Tongue pressure during swallowing in adults with down syndrome and its relationship with palatal morphology.

In individuals with Down syndrome, hypotonicity of the tongue and an underdeveloped maxilla may lead to poor oral motor coordination, which adversely affects the oral phase of swallowing. This study aimed to evaluate the characteristics of pressure produced by the tongue against the hard palate during swallowing in individuals with Down syndrome. In addition, the relationship between tongue pressure and palatal morphology was examined. We studied nine adults with Down syndrome and ten healthy adults as controls. Tongue pressure while swallowing 5 mL water was recorded by a sensor sheet system with five measuring points attached to the hard palate. Palatal length, depth, width, curvature, and slope were measured by three-dimensional digital maxillary imaging. The order of onset of tongue pressure on the median line of the hard palate was the same in all participants, except for three with Down syndrome. The duration and maximal magnitude of tongue pressure on the median line in nine participants with Down syndrome were significantly shorter and lower than those of controls. In participants with Down syndrome, significant positive correlations were observed between the duration of tongue pressure at the mid-median part of the hard palate and palatal depth and width, and between the duration and maximal magnitude of tongue pressure at the posterior-median part and palatal length. These findings suggest that impaired tongue activity, poor tongue control, and constrained tongue motion due to a short and narrow palate contribute to swallowing difficulty in individuals with Down syndrome.

Increased oxidative stress biomarkers in the saliva of Down syndrome patients.

OBJECTIVE: The DNA oxidation byproduct 8-hydroxy-2'-deoxyguanosine (8-OHdG) is a well-known biomarker used to evaluate oxidative stress. We previously reported that the generation of reactive oxygen species (ROS) is increased in cultured gingival fibroblasts (GF) from patients with Down syndrome (DS). Thus, the aim of this study was to evaluate 8-OHdG as a marker of oxidative stress in saliva of DS patients. MATERIALS AND METHODS: The study group consisted of DS patients (66 patients; age range 1-62 years) and systemically healthy control subjects (71 subjects; age range 4-58 years). Periodontal status was judged based on standard measurements of probing depth (PD) and gingival index (GI). The salivary levels of 8-OHdG were determined using an enzyme-linked immunosorbent assay. RESULTS: The mean of PD and GI values were not significantly different between young (1-12 years) patients with DS (DS-1) and controls (C-1) or between adult (30-62 years) patients with DS (DS-2) and controls (C-2). There were statistically significant positive correlations between the salivary 8-OHdG levels and GI in the DS-1, DS-2 and C-2 groups, but not in the C-1. There were also statistically significant positive correlations between salivary 8-OHdG levels and PD in the DS-2 and C-2 groups, but not in the DS-1 or C-1 groups. The salivary levels of 8-OHdG of DS-1 and DS-2 groups were significantly higher than in the C-l and C-2 groups, respectively. CONCLUSIONS: These results suggest that progressive oxidative stress occurred in DS patients. Oxidative stress may contribute to the clinical features of DS, particularly to the progressive periodontitis characteristic of early ageing.