Application of socket-shield technique for immediate implant placement and provisionalization in esthetic zone: a case report and literature review / 口腔疾病防治

Objective@#To investigate the effect of the socket-shield technique (SST) concurrent with immediate implant placement and provisionalization (IIPP) in the aesthetic restoration of anterior teeth.@*Methods@#A case of maxillary anterior tooth stumps with a thin labial bone wall was treated with SST for preservation of labial soft and hard tissue fullness, combined with an immediate implant placement and immediate provisional crown for restoring the shape of the tooth and gingival molding@*Results@#Immediate implant placement and provisionalization restored the morphology and function of the affected tooth in the shortest possible time. The patient's labial soft and hard tissue contours in the affected tooth area were well preserved in the 18-month follow-up after the application of the SST, which presented a better aesthetic result. The literature review indicates that the indications for SST are unrestorable maxillary anterior teeth, whose dental, periodontal and periapical tissues are healthy and intact. In the esthetic zone, root shielding is effective in maintaining the soft and hard tissue contour on the labial side of the implant. However, there is no consensus on the technical details of SST, such as the ideal coronal height and thickness of the shield, and the management of the gap between the shield and the implant. Thus, more clinical studies and histologic evidence are needed to provide a reference for clinical decision-making. In addition, digital technology can improve the accuracy of implant placement and shield preparation.@*Conclusion@#The correct application of SST combined with IIPP in the esthetic zone can ensure esthetic results. However, more high-quality evidence-based medical evidence is needed for its long-term efficacy, and indications should be strictly controlled during clinical application.

Glucose-primed PEEK orthopedic implants for antibacterial therapy and safeguarding diabetic osseointegration.

Diabetic infectious microenvironment (DIME) frequently leads to a critical failure of osseointegration by virtue of its main peculiarities including typical hyperglycemia and pathogenic infection around implants. To address the plaguing issue, we devise a glucose-primed orthopedic implant composed of polyetheretherketone (PEEK), Cu-chelated metal-polyphenol network (hauberk coating) and glucose oxidase (GOx) for boosting diabetic osseointegration. Upon DIME, GOx on implants sostenuto consumes glucose to generate H2O2, and Cu liberated from hauberk coating catalyzes the H2O2 to highly germicidal •OH, which massacres pathogenic bacteria through photo-augmented chemodynamic therapy. Intriguingly, the catalytic efficiency of the coating gets greatly improved with the turnover number (TON) of 0.284 s-1. Moreover, the engineered implants exhibit satisfactory cytocompatibility and facilitate osteogenicity due to the presence of Cu and osteopromotive polydopamine coating. RNA-seq analysis reveals that the implants enable to combat infections and suppress pro-inflammatory phenotype (M1). Besides, in vivo evaluations utilizing infected diabetic rat bone defect models at week 4 and 8 authenticate that the engineered implants considerably elevate osseointegration through pathogen elimination, inflammation dampening and osteogenesis promotion. Altogether, our present study puts forward a conceptually new tactic that arms orthopedic implants with glucose-primed antibacterial and osteogenic capacities for intractable diabetic osseointegration.

Perturbation of mitochondrial dynamics links to the aggravation of periodontitis by diabetes.

Diabetes and periodontitis are prevalent diseases that considerably impact global economy and diabetes is a major risk factor of periodontitis. Mitochondrial dynamic alterations are involved in many diseases including diabetes and this study aims to evaluate their relevance with diabetes aggravated periodontitis. Sixty mice are randomly divided into 4 groups: control, periodontitis, diabetes and diabetic periodontitis. Periodontitis severity is evaluated by alveolar bone loss, inflammation and oxidative stress status. Mitochondrial structural and functional defects are evaluated by the mitochondrial fission/fusion events, mitochondrial reactive oxygen species (ROS) accumulation, complex activities and adenosine triphosphate (ATP) production. Advanced glycation end product (AGE) and Porphyromonas gingivalis are closely related to periodontitis occurrence and development. Human gingival fibroblast cells (HGF-1) are used to investigate the AGE role and lipopolysaccharide (LPS) from Porphyromonas gingivalis (P-LPS) in aggravating diabetic periodontitis by mitochondrial dynamic and function alterations. In vivo, diabetic mice with periodontitis show severe bone loss, increased inflammation and oxidative stress accumulation. Among mice with periodontitis, diabetic mice show worse mitochondrial dynamic perturbations than lean mice, along with fusion protein levels inducing more mitochondrial fission in gingival tissue. In vitro, AGEs and P-LPS co-treatment causes severe.

Hydrogel armed with Bmp2 mRNA-enriched exosomes enhances bone regeneration.

BACKGROUND: Sustained release of bioactive BMP2 (bone morphogenetic protein-2) is important for bone regeneration, while the intrinsic short half-life of BMP2 at protein level cannot meet the clinical need. In this study, we aimed to design Bmp2 mRNA-enriched engineered exosomes, which were then loaded into specific hydrogel to achieve sustained release for more efficient and safe bone regeneration. RESULTS: Bmp2 mRNA was enriched into exosomes by selective inhibition of translation in donor cells, in which NoBody (non-annotated P-body dissociating polypeptide, a protein that inhibits mRNA translation) and modified engineered BMP2 plasmids were co-transfected. The derived exosomes were named ExoBMP2+NoBody. In vitro experiments confirmed that ExoBMP2+NoBody had higher abundance of Bmp2 mRNA and thus stronger osteogenic induction capacity. When loaded into GelMA hydrogel via ally-L-glycine modified CP05 linker, the exosomes could be slowly released and thus ensure prolonged effect of BMP2 when endocytosed by the recipient cells. In the in vivo calvarial defect model, ExoBMP2+NoBody-loaded GelMA displayed great capacity in promoting bone regeneration. CONCLUSIONS: Together, the proposed ExoBMP2+NoBody-loaded GelMA can provide an efficient and innovative strategy for bone regeneration.

The role of mitochondria in the peri-implant microenvironment.

NEW FINDINGS: What is the topic of this review? In this review, we consider the key role of mitochondria in the peri-implant milieu, including the regulation of mitochondrial reactive oxygen species and mitochondrial metabolism in angiogenesis, the polarization of macrophage immune responses, and bone formation and bone resorption during osseointegration. What advances does it highlight? Mitochondria contribute to the behaviours of peri-implant cell lines based on metabolic and reactive oxygen species signalling modulations, which will contribute to the research field and the development of new treatment strategies for improving implant success. ABSTRACT: Osseointegration is a dynamic biological process in the local microenvironment adjacent to a bone implant, which is crucial for implant performance and success of the implant surgery. Recently, the role of mitochondria in the peri-implant microenvironment during osseointegration has gained much attention. Mitochondrial regulation has been verified to be essential for cellular events in osseointegration and as a therapeutic target for peri-implant diseases in the peri-implant microenvironment. In this review, we summarize our current knowledge of the key role of mitochondria in the peri-implant milieu, including the regulation of mitochondrial reactive oxygen species and mitochondrial metabolism in angiogenesis, the polarization of macrophage immune responses, and bone formation and resorption during osseointegration, which will contribute to the research field and the development of new treatment strategies to improve implant success. In addition, we indicate limitations in our current understanding of the regulation of mitochondria in osseointegration and suggest topics for further study.

ROS triggered local delivery of stealth exosomes to tumors for enhanced chemo/photodynamic therapy.

BACKGROUND: Exosomes are recognized as effective platforms for targeted delivery for their high physicochemical stability and biocompatibility. However, most of the exosomes are inevitably and rapidly cleared by mononuclear phagocytic system (MPS) during cancer therapy. How to engineer exosome to enhance the delivery efficiency is being intensively explored. In this study, we have constructed mPEG2000-TK-CP05 decorated exosomes as effective delivery platforms to achieve enhanced photodynamic/chemical cancer therapy. RESULTS: Exosomes were coated with CP05-TK-mPEG2000, in which CP05 is a peptide with high affinity to exosomal CD63 and TK could be cleaved by ROS. The resulted exosomes, namely stealth Exo, were electroporated to load RB (photosensitizer Rose Bengal) and Dox (Doxorubicin). We verified that the Stealth Exo@RB (Stealth Exo additionally loaded with RB) could escape MPS while accumulate in the tumor region efficiently in the xenograft model when laser irradiation conducted locally. Additionally, we revealed that the Stealth Exo serves as an efficient platform for Dox delivery. Dox, together with the RB mediated photodynamic therapy induce tumor cell damage synergistically in the tumor region. Moreover, the proposed switchable stealth exosomes minimized the dose of toxic Dox and thus allowed robust tumor immune response. CONCLUSIONS: Our results indicated that the proposed Stealth Exo greatly improves both the accessibility and efficiency of drug delivery, with minimal chemical or genetic engineering. The proposed Stealth Exo serve as a promising and powerful drug delivery nanoplatform in cancer treatment.

Sigma-1 Receptor and Binding Immunoglobulin Protein Interact with Ulinastatin Contributing to a Protective Effect in Rat Cerebral Ischemia/Reperfusion.

OBJECTIVE: To investigate impact of ulinastatin (UTI) on sigma-1 receptor (σ1R) and binding immunoglobulin protein (BiP) after cerebral ischemia/reperfusion injury. METHODS: The middle cerebral artery occlusion (MCAO) model was used to induce cerebral ischemia/reperfusion injury. Eighty male Sprague Dawley rats were randomly divided into 6 groups: control, MCAO, MCAO+50,000 U/kg UTI, MCAO+100,000 U/kg UTI, MCAO+200,000 U/kg UTI, MCAO+300,000 U/kg UTI. At 24 and 48 hours after MCAO, infarct volume, neurological dysfunction, and grip strength test were measured, and level of σ1R and BiP proteins was further detected using Western blot. Molecular docking assays were carried out to verify interaction between σ1R, BiP, and UTI. The serum concentration of BiP and the binding assay between σ1R, BiP, and UTI were determined using enzyme-linked immunosorbent assay. RESULTS: UTI increased the modified neurological severity score and upregulated σ1R and BiP expression in the cerebral cortex after MCAO. The grip strength of forelimbs increased significantly in the MCAO+200,000 U/kg UTI and MCAO+300,000 U/kg UTI groups compared with the MCAO group, while BiP serum levels remained unchanged. The molecular docking assay indicated putative binding between σ1R, BiP, and UTI. The binding assay also revealed that both σ1R and BiP could be combined with UTI. CONCLUSIONS: UTI displays a neuroprotective effect via upregulation of σ1R and BiP during ischemia/reperfusion injury, suggesting that UTI modulates σ1R and BiP and their interaction may provide a novel insight into potential therapeutic mechanisms for stroke.

Retrospective analysis of adverse reactions and related factors of resin cement dentin adhesive / 口腔疾病防治

Objective@# To investigate the adverse reactions of resin cement used for dentin bonding and its influencing factors.@*Methods@# Patients with dental defects treated with resin cement dentin adhesive for direct composite resin repair or full crown indirect repair were selected as the research objects. The occurrence and causes of adverse reactions, such as dental pulp lesions, soft tissue adverse reactions, and restoration loosening and falling off 7 days, 1 month, 3 months, 6 months, and 1 year after treatment, were analyzed retrospectively.@*Results @# Among the 14 776 teeth of 5 971 patients who used resin cement dentin adhesive, 580 cases (3.93%) had adverse reactions. Univariate analysis showed that the incidence of adverse events was highest in teeth with the "full crowns (fixed partial dentures)" restoration type at 7 days, 1 month, and 12 months after treatment. At 7 days after treatment, the incidence of adverse events was the highest in teeth with a preparation depth of "near pulp after preparation". At 7 days and 3 months after treatment, the incidence of adverse events was the highest in teeth with " dentin conditioner-adhesive-resin" treatment of the bonding surface. Multivariate analysis indicated that pulp perforation and pulp capping after tooth preparation were risk factors for adverse events 7 days after treatment (OR=2.610), and the “dentin primer-adhesive-resin” bonding surface treatment method was a protective factor for adverse events 7 days and 3 months after treatment (OR<1). @*Conclusion@#affect the occurrence of adverse events. pulp perforation, and pulp capping after tooth preparation, and self-etching bonding may contribute to adverse reactions.

Evaluation of the antimicrobial effect of silver ion tubing on dental unit waterlines.

PURPOSE: To assess the antimicrobial effects of silver ion tubing (ST) on dental unit waterlines (DUWLs) and their sustainability over time. METHODS: Six dental chair units (DCUs) equipped with ST and four with common tubing (CT) were included in the study. Repeated flushing with phosphate-buffered saline (PBS) was conducted to dislodge biofilms. Then, genetic analysis of the PBS was performed. The tubing was also detached and scanned under a scanning electron microscope (SEM) to observe the adherent biofilm on the lumen walls. RESULTS: Low bacterial levels were noted in both the CT and ST groups, but biofilm attachment was only observed in the CT group. CLINICAL SIGNIFICANCE: Silver ion tubing exhibited high antibacterial activity by reducing the colonization of pathogens in the dental unit water inhibiting biofilm formation, and showing promise as an efficient infection control method for dental unit waterlines.

Insight Into the Molecular Mechanism of Podophyllotoxin Derivatives as Anticancer Drugs.

Podophyllotoxin (PTOX) is a biologically active compound derived from the podophyllum plant, and both it and its derivatives possess excellent antitumor activity. The PTOX derivatives etoposide (VP-16) and teniposide (VM-26) have been approved by the U.S. Food and Drug Administration (FDA) for cancer treatment, but are far from perfect. Hence, numerous PTOX derivatives have been developed to address the major limitations of PTOX, such as systemic toxicity, drug resistance, and low bioavailability. Regarding their anticancer mechanism, extensive studies have revealed that PTOX derivatives can induce cell cycle G2/M arrest and DNA/RNA breaks by targeting tubulin and topoisomerase II, respectively. However, few studies are dedicated to exploring the interactions between PTOX derivatives and downstream cancer-related signaling pathways, which is reasonably important for gaining insight into the role of PTOX. This review provides a comprehensive analysis of the role of PTOX derivatives in the biological behavior of tumors and potential molecular signaling pathways, aiming to help researchers design and develop better PTOX derivatives.

Thrombin inhibitor argatroban modulates bone marrow stromal cells behaviors and promotes osteogenesis through canonical Wnt signaling.

AIMS: Coagulation is a common event that play a double-edged role in physiological and pathological process. Anti-coagulation methods were applied in joint surgery or scaffolds implantation to encourage new vascular formation and avoid coagulation block. However, whether anti-coagulation drug perform regulatory roles in bone structure is unknown. This study aims to explore a direct thrombin inhibitor, argatroban, effects on bone marrow stromal cells (BMSCs) and decipher the underlying mechanisms. MATERIALS AND METHODS: Argatroban effects on BMSCs were investigated in vivo and in vitro. The drug was applied in periodontal disease model mice and bone loss was evaluated by µCT and histology. BMSCs were treated with different doses argatroban or vehicle. Cellular reactions were analyzed using wound healing assay, qRT-PCR, Alizarin Red S staining and western blotting. KEY FINDINGS: We demonstrated that local injection of argatroban can rescue bone loss in periodontal disease in vivo. To explore the underlying mechanism, we examined that cell proliferation and differentiation capability. Proliferation and migration of BMSCs were both inhibited by applying lower dose of argatroban. Interestingly, without affecting osteoclastogenesis, osteogenic differentiation was significantly induced by argatroban, which were shown by extracellular mineralization and upregulation of early osteoblastic differentiation markers, alkaline phosphatase, Osteocalcin, transcription factors RUNX2 and Osterix. In addition, molecular analysis revealed that argatroban promoted ß-catenin nuclear translocation and led to an increase of osteogenesis through activating canonical Wnt signaling. SIGNIFICANCE: Taken together, our results show the novel application of the anti-coagulation compound argatroban in the commitment of BMSCs-based alveolar bone regeneration and remodeling.

[Uprighting a mesially tilted mandibular second molar by using a dental implant as anchorage: a case report].

After tooth has been removed for a long time, adjacent teeth may tilt to occupy the edentulous space, leading to a break in the occlusal 3D equilibrium and a lack of restorative space. This case report presents a mandibular second molar uprighting with anchorage from a dental implant.

[Suggestions for selection and use of masks for dental medical staff during outbreaks of novel coronavirus pneumonia].

During the outbreak of novel coronavirus pneumonia (NCP), dentists are at risk for more severe infection due to their professionalism. This article analyzed the route of infection during diagnosis and treatment of oral diseases. Following the related standards and guidelines of National Health Commission, the types, evaluation index and standards of medical and protective masks were summarized. It is expected to provide certain reference for the selection and use of masks of dental medical staff.

Light stimulus responsive nanomedicine in the treatment of oral squamous cell carcinoma.

Light stimulus responsive therapies are based on a variety of low-toxic therapeutic agents and produce anti-tumor effects only under external light stimulation, thus greatly reducing system toxicity and improving the specificity of treatment. Moreover, light stimulus responsive drug delivery system (DDS) can combine various theranostics molecules to exert synergistic therapeutic effects of various treatments, which has played an important role in cancer treatment. In this review, we introduced the light stimulus responsive cancer therapies including photodynamic therapy (PDT), photothermal therapy (PTT) and light-triggered DDS applied in the treatment of OSCC, described considerable photosensitizers (PSs) and nanomaterials used for oral cancers, which will hope to better the clinic outcome of OSCC patients.

Haptic Rendering of Diverse Tool-Tissue Contact Constraints During Dental Implantation Procedures.

Motor skill learning of dental implantation surgery is difficult for novices because it involves fine manipulation of different dental tools to fulfill a strictly pre-defined procedure. Haptics-enabled virtual reality training systems provide a promising tool for surgical skill learning. In this paper, we introduce a haptic rendering algorithm for simulating diverse tool-tissue contact constraints during dental implantation. Motion forms of an implant tool can be summarized as the high degree of freedom (H-DoF) motion and the low degree of freedom (L-DoF) motion. During the H-DoF state, the tool can move freely on bone surface and in free space with 6 DoF. While during the L-DoF state, the motion degrees are restrained due to the constraints imposed by the implant bed. We propose a state switching framework to simplify the simulation workload by rendering the H-DoF motion state and the L-DoF motion state separately, and seamless switch between the two states by defining an implant criteria as the switching judgment. We also propose the virtual constraint method to render the L-DoF motion, which are different from ordinary drilling procedures as the tools should obey different axial constraint forms including sliding, drilling, screwing and perforating. The virtual constraint method shows efficiency and accuracy in adapting to different kinds of constraint forms, and consists of three core steps, including defining the movement axis, projecting the configuration difference, and deriving the movement control ratio. The H-DoF motion on bone surface and in free space is simulated through the previously proposed virtual coupling method. Experimental results illustrated that the proposed method could simulate the 16 different phases of the complete implant procedures of the Straumann® Bone Level(BL) Implants Φ4.8-L12 mm. According to the output force curve, different contact constraints could be rendered with steady and continuous output force during the operation procedures.

Uprighting a mesially tilted mandibular left second molar with anchorage from a dental implant.

Mesial tilting of adjacent teeth may appear after the removal of a tooth, leading to a lack of restorative space. This dental technique presents a method of uprighting a mesially tilted adjacent tooth by using a dental implant as anchorage.

Susceptibility of Multiple Primary Cancers in Patients With Head and Neck Cancer: Nature or Nurture?

Multiple primary cancers (MPCs) are major obstacles to long-term survival in head and neck cancer (HNSCC), however, the molecular mechanism underlying multiple carcinogenesis remains unclear. "Field cancerization" is a classical theory to elaborate the malignant progression of MPCs. Apart from environmental and immune factors, genetic factors may have great potential as molecular markers for MPCs risk prediction. This review focuses on inherited and acquired gene mutations in MPCs, including germ-line mutation, single-nucleotide polymorphism, chromosomal instability, microsatellite instability and DNA methylation. And definition and prognosis of MPCs have also been discussed. These may pave the way for the early detection, prevention and effective treatment of MPCs in HNSCC.

Minimal invasive microscopic tooth preparation in esthetic restoration: a specialist consensus.

By removing a part of the structure, the tooth preparation provides restorative space, bonding surface, and finish line for various restorations on abutment. Preparation technique plays critical role in achieving the optimal result of tooth preparation. With successful application of microscope in endodontics for >30 years, there is a full expectation of microscopic dentistry. However, as relatively little progress has been made in the application of microscopic dentistry in prosthodontics, the following assumptions have been proposed: Is it suitable to choose the tooth preparation technique under the naked eye in the microscopic vision? Is there a more accurate preparation technology intended for the microscope? To obtain long-term stable therapeutic effects, is it much easier to achieve maximum tooth preservation and retinal protection and maintain periodontal tissue and oral function health under microscopic vision? Whether the microscopic prosthodontics is a gimmick or a breakthrough in obtaining an ideal tooth preparation should be resolved in microscopic tooth preparation. This article attempts to illustrate the concept, core elements, and indications of microscopic minimally invasive tooth preparation, physiological basis of dental pulp, periodontium and functions involved in tool preparation, position ergonomics and visual basis for dentists, comparison of tooth preparation by naked eyes and a microscope, and comparison of different designs of microscopic minimally invasive tooth preparation techniques. Furthermore, a clinical protocol for microscopic minimally invasive tooth preparation based on target restorative space guide plate has been put forward and new insights on the quantity and shape of microscopic minimally invasive tooth preparation has been provided.

A three-dimensional finite element analysis of mechanical function for 4 removable partial denture designs with 3 framework materials: CoCr, Ti-6Al-4V alloy and PEEK.

Polyetheretherketone (PEEK) is a new material used for the frameworks of removable partial dentures (RPD). The questions whether the PEEK framework has similar stress distribution on oral tissue and displacement under masticatory forces as titanium alloy (Ti-6Al-4V) or cobalt-chromium alloy (CoCr) remain unclear and worth exploring. A patient's intraoral data were obtained via CBCT and master model scan. Four RPDs were designed by 3Shape dental system, and the models were processed by three-dimensional finite element analysis. Among three materials tested, PEEK has the lowest maximum von Mises stress (VMS) on periodontal ligament (PDL), the greatest maximum VMS on mucosa, the maximum displacement on free-end of framework, and the lowest maximum VMS on framework. Results suggested that PEEK framework has a good protective effect on PDL, suggesting applications for patients with poor periodontal conditions. However, the maximum displacement of the free-end under masticatory force is not conducive for denture stability, along with large stress on the mucosa indicate that PEEK is unsuitable for patients with more loss of posterior teeth with free-end edentulism.

[Minimal invasive microscopic tooth preparation based on endodontic, periodontal and functional health].

Tooth preparation is the primary and core operation technique for dental esthetic restoration treatment, due to its effect of providing restoration space, bonding interfaces and marginal lines for dental rehabilitation after tooth tissue reduction. The concept of microscopic minimal invasive dentistry put forward the issue of conducting high-quality tooth preparation, conserve tooth-structure, protect vital pulp and periodontal tissue simultaneously. This study reviewed the concepts, physiology background, design and minimal invasive microscopic tooth preparation, and in the meantime, individualized strategies and the two core elements of tooth preparation (quantity and shape) are listed.