Objective: Preservation of the periodontal ligament (PDL) is vital to the success of tooth autotransplantation (TAT). Increased PDL volumes and facilitated tooth extraction have been observed upon orthodontic preloading. However, it is unclear whether any changes occur in the expressions of bone biomolecules in the increased PDL volumes. This study aimed to determine the expressions of runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), receptor activator of nuclear factor kappa-B ligand (RANKL), and osteoprotegerin (OPG) in PDL upon preloading. Methods: Seventy-two premolars from 18 patients were randomly assigned to experimental groups that received a leveling force for 1, 2, or 4 weeks or to a control unloaded group. Following extraction, PDL volumes from 32 premolars of eight patients (21.0 ± 3.8 years) were evaluated using toluidine blue staining. The expressions of the biomolecules in the PDL from 40 premolars of ten patients (21.4 ± 4.0 years) were analyzed via immunoblotting. Results: The median percentage of stained PDL was significantly higher at 2 and 4 weeks after preloading than in the unloaded condition (p < 0.05). The median RUNX2 and ALP expression levels were significantly higher at 2 and 4 weeks after preloading than in the unloaded condition (p < 0.05), whereas the median RANKL/OPG ratios were significantly higher at 1 and 4 weeks after preloading (p < 0.05). Conclusions Orthodontic preloading for 4 weeks enhances PDL volumes as well as the expressions of RUNX2, ALP and the RANKL/OPG ratio in the PDL, suggesting this loading period is suitable for successful TAT.

Objective: This study aimed to determine and quantify the presence of the active components in Thai propolis extracts using high performance liquid chromatography (HPLC). Moreover, the anti-caries potential of Thai propolis extract and its active ingredients were tested. Methods: Fifty milligrams of Thai propolis were extracted using either 100%, 90%, 80%, or 70% ethanol and subsequently analyzed using HPLC with a mobile phase gradient system of 10-100% acetonitrile in 0.05% aqueous ortho-phosphoric acid, flow rate of 0.8 mL/min, and detection wavelength of 280 nm. Varying concentrations of Thai propolis extracts as well as four active ingredients were subjected to agar well diffusion test against the growth of Streptococcus mutans (S. mutans) or Lactobacillus caseii (L. caseii). Results: The concentrations of the four active ingredients: vicenin-2, vitexin, apigenin, and cinnamic acid, were significantly affected by ethanolic concentrations. The chromatographic peaks of all active ingredients from 70% and 80% ethanolic extracts appeared more defined, as compared to those which used higher concentrations of ethanol for extraction. Except for the absolute ethanolic extract, all of the examined propolis extracts, as well as its active ingredients inhibited both S. mutans and L. caseii. Conclusions Thai propolis extracts contain vicenin-2, vitexin, apigenin, and cinnamic acid as part of its active ingredients. These were found to be significantly affected by the increase in ethanol during its extraction. The presence of these active ingredients might have contributed to the anti-caries potential of Thai propolis extracts.
flavonoids ; chromatography, high performance liquid