Symptomatic hyposalivation is associated not only with Sjögren's syndrome or salivary gland hypofunction in elderly patients, but also with medications containing antimuscarinic drugs, chemo radiotherapy for head and neck carcinomas, and psychiatric disorders (Atkinson & Ava, 1994, Kielbassa et al., 2006).

Human saliva possesses important physiological functions in protecting and moistening the oral hard and soft tissues (Piotrowski et al., 1992, ). Consequently, decreasing salivation causes oral dysfunction and promotes severe oral side effects (reduced antibacterial function, lack of remineralisation, reduced buffer capacity) (Tschoppe et al., 2010a). These have been identified as being responsible for the rapid destruction of the dentition (Willich et al., 1988). Saliva substitutes are frequently applied for relieving the symptoms in patients suffering from hyposalivation (Hahnel et al., 2009, Nieuw Amerongen & Veerman, 2003, Vissink et al., 2004). Besides the moistening and lubrication of the oral mucosa, these products should also protect dental hard tissues. However, in vitro studies revealed that some marketed products have only a neutral or even a demineralising potential on enamel as well as on dentin (Kielbassa et al., 2001, Meyer-Lueckel et al., 2002, Smith et al., 2001, Tschoppe et al., 2009). Inorganic ions such as calcium, phosphates, and fluorides have been added to saliva substitutes in order to enhance their remineralising property or minimize their demineralising potential (Tschoppe et al., 2009). Furthermore, as most patients suffering from hyposalivation are elderly people, recessions and subsequently exposed dentin surfaces are very common. Since dentin is not as acid resistant as enamel, an earlier and more severe demineralisation can be expected (Saunders & Meyerowitz, 2005).

Therefore, the current in situ study was performed to assess the effects of a demineralising and a remineralising saliva substitutes on the mineralisation of dental hard tissues. It was hypothesized that storage in Glandosane(cell pharm, Hannover, Germany) would not result in pronounced mineral loss of dentin specimens, and that storage in Saliva natura would not result in enhanced remineralisation when combined with a remineralising artificial saliva (Saliva natura supersaturated with respect to relevant calcium phosphates; medac, Hamburg, Germany) (H0). These null hypotheses were tested against the alternative hypothesis of a difference.

see application for the German Federal Institute for Drugs and Medical Devices at Eudra-CT

Inclusion Criteria:

• stimulated salivary flow rate < 0.5 ml/min
• partial denture upper or lower jaw
• radiationtherapy in the head and neck area
• patient age above 18 years
• Signed informed consent (AMG §40 (1) 3b)

Exclusion Criteria:

• stimulated salivary flow rate > 0.5 ml/min
• missing partial denture upper or lower jaw
• missing Radiationtherapy in the head and neck area
• paraben allergy
• not signed informed consent (AMG §40 (1) 3b)