A direct technique to fabricate an intraoral shield for unilateral head and neck radiation Zafrulla Khan, DDS, MSa and Tamer Abdel-Azim, DDSb University of Louisville, Louisville, Ky A radiation oncologist may ask the prosthodontist to fabricate an intraoral shield when ipsilateral fields are used for patients with head and neck cancer. A technique for its fabrication is described that can be accomplished with materials and equipment that are readily available in the dental office. Baseplate wax is used intraorally to fabricate a pattern, which is duplicated with irreversible hydrocolloid material. Autopolymerizing acrylic resin is then used to make the shield. This simple technique can be completed in a single visit. (J Prosthet Dent 2014;-:---) Patients with head and neck cancer are often treated with radiotherapy as a primary modality. Tumor treatments may include radiotherapy alone, adjuvant to surgery, in conjunction with chemotherapy, or a combination of those. Radiotherapy is also used as a palliative treatment for late-stage and unresectable head and neck cancers.1-3 For head and neck radiation, the single most important consideration is to deliver the maximum radiation dose to the tumor while keeping the dose to the surrounding normal structures to a minimum level. Depending on the diagnosis, radiation is delivered to the primary tumor, the surgical site, and the lymph nodes in the neck. The goal of radiotherapy is to eradicate malignant tumor cells without causing significant damage to the healthy tissues. In head and neck cancers, because of location, the radiation fields usually involve the salivary glands. This can cause salivary dysfunction, causing dry mouth (xerostomia) and resulting in alterations in speech and taste, difficulty with mastication and swallowing, mucositis, dental caries, or infections.4 If the primary tumor is localized to the tonsillar region, tongue, gingiva, or other oral tissues without the involvement of midline structures, ipsilateral radiation may be used to reduce the morbidity of contralateral normal

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tissues5 by excluding the opposite salivary glands and the oral cavity mucosa. In patients for whom ipsilateral head and neck radiation is used, normal tissue reactions can be minimized with the use of simple, custommade intraoral stents designed to exclude uninvolved tissues from the treatment radiation ports and shield tissues within the treatment fields. Shielding stents with a lead alloy are beneficial when treating well-lateralized tumors of the oral cavity, parotid glands, lip, and cheek. The radiation oncologist determines the need for a radiation stent. The prosthodontist/dentist can help fabricate the stents to meet specific patient and treatment needs, thereby limiting complications during and after radiation therapy. Radiation stents are commonly fabricated from acrylic resin with or without shielding alloy, depending on the requirements of the individual patient. Conventional prosthetic techniques used to fabricate these stents require many steps (including maxillary and mandibular impressions, casts, articulations, investing, and processing.) This article describes a simple, chairside technique for fabricating an intraoral radiotherapy shield, eliminating these steps. Such a technique saves time, increases patient comfort,

Professor, Dental Oncology, James Graham Brown Cancer Center. Assistant Professor, Department of Oral Health and Rehabilitation, School of Dentistry.

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and decreases the number of appointments so the patient can begin radiation treatment.

TECHNIQUE 1. Soften a sheet of Type II base plate wax (True wax; Dentsply Intl) in an electrically controlled water bath at 37 C (Fig. 1). 2. Roll the softened wax sheet, contour according to the arch form, and position it between the teeth and tongue in the patient’s mouth. While the wax is still soft, mold the wax to form the direct wax pattern of the shield and make an interocclusal record simultaneously (Figs. 2, 3). 3. Prepare a mold of the wax pattern immediately (to minimize distortion) with irreversible hydrocolloid material (Jeltrate Fast Set; Dentsply Caulk) (Fig. 4). 4. Mix autopolymerizing resin (Dentsply Caulk) according to the manufacturer’s instructions and pour it into the prepared mold space. This procedure eliminates investing and heat processing (Figs 5, 6). 5. After the initial set, allow the resin shield to polymerize in a warm water bath in a pressure vessel for 30 minutes. Adjust the acrylic resin (Dentsply Caulk) shield as needed (Fig. 7).

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1 Base plate wax is softened in hot water bath.

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2 Manual manipulation of wax extraorally.

3 Intraoral molding of wax and simultaneous interocclusal 4 Irreversible hydrocolloid mold of completed wax pattern. record.

5 Pouring autopolymerizing resin into prepared mold. 6. Cut a lead sheet (MarShield, 3.18 mm; MarShield) according to the shape of the resin pattern. Attach the lead sheet to the resin pattern with additional autopolymerizing resin to complete the shield (Fig. 8).

6 Separation of autopolymerizing resin from mold.

SUMMARY This technique has many advantages. It uses dental materials that are readily available in the dental office and is easy to use without extensive

The Journal of Prosthetic Dentistry

prosthetic expertise. This technique minimizes clinical and laboratory times, as most of the steps of conventional techniques are eliminated, making it cost effective and efficient. The shield is made of autopolymerizing resin, as this

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7 Finished autopolymerizing resin shield.

material does not interfere with radiation and can be easily fitted and modified as necessary. The stent is easy for patients to clean and handle.

REFERENCES 1. Ang KK, Garden AS. Radiotherapy for head and neck cancers: indication and techniques. 4th ed.Philadelphia: Lippincott Williams & Wilkins; 2011. p. 1-56. 2. Mendenhall WM, Riggs CE, Amdur RJ, Hinerman RW, Villaret DB. Altered fractionation and/or adjuvant chemotherapy in definitive irradiation of squamous cell carcinoma of the head and neck. Laryngoscope 2003;113:546-51.

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8 Intraoral view of shield.

3. Cooper JS, Pajak TF, Fovastieve AA, Jacobs J, Campbell BH, Saxman SB, et al. Postoperative concurrent radiotherapy and chemotherapy for high-risk squamous cell carcinoma of the head and neck. N Engl J Med 2004;350: 1937-44. 4. Chambers MS, Tooth BB, Martin JW, Fleming TJ, Lemon JC. Oral and dental management of cancer patient: prevention and treatment of complications. Support Care Cancer 1995;3:168-75. 5. Jensen K, Overgaard M, Grau C. Morbidity after ipsilateral radiotherapy for oropharyngeal cancer. Radiother Oncol 2007;85:90-7.

Corresponding author: Dr Zafrulla Khan University of Louisville School of Dentistry 501 S Preston St, Room 312 Louisville, KY 40202 E-mail: [email protected] Copyright ª 2014 by the Editorial Council for The Journal of Prosthetic Dentistry.