Effect of a mouthwash containing green tea as adjunct to step 1 therapy of perio-implant mucositis on clinical, microbiological and patient-reported outcomes

Abstract

Objectives
This thesis examined the effects of green tea mouthwash (GTM) versus chlorhexidine(CHX) on periodontal health and oral microbiome in peri-implant mucositis patients. It evaluated how the disease affects their oral health quality of life (OHQoL). It also compared green tea extracts (GTE) with other antimicrobials in controlling Porphyromonas gingivalis, a periodontal pathogen, to assess the potential of herbal alternatives to conventional antiseptics. Additionally, the study explored whether an educational video could improve patients' understanding of dental implant care and maintenance.

Methods
A systematic review and meta-analysis were conducted by searching for relevant randomised controlled trials (RCT) and critically appraising them. The meta-analysis compared standard mean values and confidence intervals. Patients with peri-implant mucositis were recruited based on specific criteria from two clinics and enrolled in a triple-blinded, randomised study with a one-year follow-up. Periodontal pocket depth(PPD), modified plaque scores (MPS%), modified bleeding scores (MBS%), and OHQoL were measured at each appointment, with plaque samples collected at baseline and two weeks.

DNA from plaque samples underwent Illumina MiSeq. The periodontal pathogen, P.gingivalis, was also grown and treated with GTE, GTM, CHX, and vancomycin (VCN)to evaluate their antimicrobial effects on planktonic cells.

Results
The systematic review identified 39 clinical trials that evaluated the use of tea as an intervention in various oral health conditions, including periodontal disease, oral surgery, mucosal lesions, caries, halitosis, and xerostomia. A meta-analysis of three high-quality studies showed low heterogeneity (I² = 13% for Plaque Index (PI) and I² = 0% for Gingival Index (GI)). GTM demonstrated statistically significant effects on PI compared to CHX, though there was no significant difference for GI.

In the RCT, 41 patients with peri-implant mucositis were recruited to achieve a 95% statistical power. Between baseline and two weeks, significant reductions in MPS%,MBS%, and PPD were observed in both the GTM and CHX groups around dental implants, with GTM showing MPS% reductions of 33.10 (12.45–50.00; p<0.0001) and CHX showing reductions of 33.30 (25.00–40.70; p<0.0001). Similar reductions were recorded for MBS% (p<0.0001) and PPD (p<0.0001) in both groups. Around natural teeth, GTM also showed reductions from baseline to two weeks in MPS% (38.90; 22.10–47.20, p<0.0001), MBS% (16.70; 8.30–25.00, p<0.0001), and PPD (0.24; 0.00–0.51,p=0.0012). CHX yielded similar results, with significant reductions in MPS%, MBS%, and PPD from baseline (p<0.0001).

No significant differences in OHQoL scores were observed between the two groups after2 weeks (Median GTM vs CHX baseline = -3.412 and 2 weeks = -5.979, p>0.9999). Similarly, watching an educational video on dental implants did not cause a significant improvement in understanding (p>0.05). The in-vitro study showed no significant change in oral microbiome composition before and after mouthwash use. However, P. gingivalis growth was inhibited by GTM and CHX, and reduced by 32.25 µg/ml of GTE.

Conclusion
GTM is as effective as CHX in improving gingival health around dental implants and teeth alongside a periodontal treatment but had no impact on the OHQol in patients diagnosed with peri-implant mucositis at any time point. Furthermore, green tea can bean effective antimicrobial agent in improving periodontal-related conditions and diseases by reducing PI and the growth of P. gingivalis. Similarly, the use of an educational video can enhance dental patients' knowledge and awareness about their dental implants and their' maintenance.

Date of Award	Mar 2025
Original language	English
Supervisor	Paul Mc Carron (Supervisor) & Nigel Ternan (Supervisor)