A Simplified Approach to Implant Restorations Using Innovative Digital Technology

Transcription

1 A Simplified Approach to Implant Restorations Using Innovative Digital Technology Jeffery H. Brooks, D.M.D., Russell A. Wicks, D.D.S., M.S., Timothy L. Hottel, D.D.S., M.S., M.B.A. T D A EXAM #62 Introduction The first dental digital scanner for intraoral use was introduced in the 1980s, commercially available as CEREC 1, Sirona (Bensheim, Germany). This impression system was marketed in combination with an in-office (CAD/CAM) milling device for the construction of dental restorations from porcelain blocks. Considerable expense and learning expertise were required to implement such early technology. 1 More contemporary systems have reduced costs, increased applications, improved accuracy, and greater ease of use. A trending method deploys the scanning device chair side and the transfer of digital information electronically, directly to the dental laboratory. In some arrangements the scanner can be provided by the laboratory. Upon receiving the scan and the work authorization, the restoration is manufactured by the laboratory and returned to the dentist for placement. This article describes a clinical case using this method for production of bilateral implant supported posterior crowns. Dental crown restorations have been historically constructed using an indirect protocol. The tooth is prepared, an impression is made of the prepared tooth, a model is made from the impression, and the crown is constructed on the model. In the case of a crown supported by a dental implant, a transfer pin or impression coping attached to the implant is substituted for the prepared tooth. This indirect approach has several steps, all of which have inherent potential ABSTRACT Digital impressions and CAM/CAD systems are currently burgeoning dental technologies. This article presents a case study describing the clinical protocol necessary to produce multiple crown restorations supported by dental implants. for creating or perpetuating fabrication errors; distortion of the impression material and tray, expansion of the dental Figure 1: The TRIOS scanning wand and its stand connected to a PC. Figure 2: Scanning abutments matching specific implants. stone, and errors associated with casting procedures may each lead to production of a restoration which is less than clinically ideal. 2,3,4,5 Transferring a digital image directly to a milling device for constructing a crown reduces the number of steps and chances for compounding of production errors. Several contemporary publications have confirmed the accuracy of dental restorations constructed from these processes to be equal to or greater than those derived by conventional indirect technics. 6,7,8,9,10 The intraoral scanning device used in this case presentation is the 3Shape TRIOS, 3Shape Corporation (Denmark). This is a large footprint system, which uses a video-rate, parallel confocal measuring technique to capture related likenesses of entire dental arches. The scanning wand may be mounted with an upright mobile unit (Trios Monochrome Cart ) or a free standing unit teamed with a configured portable computer as shown (Figure 1). Integral to the digital data capture are the scanning abutments. These are explicitly designed for use with individual implant systems (Figure 2). They contain specific geometries, which when scanned complement the locations of the implant platforms in three dimensions within the built digital image. These are 94-2 A Simplified Approach to Implant Restorations Using Innovative Digital Technology Continuing Education Exam #62 41

2 Figure 3: Patient with healing abutments in situ. Figure 4: Scanning abutments are joined to the implants. proprietary, matched to specific implant manufacturers products, and provided by the dental laboratory, which will construct the restorations. (Glidewell Dental Lab, Newport Beach, California) Clinical Procedure A 47-year-old African-American female reported with bilateral implants in the mandibular second premolar and first molar edentulous areas. Following second stage surgical procedures, the healing abutments had been in place for two weeks. Soft tissue was well-healed, firm and stable. Placement of the implants was confirmed to be in acceptable locations to support single crown restorations (Figure 3). After removal of the healing abutments, the appropriate scanning abutments were installed on the implant platforms (Figure 4). Unlike metallic impression copings or transfer pins, complete seating of plastic components is difficult to determine radiographically. Therefore, clinical appraisal of the unions must rely on visual and tactile confirmation. The attachment screws were tightened using a hand driver. Once the scanning abutments were in place, the optical wand was navigated around the entire mandibular arch using occlusal-anterioposterior and buccolingual sensor directions (Figure 5). A similar scan was made of the entire maxillary arch. A final scan was used to relate the two previous images together by scanning the teeth laterally while the mandible was located in the maximum intercuspation position. These sweeping motions input data as a continuous video, recording up to 3000 images per second. Previous generation optical scanning systems triangulate and combine much fewer singularly captured images. These scans formed a threedimensional image representing an anatomical master cast with the related implant platforms. This image could be manipulated on an x, y, or z axis (Figures 6 and 7). The abutments and the crowns were conceived (Computer Assisted Design, CAD) and created (Computer Assisted Manufacture, CAM) using this virtual model combined with a milling device in the dental laboratory (Figures 8, 9, and 10). After the scanning procedures, the plastic abutments were removed, the healing abutments replaced, and a shade match performed visually using a manufactured guide. Custom milled titanium abutments and Zirconium crowns (BruxZir, Continuing Education Exam #62 42 Figure 5: Intraoral use of the TRIOS scanning wand. Figure 6: Occlusal scan build. Journal of the Tennessee Dental Association 94-2

3 Figure 7: Sagittal scan build. Figure 8: Abutment CAD. Glidewell Dental Lab, Newport Beach, California) were returned from the dental laboratory without any accompanying model work (Figure 11). The positions of the abutments were identified with small etched numbers on the buccal surface which corresponded to the missing teeth locations. On the day of delivery, the healing abutments were removed and the custom abutments installed. These abutments possessed tailored dimensional adaptations to support the morphology of the crowns and ideal margin locations as they emerge through the mucosa (Figure 12). The correct fixations of the abutments to the implants were confirmed by radiographs and the attachment screws were torqued to the recommended force of 30 N/cm. Following the abutment installation, each crown was individually fitted and adjusted with its adjacent interproximal contacts (Figure 13). After complete seating was achieved and verified for each crown, the centric and lateral excursive occlusal contacts were evaluated. The exactness of construction is reflected in how few adjustments were actually required. Cementation was accomplished using a resin luting media (Unicem Rely-x, 3M/ ESPE, St. Paul,MN ). Excess cement was easily removed from the interface due to the access at ideal margin locations. Bilateral Radiographs were made to confirm that no residual cement remains adjacent to crown margins (Figure 14). Conclusion Benefits of this protocol for multiple single crown production include: reduced chair and production time, reduced inaccuracies, reduced costs, customized/ accuracy of fit, gingival capture, reduced adjustments, ideal margin location and ease of cementation. The lack of casts and articulators may seem somewhat unsettling to the seasoned practitioner who has spent a career with models. However, the excellent clinical results obtained by this method suggest a future paradigm shift away from more established protocols. The digital age in dentistry can successfully include the capture, design, and creation of multiple single-unit implant supported restorations. Disclosure: The authors did not report any disclosures. References: 1. Birnbaum NS, Aaronson HB. Dental impressions using 3D digital scanners: virtual becomes reality. Compend Contin Educ Dent 2008 Oct;29(8):494, 496, Figure 9: Crown CADs occlusal view. Figure 10: Crown CADs sagittal view with opposing occlusion A Simplified Approach to Implant Restorations Using Innovative Digital Technology Continuing Education Exam #62 43

4 Figure 11: Zirconium crowns and custom milled abutments received from the dental laboratory. Figure 12: Custom abutments installed bilaterally. Figure 13: Crowns placed and adjusted prior to cementation. Figure 14: Periapical radiograph of installed crowns and abutments. Continuing Education Exam #62 2. Cho GC, Chee WW. Distortion of disposable plastic stock trays when used with putty vinyl polysiloxane impression materials. J Prosthet Dent 2004 Oct;92(4): Chen SY, Liang WM, Chen FN. Factors affecting the accuracy of elastometric impression materials. J Dent 2004 Nov;32(8): Linke BA, Nicholls JI, Faucher RR. Distortion analysis of stone casts made from impression materials. J Prosthet Dent Dec; 54(6): Mitha T, Owen CP, Howes DG. The three-dimensional casting distortion of five implant-supported frameworks. Int J Prosthodont May-Jun;22(3): Howell KJ, McGlumphy EA, Drago C, Knapik G. Comparison of the accuracy of Biomet 3i Encode Robocast Technology and conventional implant impression techniques. Int J Oral Maxillofac Implants Jan-Feb;28(1): doi: / jomi Svanborg P, Skjerven H, Carlsson P, Eliasson A, Karlsson S, Ortorp A. Marginal and internal fit of cobalt-chromium fixed dental prostheses generated from digital and conventional impressions. Int J Dent. 2014;2014: doi: /2014/ Epub 2014 Mar Lee SJ, Betensky RA, Gianneschi GE, Gallucci GO. Accuracy of digital versus conventional implant impressions. Clin Oral Implants Res Apr 10. doi: /clr [Epub ahead of print]. 9. Ng J, Ruse D, Wyatt C. A comparison of the marginal fit of crowns fabricated with digital and conventional methods. J Prosthet Dent Mar 11. pii: S (14) doi: /j.prosdent [Epub ahead of print]. 10. Almeida e Silva JS, Erdelt K, Edelhoff D, Araújo É, Stimmelmayr M, Vieira LC, Güth JF. Marginal and internal fit of four-unit zirconia fixed dental prostheses based on digital and conventional impression techniques. Clin Oral Investig Mar; 18(2): doi: /s Epub 2013 May 29 Jeffery H. Brooks, D.M.D., Associate Professor, Department of Oral and Maxillofacial Surgery, University of Tennessee College of Dentistry, Memphis, Tennessee. Contact Dr. Brooks at [email protected] or Russell A. Wicks, D.D.S., M.S., Professor and Chairman, Department of Prosthodontics, University of Tennessee College of Dentistry, Memphis, Tennessee Timothy L. Hottel, D.D.S., M.S., M.B.A., Professor, Department of Prosthodontics and Dean, University of Tennessee College of Dentistry, Memphis, Tennessee 44 Journal of the Tennessee Dental Association 94-2

5 Questions for Continuing Education Article - CE Exam #62 Publication date: Fall/Winter Expiration date: Fall/Winter This exam is also available online. If you take the exam online, you can pay with a credit card and print out your certificate in a matter of minutes. Visit the TDAs website at 1. The direct method of acquiring a digital impression for implant restorations has all of the advantages except: a. Reduced chances for creating perpetuation fabrication errors. b. Reduces the number of steps and chances for compounding production errors. c. Are less accurate than the conventional impression tray and casting procedures. d. Can allow for direct production of a restoration in office via a milling device. 2. The Trios system described in this case study: a. Employs an in-office milling device b. Uses an indirect crown construction protocol c. Inputs data with an optical wand using a sweeping motion d. Scans encoded healing abutments 3. Using the optical scanning procedure in this article has the capability of capturing the soft-tissue bed topography above the platform by: a. Taking a single scan of the implant scan body and extrapolating the soft tissue contours. b. Requires the traditional PVS scan of the soft tissue bed if soft tissue contours are required. c. Two optical scans of the implant site are acquired. One with the scan body and another without the scan body. d. It is impossible to get the soft tissue contours with this technique which is a disadvantage of this technique. 4. All of the following are true except: a. The 3Shape Trios system used in this article uses video-rate capture technology to allow for rapid acquisition of the tooth and arch of interest. b. Scan abutments that are required for digital implant impressions are specific for each implant manufacturer and platform type. c. This techniques is only stable for single tooth restorations. d. The digital technique is more accurate than convention techniques primarily due to the potential for compounding processing errors associated with the latter technique. 5. Scanning abutments used in this protocol were: a. Generic b. Radiopaque c. Provided by the scanner company d. Fitted to an internal implant interface connection 6. The restorations created in this case study: a. Are supported by custom milled zirconium abutments b. Were constructed as porcelain fused to metal crowns c. Attached directly to the implants d. Required few adjustments ADA CERP Recognized Provider The Tennessee Dental Association is an ADA CERP Recognized Provider. ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses or instructors, nor does it imply acceptance of credit hours by the boards of dentistry. Concerns or complaints about a CE provider may be directed to the provider or to ADA CERP at Continuing Education Exam # A Simplified Approach to Implant Restorations Using Innovative Digital Technology - Exam Questions 45

6 Date exam taken: Answer Form for TDA CE Credit Exam #62: A Simplified Approach to Implant Restorations Using Innovative Digital Technology T D A EXAM #62 Publication date: Fall/Winter Expiration date: Fall/Winter Circle the correct letter answer for each CE Exam question: 1. a b c d 2. a b c d 3. a b c d 4. a b c d 5. a b c d 6. a b c d Please complete the following course evaluation. These answers do not affect the grading process. Assess your mastery of the material Full Partial No Your comprehension of material Excellent Fair Poor Appropriateness of the material Excellent Fair Poor Was the material adequately in-depth? Yes No Additional feedback should be ed to the TDA at [email protected] Cost per exam per person is $ If you correctly answer four of the five questions, you will be granted one (1) continuing education credit. Credit may not apply toward license renewal in all licensing jurisdictions. It is the responsibility of each participant to verify the CE requirements of his or her licensing or regulatory agency. This page may be duplicated for multiple use. Please print or type. ADA ID Number (Dentist Only): License Number of RDH: Registration Number if RDA: Name (Last/First/Middle): Office Address: City/State/Zip: Daytime Phone Number : ( ) Component Society (TDA Member Only): Continuing Education Exam #62 46 Dr. (Auxiliary Staff: Please provide name of Employer Dentist) All checks should be made payable to the Tennessee Dental Association. Return the Exam Form and your check or credit card information to: Tennessee Dental Association at 660 Bakers Bridge Ave., Suite 300 in Franklin, TN The form may be faxed to if using a credit card (use your TDA/Bank of America card, MasterCard or Visa ONLY): Signature: Card #: Three-digit CVV2 Code (on back of the card following the card number): Name as it appears on the card: Exp. Date: Do not write in this space - for TDA Administration purposes only Check #: CC Paid w/doctor s CC Journal of the Tennessee Dental Association 94-2