The goal of the third generation of biomaterials, which includes bioactive glasses (BGs), is to improve tissue regeneration and repair. By interacting with the biological environment, these materials promote tissue regeneration. When BGs come into contact with physiological fluids, they readily connect with the host bone tissue, simulating hard tissue. The natural equilibrium of bone remodeling may be upset, and therapeutic ion release may be impacted by the breakdown of silicon-based glasses over time. Borosilicate bioactive glasses (BBG) are a solution to this problem since they improve the quality of bioactive glass disintegration.

Using a modified Stober sol–gel approach, we synthesized a range of BBGs in this study by substituting boron into the base BG at varying ratios. To describe the BBGs' physicochemical and in vitro acellular bioactivity characteristics, several methods were used, including Thermogravimetric analysis, inductively coupled plasma atomic emission spectroscopy, Fourier-Transform Infrared Spectroscopy, X-ray diffraction, Brunauer–Emmet–Teller and Barrett–Joyner–Halenda theories, nuclear magnetic resonance, and Scanning Electron Microscopy attached with energy-dispersive X-ray spectroscopy. Additionally, the rate of BG breakdown in a simulated bodily fluid over a range of durations up to 21 days was measured using a Seven Compact pH/Ion S220 pH meter.

Based on our research, the BGs' pH values upsurged and their dissolution ability was increased when the boron concentration was raised. The boron-induced structural modifications appear to have improved the kinetics of dissolution, allowing for faster ion release into the surrounding fluid. These results provide prospects for the controlled release of therapeutic ions in BBG systems. Furthermore, the rate of hydroxyapatite precipitation was slower in the BGs with higher boron concentrations. This is connected to how the BGs' decreased pore volume and specific surface area impacted the bioactivity of the glass. This finding advances knowledge of the apatite formation and dissolution behavior of BBG.

Zirconia is in well known as a dental biomaterial and has been applied as structural material for implants, dental bridges, crowns or inserts due to its biocompatibility, high fracture toughness, and radiopacity. On the other hand oxide ceramics can undergo subcritical cracking which is crucial parameter in the case of a long-term loading in a humid environment (such as human body). Pure zirconium oxide stabilized with yttrium oxide is considered also as an inert material. To improve bioactive properties, modifying additives are used to induce a specific biological response. One of the most common bioactive filler, which enhances early and late bone-to-implant integration; is represented by hydroxyapatite. Another example of a material that has the effect of enhancing osteointegration is bioglass. Bioactivity can also be understood in the context of providing dental materials with antibacterial function. Among the most commonly used antibacterial materials are silver and copper nanoparticles. In the present work we tried to consider 3 aspects simultaneously. First of all determination of slow crack growth parameters and then lifetime estimation of biocomposites made of ZrO₂ and hydroxyapatite (HAp), where zirconia powder was obtained by hydrothermal method. Secondly, comparison of biological properties such as antibacterial efficacy and biocompatibility of ZrO₂/HAp in respect of ZrO₂ composites modified with hexagonal boron nitride (hBN), bioglass (BG), and bioglass containing copper (BGCu). Thirdly, demonstration of bioactive properties that promote the formation of an apatite layer on the biocomposite surface in contact with SBF.

Our findings indicated that all materials demonstrated a high degree of biocompatibility. However, it is noteworthy that a slight cytotoxicity was observed in the composites modified with HAp and hBN. Furthermore, the same composite materials exhibited notable antibacterial properties against Gram-positive bacteria and some Gram-negative strains. Moreover, the mechanical tests showed that ZrO₂/HAp biocomposites revealed susceptibility to subritical cracking.

Introduction

Intraoral bone regeneration requires the use of meshes made of titanium alloy (Ti6Al4V) placed under the oral mucosa as space maintainers and with adequate stiffness to withstand chewing loads. However, excessive load resistance could damage the mucosa with the exposure of meshes and infectious problems. Also, polycaprolactone (PCL), a resorbable polymer, is used as a mesh because it has high hardness at physiological temperatures. Both Ti6Al4V and PCL need to be sterilized before use. The objectives of this study are to compare the response to mechanical load between sterile PCL (SPCL), virgin PCL (VPCL) and Ti6Al4V meshes.

Methods

Fifteen meshes with dimensions of 10 mm x 30 mm were designed with free CAD software; thickness was 0.2 mm for five Ti6Al4V meshes and 0.8 mm for ten PCL meshes. The meshes were produced with selective laser melting for Ti6Al4V and a fused deposition modeling for PCL. Before loading, five PCL meshes were sterilized in a laminar flow hood using ethanol solution (70%) for 30 minutes, washed in distilled water for 10 minutes and then left to air-dry. All meshes were fixed at four points at the ends and loaded centrally with a universal testing machine (MTS 810) running at 130N and a 10 mm/min speed using a spherical point measuring 10 mm in diameter until the first failure.

Results

The first failure of VPCL and SPCL appeared at 46 ± 1.74 N and 36 ± 3,83 N, respectively, while it appeared at 83,1 ± 19,97 N for Ti6Al4V. PCL showed low stiffness compared with Ti6Al4V (2,8 ± 0,67, 2,0 ± 0,19 and 9,4 ± 2,11 N/mm for VPCL, SPCL, and Ti6Al4V, respectively).

Conclusions

Ti6Al4V displays higher stiffness compared with PCL, but the latter is more than adequate for withstanding physiological chewing loads and as a space maintainer. Furthermore, the PCL stiffness values ​​are similar to those of keratinized mucosa reported in the literature.

Introduction: Dental caries remains the most common dental problem. Due to the high cost of treatment, there is a growing interest in the use of more preventive and minimally invasive biotechnological methods. Hydroxyapatite (HA), due to its excellent biocompatibility, finds wide application in dentistry as a remineralizing component. The use of enzymes is promising for the destruction of cariesogenic bacterial biofilms. The low resistance of bacteria to the action of enzymes is a great advantage of this approach. Thus, this work is devoted to the development of new composite dental materials of prolonged action based on hydroxyapatite, enzyme-destructors and biodegradable polymers for caries treatment.

Methods: The compositions were prepared by mixing gelatin, HA and enzymes (glucoamylase, glucose oxidase, lysozyme) in aqueous solution in a given ratio. The suspensions were poured into molds, frozen and subjected to lyophilic drying. Structural and morphological characteristics of the obtained biomaterials in the form of plates were analyzed using SEM with EDS analysis system. The absorbance and degradation kinetics of the plates were measured in PBS medium at 37 °C. Antibacterial properties were studied against microorganisms found in the oral cavity.

Results: In the course of the study, new biomaterials in the form of plates were obtained, which can be active against pathogenic microflora of the oral cavity and have a mineralizing effect in the processes of restoration of damaged enamel. The plates have a slightly hydrophobic surface and their dissolution in PBS starts only after 30 min, which are positive factors for prolonged action in the composition of active components. The addition of enzymes accelerates the dissolution of the plates.

Conclusions: Based on the results, the obtained biomaterials are suitable for the treatment and prevention of dental caries, indicating the potential for their further in vivo study.

Carbon allotropes, including graphene, graphene oxide (GO), and reduced graphene oxide (r-GO), have potential as coating nanomaterials to improve the performance of dental implants.

Furthermore, graphene has demonstrated strong antibacterial activity and enhanced biocompatibility in comparison to other types of carbon nanoscale structures.

Several bibliometric studies have been published on the use of graphene-based materials, but they only focus on scientific articles and not patents.

A few articles report on a patent study of dental implants but without focusing on carbon allotropes.

The objective of this study is to provide the patent landscape analysis of graphene and its derivatives in relation to dental implants.

The search for relevant information was conducted on Espacenet (https://worldwide.espacenet.com, provided by the EPO—European Patent Office), using keywords and classification codes, specifically, the IPC (International Patent Classification) and CPC (Cooperative Patent Classification).

Dental implants are primarily classified in the A61C13/00 and A61C8/00 subgroups, while the classification symbol for graphene and its derivatives, such as graphene oxide, is C01B32/182 and its lower subgroups.

By combining the abovemention symbols with keywords, a total of 68 patents/patent applications were obtained.

After reading the title, abstract, and claims, 16 documents were excluded as they were off-topic and not related to the use of graphene or its derivatives in dental implants.

The Orbit Intelligence platform (https://www.orbit.com) was used to analyze the 52 relevant results obtained. Of these, 55.8% are granted patents, 26.9% are pending patent applications, 5.8% were revoked, and 11.5% lapsed.

The first patent application was filed in 2010.

China has the highest number of applications with 20, followed by the USA with 7 and South Korea with 6.

Graphene oxide is the most commonly claimed carbon allotrope, while titanium and its alloys are among the most frequently used materials.

Introduction: conventional nanohybrid (CeramX) and ormocer-based (Admira fusion) dental composite resins were compared investigating their effects on human dental pulp stem cells (hDPSCs) in terms of cytotoxicity, migration and osteogenic differentiation.

Methods: The samples and the eluates were prepared according to ISO 10993-12. hDPSCs were treated with different dilutions (undiluted, from 1:2 to 1:100) of CeramX and Admira fusion eluates. Viability assays were conducted in standard or osteogenic conditions using the MTT test. Furthermore, we analysed the migration activity with scratch test. Osteogenic differentiation potential was evaluated exclusively at dilution of 1:50 by Alkaline Phosphatase Activity and Alizarin Red Staining assay.

Results: Admira Fusion demonstrated to be highly biocompatible and positively influenced the proliferation of hDPSCs; on the contrary, CeramX showed to be more cytotoxic. The ormocer-based eluate exhibited osteo-inductive effects on hDPSCs when diluted at ratio of 1:50; conversely, conventional nanohybrid composite did not show any notable effect on stem cells differentiation.

Conclusions: The lower cytotoxicity observed with Admira Fusion compared to the conventional nanohybrid composite could be attributed to a reduced monomers release in the oral environment. This evidence supports the hypothesis of limited adverse effect and enhanced healing potential, particularly when the material is positioned in close contact with pulp tissue.

Introduction: Polymer 3D printing has gained wide applications in the medical field. Polyamide 12 has been used to reconstruct bony defects. Coating its surface with calcium phosphate compounds, as hydroxyapatite, could enhance its bonding with bone. In this study, a simple innovative surface treatment was introduced by applying light-cured cement to coat 3D-printed polyamide 12 specimens with hydroxyapatite.

Methods: Polyamide 12 powder was printed by selective laser sintering to produce 40 disc-shaped specimens (15 mm diameter x 1.5 mm thickness). The specimens were divided randomly into two main groups: 1) a control (untreated) group, where the surface of the specimens was left without any modifications; and 2) a treated group, where the surface of the specimens was coated with hydroxyapatite by a new method using a light-cured dental cement. Each group was further subdivided into two subgroups according to the immersion in simulated body fluid (SBF). The first subgroup was not immersed in SBF and was left as printed, while the second subgroup was immersed in SBF for 15 days (n = 10/subgroup). The surfaces of the control and treated specimens were examined using an environmental scanning electron microscope (SEM) and energy-dispersive X-ray analysis (EDXA) before and after immersion in SBF.

Results: The SEM micrographs of the control 3D-printed polyamide 12 specimens illustrated the agglomerated 3D-printed particles with minimal porosity. Their EDXA revealed the presence of carbon, nitrogen, and oxygen. This surface was not affected by immersion in SBF, as detected by SEM and EDXA. The microstructure of the coated specimens showed deposited clusters of calcium and phosphorus on the surface, in addition to carbon, nitrogen, and oxygen. This coat was stable after immersion, as detected by SEM and EDXA.

Conclusions: Using light-cured cement could be considered a simple method to coat the 3D-printed polyamide 12 with hydroxyapatite.

Background: In restorative dentistry, zinc oxide eugenol (ZOE) cements are among the most commonly used temporary materials. Eugenol has several therapeutic benefits, including sedative, anti-inflammatory, bacteriostatic, and pain-relieving properties. It is also advantageous because of its low cost and ease of application and removal. Researchers are trying to strengthen ZOE because, despite its benefits over other temporary fillers, including varnish, zinc polycarboxylate, and calcium hydroxide, it has a lower mechanical strength. Recently, E-glass fibers have shown great promise as reinforcing fibers because of their excellent mechanical behavior, sufficient bonding, and acceptable aesthetics. Objectives: To assess ZOE cements and those reinforced with manual incorporation of 10% E-glass fibers in terms of compressive strength, surface microhardness, and solubility. Methods: The control group was prepared by mixing dental ZOE powders with their liquid. The innovatively reinforced dental ZOE group was prepared by incorporating 10 wt.% E-glass fibers into the ZOE powder prior to liquid mixing. Particle size distribution (PSD), scanning electron microscopy (SEM), and X-ray fluorescence (XRF) were used to characterize the E-glass fibers. Evaluations of the modified group were conducted on its compressive strength, surface microhardness, and solubility. Independent-sample t-tests were used to statistically analyze the data and compare mean values (p < 0.05). Results: The findings demonstrated that, in comparison to the unmodified ZOE, the modified ZOE had a significantly lower mean value of solubility and a significantly higher mean value of compressive strength and surface microhardness (P≤0.05). Conclusion: The modified ZOE cements with 10 wt.% E-glass fibers provide enhanced compressive strength, surface microhardness, and reduced solubility, which encourages their use as permanent dental restorative materials.

The use of medical implants is becoming more widespread, which is attracting great interest in the development of new technologies for their production. Titanium-based implants are the most common now, but the polymer polyetheretherketone (PEEK) is studied as a substitute. Despite the biotolerance to titanium and PEEK, their implantation in the human body is often accompanied by some negative effects. This problem is solved by depositing biocompatible coatings on the implant's surface, in particular, calcium phosphates (CPs). CP coatings on implants are produced by different techniques, each of which has its own disadvantages related to both the quality of the formed coatings and their cost.

Biocompatible coatings based on hydroxyapatite (HAP) on metal and polymer implants were obtained by gas-detonation deposition (GDD). This method consists ofthe acceleration of HAP powder by a detonation wave resulting from the explosion of a mixture of acetylene and oxygen. HAP powder particles are introduced into the detonation wave and accelerate to high speeds and form a coating on the implants. Among the main advantages of GDD are its high productivity, the ability to form layers of different thickness on large-area substrates in a few minutes, the possibility of varying the coating composition, the high adhesion with low energy consumption of the process and, accordingly, the low cost.

HAP coatings with a thickness ~ 200 microns on titanium and PEEK substrates were studied by Raman spectroscopy, XRD and microscopic analysis. This study showed the formation of a porous coating on the titanium substrate, which consisted of crystalline and partially amorphous HAP. The latter was transformed into a crystalline one during annealing at 600 ^oC. The HAP coating on PEEK was shown to consist of HAP with a small admixture of tricalcium phosphate. The appearance of the latter is explained by the partial transformation of HAP microparticles into tricalcium phosphate when they collide with the surface.

The successful osseointegration of an implant depends on numerous factors, both material-related (phase composition, mechanical properties, implant morphology, presence of doping agents) and recipient-related (health status, nature of inflammation, material's influence on immunostimulation and reparative histogenesis). Modeling each stage of regeneration separately and combining stages gradually to form a comprehensive model appears to be an appropriate approach for identifying relationships between these factors.

This study aims to assess the contribution of the resorption rate of the osteoplastic material to the process of bone defect regeneration. Dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP), and hydroxyapatite (HA), obtained by the hydrolysis of precursors, were used. Resorption kinetics were evaluated using isotonic buffer solutions SBF and PBS in stationary and dynamic closed systems (up to 28 days; t=37°C; without solution replacement). In the stationary system, a phase transformation of DCPD to OCP was observed for both solutions, which was quantitatively described by a theoretical model based on first principles of chemical kinetics. An equilibrium between the material and saturated solution was observed for OCP and HA samples.

For experiments in the dynamic system, a bioreactor was developed to mimic physiological fluid flow. Under these conditions, no phase transformation of DCPD to OCP occurred in either solution, and an equilibrium between the material and saturated solution was observed. This was explained within the previously obtained theoretical model, taking into account Fick's second law.

Similar experiments were conducted using a mixture of culture medium DMEM and bovine blood serum. It was found that serum albumin adsorbs as a monolayer on the surface of calcium phosphates (Langmuir-type I isotherm), significantly inhibiting the dissolution rate of DCPD and the crystallization rate of OCP.

All obtained data were described within a unified theoretical model, further development of which is the focus of future research.