TREM-1 Pathway in Predicting Treatment Outcomes in Periodontitis

This study investigated modulations in salivary triggering receptor expressed on myeloid cells (TREM)-1, peptidoglycan recognition protein 1 (PGLYRP1) and interleukin (IL)-1β levels between healthy, gingivitis and periodontitis patients, and in response to non-surgical periodontal treatment. Systemically healthy, non-smokers with gingivitis (n=31), stage III periodontitis (grade B: n=34, grade C: n=24) and periodontally-healthy controls (n=34) were recruited. Periodontitis patients (n=45) underwent non-surgical periodontal treatment. Saliva was collected at baseline (T0, all groups), and three times (T1, T3 and T6) post-treatment (periodontitis groups only). Salivary biomarkers and total protein were measured using commercial assays.

Study population and design: For this study, systemically healthy, non-smokers with gingivitis (n = 31), stage III, grade B periodontitis (n = 34), stage III, grade C periodontitis (n = 24), and periodontally healthy controls (n = 34) were recruited at the Department of Periodontology, School of Dentistry, Aydın Adnan Menderes University, Aydın, Turkey.

Clinical examination and saliva collection: All participants were clinically examined at baseline (T0) and whole mouth plaque (PI) and gingival index (GI), probing depth (PD), bleeding on probing (BOP) and clinical attachment loss (CAL) were measured. Prior to clinical examinations, unstimulated whole saliva was collected from all participants at baseline (T0). Additionally, saliva sampling and clinical examinations were performed for all periodontitis patients (grade B and C) one (T1), three (T3) and six (T6) months after non-surgical periodontal treatment.

Non-surgical periodontal treatment protocol: The patients underwent non-surgical periodontal therapy including quadrant-based scaling and root planning (SRP) using ultrasonic instruments and periodontal curettes until the root surfaces were visibly and tactically clean and smooth. All participants were given routine oral hygiene instructions and asked to abstain from any anti-inflammatory drugs, antibiotics, or mouthwashes containing chlorhexidine throughout the study period. At every visit, oral hygiene instructions were reinforced, and the sites that did not respond to treatment at T1 underwent additional re-instrumentation at T3 and T6. While non-surgical treatment efficacy is often reported in terms of mean values of PD reduction and CAL gain, these metrics may not fully capture treatment success or periodontal stability.

Triggering receptor expressed on myeloid cells (TREM)-1, peptidoglycan recognition protein 1 (PGLYRP1) and interleukin (IL)-1β immunoassays and total protein determination: 249 saliva samples were included for the analysis of TREM-1, PGLYRP1 and IL-1β. Levels of those cytokines in saliva were measured by commercial enzyme-linked immunosorbent assays according to manufacturer's instructions. Total protein levels in saliva were measured by the BCA Protein Assay according to the manufacturer's guidelines.

Statistical analysis: Group comparisons were performed with Mann-Whitney, Kruskal-Wallis with Dunn-Bonferroni post-hoc, or Chi-square tests, whenever appropriate. Group comparisons before and after treatment were performed with Friedman with Dunn-Bonferroni post-hoc test. Differences were deemed statistically significant at p ≤0.05.

Eligibility Criteria:
Inclusion Criteria:

* systemically healthy
* non-smoker individuals

Exclusion Criteria:

* pregnancies or lactation
* to exposure to antibiotics or any other drugs that were known to affect periodontal conditions over the past 6 months prior to recruitment.
* to receive previous surgical/nonsurgical periodontal treatment during the previous 12-months.