October 2016
Volume 7, Issue 10

AvaDent Digital Denture and Implant Solutions

New workflows help improve collaboration between clinician and technician

By Robert Kreyer, CDT

Different digital denture workflows exist, depending on a patient’s needs and variables involved when designing complete dentures within the digital prosthetic space of the oral environment. The AvaDent milling process offers the option to use the Core or Share digital workflow process. The AvaDent Core is the company’s in-house central milling, whereas the Share is milled in your laboratory using Avadent’s file and PMMA pucks. This article will discuss the Wagner Try-In (WTI) developed by Stephen Wagner, DDS, and present a digital workflow that he used. Dr. Wagner desired the advantages of a digital denture combined with traditional clinical removable prosthodontic techniques in three 30-minute appointments.

Clinical No. 1: As with all removable prosthodontic techniques, excellent impressions that capture all necessary edentulous anatomy including proper extended peripheral borders are absolutely necessary for digital denture success. The clinician evaluated the edentulous condition and then took maxillary and mandibular border molded definitive impressions. These edentulous impressions were then sent for digital scanning.

Technical No. 1 : An impression can be scanned or a model can be created and then scanned if desired. One of the objectives in removable prosthodontics is to eliminate as many variables as possible during case design and clinical treatment. One variable that can be eliminated is the creation of a stone cast. Scanning edentulous impressions has proven to be very successful and accurate, eliminating the expansion of stone when creating a cast.

The AvaDent digital denture starts with completing and submitting a Digital Online Work Order. This digital work authorization improves communication and collaboration by leading the user through a series of case planning questions, thus eliminating variables from the start (Figure 1).

Once the AvaDent Digital Rx was completed and all necessary data was available in STL scan files, they were sent to AvaDent for digital planning and design.

AvaDent No. 1: The file then went through a specific workflow process. It was cleaned up so AvaDent Digital Denture Designers could analyze the complete prosthetic situation based on the information provided.

The digital model analysis was conducted on the maxillary scan file to analyze the edentulous anatomy with specific reference to incisive papilla and hamular notches relationship. It has been found in prosthodontic literature that the hamular notch to incisive papilla (HIP) is a viable reference to determine the occlusal plane in complete denture prosthetics (Figure 2).

Based on a papillameter reading, which measures the maxillary lip at rest and high lip line, a clinical/technical incisal edge position was established. The plane of occlusion was calculated using the papillameter record in relation to hamular notches. The mandibular scan file was brought in to verify the established digital plane of occlusion in relation to the retromolar pads. The parallelism of the maxillary and mandibular ridges were then evaluated to insure that occlusal forces would be at a right angle to the area of support, increasing the stability of the digital denture prosthesis (Figure 3).

A Digital Occlusal Rim was then designed to create a reference for placement of the digital tooth arrangement. The Digital Occlusal Rim was contoured, providing information on labial inclination of emergence profile, buccal corridor, incisal edge or smile line position, and plane of occlusion (Figure 4).

Once the Digital Occlusal Rim was designed and contoured, creating a reference matrix, the digital tooth arrangement was established (Figure 5).

At this point, the team had designed a digital preliminary set-up with a milled base that would be used during a records appointment to establish maxillo-mandibular relationships, vertical dimension of occlusion, centric relation, or myocentric if recording a neuromuscular position. A direct correlation exists between base stability and accurate record relationships.

The WTI had the advantages of a processed base with anterior teeth set in wax and posterior occlusal rims for indexing record. In the maxillary, a second pre-molar was omitted, giving the clinician ability to move the anterior eight teeth further palatal or a posterior position. The mandibular arch had six anteriors, enabling the clinician to alter the VDO and move the anteriors labial or lingual. The mandibular posterior was used for an Aluwax record index (Figure 6). This would be used in the second clinical appointment, enabling the clinician to establish records with a stable and retentive milled digital denture base. The clinician was able to adjust the intaglio of the base if necessary and rescan this surface when scanning WTI records.

Clinical No. 2: At the second clinical appointment, the clinician verified the fit of the milled denture during the try-in, as well as the anterior position of the teeth in relation to the patient’s face. Definitive maxillo-mandibular records were established using the preferred philosophy of occlusion with an Aluwax record and index (Figure 7).

Technical No. 2: The WTI records were scanned, creating STL files to export to the AvaDent Design Connect system.

AvaDent No. 2: Once the scans were received and reviewed, they were imported into the centric design file for occlusal record reference. The ridges were then analyzed with this new definitive WTI scan file record. With the new record, digital teeth were arranged and verified in all excursive movements with virtual articulation. After running an occlusion mapping and checking contacts for desired occlusal scheme, the gingival base was built with contoured margins and interdental papillae. The base was also built to verify the desired thickness and replicate the palatal throat form with natural anterior rugae (Figure 8).

Technical No. 3: Once the occlusion was designed and the gingival base built with proper dimensions of peripheral borders, a Digital Design Preview was sent to the customer to preview and manipulate the 3D PDF of the AvaDent Digital Denture Design (Figure 9). At this point, the tooth position in relation to the centric file reference record could be verified, and anterior esthetics and posterior functional occlusion could be checked. When the Design Preview was approved, the files were then exported to AvaDent’s Computer-Aided Machining (CAM) milling process.

AvaDent No. 3: Once the denture is milled, depending on whether the product is fully milled (monolithic) or a bonded complete digital denture, a technician still needs to hand finish and polish the digital denture. The technician verified the digital design with the milled prosthesis while working on each product and reading the case plan of customers’ digital desires and expectations.

Technical No. 4: The finished denture was shipped to the dental laboratory for quality control inspection and billing, and then delivered to the customer.

Clinical No. 3: At the final delivery appointment, the clinician evaluated the dentures for fit, function, esthetic appearance, and patient acceptance (Figure 10).

Conclusion

Digital complete prosthetics workflow processes are evolving rapidly. As these digital workflow processes in removable and implant prosthetics evolve, the advantages to improve communication and collaboration between the clinician and technician become evident. Creating a denture design that is based on the rules of geometry while enabling one to precisely measure, analyze, and visualize prosthetic design images in digital perspectives is a primary factor that differentiates the digital process from traditional ones.

Acknowledgements

The author thanks Stephen Wagner, DDS, for the clinical photos used with this article.

Robert Kreyer, CDT, is the Director of Manufacturing for AvaDent Digital Dental Solutions in Scottsdale, Arizona.

Disclaimer: The statements and opinions contained in the preceding material are not of the editors, publisher, or the Editorial Board of Inside Dental Technology.

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AvaDent Digital Denture Solutions
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855-282-3368

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