Comparison of the Clinical and Microbiological Effects of CHX and HOCl Containing Mouthwashes

Participants used 0.02% hypochlorous acid mouthwash for four days, followed by a 14-day washout period, and then 0.2% chlorhexidine gluconate mouthwash for four days. Each mouthwash was used twice daily, with 10 mL rinsed for one minute.

Rinse with 10 mL for one minute, twice daily for four days.

Rinse with 10 mL for one minute, twice daily for four days.

Participants used 0.2% chlorhexidine gluconate mouthwash for four days, followed by a 14-day washout period, and then 0.02% hypochlorous acid mouthwash for four days. Each mouthwash was used twice daily, with 10 mL rinsed for one minute.

Rinse with 10 mL for one minute, twice daily for four days.

Rinse with 10 mL for one minute, twice daily for four days.

Dental plaque was assessed using the modified Silness and Löe Plaque Index at six sites per tooth. Each site was scored from 0 (no plaque) to 3 (abundant plaque). Mean scores were calculated for the full mouth and 12 anatomical regions and compared between the HOCl and CHX treatment periods. Mean scores range from 0 to 3; higher scores indicate greater plaque accumulation.

Total culturable bacterial counts were measured in supragingival plaque samples collected from molar teeth and expressed as colony-forming units per milliliter (CFU/mL). Counts were compared between the HOCl and CHX treatment periods.

Bleeding was assessed at six sites per tooth using a periodontal probe. Sites showing bleeding within 30 seconds after probing were recorded as positive. BOP was calculated as the number of bleeding sites divided by the total number of examined sites, multiplied by 100. Full-mouth and regional percentages were calculated. Scores range from 0% to 100%; higher values indicate more gingival bleeding.

Extrinsic tooth staining was assessed in four regions on each buccal and lingual/palatal tooth surface. Intensity was scored from 0 to 3. Area was scored from 1 to 3 only when intensity was 2 or 3, using the region-specific criteria of Macpherson et al. (2000). For intensity scores of 1, the intensity × area value was defined as 1. The participant-level MSI was calculated by averaging these values across examined regions, with a range of 0-9. Higher scores indicate greater staining.

At the end of each treatment period, participants completed a five-item questionnaire assessing mouthwash taste, effects on taste perception, perceived tooth cleanliness, perceived tooth discoloration, and nausea associated with mouthwash use. Each item was rated as 1 (poor), 2 (moderate), or 3 (good). Higher scores indicate a more favorable participant rating. Each item was evaluated separately.

After completing both treatment periods, participants indicated which of the two mouthwashes they preferred. The number of participants preferring each mouthwash was recorded.