Abstract
Recent evidence for a significant interference of microcrystalline hydroxapatite (HAP) particles with re- and demineralisation processes at the tooth-biofilm interface suggested, that they may be promising candidates for efficacious caries prevention. This multicenter randomized controlled non-inferiority trial evaluated the impact of the 2 x daily use of a HAP dentifrice without fluoride on the progression of enamel caries in adolescent caries-risk patients subjected to orthodontic therapy, with a fluoridated AmF/SnF dentifrice serving as a positive control. Primary study outcome was the occurrence of enamel caries lesions ≥ ICDAS (International Caries Detection and Assessment System) code 1 around orthodontic brackets on the vestibular surfaces of teeth 15-25 within the 168 days observation period. Secondary study outcomes were the occurrence of enamel caries lesion ≥ ICDAS code 2, Plaque Index (PlI) and Gingival Index (GI). Out of 150 recruited patients, 147 were included in the intent to treat analysis (ITT); 133 finished the study per protocol (PP). PP data analysis revealed the occurrence of enamel caries ≥ ICDAS code 1 in 54.7% of the HAP group patients compared to 60.9% of the fluoride control. In the ITT analysis the corresponding numbers were 56.8% (HAP) and 61.6% (control). Non-inferiority testing of the ITT as well as the PP data set proved that the caries preventive efficacy of the HAP dentifrice was not inferior to the protection provided by the fluoridated AmF/SnF control. Regarding all assessed secondary outcomes (enamel caries ≥ ICDAS code 2, GI, PlI) no significant differences between both experimental groups were observed. Within the restraints set by design and study population of this trial microcrystalline HAP as ingredient of toothpaste may thus be regarded a promising supplement to fluorides in clinical caries prevention (ClinicalTrials.gov: NCT02705456).