The effect of chlorhexidine mouthwash on gingival health around stainless steel crowns in primary molars

Stainless steel crowns (SSC), widely used in pediatric dentistry, may cause gingivitis and discomfort. In this study, we investigated the effect of these crowns on gingival index (GI), periodontal probing depth (PPD), Oral Hygiene Index-Simplified (OHI-S), and the effect of chlorhexidine (CHX) mouthwash on reducing these indices in crowned teeth. A randomized assessor-blind controlled trial was conducted on 56 healthy children aged 4–9 years old requiring pulpotomy and SSC on mandibular primary molars. Patients were randomly divided into a control group (no mouthwash) and an intervention group (chlorhexidine mouthwash). In the second session, two weeks later, GI, OHI-S and PPD were measured in previously crowned and controlled teeth. Non-parametric tests Mann-Whitney and Wilcoxon were used to analyze OHI-S, PPD, and GI scores between groups. Comparing SSC-restored teeth between the intervention and control groups showed lower OHI-S and GI indices in the intervention group and this difference was significant (P = 0.004), (P=0.003), however PPD in crowned teeth did not differ significantly between the two groups (P> 0.05). In the control group, GI and PPD increased significantly in crowned teeth, while plaque accumulation remained unchanged. In contrast, the CHX group showed no significant differences between crowned and control teeth. Chlorhexidine mouthwash usage improved gingival health, and decreased plaque accumulation. Therefore, instructing patients to use mouthwash after SSC placement, particularly those with poor oral hygiene, is recommended. This trial was registered at the Iranian Registry of Clinical Trials (IRCT) on April 17, 2021, under registration number IRCT20210417050994N1.