Goals of this research are: 1. To compare the plaque index in orthodontic patients treated with different antibacterial agents (photodynamic therapy, tricalcium phosphate varnish with 5% NaF, chlorhexidine varnish) before insertion of a fixed orthodontic appliance (T0), 6 weeks (T1), 12 weeks (T2) and 18 weeks later (T3); 2. To compare the bacteriological composition of supragingival plaque using the mass spectrometry in orthodontic patients treated with different antibacterial agents before insertion of a fixed orthodontic appliance (T0), 6 weeks (T1), 12 weeks (T2) and 18 weeks later (T3); 3. To compare the bacteriological composition of subgingival plaque using polymerase chain reaction in orthodontic patients treated with different antibacterial agents before insertion of a fixed orthodontic appliance (T0) and 18 weeks later (T3); 4. To compare the gingival index in orthodontic patients treated with different antibacterial agents before insertion of a fixed orthodontic appliance (T0), 6 weeks (T1), 12 weeks (T2) and 18 weeks later (T3); 5. To compare the occurrence of white spot lesions in orthodontic patients treated with different antibacterial agents before insertion of a fixed orthodontic appliance (T0) and 18 weeks later (T3).
This study hypothesizes that photodynamic therapy is just as effective in reducing plaque accumulation, reducing bacteria in supragingival and subgingival plaque, preventing gingival inflammation and preventing initial carious lesions (white spot lesions) in orthodontic patients as tricalcium phosphate varnish with 5% NaF and 1% chlorhexidine varnish.
Participants (40 orthodontic patients at the Department of Orthodontics, University Hospital Centre Zagreb, Croatia) will be randomly assigned to one of four groups. Randomization will be performed before the recruitment using software for randomization (Research Randomizer; permuted blocks randomization). Outcome assessor will be blinded, while participants and care providers will be aware of the group allocation.
Group of participants (n=10) allocated to the first group will receive photodynamic therapy which consists of toluidine blue based dye (155 mg/mL) and 660 nm diode laser. Participants (n=10) allocated to the second group will receive tricalcium varnish with 5% NaF which will be applied according to the manufacturer's recommendations. Group of participants (n=10) allocated to the third group will receive chlorhexidine varnish which will be applied according to the manufacturer's recommendations. All interventions will be performed right after the placement of a fixed orthodontic appliance (T0), 6 weeks (T1) and 12 weeks (T2) later. The fourth group (n=10) will be the negative control which means that participants will not receive any intervention.
Primary outcome measures: assessment of dental plaque accumulation using plaque index and assessment of the bacteriological composition of supragingival plaque using mass spectrometry. Secondary outcome measures: assessment of the bacteriological composition of subgingival plaque using the polymerase chain reaction, assessment of gingival condition using the gingival index and diagnosis of white spot lesions on intraoral photographs.
