Jithendra Ratnayake

The journal retracts the article “Effect of Currently Available Nanoparticle Synthesis Routes on Their Biocompatibility with Fibroblast Cell Lines”

The tooth is a complex biological organ composed of multiple tissues, including enamel, dentine, cementum and pulp. However, dental disease and tooth loss due to periodontitis, caries, or trauma adversely affect most adults at some time in their lives. Tooth regeneration represents a shift in the dental paradigm from removal to repair to regeneration. Tooth regeneration is an extension of the broader field of regenerative medicine, aiming to restore a tissue defect to its original form and function by using biological substitutes to replace lost teeth or tooth tissue, providing a viable alternative to currently available clinical treatments. A full array of cell sources has been trialled for endodontic regeneration, following the basic premise of tissue engineering, including cells–scaffold–bioactive molecules. Several reports have documented dental pulp-like tissue regeneration, either in vitro or following the transplantation of stem cells. Tooth regeneration follows two unique approaches: cell transplantation and cell homing. Cell transplantation has been the predominant approach, whereas cell homing aims to achieve tissue repair and regeneration of the injury site through the chemotaxis of host endogenous cells. This narrative review explores therapeutically viable tooth regeneration approaches by contrasting cell transplantation and cell-to-scaffold methodologies focussing on the cell–scaffold–bioactive molecule triad.

A bone graft is defined as a material capable of promoting bone healing, which has been transplanted into a bony defect, either alone or in combination with other materials.[1] The earliest documented bone graft dates to 1682, when a cranial bone was repaired using bone from a deceased dog. In 2024, the global bone grafts and substitutes market was valued at USD 3.16 billion and is projected to reach USD 4.60 billion by 2030, with a growth rate of 6.6%.[2] After tooth loss, alveolar bone resorption is irreversible, leaving the area without adequate bone volume for future successful implant treatment. Despite the widespread use of bone grafting materials globally, limitations in these materials remain, highlighting the need for continued innovation. Autografts are the gold standard in bone grafting materials. These are sourced from intraoral and extraoral sites in the same individual, such as the mandibular symphysis, mandibular ramus, external oblique ridge, iliac crest, proximal ulna or distal radius, as these are good sources of cortical and cancellous bone.[3] [4] For dental applications, autografts are commonly used for the management of localized alveolar bony defects, maxillary sinus bone grafting, and alveolar ridge augmentation procedures. However, autografts are limited by graft tissue availability, associated donor-site pain and morbidity, higher surgical costs, greater surgical risks, and the need for two operative sites and procedures.[5] [6] Consequently, allografts from a compatible living donor or cadaveric bone are a more acceptable alternative to autografts. Allograft materials are available in three primary forms: fresh, frozen, or freeze-dried. Fresh and frozen allograft materials possess superior osteoinductive properties; for example, demineralized bone matrix (DBM), which contains osteoinductive growth factors, is available in different forms, such as putties, moldable pastes, and moldable blocks, with clinically relevant handling properties.[3] In dental applications, allografts have been used to treat periodontal, maxillary, and mandibular defects. However, allografts are subject to potential risks such as rejection and disease transmission, and require thorough sterilization to eliminate disease potential.[3] In recent years, there has been a shift toward novel bone grafting materials, such as xenografts and synthetic bone substitute products, despite limited evidence-based research on their indications and safety. The primary role of bone grafts is to provide a scaffold that stimulates new bone growth and to display biological properties such as osseointegration, osteogenesis, osteoconduction, and osteoinduction, which play a vital role in this process.[3] Furthermore, material properties such as biocompatibility, resorbability, sterility, structural integrity, adequate porosity for angiogenesis, ease of handling, cost, and compressive strength influence the success rate of bone grafts.[7] To address some of these limitations, novel bone substitutes have been developed to enhance osteogenic, osteoconductive, and osteoinductive properties by creating a more favorable bone microenvironment.[3] Xenografts are graft materials derived from a species that is genetically unrelated to the host.[8] The most common source of xenograft material in the dental field is defatted, deproteinized bovine bone, which is commercially available as BioOss, and contains the mineral hydroxyapatite (HA).[3] HA is present as the inorganic component of bone and teeth, and therefore provides an ideal bone grafting material.[4] Notably, synthetically produced HA lacks the trace amounts of Na⁺, Mg²⁺, K⁺, and Sr2⁺, which are found in naturally derived HA, such as in bovine bone, and these ions facilitate various biochemical reactions that enhance osteogenesis. Furthermore, synthetic HA does not possess the microporous structure observed in natural bovine-derived HA.[4] The porous structure of BioOss provides good mechanical support and stimulates bone regeneration via angiogenesis, cell migration, and differentiation. Studies have found that maxillary sinus defect sites grafted with BioOss resulted in 39% new bone formation after 6 months, which was comparable to 40% new bone formation following autograft bone grafting at the same time point. Furthermore, it was found that 31% of grafted BioOss remained at the graft site, compared with just 18% of autograft bone,[9] suggesting that the efficacy of BioOss in stimulating new bone formation closely matches, if not exceeds, that of autograft bone. A 5-year prospective follow-up study conducted by Özkan et al found that sufficient bone quality and volume, allowing for predictable simultaneous implant placement, resulted from the use of bovine bone grafts in one-stage maxillary sinus augmentation procedures.[10] Clinically, BioOss has proven to be a valuable grafting material, consistently providing high-quality new bone and exhibiting promising long-term survival rates in dental surgery.[11] OsteoGraf and Cerabone are other commercially available bovine bone grafts produced by high-temperature treatment, which eliminates all organic components. Recent studies conducted by Ratnayake et al have developed bone graft material from bovine bone and teeth using a sustainable, green, and cost-effective method.[6] [8] In vitro studies showed that the bone graft materials were non-toxic and supported the proliferation and differentiation of osteoblast-like cells. In addition to bovine sources, other xenogeneic sources have also been explored. For example, bone and teeth sourced from Saudi Arabian camels are currently being investigated for the development of bone grafts, with in vitro biocompatibility studies showing promising results.[12] [13] Nevertheless, future studies should focus on in vivo studies and clinical trials to assess the clinical feasibility of these emerging xenograft materials. Other promising xenograft materials include chitosan, which is a naturally occurring polymer composed of glucosamine and N-acetylglucosamine, derived from crustacean exoskeletons.[7] [14] Chitosan has been widely investigated as a xenograft material due to its antimicrobial and biocompatible properties. It is available in a variety of forms, including beads, films, hydrogels, and more complex structures, such as porous scaffolds.[14] Due to chitosan's poor mechanical strength, it is often combined with other materials, such as calcium phosphates (HA), gelatin, and bioglass, to impart more desirable mechanical properties.[14] Furthermore, chitosan-based grafting materials also possess other beneficial properties, such as low immunogenicity, fibrous encapsulation, structural versatility, and a hydrophilic surface that promotes cell adhesion and proliferation.[14] Recent studies in the dental field have reported the successful application of chitosan-based materials as membranes for guided bone and tissue regeneration, as coating agents for implant surfaces, for periodontal regeneration, and for the restoring alveolar bone height. Silk is a natural biopolymer derived from the silkworm Bombyx mori and is predominantly composed of fibroin and sericin. After removal of sericin through degumming, silk fibroin (SF) is commonly used as a bone scaffold in sponge, film, and hydrogel forms. SF demonstrates excellent biocompatibility, degradability, tissue integration, oxygen and water permeability. Recent research has shown that these favorable biological properties enable its use as a membrane for guided bone regeneration (GBR), despite its poor mechanical properties and difficulties in use.[15] [16] SF has been used as a GBR membrane following tooth extraction, cyst/tumor excision, and in cases of deficient alveolar bone for implant placement. Furthermore, SF-based membranes have exhibited excellent tensile strength, good osteogenic potential, and good mechanical properties in several in vivo studies.[16] [17] Phytogenic materials are bone-analogue grafting materials derived from plant sources, such as Gusuibu, coral-based bone substitutes, and marine algae. Gusuibu is a traditional Chinese herbal medicine widely used to treat patients with bone fractures and osteoarthritis in Chinese patients and has shown osteoinductive properties, increased alkaline phosphatase activity, and thus promotes bone calcification and remodeling processes.[18] In dental applications, gusuibu has been shown to accelerate bone remodeling following orthodontic tooth movement by promoting osteoblastic activity, and in vitro, it has been shown to mediate bone remodeling by regulating osteoclastic and osteoblastic activity.[19] AlgiPore is a naturally occurring HA derived from marine algae that has been clinically used as a bone grafting material since 1988. AlgiPore is a very favorable grafting material for bone filling due to its excellent biocompatibility, low immunogenicity, biodegradability, and bone-bonding capacity. Clinically, Algipore is primarily used as a space filler, often in combination with other grafting materials, following tooth extraction to prevent ridge deformities.[20] Despite the establishment of criteria defining the ideal bone grafting material, autografts remain the gold standard and the only material that possesses all four fundamental biological properties. However, their limited availability and other associated limitations have driven a shift toward the development of alternative grafting materials. Synthetic options can be expensive and lack the full spectrum of biological properties necessary for bone grafting, and clinicians must consider the limitations of these new technologies. Therefore, there is a growing need to investigate these innovative biomaterials derived from natural, sustainable sources, capable of producing novel dental bone grafts with the necessary porous structure, mechanical stability, controlled degradation, and a rate of new bone formation that matches the rate of graft resorption. Presently, 3D (three-dimensional) bioprinting is widely explored, involving the printing of biomaterials that integrate biological materials, such as cells and growth factors, to mimic the structure of targeted tissues while maintaining cell viability during and after printing.[21] These developments are being performed in a hydrogel or a 3D scaffold to develop new therapies for bone regeneration.[21] Such strategies could allow natural biomaterials to more closely imitate the multifaceted biological microenvironment of natural bone, representing a key area of future research. Article published online: 22 May 2026 © 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/) Thieme Medical and Scientific Publishers Private Limited A-13A, Graphix Tower 1, 6th floor, Sector 62, Noida 201309, Uttar Pradesh, India

Aim: Hydraulic calcium silicate cements are widely employed in endodontics due to their excellent biocompatibility, bioactivity, sealing ability, and remineralisation potential. However, currently used products such as mineral trioxide aggregate (MTA) exhibit several limitations, including discolouration, cost, and poor handling properties. Therefore, this study aimed to develop and characterise a bovine‐derived hydroxyapatite (BHA) and montmorillonite (MMT) nanoclay hybrid composite (BHA‐MMT), incorporating zirconium oxide as a radiopacifier and calcium silicate phases as setting agents. Methodology: BHA was produced from waste bovine bones using a defatting and deproteination method. MMT clay was exfoliated into nanoclay using shear force with a planetary ball mill. The composite powders were prepared by combining BHA (20% and 25% wt), zirconium oxide (30% wt), setting agents with exfoliated MMT (15% and 20% wt) to produce three composite materials with different BHA and MMT ratios, namely B20, B25, and M20. The resulting powders were mixed with deionised water to form hydraulic cements. The composite materials were tested for chemical, mechanical, and physical properties compared with the commercially available ProRoot MTA. The biocompatibility, bioactivity, and remineralisation potential of the materials were also examined using established in vitro assays . Results: The pH of the material increased above 11 after 24 h and remained constant up to 21 days. The compressive strengths of B20, B25, and M20 were 23.63, 21.2, and 23.8 MPa, respectively, after 21 days. The mean setting time of the composites ranged from 13 to 14 min, and the concentrations of heavy metals were within the permissible limits specified by ISO standards. The experimental composite materials demonstrated radiopacity values within the range, consistent with ISO recommendations. Among the variants, B20 and B25 demonstrated good cell viability, while M20, containing a higher proportion of MMT, showed enhanced apatite formation and remineralization, indicating improved bioactivity. Conclusion: The developed BHA–MMT composites demonstrated promising physicochemical, biological, and remineralisation properties consistent with ISO standard requirements. Overall, the product represents a bioactive composite material system; further investigations, including in vivo studies, are necessary to confirm its clinical applicability in vital pulp treatment (direct/indirect pulp capping, pulpotomy) and root‐end filling procedures.

Background: Dental caries demineralises the enamel and dentine of the teeth, and as infection progresses it can lead to pulpal inflammation, infection and severe pain. Aim: To determine and compare the level of mRNA expression of Toll‐like receptors (( TLR )‐2, TLR‐4 and TLR‐9 ), tumour necrosis factor ( TNF )‐α, interleukins (( IL )‐1α, IL‐1β , IL‐4, IL‐6, IL‐8, IL‐17 and IL‐23 ) as well as markers of dentinogenic (dentine matrix protein ( DMP )‐1, dentine sialophosphoprotein ( DSPP )), regulatory (nuclear factor‐kappa B ( NF‐κB1 ), mitogen activated protein kinase (MAPK1)), proliferative (mitogen activated protein kinase ( MKi )) and stemness (sex determining region Y‐box 2 ( SOX2 )) between non‐carious and carious dental pulp tissues. Methodology: This study undertook a comprehensive analysis of inflammatory markers including TLR ‐2, TLR‐4 , TLR‐9 , TNF ‐α, IL ‐1α, IL‐1β , IL‐4, IL‐6, IL‐8, IL‐17 and IL‐23 , as well as markers of dentinogenic DMP ‐1, DSPP , NF‐κB1 , MAPK1 , proliferative MKi and stemness SOX2 processes in healthy and carious pulp tissues using quantitative real‐time reverse‐transcription polymerase chain reaction. Results: We found higher levels of TLR‐2, TLR‐4, IL‐6, IL‐8, IL‐17A, IL‐23A , along with NF‐κB1 and MKi67 in the carious pulps ( p < 0.05). The concurrent upregulation of IL‐17A and IL‐23A may suggest the activation of the IL‐23/IL‐17 signalling axis in the carious pulps, a point underreported in the literature. Conclusion: These findings highlight the crucial role of the immune system in pulpal inflammation and potential implications in developing targeted molecular treatments, supporting the need for further translational research.

In the quest for highly esthetic and strong restorative material, dental technicians, practitioners, and manufacturers have produced several compositions of ceramic materials. Increasing the strength of ceramics without compromising their translucency remains a major challenge. Like porcelain-fused-to-metal crowns, veneering the strong and opaque ceramic cores with a translucent porcelain may improve the strength of porcelain crowns. However, frequent chipping of this weak veneering layer was a major problem. Recently, the advent of computer-aided design/computer-aided manufacturing (CAD/CAM) has allowed the production of stronger ceramics while minimally increasing their translucency and eliminating the need for the veneering layer. Therefore, the current review aims to provide an overview and a critique of the evolution and development of all-ceramic restorations, while also focusing on the material properties and considerations related to their use in restorative dentistry.

Wound healing is a physiological process including haemostasis, inflammation, proliferation, and remodelling. Acute wounds typically follow a predictable healing process, whereas chronic wounds cause prolonged inflammation and infection, failing to progress through typical healing phases and presenting significant clinical challenges. A combination of wound care techniques and therapeutic agents is required to manage chronic wounds effectively. Curcumin is a bioactive compound derived from Curcuma longa and has gained attention for its potent antioxidant, anti-inflammatory, and antibacterial properties. The first part of this review aims to provide a comprehensive overview of the physiology of wound healing, focusing on the pathophysiology and management of acute and chronic wounds, followed by the biological activity of curcumin in wound healing, emphasising its impact on promoting tissue repair. Finally, this review explores curcumin-loaded dressings, such as hydrogels, nanofibrous membranes, polymeric micelles, and films, offering controlled drug release and targeted curcumin delivery to enhance wound healing.

Bioceramic materials for endodontic treatments have gradually transformed over the years into materials with enhanced biocompatibility and chemical and mechanical properties compared to earlier generations. In endodontics procedures, these materials are used as restorative material in applications such as root-end fillings, pulp capping, perforations repair, and apexification repair procedures. However, they have far from ideal mechanical and handling properties, biocompatibility issues, aesthetic concerns due to tooth discolouration, limited antibacterial activity, and affordability, which are amongst several key limitations. Notably, bioceramic materials are popular due to their biocompatibility, sealing ability, and durability, consequently surpassing traditional materials such as gutta-percha and zinc oxide–eugenol sealers. A lack of recent advancements in the field, combined with nanomaterials, has improved the formulations of these materials to overcome these limitations. The existing literature emphasises the benefits of bioceramics while underreporting their poor mechanical properties, handling difficulties, cost, and various other drawbacks. The key gaps identified in the literature are the insufficient coverage of emerging materials, narrow scope, limited insights into future developments, and underreporting of failures and complications of the existing materials. Consequently, this review aims to highlight the key limitations of various endodontic materials, primarily focusing on calcium silicate, calcium phosphate, and bioactive glass-based materials, which are the most abundantly used materials in dentistry. Based on the literature, bioceramic materials in endodontics have significantly improved over recent years, with different combinations of materials and technology compared to earlier generations while preserving many of their original properties, with some having affordable costs. This review also identified key innovations that could shape the future of endodontic materials, highlighting the ongoing evolution and advancements in endodontic treatments.

Hydroxyapatite, renowned for its biocompatibility and osteoconductive properties, plays a fundamental role in bone regeneration owing to its resemblance to natural bone mineral, thus offering considerable potential for advancing tissue engineering strategies. In this article, the innovative integration of silicon ions into biogenic (bovine-derived) hydroxyapatite (SiBHA) via a tailored sol-gel process is reported. The resultant SiBHA scaffolds exhibited an interconnected microporous structure with a total porosity of 70% and pore dimensions ranging from 120 to 650 µm. Fourier-transform infrared spectroscopy and X-ray diffraction studies validated the effective incorporation of silicon ions into the BHA lattice, with energy-dispersive X-ray and inductively-coupled plasma mass spectrometry further confirming a Ca/P molar ratio for SiBHA between 1.63 and 1.74. Moreover, SiBHA scaffolds demonstrated commendable chemical and thermal stability. Of note, SiBHA scaffolds were found to display significantly enhanced mechanical properties, including compressive strength and Young’s modulus, compared to the control BHA scaffolds. In vitro assessments highlighted the capacity of SiBHA scaffolds to foster cell viability, proliferation, and osteogenic differentiation of Saos-2 cells. Immunohistochemical analysis revealed a significant increase in osteonectin expression, a key bone matrix protein, after 14 days of incubation under osteogenic conditions. These findings highlight the biocompatibility and therapeutic potential of SiBHA scaffolds, suggesting their suitability as biomaterials for dental bone regeneration applications.