Characteristics of the saliva flow rates of minor salivary glands in healthy people

• Minor salivary glands flow rate in a large number of healthy subjects was measured.
• Normal ranges of mean flow rate of different minor salivary gland were provided.
• Buccal glands and 10–14-year-old group had a highest saliva flow rate.
• No obvious effect of acid stimulation on secretion of minor salivary gland was found.
• A significant circadian effect was found only in the labial glands.

ObjectivesTo investigate the normal range and characteristics of saliva secretion in the minor salivary glands (MSGs).DesignThe flow rates of MSGs were measured in 4 anatomical locations of oral mucosa, and the relationship between MSG flow rates and whole saliva flow rates were assessed in 300 healthy subjects stratified by age and sex. An additional 30 young females were further evaluated for flow symmetry, effects of stimulation, circadian effects in MSGs, and the relationship with the flow rates of major salivary glands.Results(1) The mean saliva flow rates were 2.10 ± 0.66 (lower labial glands), 2.14 ± 0.62 (upper labial glands), 2.88 ± 0.72 (buccal glands) and 2.15 ± 0.51 (palatal glands) μl/min/cm2, respectively. The flow rate of buccal glands was significantly higher than the rates of SMGs in other locations (P < 0.01). (2) 5-year-old children had the lowest MSG flow rates (P < 0.0001) while the 10–14-year-old group had the highest (P < 0.001). (3) MSG flow rates were independent of sex (P > 0.05), right vs. left (P > 0.05), and citric acid (2.5%) stimulation (P > 0.05). (4) Only labial MSG displayed a significant secretory circadian rhythm with the highest rate in the evening (P < 0.05). (5) A weak correlation was found between the flow rate of palatal glands and that of unstimulated whole saliva (r = 0.195, P = 0.007).ConclusionsOur findings provide a reference for functional evaluation of MSGs and for donor site selection of MSG transplantation for treatment of severe dry eye syndrome.