Search Results (44)

Bacterial colonization and biofilm formation on orthopedic and dental implants remain major clinical complications, while conventional systemic antibiotics are often limited by poor penetration into biofilms and infected bone. These limitations have motivated the development of biomaterials with intrinsic antibacterial activity. Hydroxyapatite (HA), a major inorganic component of bone and teeth, possesses excellent biocompatibility, osteoconductivity, and bone-bonding ability but exhibits limited inherent antibacterial activity. Incorporation of therapeutic metal ions, including Ag⁺, Cu²⁺, Zn²⁺, Ti⁴⁺, Co²⁺, Ga³⁺, Sr²⁺, and Ce³⁺, has therefore emerged as a promising strategy for developing multifunctional HA-based biomaterials. This review critically examines the crystal-chemical basis of metal-ion incorporation into HA and discusses how ionic radius, oxidation state, charge-compensation mechanisms, dopant concentration, and synthesis conditions influence lattice occupancy, physicochemical properties, and biological performance. The antibacterial activity of metal-substituted and metal-modified HA systems generally involves interconnected mechanisms, including bacterial membrane damage, intracellular metabolic disruption, interference with enzymes and nucleic acids, reactive oxygen species (ROS)-mediated oxidative stress, and inhibition of bacterial adhesion and biofilm formation. Ag-, Cu-, Zn-, and Ga-containing HA systems show the most consistently reported antibacterial effects, although their efficacy and cytocompatibility depend strongly on dopant concentration and ion-release kinetics. Co-substituted HA may combine antibacterial activity with angiogenic and osteogenic stimulation, whereas Sr-substituted HA is primarily osteogenic and anti-resorptive, with variable antibacterial performance. Ti-modified HA and TiO₂/HA composites exhibit predominantly photoactive antibacterial behavior, while Ce-substituted HA shows concentration-, oxidation-state-, and synthesis-dependent biological effects. The review also evaluates protein adsorption, osteogenic and angiogenic signaling, macrophage-mediated immunomodulation, biological safety, and representative commercial and translational applications. Overall, metal-substituted HA represents a versatile platform for infection-resistant and regenerative hard-tissue biomaterials, provided that composition, phase structure, ion release, antibacterial efficacy, and cytocompatibility are systematically co-optimized before clinical translation. Full article

Material selection is crucial to hard tissue regeneration, and matching scaffold properties to those of the target tissue can improve clinical outcomes. This study compared the physicochemical, mechanical, and biological performance of fibrous scaffolds fabricated from polycaprolactone (PCL), polydioxanone (PDO), and gelatin methacryloyl (GelMA) for hard tissue regeneration. Polymeric fibers were produced by electrospinning, and their morphological, physical, and mechanical properties were characterized by scanning electron microscopy (SEM, n = 2), swelling and degradation analyses (n = 8), water contact angle measurements (n = 16), and tensile testing (n = 8). In addition, periodontal ligament stem cells (PDLSCs), alveolar bone marrow stem cells (aBMSCs), and dental pulp stem cells (DPSCs) were seeded onto the scaffolds to evaluate cell spreading (n = 4), viability (n = 8), and mineralized matrix formation (n = 6). Data were analyzed using one- or two-way ANOVA followed by appropriate post hoc tests (α = 5%). All polymers formed homogeneous fibrous scaffolds, with diameters within the nanoscale range. PDO and GelMA showed higher swelling than PCL, while PCL retained approximately 95% of its initial mass after three months. PCL and PDO showed higher elongation at break, tensile strength, and Young’s modulus than GelMA. Both PDO and GelMA displayed contact angles below 90°, with GelMA showing the lowest values. In vitro, all polymers were cytocompatible: PDO and GelMA enhanced DPSC viability at 7 days, whereas GelMA produced the highest viability for PDLSCs and aBMSCs at that time point. GelMA also promoted the highest mineralized matrix formation for DPSCs and PDLSCs, with no significant differences among polymers for aBMSCs. Overall, GelMA scaffolds promoted greater cell viability and mineralized matrix formation, while PCL and PDO provided superior mechanical properties, highlighting the importance of balancing biological and mechanical requirements when designing scaffolds for hard tissue regeneration. Full article

Background/Objectives: Methods of smoking have evolved over the years, including heated tobacco products. The impact of exposure to traditional tobacco smoke and heated/electronic tobacco products (IQOS) on biofilm formation has not been previously compared in vitro. Aims and objectives: The present study aimed to evaluate the impact of tobacco and electronic smoking on microbial biofilm formation on dental hard tissues. Materials and Methods: Thirty premolars were randomly assigned to six groups (n = 10 per group) according to tissue type and smoking exposure: Six experimental groups were defined: Group 1, non-exposed enamel; Group 2, enamel subjected to conventional cigarette smoke (CS); Group 3, enamel subjected to heated tobacco (HT); Group 4, non-exposed cementum; Group 5, cementum subjected to conventional cigarette smoke; and Group 6, cementum exposed to heated tobacco. Enamel and root discs were then immersed in 2 mL of an adjusted, standardized bacterial suspension of Streptococcus mutans (S. mutans) to allow bacterial biofilm adhesion after incubation for 48 h at 37 °C. The mean colony-forming unit (CFU) count was calculated, and the surface topography and roughness were assessed using scanning electron microscopy and ImageJ software with the SurfCharJ plugin, respectively. Results: Conventional cigarette smoking showed significantly higher S. mutans adhesion on the enamel and root discs compared with IQOS and control groups. Both IQOS and cigarette smoking increased roughness on enamel and root versus the control group, and cigarette smoking produced significantly higher roughness on the enamel surface when compared to IQOS; however, there were no significant differences in the roughness between the two smoking methods on the root surface. SEM analysis showed the most extensive enamel and root microtopography change in IQOS smoking. Conclusions: Aerosols from heated tobacco products (IQOS) alter the surface topography and roughness of enamel and root, while traditional cigarette smoking significantly increases bacterial colonization. Further in vivo studies are warranted to simulate the dynamic nature of the oral cavity. Full article

Initial carious lesions represent a reversible stage of the caries process in which non-operative strategies can prevent lesion progression and preserve dental hard tissues. This comprehensive review provides an overview of peptide-based approaches for the management of initial carious lesions, with emphasis on self-assembling peptides. The literature was identified through PubMed electronic searches complemented by manual screening of reference lists. Only randomized clinical trials and controlled clinical studies published in English were included. The PICOS framework guided the structure of the review, focusing on patients of any age with initial carious lesions, peptide-based interventions aimed at enamel remineralization, comparisons with placebo, alternative treatments, or standard preventive care (e.g., fluoride products), and outcomes related to de-/remineralisation. Overall, the available evidence suggests that peptide-based strategies can mimic natural biomineralization and promote subsurface hydroxyapatite formation. Among the investigated approaches, the self-assembling peptide P11-4 is the most extensively studied. Evidence supports its safety and its potential to enhance initial carious lesion remineralisation, with possible advantages over fluoride alone in selected cases. In conclusion, peptide-based potentially regenerative approaches, particularly P11-4, represent a promising adjunct in minimally invasive caries management, although further long-term and comparative clinical studies are needed to define their role in routine dental practice. Full article

Most existing dental restorative materials exhibit limited bioactivity, insufficient acid resistance, and poor mechanical compatibility with natural tooth structures. This study involved an in vitro approach in which a biomimetic fluoride-modified functionally gradient dental restorative material was prepared from sol–gel-derived mesoporous silica through mineralization induced via SBF solution. They synthesized bioactive restorative materials by introducing silica into a simulated body fluid (SBF) for biomimetic mineralization and generating hydroxyapatite on the silica surface. XRD, FTIR, SEM, and EDS analyses confirmed the presence of hydroxyapatite and fluorapatite-like phases. The results showed statistically significant improvements (p < 0.05) in the mechanical properties. The surface hardness of the developed restorative system ranged from 214 HV for the prepared silica to 392 HV for the fluoride-modified specimens. Biomimetic mineralization and fluoride modification increased the shear bond strength to dentin substrates from 9.2 MPa to 21.4 MPa and the wear from 12.8 mg to 3.6 mg, respectively. Acid resistance evaluation also showed that the specimens with fluoride modification had the highest value of hardness retention (92.1%) after acid resistance due to the formation of chemically stable and dense apatite-rich layers on the surface. The functionally graded structure demonstrated a partial biomimetic resemblance to certain hierarchical and functional characteristics of natural dental tissues under in vitro conditions. In vitro studies on bioactivity, mechanical properties, and resistance to acidic environments of the synthesized restorative showed promising results for future dental restoration applications. Full article

Recent breakthroughs in materials science have driven transformative advancements in restorative dentistry. Advanced dental materials, such as bioactive materials, nanocomposites, and fibre-reinforced composites, are attracting attention. Bioactive materials, such as calcium silicate-based cements and bioactive glass, represent a paradigm shift by interacting with biological tissues to stimulate regeneration. They promote hydroxyapatite formation, accelerating mineralisation in hard and soft tissues, and are pivotal tools in minimally invasive procedures due to their functions of structural support and biological interaction. Nanomaterials, especially nanocomposites with embedded nanoparticles, effectively address polymerisation shrinkage and wear in traditional composites. With just 1.5% shrinkage, a flexural strength over 150 MPa, and 44–60% higher wear resistance than conventional composites, they offer significant improvements. Nanocomposites also provide enamel-like translucency and a bond strength of 27–38 MPa to dentin, ensuring excellent aesthetics and durability—making them ideal for direct restorations. Fibre-reinforced composites with glass or polymer fibres balance aesthetics with strength and are increasingly used in restorations. Their high fracture resistance, which closely approaches that of a natural tooth, enables clinicians to preserve more healthy teeth during restoration, in line with the principles of modern conservative dentistry. Overall, bioactive materials enhance tissue repair, nanocomposites optimise form and function, and fibre-reinforced composites deliver strength without compromising aesthetics. As these materials transition from research to clinical practice, they promise longer-lasting treatments, fewer complications, and higher patient satisfaction. This narrative review aims to explore three types of advanced dental materials and their role in improving clinical outcomes. Full article

Hydraulic calcium silicate cements (HCSCs) are contemporary materials in vital pulp therapy (VPT) and regenerative endodontic therapy (RET) due to their favorable effects on pulpal and periodontal cells, including cell differentiation and hard tissue formation. Recent studies also indicated the involvement of several S100A proteins in inflammatory, differentiation, and mineralization processes of the pulp. The aim of the present study was to investigate the effects of HCSCs on S100A gene expression in human dental pulp stem cells (hDPSCs). Human DPSCs were isolated and characterized by multi-lineage stem-cell markers and differentiation protocols. In stimulation experiments hDPSCs were exposed to ProRoot^®MTA, Biodentine^®, IL-1β, and dexamethasone. Cell viability was determined by XTT assay. IL-6 and IL-8 mRNA expression was measured to analyze proinflammatory response. In addition, odontogenic differentiation and biomineralization assays were conducted (DSPP- and ALP-mRNA expression, ALP activity, and Alizarin Red staining). Differential expression of 13 S100A genes was examined using qPCR. Low concentrations of HCSCs enhanced the proliferation of hDPSCs, whereas higher concentrations exhibited cytotoxic effects. HCSCs induced a pro-inflammatory response and led to odontogenic differentiation and biomineralization. This was accompanied by significant alterations in the expression levels of various S100A genes. ProRoot^®MTA and Biodentine^® significantly affect the expression of several S100A genes in hDPSCs, supporting their role in inflammation, differentiation, and mineralization. These findings indicate a link between the effects of HCSCs on human pulp cells during VPT or RET and S100A proteins. Full article

Dental composites are commonly used for the restoration of hard tooth tissues, but their low fracture toughness may limit their lifespan. In this study, the effect of liquid rubber modification on the mechanical properties and fracture mechanisms of two types of dental composites, flow and classic, was evaluated. The study used experimental composites containing a mixture of dimethacrylate resins: BisGMA (20% by weight), BisEMA (30% by weight), UDMA (30% by weight), and TEGDMA (20% by weight). Composites were reinforced with Al-Ba-B-Si glass, Ba-Al-B-F-Si glass with particle sizes of 0.7 and 2 μm respectively, as well as pyrogenic silica (20 nm). The inorganic phase was introduced in an amount of 50% vol. for flow material and 80% vol. for classic composite. As a modifier, Hypro 2000X168LC VTB liquid rubber (Huntsman International LLC, USA) was used in an amount of 5% by weight relative to the matrix. The flexural strength, Young’s modulus, and fracture toughness were evaluated. Numerical FEM analysis allowed for the evaluation of stress distribution in the filling area. The results confirmed that the modification of composites with liquid rubber contributes to an increase in fracture toughness. For the flow-type material, the fracture toughness increased from 1.04 to 1.13 MPa·m^1/2. At the same time, a decrease in flexural strength from 71.90 MPa to 61.48 MPa and in Young’s modulus from 2.98 GPa to 2.53 GPa. In the case of the classical composite, the modification with liquid rubber also improved the resistance to fracture, increasing it from 1.97 to 2.18 MPa·m^1/2 while the flexural strength decreased from 102.30 MPa to 90.96 MPa, and the modulus dropped from 7.33 GPa to 6.16 GPa. FEA analysis confirmed that modified composites exhibit a more favorable stress distribution with lower tensile stress levels (approximately 20 MPa in contrast to 25 MPa for the classic composite). Mechanisms of fracture and strengthening were also identified. The main fracture mechanism was intermolecular cracking with crack deflections. Modification with liquid rubber resulted in the formation of elastic bridges and plastic shear zones at the front of the crack. Full article

Bone graft materials frequently employed in dental implant placement procedures, including hydroxyapatite and β-tricalcium phosphate (β-TCP), are typically granular in form, which complicates their manipulation and contributes to extended treatment durations. A tissue engineering approach utilizing readily manageable biomaterials in conjunction with mesenchymal stem cells (MSCs) represents the most promising approach in dentistry. This study assessed the bone-augmenting capacity at bone defect sites in inbred rats by seeding dedifferentiated fat (DFAT) cells onto a cotton-like bone graft scaffold composed of β-TCP and poly(L-lactic-co- glycolide) (PLGA), which was subsequently wrapped around titanium. As a control, cotton-like bone graft material without cells was used and wrapped around and transplanted. Four weeks post-implantation, computed tomography (CT) images of the DFAT group revealed a 1.25-fold enhancement in hard tissue formation compared to the control group. Histological analysis revealed compact structure in a dark red color surrounding the cotton-like bone graft material was observed on the titanium surface of DFAT group. Histomorphometric analysis revealed that the amount of hard tissue generated in the DFAT group was approximately 2.5 times higher than that observed in the control group. Moreover, this mineralized tissue demonstrated properties analogous to those observed in cortical bone. Collectively, these findings indicate that the composite of DFAT cells and cotton-like bone graft material holds potential for bone augmentation applications and represents a promising approach for regenerative therapies within the orofacial region. Full article

Minimizing the risk of secondary caries in dentistry is achieved by using adhesive systems that provide a strong bond between the natural hard tissue and the restorative material. Evaluating the effectiveness of these systems requires studying both their interaction with dentin and enamel and their behavior in environments with varying acidity. In this work, the interaction of a reactive monomer, 4-methacryloxyethyl trimellitic anhydride (4-META), used in adhesive systems with both dentin-like hydroxyapatite (HA) and hydroxyapatite ceramics, was investigated. Kinetic studies showed that under experimental conditions, 4-META was hydrolyzed and amorphized. Dentin-like HA possessed greater adsorption capacity to 4-META than ceramic HA. Immersion of HA into a solution of 4-META led to formation of an acidic calcium phosphate phase over time in both systems. Studies on the solubility of the synthetic nanosized hydroxyapatite and its derivative with 4-META in 0.1 mol/L lactic acid, also containing CaCl₂, Na₂HPO₄, and NaF (pH 4.5), and in distilled water (pH 6.3) indicated the occurrence of dissolution, complexation, and crystallization processes, causing changes in the liquid and solid phases. The total Ca²⁺ concentration upon dissolution of hybrid HA-4-META in a lactic acid solution was three times lower than the total Ca²⁺ concentration upon dissolution of pure HA. This suggested that 4-META-treated dentin-like surfaces demonstrate greater resistance to dissolution in acidic environments compared to untreated surfaces, highlighting the potential for these hybrids in dental applications. Full article

Due to the bio-inert nature of titanium (Ti) and subsequent accompanying chronic inflammatory response, an implant’s stability and function can be significantly affected, which is why various surface modifications have been employed, including the deposition of titanium oxide (TiO₂) nanotubes (TNTs) onto the native surface through the anodic oxidation method. While the influence of nanotube diameter on cell behaviour and osteogenesis is very well documented, information regarding the effects of nanotube lateral spacing on the in vivo new bone formation process is insufficient and hard to find. Considering this, the present study’s aim was to evaluate the mechanical properties and the osteogenic ability of two types of TNTs-based pins with different lateral spacing, e.g., 25 nm (TNTs) and 92 nm (spTNTs). The mechanical properties of the TNT-coated implants were characterised from a morphological point of view (tube diameter, spacing, and tube length) using scanning electron microscopy (SEM). In addition, the chemical composition of the implants was evaluated using X-ray photoelectron spectroscopy, while surface roughness and topography were characterised using atomic force microscopy (AFM). Finally, the implants’ hardness and elastic modulus were investigated using nanoindentation measurements. The in vivo new bone formation was histologically evaluated (haematoxylin and eosin—HE staining) at 6 and 30 days post-implantation in a rat model. Mechanical characterisation revealed that the two morphologies presented a similar chemical composition and mechanical strength, but, in terms of surface roughness, the spTNTs exhibited a higher average roughness. The microscopic examination at 1 month post-implantation revealed that spTNTs pins (57.21 ± 34.93) were capable of promoting early new bone tissue formation to a greater extent than the TNTs-coated implants (24.37 ± 6.5), with a difference in the average thickness of the newly formed bone tissue of ~32.84 µm, thus highlighting the importance of this parameter when designing future dental/orthopaedic implants. Full article

Background: Optical coherence tomography (OCT) is an emerging, radiation-free diagnostic tool in dentistry, providing high-resolution, real-time imaging of both hard and soft tissues, including periodontal areas, for more accurate postoperative evaluations. This study aims to investigate the efficacy of OCT on periodontal tissues in animals by comparing the healing effects of laser therapy with those of conventional surgical instruments. Methods: Six rabbits underwent periodontal surgery using a laser, scalpel, and punch to perform an apically positioned flap on the mandibular anterior incisors and to create a tongue ulcer on the dorsal surface of the tongue. Visual and OCT evaluations were conducted on days 1, 2, 3, 7, and 14. Results: In periodontal surgery, the laser exhibited slightly faster healing compared to other methods. In tongue ulcer formation, the scalpel and punch groups demonstrated slightly faster healing than that of the laser. However, both methods ultimately showed similar healing outcomes. Conclusions: In the dental field, OCT is emerging as a valuable tool for assessing healing, including early stages of healing, in periodontal therapy. Full article

Synthetic oligodeoxynucleotides (ODNs) containing unmethylated cytosine–phosphate–guanine (CpG) motifs (CpG-ODNs) are ligand molecules for Toll-like receptor 9 (TLR9), which is expressed by odontoblasts in vitro and dental pulp cells. This study determined the effects of CpG-ODNs on pulpal immunomodulatory response and repair following injury. Briefly, the upper right first molars of three-week-old mice were extracted, immersed in Type A (D35) or B (K3) CpG-ODN solutions (0.1 or 0.8 mM) for 30 min, and then replanted. Pulpal healing and immunomodulatory activity were assessed by hematoxylin–eosin and AZAN staining, as well as immunohistochemistry. One week following the operation, inflammatory reactions occurred in all of the experimental groups; however, re-revascularization and newly formed hard tissue deposition were observed in the pulp chamber of all groups at week 2. A positive trend in the expression of immune cell markers was observed toward the CpG-ODN groups at 0.1 mM. Our data suggest that synthetic CpG-ODN solutions at low concentrations may evoke a long-lasting macrophage–TLR9-mediated pro-inflammatory, rather than anti-inflammatory, response in the dental pulp to modulate the repair process and hard tissue formation. Further studies are needed to determine the effects of current immunomodulatory agents in vitro and in vivo and develop treatment strategies for dental tissue regeneration. Full article

Nano-hydroxyapatite (nHA) demonstrates favorable biological activity, cell adhesion, cell proliferation, and osteoconductivity, making it highly valuable in biomedicine. It is extensively used as a bone substitute and in bone transplantation within the dental and orthopedic fields. This study employed oyster shells as a calcium source to synthesize nHA at 150 °C with various hydrothermal reaction durations (10 min, 1 h, 6 h, and 12 h). As a control, HA synthesized via a wet precipitation method for 1 h at room temperature was utilized. Subsequent material analyses, including XRD, FE-SEM, FTIR, and ICP-MS, were conducted, followed by comprehensive evaluations of the bioactivity, cell attachment, cell proliferation, and sintering properties of the synthesized nHA. The results indicated that nHA synthesized through the hydrothermal reaction produced nanoscale crystals, with the aspect ratio of nHA particles increasing with the duration of hydrothermal treatment. Notably, rod-like nHA particles became prominent with hydrothermal durations exceeding 6 h. nHA particles derived from oyster shells contained carbonate and trace elements (Na, Mg, K, and Sr), similar to constituents found in human hard tissue such as bone and teeth. The immersion of nHA synthesized at 150 °C for 1 h (HT2) in simulated body fluid (SBF) for 28 d led to the formation of a bone-like apatite layer on the surface, indicating the excellent bioactivity of the synthesized nHA. The cell culture results revealed superior cell attachment and proliferation for nHA (HT2). Following the sequential formation and sintering at 1200 °C for 4 h, HT2 ceramics exhibited enhanced microhardness (5.65 GPa) and fracture toughness (1.23 MPa·m^0.5), surpassing those of human tooth enamel. Full article

Dental erosion represents the gradual and irreversible depletion of dental hard tissues due to a chemical process, independent of bacterial influence. It has emerged as a notable clinical concern in recent years, primarily attributed to substantial lifestyle shifts resulting in the heightened intake and frequency of acid-containing foods and beverages. Apart from the extrinsic erosive agents derived from external sources, such as dietary habits or medication, intrinsic erosive agents may exist due to pathological reasons with the contents of the stomach including gastric juice, mainly composed of hydrochloric acid, being their sole source. Currently, bioactive materials are used in various forms for the prevention of dental erosion. Such materials include, among others, bioactive glasses (BAGs). BAGs are a type of glass that, when in contact with biological fluids, can elicit a specific biological response. When they come into contact with bodily fluids, they can initiate a series of processes, including the formation of a hydroxyapatite layer on the glass surface. This bioactivity is particularly advantageous in medical and dental applications, where BAGs are used for bone regeneration, tissue repair, and dental restorative or preventive techniques. The aim of this literature review was to analyze and discuss the role of BAGs in protecting the tooth structures from dental erosion. The analysis of the existing literature regarding this topic indicated that the use of BAGs in preventive treatments against tooth erosion can be useful in dental practice. Further clinical evidence is necessary to confirm the effectiveness of the particular preventive measures. Full article