Type 2 diabetes accelerates jawbone loss and causes tooth loss

Type 2 diabetes (T2D) is a chronic metabolic disorder whose global burden continues to rise. Beyond its systemic effects, T2D compromises skeletal health and markedly worsens loss of alveolar bone—the bone that anchors teeth—leading to tooth loosening, increased mobility, and eventual tooth loss. Diabetic patients also face a substantially higher risk of periodontitis, a chronic inflammatory disease that further disrupts bone homeostasis. The interplay among diabetes, periodontitis, and alveolar bone loss accelerates disease progression and threatens oral health. Although parathyroid hormone (PTH) and its analogs have shown promise for alveolar bone regeneration and periodontal healing in preclinical models, whether they can restore alveolar bone in established T2D, and which cells mediate their effects, remained unexplored. Because of these gaps, in-depth research into the cellular and molecular mechanisms of PTH receptor signaling in diabetic alveolar bone is needed.

In a study published (DOI: 10.1038/s41368-026-00470-3) in the International Journal of Oral Science on 29 October 2026, researchers at Indiana University School of Medicine and the University of Arkansas for Medical Sciences investigated the effects of PTH and abaloparatide (ABL) on alveolar bone remodeling in a mouse model of established T2D induced by high-fat diet and streptozotocin (STZ). Using micro-computed tomography (μCT), histological staining, immunofluorescence, and conditional knockout mice lacking the PTH/PTHrP receptor (PTH1R) in DMP1-Cre-positive cells, the team examined how these agents affect bone formation and resorption in the periodontium.

The researchers found that in non-diabetic mice, PTH and ABL stimulated both bone formation and resorption, resulting in no net change in alveolar bone mass. In contrast, in T2D mice, both agents significantly increased bone volume and restored alveolar bone height toward non-diabetic levels. Mechanistically, PTH and ABL suppressed sclerostin and Dickkopf-1 (Dkk-1) in osteocytes, activating Wnt signaling and increasing RUNX2 expression in periodontal ligament (PDL) cells. Notably, the drugs did not further increase the already elevated osteoclast numbers in diabetic mice, whereas they did promote osteoclastogenesis in non-diabetic animals. Using DMP1-Cre;PTH1R conditional knockout mice, the team showed that PTH1R signaling in DMP1-Cre-positive cells—primarily osteocytes—is essential for the anabolic effects but dispensable for the pro-resorptive effects, which are instead driven by PTH1R signaling in DMP1-Cre-negative marrow cells through upregulation of receptor activator of nuclear factor kappa-B ligand (RANKL) and suppression of osteoprotegerin (OPG). This cell-type-specific duality helps explain why the drugs produce net bone gain only under diabetic conditions.

The authors said their findings reveal a dual mechanism of PTH1R signaling in oral bone remodeling, in which osteocytes drive bone formation while marrow cells drive resorption. They said this uncoupling of anabolic and catabolic responses has significant implications for tailoring PTH1R-based therapies for diabetic bone disease, and that bone anabolic regimens using PTH1R ligands could help restore alveolar bone, enhance tooth stability, and promote oral health in diabetes. They added that further studies are needed to dissect these distinct regulatory pathways and guide optimization of PTH pathway-targeting therapies for diabetic patients.

These findings suggest that intermittent PTH and ABL regimens could help restore alveolar bone, improve tooth retention, and enhance dental implant osseointegration in patients with T2D—a population at elevated risk of periodontal bone loss. Because the pro-resorptive effects of these agents were blunted under diabetic conditions, the therapeutic window for net bone gain may be wider in diabetic than in non-diabetic bone. Identifying osteocytic PTH1R as the key anabolic mediator, and marrow cell PTH1R as the driver of resorption, provides a foundation for optimizing PTH pathway-targeted therapies and for developing strategies that maximize bone formation while limiting resorption in diabetic bone disease and other conditions of imbalanced bone remodeling.