Caries Progression after Haematopoietic Stem Cell Transplantation and the Role of Hyposalivation

Abstract

Haematopoietic stem cell transplantation (HSCT) preceded by a conditioning regimen is an established treatment option for many haematological diseases. Decreased salivary flow rates after HSCT may increase caries risk. We aim to estimate the extent to which caries lesions develop or progress in adult HSCT recipients and assess its association with salivary flow rates. A multi-centre prospective observational study was conducted in which patients receiving HSCT were followed up for 18 months. We included 116 patients (median age 56 years, 43% female) from two medical centres in the Netherlands. Unstimulated whole saliva (UWS) and stimulated whole saliva (SWS) were collected, and full caries charts were made before HSCT and 3, 6, 12, and 18 months post-HSCT. Caries was scored according to the ICDAS criteria by trained dentist-examiners. New dentine lesions or lesion progression into dentine (ICDAS ≥4 or cavitated root lesions) occurred in 32% of patients over 18 months. The median number of affected surfaces was 2 (range: 1-12) per patient with caries progression. The influence of hyposalivation of unstimulated saliva (<0.2 mL/min) and stimulated saliva (<0.7 mL/min) at baseline and after 3 months on caries progression was determined with a negative binomial regression model. Hyposalivation of SWS 3 months after HSCT was a significant risk indicator for caries progression (incidence rate ratio: 5.30, 95% CI: 2.09-13.4, p < 0.001), while hyposalivation of SWS at baseline and hyposalivation of UWS were not. We conclude that caries progression is a common oral complication in patients after HSCT, and stimulated hyposalivation shortly after treatment is a significant risk indicator for caries progression.

Keywords: Dental caries; Haematopoietic stem cell transplantation; Hyposalivation.

Fig. 1

Flow chart of the study. A distinction is made between patients treated at AMC (A) and Radboudumc (R). Reasons for exclusion and irreversible loss to follow-up are shown in the squares on the left and right sides of this diagram. Reasons for 21 incidental missed appointments of 18 patients, marked with * in this diagram, were: unable to come due to hospitalization, rehabilitation or illness (n = 5), refused to come or did not come (n = 7), unreachable (n = 3), or other/unknown reasons (n = 6).

Fig. 2

Number of surfaces with dentine lesions at baseline (blue bar) and cumulative number of surfaces with new or deeper dentine lesions that developed in different time periods (orange/red bars). Numbers (top row, total) shown in the graph represent the numbers of patients that were seen for follow-up in the mentioned time period. Numbers in the second row (≥1 lesion) represent patients with at least 1 dentine lesion at baseline or lesion progression during the follow-up. A distinction is made between cavitated root lesions, cavitated coronal lesions (ICDAS 5 and 6), and non-cavitated coronal lesions (ICDAS 4).

Fig. 3

Mean ± 1 SD UWS (a) and SWS (b) flow rates in patients with (solid line) and without (dashed line) caries progression. Two UWS samples of 1 patient were missing due to chewing gum use before the collection and saliva sampling in one autologous patients took place after 6 instead of 3 months.