Salivary flow rate, subjective oral dryness and dental caries 5 years after haematopoietic cell transplantation.

Background: The aim of this study was to describe salivary flow rate, subjective oral dryness and dental caries 5 years post haematopoietic cell transplantation (HCT).

Methods: HCT survivors of a previous longitudinal observational cohort study in the Netherlands (the H-OME study) were invited to participate in this additional follow-up after 5 years (the HOME2 study). During the additional follow-up appointment, stimulated (SWS) and unstimulated whole saliva (UWS) was collected, participants rated subjective oral dryness on a 0 - 10 scale, and caries lesions were assessed. Furthermore, dental records, including treatments and radiographs, were requested for the 5 years preceding and the 5 years following transplantation. Paired t-tests were performed to determine changes in UWS and SWS flow rates and subjective oral dryness from pre-HCT, and to compare the number of caries-related dental treatments (restorations, endodontic treatments or extractions) before and after HCT. Hyposalivation of UWS (< 0.2 mL/min) and SWS (< 0.7 mL/min) at 3 and 12 months, was used to explore the predictive potential of hyposalivation on a high dental treatment need (> 3 treatments) over the 5 years post-HCT.

Results: Five years post-HCT, 39 HCT survivors were included. The mean UWS flow rate was 0.36 mL/min (SD 0.26) and the mean SWS flow rate 1.02 (SD 0.57); survivors were diagnosed with a median of 0 dentine lesions (range 0 - 12) and 73% reported a subjective oral dryness score ≥ 1. Survivors underwent a median of 3 (range 0 - 20) dental treatments during the 5 years following transplantation. The mean difference in UWS 5 years post-HCT compared to pre-HCT was 0.03 (95% CI: -0.07 - 10.12), the mean difference for SWS was -0.18 (95% CI: -0.45 - 0.08) and for subjective oral dryness 1.2 (95% CI: 0.2 - 2.1). In the 5 years post-HCT, non-significantly more treatments were performed compared to the 5 years pre-HCT (mean difference: 0.5, 95%CI: -1.2 - 2.2). Seventy eight percent of patients with hyposalivation of SWS at 12 months had a high dental treatment need, compared with 38% with no hyposalivation.

Conclusions: Five years post-HCT, mean UWS and SWS flow rates were not significantly different from pre-HCT levels but subjective oral dryness scores were elevated.