Changes in white spot lesions following post-orthodontic weekly application of 1.25 per cent fluoride gel over 6 months-a randomized placebo-controlled clinical trial. Part II: clinical data evaluation

Background: White spot lesions (WSL) frequently occur as side-effect of multibracket appliance treatment. The clinical effects of local fluoridation on post-orthodontic WSL and oral health development are however inconclusive. Objective: In vivo monitoring of clinical WSL and oral health changes in response to weekly 1.25 per cent fluoride gel application after multibracket appliance treatment. Trial design: Randomized, single-centre, double-blind, parallel-group, placebo-controlled study. Participants: Patients with not less than 1 WSL (modified score 1 or 2) on not less than 1 upper front teeth after debonding. Interventions: Professional fluoride/placebo gel application during weeks 1-2; self-administered home application (weeks 3-24). Outcomes: Clinical evaluation of WSL index, lesion activity, plaque index, gingival bleeding index, and decayed, missing, and filled teeth index as well as saliva buffer capacity and stimulated salivary flow rate (T0-T5). Randomization: Random assignment to test (n = 23) or placebo group (n = 23) using a sequentially numbered list (random allocation sequence generated for 50 subjects in 25 blocks of 2 subjects each). Recruitment: The clinical study duration lasted from March 2011 to September 2013. Blinding: Unblinding was performed after complete data evaluation. Numbers analysed: Intention-to-treat analysis set comprised 39 participants (test: n = 21, placebo: n = 18). Outcome: No clinical parameter except stimulated salivary flow rate (fluoride group: 1.1 ml/min, placebo group: 0.74 ml/min; P = 0.022) showed a statistically significant group difference after 24 weeks. Harms: Several adverse events occurred similarly frequent in both groups; none was classified as possibly related to the study product. Limitations: The number of dropouts was higher than expected and the socio-economic status was not assessed. Furthermore, the unknown level of compliance during the home application phase must be considered as limitation. Conclusion: Based on the results of this study, no clinical effect of post-orthodontic high-dose fluoride treatment on WSL and oral health changes could be detected. Registration: The study was registered with ClinicalTrials.gov (Identifier: NCT01329731). Protocol: The protocol wasn't published before trial commencement.