TREM‐1 Pathway Biomarkers for Classification of Periodontal Diseases and Monitoring of Treatment Response in Grade B and C Periodontitis

ABSTRACT Background This study investigated the diagnostic potential of salivary triggering receptor expressed on myeloid cells (TREM)‐1, peptidoglycan recognition protein 1 (PGLYRP1) and interleukin (IL)‐1β for periodontitis patients and their ability to predict treatment outcome. Methods Systemically healthy, non‐smokers with gingivitis ( n = 31), stage III periodontitis (34 grade B: n = 34, grade C: n = 24) and healthy controls ( n = 34) were recruited. Periodontitis patients ( n = 42) underwent non‐surgical periodontal treatment. Saliva was collected at baseline (T0) and post‐treatment (T1, T3, T6). Biomarkers were measured using immunoassays. Periodontitis patients were categorised into responders ( n = 19) and non‐responders ( n = 23) based on the number of residual pockets ≥ 5 mm with bleeding on probing at T6. Results TREM‐1 was higher in periodontitis than in gingivitis and health, and in periodontitis grade B than in gingivitis ( p < 0.05). PGLYRP1 and IL‐1β were higher in periodontitis and gingivitis compared to controls ( p < 0.01). All biomarkers discriminated periodontitis from health (AUC ≥ 0.9) with high sensitivity (82.1%–92.8%) and specificity (83.3%–88.9%). TREM‐1 differentiated periodontitis from gingivitis (AUC = 0.72) with high sensitivity (92.8%) but low specificity (58.1%). Baseline biomarkers did not predict treatment outcome (AUC ≤ 0.61), while T1 levels showed moderate potential (AUC ≥ 0.71). Conclusions Salivary TREM‐1 pathway biomarkers offer diagnostic value for periodontitis, are modulated by therapy but show limited ability to predict treatment outcome. Study Registration The study has been registered in ClinicalTrials.gov (ID: NCT06715176, 4 December 2024).