The effect of low-level laser therapy as an adjunct to non-surgical periodontal treatment on gingival crevicular fluid levels of transforming growth factor-beta 1, tissue plasminogen activator and plasminogen activator inhibitor 1 in smoking and non-smoking chronic periodontitis patients: A split-mouth, randomized control study.

BACKGROUND AND OBJECTIVE: This study aimed to investigate the effects of low-level laser therapy (LLLT) as an adjunct to scaling and root planing (SRP) on smoking and non-smoking patients with chronic periodontitis. MATERIAL AND METHODS: The study was conducted using a split-mouth design with 30 patients with chronic periodontitis (15 smokers, 15 non-smokers) and 30 healthy individuals matched for age, sex and smoking status as controls. Groups were constituted as follows: Cp+SRP+Sham: non-smokers with chronic periodontitis treated with SRP; Cp+SRP+LLLT: non-smokers with chronic periodontitis treated with SRP+LLLT; SCp+SRP+Sham: smokers with chronic periodontitis treated with SRP; SCp+SRP+LLLT: smokers with chronic periodontitis treated with SRP+LLLT; C: control group comprised of periodontally healthy non-smokers; SC: control group comprised of periodontally healthy smokers. LLLT was first applied on the same day as SRP and again on days 2 and 7 after SRP treatment. Clinical parameters were recorded before non-surgical periodontal treatment (baseline) and on day 30. Gingival crevicular fluid samples were collected before periodontal treatment (baseline) and during follow-up visits on days 7, 14 and 30. Gingival crevicular fluid transforming growth factor (TGF)-beta1, tissue plasminogen activator (tPA) and plasminogen activator inhibitor 1 (PAI-1) levels were measured using enzyme-linked immunosorbent assay. RESULTS: All clinical parameters showed significant reductions between baseline and day 30 following SRP treatment in both the LLLT and sham groups (P<.001). No significant differences were observed between the LLLT and sham groups of either the smokers or non-smokers (P>.05). Gingival crevicular fluid PAI-1 levels decreased significantly in the SCp+SRP+sham and SCp+SRP+LLLT groups (P<.05), and gingival crevicular fluid tPA levels decreased significantly in the Cp+SRP+sham, Cp+SRP+LLLT and SCp+SRP+LLLT groups (P<.05). Gingival crevicular fluid TGF-beta1 levels decreased significantly in all treatment groups (P<.05). Although no significant differences were found between the gingival crevicular fluid PAI-1, tPA and TGF-beta1 levels of the LLLT versus sham groups (P>.05) at any of the time points measured, both LLLT groups showed significant reductions in tPA/PAI-1 ratios over time. CONCLUSION: Within the limits of this study, LLLT may be understood to play a role in the modulation of periodontal tissue tPA and PAI-1 gingival crevicular fluid levels, particularly in smoking patients with chronic periodontitis, and may thus be recommended as an adjunct to non-surgical periodontal treatment.