Microporous/Macroporous Polycaprolactone Scaffolds for Dental Applications

Effect of Experimental Bleaching Gels With Enzymes on Composite and Enamel

INTRODUCTION AND AIMS

Potential secondary or toxic effects of peroxide-based whitening gels have driven the search for alternative methods that use natural compounds with gentle action on tooth enamel that provide remineralizing benefits.

METHODS

This study introduces four innovative experimental whitening gels (GC, G1, G3, G4) formulated with enzymes (Bromelaine and Papaine) and natural extracts, along with SiO2. The efficacy of these gels was tested on nanohybrid dental composite (EsCOM100, Spident Company) and dental enamel stained with coffee and natural juice (Tedi) over 10 days. The structural changes in samples before and after bleaching were examined using scanning electron microscopy and atomic force microscopy. Additionally, cytotoxicity tests were conducted on the gels using mesenchymal stem cells from human dental pulp (dMSC) and human keratinocytes (HaCaT). Antibacterial activity was assessed on five strains (Streptococcus mutans. Porphyromonas gingivalis; Enterococcus faecalis; Escherichia coli; Staphylococcus aureus).

RESULTS

Coffee and natural juice stains significantly increase the roughness of composite and enamel surfaces by forming deposits. The enzymatic action of bromelain and papain effectively disorganizes and removes these clusters, significantly reducing surface roughness.

CONCLUSION

Notably, the gel containing papain and nanostructured SiO2 proved to be the most effective in removing coffee stains from both composite surfaces and enamel. On the other hand, the gel with bromelain and nanostructured SiO2 was the most efficient in removing natural juice stains. The absence of SiO2 in the experimental gels slightly decreased the enzymes' effectiveness in stain removal. The antibacterial activity observed in the experimental gels is attributed solely to the enzymatic compounds.

Creation of Porous, Perfusable Microtubular Networks for Improved Cell Viability in Volumetric Hydrogels

The creation of large, volumetric tissue-engineered constructs has long been hindered due to the lack of effective vascularization strategies. Recently, 3D printing has emerged as a viable approach to creating vascular structures; however, its application is limited. Here, we present a simple and controllable technique to produce porous, free-standing, perfusable tubular networks from sacrificial templates of polyelectrolyte complex and coatings of salt-containing citrate-based elastomer poly(1,8-octanediol-co-citrate) (POC). As demonstrated, fully perfusable and interconnected POC tubular networks with channel diameters ranging from 100 to 400 μm were created. Incorporating NaCl particulates into the POC coating enabled the formation of micropores (∼19 μm in diameter) in the tubular wall upon particulate leaching to increase the cross-wall fluid transport. Casting and cross-linking gelatin methacrylate (GelMA) suspended with human osteoblasts over the free-standing porous POC tubular networks led to the fabrication of 3D cell-encapsulated constructs. Compared to the constructs without POC tubular networks, those with either solid or porous wall tubular networks exhibited a significant increase in cell viability and proliferation along with healthy cell morphology, particularly those with porous networks. Taken together, the sacrificial template-assisted approach is effective to fabricate tubular networks with controllable channel diameter and patency, which can be easily incorporated into cell-encapsulated hydrogels or used as tissue-engineering scaffolds to improve cell viability.

Biopolymers and Their Application in Bioprinting Processes for Dental Tissue Engineering

Dental tissues are composed of multiple tissues with complex organization, such as dentin, gingiva, periodontal ligament, and alveolar bone. These tissues have different mechanical and biological properties that are essential for their functions. Therefore, dental diseases and injuries pose significant challenges for restorative dentistry, as they require innovative strategies to regenerate damaged or missing dental tissues. Biomimetic bioconstructs that can effectively integrate with native tissues and restore their functionalities are desirable for dental tissue regeneration. However, fabricating such bioconstructs is challenging due to the diversity and complexity of dental tissues. This review provides a comprehensive overview of the recent developments in polymer-based tissue engineering and three-dimensional (3D) printing technologies for dental tissue regeneration. It also discusses the current state-of-the-art, focusing on key techniques, such as polymeric biomaterials and 3D printing with or without cells, used in tissue engineering for dental tissues. Moreover, the final section of this paper identifies the challenges and future directions of this promising research field.