The role of mouthguard customization to minimize risk of radiation backscatter in head and neck cancer patients

Abstract

Purpose/Objective(s) Head and neck cancer (HNC) patients undergoing radiation therapy can experience radiation induced oral mucositis (RIOM) due to backscatter from metallic dental restorations. The efficacy of customized mouthguards in absorbing backscattered radiation was measured. Materials/Methods Mouthguards were used on a dental teaching model known as a typodont containing teeth with and without metal restorations: commercial guard 1, commercial guard 2, a custom acrylic guard, and three guards constructed of NextDent Gingiva (NG) with thicknesses of 3, 5, and 7mm. The typodont was irradiated in a 6 MV open field with each mouthguard in place. Radiographic film was used to measure the dose on the surface of the mouthguard and on the teeth without the mouthguard present. Films were digitized using a flatbed scanner. The red channel was extracted and the film was converted from optical density to dose. Dose profiles across the mouthguards were extracted. The ratio of the dose to the film positioned over the largest restoration to the dose positioned over a tooth without a restoration (termed dose enhancement) was calculated for each set up. Results The dose enhancement for each mouthguard measured for the largest restoration is shown in Table 1. Profiles showed consistent dose enhancement across all restorations for each mouthguard, except for the commercial guard 2 which was not long enough to cover all of the restorations in the denture model. Dose enhancements greater than 1.10 were seen on the film near the location of the restoration not covered by commercial guard 2. The backscatter radiation was reduced with the use of Acrylic and 3mm NG guards while fully absorbed by both of the commercial, 5mm NG and 7mm NG guards. Conclusion The proposed 5-7mm NG guards effectively absorb backscatter and fully cover teeth with metal restorations. Customization allows for thicker protection around restored teeth whilst residual thinner protection elsewhere, enhancing comfort, treatment adherence, and quality of life for patients. Implementing these mouthguards into clinical practice holds value as these patients traditionally have difficulty tolerating mouthguards in a confined, radiation-vulnerable oral environment exacerbated by mucositis.