Impact of Hyperglycemia on Xerostomia and Salivary Composition and Flow Rate of Adolescents with Type 1 Diabetes Mellitus

Xerostomia is defined as a subjective sensation of having a dry mouth (Fox et al., 1987) and is reported by the patient (Guggenheimer & Moore, 2003; Moore et al., 2001). The subjective feeling of dry mouth (xerostomia) is one of the oral manifestations of diabetes (Sreebny et al., 2006; von Bültzingslöwen et al., 2007). Xerostomia results from a reduction in saliva secretion, although it may occur in spite of the presence of a normal salivary flow rate (Guggenheimer & Moore, 2003; Scully, 2003). Altered saliva composition rather than the quantity of saliva may play a role in the induction of xerostomia (Anttila et al., 1998; Fox, 1996). Type 1 diabetes mellitus (DM1) is a metabolic dysfunction characterized by hyperglycemia resulting from definitive deficiency in insulin secretion caused by autoimmune illness and genetic factors (ADA, 2004). The American Diabetes Association (ADA) reports that 75% of DM1 cases are diagnosed in persons under the age of 18 years (ADA, 2006). Glycemic control is fundamental to the management of diabetes and is associated with sustained decreased rates of microvascular (retinopathy and nephropathy) as well as neuropathic complications (ADA, 2008). Glycemic control has a modifying effect on the relation between dental caries and salivary factors in young patients (Syjälä et al., 2003). Patients with DM1, particularly those who have poor glycemic control, may have decreased salivary flow rate (Guggenheimer & Moore, 2003). Many clinical problems develop in the presence of xerostomia, such as: difficulty in swallowing and speech, high susceptibility to oral infections (mainly candidiasis and dental caries), gingivitis and mucositis (Anttila et al., 1998). Furthermore, xerostomia was shown to have a negative impact on the quality of life of adolescents with DM1 (Busato et al., 2009). The relationship among DM1, salivary composition and xerostomia has been widely investigated (Swanljung et al., 1992; Moore et al., 2001; López et al., 2003; Siudikiene et al., 2006; Siudikiene et al., 2008; Orbak et al., 2008). It has been found that most DM1 patients have salivary dysfunction as well as differences in biochemical salivary composition compared with healthy subjects (Swanljung et al., 1992; Moore et al., 2001; López et al., 2003; Siudikiene et al., 2006; Siudikiene et al., 2008; Orbak et al., 2008). Moreover, there is a lack of studies showing the relationship among hyperglycemia, xerostomia and salivary factors, especially in