Hypertension and estrogen deficiency can affect bone metabolism and therefore increase the risk of osseointegration. Antihypertensive drugs such as losartan not only control blood pressure but also enhance bone healing. In addition, alendronate sodium is widely used to treat postmenopausal osteoporosis. Hence, we evaluated the effect of systemic antihypertensive and local alendronate coted on implants on osseointegration under hypertensive and estrogen-deficiency conditions. A total of 64 spontaneously hypertensive rats (SHRs) treated with losartan were randomly divided according to the estrogen-deficiency induction by ovariectomy (OVX) or not (SHAM), and whether the implant surface was coated with sodium alendronate (ALE) or not, resulting in four groups: SHR SHAM, SHR SHAM ALE, SHR OVX, and SHR OVX ALE. The removal torque, microcomputed tomography, and epifluorescence microscopy were the adopted analyses. The hypertensive and estrogen-deficiency animals presented a lower removal torque even when treated with alendronate on implant surface. The microcomputed tomography revealed a higher bone volume and bone-to-implant contact in the SHRs than the SHR OVX rats. Epifluorescence showed a decreased mineral apposition ratio in the SHR OVX ALE group. The data presented indicate that estrogen deficiency impairs osseointegration in hypertensive rats; in addition, alendronate coated on the implant surface does not fully reverse this impaired condition caused by estrogen deficiency.

Hypertension is a global health concern not only correlated with cardiovascular complications, but also with impaired bone metabolism, potentially affecting healing at the bone–implant interface. Losartan, an angiotensin II receptor blocker (ARB) commonly prescribed for hypertension, has shown beneficial effects on bone healing in spontaneously hypertensive rats (SHRs). However, the influence of hypertension and ARBs like losartan on the bone cellular response at the bone–implant interface remains underexplored. Methods: A total of 32 rats were included in this study: 16 SHRs, with 8 receiving losartan (30 mg/kg daily) and 8 receiving no treatment, and 16 normotensive Wistar rats, with 8 receiving losartan and 8 receiving no treatment. After one week of treatment, titanium implants were placed into the tibia of all the animals. The bone–implant interface was assessed 60 days post-implantation using micro-computed tomography (µCT) and an immunohistochemical analysis. Results: (i) The ARB treatment significantly increased the bone volume and bone–implant contact in the SHRs receiving losartan compared to the untreated SHRs. (ii) Consistent with the µCT findings, the immunohistochemistry further confirmed regular bone turnover and increased osteocalcin (OC) mineralization in the treated SHRs. In contrast, no alterations in the bone microarchitecture were noted in the Wistar rats treated with losartan. Conclusions: The results suggest that losartan, an ARB drug, improves bone volume and bone turnover at the bone–implant interface in SHRs.

Synthetic bone substitutes based on hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) are widely used in regenerative dentistry due to their favorable biocompatibility and osteoconductive properties. This study aimed to evaluate, through laboratory-based analyses, the porosity and surface characteristics of the Nanosynt Block (FGM Dental Group®) for bone regeneration applications. The Nanosynt Block, consisting of 60% HA and 40% β-TCP, was analyzed using scanning electron microscopy (SEM) for surface morphology characterization, micro-computed tomography (Micro-CT) for internal structure evaluation, and mercury intrusion porosimetry for porosity assessment. SEM imaging followed the ASTM E1829-02 standard, while Micro-CT and porosimetry provided detailed quantitative data. SEM analysis revealed a homogeneous pore distribution on the surface. Micro-CT indicated high structural stability and consistent volumetric porosity, ranging from 73.27% to 77.08%. Porosimetry indicated a total porosity of 94.9%, with a median pore diameter of 799 nm, characteristics suitable for promoting cellular adhesion and fluid infiltration. The structural and morphological properties of the Nanosynt Block highlight its potential to support initial bone formation and mechanical stability in clinical applications. These findings provide a robust basis for subsequent in vivo investigations to validate its clinical efficacy.

Hypertensive individuals present alterations in their calcium metabolism that consequently decrease the concentration of this mineral in the bone tissue.