Hard Tissue Research Articles

Effect of the Synergistic Interaction of Micro- and Nanostructures with Silver Ions on the Biocompatibility and Antimicrobial Properties of Ti-15Mo-2.5Ag.

Titanium and titanium alloys have the advantages of a low density and a close elastic modulus to natural bone, which can reduce the stress-shielding effect and become one of the first choices for human hard tissue replacement and repair. However, implant site infection is still one of the main reasons for implantation failure. In this paper, 2.5 wt % Ag element was added to Ti-15Mo to obtain a low modulus, and a surface anodization was applied to improve the surface biocompatibility. The elastic modulus, micromorphology, surface elemental valence, corrosion resistance, antimicrobial properties, and cytocompatibility were investigated by mechanical tests, scanning electron microscopy, X-ray photoelectron spectroscopy, electrochemical tests, inductively coupled plasma spectroscopy, plate counting method, and cellular tests. The experimental results showed that the anodized Ti-15Mo-2.5Ag sample exhibited an elastic modulus of 79 GPa, a strong corrosion resistance, a strong antimicrobial ability of ≥99.99%, and good biocompatibility. It was demonstrated that the formation of Ag2O on the surface and Ag ion release improved the antimicrobial properties and that the structural synergism of silver ions with micro- and nanostructures played an important role in promoting the early spreading of cells and improving the cytocompatibility.

Competence of allogenic demineralized tooth matrix in socket seal surgery for alveolar ridge preservation: a randomized control clinical trial.

To assess and compare the clinical, radiological, and histological outcomes of socket seal surgery between two protocols: deproteinized demineralized tooth matrix (dpDTM) and freeze-dried bone allograft (FDBA) each covered with a free gingival graft. Twenty extraction sockets in the anterior or premolar region were randomly allocated to either the dpDTM or FDBA protocol (n = 10 per group). Measurements of the alveolar ridge changes were obtained using an intraoral scanner and cone-beam computed tomography at 3 months post-operation. Three-month post surgery, the dental implant was installed (n = 5 per group), bone biopsies were obtained for histomorphometrical and micro-computed tomography analyses. Implant stability quotients (ISQs) were determined and compared at 3 months post-implant. Lower significant reductions in buccal alveolar ridge height and hard tissue volume were observed in dpDTM group compared to FDBA group at 3 months (0.25 ± 0.35mm vs. 1.60 ± 0.66mm [p = .000] and 9.64 ± 15.39% mm3 vs. 31.45 ± 18.11% mm3 [p = .010], respectively). At the same time, lower soft tissue volume reduction was detected in the dpDTM group compared to FDBA group (4.21 ± 5.25% mm3 vs. 5.25 ± 5.79% mm3). No statistically significant difference in the percentage of mineralized tissue formation was found between dpDTM group (53.39 ± 11.16%) and FDBA group (49.90 ± 3.27%). Even though the ISQ in the dpDTM group showed a higher value than the FDBA group at 3 months post-implant, the results were without statistical significance. Alveolar ridge preservation using dpDTM is an efficacious procedure for providing the conditions for the development of functional and esthetic implants.

Recent advances in antimicrobial and biosynthesis properties of bioglass and nanoparticles: A narrative review

Oral hard and soft tissue engineering using bioactive substances that trigger other proteins or the immune system is the main focus of biomaterials research. Long-lasting tissues and tissue components develop due to this natural ground ingredient. Bioactive glass (BAG) is one type of biomaterial that is currently used. BAG is utilized in soft-tissue restoration, orthopedics, air abrasion, pulp capping, root canal therapy, dental implant coating materials, mineralizing agents and dental restorative materials, among other medical specialities, due to its bioactive properties, which make it suitable for use in a range of clinical settings, including dentistry and medicine, where issues with complex tissue regeneration arise.Bioglass is used in dentistry for permanent restoration, intracanal medication or temporary restorative purposes. This article extensively explores the applications of Bioglass in dentistry, explicitly focusing on elucidating its mechanisms of action and biological effects. Emphasizing the uniqueness of Bioglass, this article underscores its role as a transformative tool in modern dental care.

The effects of beverage erosion on enamel: evaluating surface characteristics and loss of calcium and phosphate ions

BackgroundThe erosive impacts of various beverages on dental enamel have been identified as a potential erosive threat to dental hard tissues. This in vitro study aimed to address this by utilizing a systematic approach and advanced analytical methods to study enamel erosion due to selected beverages in a simulated oral environment.MethodsForty-nine extracted sound second premolar teeth were collected, disinfected, and prepared. These teeth were randomly allocated into seven groups, each exposed to a different beverage: distilled water, mineral water, instant coffee, black tea, Pepsi-Cola, orange juice, and synthetic vinegar. The modified Nordini Artificial Model (mNAM) was used to simulate the oral cavity. The enamel surfaces were scanned using a Scanning Electron Microscope (SEM) and analyzed using Energy-Dispersive X-ray Spectroscopy (EDS). Surface hardness was measured using the Knoop Hardness Scale. Statistical analysis was conducted using the Wilcoxon signed-rank test, with a significance level set at p < 0.05.ResultsDistilled water and mineral water exhibited no significant changes in enamel surface or hardness. Coffee caused an 8–9% loss of calcium and phosphate, indicating potential erosion. Black tea showed signs of remineralization rather than demineralization. Pepsi-Cola and orange juice caused substantial erosion, with Pepsi-Cola resulting in a nearly 24% loss of calcium. Vinegar had a marked erosive effect, with a 17% loss of both calcium and phosphate. SEM images corroborated these findings, showing pronounced enamel prisms and increased visibility of minor cracks in post-treatment teeth. EDS analysis revealed significant changes in the elemental composition of the enamel.ConclusionsThis study categorised beverages based on their pH and fluoride content, revealing that drinks like Pepsi-Cola and orange juice are acidic but low in fluoride, whereas black tea, mineral water, and vinegar are acidic yet contain fluoride. The study suggests that the decrease in pH of acidic beverages may contribute to dental erosion, with fluoride as a mitigating factor. Among the various metrics assessed for evaluating dental erosion, hardness emerged as the most reliable quantitative parameter.

Assessment of dental hard tissues and periodontium in children with hemophilia

Relevance. Children suffering from hemophilia primarily receive dental care when they present with acute tooth pain or exacerbation of an existing condition. Due to the rarity (orphan nature) of hereditary coagulopathies, dentists often lack the experience and knowledge to utilize modern methods of prevention and treatment for this patient category. Additionally, the lack of regular dental check-ups for children with hemophilia often leads to a high level of oral morbidity and a need for specific treatments, as indicated by literature data.Materials and methods. The primary methods used to assess oral health in children with hemophilia included detailed questioning, detection of carious lesions in dental hard tissues, assessment of oral hygiene, and the condition of periodontal tissues.Results. Among pediatric patients with hemophilia, poor oral hygiene was associated with a high prevalence of carious lesions (100%) and very high caries intensity values (8.8, ranging from 7 to 11). Additionally, there was a relatively high prevalence of gingival inflammation, accompanied by pronounced gingival bleeding. A direct correlation was identified between the level of oral hygiene and the degree of gingival bleeding in children aged 6-17 years with hemophilia. The deterioration of dental indicators corresponded to the severity of hemophilia, the primary disease in these children.Conclusion. The study demonstrated that pediatric patients with hemophilia, particularly those with moderate to severe forms, had significantly worse indicators of oral hygiene, dental hard tissues, and gingival health compared to generally healthy children. The results indicate the necessity for dental monitoring and rehabilitation for children with hemophilia to detect and effectively treat oral diseases at early stages.

Dental anomalies in congenital error of immunity

Developmental disorders of the teeth and maxillofacial region are part of a symptoms complex that often occur with inborn errors of the immune system. The purpose of the study is to identify the frequency of various dentofacial anomalies occurrence in patients with diagnosed immunodeficiencies. The study involved 64 patients of the Sverdlovsk Regional Clinical Hospital No. 1 and the Regional Children’s Clinical Hospital (Ekaterinburg) with various diagnoses: combined immunodeficiencies, antibody defects, autoinflammatory disorders, defects in the number and functions of phagocytes, defects in immune dysregulation, complement defects, and unverified diagnosis with signs of immunodeficiency. All patients underwent examination of the oral cavity, hard dental tissues, periodontal tissue and jaw bone tissue. It was found that an anomaly in jaw size is characteristic of all studied patient groups, except for the group with complement defects. Along with this, such pathology as quantitative and qualitative changes in teeth was identified in four classification groups: “combined immunodeficiencies” (25% of cases from the subgroup), “antibody defects” (31% of cases from the subgroup), “phagocyte defects” (10 % of cases from the subgroup), and “immune dysregulation defects” (50% of cases from the subgroup). The same frequency of occurrence of tissue repair defects: in “combined immunodeficiencies” (16.6% of cases from the subgroup), “autoinflammatory disorders” (26.7% of cases from the subgroup), “phagocyte defects” (10% of cases from the subgroup), in “unverified diagnoses” (20% of cases from the subgroup). The highest percentage of quantitative manifestations of such anomalies as jaw size (26% of cases from the entire study group) and facial dysmorphism (27% of cases from the entire study group). In patients with “combined immunodeficiencies”, all the dental anomalies described in the work were identified. However, the highest percentage of people in this group had delayed teething (33.3%) and facial dysmorphism (33%). The only patient diagnosed with “complement defects” had no dental anomalies. The minimum number of manifestations of the studied anomalies was observed in groups with “antibody defects” and “immune dysregulation defects”. The accumulated experience in describing various dental diagnoses will contribute to the creation of dental criteria for the diagnosis of primary immunodeficiencies.

Crystallization of smooth amorphous calcium phosphate microspheres to core-shell hydroxyapatite microspheres.

Calcium phosphates (Ca-P) represent a significant class of biological minerals found in natural hard tissues. Crystallization through phase transformation of a metastable precursor is an effective strategy to guide the growth of crystalline Ca-P with exceptional functionality. Despite extensive research on Ca-P, the exact process during the crystallization of amorphous particles to hydroxyapatite (HA) remains elusive. Herein, pure HA microspheres with a core-shell structure are crystallized via dissolution and re-crystallization of smooth amorphous calcium phosphate (ACP) microspheres. The transformation is initiated with the increase of the hydrothermal treatment time in the presence of sodium trimetaphosphate and l-glutamic. The underlying mechanisms along with the kinetics of such transformation are explored. Nanocrystalline areas are formed on the smooth ACP microspheres and crystallization advances via nanometre-sized clusters formed by directional arrangement of nanocrystalline whiskers. Our findings shed light on a crucial but unclear stage in the genesis of HA crystals, specifically under the conditions of hydrothermal synthesis.

Endodontic surgery and platelet concentrates: A comprehensive review.

While autologous platelet concentrates (APCs) have gained traction as promising regenerative materials in recent years, their impact on wound healing and tissue regeneration in periapical hard tissue defects remains controversial. Endodontic microsurgery (EMS) has embraced the potential of platelet concentrates, particularly L-PRF (Leucocyte-Platelet-Rich Fibrin) and PRP (Platelet-Rich Plasma), as regenerative tools. These concentrates, rich in growth factors and other bioactive molecules, are thought to enhance healing and treatment outcomes for various endodontic conditions. However, their effectiveness remains a subject of investigation. Despite encouraging 3-D cone beam computed tomography (CBCT) based evidence for PRP's effectiveness in complex lesions and apico-marginal defects, inconsistencies in its performance across preparation and application protocols raise questions about its superiority over existing options. More research is crucial to understand its full potential as a reliable regenerative tool in endodontics. L-PRF and its derivatives are particularly effective in treating apical-marginal defects. It enhances clinical attachment levels and reduces probing pocket depths, likely due to its slow and coordinated release of various growth factors. L-PRF has been shown to also improve patients' quality of life by reducing postoperative swelling and pain. However, more research is needed to standardize its preparation methods and confirm its long-term benefits. This paper aims to provide a comprehensive review of the current knowledge and recent advances in endodontic surgery and the use of platelet concentrates, focusing on their roles in managing periapical lesions and endo-perio lesions.

Immediate single-tooth implant placement in bony defect sites: A 10-year randomized controlled trial.

It is unclear whether an intact buccal bony plate is a prerequisite for immediate implant placement in postextraction sockets. The aim of this 10-year randomized controlled trial was to compare peri-implant soft and hard tissue parameters, esthetic ratings of, and patient-reported satisfaction with immediate implant placement in postextraction sockets with buccal bony defects ≥5mm in the esthetic zone versus delayed implant placement after alveolar ridge preservation. Patients presenting a failing tooth in the esthetic region and a buccal bony defect ≥5mm after an extraction were randomly assigned to immediate (Immediate Group, n=20) or delayed (Delayed Group, n=20) implant placement. The second-stage surgery and provisional restoration placement occurred 3months after implant placement in both groups, followed by definitive restorations 3months thereafter. During a 10-year follow-up period, marginal bone levels (primary outcome), buccal bone thickness, soft tissue parameters, esthetics, and patient-reported satisfaction were recorded. The mean marginal bone level change was -0.71±0.59mm and -0.36±0.39mm in the Immediate Group and the Delayed Group after 10years (p=0.063), respectively. The secondary outcomes were not significantly different between both groups. Marginal bone level changes, buccal bone thickness, clinical outcomes, esthetics, and patients' satisfaction following immediate implant placement, in combination with bone augmentation in postextraction sockets with buccal bony defects ≥5mm, were not statistically different to those following delayed implant placement after ridge preservation in the esthetic zone. Immediate implant placement in case of a failing tooth is a favorable treatment option for patients because it considerably shortens treatment time and the number of surgical treatments. The question is if an intact buccal bone wall is necessary for immediate implant placement. A 10-year study was performed in which 20 patients with a failing tooth in the frontal region of the upper jaw were treated with immediate implant placement and were compared with 20 patients in whom a more conventional treatment strategy was followed in which the failing tooth was first removed and the bone gap restored and the implant placed in a second step. After a 10-year follow-up period, it appeared that the bone around the implant was very stable, gums were healthy, and patients were very satisfied with the result. There was no difference between the two treatment procedures. Such results mean that professionals can discuss the procedure with the patient and apply the individual's preference.

Human collagen sequence polypeptides mediated biomineralization and its molecular mechanism

Biotechnology provides alternatives for regenerative medicine with more controllable functions. Herein, the polypeptides encoded with human collagen I amino-acid sequences were studied for the first time to modulate biomimetic hydroxyapatite (HAP). With a length of 50–100 nm and a width of 20–30 nm, the HAP crystal formed was plate-like. The interaction of the human collagen sequence polypeptide on the (001), (100), and (211) crystal faces of HAP crystal had been studied using Molecular Dynamics (MD) simulations, respectively. Based on MD simulations, van der Waals forces and hydrogen bonds are the main interactions between polypeptides and HAP through the –NH2, –CH2–, –OH, and –COOH, respectively. According to the calculated results, der Waals forces might be the main interaction. The human collagen sequence polypeptides exhibited the highest adsorption energy on the (001) plane of HAP, significantly higher than any of the adsorption energy on the (100) and (211) planes. Therefore, the growth of the (001) would be inhibited, which kept accurate with the result of images from the Transmission Electron Microscope (TEM). Study results provide a basis for rational designing of peptides with human collagen sequences to regenerate hard tissues.

Controlled release in sodium alendronate/halloysite/hydroxyapatite/gelatin nanocomposite scaffolds: A new insight into bone tissue engineering

The use of smart scaffolds with drug release capabilities is now widely recognized as a key approach in designing hard tissue substitutes. In this study, alendronate sodium (AL) was bound to halloysite nanotube (HNT) sheets through ionic and π-π interactions. Hydroxyapatite (HA) powder was synthesized using the co-precipitation method, and the drug/carrier complex was subsequently incorporated into a hydroxyapatite/gelatin (GEL) matrix. Composite scaffolds of GEL/HA/HNT/AL were then created using a freeze-drying technique. Different concentrations of HNT (0.5 %, 1 %, and 2 %) were tested to determine the optimal formulation. The scaffolds were subjected to extensive physical, chemical, and mechanical evaluations using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), compressive stress tests, and measurements of density and porosity. The release profile of alendronate sodium, scaffold swelling behavior in water, bioactivity, and in vitro performance were thoroughly assessed. Cell viability was tested using the MTT assay, while alkaline phosphatase (ALP) activity and cell adhesion studies were performed to evaluate osteogenic potential. The results revealed that the GEL/HA/1 % HNT/AL nanocomposite scaffold exhibited excellent properties, including efficient drug release, optimal swelling rates, and enhanced bioactivity. The MTT assay confirmed high cell viability, and both ALP activity and cell adhesion studies indicated strong potential for bone cell differentiation and repair. Thus, the GEL/HA/1 % HNT/AL nanocomposite scaffold is a highly promising platform for bone tissue engineering.

Investigation of Morphological Changes of the Soft Tissue in the Aesthetic Zone: A 3D Virtual Analysis after Conventional Tooth Extraction and Benex® Extraction.

Postoperative resorption of hard and soft tissues occurs as a consequence of tooth extraction. The Benex®-Control extractor allows minimally invasive extraction of the tooth without causing pronounced iatrogenic trauma. The aim of this study was to verify whether the resorption of the tissues after extraction can be reduced by using the Benex® system compared to the conventional extraction method. Postoperative intraoral scans were superimposed after surgery (t0), after 7 days (t1), after 14 days (t2), after 30 days (t3), after 60 days (t4), and after 90 days (t5) within the two groups (study n = 14, control n = 16), and defined regions of interest (ROIs) (1-8) and volume changes were analyzed. In addition, the influence of gingival thickness and the thickness of the labial cortical plate was investigated. The greatest decrease in volume was observed in both groups in ROI3, although there was no significant difference observed between the groups. In the presence of an adjacent tooth, there was less volume loss in the affected ROIs (1, 2 and 7, 8). The thickness of the gingiva and the bony lamella did not significantly influence the change in volume. Due to the small cohort, the results are limited, and the hypothesis is rejected.

The effect of laser therapy for the treatment of dentin hypersensitivity on surface roughness and bacterial adhesion

The aim of the study was to measure the degree of dentine surface roughness caused by five distinct lasers used to treat dentine hypersensitivity, as well as to evaluate the subsequent bacterial colonization on these irradiated surfaces. Sixty human maxillary premolar teeth without caries or restoration which were extracted for periodontal reasons were used in this study. Five different types of lasers were applied to the root dentin surface. Tested samples were divided into six groups of 10 samples each; control, diode (810 nm), diode (980 nm), Nd: YAG, Er: YAG, and Er, Cr: YSGG laser groups. The arithmetic mean of the surface roughness values (Ra) and the average roughness over a measurement area (Sa) were measured pre- and post-application using any of the laser types. Swab samples were then collected from the dentin surface. Following a 24-hour incubation period at 37 °C, the colony forming units were counted using a stereoscope. The results demonstrated a statistically significant difference in the surface roughness values pre- and post-application (Ra and Sa, respectively) in the Er, Cr: YSGG laser group (p = 0.037,p = 0.007). No significant difference was observed in the other groups (p > 0.05). There was no statistically significant difference in the number of bacterial colonies observed between the test and control groups. Diode and Nd: YAG lasers showed either a decrease or no change in surface roughness; however, the hard tissue lasers (Er: YAG, Er, Cr: YSGG) showed an increase. The Er: YAG and Nd: YAG laser groups exhibited decreased bacterial adhesion compared to the other groups.

Advanced Bioceramics: Properties, Fabrication and Applications

Bioceramics are engineered materials that achieve their applications in the medical field. Bioceramics are promising inorganic materials to create scaffolds for bone regeneration due to their desirable properties, such as biocompatibility, osteoconduction, and their similarity with bone composition. Bioceramics can operate as tissue replacement and can be used for coating metal implants to increase their biocompatibility. Bioceramics are classified into three types: bioinert ceramics, bioactive bioceramics, and biodegradable ceramics. There are different methods for the fabrication of bioceramics, they can be prepared by conventional powder processing methods or by some new unconventional methods. Bioceramics can be fabricated by a sintering process, which takes place through the hardening of the green bodies at a relatively high temperature lower than their melting point. Nowadays, microwave sintering is excellent in both heating efficiency, saving energy and time, and the concomitant processing cost. There are other methods used to obtain bioceramics; such as sol-gel, gas-foaming, gel-casting, and freeze-casting techniques. Recently, the CAD/CAM technique (computer-aided design/manufacture) was used in the fabrication of bioceramics and is applied in the dentistry field. The application of bioceramics connects to the repair of the skeletal system, which consists of joints, bones, and teeth, as well as both soft and hard tissues. Bioceramics can be used to replace parts of the cardiovascular system, especially heart valves.

Injectable Dual Fenton/Enzymatically Cross-Linked Double-Network Hydrogels Based on Acrylic/Phenolic Polymers with Highly Reinforced and Tunable Mechanical Properties.

Injectable hydrogels have been extensively used as promising therapeutic scaffolds for a wide range of biomedical applications, such as tissue regeneration and drug delivery. However, their low fracture toughness and brittleness often limit their scope of application. Double-network (DN) hydrogel, which is composed of independently cross-linked rigid and ductile polymer networks, has been proposed as an alternative technique to compensate for the weak mechanical properties of hydrogels. Nevertheless, some challenges still remain, such as the complicated and time-consuming process for DN formation, and the difficulty in controlling the mechanical properties of DN hydrogels. In this study, we introduce a simple, rapid, and controllable method to prepare in situ cross-linkable injectable DN hydrogels composed of acrylamide (AAm) and 4-arm-PPO-PEO-tyramine (TTA) via dual Fenton- and enzyme-mediated reactions. By varying the concentration of Fenton's reagent, the DN hydrogels were rapidly formed with controllable gelation rate. Importantly, the DN hydrogels showed a 13-fold increase in compressive strength and a 14-fold increase in tensile strength, compared to the single network hydrogels. The mechanical properties, elasticity, and plasticity of DN hydrogels could also be modulated by simply varying the preparation conditions, including the cross-linking density and reagent concentrations. At low cross-linker concentration (<0.05 wt %), the plastic DN hydrogel stretched to over 6,500%, whereas high cross-linker concentration (≥0.05 wt %) induced fully elastic hydrogels, without hysteresis. Besides, DN hydrogels were endowed with rapid self-recovery and highly enhanced adhesion, which can be further applied to wearable devices. Moreover, human dermal fibroblasts treated with DN hydrogels retained viability, demonstrating the biocompatibility of the cross-linking system. Therefore, we expect that the dual Fenton-/enzyme-mediated cross-linkable DN hydrogels offer great potential as advanced biomaterials applied for hard tissue regeneration and replacement.

Validation of a novel AI-based automated multimodal image registration of CBCT and intraoral scan aiding presurgical implant planning.

The objective of this study is to assess accuracy, time-efficiency and consistency of a novel artificial intelligence (AI)-driven automated tool for cone-beam computed tomography (CBCT) and intraoral scan (IOS) registration compared with manual and semi-automated approaches. A dataset of 31 intraoral scans (IOSs) and CBCT scans was used to validate automated IOS-CBCT registration (AR) when compared with manual (MR) and semi-automated registration (SR). CBCT scans were conducted by placing cotton rolls between the cheeks and teeth to facilitate gingival delineation. The time taken to perform multimodal registration was recorded in seconds. A qualitative analysis was carried out to assess the correspondence between hard and soft tissue anatomy on IOS and CBCT. In addition, a quantitative analysis was conducted by measuring median surface deviation (MSD) and root mean square (RMS) differences between registered IOSs. AR was the most time-efficient, taking 51.4 ± 17.2 s, compared with MR (840 ± 168.9 s) and SR approaches (274.7 ± 100.7 s). Both AR and SR resulted in significantly higher qualitative scores, favoring perfect IOS-CBCT registration, compared with MR (p = .001). Additionally, AR demonstrated significantly superior quantitative performance compared with SR, as indicated by low MSD (0.04 ± 0.07 mm) and RMS (0.19 ± 0.31 mm). In contrast, MR exhibited a significantly higher discrepancy compared with both AR (MSD = 0.13 ± 0.20 mm; RMS = 0.32 ± 0.14 mm) and SR (MSD = 0.11 ± 0.15 mm; RMS = 0.40 ± 0.30 mm). The novel AI-driven method provided an accurate, time-efficient, and consistent multimodal IOS-CBCT registration, encompassing both soft and hard tissues. This approach stands as a valuable alternative to manual and semi-automated registration approaches in the presurgical implant planning workflow.

A pilot study on post-mortem determination of drug abuse on dental tissues

BackgroundPost-mortem toxicology constantly deals with the research of reliable alternative matrices to be applied in case of highly damaged corpses (such us carbonized, skeletonized, human remains, etc.). Teeth represent a promising alternative matrix since dental tissues are endowed by different features, resistance and stability after death. ScopeSince scant literature reported on the pharmacokinetics and mechanism of incorporation of xenobiotics into dental tissues, this pilot research aims to investigate whether in the pulp can be detected the same substances found in blood in drug related death cases. Secondly, the study is addressed to disclose the possible deposit of drugs in dental hard tissues (dentine and/or enamel), thus contributing to reconstruct the drug abuse history (timing, e.g.). Materials and methodsThe study experimented with a novel method to separately analyse dental enamel, dentin, and pulp, applied to 10 teeth collected during autopsies of drug-related deaths along with blood and hair samples for classic toxicological analyses. Each tooth was prepared by “pulverization technique” and then analysed by gas chromatography paired with mass spectrometry (GC-MS) and ultra high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC/HR-MS) for searching cocaine, opiates, and metabolites. The results were then compared with those obtained from blood and hair samples. ResultsPreliminary results demonstrated that teeth differ from any other classic matrix (blood and hairs) since the qualitative correspondence of the detected substances between pulp and blood as well as dental hard tissues and hair suggests that they can be useful in post-mortem evaluation as a unique matrix for both acute and chronic assumptions of drugs. The mechanism of accumulation of substances in mineralized dental tissues emerged the most significant result, being influenced by the type of molecule and the method of assumption. The main limitation of this study is the limited availability of the sample and the absence of anamnestic information of the time, rates and method of drug assumption during life. Further research is necessary to systematically investigate the distribution of different substances within the different tissues of the tooth.

Structural, mechanical and in vitro studies on pulsed laser deposition of hydroxyapatite on additive manufactured polyamide substrate

Additive manufacturing (AM) is an emerging field that merges engineering and life sciences to produce components that can effectively act as a replacement in the human body. This AM encompasses biofabrication using cells, biological or biomaterials as building blocks to fabricate biological and bio-application oriented substance, device and therapeutic products through a broad range of engineering and biological processes. Furthermore, bioactive coating on BAM surface facilitates biological fixation between the prosthesis and the hard tissue which increases the long term stability and integrity of the implant. In this paper, hydroxyapatite (HA) powder was coated over AM polyamide substrate using pulsed laser deposition. Coating morphology was characterised using scanning electron microscope (SEM) analysis and observed that the coating was dominated by the presence of particle droplet with different sizes. Compounds like tricalcium phosphate and a few amorphous calcium phosphates were found along with HA which was confirmed by X-ray diffraction (XRD) analysis. Fourier transform infrared spectroscopy (FTIR) techniques shows the presence of phosphate and carbonate groups in the HA structure. Nano-indentation and pull-out test reveals that the layer was strong enough and withstands higher load before it peels off. In vitro analysis was evaluated with human osteosarcoma MG-63 cells with respect to the cell viability and results shows that the good viability was observed on coated surface due to combinational effect of Ca2+ and PO4 3&amp;minus; ions. The multitude of characterisation conducted on the coating has established that coating polyamide with HA results in a positive combination for an implant.

Study of hard tissues of the tooth crown using scanning electron microscopy and elemental analysis

The introduction of new methodological approaches actualizes research that makes it possible to establish relationships between the elemental composition of hard dental tissues and microscopic analysis data. Using scanning electron microscopy, the nature of the location and size of enamel prisms was revealed, and a description of the structure of the initial and final enamel was given. The zone of the dentino-enamel junction, the location of the dentinal tubules and the composition of the dentin matrix were studied. It has been proven that the content of water, organic matter, sodium and potassium is higher in dentin, and the concentration of magnesium, phosphorus and calcium is higher in enamel.

Extracellular Vesicles from Compression-Loaded Cementoblasts Promote the Tissue Repair Function of Macrophages.

Treatment strategies for hard tissue defects aim to establish a mineralized microenvironment that facilitates tissue remodeling. As a mineralized tissue, cementum shares a similar structure with bone and exhibits an excellent capacity to resist resorption under compression. Macrophages are crucial for mineralized remodeling; however, their functional alterations in the microenvironment of cementum remain poorly understood. Therefore, this study explores the mechanisms by which cementum resists resorption under compression and the regulatory roles of cementoblasts in macrophage functions. As a result, extracellular vesicles from compression-loaded cementoblasts (Comp-EVs) promote macrophage M2 polarization and enhance the clearance of apoptotic cells (efferocytosis) by 2- to 3-fold. Local injection of Comp-EVs relieves cementum destruction in mouse root resorption model by activating the tissue repair function of macrophages. Moreover, Comp-EV-loaded hydrogels achieve significant bone healing in calvarial bone defect. Unexpectedly, under compression, EV secretion in cementoblasts is reduced by half. RNA-Seq analysis and verification reveal that Rab35 expression decreases by 60% under compression, thereby hampering the release of EVs. Rab35 overexpression is proposed as a modification of cementoblasts to boost the yield of Comp-EVs. Collectively, Comp-EVs activate the repair function of macrophages, which will be a potential therapeutic strategy for hard tissue repair and regeneration.