OBJECTIVETo investigate the change of secretory leukocyte protease inhibitor (SLPI) and elastase (EA) in the different stages of periodontal inflammation and to evaluate the possibility of the two proteins as saliva markers reflecting overall periodontal health status.

METHODSUnstimulated whole saliva were collected from 86 subjects (divided into 4 groups as healthy, gingivitis, moderate periodontitis and severe periodontitis). Fifteen patients with moderate or severe periodontitis were only given scaling and root planning (SRP). Whole saliva was collected and clinical patameters were recorded at baseline and four weeks after the treatment. SLPI concentrations were determined with enzyme linked immunosorbent assay (ELISA) systems, while EA with low-molecular-weight substrate reaction.

RESULTSThere were no statistical differences of SLPI concentrations among four groups (P > 0.05). However, EA activities in moderate periodontitis and severe periodontitis groups [0.077 (0.060) and 0.077 (0.489)] were higher than in healthy and gingivitis group [0.058 (0.028) and 0.058 (0.024)] (P < 0.05). SLPI only showed a weak negative correlation with age (r = -0.301, P < 0.05), rather than with EA or clinical parameters. In 15 patients with chronic periodontitis the mean concentration of SLPI and EA activity was 2.031 (2.449) µg/L and 0.075 (0.118), and both decreased significantly to 1.405 (0.659) µg/L and 0.055 (0.028) respectively 4 weeks after SRP.

CONCLUSIONSAfter SRP, the decrease of SLPI concentration and EA activity in saliva may reflect the periodontal inflammation subsiding. SLPI in saliva was not correlated with the development of periodontal inflammation.