Staining of dental plaque and intraoral photography
rigidity
DENTAL PLAQUE
The participants attended the Faculty of Dentistry on two occasions during the development of phase 1 and once in phase 2. In the first appointment for phase 1 (day 0), we performed ultrasound scaling and polishing with a brush/cup and polishing pastes. Dental floss or interproximal brushes were used where appropriate for the interproximal areas. In this way, all the participants had an initial level of dental plaque close to zero at the start of the experiment. A series of rinses was then employed to stain the dental plaque, with sodium fluorescein as the developer:
One rinse for 10 s with 20 ml of phosphate buffer.One rinse for one minute with 15 ml of 1240 parts per million (ppm) fluorescein in a phosphate buffer.Three rinses for 10 s with 25 ml of phosphate buffer.At both the second appointment in phase 1 (day 4) and the only one in phase 2 (day 8), the same rinsing protocol as that described above was performed to stain the dental plaque with sodium fluorescein.On days 0, 4, and 8, the participants in each mouthwash test group (i.e., test group A or B) performed the sodium fluorescein rinse protocol before intraoral photographs were taken under ultraviolet light using our self-designed intraoral image replication device (number of patent registration: 2572333). This has been designed based on the following requirements that guarantee the positional standardisation of all its elements: the rigidity and stability of the device as a whole; the option to adjust and spatially fix the attachments to enable it to be adapted to any individual; the capacity to register its position numerically; and the ease of handling and transport.Three intraoral photographs were taken of each subject at each appointment: one frontal (from canine to canine) and two lateral (from the premolar to the first molar, including the upper and lower sectors) (Fig. 
Photographs were taken under ultraviolet light on days 0, 4, and 8 in one patient of test group A (left) and one patient of test group B (right)