A commonly held view by clinicians is that the salivary gland hypofunction associated with primary Sjögren's syndrome (SS-1) is more severe than that associated with secondary Sjögren's syndrome (SS-2). This study aimed to determine if this view could be substantiated, when applied to a large sample group.
Unstimulated and paraffin wax-stimulated whole salivary flow rates were retrospectively compared for age and gender matched, patients diagnosed with SS-1 or SS-2 according to the preliminary European criteria. The patients had attended the Xerostomia Clinic, in the Oral Medicine Department, at the Liverpool University Dental Hospital.
Sixty-seven patients with SS-1 (average age 57.1 years) were matched with 67 patients with SS-2 (average age 57.6 years), according to gender and age, within 5 years. The mean unstimulated whole salivary flow rates (+/- s.d.) for patients with SS-1 and SS-2 were 0.11 (+/- 0.15) and 0.12 (+/- 0.18) mL min-1 respectively. The mean paraffin wax stimulated, whole salivary flow rates (+/- s.d.) for patients with SS-1 and SS-22 were 0.45 (+/- 0.02) and 0.47 (+/- 0.49) mL/min-1 respectively. No significant differences, in either stimulated (P = 0.54) or unstimulated (P = 0.60) whole salivary flow rates were found between individuals with SS-1 or SS-2.
The severity of salivary gland hypofunction does not appear to be related to the clinical variant of Sjögren's syndrome.