Patients today are busier than ever. When dental treatment requires multiple appointments, coordinating work and home schedules can get complicated. But when restoration is related to failing amalgam or composite restorations with caries present, or when a tooth requires more extensive treatment than just placing in another direct restoration, at least two appointments are typically necessary. The first appointment involves preparation of the tooth to remove the existing restorative material and caries, then an impression is taken, and a provisional restoration is placed. The second appointment is scheduled after lab fabrication of the restoration to insert it intraorally.
Recent advancements in 3D printing resin materials, however, now allow the practitioner to create those indirect restorations in-office in a single appointment. Many advanced 3D printing resins now incorporate higher amounts of ceramic particles to improve the material’s wear and durability. Ceramic Crown resin (SprintRay, sprintray.com) contains over 50% ceramic and is well suited for various restorations. The chemical composition of Ceramic Crown resin is composed of methacrylate monomers and oligomers, acrylic monomers, photoinitiators, and inorganic fillers. The high ceramic content provides strength and hardness, while the polymer matrix establishes durability and shock absorption. The resin is radiopaque, polishes to a smooth finish, with excellent marginal fit and wear resistance providing long-lasting functional restorations. Flexural strength values are comparable to leucite glass ceramics (Figure 1).1-5 Shear bond strengths are comparable with lithium disilicates without any noted statistical differences (Figure 2).6 Ceramic Crown resin provides natural-like esthetics and is available in A1, A2, B1, and Bleach shades.
Ceramic Crown Workflow
Following preparation of the tooth, a typical workflow is about 45 minutes until the restoration is ready for intraoral insertion. The preparation is scanned utilizing any major scanner brand, and SprintRay’s ecosystem is compatible with any manufacturer. The files are imported into 3Shape Automate software (3Shape Inc., 3shape.com), which provides fast and reliable AI designs. Crown design is accomplished in 5 minutes or less and is returned to the dental practice.
Utilizing the Pro S Crown Kit (SprintRay), a crown can be printed in as little as 10 minutes without sacrificing the anatomical detail or esthetics of the restoration. After printing the crown with the Ceramic Crown resin, the supports are removed with a handpiece and the restoration is submerged in a small bowl of isopropyl alcohol (IPA), then brushed to remove all residue. The restoration is then dried with compressed air and a clean paper towel, placed in the ProCure 2 system (SprintRay), and the Ceramic Crown curing profile is selected. When this is completed, the restoration is again submerged in IPA to remove any residue and dried. The Ceramic Crown can be characterized and glazed using common glaze kits or polished to the patient’s esthetic needs with a lab handpiece and a lathe. These steps can be accomplished by a trained staff member or lab technician, allowing the practitioner to treat other patients until the restoration is ready for insertion.
Case Report
A 61-year-old female patient presented for a routine 6-month recall appointment for examination and hygiene. Bitewing radiographs were taken, and decay was noted on the distal crown margin on tooth No. 19 (mandibular left, first molar) (Figure 3, left). A periapical radiograph was taken to further evaluate the recurrent decay (Figure 3, right). The patient indicated no sensitivity on the tooth. Although no apical pathology was noted on the radiograph, she was advised due to the depth of the recurrent decay and its proximity to the pulp that there was a guarded long-term prognosis and endodontic treatment may be required in the future. The patient had limited finances and no dental insurance coverage. With these factors in mind, plus the absence of sensitivity on the tooth as well as no apical widening of the periodontal ligament, a new same-day printed crown was recommended to the patient. The patient agreed to the recommended treatment.
Local anesthetic was administered with an inferior alveolar nerve block. The existing crown was sectioned by creating a groove on the buccal from the crown’s margin across the occlusal surface and an instrument was used to loosen and remove the crown. The decay was further evaluated, and the tooth was re-prepared using diamond burs with a high-speed handpiece. The arch was scanned intraorally with the TRIOS 5 scanner (3Shape) (Figure 4). The opposing arch and arches in occlusion were also scanned intraorally. The data were then imported into TRIOS Design Studio (3Shape) (Figure 5).
The planned crown for tooth No. 19 was designed using TRIOS Design Studio software to optimally restore the tooth’s emergence profile and contours mesiodistally, buccolingually, and in a proper occlusal relationship with the opposing dentition (Figures 6 through 8). The virtually designed crown was removed from the virtual model in preparation to 3D print the restoration (Figures 9 through 12). Supports were then added to the virtual crown to position it on the virtual base in preparation for 3D printing (Figure 13).
The planned crown was then 3D printed on the ProS 55 printer (SprintRay) using Ceramic Crown resin (SprintRay) in shade A1 (Figure 14). Following printing, the unit was cured in the ProCure 2 unit allowing for rapid curing in 5 minutes or less, shortening the lab turnaround time, which also improves chairside efficiency. The supports were removed with a bur and the restoration was polished. Staining and glazing of the ceramic resin crown was accomplished with OPTIGLAZE (GC America, gc.dental/america), then light-cured with a VALO curing light (Ultradent, ultradent.com).
The restoration was tried-in intraorally to verify fit marginally and interproximally. Occlusion was also verified, and no adjustments were needed. The intaglio surface of the ceramic crown was cleaned with Ivoclean (Ivoclar Vivadent, ivoclar.com), which was left on the crown surface for 20 seconds, then rinsed and dried in preparation for luting intraorally. The intaglio surface was then treated with etching gel, and after
20 seconds it was rinsed and dried. Clearfil Ceramic Primer Plus (Kuraray America, kuraraydental.com) was then applied to the intaglio surface and air dried. The preparation was dried with the air syringe. Tooth Primer (Kuraray America) was applied to the tooth’s preparation. This was left for
20 seconds then air dried. Panavia V5 (Kuraray America), a dual-cure resin cement, was dispensed in Clear shade into the ceramic resin crown and the crown was seated intraorally. Excess cement was removed marginally with a microbrush. The curing light was applied to the occlusal surface for 20 seconds. This was repeated on the lingual and buccal surfaces and the resin cement was allowed to complete curing in areas that the light was not able to reach.
Diamond finishing burs were utilized to remove any residual resin cement at the restoration’s margins and polish those areas. Occlusion was checked and no adjustments were required. The patient indicated that the bite felt comfortable during simulated chewing. Clinically, the crown blended well with the surrounding dentition, eliminating the distal emergence issue that allowed food to be trapped interproximally, leading to recurrent decay (Figures 15 through 17).
The patient presented for a recall appointment. The gingival tissue around the crown showed an absence of inflammation and no bleeding on probing. The patient had no sensitivity since the restoration had been placed 5 months ago. A bitewing radiograph was taken to check the marginal interface of the ceramic crown with the tooth (Figure 18). Clinically, an absence of wear was noted on the crown and its opposing dentition.
Conclusion
Hectic schedules are common with both patients and practitioners. Typically, patients being treated with a crown requires two appointments, where the first appointment is needed with a provisional restoration being worn between appointments. Today, 3D printing allows for the elimination of that second appointment and the necessity of a provisional restoration. Advances in 3D printing and materials allow for the fabrication of a crown in a single visit.
About the Authors
Naren Rajan, DMD
Assistant Director of Digital Dentistry
Touro College of Dental Medicine
Hawthorne, New York
Gregori M. Kurtzman, DDS
Private Practice
Silver Spring, Maryland
Touro College of Dental Medicine
Hawthorne, New York
Disclosures: Naren Rajan, DMD, has been a paid lecturer for SprintRay. Gregori M. Kurtzman, DDS, was compensated for writing the article by SprintRay.
References
1. Awada A, Nathanson D. Mechanical properties of resin-ceramic CAD/CAM restorative materials. J Prosthet Dent. 2015;114(4):587-593.
2. Plotino G, Grande NM, Bedini R, Pameijer CH, Somma F. Flexural properties of endodontic posts and human root dentin. Dent Mater. 2007;23(9):1129-1135.
3. Marending M, Paqué F, Fischer J, Zehnder M. Impact of irrigant sequence on mechanical properties of human root dentin. J Endod. 2007;33(11):1325-1328.
4. Al-Thobity AM, Alsalman A. Flexural properties of three lithium disilicate materials: An in vitro evaluation. Saudi Dent J. 2021;33(7):620-627.
5. Grzebieluch W, Kowalewski P, Grygier D, et al. (2021). Printable and machinable dental restorative composites for CAD/CAM application—comparison of mechanical properties, fractographic, texture and fractal dimension analysis. Materials. 2021;14(17):4919.
6. Scientific study of shear bond strength for Ceramic Crown resin vs lithium disilicate. Unpublished data. University of Alabama at Birmingham School of Dentistry; 2023.
Figures and Images
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Naren Rajan, DMD
Gregori M. Kurtzman, DDS
