Simvastatin embedded into poly(lactic-co-glycolic acid) (PLGA)-based scaffolds can stimulate bone regeneration in preclinical models. However, the ideal pharmacological dose has not been evaluated. This systematic review reports on the simvastatin doses used in preclinical studies and evaluates the regeneration of critical-sized bone defects. References were selected in a two-phase process. Electronic databases (Embase, LILACS, LIVIVO, PubMed, SCOPUS, and Web of Science) and grey literature databases (Google Scholar, Open Grey, and ProQuest) were searched until September 2022. The risk of bias was considered to be low based on the SYRCLE tool. We identified four studies in rat, two in parietal and two in calvaria bone, one in mouse parietal bone, and one in rabbit femur bone. Simvastatin, ranging from 8 to 100 µg, significantly increased bone formation in five studies, as compared to the scaffold alone based on µ-computed tomography, histomorphometric, and radiography analysis. The median increase in bone formation caused by simvastatin was 2.1-fold compared to the PLGA-based scaffold alone. There was, however, no significant correlation between the relative bone gain and the doses of simvastatin (p = 0.37). The data suggest that relatively lower doses of simvastatin can consistently promote preclinical bone regeneration. However, the interpretation of these data must consider the heterogenicity of the PLGA-scaffolds, the defect anatomy, the observation period, and the evaluation method.

The objective of this review was to critically evaluate the available literature on the development of periodontal ligament organoids. Articles concerning periodontal ligament organoids were considered eligible. References were selected in a two-phased process. Electronic databases PubMed and Scopus were screened up to June 2024, yielding 1101 studies. After removing duplicates, titles, and abstracts were screened, resulting in 44 articles being included in this review. A detailed analysis of the included articles was organized into four categories: (1) the cell lineages used, including the simultaneous use of two or more cell types, (2) the extracellular matrix composition, (3) the organoid preparation methods, and (4) the characterization techniques employed. The main findings show that collagen combined with biodegradable polymers—such as poly(caprolactone), poly(glycolic acid), and poly(lactic acid)—is the most used material. Periodontal ligament cells and periodontal fibroblasts were the most used cell types, due to their role in extracellular matrix remodeling. The most frequent analyses performed included alkaline phosphatase, extracellular matrix mineralization, and gene expression, providing insights into differentiation and periodontal regeneration. Cementogenic differentiation was the most studied, followed by osteogenic, chondrogenic, adipogenic, and epithelial differentiation. However, challenges remain, including methodological inconsistencies and the need for scaffold optimization. Future research should focus on standardizing protocols, improving biomaterials, and integrating bioprinting techniques to improve clinical translation.

Periodontal organoid research remains underdeveloped, largely due to the lack of standardized fabrication protocols and multicellular constructs capable of reproducing epithelial–mesenchymal interactions relevant to periodontal biology. In particular, it remains unclear whether different spatial assembly strategies influence construct stability, multicellular organization, or early molecular behavior in periodontal three-dimensional (3D) systems. Therefore, this study aimed to develop and compare two different methods for generating dual-lineage 3D periodontal organoid-like constructs using human periodontal ligament cells (hPDL) and human gingival epithelial cells (hGEP). These strategies were selected to compare two biologically and technically distinct spatial configurations: bilayer assembly to partially mimic epithelial–connective tissue compartmentalization, and surface seeding as a simplified fabrication approach with potential advantages for reproducibility and workflow standardization. Both cell types were cultured in different media conditions (CnT-57, DMEM, and a 1:1 CnT-57/DMEM mixture) to determine compatibility for co-culture applications. Cell viability was assessed on days 1, 3, and 7 using the MTS assay. Constructs were produced in hyaluronic acid-based hydrogels using two strategies: Group 1–sequential photopolymerization of hPDL and hGEP layers to generate a bilayer construct; and Group 2—encapsulation of hPDL followed by direct seeding of hGEP onto the construct surface. Viability within constructs was evaluated on days 3 and 7 using the Live/Dead assay. Morphology was monitored using stereomicroscopy on days 0, 1, 3, and 7. Exploratory RNA sequencing was performed on day 7 to characterize transcriptomic profiles. All tested culture media maintained cellular viabilities above 70%, with no statistically significant differences among conditions (p > 0.05), indicating biocompatibility for both cell types. Group 1 exhibited viabilities of 86.54% ± 8.55% and 90.69% ± 7.88% on days 3 and 7, respectively, while Group 2 showed viabilities of 87.00% ± 9.58% and 88.08% ± 9.12%, with no significant intergroup differences (p > 0.05). Morphological analyses demonstrated preservation of construct integrity and progressive interaction between epithelial and mesenchymal compartments. Exploratory RNA sequencing revealed only subtle transcriptomic differences between assembly strategies. In conclusion, both methodologies successfully generated viable and structurally stable dual-lineage periodontal organoid-like constructs within a hyaluronic acid-based matrix. Comparison of these two assembly strategies demonstrates the feasibility of generating reproducible multicellular periodontal 3D models using distinct spatial configurations, establishing a proof-of-concept platform for future optimization toward periodontal disease modeling, regenerative studies, and advanced biofabrication applications.