Comparing the Antiplaque Effects of Chlorhexidine Mouthwash and Essential Oil-Containing Mouthwash in Patients Reporting to Rehman College of Dentistry: A Randomized Clinical Trial

Dental plaque is one of the main causes of gum inflammation and periodontal (gum) disease. While brushing and flossing remain the primary way to remove plaque, mechanical cleaning alone often cannot fully reach all tooth surfaces. As a result, chemical mouthwashes are commonly recommended as an additional way to control plaque.

Chlorhexidine gluconate mouthwash is considered one of the most effective plaque-control products because it kills a broad range of bacteria and stays active in the mouth for an extended period. However, longer-term use has been associated with side effects such as tooth staining and taste changes. Mouthwashes containing essential oils (plant-derived antibacterial ingredients such as thymol and menthol) are often used as a gentler alternative, though their plaque-reducing effect compared to chlorhexidine has varied across previous studies.

This randomized clinical trial was conducted at the Department of Periodontics, Rehman College of Dentistry, Peshawar, from February 2026 to August 2026. Sixty participants aged 15-25 years with gingivitis (gum inflammation without bone or attachment loss) were enrolled and divided into two equal groups of 30. Group I used a 0.2% chlorhexidine gluconate mouthwash twice daily, and Group II used an essential oil mouthwash twice daily, both for a period of three months. Participants were selected using a non-probability consecutive sampling method, and all received professional teeth cleaning (scaling and polishing) before starting the study, followed by a 10-day period to allow a consistent starting point for plaque measurement.

Plaque levels were measured using the Silness and Löe Plaque Index, a standard scoring method that assesses plaque on six specific teeth at the start of the study and again after three months. The dental examiner who scored the plaque levels was not told which mouthwash each participant had been using, to reduce bias in the assessment. All participants were given the same basic oral hygiene instructions (brushing twice daily), so that any difference in outcomes could be more clearly linked to the mouthwash itself.

Researchers compared plaque scores, percentage reduction in plaque, participant compliance with the assigned mouthwash routine, and any reported side effects between the two groups. Statistical methods included ANCOVA to compare three-month plaque scores while accounting for each participant's starting plaque level, along with t-tests and chi-square tests for other comparisons.