Water fluoridation (WF) is an important preventive program against dental caries. Recent Cochrane reviews reported only limited new scientific evidence of WF. This research aimed to provide contemporary evidence on the causal relationship between WF and oral health. A causal framework was used to ensure methodological rigour in repeated cross-sectional, population-based studies of randomly selected 5 to 14 y old children in Queensland, thereby enabling controlled difference-in-differences (DiD) analyses. The primary exposure was access to WF, defined as newly fluoridated (New-WF; areas that became fluoridated since 2010), never fluoridated (No-WF), or long-term fluoridated areas (Long-WF). The outcomes were dental caries experience (decayed, missing, or filled tooth surfaces) and prevalence in the primary and permanent dentition, collected by dental examiners who were uniformly trained and calibrated during both phases. The DiD estimands were the differences in changes in outcomes between New-WF and the control (No-WF), estimated from multivariable regression models. Data of 5,407 children during 2010–2012 and 7,718 children during 2022–2024 were collected. Variations in key confounders (area and individual socioeconomic factors) were controlled for using inverse probability of treatment weights. Dental caries among children in New-WF had consistently declined relative to the control groups. In the primary dentition, the New-WF children had a 1.40-fold (95% confidence interval [CI]: 1.08 to 1.80) reduction in caries experience and a 1.28-fold (1.00 to 1.67) reduction in caries prevalence, equivalent to 1.1 fewer affected tooth surfaces and a 10.8% lower prevalence. In the permanent dentition, reductions were smaller: a 1.32-fold (0.95 to 1.84) reduction in caries experience and a 1.04-fold (0.81 to 1.33) reduction in prevalence. These findings show that WF is effective in preventing dental caries in children when disease levels are low and other preventive programs are available. This controlled DiD study provides robust contemporary scientific evidence of the effects of WF on dental caries, strengthening WF as a public health policy.
Meckel’s cartilage (MC) is a transient scaffold for lower jaw development whose degradation is essential for normal mandibular morphogenesis, with defects leading to micrognathia or mandibular dysmorphogenesis. Here we investigate the timing and tissue interactions controlling MC degradation using transgenic mouse models, explant culture, and grafting experiments. Our results show that the initiation signal for degradation occurred in a window around embryonic day (E) 14.5, with induction of Runx2 and subsequent formation of hypertrophic cartilage. Loss of teeth in mouse mutants, removal of tooth germs ex vivo, or grafting tooth germs to ectopic sites did not affect degradation initiation, showing that developing teeth are neither necessary nor sufficient to initiate MC breakdown. In contrast, conditional neural crest deletion of Runx2 and, independently, loss of Msx1 prevented initiation of the degradation cascade despite retention of the dentary bone body in Msx1 mutants, identifying a signal from the dentary mesenchyme, rather than the tooth or the bone itself, as the extrinsic trigger. RUNX2 additionally played a second, cell-intrinsic role, driving the endochondral program once expressed within MC itself. Grafting experiments at E14.5–15 showed that proximal MC, outside the normal distal degradation zone, was not competent to respond to ectopic bone or tooth grafts at this stage. Separately, inhibition of vasculogenesis did not prevent chondrocyte hypertrophy but blocked subsequent cartilage clearance, implicating VEGF-dependent vasculature in a distinct, later step of chondroclast recruitment. Together, these findings define a 2-stage degradation cascade—extrinsic dentary mesenchyme-derived initiation followed by intrinsic RUNX2- and VEGF-dependent execution—and establish that neither teeth nor the physical presence of bone are sufficient to trigger MC breakdown.
Orthodontic tooth movement (OTM) requires coordinated remodeling of the periodontal ligament and alveolar bone, but the cellular architecture underlying this process in human tissues remains incompletely understood. We generated the first single-cell transcriptomic atlas of the human periodontal ligament during OTM by profiling control tissues and pressure- and tension-side tissues collected at days 3 and 7 following force application. Analysis of 65,032 cells identified 15 cell populations and revealed pronounced remodeling of stromal, immune, vascular, and neural compartments that varied by force direction and stage. Within the fibroblast compartment, we identified a CTHRC1 + fibroblast subset that was enriched on the pressure side at day 3 and exhibited heightened mechanotransduction, inflammatory signaling, and chemokine programs. TRPA1 was preferentially expressed in this subset, and computational perturbation, tissue validation, and pharmacologic inhibition supported its involvement in early remodeling on the pressure side. Ligand–receptor and functional analyses further implicated C3 as a downstream remodeling mediator linking regions rich in CTHRC1 + fibroblasts to monocyte recruitment and osteoclastogenic activity. In a mouse OTM model, systemic treatment with HC-030031 and local Trpa1 knockdown mediated by AAV9 under the Postn promoter reduced tooth movement, while HC-030031 also decreased osteoclast surface. Local C3a supplementation partially restored tooth movement during TRPA1 inhibition. These intervention data, with in vitro assays and tissue validation, support the involvement of TRPA1-associated signaling in a pressure-responsive stromal remodeling program and C3 as a potential downstream mediator of osteoclastogenic remodeling. These findings provide a human single-cell framework for periodontal remodeling during OTM and identify a pressure-responsive CTHRC1 + fibroblast population in which mechanosensitive TRPA1 contributes to osteoclastogenic remodeling on the pressure side.
Patients with oral cancer undergoing free flap reconstruction face significant surgical trauma, making the prevention of postoperative wound infection and the maintenance of oral microecological balance critical. This study systematically evaluated oral microbiome changes before and after surgery and assessed the effectiveness of postoperative oral irrigation using 2 different regimens. In an exploratory randomized controlled trial, 60 patients were assigned to receive oral irrigation with either bipolar water or a combination of hydrogen peroxide and sodium bicarbonate solution. Saliva and irrigation samples were collected at 7 time points, preoperatively and before and 5 minutes after oral irrigation on postoperative days 1, 4, and 7, and analyzed using specialized sequencing techniques to determine microbial abundance and diversity. Clinical outcomes, including wound infection rates and patient comfort, were also recorded. The results indicated that surgical treatment reduced the diversity of the oral microbiota and altered its composition. Before surgery, the oral cavity was dominated by potentially pathogenic taxa, which shifted toward oral resident microorganisms postoperatively. Continued oral irrigation promoted a transition from an unstable, anaerobic-enriched state toward a relatively stable community structure dominated by facultative anaerobes. While no differences were observed between the 2 groups regarding wound infection rates or microbial composition, the bipolar water group reported higher patient comfort and required shorter irrigation times. Furthermore, the bipolar water group maintained more stable microbial diversity, whereas the hydrogen peroxide group exhibited more pronounced fluctuations and higher fungal detection rates. In conclusion, surgery induces early microbial imbalance, but staged oral irrigation facilitates the stabilization of the oral microecosystem. Bipolar water is an effective alternative for perioperative care, helping to maintain microbial stability while improving the patient experience.
Hypomineralized second primary molars (HSPM) affect approximately 6.8% of children. Molars affected by HSPM mineralize between 20 wk of gestation and 15 to 17 mo of age. Experimental studies suggest that exposure to endocrine-disrupting chemicals, including di-2-ethylhexyl phthalate (DEHP) and bisphenol A (BPA), may disrupt enamel formation, but evidence in humans remains limited. This study investigates the association between prenatal exposure to individual phthalates, BPA, and their mixtures and the odds of HSPM in children. It was embedded in the Generation R study, a population-based prospective birth cohort in the Netherlands. Maternal urinary concentrations of BPA and 11 phthalate metabolites were measured each trimester. HSPM was diagnosed at age 6 y based on European Academy of Paediatric Dentistry criteria. Multivariate logistic regression models and Bayesian weighted quantile sum regression were used to assess individual and mixture associations, respectively. Among 1,160 mother–child pairs, 10.2% of children were diagnosed with HSPM. In single-exposure models, higher prenatal concentrations of monobenzyl phthalate (mBzBP) were associated with lower odds of HSPM (odds ratio [OR] = 0.76; 95% confidence interval [CI]: 0.59 to 0.97). Second-trimester exposure to DEHP metabolites showed a nonsignificant trend toward increased HSPM odds (eg, mEOHP OR = 1.15; 95% confidence interval [CI]: 0.91 to 1.45). Sex-specific associations were observed: higher BPA and phthalate concentrations were associated with lower likelihood of HSPM in girls (eg, BPA OR = 0.70; 95% CI: 0.50 to 0.98) and higher odds in boys ( p -interaction < 0.10). Mixture analyses showed a nonsignificant inverse association for overall prenatal exposure (OR = 0.84; 95% CI: 0.63 to 1.15), with mBzBP contributing most to the mixture. No overall association was observed for DEHP mixture, although sex-specific trends were consistent with single-exposure results. Prenatal exposure to phthalates and BPA may influence HSPM development. These findings highlight the need to consider early-life endocrine-disrupting chemical mixture exposure in HSPM etiology.
