Aim:
To investigate the mineral homeostasis of oral liquid in patients affected by periodontitis and to analyze the impact of the implemented non-surgical therapy on the content of trace elements in the oral liquid at different observation periods, which depended on the severity of the disease.

Material and methods:
There were somatically healthy individuals enrolled in this study, among them were 70 patients with periodontitis stage I and II, grade A and B and 17 individuals with intact periodontium. The content of Iron, Zinc, Copper and Manganese in oral liquid was determined by adsorption spectrophotometer before, after and 6 and 12 months following the treatment. Comprehensive non-surgical treatment included exo- and endogenous therapy with the microalgae Spirulina platensis.

Results:
Examination of all patients with periodontitis demonstrates the content of biometals in the oral liquid with a probably decrease of Iron, Zinc, Manganese and an increase of Copper (p<0.001). Changes in the mineral composition depended on the stage and degree of severity and were intensified in the subgroup I B, and even more so in the subgroup II B. After complex treatment administered the amount of Copper and Manganese was normalized (at all terms, for both stages of the disease) and the content of Iron and Zinc was also regulated (especially 6 months after in the subgroups IA and IIA).

Conclusions:
It was established that the method of complex treatment based on administration of the blue-green microalgae Spirulina platensis contributes to the normalization of trace element composition in the oral liquid of patients with periodontitis.