OBJECTIVEWe detected and analyzed the clinical values of total protein (TP), albumin (ALB), globulin (GLB), and ALB/GLB ratio (A/G) of whole unstimulated saliva of healthy people to determine the time of day when saliva composition is relatively stable. We compared the protein concentration and A/G of whole unstimulated saliva of patients with chronic periodontitis with those of healthy volunteers to provide references for diagnostic methods and clinical applications of saliva.

METHODSThe whole saliva of 37 healthy subjects were collected at 8:00, 9:30, 11:30, 13:00, 16:30, and 21:00. Meanwhile, the whole saliva of 24 patients with periodontitis was collected in the morning. Bicinchoninic acid method was used to detect the TP content. Saliva ALB was detected by GF-D800 semi-automatic biochemical analyzer, and the GLB and A/G were calculated. Finally, the results were statistically analyzed using SPSS 19.0.

RESULTSSalivary protein compositions were stable in the morning on an empty stomach. Healthy people: TP, (1 354.35±389.52) µg.mL-1; ALB, (139.55±27.19) µg.mL-1; GLB, (1 211.80±360.73) µg.mL-1; A/G, 0.126 3±0.041 7. Subjects with chronic periodontitis: TP, (2 611.56±231.62) µg.mL-1; ALB, (296.27±17.34) µg.mL-1; GLB, (2 315.69±221.67) µg.mL-1; A/G, 0.156 2±0.017 3. The contents of TP, ALB, and GLB in healthy individuals at different periods within a day showed significant differences (P<0.05), which were mainly reflected in the levels before and after meals. No significant difference was detected in A/G. The concentrations of TP, ALB, and GLB were significantly increased in patients with chronic periodontitis compared with those in healthy volunteers. However, no significant difference existed in A/G.

CONCLUSIONSalivary protein compositions are more stable in the morning than in other periods. Thus, mornings can be set as the time of specimen collection in future research. The concentrations of TP, ALB, and GLB in patients with chronic periodontitis are higher than those in healthy people.