title: A comparison of salivary gland hypofunction in primary and secondary Sjögren's syndrome.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  The severity of salivary gland hypofunction does not appear to be related to the clinical variant of Sjögren's syndrome.
authors.affiliation: Liverpool Sjögren's Syndrome Research Group, Department of Clinical Dental Sciences, University of Liverpool, UK.
authors.forename: L J
authors.initials: LJ
authors.lastname: Dawson
authors.forename: D J
authors.initials: DJ
authors.lastname: Holt
authors.forename: S M
authors.initials: SM
authors.lastname: Higham
authors.forename: L P
authors.initials: LP
authors.lastname: Longman
authors.forename: E A
authors.initials: EA
authors.lastname: Field
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012469:Salivary Glands / Q000503:physiopathology*; D012859:Sjogren's Syndrome / Q000145:classification* / Q000503:physiopathology*; D014987:Xerostomia / Q000503:physiopathology