Saliva Levels of IL-18 in Healthy and Peri-implantitis Patients

Abstract

Title of Thesis: Saliva Levels of IL-18 in healthy and peri-implantitis patients Purpose: Peri-implantitis is a common problem that occurs in 9.25% in functioning implants and approximately 20% of patients. Our understanding of the etiology of Peri-implantitis is limited. Understanding molecular mechanisms associated with peri-implantitis may help in developing and improving treatments for peri-implantitis. The purpose of this study was to assess the levels of IL-18 in saliva of healthy patients and patients diagnosed with peri-implantitis. Materials and Methods: Institutional Review Board approval was obtained. Unstimulated saliva was collected from a total of 24 subjects (peri-implantitis n=14, healthy n=10). Saliva was collected from subjects using 15 ml tubes every minute for 5 minutes. Collected saliva were then centrifuged for 5 minutes at 10,000 x g. The aliquot layer was collected and immediately stored at -80°C until analysis. The concentration level of IL-18 was measured using high-sensitivity enzyme-linked immunoabsorbent assays (ELISA). All statistical analyses were performed using Microsoft® Excel®. Statistical comparisons were tested for normality followed by the Mann Whitney U test. Results: Twenty-four subjects with 33 implants were analyzed. Twenty-two implants were diagnosed with peri-implantitis, while the remaining 11 were healthy controls. The Median values of IL-18 analytes were 1.92 pg/ml for peri-implantitis and 2.23 pg/ml for healthy control. The range was 8.58 pg/ml for peri-implantitis (min 0.079 pg/ml – max 8.66 pg/ml). The range was 21.26 pg/ml for healthy control (min 1.13 pg/ml – max 22.39 pg/ml). The mean was 5.47 pg/ml for healthy control and 2.61 pg/ml for peri-implantitis. The standard deviation was 6.80 pg/ml for healthy control and 2.04 pg/ml for peri-implantitis. Conclusions: In non-smoking patients not suffering from diabetes or other inflammatory disease, it appears that the levels of IL-18 are comparable to those of healthy patients.