A Single-Visit Solution by Dr. Nadim Z. Baba

Categories: Prosthodontics;
A Single-Visit Solution 

Digital dentures in a few hours offer a safer option for a patient who can’t risk visiting the practice several times


by Dr. Nadim Z. Baba


Seniors living in long-term assisted-living care facilities and nursing homes are a particularly vulnerable population when it comes to receiving proper oral care.1 The aging population in the United States is living longer2 and retaining more of their natural teeth than previous generations.3 As these seniors transition from independent to dependent living, their oral needs often go unaddressed, resulting in tooth loss, poor oral hygiene and oral disease.4 Good oral health significantly affects general health, especially in older adults, because the ability to chew and consume food affects the quality of their diet and, as a consequence, their overall health. The oral health of residents in long-term care facilities is often not perceived as a priority by caretakers, which delays assessment and treatment.4

In recent years, the ability to properly treat geriatric adults has been exacerbated by the pandemic, because this older population is more susceptible to infection and compromised by existing age-associated health conditions.5 For this most vulnerable patient demographic, treatments that require multiple appointments and long appointment times increase the risk of COVID-19 infection for both the patient and the dental care professional. Treatment options that limit the number of in-practice visits are optimal for treating these patients.


Clinical report

A 94-year-old patient who lives in a long-term assisted-living facility with his wife was referred to the practice by his daughter, a longtime patient of the dental practice. The chief complaint was that he had difficulty eating because of the degradation of his teeth. The daughter requested her father be fitted with dentures to restore his chewing ability, aesthetics and self-esteem, but she also wanted a solution that did not require multiple practice visits, because taking him from the assisted-living facility was a difficult process and increased his chances of exposure to the coronavirus.

Because of the patient’s age and vulnerability if exposed to COVID-19, he was scheduled for a Saturday appointment, when no other patients or staff would be present. Upon initial examination, it was obvious he had been mostly edentulous for many years: The mandibular arch was edentulous and only four tooth roots remained in the maxillary arch (Fig. 1). The treatment plan that would best fit this patient with a long-term and aesthetic solution without multiple visits to the practice was an immediate CAD/CAM-milled monolithic denture.

Digital-Dentures
Fig. 1

Several methods can be used to obtain clinical records for the digital denture workflow. Because this patient presented with no existing dentures, it was decided to use conventional definitive impressions to accurately capture his anatomy and muscles that would be involved in holding a denture in his mouth.

Appropriately sized heat-moldable disposable impression trays (Accudent XD, Ivoclar, Fig. 2) were used to make the definitive maxillary and mandibular impressions. Adhesive was applied to the flanges of the maxillary impression tray before border molding, using heavy-body polyvinyl siloxane, or PVS (Virtual XD Heavy Body, Ivoclar, Figs. 3 and 4). Once the border molding procedure was completed, additional adhesive material was painted on the remaining parts of the tray and a definitive impression was made a using light-body wash PVS impression material (Virtual XD Light Body, Fig. 5). The impression-taking protocol was repeated for the mandibular arch (Figs. 6–8).
Digital-Dentures
Fig. 2
Digital-Dentures
Fig. 3
Digital-Dentures
Fig. 4
Digital-Dentures
Fig. 5
Digital-Dentures
Fig. 6
Digital-Dentures
Fig. 7
Digital-Dentures
Fig. 8


Condensing the timeline

At this point in the record-taking process, clinicians would normally send the impressions to the laboratory to pour working casts and fabricate wax rims, which would be “tried in” at the patient’s second visit to verify phonetics, aesthetics, occlusal vertical dimension (OVD), occlusion and retention. Because of the unique nature of this case, I chose to complete these steps in the office while the patient was waiting.

Maxillary and mandibular stone casts and wax rims were created using conventional protocols (Fig. 9). The wax rims were inserted into the patient’s mouth to perform any needed corrections to the midline, position of the teeth, centric relation (CR) or OVD. A bite registration (Virtual CADBite, Ivoclar) was completed to record the relationship between the maxilla and mandible (Fig. 10) and to provide information that would be critical for initial placement of the denture teeth—incisal length, labial position and occlusal plane, as well as vertical dimension and centric occlusion.
Digital-Dentures
Fig. 9
Digital-Dentures
Fig. 10

In a conventional case, the dentist would send the bite registration to the lab for design of the denture teeth and request 3D-printed try-in dentures, which would help ensure the midline was correct and the patient approved of the aesthetics and phonetics of the planned prostheses before the laboratory milled the final dentures. It must be noted that in this scenario, depending on the degree of changes needed for an optimal fit, the technology to print multiple try-in dentures is not cost-prohibitive and makes the option of multiple try-in dentures feasible.

Because this case was unique in that the final prosthetic had to be completed in a single visit, the maxillary and mandibular definitive casts as well as the labial/buccal surfaces of the wax rim bite registration were scanned in the in-house laboratory and the scans uploaded into the CAD software program (Fig. 11) for virtual articulation of the wax rims (3Shape Ivotion, 3Shape), virtual setup of the denture teeth and CAD design of the complete dentures (Figs. 12–14).

Digital-Dentures
Fig. 11
Digital-Dentures
Fig. 12
Digital-Dentures
Fig. 13
Digital-Dentures
Fig. 14


Milling the definitive prostheses

The subtractive manufacturing digital denture system used for this case (Ivotion, Ivoclar) offers two types of definitive complete- denture protocols.

One protocol is a denture base milled from a prepolymerized block of polymethyl methacrylate (Ivobase CAD, Ivoclar) along with milled denture teeth from a block of dual cross-linked material (SR Vivodent CAD, Ivoclar). The milled denture teeth are then bonded into the milled recesses using a special PMMA bond material (Ivobase CAD Bond, Ivoclar). The dentures are then finished and polished and sent to the prescribing dentist for placement.

The second protocol is a monolithic denture milled from a bicolor disk (Ivotion). One half of the disc is the denture base material made of high-impact optimized PMMA while the other half is the tooth material made of highly cross-linked PMMA with no filler (Fig. 15). After the virtual design of the dentures on the CAD software (3Shape), the bicolor disk is milled through a single, uninterrupted milling process, then finished, polished and sent to the prescribing dentist for placement.
Digital-Dentures
Fig. 15

For this patient, a milled prosthetic option that did not require manually bonding the milled denture teeth to the base was chosen. The unique geometry of the bicolor milling disc allows for a single milling process (PrograMill PM7, Ivoclar) to produce a definitive monolithic denture (Fig. 16). The economic advantages include having to use only one disc, uninterrupted milling procedure, less milling time overall and fewer chairside adjustments. In addition, the strength of the denture is enhanced because the homogeneous chemical fusion of the teeth and base materials are uniquely processed without a bonding interface; therefore, the dentures are physically monolithic, producing dimensionally accurate final dentures with high-quality aesthetics that require only minimal clean-up and finishing.

Digital-Dentures
Fig. 16


Definitive denture placement

While the dentures were being milled, the patient’s four remaining tooth roots were extracted. Once the milling process was completed, the final dentures were manually polished (Fig. 17) and inserted into the patient’s mouth (Figs. 18 and 19).
Digital-Dentures
Fig. 17
Digital-Dentures
Fig. 18
Digital-Dentures
Fig .19

The placement and postplacement adjustments of CAD/CAM-created complete dentures are similar to the placement of conventional dentures; however, the degree of adjustment required to insert digitally processed dentures and the follow-up postinsertion appointments are significantly minimized, compared with traditional clinical workflow and manufacturing.6 Traditional procedures and materials (Fit Checker, GC America) or pressure-indicating paste (PIP, Keystone Industries) are suggested to identify and adjust the fit of the intaglio surfaces of the dentures to the intraoral mucosa. For this case, occlusal contacts were verified and adjustments made intraorally. If considered needed, a clinical remount procedure can be performed depending on the degree of occlusal adjustment required.


Conclusion

Although this unique case required in-practice completion of the digitally manufactured case, all of the steps leading up to the milling process and final delivery are conventional protocols that dentists would normally complete for denture processing.

Digital dentures offer clinicians many advantages over conventionally fabricated dentures.7,8 Among them:
  • The ability to efficiently and effectively treat patients who have difficulty commuting to the practice for multiple appointments.
  • The ability to record clinical information (impressions, interocclusal records, and tooth selection) in a single, one- to two-hour appointment, depending on the clinician’s experience.
  • The ability to place and seat the dentures in the second appointment.
  • The ability to reduce clinical chair time, which is more cost effective and decreases practice overhead.
  • The ability to archive digitally obtained 3D images and record-taking data in the event the patient should need a replacement denture.
  • And the prepolymerized acrylic resin used for the fabrication of the denture base provides a superior fit and strength compared with conventionally processed bases.

Learn more about dentures for older patients
and earn CE credit
Dr. Arnold Liebman’s online CE course explains how to make aesthetic dentures for older patients even if they have medical issues, no lower ridge or other challenges. To take the course for a chance to earn 1.5 CE credits, click here.

References
1. Porter, J., Ntouva, A., Read, A., Murdoch, M., Ola, D., and Tsakos, G. “The Impact of Oral Health on the Quality of Life of Nursing Home Residents.” Health Qual Life Outcomes. 2015;13:102.
2. Medina, Lauren, Sabo, Shannon, and Vespa, Jonathan. “Living Longer: Historical and Projected Life Expectancy in the United States, 1960 to 2060 Population Estimates and Projections.” U.S. Census Bureau, US Department of Commerce. https://www.census.gov/library/publications/2020/ demo/p25-1145.html, accessed Feb. 7, 2022.
3. CDC. Public Health and Aging: Retention of Natural Teeth Among Older Adults—United States, 2002. https://www. cdc.gov/mmwr/preview/mmwrhtml/mm5250a3.htm, accessed Feb. 7, 2022
4. Badewy, Rana, Singh,Kharkirat, Quinone, Carlos, and Singhal, Sonica. “Impact of Poor Oral Health on Community- Dwelling Seniors: A Scoping Review.” Health Service Insights, Vol. 14: 1–19. Accessed Feb. 7, 2022.
5. CDC. COVID-19 Risks and Vaccine Information for Older Adults. www.cdc.gov. Accessed Feb. 7, 2022.
6. Smith, P.B., Perry, J., and Elza, W. “Economic and Clinical Impact of Digitally Produced Dentures.” J Prosthodont 2021;30(S2):108–112.
7. Janeva, N.M., Kovacevska, G., Elencevski, S., Panchevska, S., Mijoska, A., and Lazarevska, B. “Advantages of CAD/ CAM Versus Conventional Complete Dentures—A Review.” Open Access Maced J Med Sci. 2018 Aug 4;6(8):1498–1502.
8. Baba, N.Z., Goodacre, B.J., Goodacre, C.J., Müller, F., and Wagner, S. “CAD/CAM Complete Denture Systems and Physical Properties: A Review of the Literature.” J Prosthodont 2021;30(S2):113-–124.


Author Bio
Dr. Nadim Baba
Dr. Nadim Z. Baba received his DMD from the Université de Montréal in 1996, completed a certificate in advanced graduate studies in prosthodontics, and earned a master’s degree in restorative sciences in prosthodontics from the Boston University School of Dentistry in 1999.

Baba is a professor in the advanced education program in implant dentistry at Loma Linda University School of Dentistry, an adjunct professor at the University of Texas Health Science Center School of Dentistry in the comprehensive dentistry department, and maintains a part-time private practice in Glendale and Long Beach, California. He is the past president of the American College of Prosthodontists (ACP), a diplomate of the American Board of Prosthodontics and a fellow of the ACP and the Academy of Prosthodontics.

The author of numerous articles and an international lecturer, Baba also has published the book "Contemporary Restoration of Endodontically Treated Teeth: Evidence-Based Diagnosis and Treatment Planning."
 

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