|Ahead of print publication
Combination intraoral radiation mouthguard-positioning stent
Zain Uddin Ahmed1, Joseph D Randazzo1, Joseph M Huryn1, Evan B Rosen2
1 Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
2 Dental Oncology and Maxillofacial Prosthetics, Miami Cancer Institute, Miami, FL, USA
|Date of Submission||03-Oct-2019|
|Date of Decision||12-Jan-2020|
|Date of Acceptance||22-Apr-2020|
|Date of Web Publication||10-May-2021|
Evan B Rosen,
Dental Oncology and Maxillofacial Prosthetics, Miami Cancer Institute, Miami, FL
Source of Support: None, Conflict of Interest: None
The sequelae of head-and-neck radiation may include hyposalivation, dysgeusia, trismus, mucositis, and osteoradionecrosis. A mouthguard used during radiation therapy can mitigate the effects of backscatter radiation from dental restorations. In addition, an intraoral positioning stent can assist in repositioning oral structures, such as the tongue, away from the field of radiation during treatment, thereby limiting dose delivery. The purpose of this article is to provide a technique to fabricate a combination prosthesis, which functions to reposition oral structures as well as mitigate the effects of backscatter from dental restorations during head-and-neck radiation therapy.
Keywords: Dental oncology, intensity-modulated radiation therapy, mouthguard, radiation therapy, tongue-displacing prosthesis
| > Introduction|| |
Radiation therapy, a frequently used modality for the treatment of head-and-neck cancer patients, can cause treatment-related effects to the adjacent tissues when the therapeutic dose exceeds the tolerance volume of the surrounding tissue. The sequelae of treatment may include hyposalivation, dysgeusia, trismus, dermatitis, nutritional stomatitis, mucositis, and osteoradionecrosis. Such sequelae of treatment can adversely affect patient's quality of life.,,, Moreover, dental restorations with high atomic weight can enhance radiation dose by more than 50% on the adjacent tissues, further enhancing the effect of radiation on adjacent structures in the head-and-neck regions., Radiation mouthguards have been recommended to mitigate this during treatment. However, mouthguards are limited in that they provide a spacer over the dentition and do not reposition oral structures (i.e., intermediary structures such as submandibular glands, or pharyngeal muscles). Limiting radiotherapy to oral structures not requiring treatment can mitigate treatment-related functional deficiencies following therapy. To conventionally achieve this effect, foreign objects are placed in the oral cavity to displace the tongue, or stents are fabricated for the displacement of intraoral tissues. This process is not always pragmatic and can be inconvenient for the patient and the provider. To overcome such challenges, a combination radiation mouthguard prosthesis that also functions as a tongue-displacing stent is fabricated. The purpose of this report is to provide a technique to fabricate this prosthesis, which could be used to displace the tongue from the radiation field during head-and-neck radiation therapy.
| > Prosthesis Fabrication Technique|| |
To begin the fabrication procedure, maxillary and mandibular impressions are made with irreversible hydrocolloid material (Jeltrate Plus; Dentsply Sirona, York, PA, USA). A mandibular cast is poured using dental stone (Type III, Denstone, Modern Materials; Kulzer, LLC, South Bend, IN, USA), and an acrylic-processed base (Lucitone 199; Dentsply Sirona, York, PA, USA) is fabricated using a wrought wire and ball clasps for retention. The acrylic-processed base is tried in and checked for adequate retention in the oral cavity. Then, green stick impression compound (Type I, Kerr SpofaDental, Jicin, Czech Republic) is placed on the cameo surface of the prosthesis [Figure 1] and molded intraorally to permit tongue displacement away from the treatment area that can be tolerated by the patient. The prosthesis is then laboratory processed into acrylic resin (Lucitone 199; Dentsply Sirona, York, PA, USA) [Figure 2]. A thermoplastic material (Ethylene Vinyl Copolymer, Soft Eva, Henry Schein INC, Melville, NY, USA) is then placed over the prosthesis on a cast of the patient's dentition with the use of a vacuum former (Sta-Vac™, Buffalo Dental Manufacturing Co. Inc., Syosset, NY, USA) for 2–3 min under the pressure of 60 psi and about 250°F. The cast with prosthesis is removed from the vacuum former and excess material is removed following cooling of the prosthesis. The prosthesis is cleaned and polished prior to prosthesis delivery. The complex radiation treatment device is then tried in and adjusted to patient's satisfaction [Figure 3] and [Figure 4]. The ability to place and remove the prosthesis is demonstrated by the patient. The patient is counseled to wear the device to the radiation therapy simulation as well as radiation therapy treatment appointments to achieve the desired effect.
|Figure 3: Intraoral view of the patient with the radiation stent in place|
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|Figure 4: Intraoral view of the patient with radiation stent displacing the tongue|
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| > Discussion|| |
The advances in radiation therapy delivery have reduced radiation delivery dose to organs at risk, but in the oral cavity, dose reduction has remained as a consistent problem due to the proximity of intraoral structures.,,,,,, Strategies for limiting radiation dose to normal tissues in the oral cavity can be achieved by shielding or repositioning. Patients treated for tumors in the parotid, retromolar trigone, floor of the mouth, or tonsillar regions may be candidates for a combination intraoral radiation mouthguard-positioning stent. The advantage of the combination intraoral radiation mouthguard-positioning stent is that the clinician can complete fabrication of the prosthesis with limited chair time. There is also no requirement for any special prosthodontic proficiency, laboratory procedures, or expensive equipment. This technique requires materials which are usually available in a dental office, as well as expertise possessed by a general dentist. Furthermore, the patient only requires a single prosthesis (instead of multiple bite blocks or stents) which enables repeatable tongue-and-mouth positioning during treatment. Successful use of this prosthesis requires an interdisciplinary collaboration between the radiation oncology and dental teams. A limitation of this technique may include lack of access to dental providers for stent fabrication. Future directives include the use of digital technology for stent fabrication, radiation dose contouring to quantify oral cavity dose distribution with the intraoral stent, and the use of patient-reported outcomes to better quantify the value of prosthesis use during treatment.
| > Conclusion|| |
This article outlines a technique to fabricate a combination intraoral radiation mouthguard-positioning stent for use during head-and-neck radiotherapy. Use of this prosthesis may improve patient care by protecting normal tissues of the oral cavity from receiving the backscattered radiation and displacing the tongue from the field of radiation.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his/her consent for his/her images and other clinical information to be reported in the journal. The patient understands that his/her name and initial will not be published, and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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