Background <p>Abaloparatide is a second-generation osteoporosis drug that prevents bone loss and stimulates bone fromation. This study evaluated the effects of abaloparatide treatment on alveolar bone loss (ABL) in osteoporotic rats with periodontitis by immunohistochemical and microcomputed tomography (micro-CT) in rats with periodontitis and osteoporosis.</p> Methods <p>Forty adult female rats were divided into five equal groups: non-ligated (controls), periodontitis (P), periodontitis + osteoporosis (PO), PO treatment with 10&#xa0;µg/kg abaloparatide (PO-10), and PO treatment with 80&#xa0;µg/kg abaloparatide (PO-80). Bilateral ovariectomy was conducted in the osteoporosis groups. Three weeks after ovariectomy, experimental periodontitis was induced via Ligature. Abaloparatide was performed at the same time as the induction of experimental periodontitis. All rats were sacrificed at 30 days. ABL was determined via micro-CT and histological analyses. Bone morphogenetic protein 2 (BMP-2), alkaline phosphatase (ALP), receptor ligand for nuclear factor-kappa B (RANKL), osteocalcin (OCN), osteoprotegerin (OPG), and collagen 1 (Col-1) were evaluated immunohistochemically. In addition, the levels of C-terminal telopeptide of type I collagen (CTX), which is related to bone turnover, were analyzed.</p> Results <p>Periodontitis with osteoporosis significantly increased ABL in the PO versus the P group. Abaloparatide treatment significantly reduced ABL in the treatment groups and significantly increased BMP-2, ALP, Col-1, OPG, OCN, and CTX levels. In particular, 80&#xa0;µg/kg abaloparatide treatment significantly modulated the RANKL, OPG, and CTX levels in the PO-80 group. The micro-CT results indicated that abaloparatide treatment significantly enhanced the percentage of bone, trabecular thickness, trabecular number, and bone surface density.</p> Conclusion <p>Abaloparatide treatment regulates bone formation dose-dependently by decreasing ABL in rats with periodontitis and osteoporosis.</p>