Worsening of Oral Health Parameters After Head and Neck Radiotherapy—Findings from a Multidisciplinary Head and Neck Tumor Board: A Prospective Observational Study

Objectives: To evaluate (a) changes in caries experience, (b) changes in periodontal status, and (c) the need for dental extractions in a cohort of patients treated with radiotherapy (RT) and chemoradiotherapy (RTCT) for head and neck cancer (HNC). Methods: This prospective cohort study was approved by the local Ethics Committee (Ref. 22858/18) and registered at ClinicalTrials.gov (ID: NCT04009161). The study population consisted of patients with HNC who, prior to RT, underwent a dental examination followed by the elimination of oral foci of infection and were then enrolled in a follow-up program. The primary outcome was oral health worsening, defined as the onset of severe periodontitis and/or a DMFt score ≥ 13. Oral cavity RT dose was obtained contouring the ‘buccal mucosa’ organ at risk (OAR). Results: In total, 113 patients were included (median follow-up: 44.77 months). The sample mainly included oral, oropharyngeal, nasopharyngeal and laryngeal cancers (89/113, 78.8%). Salivary glands, hypopharynx and other sites accounted for a minority of the cases (24/113, 21.2%). Seventeen patients (34.7%) experienced worsening of oral health status over time, which was associated with smoking (OR = 4.7, 95% CI: 1.27–17.37; p = 0.02). The DMFt index increased (difference: 4.08; 95% CI: 1.60–6.56; p = 0.001), and this increase was associated with smoking (β = 2.05, 95% CI: 0.27–3.83; p = 0.02). Although worsening of periodontitis stage was not statistically significant (p = 0.35), localized deterioration was observed, with an increase in sites with PPD ≥ 5 mm (p = 0.02). Forty-nine patients (43.4%) experienced tooth loss. Mean tooth loss was 2.12 teeth per patient (p = 0.05), primarily due to caries (48.5%) and periodontitis (48.1%). Independent risk factors for tooth loss were age (p = 0.025) and an RT dose > 60 Gy to the ‘buccal mucosa’ OAR (p = 0.023). Conclusions: Patients treated with RT experienced significant deterioration in dental and periodontal health, and oral cavity dosimetric parameters might be associated with tooth loss, although this association requires confirmation in further studies.