The Association of Salivary Flow Rate and Sleep Quality among Head and Neck Cancer Survivors after Radiotherapy

Background Head and neck cancer survivors sufer from xerostomia and sleep disturbances after radiotherapy,
both of which afect their quality of life. This study aimed to explore the role of salivary fow in the oral health
and sleep quality of head and neck cancer survivors.
Methods We recruited 120 head and neck cancer survivors who were experiencing symptoms of dry mouth or sleep
disturbances post-radiotherapy from a dental clinic. We gathered their socio-demographic and clinical data, meas‑
ured their salivary fow rate, and recorded their dry mouth score using the summated xerostomia inventory. Addi‑
tionally, a dentist collected the DMFT (Decayed, Missing, and Filled Teeth) index. The Pittsburgh Sleep Quality Index
was employed to assess their sleep quality.
Results In this study, xerostomia was observed in nearly 80% of the cancer survivors. The concurrent prevalence
of sleep disturbance and xerostomia was at 55%. After fve years post-radiotherapy, there was a signifcant improve‑
ment observed in both the quality of sleep (p = 0.03) and the stimulated salivary fow rate (p = 0.04). Additionally,
these improvements were noted to have commenced from the third year onwards. A signifcant association
was found between stimulated salivary fow and dry mouth scores with poor sleep quality (p< 0.05).
Conclusions We recommend that dental professionals prioritize managing both dental and mental health issues
equally for head and neck cancer survivors who have undergone radiotherapy within the past 3 years.
Keywords Pittsburgh sleep quality index, Salivary fow, DMFT, Radiotherapy, Head and neck cancer