Digital Removable Complete Denture—an Overview.pptx

There is a great responsibility for a dentist and a dental technologist to fabricate high-quality removable complete
dentures. Factors, such as a meticulous diagnosis and treatment planning, a personal communication between the
involved persons, and a profound knowledge of the clinical and technical possibilities, should lead to an easy, simple,
cost-effective, and highly satisfying denture fabrication workflow.

1. Digital Removable Complete Denture—an Overview Nishu Priya 3 rd year PGT Journal club

2. Definition and History According to the Glossary of Digital Terms, a digital denture is a complete denture created by or through automation using CAD (computer-aided designing), CAM (computer-aided manufacturing), and CAE (computer-aided engineering) in lieu of traditional processes. In 2010, Kim found One Denture, which was one of the first companies to offer a clinical computer aided design and computer aided manufacturing (CAD/CAM) workflow for fabricating removable complete dentures. In 2016, Tae Kim was the first to offer a definitive printed denture from Dentca (Dentures from California) ( Dentca , Torrance, CA), a company that evolved from One Denture. 3

3. CAD/CAM vs conventional Goodacre et al demonstrated that CAD/CAM fabrication techniques using a milling process produced the most overall accurate and reproducible intaglio surface when compared to pack and press, pour and injection base processing techniques. Al- Helal et al then compared the retention between maxillary milled and conventionally fabricated denture bases in an in vivo study and concluded that the retention produced by milled pre-polymerized PMMA complete dentures bases was significantly higher than that of conventional heat polymerized PMMA denture bases.

4. ADDITIVE AND SUBTRACTIVE MANUFACTURING Additive techniques can produce objects whose geometry cannot be produced on a mill. less post fabrication waste the equipment required to produce a printed denture can cost less than mills which makes it affordable to smaller laboratories. Additive In printed dentures, non-polymerized photosensitive liquid resin can potentially cause a negative mucosa (patient) and/or skin (technologist) reaction

5. Advantages Difficult to assess proper jaw relation Must use dimensionally and temperature-resistant impression materials such as PVS more expensive laboratory fee Presence of initial learning curve Scarcer data and experiences compared to conventional fabrication technique Disadvantages 6 Fewer visits, less chair time Milled denture bases are stronger than conventionally processed denture bases Less porosity Fewer chances of microorganism contamination Easier to achieve proper occlusion. Better fitting Potentially less follow-up adjustments Ease of replicating duplicate dentures

6. Denture teeth The advantages attributed to the prefabricated teeth are high esthetics and low wear characteristics, but the shapes are limited and predetermined. Recently, prefabricated denture teeth specifically designed for printed bases have been introduced (Dentsply Sirona). These teeth are designed with a reduced tissue surface that allows for placement in predetermined sockets in the printed base. This is an advantage since denture teeth that invade the intaglio of a printed denture base cannot be easily removed using current fabrication techniques.

7. 8 The chief disadvantage of milled teeth are their lack of esthetics as compared to prefabricated multilayer denture teeth. Printed denture teeth can be made using the same technology as the printed base. Several companies now supply resin specifically designed for tooth production ( Dentca , NextDent B.V., Soesterberg , the Netherlands) and their use has become increasingly popular due to ease of production in a small dental lab or dental office. Although the wear characteristics of printed teeth are often cited as a disadvantage, studies have shown that these teeth provide adequate wear resistance for clinical use.

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10. Technical Properties A higher flexural strength, fracture toughness, and modulus of elasticity  the fabrication of a thinner denture base. A higher surface hardness  a less vulnerable surface. Better surface properties (smoother surface texture, more hydrophilic, better wettability), depending on the quality of the milling path and on the milling tools used  denture surfaces less attractive to microbial colonization. After polishing, milled specimens showed superior surface characteristics than 3D printed and conventionally produced specimens . A reduced monomer content for industrially produced PMMA pucks, and a similar monomer release of CAD-CAM dentures compared to heat-polymerized dentures . A better denture base adaptation and reproducibility were detected (superimposition of STL files) for CAD-CAM milled dentures compared to conventional. A higher overall accuracy of the denture base for the milled, over the 3D printed, and over the conventionally fabricated denture base for both maxillary and mandibular arches was recently reported.

11. 12 Clinical Properties 1. A similar biocompatibility between a CAD-CAM PMMA and a conventionally heat-polymerized PMMA was found in vitro in a cell culture. 2. A better denture retention mainly due to the absence of polymerization shrinkage was observed for milled dentures compared to conventional dentures. 3. A reduced affinity for adhesion of Candida albicans on a CAD-CAM denture base than to a conventional base  decrease of the incidence of denture stomatitis is postulated.

12. Clinical workflow None of the workflows that are currently being promoted by the dental industry incorporate a facebow or will allow the technician to design a prosthesis with traditional balanced occlusion. Many manufacturers offer digitally manufactured trial dentures that allow the clinician to determine and evaluate tooth position, occlusal vertical dimension, centric relation, the position of the occlusal lane and fit at the second clinical appointment. An example of a monolithic trial denture Amodified monolithic trial denture with the addition of denture teeth in wax.

13. Comparison of conventional and digital workflow

14. Impression making, Determination of Vertical and Horizontal Dimension, and Try‑in The aim of impression taking of an edentulous jaw is to reproduce the mucosal denture bearing area—a viscoelastic soft tissue—in a healthy state without pressure, and to ensure a perfect inner and outer peripheral seal at the denture border area, leading as a consequence to support, stability, and retention of the denture base. According to Lo Russo et al., intraoral scanners take a mucostatic impression of the edentulous arch. They cannot yet replicate functional movements. The combination of a conventional impression with an intraoral scan has been described for pressureless impression taking of flabby tissue . Hereby, the flabby tissue is scanned through a window in the impression tray, whereas the stable tissues are replicated by a conventional impression. The two impression datasets are then superimposed.

15. Custom Tray Impression and Wax Rim Base IOR Technique involves try-in and adjustment of the custom tray border molding with suitable materials, such as modeling compound or a heavy body PVS (i.e., putty) followed by initial and final wash impressions with either a light, medium, and/or heavy body PVS. Conventional wax rim evaluations and adjustments IOR is then recorded using the wax rims and PVS occlusal registration material. Replication Technique by Copying Existing RCDs Check denture overextensions, and adjust them before border molding. wash impression would be made using a light, medium, or heavy body PVS material. Afterwards, an IOR with PVS is taken. Impression scans and IOR scan would be Scans merged using the best-fit procedure for relating the impression scans and the IOR scan.

16. Denture Delivery, Maintenance, and Denture Hygiene At the time of delivery of the removable complete denture, the following aspects are checked with the help of a spot indicator paste: the extension of the denture flanges, the lip and cheek support the internal peripheral seal, the presence of pressure spots with an articulating paper the occlusion in static and dynamic.

17. Conclusions and Future Aspects There is a great responsibility for a dentist and a dental technologist to fabricate high-quality removable complete dentures. Factors, such as a meticulous diagnosis and treatment planning, a personal communication between the involved persons, and a profound knowledge of the clinical and technical possibilities, should lead to an easy, simple, cost-effective, and highly satisfying denture fabrication workflow.

18. This case report demonstrates a repeatable workflow using a digitally replicated denture (DRD), which capitalizes on the benefits of digitally fabricated dentures. A 75-year-old man in good health presented with existing maxillary and mandibular complete dentures that he had worn for over 15 years. The mandibular prosthesis had a soft reline that had become brittle and uncomfortable. He was generally satisfied with the fit and appearance of his maxillary denture, but was interested in a slightly “tighter fit.” After reviewing treatment options, the patient elected to have a new set of complete dentures fabricated.

19. 20 The maxillary and mandibular complete dentures were scanned using an intraoral scanner. This scan generated these STL files, which could be sent to a variety of places: a design software program, a dental laboratory, or as in this case, directly to a 3D printer The printed STL files (in the bottom of the photo) are a dimensionally accurate duplicate of the patient's scanned existing dentures

20. To achieve a better fit than the existing dentures, the DRD was used as a custom tray. PVS tray adhesive was painted on the intaglio of both upper and lower. The lower was border molded with heavy body PVS before a light body impression was made. The upper (pictured here) required only a light body (“wash”) impression, as the denture was relatively well-adapted After upper and lower impressions were made it the DRDs, they were much more stable. With these in place, the patient was guided into centric relation, and the position was recorded with a bite registration PVS ( Regisil , Dentsply, York, Pennsylvania). The pictured impressions and bite were sent to the dental laboratory A frontal, full face digital photo was taken and sent to the laboratory for smile design

21. 22 The photo was uploaded into design software (3shape, Copenhagen, Denmark). An STL file of the DRD (shown here in purple) was matched to the full face photo using common points (incisal edges, etc )

22. 23 A digital set-up was then completed based on the patient's requests and facial features. In this photo, the proposed smile design is in white, overlaying the patient's existing denture (DRD in blue). Having the proposed changes overlaying the existing allows the differences to be visualized easily by altering the transparency

23. 24 The proposed set-up, allowing the patient and provider to approve set-up before the try-in visit Digital preview of tooth set-up, based on smile design. This file can be 3D printed, and ultimately used to fabricate the CAD/CAM denture Like a conventional wax try-in, the printed trial denture allows the patient to visualize esthetics, phonetics, and function

24. 25 Unlike a conventional set-up on a light-cure base, the denture bases (including flanges and extensions) replicate the final denture borders. This allows the patient and provider to accurately evaluate fit and retention at the try-in appointment as well (similar to a conventional processed record base) The pictured dentures are monolithic PMMA — the teeth and bases are one piece, milled from the same puck. Pink composite was hand layered on the cameo surface for esthetics The seated definitive maxillary and mandibular dentures

25. Discussion Many patients are very comfortable with the fit and/or esthetics of their existing dentures. Some would truly just like a duplicate to use as a back-up in case they lose or break their dentures. The protocol followed in this case report demonstrates an easy and predictable way to assist these patients. In addition, the laboratory now has a digital file (STL) of the new dentures, so these can be replicated at any time for any reason without additional patient visits. There are multiple workflows available for digital dentures, allowing clinicians to individualize treatment for their patients. This also allows clinicians to maintain conventional techniques for whichever steps they prefer.

26. This article describes the rehabilitation of 15 edentulous older adults, five females and ten males, in the age range of 61–79 years with an average of 67.7 years. Among the patients, 12 of them were previous denture wearers, who were dissatisfied with their current prosthesis. Due to the time constraints and a favorable ridge relationship, a CAD‑CAM complete denture was planned for the patients using the Baltic Denture System after obtaining informed consent from them.

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28. Tissue stops incorporated in the upper key Using BD Key® plane and Fin for orientation occlusal plane Tissue stops incorporated in the lower key. (b) Making mandibular final impression using polyvinyl siloxane

29. The maxillary final impression using polyvinyl siloxane Completed impressions with key set bite registration. Extraoral scanning of the impressions and bite registration

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31. Milling the computer‑aided design/computer‑aided manufacturing denture using a 5‑axis milling machine. Final prosthesis post insertion and adjustment

32. Compared to conventional dentures, CAD‑CAM dentures have been found to have reduced resin volume and weight, which can increase patients’ comfort and adaptability. These dentures release little monomer; however, it has not been found to be statistically significant when compared to longtime, water bath, heat‑polymerized dentures fabricated conventionally. The biggest advantage of the Baltic Denture System is the reduced clinical visits, which is appealing to both the clinician (especially those with a higher throughput rate) and patients alike. The denture delivery is ensured at the second visit in comparison with other CAD‑CAM systems currently available. However, the inability to digitally customize the dentures and accurately verify centric relation is one of the drawbacks. This denture system is presently applicable only to patients with a favorable Class I maxillomandibular relationship, which is another limitation when compared with conventional techniques. Discussion

33. Conclusions There is a great responsibility for a dentist and a dental technologist to fabricate high-quality removable complete dentures. Factors, such as a meticulous diagnosis and treatment planning, a personal communication between the involved persons, and a profound knowledge of the clinical and technical possibilities, should lead to an easy, simple, cost-effective, and highly satisfying denture fabrication workflow. Understanding the concept that there is more than one workflow and that digital and conventional protocols can be combined may eliminate barriers for those that are hesitant to try a digital protocol. However, there is a scope for extensive research, backed by long‑term clinical studies in this relatively new technology, CAD‑CAM dentures are here to stay!

34. References 35 Clark, W. A., Duqum , I., & Kowalski, B. J. (2018). The digitally replicated denture technique: A case report. Journal of Esthetic and Restorative Dentistry. doi:10.1111/jerd.12447  Hirayama, H. (2019). Digital Removable Complete Denture (DRCD). Digital Restorative Dentistry, 115–136. doi:10.1007/978-3-030-15974-0_6 Wagner, S. A., & Kreyer , R. (2021). Digitally Fabricated Removable Complete Denture Clinical Workflows using Additive Manufacturing Techniques. Journal of Prosthodontics, 30(S2), 133–138. doi:10.1111/jopr.13318 Fang JH, An X, Jeong SM, Choi BH. Development of complete dentures based on digital intraoral impressions—case report. journal of prosthodontic research. 2018 Jan 1;62(1):116-20.