Takashi Ono

1. Orthodontic and dentofacial orthopaedic treatments primarily aim to establish functional occlusion, enhance facial aesthetics, and maintain stomatognathic stability. However, dental medicine inc...

Objective: This study aimed to clarify the relationship between stromal cell‑derived factor 1 (SDF‑1) and osteoblast‐related responses in periodontal ligament (PDL) during orthodontic tooth movement (OTM) after tooth extraction, based on the hypothesis that local inhibition of SDF‑1/C‑X‑C chemokine receptor type 4 (CXCR4) signaling with the CXCR4 antagonist AMD3100 would attenuate osteoblast differentiation and alveolar bone remodeling during OTM. Methods: Thirty‐six 6‐week‐old Wistar/Sprague–Dawley male rats were randomly divided into control and experimental groups. After the extraction of the maxillary left first molar, the maxillary left second molar (M2) was moved mesially with a 10‐gf force following the local injection of phosphate‐buffered saline or AMD3100 into the buccal and palatal gingiva adjacent to the M2 in the control and experimental group, respectively. Micro‐computed tomography was performed to assess tooth movement and alveolar bone changes. Histological and immunohistochemical analyses were performed to evaluate periodontal tissue morphology and the percentages of SDF‐1‐, CXCR4‐, RUNX2‐, and BGLAP‐positive cells on the tension side of the PDL. Quantitative reverse transcription PCR was used to assess expression levels of SDF‐1, CXCR4, RUNX2, and BGLAP. Results: OTM distance and mesial tilt angle were significantly reduced in the experimental group. RT‐PCR showed that SDF‐1, CXCR4, and RUNX2 expression levels were significantly downregulated from Day 1 through Day 7, whereas BGLAP expression was significantly decreased only on Day 1. Immunohistochemical analysis of the tension side of the PDL demonstrated significantly reduced SDF‐1‐ and CXCR4‐positive cells on Day 3 and RUNX2‐positive cells on Day 7 in the experimental group. In contrast, the BGLAP‐positive cells did not differ significantly at any time point. Conclusion: Local inhibition of SDF‐1/CXCR4 signaling reduced OTM and altered early alveolar bone remodeling after tooth extraction. The combined gene expression and immunohistochemical findings suggest that the SDF‐1/CXCR4 axis may contribute to osteoblast differentiation, particularly through RUNX2‐related responses during the early phase of OTM. Trial Registration: Not applicable.

Background/Objectives: We evaluated whether resin infiltration treatment of demineralized enamel improves shear bond strength (SBS). Methods: Thirty permanent bovine incisor teeth were assigned randomly into three groups (n = 10 per group): control group, demineralized enamel pretreated with ICON^® resin infiltrant (Exp1 group), and demineralized enamel without pretreatment (Exp2). Demineralization was induced using a pH 4.5 solution for 21 days and was monitored using swept-source optical coherence tomography on days 0, 7, 14, and 21. The lesion depth (LD) was quantified and evaluated using ImageJ software. In the Exp1 group, ICON^® was applied prior to bracket bonding; no pretreatment was applied in the Exp2 group. In all groups, brackets were bonded using Super-Bond/Clear fluoride-free self-cure adhesive resin (4-META/MMA-TBB, Sun Medical) following Phosphoric acid (65%; Red Activator, Sun Medical). After debonding, enamel surfaces were evaluated to determine the adhesive remnant index (ARI). Results: No significant difference (p = 0.631) was noted in LD between Exp1 and Exp2 groups. The SBS values significantly differed (p < 0.05) between the control (4.1 ± 1.0 MPa) and Exp1 (5.5 ± 1.4 MPa) groups and between the Exp1 and Exp2 (3.8 ± 1.3 MPa) groups. However, SBS did not differ significantly between the control and Exp2 groups. Furthermore, ARI scores showed no significant difference between the control and Exp1 groups, whereas the Exp2 group recorded significantly elevated ARI scores relative to the control group (p = 0.0127). Conclusions: These findings suggest that resin infiltration with ICON^® may improve bracket adhesion on demineralized enamel.

Orthodontic treatment facilitates improvements in aesthetics, occlusion, and speech, thereby improving overall oral health and quality of life [1–3]. Demand for adult orthodontic treatment has incr...

Background/Objectives: Obstructive sleep apnea (OSA) during pregnancy may reduce maternal oxygenation, cause sleep fragmentation, and influence offspring development. This pilot study explored potential associations between OSA during pregnancy and child outcomes at age 3. Methods: Pregnant women aged 23–48 years who underwent home sleep apnea testing (HSAT) at 28–32 weeks of gestation between June 2021 and July 2025 were enrolled. OSA was defined as an apnea–hypopnea index (AHI) ≥ 5. Mothers and children were prospectively followed until the child reached 3 years of age. Children’s developmental levels (motor, cognitive/adaptive, language/social, and total) were evaluated using the New K-Type Developmental Test. Anthropometric measures (height, weight, and head circumference) and dental occlusion were also assessed. Correlations between the maternal AHI and developmental indices were examined. Results: Thirty-four women, including six with OSA, completed the follow-up assessment. No significant differences were observed in children’s physical growth or occlusion between the OSA and non-OSA groups. The maternal AHI showed a negative tendency with the total developmental index and the cognitive/adaptive and language/social domains. One participant with severe OSA (AHI = 69.3) showed markedly lower developmental scores, suggesting a possible dose-dependent trend rather than a definitive threshold. Given the small number of OSA cases and the influence of a single severe case, these findings should be interpreted cautiously as preliminary and descriptive. Conclusions: OSA during pregnancy may be associated with differences in early childhood development. The findings highlight the importance of maternal sleep health awareness and feasible screening approaches, such as HSAT, during pregnancy.