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A technique to facilitate the prosthetic rehabilitation of oropharyngeal defects by combining an intraoral scanner with a conventional impression

A technique to facilitate the prosthetic rehabilitation of oropharyngeal defects by combining an intraoral scanner with a conventional impression

A technique to facilitate the prosthetic rehabilitation of oropharyngeal defects by combining an intraoral scanner with a conventional impression

Journal of Prosthetic Dentistry, 2021-07-01, Volume 126, Issue 1, Pages 131-132, Copyright © 2020 Editorial Council for the Journal of Prosthetic Dentistry

Digital techniques for fabricating obturators have been described. However, digital technology is difficult to integrate into their fabrication because of imperfections in the printed casts. In addition, the required equipment or even software-editing expertise may not be available for dentists worldwide. Londono et al recently published a step-by-step technique for fabricating obturator prostheses by using a chairside digital scanner and conventional impressions. However, the demarcation described between the printed cast and the bulb portion, from a conventional impression used to generate a definitive cast, raises some concerns about the complexity of the technique, specifically, whether definitive casts can be combined easily.

In the present article, the authors propose a modification to the technique described by Londono et al with a combination of digital scanning and conventional impressions for only the speech bulb. The modification facilitates the prosthetic rehabilitation of a patient with an oropharyngeal defect and without any need to combine 2 separate casts. The authors believe that the present technique can be used by most prosthodontists with access to an intraoral scanner.

Technique

  • 1.

    Make 2 scans for the maxilla and 1 for the mandible with an intraoral scanner (3Shape Dental System; 3Shape A/S). The first digital scan is limited to the dentition and is highly accurate. In the present example, the first maxillary premolars on the right and left sides, the first and second maxillary molars on the right side, and the second maxillary molar on the left side were prepared for a metal removable framework, and the first maxillary molar on the left side was prepared for a crown. Subsequently, extend the second 3D digital scan image to the posterior pharyngeal wall. This second scan can be performed with a software tool that accelerates the acquisition of images (“insano” tool TRIOS Dental Desktop v1.7.3.2; 3Shape A/S). Such a strategy will facilitate the scan of the oropharyngeal defect and consequently the speech bulb design.

  • 2.

    Combine the two 3D digital scan data sets (3Shape 3D Viewer Setup v1.2.2.0; 3Shape A/S), and print the combination to fabricate the removable metal framework ( Fig. 1 ).

    A, 3D digital scan. B, 3D-printed definitive cast with metal-ceramic crown and metal removable framework.
    Figure 1
    A, 3D digital scan. B, 3D-printed definitive cast with metal-ceramic crown and metal removable framework.

  • 3.

    Verify the fit of the framework, and create an acrylic resin flat base to support the impression material.

  • 4.

    Make an impression with heavy-body (Zetaplus putty; Zhermack) and light-body (Oranwash L light; Zhermack) polyvinyl siloxane impression materials ( Fig. 2 A).

    A, Definitive impression for speech bulb. B, Obturator prosthesis seated.
    Figure 2
    A, Definitive impression for speech bulb. B, Obturator prosthesis seated.

    See Also

  • 5.

    Trim the area of the oropharyngeal defect on the printed cast with a bur (Maxicut PM H79E; Komet) and adapt the framework to it.

  • 6.

    Pour the impression with Type IV dental stone (Fuji Rock; GC America). The definitive cast is ready to wax and process the acrylic resin in the dental laboratory.

  • 7.

    Deliver the prosthesis conventionally ( Fig. 2 B).

References

  • 1. Sun F., Shen X., Zhou N., Gao Y., Guo Y., Yang X., et. al.: A speech bulb prosthesis for a soft palate defect with a polyetherketoneketone (PEKK) framework fabricated by multiple digital techniques: a clinical report. J Prosthet Dent 2020; 124: pp. 495-499.
  • 2. Tasopoulos T., Chatziemmanouil D., Karaiskou G., Kouveliotis G., Wang J., Zoidis P.: Fabrication of a 3D-printed interim obturator prosthesis: a contemporary approach. J Prosthet Dent 2019; 121: pp. 960-963.
  • 3. Palin C.L., Huryn J.M., Golden M., Booth P.R., Randazzo J.D.: Three-dimensional printed definitive cast for a silicone obturator prosthesis: a clinical report. J Prosthet Dent 2019; 121: pp. 353-357.
  • 4. Londono J., Abreu A., Baker P.S., Furness A.R.: Fabrication of a definitive obturator from a 3D cast with a chairside digital scanner for a patient with severe gag reflex: a clinical report. J Prosthet Dent 2015; 114: pp. 735-738.
  • 5. Resende C.C.D., Barbosa T.A.Q., Moura G.F., Tavares L.D.N., Rizzante F.A.P., George F.M., et. al.: Influence of operator experience, scanner type, and scan size on 3D scans. J Prosthet Dent 2021; 125: pp. 294-299.