Saeed Hesaraki

Purpose: To compare the clinical and radiographic data after opening wedge high tibial osteotomy (OWHTO) using an allogenous bone graft versus a tricalcium phosphate (TCP) graft. Methods: This prospective clinical study enroled 42 patients (84 knees) between September 2022 and March 2023, undergoing bilateral OWHTO for genu varum. Patients' knees were randomized intraoperatively into two groups: those receiving an allograft or TCP graft to fill the osteotomy defect. Preoperative assessments included pain severity via the visual analogue scale (VAS) and joint function using the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). The osteotomy was corrected using the Minami–Miniaci method, and stabilization was achieved with a fixed‐angle locking plate. Pain, complications and radiographic outcomes were monitored post‐operatively, with bone union assessed via the Hemert criteria. Results: In this cohort of 42 patients (59.5% male, mean age 36.6 ± 5.0 years), all non‐smokers, the mean follow‐up was 2.1 years. Pre‐ and post‐operative comparison using WOMAC (pre‐op = 16.1 ± 8.4; post‐op = allograft: 11.3 ± 4.7, p = 0.00; TCP = 9.3 ± 4.8, p = 0.00) and VAS scores (pre‐op = 2.8 ± 0.9; post‐op = allograft: 2.2 ± 0.8, p = 0.00; TCP = 1.8 ± 1.2, p = 0.00) revealed statistically and clinically significant outcomes. In WOMAC components meaningful pain (pre‐op = 4.4 ± 1.7; post‐op = allograft: 2.9 ± 1.3, p = 0.00; TCP = 2.4 ± 1.4, p = 0.00), stiffness (pre‐op = 1.7 ± 1.2; TCP = 1.3 ± 1.1, p = 0.01) and physical function (pre‐op = 9.9 ± 7.1; post‐op = allograft: 7.7 ± 3.9, p = 0.00; TCP = 6.4 ± 4.0, p = 0.00) improvements at 12 months in both grafts, except stiffness in allograft group (pre‐op = 1.7 ± 1.2 post‐op = allograft: 1.6 ± 1.2, p = 0.08). However, post‐operative analysis revealed that the TCP graft showed statistically significant superiority in WOMAC and VAS scores ( p < 0.05), except pain component of WOMAC (TCP = 2.4 ± 1.4, allograft = 2.9 ± 1.3, p = 0.305). Bone consolidation occurred in 54.8% of cases. No intraoperative complications, infections or loss of correction were reported during follow‐up. Conclusions: Patients undergoing OWHTO with TCP granules experienced better outcomes and less pain, compared to those receiving allogeneic bone grafts. Level of Evidence: N/A.

Background: Calcium phosphate cements (CPCs) are moldable microporous materials widely used for filling bone voids and defects. Introducing macro-porosity into the structure of these cements can enhance the biological functions and the rate of bone formation. Methods: In this study, CPCs with different morphologies (non-porous and porous forms) were used as bone fillers. Different amounts of the porogen were used to obtain different macropore diameters. Bone marrow–derived mesenchymal stem cells (MSCs) were obtained from the tibial shaft of Wistar rats. MSC proliferation was assessed using the MTT assay. Real time PCR and analysis of gene expression for genes relevant to osteogenic differentiation of cells loaded on the samples were carried out. For in vivo evaluations, circular holes were created in the proximal epiphysis of the rabbit tibia bone. The holes were filled with non-porous and macroporous CPCs, and histomorphological evaluation was performed at 4 and 8 weeks after the operation. Results: The results demonstrated that porous CPC was able to increase alkaline phosphatase activity and the expression of bone-related proteins (osteocalcin, osteopontin, and osteonectin) in MSCs cultured on the surfaces of cements. For in vivo evaluations, circular holes were created in the proximal epiphysis of the rabbit tibia bone. The holes were filled with non-porous and macroporous CPCs and histomorphologically evaluated at 4 and 8 weeks after the operation. The results revealed that, Wwhen the hole was filled with non-porous CPC, a layer of connective tissue with immature woven bone was formed at the surface of the implant without any resorption phenomenon. However, when the defect was filled with porous CPC (average pore diameter of 200 µm), the major part of the cement was resorbed and the resorbed cement was replaced by mature bone trabecula and unmineralized osteoid tissue.Conclusion: The creation of macroporous cement could significantly improve the osteogenic ability and the active resorption rate of the cement, further associated with bone replacement by the host tissues.

Condensation silicone dental impression materials are widely used but are limited by polymerization shrinkage, poor wettability, and susceptibility to bacterial contamination. This study evaluates the incorporation of nanosized graphene oxide (GO) as a multifunctional additive to address these issues. GO was incorporated into a self-formulated silicone matrix at concentrations from 0 to 0.5 vol%. The resulting composites were comprehensively characterized for their physical, mechanical, rheological, and antibacterial properties. The incorporation of GO yielded significant, concentration-dependent improvements. Dimensional stability was markedly enhanced, with as little as 0.05% GO reducing 12-hour shrinkage from over 2% to just 0.06%. Handling characteristics were improved, with prolonged working times and enhanced flowability. Mechanical properties were also significantly affected, enabling targeted modification of hardness and flexibility; 0.1% GO increased Shore A hardness by over 14%, while 0.3% GO increased elongation at break by over 55%, demonstrating the ability to optimize the material for either rigidity or flexibility. Surface wettability was improved, with the contact angle decreasing by nearly 19%. Crucially, the composites demonstrated potent antibacterial activity, with 0.2% GO achieving up to 40% efficacy against S. mutans. GO is a highly effective multifunctional additive that simultaneously addresses the key limitations of condensation silicones by enhancing dimensional accuracy, tailoring mechanical properties, improving handling, and increasing hygienic safety. These findings highlight the potential for developing a new class of advanced, high-performance dental impression materials.

Condensation silicones are widely used for dental impressions due to their handling ease and affordability but have limitations like shrinkage, suboptimal rheology, and bacterial contamination risk. This study investigated the effects of incorporating microsized diatomaceous earth (DE) and zinc oxide (ZnO) on the physical, mechanical, rheological, and antibacterial properties of condensation silicone dental impression material. DE/ZnO powders were ball-milled with silica and calcium carbonate, then mixed with hydroxy-terminated polydimethylsiloxane and tetraethyl orthosilicate. The resulting pastes, including a control, were evaluated. Microstructural analysis was conducted via SEM, EDAX, and XRD. SEM/EDAX confirmed filler incorporation: dispersed needle-like ZnO and localized DE aggregates in the silicone matrix. XRD verified ZnO crystalline wurtzite structure and DE cristobalite phase. Incorporating of DE/ZnO extended the setting time and improved the flowability. Compared to the control, ZnO incorporation significantly enhanced dimensional stability, extended working time, slightly decreased hardness, exhibited a lower elastic modulus with significantly higher elongation, and moderately improved wettability. DE incorporation shortened working time, did not improve dimensional stability, slightly decreased hardness, showed similar elastic modulus to the control but with higher elongation, and significantly improved wettability. Antibacterial tests against E. coli and S. mutans revealed significant activity for the ZnO-containing samples but no effects for the DE-containing samples. No significant differences were found in the mixing times among the samples. Results show distinct filler roles: ZnO improves functional properties (stability, antibacterial) and DE modifies surface characteristics (wettability), highlighting potential for targeted property tailoring through filler choice.

Condensation silicones are widely used for dental impressions because of their ease of handling and affordability but exhibit limitations, including shrinkage, suboptimal rheological properties, and potential for bacterial contamination. This study investigated the effects of incorporating microsized diatomaceous earth (DE) and zinc oxide (ZnO) on the properties of a condensed silicone dental impression material, including setting time, rheological behavior, dimensional stability, mechanical properties, wettability, and antibacterial activity. DE and ZnO powders were dry mixed with silica and calcium carbonate via a planetary ball mill. The resulting powder was mixed with PDMS-OH and TEOS. These pastes, along with a control group (silica and calcium carbonate fillers only), were evaluated for mixing, working and setting times and rheological properties. Cured materials were assessed for dimensional stability, tensile strength, hardness, wettability, and antibacterial activity against Escherichia coli and Streptococcus mutans. Microstructural analysis was conducted via SEM, EDAX, and XRD. Incorporating DE and ZnO extended the setting time and improved the flowability. ZnO significantly enhanced the dimensional stability, whereas DE did not. Both fillers slightly decreased the Shore A hardness and increased the hydrophilicity. The ZnO-containing samples had significantly greater antibacterial activity. Both DE and ZnO improved the flowability and enhanced the specific properties of condensed silicone impression materials. ZnO also exhibited significant antibacterial activity. These findings may lead to the development of impression materials with improved handling characteristics, dimensional accuracy, and antibacterial properties.

Beta-tricalcium phosphate (β-TCP) scaffolds manufactured through the foam replication method are widely employed in bone tissue regeneration. The mechanical strength of these scaffolds is a significant challenge, partly due to the rheological properties of the original suspension. Various strategies have been explored to enhance the mechanical properties. In this research, β-TCP scaffolds containing varying concentrations (0.25–1.00 wt%) of multi-walled carbon nanotubes (MWCNT) were developed. The findings indicate that the addition of MWCNTs led to a concentration-dependent improvement in the viscosity of β-TCP suspensions. All the prepared slurries exhibited viscoelastic behavior, with the storage modulus surpassing the loss modulus. The three time interval tests revealed that MWCNT-incorporated β-TCP suspensions exhibited faster structural recovery compared to pure β-TCP slurries. Introducing MWCNT modified compressive strength, and the optimal improvement was obtained using 0.75 wt% MWCNT. The in vitro degradation of β-TCP was also reduced by incorporating MWCNT. While the inclusion of carbon nanotubes had a marginal negative impact on the viability and attachment of MC3T3-E1 cells, the number of viable cells remained above 70% of the control group. Additionally, the results demonstrated that the scaffold increased the expression level of osteocalcin, osteoponthin, and alkaline phosphatase genes of adiposed-derived stem cells; however, higher levels of gene expersion were obtained by using MWCNT. The suitability of MWCNT-modified β-TCP suspensions for the foam replication method can be assessed by evaluating their rheological behavior, aiding in determining the critical additive concentration necessary for a successful coating process.

Background: Tissue engineering is an emerging technology developed for the therapeutic reconstruction of damaged tissue. Objective: In this study, a ceramic/polymer nanocomposite bone tissue engineering scaffold was prepared by coating a tetracalcium phosphate/dicalcium phosphate mixture slurry on a porous 3D chitosan-gelatin construction. Methods: The phase composition, structural groups, and morphological aspects of the samples were characterized. Furthermore, the 3D composite scaffold was immersed in simulated body fluid (SBF) solution at 37ºC for various periods to track its compositional and structural changes. Results: Based on the results, the coated layer is composed of needle-like carbonated apatite nanosized crystals with some tetracalcium phosphate/dicalcium phosphate initial materials. The nanocomposite was porous with an average macropore size of about 410 μm. The in vitro tests revealed that the composition of the coated layer tends to be apatite crystals, which are similar to natural bone in terms of chemistry and morphology. Conclusion: The results suggest that a simple coating of chitosan-gelatin scaffolds using reactive calcium phosphate particles may introduce a novel nanocomposite scaffold with improved mechanical strength, bioactivity, and osteoconductivity.