Saliva plays a significant role in the maintenance of oral hard and soft tissue integrity as well as for the oral microflora by providing mechanical cleansing, buffering effect and antimicrobial actions. Saliva not only enhances the clearance of micro-organisms and dietary carbohydrates from the oral cavity, but also regulates the composition and growth conditions of the oral microflora. It is well documented that the susceptibility to dental caries and oral mucosal infections is increased in patients suffering from low saliva flow rates. Nonetheless, only a limited number of studies have dealt with the impact of salivary gland hypofunction on the composition of oral microflora. Most of these studies have not included additional variables regarding environmental and behavioural factors that may contribute to changes in the oral microflora such as dental and general health status and sugar intake. This review has its main focus on the oral microflora in patients suffering from salivary gland hypofunction, be it temporary or permanent, due to different aetiologies like Sjgrens syndrome, radiation therapy of tumours in the head and neck region, cancer chemotherapy and intake of other medications. It also outlines the methods used for assessment of oral micro-organisms, and the numerous underlying factors affecting the interpretation of salivary and oral microbial findings.
Despite the different causes of salivary gland hypofunction, these patient groups show some similarities with regard to their oral microbial composition and increased counts of oral pathogens associated with caries activity (mutans streptococci and lactobacilli) and mucosal infections (in particular, Candida albicans).
Sjgrens syndrome, cancer therapy, medication, Candida, lactobacilli, mutans streptococci