The Effect of Chronic Graft-Versus-Host Disease and Its Therapy on Salivary Caries Risk Factors—An Exploratory Cross-Sectional Pilot Study

<b>Background</b>: The aim of this study was to investigate the effects of chronic graft-versus-host disease (cGVHD) and its treatment with cyclosporine and extracorporeal photopheresis (ECP) on salivary caries risk factors. <b>Methods</b>: In this exploratory single-centre cross-sectional pilot study, saliva samples from 22 cGVHD patients were analysed for flow rate, pH, buffering capacity, and counts of <i>Streptococcus mutans</i> and <i>Lactobacillus</i>. A detailed dental examination assessed plaque, carious lesions, and their progression. Caries risk was determined based on general health and diet questionnaires and clinical findings. <b>Results</b>: Patients receiving a combination of cyclosporine and ECP had significantly fewer carious teeth, affected tooth surfaces, and non-cavitated carious lesions compared with those treated with ECP alone (Bonferroni test, <i>p</i> = 0.004, <i>p</i> = 0.002, and <i>p</i> < 0.001, respectively). Patients treated with ECP had more carious teeth and affected surfaces than those who did not receive either ECP or cyclosporine (<i>p</i> = 0.008 and <i>p</i> = 0.002), whereas patients treated with cyclosporine only had more non-cavitated lesions than those receiving both cyclosporine and ECP (<i>p</i> < 0.001). A negative correlation was observed between cyclosporine dose and stimulated salivary flow (R = -0.672, <i>p</i> = 0.0486), and a positive correlation between cyclosporine dose and caries risk (R = 0.640, <i>p</i> = 0.0461). <b>Conclusions</b>: The disease and its treatment were associated with reduced salivary flow and increased caries risk. Patients' oral health should be monitored regularly and managed with care to prevent further deterioration.