Tooth-coloured alternatives (sliver nanoparticles) to silver fluoride for cavities in children

The intervention will involve a split-mouth design, where matched eligible teeth within the same participant will be randomly allocated to receive either conventional silver fluoride treatment using Riva Star Aqua™ (SDI Ltd, Bayswater, VIC, Australia) or one of the novel silver nanoparticle formulations. Participants will be randomised to one of two experimental formulation groups: Ag1 or AgL1. Within each participant, matched teeth will then be randomly allocated to receive either the control treatment or the allocated experimental formulation. Randomisation will be undertaken using a computer-generated randomisation sequence, and allocation will be documented in the participant’s study record. All treatments will be administered during a single dental appointment by a registered dentist trained in the study protocol. Riva Star Aqua™ is an ammonia-free, two-step silver fluoride system consisting of 38% silver fluoride followed by potassium iodide. Approximately 1 drop, approximately 10 µL per lesion site, will be dispensed into a disposable dappen dish and applied topically using a micro-applicator after isolation and gentle cleaning of the lesion. The silver fluoride solution will be applied for approximately 60 seconds, followed by potassium iodide application until the creamy white precipitate clears. The procedure for each lesion is expected to take approximately 5 minutes, with the total treatment appointment expected to last approximately 20–30 minutes depending on the number of lesions treated. Adherence to the intervention protocol will be monitored using standardised clinical record forms and documented in the participant’s dental records, including lesion isolation, application time, material used, and treated tooth surfaces. The novel silver nanoparticle formulations, Ag1 and AgL1, are experimental formulations containing silver nanoparticles prepared using different formulation approaches. Ag1 contains uncapped silver nanoparticles, while AgL1 contains citrate-capped silver nanoparticles. For all novel formulations, approximately 1–2 µL per lesion site will be applied topically using a sterile micro-applicator following standardised clinical protocols. Teeth will first be isolated and gently cleaned prior to application. The formulation will then be applied directly to the lesion surface and allowed to remain undisturbed for approximately 60 seconds. All applications will be performed by a registered dentist trained in the study protocol. The application procedure for each lesion is expected to take approximately 5 minutes, with the overall clinical appointment expected to last approximately 20–30 minutes depending on the number of lesions treated. Adherence to the intervention protocol will be monitored using standardised treatment documentation forms and participant dental records, including details of the formulation used, application duration, treated surfaces, and any adverse events or observations recorded at the time of treatment. Both the intervention and control treatments will be administered during the same dental appointment as part of the split-mouth study design. This approach will allow each participant to receive both the control treatment and one experimental formulation within the same appointment. The study will also investigate treatment acceptability and aesthetic perceptions of participants and/or parents through completion of a short questionnaire regarding treatment appearance, acceptability, comfort, and satisfaction following application of the materials. Participation in the questionnaire component will be voluntary and offered to all participants. The questionnaire will be completed immediately following treatment within the same appointment as the primary clinical intervention.