Hard tissue stability outside the buccal bone arch contour after guided bone regeneration in the anterior maxilla: A retrospective cohort radiographic study.

OBJECTIVES: To radiographically evaluate the stability of the bone substitute augmented outside the buccal bony arch contour in the maxillary esthetic zone. MATERIALS AND METHODS: Patients who missed a single anterior tooth and received simultaneous GBR in implant surgery were included. The contralateral homonymous area of the implant site was horizontally mirrored as the individual bone arch contour. According to the relative position of the postoperative buccal grafts and bone arch contour at the implant shoulder, 62 patients were allocated into the outside-contour (OC) and inside-contour (IC) groups. Cone-beam computed tomography was performed before surgery, after implant insertion, before re-entry surgery, and at follow-up. The profilometric changes of the buccal bone plate were analyzed via the bone distance to the mirrored bony contour. RESULTS: At the implant shoulder, the bone distance in the OC group was higher than that in the IC group, with statistically significant differences at re-entry surgery and follow-up. However, the bone grafts outside the bone arch contour were reduced into the contour after remodeling and showed more bone resorption than the IC group. At other vertical levels below the implant shoulder, bony grafting of overcontour 1-2 mm range was favorable to regenerate stable bone plates reaching the individual contour at follow-up. CONCLUSIONS: The overaugmented bone outside the buccal bone arch contour tended to remodel into the original contour, which indicates that the anterior bone arch contour is worthy of careful observation for deciding buccolingual implant position and bone augmentation width.

Pegylated carbon nitride nanosheets for enhanced reactive oxygen species generation and photodynamic therapy under hypoxic conditions.

The application of photodynamic therapy (PDT) is of ever-increasing importance in the treatment of malignant tumors; however, there are several major constraints that make it impossible to achieve optimal therapeutic effects. Our objective is to develop a novel photosensitizing drug for skin cancer. In the experiment, we fabricated four-arm-poly ethylene glycol modified amino-rich graphite phase carbon nitride nanosheets (AGCN-PEG), which have good stability in physiological solution and show selective accumulation in tumor cells. Under hypoxic conditions, the AGCN-PEG induced PDT can effectively inhibit growth on A431 human epidermoid carcinoma cells in vivo and in vitro. What's more, after being combined with TMPyP4, the therapeutic effect of AGCN-PEG was greatly improved.

Functional Reconstruction of Mandibular Segment Defects With Individual Preformed Reconstruction Plate and Computed Tomographic Angiography-Aided Iliac Crest Flap.

PURPOSE: With the development of imaging technology and computer-assisted surgery in oral and maxillofacial surgery, digital technology is widely used in vascularized bone flap grafts for mandibular reconstruction. The aim of this study was to use digital technology throughout the treatment process to show that digital techniques can provide a reliable and accurate match between the mandible and the iliac crest flap to achieve functional reconstruction of mandibular segment defects. MATERIALS AND METHODS: Twenty patients underwent 3-dimensional (3D) computed tomography (CT), mirroring technology, 3D model prototyping, and CT angiography (CTA) for treatment planning. Individual preformed reconstruction plates were fabricated and iliac crest flaps were designed preoperatively. After complete resection of the mandibular lesion, the iliac crest flap was shaped to reconstruct the mandibular defects. RESULTS: During follow-up (range, 12 to 36 months), the facial shape, facial symmetry, and mouth opening of all patients recovered well. The 3D CT reconstruction also was evaluated for height, width, length, and bone healing of the iliac crest flap. Postoperative examination showed ideal bone union between the iliac crest flap and the mandible at 6 months. Nine patients received implant-supported fixed dentures to restore dentition. After follow-up, all patients were satisfied with their facial esthetics and function. The new mandible provided a suitable 3D position for implant-supported fixed partial dentures. CONCLUSION: Use of digital techniques throughout the course of treatment improves the predictability and convenience of functional mandibular reconstruction. Individual preformed reconstruction plates and CTA effectively guaranteed the accuracy of iliac flap preparation.

Substrate stiffness regulates arterial-venous differentiation of endothelial progenitor cells via the Ras/Mek pathway.

Cells sense and respond to the biophysical properties of their surrounding environment by interacting with the extracellular matrix (ECM). Therefore, the optimization of these cell-matrix interactions is critical in tissue engineering. The vascular system is adapted to specific functions in diverse tissues and organs. Appropriate arterial-venous differentiation is vital for the establishment of functional vasculature in angiogenesis. Here, we have developed a polydimethylsiloxane (PDMS)-based substrate capable of simulating the physiologically relevant stiffness of both venous (7kPa) and arterial (128kPa) tissues. This substrate was utilized to investigate the effects of changes in substrate stiffness on the differentiation of endothelial progenitor cells (EPCs). As EPCs derived from mouse bone marrow were cultured on substrates of increasing stiffness, the mRNA and protein levels of the specific arterial endothelial cell marker ephrinB2 were found to increase, while the expression of the venous marker EphB4 decreased. Further experiments were performed to identify the mechanotransduction pathway involved in this process. The results indicated that substrate stiffness regulates the arterial and venous differentiation of EPCs via the Ras/Mek pathway. This work shows that modification of substrate stiffness may represent a method for regulating arterial-venous differentiation for the fulfilment of diverse functions of the vasculature.

Effect of tetrahedral DNA nanostructures on proliferation and osteo/odontogenic differentiation of dental pulp stem cells via activation of the notch signaling pathway.

Dental pulp stem cells (DPSCs) derived from the human dental pulp tissue have multiple differentiation capabilities, such as osteo/odontogenic differentiation. Therefore, DPSCs are deemed as ideal stem cell sources for tissue regeneration. As new nanomaterials based on DNA, tetrahedral DNA nanostructures (TDNs) have tremendous potential for biomedical applications. Here, the authors aimed to explore the part played by TDNs in proliferation and osteo/odontogenic differentiation of DPSCs, and attempted to investigate if these cellular responses could be driven by activating the canonical Notch signaling pathway. Upon exposure to TDNs, proliferation and osteo/odontogenic differentiation of DPSCs were dramatically enhanced, accompanied by up regulation of Notch signaling. In general, our study suggested that TDNs can significantly promote proliferation and osteo/odontogenic differentiation of DPSCs, and this remarkable discovery can be applied in tissue engineering and regenerative medicine to develop a significant and novel method for bone and dental tissue regeneration.

Reconstruction of Mandible: A Fully Digital Workflow From Visualized Iliac Bone Grafting to Implant Restoration.

PURPOSE: Although digital aids can help surgeons compensate for the shortcomings of traditional mandibular reconstruction techniques to perform surgery more precisely and effectively, the use of these digital techniques has often been fragmented, divided, and incomplete. This article describes the workflow of a fully digital mandibular reconstruction to explore the proper indications and discusses innovations based on the accuracy and effectiveness of digital techniques. MATERIALS AND METHODS: A restoration-oriented mandibular reconstruction was performed by applying different digital techniques. Preoperative virtual surgery and rapid prototyping were used to aid the vascularized iliac bone graft surgery, which offered a solid basis for the ensuing treatment. Subsequently, implant rehabilitation was accomplished with the assistance of computer-assisted design and manufacture, laser treatment, and selective laser melting techniques. RESULT: The workflow of the fully digital mandibular reconstruction successfully achieved a restoration-oriented treatment. These predictable, accurate, and effective digital techniques improved the consistency of pretreatment design and follow-up treatment. The treatment sequence achieved high predictability and reproducibility owing to the use of digital techniques. CONCLUSION: This study shows that a digital workflow can be predictable, accurate, and effective, which suggests that it could be a valid digital protocol for developing a treatment sequence for patients with jaw defects caused by trauma, congenital anomalies, or mandibular tumor resection.

Visual treatment objective-based lateral esthetics preview for implant-supported reconstruction in terminal dentition with proclined maxillary incisors.

PATIENT: A 67-year-old woman presented with severe periodontitis-induced terminal dentition and proclined maxillary incisor. Three-dimensional facial esthetics-driven computer-assisted virtual tooth rearrangement was performed for implant-supported full-arch reconstruction. The digital workflow combines facial and spiral computed tomography (CT) scans to generate a virtual patient for three-dimensional (3D) facial analysis and obtain a visual treatment objective (VTO)-based lateral esthetic preview for virtual teeth rearrangement. Subsequently, this printed interim denture performed well in functionalization and esthetics, acted as a transitional removable denture, radiological template, and implant-supported interim denture, and guided the design of the final restoration. DISCUSSION: Conventional methods for lateral esthetic preview, such as traditional wax rim try-in, confront difficulties in the treatment of terminal dentition, especially in the presence of proclined maxillary incisors. However, currently available software that aids information fusion and facial analysis can accurately predict soft-to-hard tissue movement and efficiently guide virtual tooth rearrangement for implant-supported full-arch reconstruction. CONCLUSIONS: The use of VTO-based lateral esthetic preview for implant-supported reconstruction improves pre- and postoperative information transfer accuracy and doctor-patient communication efficiency.

Digital workflow in the design of individualized emergence profiles of implant restorations based on the contralateral tooth.

PURPOSE: To describe a novel digital design technique for creating an individualized emergence profile for implant restoration based on the contralateral tooth. METHODS: Cone beam computed tomography (CBCT) data were used to accurately obtain a three-dimensional (3D) model of the contralateral tooth, which was mirror-flipped to design the emergence profile. The emergence profile was further divided into critical and subcritical areas; the critical area precisely replicated the mirror-flipped 3D model, whereas the subcritical area featured a slight concavity on the buccal side, flatness on the lingual side, and slight convexity on the mesial and distal surfaces. Subsequently, a milling machine was used to fabricate healing abutments with individualized emergence profiles. The design of the definitive restoration completely duplicated the emergence profile of the individualized healing abutment and was fabricated using a milling machine. CONCLUSIONS: This technical procedure presents an alternative novel method for designing the emergence profiles of implant restorations, with the potential to improve esthetics and functions as well as to maintain the long-term stability of peri-implant soft and hard tissues.

Minimally invasive techniques for lateral maxillary sinus floor elevation: small lateral window and one-stage surgery-a 2-5-year retrospective study.

This study aimed to introduce a minimally invasive technique for maxillary sinus floor elevation using the lateral approach (lSFE) and to determine the factors that influence the stability of the grafted area in the sinus cavity. Thirty patients (30 implants) treated with lSFE using minimally invasive techniques from 2015 to 2019 were included in the study. Five aspects of the implant (central, mesial, distal, buccal, and palatal bone heights [BHs]) were measured using cone-beam computed tomography (CBCT) before implant surgery, immediately after surgery (T0), 6 months after surgery (T1), and at the last follow-up visit (T2). Patients' characteristics were collected. A small bone window (height, (4.40 ± 0.74) mm; length, (6.26 ± 1.03) mm) was prepared. No implant failed during the follow-up period (3.67 ± 1.75) years. Three of the 30 implants exhibited perforations. Changes in BH of the five aspects of implants showed strong correlations with each other and BH decreased dramatically before second-stage surgery. Residual bone height (RBH) did not significantly influence BH changes, whereas smoking status and type of bone graft materials were the potentially influential factors. During the approximate three-year observation period, lSFE with a minimally invasive technique demonstrated high implant survival rate and limited bone reduction in grafted area. In conclusion, lSFE using minimally invasive techniques was a viable treatment option. Patients who were nonsmokers and whose sinus cavity was filled with deproteinized bovine bone mineral (DBBM) had significantly limited bone resorption in grafted area.

A minimally invasive method for titanium mesh fixation with resorbable sutures in guided bone regeneration: A retrospective study.

OBJECTIVES: Titanium mesh has become a mainstream choice for guided bone regeneration (GBR) owing to its excellent space maintenance. However, the traditional fixation method using titanium screws impacts surgery efficiency and increases patient trauma. We report a novel method of fixing a titanium mesh using resorbable sutures. We assessed the feasibility of resorbable sutures for fixing a titanium mesh and whether it can serve as a stable, universal, and minimally invasive fixation method for a broader application of titanium meshes. METHODS: Patients undergoing GBR with a digital titanium mesh fixed using titanium screws (TS group) and resorbable sutures (RS group) were observed at different time points. The stability of the fixation methods was evaluated on parameters such as titanium mesh spatial displacement, bone augmentation, and bone resorption. RESULTS: A total of 36 patients were included in this study. The exposure rate of the titanium mesh in the TS group was 16.67%, while no exposure was noted in the RS group. There was no significant difference in the parameters of titanium mesh spatial displacement, bone augmentation, and bone resorption between the two groups (p > 0.05). CONCLUSION: The use of resorbable sutures for fixing a titanium mesh can achieve similar results to traditional fixation using titanium screws. Although this new fixation method can improve the efficiency of the surgery and reduce the risk of complications, the long-term clinical effects require further follow-up investigation.

Tetrahedral-Framework Nucleic Acids Carry Small Interfering RNA to Downregulate Toll-Like Receptor 2 Gene Expression for the Treatment of Sepsis.

Sepsis is caused by the invasion of pathogenic microorganisms, which can lead to excessive expression of toll-like receptors (TLRs) in cells and uncontrollable amplification of the inflammatory response. TLR2, as an essential part of the TLR family, has a significant feature in the identification of innate immune responses. Therefore, blocking the expression and activation of TLR2 can inhibit the synthesis and release of inflammatory factors and avoid the occurrence of excessive inflammatory reactions. Small interfering RNA (siRNA) can selectively target the silencing or downregulation of pathogenic genes and has the advantages of high specificity, a strong effect, and fewer adverse reactions. However, the application of siRNA is limited by its high molecular weight, poor biostability, and difficulty in passive uptake into cells. Tetrahedral-framework nucleic acid (tFNA) is a new kind of three-dimensional nucleic acid nanomaterial, which has the advantages of good biocompatibility, stable structure, and editability. In this study, we used tFNA as carriers to deliver siRNA-targeting downregulation of TLR2 expression for anti-inflammatory therapy. We show that siRNA can specifically reduce lipopolysaccharide (LPS)-induced TLR2 elevation and reduce release of inflammatory factors in LPS-induced experimental sepsis, which provides a new idea for the prevention and treatment of sepsis.

Tetrahedral Framework Nucleic Acids Reestablish Immune Tolerance and Restore Saliva Secretion in a Sjögren's Syndrome Mouse Model.

As one of the most frequent autoimmune diseases, Sjogren's syndrome (SS) is characterized by overactive lymphocytic infiltration in the exocrine glands, with ensuing dry mouth and dry eyes. Unfortunately, so far, there are no appropriate therapies without causing overall immunosuppression. Tetrahedral framework nucleic acids (tFNAs) were regarded as promising nanoscale materials whose immunomodulatory capabilities have already been verified. Herein, we reveal, for the first time, that tFNAs were utilized to treat SS in female nonobese diabetic (NOD) mice, the animal model used for SS. We proved a 250 nM tFNA treatment was successful in suppressing inflammation and stimulating saliva secretion in NOD mice. Specialised proteins for the secretory function and structure of acinar cells in submandibular glands (SMGs) were restored. It has been the permanent goal for SS treatment to establish immune tolerance and stop disease development. Surprisingly, tFNA treatment guided T cells toward regulatory T cells (Tregs), while suppressing T helper (Th) cell responses. Th cells include Th1, Th17, and follicular helper T (Tfh) cells. Tregs are highly significant in immune tolerance. Inducing Tregs is a promising approach to reestablish immune tolerance. Comparable results were also observed in B cell responses. Reductions in the percentage of germinal center (GC) B cells and plasma cells were detected, and a marked increase in the percentage of regulatory B cells (Bregs) was also noticed. The mechanisms of inducing Tregs may associated with cytokine changes. Changes of T cell subsets, especially changes of Tfh, may influence the differentiation of B cells accordingly. Collectively, our results demonstrated the immunomodulatory capacities of tFNAs once again, which may provide a novel, safe, and effective option for the treatment of SS and other autoimmune diseases.

A novel digital and visualized guided bone regeneration procedure and digital precise bone augmentation: A case series.

BACKGROUND: Although the traditional bone augmentation technology can basically meet the clinical needs at present, the effect of bone augmentation in most cases is related to the experience of the operator. PROPOSE: This study commits to providing a digital solution for precise bone augmentation in the field of oral implantology. MATERIALS AND METHODS: After collecting the data of patients' intraoral scanning and DICOM (digital imaging and communications in medicine), the implant position is digitally designed, and the alveolar bone is digitally augmented around the ideal implant position. On the premise of ensuring that the thickness of labial bone is 2 mm, and there is sufficient alveolar bone 3 to 4 mm apically from the ideal gingival margin for implant placing, we carry out excessive augmentation of 0.5 and 1 mm on the labial bone and alveolar crest, respectively, to compensate for possible bone resorption after 6 months. After 3D printing the reconstructed alveolar bone model, the titanium mesh is trimmed and preformed on the alveolar bone model. Outcomes are reported in terms of mean values (5%-95% percentile values). RESULTS: Thirty implant sites have accepted this novel virtually designed alveolar bone augmentation. Before the second-stage surgery, the average vertical bone gain was 2.48 mm (0.29-6.32), the average horizontal bone gain was 4.11 mm (1.19-8.74), the average height of the residual alveolar bone above the implant platform was 1.44 mm (0.59-2.92), the average thickness of the labial bone width at the implant platform was 2.00 mm (0.93-3.64), the average thickness of the labial bone width at 2 mm apically from the implant platform was 2.74 mm (1.40-5.46). The virtual augmentation of each tooth position was 349.41 mm3 (165.70-482.70), while the actual augmentation of each tooth position was 352.94 mm3 (159.24-501.78), the accuracy of the final actual augmentation reached 95.82% (range from 88.53% to 99.15%). CONCLUSION: This case series suggests that a virtually digital guided bone regeneration (GBR) workflow is precise and controllable. The practicality, safety and effectiveness of this procedure needs to be compared to other bone augmentation procedures in randomized controlled trials.

The protective effect of tetrahedral framework nucleic acids on periodontium under inflammatory conditions.

Periodontitis is a common disease that causes periodontium defects and tooth loss. Controlling inflammation and tissue regeneration are two key strategies in the treatment of periodontitis. Tetrahedral framework nucleic acids can modulate multiple biological behaviors, and thus, their biological applications have been widely explored. In this study, we investigated the effect of tFNAs on periodontium under inflammatory conditions. Lipopolysaccharide and silk ligature were used to induce inflammation in vivo and in vitro. The results displayed that tFNAs decreased the release of pro-inflammatory cytokines and levels of cellular reactive oxygen species in periodontal ligament stem cells, which promoted osteogenic differentiation. Furthermore, animal experiments showed that tFNAs ameliorated the inflammation of the periodontium and protect periodontal tissue, especially reducing alveolar bone absorption by decreasing inflammatory infiltration and inhibiting osteoclast formation. These findings suggest that tFNAs can significantly improve the therapeutic effect of periodontitis and have the great potential significance in the field of periodontal tissue regeneration.

Enriched Au nanoclusters with mesoporous silica nanoparticles for improved fluorescence/computed tomography dual-modal imaging.

OBJECTIVES: Au nanoclusters (AuNCs) have been used widely in fluorescence bio-imaging because of their good fluorescence, small particle size and non-cytotoxicity. AuNCs are also efficient in computed tomography (CT) imaging. Hence, a dual-modal imaging probe can be constructed without any complicated modification processes by exploiting the excellent performance of AuNCs. In the present study, AuNCs were enriched with mesoporous silica nanoparticles (MSNs) to obtain enhanced fluorescence/CT dual-modal imaging, which was capable of acquiring more imaging information for diseases compared with single-mode imaging. MATERIALS AND METHODS: Biocompatible bovine serum albumin (BSA)-capped AuNCs were prepared and loaded into amine-functionalized MSNs to form MSN@AuNCs. BSA-AuNCs, MSNs, and MSN@AuNCs were characterized by ultraviolet-visible (UV-vis) spectra, transmission electron microscopy (TEM), fluorescence spectra, and zeta potential. CT imaging was recorded using micro-CT scanning. Fluorescence imaging was measured using confocal laser scanning microscopy and flow cytometry. RESULTS: The prepared AuNCs and MSNs possessed good properties as previously reported. The fluorescence intensity and CT value of the AuNCs were enhanced after being enriched with MSNs. The nanoparticles were both non-cytotoxic. Confocal laser scanning microscopy and flow cytometry indicated that MSN@AuNCs in CAL-27 cells showed improved fluorescence imaging compared with simple AuNCs at the same concentration. CONCLUSIONS: The results revealed that the strategy of enriching AuNCs with MSNs can obtain highly sensitive fluorescence/CT dual-modal imaging, which indicated the potential of this nanoparticle in the diagnosis and treatment of disease.

Titanium mesh for bone augmentation in oral implantology: current application and progress.

Guided bone regeneration (GBR) is an effective and simple method for bone augmentation, which is often used to reconstruct the alveolar ridge when the bone defect occurs in the implant area. Titanium mesh has expanded the indications of GBR technology due to its excellent mechanical properties and biocompatibility, so that the GBR technology can be used to repair alveolar ridges with larger bone defects, and can obtain excellent and stable bone augmentation results. Currently, GBR with titanium mesh has various clinical applications, including different clinical procedures. Bone graft materials, titanium mesh covering methods, and titanium mesh fixing methods are also optional. Moreover, the research of GBR with titanium mesh has led to multifarious progresses in digitalization and material modification. This article reviews the properties of titanium mesh and the difference of titanium mesh with other barrier membranes; the current clinical application of titanium mesh in bone augmentation; common complications and management and prevention methods in the application of titanium mesh; and research progress of titanium mesh in digitization and material modification. Hoping to provide a reference for further improvement of titanium mesh in clinical application and related research of titanium mesh.

AS1411 aptamer modified carbon dots via polyethylenimine-assisted strategy for efficient targeted cancer cell imaging.

OBJECTIVES: Carbon dots (CDs), as a fascinating class of fluorescent carbon nanomaterials, have been proven to be powerful tools in the field of bioimaging and biosensing due to their small size, suitable photostability and favourable biocompatibility. However, the cellular uptake of free CDs lacks selectivity and the same negative charges as cell membranes may cause inefficient cell internalization. In this study, an efficient detecting and targeting nanosystem was developed based on the DNA aptamer AS1411 modified CDs with polyethyleneimine (PEI) as connecting bridge. MATERIALS AND METHODS: Hydrothermally prepared CDs were assembled with positive-charged PEI, followed by conjugation with AS1411 through electrostatic interaction to form CDs-PEI-AS1411 nanocomplexes. The CDs, CDs-PEI and CDs-PEI-AS1411 were characterized by transmission electron microscopy (TEM), fourier transform infrared (FTIR) spectra, UV-vis spectra, zeta potential measurements and capillary electrophoresis characterizations. The cytotoxicity investigation of the CDs-PEI-AS1411 and CDs-PEI in both MCF-7 and L929 cells was carried out by the CCK-8 assay. The cellular uptake of the CDs-PEI-AS1411 was studied with confocal microscopy and flow cytometry. RESULTS: The as-prepared nanosystem possessed good photostability and no obvious cytotoxicity. On the basis of the confocal laser scanning microscope observation and the flow cytometry studies, the cellular uptake of CDs-PEI-AS1411 nanosystem in MCF-7 cells was significantly higher than that of L929 cells, which revealed the highly selective detection ability of nucleolin-positive cells. CONCLUSIONS: The results of this study indicated that the CDs-PEI-AS1411 nanosystem had a potential value in cancer cell targeted imaging.

Radial P34HB Electrospun Fiber: A Scaffold for Bone Tissue Engineering.

Finding suitable scaffold material is always an enormous challenge in the study of bone tissue engineering. Designing and preparing bone scaffolds with biomimetic properties is also a difficult problem for bone reparation projects. This project intends to fabricate radial bio-plasticpoly-3-hydroxybutyrate-4-hydroxybutyrate (P34HB) electrospun fibers scaffold that mimic structural, compositional and stiffness properties via an electro spinning technique. The surface morphology, hydrophilicity of the radial fibers scaffold were tested, a contact angle meter and a universal material tester. Bone marrow mesenchymal stem cell (BMSC) morphologies on radial P34HB electrospun fibers scaffold were observed after cell culture under fluorescence microscopy. Tests of cell viability on radial P34HB electrospun fibers scaffold were conducted. We further tested the osteogenic differentiation ability of radial fibers scaffold. These results showed that radial P34HB electrospun fibers scaffold have good biosafety, biocompatibility and osteogenic induction. The radial structure of the scaffold also has a strong effect on the induction of bone formation. Moreover, the structure could also improve the bone contact area of the implant and increase the locking and fixation between the implant and the bone. We plan to apply this procedure to animal experiments for bone defect repair in further research.

Design, fabrication and applications of tetrahedral DNA nanostructure-based multifunctional complexes in drug delivery and biomedical treatment.

Although organic nanomaterials and inorganic nanoparticles possess inherent flexibility, facilitating functional modification, increased intracellular uptake and controllable drug release, their underlying cytotoxicity and lack of specificity still cause safety concerns. Owing to their merits, which include natural biocompatibility, structural stability, unsurpassed programmability, ease of internalization and editable functionality, tetrahedral DNA nanostructures show promising potential as an alternative vehicle for drug delivery and biomedical treatment. Here, we describe the design, fabrication, purification, characterization and potential biomedical applications of a self-assembling tetrahedral DNA nanostructure (TDN)-based multifunctional delivery system. First, relying on Watson-Crick base pairing, four single DNA strands form a simple and typical pyramid structure via one hybridization step. Then, the protocol details four different modification approaches, including replacing a short sequence of a single DNA strand by an antisense peptide nucleic acid, appending an aptamer to the vertex, direct incubation with small-molecular-weight drugs such as paclitaxel and wogonin and coating with protective agents such as cationic polymers. These modified TDN-based complexes promote the intracellular uptake and biostability of the delivered molecules, and show promise in the fields of targeted therapy, antibacterial and anticancer treatment and tissue regeneration. The entire duration of assembly and characterization depends on the cargo type and modification method, which takes from 2 h to 3 d.

The application of a newly designed L-shaped titanium mesh for GBR with simultaneous implant placement in the esthetic zone: A retrospective case series study.

BACKGROUND: To our acknowledgment, there were limited clinical studies about the guided bone regeneration (GBR) for both vertical and horizontal augmentation at the same time using titanium mesh (Ti-mesh) with simultaneous implant placement in the esthetic zone. Meanwhile, studies that specially evaluate resorption and long-term stability of the augmented labial bone after loading were also rare. Therefore, this study introduced a newly designed L-shaped Ti-mesh used for GBR with simultaneous implant placement and evaluated the bone augmentation effectiveness, resorption, and long-term stability of peri-implant bone with this newly designed L-shaped Ti-mesh. MATERIALS AND METHODS: Twelve patients (16 implants) who had underwent a GBR procedure using L-shaped Ti-mesh with simultaneous implants placement were reviewed in this study. Complications, implant success, and survival rate were recorded and calculated. Furthermore, the bone gain values, labial bone resorption, and remaining labial bone volume were measured by cone beam CT (CBCT) during 13-41 months follow-up. RESULTS: After GBR using L-shaped Ti-mesh, the average bone gain values were 3.61 ± 1.50 mm vertically and 3.10 ± 2.06 mm horizontally. The implant success and surviving rate were 93.75% and 100%, respectively during the longest 41 months follow-up. The vertical labial bone resorption was -0.81 ± 1.00 mm, horizontal labial bone resorption was -0.13 ± 1.19 mm at the top of the implants. The remaining labial bone thickness was 2.24 ± 1.29 mm at the top of the implants and 2.86 ± 1.08 mm at the 2 mm apically from the implant tops after loading. There was still 1.13 ± 1.18 mm vertical labial bone remaining above the top of implants for approximately 87.5% sites. CONCLUSIONS: GBR using L-shaped Ti-mesh with simultaneous implant placement (one-step surgery) in the esthetic zone could achieve predictable results for vertical and horizontal bone augmentation at the same time. Meanwhile, L-shaped Ti-mesh could preferably reconstruct and reduce the labial bone resorption to achieve long-term esthetics. This newly designed L-shaped Ti-mesh may offer predictable and excellent outcomes for the implant restoration in the esthetic zone.