Bone tissue engineering has emerged as a promising approach to addressing the limitations of traditional bone grafts for repairing bone defects. This regenerative medicine strategy leverages biomaterials, growth factors, and cells to create a favorable environment for bone regeneration, mimicking the body’s natural healing process. Among the various biomaterials explored, hydrogels (HGs), a class of three-dimensional, hydrophilic polymer networks, have gained significant attention as scaffolds for bone tissue engineering. Thus, this review aimed to investigate the potential of natural and synthetic HGs, and the molecules used for its functionalization, for enhanced bone tissue engineering applications. HGs offer several advantages such as scaffolds, including biocompatibility, biodegradability, tunable mechanical properties, and the ability to encapsulate and deliver bioactive molecules. These properties make them ideal candidates for supporting cell attachment, proliferation, and differentiation, ultimately guiding the formation of new bone tissue. The design and optimization of HG-based scaffolds involve adapting their composition, structure, and mechanical properties to meet the specific requirements of bone regeneration. Current research focuses on incorporating bioactive molecules, such as growth factors and cytokines, into HG scaffolds to further enhance their osteoinductive and osteoconductive properties. Additionally, strategies to improve the mechanical strength and degradation kinetics of HGs are being explored to ensure long-term stability and support for new bone formation. The development of advanced HG-based scaffolds holds great potential for revolutionizing bone tissue engineering and providing effective treatment options for patients with bone defects.

This review explores the emerging role of functionalized hydrogels in modulating the microbiome for therapeutic applications in tissue regeneration and infection control. The skin and gut microbiomes play crucial roles in maintaining tissue homeostasis, regulating immune responses, and influencing the healing process. Disruptions in microbial balance—such as those observed in chronic wounds, autoimmune conditions, or post-surgical environments—can impair regeneration and increase susceptibility to infection. Hydrogels, due to their tunable physical and chemical properties, serve as versatile platforms for delivering probiotics, prebiotics, antimicrobials, and immune-modulatory agents. The encapsulation of beneficial bacteria, such as Lactobacillus plantarum or Prevotella histicola, within hydrogels could enhance bacterial viability, targeted delivery, and immune tolerance. Additionally, hydrogels functionalized with silver nanoparticles, nitric oxide donors, and bacteriocins have demonstrated effective biofilm disruption and pathogen clearance. These systems also promote favorable immune responses, such as M2 macrophage polarization and the induction of regulatory T cells, which are essential for tissue repair. Innovative approaches, including 3D bioprinting, self-healing materials, and photothermal-responsive hydrogels, expand the clinical versatility of these systems.

Objective: This study aimed to analyse dysbiotic changes of periodontal pathogenic bacteria and their relationship with different types of fixed orthodontic appliances in a population located in Northwestern Mexico. Methods: Three groups of patients were identified: a control group without orthodontic appliances (C), a conventional-ligating appliance group (CLA), and a self-ligating appliance group (SLA). Periodontal biofilm samples were collected for DNA extraction to identify the presence and load of Treponema denticola, Prevotella intermedia , and Fusobacterium nucleatum , using a quantitative real-time PCR technique. Results: A total of 92 patients were included. The results showed that F. nucleatum was present in all groups including the control patients (C 96%, CLA 100%, and SLA 67%, respectively). Female participants displayed a higher frequency of periodontal pathogens than males, but males were more affected by F. nucleatum . In addition, the presence of T. denticola and P. intermedia was time-dependent, being more frequent in patients in treatment for longer than 12 months whereas CLA showed 74% and 78% of positive samples and SLA showed 78% and 89%, respectively. F. nucleatum was present in 100% of CLA samples before and after 12 months of treatment and its load was higher in the SLA group after 12 months. Conclusions: Dysbiotic changes that could affect the periodontal tissues were seen in patients wearing orthodontic appliances. The frequency of F. nucleatum was significantly higher in CLA and noted with a greater load in SLA. In addition, female participants showed a higher frequency of periodontal pathogens while male subjects were more affected by F. nucleatum . As expected, treatment for longer than 12 months correlated with a higher frequency of all periodontal pathogens. The results support the concept that dysbiosis leading to periodontal disease can be caused by the rise of a dominant species, instead of the appearance of a new species.