ESTRO 2025 - Abstract Book

S3946

Radiobiology - Normal tissue radiobiology

ESTRO 2025

3530

Digital Poster Dental Erosion as a Potential Amplifier of Radiation Therapy-Induced Effects on Dental Enamel Harley F Oliveira 1,2,3 , Tatiana A Pêcego 1 , Francisco J Q Thomé 4 , Fernando M Torres 5 , Kelly Molena 1 , Fernanda C Panzeri 1 , Eduardo Soares 1 , João Pedro Q Thomé 6 , Hanaya J M Oliviera 5 , Alexandra Mussolino de Queiroz 1 1 Department of Pediatric Clinics, School of Dentistry of Ribeirão Preto (FORP), Universidade de São Paulo – USP, Ribeirão Preto, SP, Brazil. 2 Department of Radiotherapy, Centro de Tratamento em Radio-Oncologia - CTR, Ribeirão Preto, SP, Brazil. 3 Department of Radiotherapy, Fundação São Francisco Xavier - FSFX, Ipatinga, MG, Brazil. 4 Department of Medical, Imaging, Hematology and Oncology, Ribeirão Preto Medical School - FMRP, University of São Paulo - USP, Ribeirão Preto, SP, Brazil. 5 Department of Oncology, Centro de Tratamento em Radio-Oncologia - CTR, Ribeirão Preto, SP, Brazil. 6 Orthopedics Department, Santa Casa de São Paulo, São Paulo, SP, Brazil Purpose/Objective: Throughout head and neck cancer (HNC) radiotherapy, several factors associated with dental erosion are present, posing a potential risk of exacerbating radiation-induced effects on teeth. Dental erosion is characterized by the progressive and irreversible loss of the mineralized structure of teeth through a chemical process that does not involve bacterial activity. It has a multifactorial etiology encompassing chemical, biological, and behavioral factors. Risk factors for dental erosion include low salivary flow rate, acidogenic diets, and recurrent episodes of regurgitation and vomiting, among others. This experimental study aimed to evaluate the effects of erosion associated with irradiation on the physical, mechanical, and morphological properties of dental enamel. Material/Methods: Healthy bovine teeth were used and divided into five groups based on the intervention received: Control (G1), Erosion (G2), Radiotherapy (G3), Radiotherapy + Erosion (G4), and Erosion + Radiotherapy (G5). Initial surface roughness and microhardness analyses were performed before the interventions. The irradiation protocol involved a total dose of 60 Gy (2 Gy/day, 5 days per week, over 6 weeks), while the erosion protocol used citric acid (pH 2.3) six times per day for 5 minutes with agitation, followed by 60 minutes of storage in a remineralizing solution after each erosive cycle, over 14 days. Post-intervention, final surface roughness and microhardness analyses were conducted, along with qualitative analysis via confocal laser scanning microscopy (CLSM). Data were analyzed using the Shapiro-Wilk normality test, one-way ANOVA, and Tukey's post-hoc test with a 95% significance level. Results: Physical, morphological, and mechanical alterations were observed in all groups subjected to interventions compared to the Control (G1), with the most significant changes observed in the Erosion (G2) and Erosion + Radiotherapy (G5) groups, which exhibited the lowest microhardness values. The Radiotherapy (G3) group showed the highest microhardness values, with statistically significant differences compared to all other groups. Surface roughness analysis revealed increased roughness in the Radiotherapy (G3) and Erosion + Radiotherapy (G5) groups relative to another group, with no significant difference between them. CLSM analysis revealed more demineralization points in the Erosion (G2) and Radiotherapy + Erosion (G4) groups. Grooves were observed in the Erosion + Radiotherapy (G3), while cracks were identified in the Radiotherapy (G2). Conclusion: In conclusion, dental erosion, both alone and in combination with different irradiation durations, leads to alterations in microhardness and demineralization of teeth, resulting in physical, morphological, and mechanical changes. These findings highlight dental erosion as a potential exacerbating factor for radiation-induced dental damage.

Keywords: head and neck cancer, dental erosion

References: Alfouzan AF. Radiation therapy in head and neck cancer. Saudi Med J. 2021 Mar;42(3):247-254