Investigation of Dosage Distributions of Polyvinyl Siloxane Dental Impression Shields for Head and Neck Radiotherapy with Thermoluminances Dosimeters

Abstract

Objective: This study aimed to assess the effects of denture materials on dose distribution on a head and neck radiotherapy-appropriate model and calculate the thickness of a stent by polyvinyl siloxane dental impression material for shielding scattered radiation from dental restorations.
 Methods: In the first step of the study, 5mm diameter and 5mm height of cylindrical dental material of titanium, zirconia lithium disilicate were irradiated with 6-Megavoltage photons from a clinical linear accelerator. In the second step, dental materials at the center of polyvinyl siloxane thicknesses of 5, 10, and 20mm were irradiated with 2 Gray and 10 Gray fractional doses. Measurements were made using three thermoluminescent dosimeters positioned laterally. The percentage backscattered dose and percentage dose decrease values were calculated to interpret the results. 
 Results: According to the result, dosages scattered from dental materials increased for samples irradiated with 2Gy; a decreased dose was reported for samples irradiated with a 10Gy. 5mm PVS samples provided higher dose attenuation than others. Regardless of dental material, it is seen that the attenuation intensities calculated from TLD-100 dosimeters ranged from 22.7 to 38,62 for 2Gy, and 10.01 to 38,87 for 10Gy.
 Conclusion: Dental material alters the scattered radiation. In irradiated head and neck cancer patients, a 5mm thick guard is sufficient to prevent radiation diffused from dental materials in clinical usage.