Does chlorhexidine mouthwash, with an anti-discoloration system, reduce tooth surface discoloration without losing its efficacy? A systematic review and meta-analysis

Objectives: To investigate whether chlorhexidine mouthwash (CHX-MW), with an anti-discoloration system(ADS), is effective in preventing extrinsic tooth surface discoloration. Additionally, this paper seeks to evaluate whether CHX combined with an ADS maintains its efficacy with respect to reducing plaque and gingivitis scores. Material and methods: MEDLINE-PubMed and Cochrane-Central were searched up to October 2018 to identify eligible studies. Papers evaluating the effect of CHX-MW+ADS compared to CHX without an ADS were included. A descriptive analysis and when feasible a meta-analysis was performed. Results: Screening resulted in 13 eligible publications, presenting 16 comparisons. Six of these evaluated the MW in a non-brushing model and ten as an adjunct to toothbrushing. A descriptive analysis demonstrated that the majority showed no differences in bleeding, gingivitis and plaque scores. This was confirmed by the meta-analysis. In non-brushing experiments, the difference-of-means (DiffM) for plaque scores was 0.10 (P = 0.45, 95%CI: [−0.15; 0.34]) and for the gingival index 0.04 (P = 0.15,95%CI: [−0.02; 0.11]). The DiffM in brushing studies for plaque scores was 0.01 (P = 0.29, 95%CI: [−0.01; 0.02]) and for the gingival index 0.00 (P = 0.87,95%CI: [−0.05; 0.06]). With respect to staining scores, the meta-analysis revealed that in non-brushing studies, the standardized mean difference was 3.19 (P = 0.0005,95%CI: [−3.98; −1.41]) while in brushing studies, the DiffM was 0.12 (P = 0.95,95%CI: [−3.32; 3.55]). Conclusion: There is moderate quality evidence from non-brushing studies that the addition of an ADS to CHX-MW reduces tooth surface discoloration and does not appear to affect its properties with respect to gingival inflammation and plaque scores. In brushing studies, there is also moderate quality evidence that ADS does not affect the anti-plaque and anti-gingivitis efficacy of CHX. The majority of comparisons and the meta-analysis including these indicate no significant effect of ADS on tooth staining in situations where the mouthwash is used in addition to toothbrushing