat on shear bond strength between bis-acryl provisional restoration and bis-acryl repair materials. J Adv Prosthodont. 2015;7(1):47-50.
2. Knobloch LA, Kerby RE, Pulido T, Johnston WM. Relative fracture toughness of bis-acryl interim resin materials. J Prosthet Dent. 2011;106(2):118-125.
3. Hagge MS, Lindemuth JS, Jones AG. Shear bond strength of bis-acryl composite provisional material repaired with flowable composite. J Esthet Restor Dent. 2002;14(1):47-52.
4. Fliesch L, Cleaton-Jones P, Forbes M, et al. Pulpal response to a bis-acryl-plastic (Protemp) temporary crown and bridge material. J Oral Pathol. 1984;13(6):622-631.
5. Perry RD, Magnuson B. Provisional materials: key components of interim fixed restorations. Compend Contin Educ Dent. 2012;13(1):59-62.
Chad J. Anderson MS, DMD
Department of Prosthodontics and Operative Dentistry and Research
Tufts University School of
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Ultradent Products, Inc.