The palate and upper lip are the regions of oral mucosa covered with the least amount of saliva. These areas are important for maxillary denture retention and stability. Thus, patients with xerostomia or hyposalivation may have problems with the stability of maxillary complete dentures.
The purpose of this study was to compare the unstimulated whole saliva (UWS) and palatal saliva (PS) flow rates of healthy patients wearing complete dentures and patients with Sjogren's syndrome (SS) and to determine whether xerostomia or hyposalivation has a negative influence on maxillary complete denture stability. A further aim was to determine the influence of new complete dentures on UWS and PS flow rates in healthy individuals.
Thirty-five complete denture wearers, 24 healthy individuals (controls) and 11 patients who fulfilled the diagnostic criteria for primary Sjogren's syndrome (as proposed by the European Community Study Group) were investigated. All participants were questioned about possible subjective oral complaints (xerostomia or instability of the dentures) through use of a standardized questionnaire. In the first part of the study, UWS and PS flow rates of the healthy subjects (controls) and of the SS patients were measured at the initial visit. The flow rate of UWS (mL/min) was collected by the "spitting" method; saliva was collected into preweighed vessels for 5 minutes while subjects were seated in an upright position. Patients were asked to refrain from smoking, eating, and drinking for 2 hours prior to the test session, to avoid swallowing, and to make as few movements as possible during the procedure. The PS flow rate (microL/min/cm2) was measured using previously weighed filter paper discs placed bilaterally in the region of the maxillary second molars, 15 mm palatally from the edentulous ridge, for 30 seconds. The measuring vessels and paper discs were weighed before and after each collection. In the second part of the study, new complete dentures were fabricated for healthy patients. Flow rates of UWS and PS were measured 7 days after the insertion to compare data with prefabrication values. Mann-Whitney and Wilcoxon rank sum tests and chi-square test were used to analyze the data (alpha=.05).
The UWS flow rates were significantly lower in SS patients compared to healthy controls (0.36 +/- 0.33 vs 0.09 +/- 0.11 mL/min, P<.05), yet the PS flow rate for both groups was not significantly different. Although every SS patient had xerostomia, and 8 out of 11 had hyposalivation, no patient complained about denture instability. Neither UWS flow rate (0.36 +/- 0.33 mL/min and 0.39 +/- 0.35 mL/min) nor PS flow rate (1.66 +/- 0.99 microL/cm2/min and 1.86 +/- 0.45 microL/cm2/min) was different from the preinsertion values after 1 week of new denture insertion in healthy patients.
Palatal mucous saliva may help stabilize the maxillary complete denture in patients with hyposalivation. The results suggest that neither UWS or PS flow rate are influenced by the placement of new dentures in complete denture wearers.