March 2012, Volume 8, Issue 3
Published by AEGIS Communications
Digitalization in Dentistry
Taking an integrated approach to the newest technologies can yield the best results for diagnosis and treatment planning.
Digitalization in dentistry has rapidly become an integral part of all aspects of the delivery of care. As new technologies are introduced, often overlooked is clinicians’ inertia as well as their ability to integrate the myriad of options into their armamentarium in order to ensure that the highest standards of care is maintained. Additionally, the desires of patients in the final outcomes of treatment must be interwoven in achieving success. For the clinician, ensuring that treatment-planning choices and treatment goals are as simple as possible to meet the esthetic challenges presented with outcomes that are predictable, reproducible, and clinically successful is paramount.
Digital radiography1 as well as three-dimensional (3-D) cone beam radiography allows an enhanced level of diagnosis and, ultimately, treatment decision-making. An increased range of restorative options becomes available with computer-aided design/computer-aided manufacturing (CAD/CAM) coupled with intraoral2 and laboratory scanners for conventional impressions. These options include: biocompatible, high-strength, all-ceramic zirconia frameworks for full-coverage crowns and fixed partial dentures; customizable implant abutments3 and, more recently, milled titanium copings for titanium-porcelain crowns and bridges; milled titanium bars for implant-retained hybrid dentures; and hybrid combination abutments with titanium implant inserts and zirconia abutment bodies. Titanium has been proven highly successful and biocompatible in implant placement,4,5 and is both economical and a biocompatible replacement for existing dental materials.6,7
Case 1—Team-Based Conservative Treatment Planning
A patient presented to the office seeking options for the replacement of recently extracted tooth No. 4 after failed endodontic therapy. Digital radiographic analysis revealed an area that appeared insufficient in vertical height without impinging on the Schneiderian membrane (Figure 1). The patient was referred to the oral surgeon, possibly for an immediate bone graft and implant placement. The use of the 3-D cone-beam computed tomography (CBCT) scan determined that, in fact, the area for implant placement was draped palatally by the sinus’ lobular pattern, and the implant could be placed buccally to the lobes without interfering with the sinus or requiring a bone graft (Figure 2). A 4.1-mm RP Biodenta® implant (Biodenta North America LLC, www.biodenta.com) was placed and restored with a titanium-modified stock abutment and a zirconia crown layered with ceramics2in1 porcelain by Biodenta (Figure 3). Additional use of the 3-D scan can be integrated with design features to develop a CBCT stent for guided implant placement as well as prefabricated temporaries if an immediate-load or temporary restoration is desired, especially in the esthetic zone. A temporary restoration was placed after implant stabilization for papillae development. The use of the machined titanium implant surface allowed for an excellent tissue response.
Case 2— Predictable Results with a Simplified Approach
Case 2 is typical of this excellent tissue response over a long period of time after implant placement in the mandibular right quadrant and the simplicity involved in the restorative process. Photographs indicate the response after 22 weeks with only a healing cap in place (Figure 4). Upon removal of the healing cap and clinically verifying implant stability, an impression transfer coping was inserted into the Biodenta 4.1 RP tissue-level implant and verified radiographically. Not only is there a snap-like feeling and fit upon insertion, the aluminum impression coping allows easy radiographic verifiability (Figure 5) of the fit, ensuring a smooth transition to delivery of the final crown. A closed-tray full-arch impression was taken and, upon removal from the mouth, was inspected. The impression coping was removed from the implant, and an analog was inserted into the coping and reinserted into the impression (Figure 6). Note that the cotton pellet, which was inserted into the screw opening to prevent the impression material from penetrating, was removed from the impression before insertion of the impression coping and analog. This step can also be done by the laboratory but, in any case, the laboratory dental technician should verify the placement. The ability of the laboratory to scan the impression and create customized restorations to both the dentist’s specifications and the laboratory requirements allows the development of a high-end restoration meeting the requirements of excellent marginal adaptation, emergence profile, contact location, and esthetic concerns. The Biodenta stock titanium abutment prepared in the laboratory was placed on the implant, verified radiographically, and then torqued to 35 Ncm with the low-profile, adjustable ratchet wrench (Figure 7). Using the low-fusing ceramics2in1 porcelain on the zirconia coping meets these requirements. To date, the author has had no ceramic failures or chipping with the ceramics2in1.8 Seen in the accompanying photographs is the excellent tissue response with biocompatible zirconia/ceramics2in1 porcelain and the development of the gingival papilla after 8 weeks (Figure 8).
Case 3— Flexibility in Treatment Alternatives
Many patients are unable, unwilling, or have a specific dental or medical condition that makes an implant solution less than ideal. The fixed partial denture is a proven treatment modality with a large number of substructure alternatives. These include gold or gold alloys, zirconia, and titanium. This case involved the use of a three-unit titanium milled substructure and layered with ceramics2in1 porcelain. Grade 2 titanium was used for this three-unit bridge; it is also indicated for single units and abutments. Grade 5 titanium is usually used for long-span bridges of four units and larger. Ceramics2in1 has a similar coefficient of thermal expansion to both the zirconia and titanium substructures. Use of the same porcelain with different substrates affords the clinician greater flexibility in predicting esthetic outcomes. Additionally, if required, the titanium can be milled as thin as 0.1 mm. The teeth were prepared in a traditional manner and full-arch impressions were taken using 3M™ ESPE™ Imprint™ Quik Step (3M ESPE, www.3MESPE.com), as was also done for the other cases presented. Figure 9 and Figure 10 show the marginal definition resulting from the five-axis milling, also used for the zirconia restorative copings before the ceramic application. Note the esthetics of the restoration immediately after insertion (Figure 11).
Case 4—Reliable Durable Options for Reconstructive and Esthetic Cases
Given the strength and durability, as well as the ability to change the opacities and translucency of the zirconia copings, the clinician has a decided advantage in combining these various characteristics to restore severely compromised cases. Thus, multiple options within the same category enable the confluence of the esthetic and structural attributes to deliver the results that the patient is seeking. Using diagnostic models and mounted casts, the desired occlusal changes and esthetic outcome was developed by the clinician and laboratory technician and previewed by the patient to ensure the acceptance of the final outcome. Given the nature of the occlusal disharmony and the patient’s decision to avoid orthodontic treatment, the mock-up also afforded the opportunity in the temporaries—which were created from the mock-up—to evaluate any functional/occlusal changes and give the patient the opportunity to make any esthetic changes. This procedure was done using a putty matrix and temporary bridge with Luxatemp® composite resin (DMG America, www.dmg-america.com). With the advent and increased use of digital milling, the temporaries can be pre-milled and even more quickly placed in the mouth with the same relining material as used above. This will also allow a more durable long-term temporary and increased marginal adaptation and enhanced gingival response. Whitening of the mandibular anterior teeth was accomplished before shade selection. The result of the all-ceramic zirconia/porcelain restoration is shown Figure 12 through Figure 14. A highly esthetic result was achieved with other ceramic materials on the Biodenta milled zirconia substructure.
Case 5 represents the simplicity in achieving excellent results with a single crown and the ability to blend color and contour with the zirconia-based restoration in the highly esthetic anterior zone. Typical preparation and reduction for an all-ceramic restoration was accomplished and an impression using 3M™ ESPE™ Impregum™ was done. The impression was sent to the laboratory with photographs for shade comparison, bite registration, and opposing models. The zirconia crown layered with ceramics2in1 porcelain was tried in. The final cementation of the crown was done according to the manufacturer’s recommendations using RelyX™ Luting Plus Cement (3M ESPE) (Figure 15 and Figure 16).
With the ever-changing landscape of available dental options, the ability of the practitioner to simply integrate the most sophisticated modalities of available treatment in a comprehensive team approach affords the patient the opportunity to receive the highest levels of care. The vertical integration of digital applications between members of the dental team and its dental laboratory partners offers clinicians the opportunity to exceed their patients’ expectations with predictable outcomes in a more simplified process.
The author would like to acknowledge the contributions of Gary Funari, DMD, who practices oral and maxillofacial surgery in Rockville, Maryland; Roland Kiss, MDT, a ceramist with DentaSwiss Laboratory; and Jong Park, CDT, a Ceramist with Uni Dental Studio in Columbia, Maryland.
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About the Author
Arthur Z. Weiss, DMD