Free Amino-acid Composition of Peri-implant and Periodontal Conditions

Unstimulated, whole saliva was collected from all participants across the six study groups following a detailed explanation of the procedure. Initially, individuals were asked to rinse their mouths with filtered water and remain seated in a relaxed position for five minutes. Then, they were instructed to passively drool into a sterile collection tube over a 10-minute period.31 The collected saliva samples were then centrifuged at 3000 ×g for 10 minutes to remove debris and prepare them for storage at -80°C .

Saliva samples were deproteinized by mixing with 6% sulfosalicylic acid in a 1:1 ratio, followed by incubation at room temperature for 5 minutes. The mixtures were then centrifuged at 15,000 rpm for 5 minutes. A 10 µL aliquot of the resulting supernatant was diluted with 800 µL of 2 mM tridecafluoroheptanoic acid containing 0.375 M glucosaminic acid and internal standards. The prepared solutions were transferred into autosampler vials for analysis. Calibration standards were generated by combining known concentrations of amino acid standards.