CLINICAL REPORT
Digital process for an implant-supported fixed dental prosthesis: A clinical report Jan Brandt, Dr med dent,a Hans-Christoph Lauer, Dr Habil, Dr med dent,b Thorsten Peter,c and Silvia Brandt, Dr med dentd Digital workflows play an ABSTRACT increasingly important role in A digital process is presented for an implant-supported single-tooth and a 3-unit fixed dental contemporary dentistry. Digiprosthesis (FDP) with customized abutments and monolithic prosthetic zirconia restorations. The talization in the field of prosdigital impression on the implant level was made with a TRIOS intraoral scanner (3Shape). This thetic dentistry promises process included the fabrication of an implant cast with the fused deposition modeling technique greater precision and a higher and a 3-dimensional printing process with integrated implant analogs. The process enabled the FDPs to be designed with CAD/CAM on the cast before patient contact. Designing a printed implant and more reproducible quality cast expands the use of the digital workflow in the dental field. (J Prosthet Dent 2015;-:---) of dentures.1-3 Currently, conventional prosthetics use digieconomic impact,17 which often plays a major role for tal technologies predominantly in the dental laboratory patients’ dental treatment.18 Hence it is achievable to to produce standardized high-strength ceramics and 4 develop workflows that reduce technician cost and metals. Nevertheless, the conventional impression chairside time, such as with the method described here. technique and gypsum cast remain in most dental The digital restorative process for implant-supported FDP practices, although the use of computer-assisted presented here minimizes the chairside work and at the methods is increasing to carry out clinical treatment same time maximizes the degree of precision. Moreover, steps such as impressions with intraoral scanners.5-7 the repeated screwing in and out of implant parts for Studies have shown that intraoral scanning is preferred intermittent fittings can be avoided, and the digital over the conventional method.8,9 The precision of these impression has proved to be less strain for patients.9 The devices has been shown to be clinically acceptable10-12 use of a completely digital restorative workflow in the and is easier for implant impressions because the scanimplementation of implant-supported prostheses requires bodies (Fig. 1) are readily detectable by the software, an evaluation of the fit of the abutment on the definitive unlike subgingival crown margins.13 This capability facast. It is therefore necessary to fabricate an implant cast cilitates a digital workflow for implant-supported that includes the implant analogs based on the digital data prostheses.14 of an intraoral scan with fused deposition modeling Difficulties such as restoration fitting due to (FDM), 3-dimensional (3D) printing.7 manufacturing processes with plaster casts in the context A completely digital restorative workflow is presented of conventional implant prosthetics with extensive chairthat implements an evaluation of the fit of the abutments side treatment procedures are often solved by using and the FDP fabrication on an FDM cast with integrated passive-fit elements.15,16 These passive elements result in 2-piece implant analogs (Fig. 2). the increase of the technician’s effort and have an
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Assistant Professor, Department of Prosthodontics, School of Dentistry, Goethe University, Frankfurt, Germany. Director, Department of Prosthodontics, School of Dentistry, Goethe University, Frankfurt, Germany. c Master dental technician, Department of Prosthodontics, School of Dentistry, Goethe University, Frankfurt, Germany. d Assistant Professor, Department of Prosthodontics, School of Dentistry, Goethe University, Frankfurt, Germany. b
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soft tissue was initially detected by the IS without the scanbodies to transfer the periimplant mucosa condition into the computer (Fig. 3). An additional scan was made after the insertion of the scanbodies (Figs. 3, 4). A lateral scan in maximal intercuspation was made as the interocclusal record. Finally, a digital laboratory order sheet with the selected shade (3D-Master; VITA) was prepared and sent to the laboratory via the Internet. This method reduced the chairside time to approximately 20 minutes.25
Figure 1. Scanbody.
CLINICAL REPORT A 75-year-old man in good health presented for treatment of caries and endodontic problems with a 4-unit FDP in the left maxilla. The necessary extraction of the maxillary left canine and first molar resulted in an edentulous space. The prosthetic plan provided 1 implant (maxillary left canine) as a single-tooth and a 3-unit FDP on 2 implants (maxillary left first premolar and first molar) as an alternative to a removable prosthesis. Three implants (AstraTech; Dentsply Implants) were inserted together with an external sinus floor elevation. The patient’s chief concerns after a healing period of 4 months were a fear of the impression making process because of his gag reflex and a desire for as few treatment appointments as possible. Therefore, the presented treatment option was chosen. Many studies show high accuracy of intraoral scanners (IS) and the positive impact of digital impression in implant prosthetics.19-24 Additionally, the workflow did not require a clinical evaluation of the abutments and restorations before insertion. First appointment In the first treatment appointment, the implant positions and the jaw registration were recorded with a digital scan (Cara Trios; Heraeus) using scanbodies (Scanbody 3D guide; nt-trading GmbH &Co KG) made from polyether ether ketone attached to the implants. This scanner operates with confocal microscopy, capturing thousands of images. It does not require powder and is embedded in the digital workflow of the 3Shape software, which offers the possibility of an FDM implant-cast. The periimplant
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Dental laboratory procedures The scanbodies stored in the library of the CAD software allowed a digital cast to be designed with the Model Builder (3Shape). The dimension and position of the 2-piece screw-in implant analog (DIM analog; nttrading GmbH & Co KG) was digitally incorporated into the cast via the scanbody position. As a result, the implant analog could be inserted into the prepared cast. The cast, made with FDM technique (Objet Eden260V, Polymerized Objet VeroDent MED670; Stratasys), was used to evaluate the fit of the implant CAD/CAM FDPs (Fig. 2). Customized abutments, especially in the anterior region, have better soft tissue stability.22 The individual emergence profile is a major advantage.26 Therefore, customized abutments fabricated with software (Abutment Designer; 3Shape) were used as a substructure for the restorations. The FDPs were designed anatomically and were fabricated from monolithic prosthetic zirconia by using a CAM device. The abutments and the restorations were milled in a CNC milling machine (imesicore 450i; imes-icore GmbH). Titanium blanks with a preformed abutment connection to the AstraTech implant system (nt-Preform; nt-trading GmbH &Co KG) with certificate ISO 13485 and EC Certificate 93/42EWG were used to fabricate the 1-piece titanium abutments (Fig. 5). The implant-born FDPs were fabricated with CAM without intermittent fittings of the abutments and additional scans in the patient’s mouth. The restorations were fabricated anatomically with a previously colored zirconia (Metoxit Z-CAD zirconia; Metoxit AG) with a CNC milling machine (imes-icore 450i; imes-icore GmbH). Finally, the restorations were matched to the esthetic conditions in the mouth with external stains (staining material: Cercon ceram Kiss; DeguDent. Sintering oven: Austromat 644; Dekema). This digital process chain for fabricating the planned restorations includes an evaluation of the FDPs on an FDM implant cast that was fabricated for this purpose (Fig. 6). This procedure avoids unnecessary patient treatments. For digital implant prosthetics, in particular long-span restorations, a constant and reproducible accuracy is necessary in each of the work steps following the impression. Often it is necessary to use different Brandt et al
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Figure 2. A, Digital implant analog. B, 3D printed cast.
Figure 3. A, Soft tissue scan. B, Matched implant scan.
Figure 5. nt-trading preform abutments. Figure 4. Intraoral scanbody.
programs that are rarely compatible with one another.22 This could be avoided with the applied software. Second appointment The implants were evaluated for osseointegration with a Periotest device (Medizintechnik Gulden), and
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the restorations were evaluated for fit with a silicone material (GC Fit Checker; GC Europe N.V.). The abutments were assembled with a 3-D printed transfer key (Polymerized Objet MED610; Stratasys) and tightened to 20 Ncm with a torque wrench (AstraTech; Dentsply Implants). The abutments assimilated into the
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Figure 6. A, CAD/CAM abutments on 3D printed implant cast. B, Restoration on 3D printed implant cast.
Figure 7. A, Intraoral abutments. B, Definitive restoration.
periimplant soft tissue as digitally planned (Fig. 7). The insertion of the FDPs was completed without any complications. The restorations showed a high degree of retention. Marginal adaptation in the proximal area was confirmed with a dental explorer and dental floss. The digitally generated and adjusted occlusion of both restorations did not require correction (Fig. 7, 8). The patient has been seen every 6 months as a recall. After 1-year follow-up there have been no complications with the FDPs. SUMMARY This clinical report presents a completely digital process of implant prosthodontics with digital impression making. The patient’s gag reflex was managed with this method, and his request for reduced chairside time was fulfilled. The monolithic prosthetic zirconia FDPs met expectations regarding precision, esthetics, and functionality. Furthermore, the report introduces an implant-FDM cast, which may offer more treatment options in the future. For the authors, the fabrication of long-span FDPs, complete-arch restorations, and removable dental prostheses within the context of with double-crown attachments appear to be possible with this method; meanwhile,
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Figure 8. Definitive restoration.
a prospective clinical study should be accomplished to validate the workflow in this clinical report. REFERENCES 1. Anadioti E, Aquilino SA, Gratton DG, Holloway JA, Denry IL, Thomas GW, et al. Internal fit of pressed and computer-aided design/computer-aided manufacturing ceramic crowns made from digital and conventional impressions. J Prosthodont 2015;113:304-9.
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18. Locker D, Maggirias J, Quinonez C. Income, dental insurance coverage, and financial barriers to dental care among Canadian adults. J Public Health Dent 2011;71:327-34. 19. Gimenez B, Ozcan M, Martinez-Rus F, Pradies G. Accuracy of a digital impression system based on active wavefront sampling technology for implants considering operator experience, implant angulation, and depth. Clin Implant Dent Relat Res 2015;17:e54-64. 20. Gimenez B, Pradies G, Martinez-Rus F, Ozcan M. Accuracy of two digital implant impression systems based on confocal microscopy with variations in customized software and clinical parameters. Int J Oral Maxillofac Implants 2015;30:56-64. 21. Joda T, Bragger U. Complete digital workflow for the production of implantsupported single-unit monolithic crowns. Clin Oral Implants Res 2014;25: 1304-6. 22. McDonald TR. Commentary. Utilization of digital technologies for fabrication of definitive implant-supported restorations. J Esthet Restor Dent 2012;24: 309. 23. Nedelcu RG, Persson AS. Scanning accuracy and precision in 4 intraoral scanners: an in vitro comparison based on 3-dimensional analysis. J Prosthet Dent 2014;112:1461-71. 24. Patzelt SB, Bishti S, Stampf S, Att W. Accuracy of computer-aided design/ computer-aided manufacturing-generated dental casts based on intraoral scanner data. J Am Dent Assoc 2014;145:1133-40. 25. Patzelt SB, Lamprinos C, Stampf S, Att W. The time efficiency of intraoral scanners: an in vitro comparative study. J Am Dent Assoc 2014;145: 542-51. 26. Kutkut A, Abu-Hammad O, Mitchell R. Esthetic considerations for reconstructing implant emergence profile using titanium and zirconia custom implant abutments: fifty case series report. J Oral Implantol 31 Oct 2013. http://dx.doi.org/10.1563/AAID-JOI-D-12-00274. [Epub ahead of print]. Corresponding author: Dr Jan Brandt ZZMK Carolinum Theodeor-Stern-Kai 7, Haus 29 60590 Frankfurt GERMANY Email:
[email protected] Copyright © 2015 by the Editorial Council for The Journal of Prosthetic Dentistry.
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