|Year : 2016 | Volume
| Issue : 2 | Page : 1102-1103
Cerrobend shielding stents for buccal carcinoma patients
Karma Yangchen, Saumyendra Vikram Singh, Himanshi Aggarwal, Raghuwar Dayal Singh, Ramashanker Siddharth, Niraj Mishra, Shuchi Tripathi
Department of Prosthodontics, Faculty of Dental Sciences, King George's Medical University, Lucknow, Uttar Pradesh, India
|Date of Web Publication||25-Jul-2016|
Department of Prosthodontics, Room No. 404 E, Gautam Buddha Hostel, Chowk, Lucknow - 226 003, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Buccal carcinoma is one of the most common oral malignant neoplasms, especially in the South Asian region. Radiotherapy, which plays a significant role in the treatment of this carcinoma, has severe adverse effects. Different types of prosthesis may be constructed to protect healthy tissues from the adverse effects of treatment and concentrate radiation in the region of the tumor mass. However, the technique for fabrication of shielding stent with Lipowitz's alloy (cerrobend/Wood's alloy) has not been well documented. This article describes detailed technique for fabrication of such a stent for unilateral buccal carcinoma patients to spare the unaffected oral cavity from potential harmful effects associated with radiotherapy.
Keywords: Buccal carcinoma, radiotherapy, stent
|How to cite this article:|
Yangchen K, Singh SV, Aggarwal H, Singh RD, Siddharth R, Mishra N, Tripathi S. Cerrobend shielding stents for buccal carcinoma patients. J Can Res Ther 2016;12:1102-3
|How to cite this URL:|
Yangchen K, Singh SV, Aggarwal H, Singh RD, Siddharth R, Mishra N, Tripathi S. Cerrobend shielding stents for buccal carcinoma patients. J Can Res Ther [serial online] 2016 [cited 2019 Dec 12];12:1102-3. Available from: http://www.cancerjournal.net/text.asp?2016/12/2/1102/144688
| > Introduction|| |
The high-frequency of oral cancer in Asian countries has been known since the last century, buccal mucosa being the most common site. Radiation therapy is being used with increasing frequency in the management of such head and neck tumors. The adverse effects of radiotherapy manifest themselves in varying degree, depending upon factors such as volume of tissue irradiated, site and size of the tumor, type of radiotherapy technique used, etc., Stents may be constructed to protect healthy tissues from adverse effects of treatment and concentrate radiation in the region of the tumor mass. Lipowitz's alloy or Wood's metal (eutectic alloy of 50% bismuth, 26.7% lead, 13.3% tin, and 10% cadmium by weight), popularly known as cerrobend, is commonly used to shield uninvolved tissues from electron beams used in therapeutic radiation treatment of head and neck cancers. However, the technique for fabrication of such stents has not been documented properly. This article details such a technique.
| > Technique|| |
- Maxillary and mandibular impressions were made with irreversible hydrocolloid impression material and poured with type III gypsum
- After facebow transfer, interocclusal records were made with aluwax (Aluwax Dental Products Co., Michigan, United States) at maximum comfortable mouth opening of the patient
- After mounting on a semi-adjustable articulator, a 2 mm thickness of base plate wax (Maarc Goregoan, Mumbai, India) was adapted over the unaffected side of the maxillary cast extending to the mid-palatine raphe and facial sulcus, till the midline [Figure 1]
- A similar baseplate was adapted over the mandibular unaffected half up to the alveolo-lingual and facial sulcus till the midline [Figure 1]
- Occlusal rims of approximately similar height were then fabricated on these bases at the height decided by the interocclusal record [Figure 1]. It was ensured that the combined facio-lingual thickness of wax was at least 10 mm to provide adequate shielding of unaffected oral tissues from adverse effects of radiotherapy
- Nicks and notches were made on the occlusal surface of the maxillary and mandibular wax rims, so that the upper and lower separate parts interlock and maintain the desired position of the stent in the mouth
- The trial stents were then tried in the patient's mouth and adjusted
- The maxillary and mandibular trial stents were flasked and dewaxed identical to processing of heat cured acrylic dentures. Lipowitz's alloy (available commercially by the names of cerrobend, bendalloy, pewtalloy and MCP 158) is a low temperature casting eutectic alloy with a melting point of approximately 70°C (158°F)
- The cerrobend was liquefied in a casting crucible on a Bunsen burner and poured in the molds, followed by the flask closure. Care should be taken to use personnel protection devices such as gloves and mouth mask while melting and pouring the alloy
- Immediately after pouring the molten cerrobend alloy into the mold, the flask assembly was cooled evenly by immersing in water, to prevent flaws such as holes, dents, cracks and/or crystallization in the castings 
- The castings were recovered and finished and polished [Figure 2] in a similar fashion to other metal restorations. The stent was adjusted intraorally [Figure 3].
| > Discussion|| |
Radiotherapy has been used in the management of carcinomas of head and neck region for many years. External beam radiotherapy is generally used postoperatively or rarely as a primary treatment in advanced lesions. Radiation stents assist in the delivery of radiotherapy for carcinomas. These prostheses are used to protect or displace vital structures from the radiation field, locate diseased tissues in a repeatable position during radiation treatment, position the radiation beam, carry radioactive material or dosimetric devices to the tumor site, recontour tissues to simplify the therapy, or shield tissues from radiation. The use of shielding stent for buccal carcinoma besides protecting tissues of the contralateral side, simplifies dosimetry by flattening the affected cheek due to stretching action of the stent.
|Figure 2: Finished and polished shielding stent with indexed maxillary and mandibular components|
Click here to view
Using gloves and mouth mask are of utmost importance during processing as wood's metal contains lead and cadmium. Contact with bare skin may be harmful, especially in the molten state as vapors from this alloy carry the risk of cancer, anosmia and damage to the liver, kidneys, nerves, bones, and respiratory system.
| > Conclusion|| |
It is essential to be familiar with fabrication method of shielding stents for dental personnel, who should be an integral part of a multidisciplinary team treating an oral carcinoma patient by radiation therapy. This will aid predictable and fast service for such patients.
| > References|| |
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[Figure 1], [Figure 2], [Figure 3]