Obesity/Metabolic Syndrome and Diabetes Mellitus on Peri-implantitis

Experimental models for peri-implant diseases: a narrative review

OBJECTIVES

Peri-implant diseases, being the most common implant-related complications, significantly impact the normal functioning and longevity of implants. Experimental models play a crucial role in discovering potential therapeutic approaches and elucidating the mechanisms of disease progression in peri-implant diseases. This narrative review comprehensively examines animal models and common modeling methods employed in peri-implant disease research and innovatively summarizes the in vitro models of peri-implant diseases.

MATERIALS AND METHODS

Articles published between 2015 and 2023 were retrieved from PubMed/Medline, Web of Science, and Embase. All studies focusing on experimental models of peri-implant diseases were included and carefully evaluated.

RESULTS

Various experimental models of peri-implantitis have different applications and advantages. The dog model is currently the most widely utilized animal model in peri-implant disease research, while rodent models have unique advantages in gene knockout and systemic disease induction. In vitro models of peri-implant diseases are also continuously evolving to meet different experimental purposes.

CONCLUSIONS

The utilization of experimental models helps simplify experiments, save time and resources, and promote advances in peri-implant disease research. Animal models have been proven valuable in the early stages of drug development, while technological advancements have brought about more predictive and relevant in vitro models.

CLINICAL RELEVANCE

This review provides clear and comprehensive model selection strategies for researchers in the field of peri-implant diseases, thereby enhancing understanding of disease pathogenesis and providing possibilities for developing new treatment strategies.

Enhancing angiogenesis in peri-implant soft tissue with bioactive silk fibroin microgroove coatings on zirconia surfaces

Zirconia abutments and restorations have improved the aesthetic appeal of implant restoration, yet peri-implantitis poses a significant threat to long-term success. The soft tissue surrounding implants is a crucial biological barrier against inflammation and subsequent bone loss. Peri-implantitis, akin to periodontitis, progresses rapidly and causes extensive tissue damage. Variations in tissue structure significantly influence disease progression, particularly the lower vascular density in peri-implant connective tissue, compromising its ability to combat infection and provide essential nutrients. Blood vessels within this tissue are vital for healing, with angiogenesis playing a key role in immune defense and tissue repair. Enhancing peri-implant soft tissue angiogenesis holds promise for tissue integration and inflammation control. Microgroove surfaces have shown potential in guiding vessel growth, but using subtractive technologies to carve microgrooves on zirconia surfaces may compromise mechanical integrity. In this study, we utilized inkjet printing to prepare bioactive silk fibroin microgrooves (SFMG) coating with different sizes on zirconia surfaces. SFMG coating, particularly with 90 µm width and 10 µm depth, effectively directed human umbilical vein endothelial cells (HUVECs) along microgrooves, promoting their proliferation, migration, and tube formation. The expression of vascular endothelial growth factor A and fibroblast growth factor in HUVECs growing on SFMG coating was upregulated. Additionally, the SFMG coating activated the PI3K-AKT pathway and increased glycolytic enzyme gene expression in HUVECs. In conclusion, SFMG coating enhances HUVEC growth and angiogenesis potential by activating the PI3K-AKT pathway and glycolysis, showing promise for improving tissue integration and mitigating inflammation in zirconia abutments and restorations.

A whole-course-repair system based on ROS/glucose stimuli-responsive EGCG release and tunable mechanical property for efficient treatment of chronic periodontitis in diabetic rats

Elevated glucose levels, multiple pro-inflammatory cytokines and the generation of excessive reactive oxygen species (ROS) are pivotal characteristics within the microenvironments of chronic periodontitis with diabetes mellitus (CPDM). Control of inflammation and modulation of immune system are required in the initial phase of CPDM treatment, while late severe periodontitis requires a suitable scaffold to promote osteogenesis, rebuild periodontal tissue and reduce alveolar bone resorption. Herein, a whole-course-repair system is introduced by an injectable hydrogel using phenylboronic acid functionalized oxidized sodium alginate (OSA-PBA) and carboxymethyl chitosan (CMC). Epigallocatechin-3-gallate (EGCG) was loaded to simultaneously adjust the mechanical property of the OSA-PBA/CMC + EGCG hydrogel (OPCE). This hydrogel has distinctive adaptability, injectability, and ROS/glucose-triggered release of EGCG, making it an ideal drug delivery carrier. As expected, OPCE hydrogel shows favourable antioxidant and anti-inflammatory properties, along with a regulatory influence on the phenotypic transition of macrophages, providing a favourable immune microenvironment. Apart from that, it provides a favourable mechanical support for osteoblast/osteoclast differentiation regulation at the late proliferation stage of periodontal regeneration. The practical therapeutic effects of OPCE hydrogels were also confirmed when applied for treating periodontitis in diabetic rats. In summary, OPCE hydrogel may be a promising whole-course-repair system for the treatment of CPDM.

Th-Cell Subsets of Submandibular Lymph Nodes in Peri-Implantitis

BACKGROUND

Implant surgery is a popular operation in craniomaxillofacial surgery, but the occurrence of peri-implantitis affects the success and survival rate of the implant. Research has found that Th-cell-related cytokines are associated with peri-implantitis. However, the distribution and proportions of Th-cell subsets in submandibular lymph nodes' immune environments during the progression of peri-implantitis remain unclear.

METHODS

Forty-eight rats were randomly divided into 4 groups: the control group, the 1-week ligation peri-implantitis induction (Lig 1w) group, the Lig 2w group, and the Lig 4w group (n=12). Ligation was maintained for different times to induce peri-implantitis 4 weeks after implantation. Inflammation and bone resorption were examined by clinical probing and micro-CT. The submandibular lymph nodes were harvested for quantitative real-time polymerase chain reaction and flow cytometry to obtain the Th-cell profiles.

RESULTS

With increasing ligation time, more redness and swelling in the gingiva and more bone resorption around the implant were observed (P<0.05). The proportions of Th1 and Th17 cells increased, the proportion of Th2 cells decreased, and the proportion of Treg cells first increased and then decreased in the lymph nodes (P<0.05).

CONCLUSIONS

This study provided a preliminary characterization of the temporal distribution of Th cells in lymph nodes of peri-implantitis. Persistent elevation of Th1 and Th17 proportions and decrease of Treg proportion may be the cause of bone resorption in peri-implantitis. Lymphatic drainage may be a bridge between craniomaxillofacial diseases and systemic diseases. Early immune support against T cells may be a potential therapeutic idea for the prevention of implant failure and the potential risk of systemic disease.

Magnesium promotes vascularization and osseointegration in diabetic states

Diabetes has long been considered a risk factor in implant therapy and impaired wound healing in soft and hard oral tissues. Magnesium has been proved to promote bone healing under normal conditions. Here, we elucidate the mechanism by which Mg2+ promotes angiogenesis and osseointegration in diabetic status. We generated a diabetic mice model and demonstrated the alveolar bone healing was compromised, with significantly decreased angiogenesis. We then developed Mg-coating implants with hydrothermal synthesis. These implants successfully improved the vascularization and osseointegration in diabetic status. Mechanically, Mg2+ promoted the degradation of Kelch-like ECH-associated protein 1 (Keap1) and the nucleation of nuclear factor erythroid 2-related factor 2 (Nrf2) by up-regulating the expression of sestrin 2 (SESN2) in endothelial cells, thus reducing the elevated levels of oxidative stress in mitochondria and relieving endothelial cell dysfunction under hyperglycemia. Altogether, our data suggested that Mg2+ promoted angiogenesis and osseointegration in diabetic mice by regulating endothelial mitochondrial metabolism.

A Dual-Antioxidative Coating on Transmucosal Component of Implant to Repair Connective Tissue Barrier for Treatment of Peri-Implantitis

Since the microgap between implant and surrounding connective tissue creates the pass for pathogen invasion, sustained pathological stimuli can accelerate macrophage-mediated inflammation, therefore affecting peri-implant tissue regeneration and aggravate peri-implantitis. As the transmucosal component of implant, the abutment therefore needs to be biofunctionalized to repair the gingival barrier. Here, a mussel-bioinspired implant abutment coating containing tannic acid (TA), cerium and minocycline (TA-Ce-Mino) is reported. TA provides pyrogallol and catechol groups to promote cell adherence. Besides, Ce3+ /Ce4+  conversion exhibits enzyme-mimetic activity to remove reactive oxygen species while generating O2 , therefore promoting anti-inflammatory M2 macrophage polarization to help create a regenerative environment. Minocycline is involved on the TA surface to create local drug storage for responsive antibiosis. Moreover, the underlying therapeutic mechanism is revealed whereby the coating exhibits exogenous antioxidation from the inherent properties of Ce and TA and endogenous antioxidation through mitochondrial homeostasis maintenance and antioxidases promotion. In addition, it stimulates integrin to activate PI3K/Akt and RhoA/ROCK pathways to enhance VEGF-mediated angiogenesis and tissue regeneration. Combining the antibiosis and multidimensional orchestration, TA-Ce-Mino repairs soft tissue barriers and effector cell differentiation, thereby isolating the immune microenvironment from pathogen invasion. Consequently, this study provides critical insight into the design and biological mechanism of abutment surface modification to prevent peri-implantitis.

Temporal Immunomodulation via Wireless Programmed Electric Cues Achieves Optimized Diabetic Bone Regeneration

Mimicking the temporal pattern of biological behaviors during the natural repair process is a promising strategy for biomaterial-mediated tissue regeneration. However, precise regulation of dynamic cell behaviors allocated in a microenvironment post-implantation remains challenging until now. Here, remote tuning of electric cues is accomplished by wireless ultrasound stimulation (US) on an electroactive membrane for bone regeneration under a diabetic background. Programmable electric cues mediated by US from the piezoelectric membrane achieve the temporal regulation of macrophage polarization, satisfying the pattern of immunoregulation during the natural healing process and effectively promoting diabetic bone repair. Mechanistic insight reveals that the controllable decrease in AKT2 expression and phosphorylation could explain US-mediated macrophage polarization. This study exhibits a strategy aimed at precisely biosimulating the temporal regenerative pattern by controllable and programmable electric output for optimized diabetic tissue regeneration and provides basic insights into bionic design-based precision medicine achieved by intelligent and external field-responsive biomaterials.

Combined Molybdenum Gelatine Methacrylate Injectable Nano-Hydrogel Effective Against Diabetic Bone Regeneration

Introduction

Bone defects in diabetes mellitus (DM) remain a major challenge for clinical treatment. Fluctuating glucose levels in DM patients lead to excessive production of reactive oxygen species (ROS), which disrupt bone repair homeostasis. Bone filler materials have been widely used in the clinical treatment of DM-related bone defects, but overall they lack efficacy in improving the bone microenvironment and inducing osteogenesis. We utilized a gelatine methacrylate (GelMA) hydrogel with excellent biological properties in combination with molybdenum (Mo)-based polyoxometalate nanoclusters (POM) to scavenge ROS and promote osteoblast proliferation and osteogenic differentiation through the slow-release effect of POM, providing a feasible strategy for the application of biologically useful bone fillers in bone regeneration.

Methods

We synthesized an injectable hydrogel by gelatine methacrylate (GelMA) and POM. The antioxidant capacity and biological properties of the synthesized GelMA/POM hydrogel were tested.

Results

In vitro, studies showed that hydrogels can inhibit excessive reactive oxygen species (ROS) and reduce oxidative stress in cells through the beneficial effects of pH-sensitive POM. Osteogenic differentiation assays showed that GelMA/POM had good osteogenic properties with upregulated expression of osteogenic genes (BMP2, RUNX2, Osterix, ALP). Furthermore, RNA-sequencing revealed that activation of the PI3K/Akt signalling pathway in MC3T3-E1 cells with GelMA/POM may be a potential mechanism to promote osteogenesis. In an in vivo study, radiological and histological analyses showed enhanced bone regeneration in diabetic mice, after the application of GelMA/POM.

Conclusion

In summary, GelMA/POM hydrogels can enhance bone regeneration by directly scavenging ROS and activating the PI3K/Akt signalling pathway.

Bone healing around implants placed in subjects with metabolically compromised systemic conditions

The aim of this study was to evaluate the bone healing of tight-fit implants placed in the maxilla and mandible of subjects compromised with metabolic syndrome (MS) and type-2 Diabetes Mellitus (T2DM). Eighteen Göttingen minipigs were randomly distributed into three groups: (i) control (normal diet), (ii) MS (cafeteria diet for obesity induction), (iii) T2DM (cafeteria diet for obesity induction + Streptozotocin for T2DM induction). Maxillary and mandibular premolars and molar were extracted. After 8 weeks of healing, implants with progressive small buttress threads were placed, and allowed to integrate for 6 weeks after which the implant/bone blocks were retrieved for histological processing. Qualitative and quantitative histomorphometric analyses (percentage of bone-to-implant contact, %BIC, and bone area fraction occupancy within implant threads, %BAFO) were performed. The bone healing process around the implant occurred predominantly through interfacial remodeling with subsequent bone apposition. Data as a function of systemic condition yielded significantly higher %BIC and %BAFO values for healthy and MS relative to T2DM. Data as a function of maxilla and mandible did not yield significant differences for either %BIC and %BAFO. When considering both factors, healthy and MS subjects had %BIC and %BAFO trend towards higher values in the mandible relative to maxilla, whereas T2DM yielded higher %BIC and %BAFO in the maxilla relative to mandible. All systemic conditions presented comparable levels of %BIC and %BAFO in the maxilla; healthy and MS presented significantly higher %BIC and %BAFO relative to T2DM in the mandible. T2DM presented lower amounts of bone formation around implants relative to MS and healthy. Implants placed in the maxilla and in the mandible showed comparable amounts of bone in proximity to implants.

The Action of Angiocrine Molecules Sourced from Mechanotransduction-Related Endothelial Cell Partially Explain the Successful of Titanium in Osseointegration

Since Branemark's findings, titanium-based alloys have been widely used in implantology. However, their success in dental implants is not known when considering the heterogenicity of housing cells surrounding the peri-implant microenvironment. Additionally, they are expected to recapitulate the physiological coupling between endothelial cells and osteoblasts during appositional bone growth during osseointegration. To investigate whether this crosstalk was happening in this context, we considered the mechanotransduction-related endothelial cell signaling underlying laminar shear stress (up to 3 days), and this angiocrine factor-enriched medium was harvested further to use exposing pre-osteoblasts (pOb) for up to 7 days in vitro. Two titanium surfaces were considered, as follows: double acid etching treatment (w_DAE) and machined surfaces (wo_DAE). These surfaces were used to conditionate the cell culture medium as recommended by ISO10993-5:2016, and this titanium-enriched medium was later used to expose ECs. First, our data showed that there is a difference between the surfaces in releasing Ti molecules to the medium, providing very dynamic surfaces, where the w_DAE was around 25% higher (4 ng/mL) in comparison to the wo_DAE (3 ng/mL). Importantly, the ECs took up some of this titanium content for up to 3 days in culture. However, when this conditioned medium was used to expose pOb for up to 7 days, considering the angiocrine factors released from ECs, the concentration of Ti was lesser than previously reported, reaching around 1 ng/mL and 2 ng/mL, respectively. Thereafter, pOb exposed to this angiocrine factor-enriched medium presented a significant difference when considering the mechanosignaling subjected to the ECs. Shear-stressed ECs showed adequate crosstalk with osteoblasts, stimulating the higher expression of the Runx2 gene and driving higher expressions of Alkaline phosphatase (ALP), bone sialoprotein (BSP), and osteocalcin. Mechanotransduction-related endothelial cell signaling as a source of angiocrine molecules also stimulated the higher expression of the Col3A1 gene in osteoblasts, which suggests it is a relevant protagonist during trabecular bone growth. In fact, we investigated ECM remodeling by first evaluating the expression of genes related to it, and our data showed a higher expression of matrix metalloproteinase (MMP) 2 and MMP9 in response to mechanosignaling-based angiocrine molecules, independent of considering w_DAE or the wo_DAE, and this profile reflected on the MMP2 and MMP9 activities evaluated via gelatin-based zymography. Complimentarily, the ECM remodeling seemed to be a very regulated mechanism in mature osteoblasts during the mineralization process once both TIMP metallopeptidase inhibitor 1 and 2 (TIMP1 and TIMP2, respectively) genes were significantly higher in response to mechanotransduction-related endothelial cell signaling as a source of angiocrine molecules. Altogether, our data show the relevance of mechanosignaling in favoring ECs' release of bioactive factors peri-implant, which is responsible for creating an osteogenic microenvironment able to drive osteoblast differentiation and modulate ECM remodeling. Taking this into account, it seems that mechanotransduction-based angiocrine molecules explain the successful use of titanium during osseointegration.

Abnormal Decrease of Macrophage ALKBH5 Expression Causes Abnormal Polarization and Inhibits Osteoblast Differentiation

Peri-implant tissue inflammation is an inflammatory injury that occurs in the soft and hard tissues surrounding the implant and is the main cause of short- or long-term failure of implant prosthetic restorations, which is compounded by bone loss and bone destruction in the alveolar bone of diabetes patients with peri-implantitis. However, the mechanisms underlying the persistence of diabetic peri-implantitis, as well as the essential connections and key molecules that regulate its start and progression, remain unknown. In this study, we discovered that M1 macrophage polarization was abnormally enhanced in diabetic peri-implantitis and influenced the osteogenic differentiation of mesenchymal stem cells. RNA sequencing revealed that ALKBH5 expression was abnormally reduced in diabetic peri-implantitis. Further mechanism study showed that ALKBH5 and its mediated m6A can influence osteogenic differentiation, which in turn influences the persistence of diabetic peri-implantitis. Our findings present a new mechanism for the suppression of osteoblast development in diabetic peri-implantitis and a new treatment strategy to promote anabolism by inhibiting ALKBH5.

Nanotube patterning reduces macrophage inflammatory response via nuclear mechanotransduction

The inflammatory immune environment surrounding titanium bone implants determines the formation of osseointegration, and nanopatterning on implant surfaces modulates the immune microenvironment in the implant region. Among many related mechanisms, the mechanism by which nanopatterning controls macrophage inflammatory response still needs to be elucidated. In this paper, we found that inhibition of the nuclear envelope protein lamin A/C by titania nanotubes (TNTs) reduced the macrophage inflammatory response. Knockdown of lamin A/C reduced macrophage inflammatory marker expression, while overexpression of lamin A/C significantly elevated inflammatory marker expression. We further found that suppression of lamin A/C by TNTs limited actin polymerization, thereby reducing the nuclear translocation of the actin-dependent transcriptional cofactor MRTF-A, which subsequently reduced the inflammatory response. In addition, emerin, which is a key link between lamin A/C and actin, was delocalized from the nucleus in response to mechanical stimulation by TNTs, resulting in reduced actin organization. Under inflammatory conditions, TNTs exerted favourable osteoimmunomodulatory effects on the osteogenic differentiation of mouse bone marrow-derived stem cells (mBMSCs) in vitro and osseointegration in vivo. This study shows and confirms for the first time that lamin A/C-mediated nuclear mechanotransduction controls macrophage inflammatory response, and this study provides a theoretical basis for the future design of immunomodulatory nanomorphologies on the surface of metallic bone implants.

Do Systemic Diseases and Medications Influence Dental Implant Osseointegration and Dental Implant Health? An Umbrella Review

The aim of this umbrella review is to evaluate what are the most common medications and systemic diseases that can affect bone-implant integration, the success rate and survival rate of dental implants, peri-implant tissue health, and implant loss. Systematic reviews, with meta-analysis or not, about how systemic diseases and medications influence dental implant osseointegration, survival rate, success rate, and peri-implant diseases, published only in the English language, are electronically searched across the most important scientific databases. The present umbrella review includes eight systematic reviews, and osteoporosis and diabetes are the most investigated pathologies. Systemic diseases, such as neurologic disorders, HIV, hypothyroidism, cardiovascular diseases, and drugs, such as beta blockers, anti-hypertensives, or diuretics do not show a decreased rate of implant osseointegration. It seems that drugs, such as proton-pump inhibitors (PPIs) or serotonin reuptake inhibitors (SSRIs), negatively affect implant osseointegration. Few studies compare the effects of drugs and systemic diseases on the parameters considered in this overview. It is important to underline how the results of this review need to be validated with subsequent and more reviews.

Nanohydroxyapatite-Coated Titanium Surface Increases Vascular Endothelial Cells Distinct Signaling Responding to High Glucose Concentration

Aim: The success of dental implants depends on osseointegration can be compromised by well-known related adverse biological processes, such as infection and diabetes. Previously, nanohydroxyapatite-coated titanium surfaces (nHA_DAE) have been shown to contain properties that promote osteogenesis by enhancing osteoblast differentiation. In addition, it was hypothesized to drive angiogenesis in high-glucose microenvironments, mimicking diabetes mellitus (DM). On the other hand, the null hypothesis would be confirmed if no effect was observed in endothelial cells (ECs). Materials and methods: Titanium discs presenting the differential surfaces were previously incubated in an FBS-free cell culture medium for up to 24 h, which was, thereafter, supplemented with 30.5 mM of glucose to expose human umbilical vein endothelial cells (HUVECs, ECs) for 72 h. They were then harvested, and the sample was processed to provide molecular activity of specific genes related to EC survival and activity by using qPCR, and the conditioned medium by ECs was used to evaluate the activity of matrix metalloproteinases (MMPs). Results: Our data guaranteed better performance of this nanotechnology-involved titanium surface to this end once the adhesion and survival characteristics were ameliorated by promoting a higher involvement of β1-Integrin (~1.5-fold changes), Focal Adhesion Kinases (FAK; ~1.5-fold changes) and SRC (~2-fold changes) genes. This signaling pathway culminated with the cofilin involvement (~1.5-fold changes), which guaranteed cytoskeleton rearrangement. Furthermore, nHA_DAE triggered signaling that was able to drive the proliferation of endothelial cells once the cyclin-dependent kinase gene was higher in response to it, while the P15 gene was significantly down-regulated with an impact on the statement of angiogenesis. Conclusions: Altogether, our data show that a nanohydroxyapatite-coated titanium surface ameliorates the EC performance in a high-glucose model in vitro, suggesting its potential application in DM patients.

Adipogenesis-Related Metabolic Condition Affects Shear-Stressed Endothelial Cells Activity Responding to Titanium

PURPOSE

Obesity has increased around the world. Obese individuals need to be better assisted, with special attention given to dental and medical specialties. Among obesity-related complications, the osseointegration of dental implants has raised concerns. This mechanism depends on healthy angiogenesis surrounding the implanted devices. As an experimental analysis able to mimic this issue is currently lacking, we address this issue by proposing an in vitro high-adipogenesis model using differentiated adipocytes to further investigate their endocrine and synergic effect in endothelial cells responding to titanium.

MATERIALS AND METHODS

Firstly, adipocytes (3T3-L1 cell line) were differentiated under two experimental conditions: Ctrl (normal glucose concentration) and High-Glucose Medium (50 mM of glucose), which was validated using Oil Red O Staining and inflammatory markers gene expression by qPCR. Further, the adipocyte-conditioned medium was enriched by two types of titanium-related surfaces: Dual Acid-Etching (DAE) and Nano-Hydroxyapatite blasted surfaces (nHA) for up to 24 h. Finally, the endothelial cells (ECs) were exposed in those conditioned media under shear stress mimicking blood flow. Important genes related to angiogenesis were then evaluated by using RT-qPCR and Western blot.

RESULTS

Firstly, the high-adipogenicity model using 3T3-L1 adipocytes was validated presenting an increase in the oxidative stress markers, concomitantly with an increase in intracellular fat droplets, pro-inflammatory-related gene expressions, and also the ECM remodeling, as well as modulating mitogen-activated protein kinases (MAPKs). Additionally, Src was evaluated by Western blot, and its modulation can be related to EC survival signaling.

CONCLUSION

Our study provides an experimental model of high adipogenesis in vitro by establishing a pro-inflammatory environment and intracellular fat droplets. Additionally, the efficacy of this model to evaluate the EC response to titanium-enriched mediums under adipogenicity-related metabolic conditions was analyzed, revealing significant interference with EC performance. Altogether, these data gather valuable findings on understanding the reasons for the higher percentage of implant failures in obese individuals.

Peri-implantitis after 40 years: Evidence, mechanisms, and implications: A mapping review

STATEMENT OF PROBLEM

The high prevalence of peri-implantitis (PI) continues to plague patients and the disease is resistant to present treatment regimens. An analysis of the available research is lacking.

PURPOSE

Given the abundance and diversity of research on the topic of PI, the purpose of this mapping review was to synthesize the literature on the prevention of PI, the histopathology of the disease, the state of present therapeutics, and any emerging treatments.

MATERIAL AND METHODS

An extensive literature search was undertaken by using the electronic databases of PubMed, Web of Science, and Science Direct. The keyword strings were peri-implantitis, dental implant, risk assessment, histopathology, prosthesis design, and treatment. The filters applied were time interval from 2000 to 2002; language, English.

RESULTS

A total of 3635 articles were taken from PubMed, 3686 articles from Web of Science, and 2450 articles from Science Direct. After applying the inclusion and exclusion criteria to the titles and abstracts of selected investigations, 214 studies were retrieved.

CONCLUSIONS

The evidence reflects a concerning incidence of PI, without a predictable treatment protocol. An in-depth patient risk assessment considering risk modification, emphasis on surgical and restorative expertise, and strict recall and maintenance is essential to minimize PI.

Impact of diabetes mellitus on the poor prognosis in patients with osseointegrated dental implants: a meta-analysis of observational studies

This meta-analysis aimed to explore the correlation between diabetes mellitus (DM) and peri-implant diseases in patients with osseointegrated dental implants. Relevant studies were searched in multiple databases from the available date of inception through 26 August 2021. The odds ratios (ORs) were used as the effect indicator for measurement data, and each effect size was given estimates and 95% confidence intervals (CIs). Begg's test was used for publication bias. Twenty-one observational studies with 24,953 participants were selected. No significant association was shown between DM and peri-implant mucositis (OR: 0.739, 95% CI: 0.394-1.383, P = 0.344). The results demonstrated that the risk of peri-implantitis was higher in DM than in non-DM (OR: 1.553, 95% CI: 1.084-2.226, P = 0.016). Smokers had higher risk of peri-implantitis than non-smoking patients (OR: 1.754, 95% CI: 1.620-1.899, P < 0.001). In addition, no significant association was shown between DM and peri-implantitis among non-smokers. The association between periodontal history (OR: 2.538, 95% CI: 0.814-7.921, P = 0.109), poor plaque control (OR: 1.700, 95% CI: 0.334-8.648, P = 0.523) and peri-implantitis was not statistically significant. No publication bias was observed for each outcome. DM increases the risk of poor outcomes in osseointegrated dental implant patients. The findings of the present study further elucidate the need for longitudinal investigations regarding risk variables that affects peri-implant tissues.

Biomineralization inspired 3D printed bioactive glass nanocomposite scaffolds orchestrate diabetic bone regeneration by remodeling micromilieu

Type II diabetes mellitus (TIIDM) remains a challenging clinical issue for both dentists and orthopedists. By virtue of persistent hyperglycemia and altered host metabolism, the pathologic diabetic micromilieu with chronic inflammation, advanced glycation end products accumulation, and attenuated biomineralization severely impairs bone regeneration efficiency. Aiming to "remodel" the pathologic diabetic micromilieu, we 3D-printed bioscaffolds composed of Sr-containing mesoporous bioactive glass nanoparticles (Sr-MBGNs) and gelatin methacrylate (GelMA). Sr-MBGNs act as a biomineralization precursor embedded in the GelMA-simulated extracellular matrix and release Sr, Ca, and Si ions enhancing osteogenic, angiogenic, and immunomodulatory properties. In addition to angiogenic and anti-inflammatory outcomes, this innovative design reveals that the nanocomposites can modulate extracellular matrix reconstruction and simulate biomineralization by activating lysyl oxidase to form healthy enzymatic crosslinked collagen, promoting cell focal adhesion, modulating osteoblast differentiation, and boosting the release of OCN, the noncollagenous proteins (intrafibrillar mineralization dependent), and thus orchestrating osteogenesis through the Kindlin-2/PTH1R/OCN axis. This 3D-printed bioscaffold provides a multifunctional biomineralization-inspired system that remodels the "barren" diabetic microenvironment and sheds light on the new bone regeneration approaches for TIIDM.

Exosome-based bone-targeting drug delivery alleviates impaired osteoblastic bone formation and bone loss in inflammatory bowel diseases

Systematic bone loss is commonly complicated with inflammatory bowel diseases (IBDs) with unclear pathogenesis and uncertain treatment. In experimental colitis mouse models established by dextran sulfate sodium and IL-10 knockout induced with piroxicam, bone mass and quality are significantly decreased. Colitis mice demonstrate a lower bone formation rate and fewer osteoblasts in femur. Bone marrow mesenchymal stem/stromal cells (BMSCs) from colitis mice tend to differentiate into adipocytes rather than osteoblasts. Serum from patients with IBD promotes adipogenesis of human BMSCs. RNA sequencing reveals that colitis downregulates Wnt signaling in BMSCs. For treatment, exosomes with Golgi glycoprotein 1 inserted could carry Wnt agonist 1 and accumulate in bone via intravenous administration. They could alleviate bone loss, promote bone formation, and accelerate fracture healing in colitis mice. Collectively, BMSC commitment in inflammatory microenvironment contributes to lower bone quantity and quality and could be rescued by redirecting differentiation toward osteoblasts through bone-targeted drug delivery.

Harnessing electromagnetic fields to assist bone tissue engineering

Bone tissue engineering (BTE) emerged as one of the exceptional means for bone defects owing to it providing mechanical supports to guide bone tissue regeneration. Great advances have been made to facilitate the success of BTE in regenerating bone within defects. The use of externally applied fields has been regarded as an alternative strategy for BTE. Electromagnetic fields (EMFs), known as a simple and non-invasive therapy, can remotely provide electric and magnetic stimulation to cells and biomaterials, thus applying EMFs to assist BTE would be a promising strategy for bone regeneration. When combined with BTE, EMFs improve cell adhesion to the material surface by promoting protein adsorption. Additionally, EMFs have positive effects on mesenchymal stem cells and show capabilities of pro-angiogenesis and macrophage polarization manipulation. These advantages of EMFs indicate that it is perfectly suitable for representing the adjuvant treatment of BTE. We also summarize studies concerning combinations of EMFs and diverse biomaterial types. The strategy of combining EMFs and BTE receives encouraging outcomes and holds a promising future for effectively treating bone defects.

Poor Metabolic Profile Is an Independent Risk Factor for Recurrence After Hiatal Hernia Repair When Using Tension-Free Mesh

Purpose: The effect of metabolic risk factors on the recurrence rate of hiatal hernia (HH) after the initial repair is still controversial. In this study, we evaluated whether a poor preoperative metabolic profile is a risk factor for the recurrence of a HH after surgery. Methods: Perioperative patient data were obtained from hospital records. A poor metabolic profile was defined as having two or more metabolic conditions such as diabetes, hypertension, hyperlipidemia, or being overweight. The recurrence rates of HH were measured at 6 months, and again at 12 months after surgery. Results: Data were collected from a total of 221 patients. While 87 (39.4%) patients underwent tension-free mesh (TFM) repair, 137 (60.6%) were treated with suture repair. The poor metabolic profile has no effect on the recurrence rates in the suture-repair group. However, patients who underwent TFM repair displayed a significantly higher recurrence rate at the 12-month time point if they had poor metabolic profile, compared to the healthy group (respectively, 20.7% and 3.4%, P < .01). The logistic regression analysis showed that having a poor metabolic profile was an independent risk factor for recurrence after 12 months in the same group (odds ratio: 8.04 confidence interval [CI: 1.2-53.5] P = .03). Conclusion: The poor metabolic profile was found to be responsible for high recurrence rates only in patients who underwent TFM HH repair.

On Peri-Implant Bone Loss Theories: Trying To Piece Together the Jigsaw

This review aims to explore the plausibility of new theories on the etiopathogenesis of marginal bone loss (MBL) and peri-implantitis (PI) and to discuss possible underlying pathogenic mechanisms. The former concept of osteointegration of dental implants can now be conceptualized as a foreign body response histologically characterized by a bony demarcation in combination with chronic inflammation. Different risk factors can provoke additional inflammation and, therefore, pro-inflammatory cytokine release in soft tissues and bone, leading to an overpass of the threshold of peri-implant bone defensive and regenerative capacity. Progressive bone loss observed in MBL and PI is ultimately due to a localized imbalance in the receptor activator of nuclear factor kappaB ligand (RANKL)/Receptor activator of nuclear factor κ B (RANK)/osteoprotegerin (OPG) pathway in favor of increased catabolic activity. The genetic background and the severity and duration of the risk factors could explain differences between individuals in the threshold needed to reach an imbalanced scenario. MBL and PI pathogenesis could be better explained by the "inflammation-immunological balance" theory rather than a solely "infectious disease" conception. The link between the effect of biofilm and other risk factors leading to an imbalanced foreign body response lies in osteoclast differentiation and activation pathways (over)stimulation.

Chitosan@Puerarin hydrogel for accelerated wound healing in diabetic subjects by miR-29ab1 mediated inflammatory axis suppression

Wound healing is one of the major global health concerns in patients with diabetes. Overactivation of pro-inflammatory M1 macrophages is associated with delayed wound healing in diabetes. miR-29ab1 plays a critical role in diabetes-related macrophage inflammation. Hence, inhibition of inflammation and regulation of miR-29 expression have been implicated as new points for skin wound healing. In this study, the traditional Chinese medicine, puerarin, was introduced to construct an injectable and self-healing chitosan@puerarin (C@P) hydrogel. The C@P hydrogel promoted diabetic wound healing and accelerated angiogenesis, which were related to the inhibition of the miR-29 mediated inflammation response. Compared to healthy subjects, miR-29a and miR-29b1 were ectopically increased in the skin wound of the diabetic model, accompanied by upregulated M1-polarization, and elevated levels of IL-1β and TNF-α. Further evaluations by miR-29ab1 knockout mice exhibited superior wound healing and attenuated inflammation. The present results suggested that miR-29ab1 is essential for diabetic wound healing by regulating the inflammatory response. Suppression of miR-29ab1 by the C@P hydrogel has the potential for improving medical approaches for wound repair.

•

A chitosan based hydrogel containing puerarin was constructed for promoting diabetic wound healing.

•

Chitosan@Puerarin hydrogel accelerated skin repair through inhibiting M1-polarization and reducing IL-1β and TNF-α.

•

miR-29 a/b1 was found to be ectopic increased in the skin-wound of diabetic model.

•

miR-29 a/b1 was inhibited by Chitosan@Puerarin in diabetic wound healing.

Metabolic Conditions and Peri-Implantitis

Dental implants to replace lost teeth are a common dentistry practice nowadays. Titanium dental implants display a high success rate and improved safety profile. Nevertheless, there is an increasing peri-implantitis (PI), an inflammatory disease associated with polymicrobial infection that adversely affects the hard and soft tissues around the implant. The present review highlights the contribution of different metabolic conditions to PI. The considerations of both local and systemic metabolic conditions are crucial for planning successful dental implant procedures and during the treatment course of PI. Un- or undertreated PI can lead to permanent jaw bone suffering and dental implant losses. The common mediators of PI are inflammation and oxidative stress, which are also the key mediators of most systemic metabolic disorders. Chronic periodontitis, low-grade tissue inflammation, and increased oxidative stress raise the incidence of PI and the underlying systemic metabolic conditions, such as obesity, diabetes mellitus, or harmful lifestyle factors (cigarette smoking, etc.). Using dental biomaterials with antimicrobial effects could partly solve the problem of pathogenic microbial contamination and local inflammation. With local dentistry considering factors, including oral microbiota and implant quality control, the inclusion of the underlying systemic metabolic conditions into the pre-procedure planning and during the treatment course should improve the chances of successful outcomes.

Impact of local predisposing/precipitating factors and systemic drivers on peri‐implant diseases

BACKGROUND

Strong evidence suggests the infectious nature of peri-implant diseases occurring in susceptible hosts. Epidemiological reports, though, indicate that peri-implantitis is a site-specific entity. Hence, the significance of local factors that may predispose/precipitate plaque accumulation and the impact of systemic drivers that alter the immune response are relevant in the prevention and management of peri-implant disorders.

PURPOSE

The purpose of the present review is to shed light on the significance of local and systemic factors on peri-implant diseases, making special emphasis on the associations with peri-implantitis.

METHODS

The biologic plausibility and supporting evidence aiming at providing a concluding remark were explored in the recent scientific literature for local predisposing/precipitating factors and systemic drivers related to peri-implant diseases.

RESULTS

Local predisposing factors such as soft tissue characteristics, implant position and prosthetic design proved being strongly associated with the occurrence of peri-implant diseases. Hard tissue characteristics, however, failed to demonstrate having a direct association with peri-implant diseases. Robust data points toward the strong link between residual sub-mucosal cement and peri-implant diseases, while limited data suggests the impact of residual sub-mucosal floss and peri-implantitis. Systemic drivers/habits such as hyperglycemia and smoking showed a strong negative impact on peri-implantitis. However, there is insufficient evidence to claim for any link between metabolic syndrome, atherosclerotic cardiovascular disease, and obesity and peri-implant diseases.

CONCLUSION

Local predisposing/precipitating factors and systemic drivers may increase the risk of peri-implant diseases. Therefore, comprehensive anamnesis of the patients, educational/motivational programs and exhaustive prosthetically-driven treatment planning must be fostered aiming at reducing the rate of biological complications in implant dentistry.

The Effect of Laser Micro Grooved Platform Switched Implants and Abutments on Early Crestal Bone Levels and Peri-Implant Soft Tissues Post 1 Year Loading among Diabetic Patients-A Controlled Clinical Trial

Background and Objectives: The study aimed to compare the mean crestal bone level (CBL) and peri-implant soft tissue parameters in laser micro-grooved (LMG) platform switched implants and abutments (I&A) post 1 year of functional loading among non-diabetic and type II diabetic individuals. Materials and methods: Patients with an edentulous site having minimum bone height and width of ≥13 mm and ≥6 mm, respectively, were divided into two groups: (i) Non-diabetic-8 (control) and (ii) diabetic-8 (test). LMG Implants were placed and loaded immediately with a provisional prosthesis. Mean crestal bone level (MCBL) was evaluated radiographically at baseline and at 1 year. Peri-implant attachment level (PIAL) and relative position of the gingival margin (R-PGM) were recorded. Implant stability quotient (ISQ) level and implant survival rate (ISR) were evaluated at 1 year. Results: Early MCBL within the groups 1 year postloading was similar both mesially and distally (control-0.00 to 0.16 mm and 0.00 to 0.17 mm, respectively; test-0.00 to 0.21 mm and 0.00 to 0.22 mm, respectively) with statistical significance (p ≤ 0.003, p ≤ 0.001 and p ≤ 0.001, p ≤ 0.001, respectively). However, intergroup comparison showed no significant difference statistically in the MCBL in 1 year post functional loading. The peri-implant soft tissue parameters showed no significant difference between the groups. ISQ level between both groups did not reveal any significant changes (p ≤ 0.92), and ISR was 100%. Conclusions: LMG Implants resulted in minimal and comparable early crestal bone loss and soft tissue changes post 1 year of functional loading in moderately controlled diabetic and non-diabetic individuals, suggesting that this could be a reliable system for use in systemically compromised individuals.

Dysfunction of macrophages leads to diabetic bone regeneration deficiency

Insufficient bone matrix formation caused by diabetic chronic inflammation can result in bone nonunion, which is perceived as a worldwide epidemic, with a substantial socioeconomic and public health burden. Macrophages in microenvironment orchestrate the inflammation and launch the process of bone remodeling and repair, but aberrant activation of macrophages can drive drastic inflammatory responses during diabetic bone regeneration. In diabetes mellitus, the proliferation of resident macrophages in bone microenvironment is limited, while enhanced myeloid differentiation of hematopoietic stem cells (HSCs) leads to increased and constant monocyte recruitment and thus macrophages shift toward the classic pro-inflammatory phenotype, which leads to the deficiency of bone regeneration. In this review, we systematically summarized the anomalous origin of macrophages under diabetic conditions. Moreover, we evaluated the deficit of pro-regeneration macrophages in the diabetic inflammatory microenvironment. Finally, we further discussed the latest developments on strategies based on targeting macrophages to promote diabetic bone regeneration. Briefly, this review aimed to provide a basis for modulating the biological functions of macrophages to accelerate bone regeneration and rescue diabetic fracture healing in the future.

Preventing Peri-implantitis: The Quest for a Next Generation of Titanium Dental Implants

Titanium and its alloys are frequently the biomaterial of choice for dental implant applications. Although titanium dental implants have been utilized for decades, there are yet unresolved issues pertaining to implant failure. Dental implant failure can arise either through wear and fatigue of the implant itself or peri-implant disease and subsequent host inflammation. In the present report, we provide a comprehensive review of titanium and its alloys in the context of dental implant material, and how surface properties influence the rate of bacterial colonization and peri-implant disease. Details are provided on the various periodontal pathogens implicated in peri-implantitis, their adhesive behavior, and how this relationship is governed by the implant surface properties. Issues of osteointegration and immunomodulation are also discussed in relation to titanium dental implants. Some impediments in the commercial translation for a novel titanium-based dental implant from "bench to bedside" are discussed. Numerous in vitro studies on novel materials, processing techniques, and methodologies performed on dental implants have been highlighted. The present report review that comprehensively compares the in vitro, in vivo, and clinical studies of titanium and its alloys for dental implants.

Strontium-doping promotes bone bonding of titanium implants in osteoporotic microenvironment

Osteoporosis is a major challenge to oral implants, and this study focused on improving the osseointegration ability of titanium (Ti) implants in osteoporosis environment via surface modification, including doping of strontium ion and preparation of nanoscale surface feature. Our previous studies have shown that strontium (Sr) ions can enhance osteogenic activity. Therefore, we aimed to comprehensively evaluate the effect of hydrothermal treatment of Sr-doped titanium implant coating on bone-binding properties in the microenvironment of osteoporosis in this study. We fabricated Sr-doped nanocoating (AHT-Sr) onto the surface of titanium implants via hydrothermal reaction. The rough Sr-doping had good biological functions and could apparently promote osteogenic differentiation of osteoporotic bone marrow mesenchymal stem cells (OVX-BMSCs). Most importantly, AHT-Sr significantly promoted bone integration in the osteoporosis environment. This study provides an effective approach to implant surface modification for better osseointegration in an osteoporotic environment.

Hormone and implant osseointegration: Elaboration of the relationship among function, preclinical, and clinical practice

As clusters of peptides or steroids capable of high-efficiency information transmission, hormones have been substantiated to coordinate metabolism, growth, development, and other physiological processes, especially in bone physiology and repair metabolism. In recent years, the application of hormones for implant osseointegration has become a research hotspot. Herein, we provide a comprehensive overview of the relevant reports on endogenous hormones and their corresponding supplementary preparations to explore the association between hormones and the prognosis of implants. We also discuss the effects and mechanisms of insulin, parathyroid hormone, melatonin, vitamin D, and growth hormone on osseointegration at the molecular and body levels to provide a foothold and guide future research on the systemic conditions that affect the implantation process and expand the relative contraindications of the implant, and the pre-and post-operative precautions. This review shows that systemic hormones can regulate the osseointegration of oral implants through endogenous or exogenous drug-delivery methods.

Survival Rates and Clinical Outcomes of Implant Overdentures in Old and Medically Compromised Patients

Studies on the survival rate of implant overdentures in medically compromised patients are limited because most studies exclude patients with systemic diseases affecting implant prognosis. This retrospective study aimed to evaluate the survival rate and clinical outcomes of dental implants used for overdentures in medically compromised patients. A total of 20 patients (9 men, 11 women; mean age: 67.55 ± 6.84 years, range: 53-81 years) were included. Fourteen patients had more than two systemic diseases, and nine patients had more than three systemic diseases. The mean follow-up period was 39.05 months. Of the 60 implants, 2 failed, resulting in an implant survival rate of 96.6%. No statistical differences were found in implant survival rates according to sex, age, implant diameter, restored arch, or opposing dentition (p > 0.05). A significant difference in mean marginal bone loss (MBL) was noted for restoring the arch (p = 0.022) and opposing dentition (p = 0.036). Implants placed in the mandible and with opposing removable partial dentures and complete dentures showed lower mean MBL. No significant differences in implant MBL were observed in terms of age, sex, or implant diameter (p > 0.05). Favorable clinical outcomes can be expected from implant overdentures using two or four implants in edentulous patients with systemic diseases by ensuring that the patients have a sufficient healing period and regular checkups.

Antiresorptive therapy and dental implant survival: an up to 20-year retrospective cohort study in women

OBJECTIVES

To investigate the effects of antiresorptive treatment on the survival of plateau-root form dental implants.

MATERIALS AND METHODS

Patients undergoing antiresorptive therapy via oral or intravenous administration as well as patients not undergoing antiresorptive therapy and healthy control patients were included in this retrospective cohort study. In total, 1472 implants placed in 631 postmenopausal patients (M: 66.42 ± 9.10 years old), who were followed for a period of up to 20 years (8.78 ± 5.68 years). Kaplan-Meier survival analysis was performed, and univariate and multivariate Cox regression, clustered by each patient, was used to evaluate and study factors affecting the survival of their implants.

RESULTS

Implants placed in patients undergoing oral antiresorptive treatment presented significantly higher survival rates, than implants placed in the osteoporosis/osteopenia control cohort (p value < 0.001), and similar survival rates, when compared to healthy controls (p value = 0.03). Additionally, clustered univariate and multivariate Cox regression analysis also revealed higher implant survival when oral antiresorptive drugs (p value = 0.01 and 0.007, respectively) were used, and lower implant survival in the presence of untreated osteoporosis/osteopenia (p value = 0.002 and 0.005, respectively). Overall, the 20-year implant survival in osteoporotic patients undergoing antiresorptive therapy was 94%. For the failed implants, newly replaced implants in patients under antiresorptive treatment presented a 10-year survival of 89%.

CONCLUSIONS

Long-term plateau-root form implant survival in osteoporotic patients taking oral antiresorptives was similar to a healthy population and significantly higher than the untreated controls.

CLINICAL RELEVANCE

These results suggest that plateau-root form implants provide a robust solution for treating tooth loss in patients, who are undergoing antiresorptive therapy.

Maresin1 Suppresses High-Glucose-Induced Ferroptosis in Osteoblasts via NRF2 Activation in Type 2 Diabetic Osteoporosis

Maresin1 (MaR1) is an endogenous pro-resolving lipid mediator produced from polyunsaturated fatty acids and is believed to have antioxidant and anti-inflammatory properties. The objective of this study was to estimate MaR1′s impact on type 2 diabetic osteoporosis (T2DOP) and its pharmacological mode of action. An in vitro high-glucose model of the osteoblast cell line MC3T3-E1 was constructed and stimulated with MaR1. Type 2 diabetic rats were used to establish in vivo models of calvarial defects and were treated in situ with MaR1. The results revealed that, aside from preventing mortality and promoting the osteogenic capacity of MC3T3-E1 cells, MaR1 increased nuclear factor erythroid-2 related factor 2 (NRF2) signaling as well as the activity of glutathione peroxidase 4 (GPX4) and cystine-glutamate antiporter (SLC7A11) and caused the restraint of ferroptosis under hyperglycemic stimulation. However, the therapeutic impact of MaR1 was significantly diminished due to NRF2-siRNA interference and the ferroptosis activator Erastin. Meanwhile, these results were validated through in vivo experiments. These findings imply that MaR1 activated the NRF2 pathway in vivo and in vitro to alleviate high-glucose-induced ferroptosis greatly. More crucially, MaR1 might effectively reduce the risk of T2DOP.

Science Popularization Education regarding Oral Health-General Health for Nonmedical Undergraduates Applying a SPOC Teaching Model

Objective

To see how effective a blended teaching model based on a small private online course (SPOC) is in a science popularization education course on oral health-general health (OHGH).

Methods

The SPOC blended teaching model was created using an elective classroom course “Oral Prophylaxis and Hygiene” in conjunction with an online learning course called “Preventive Dentistry” from the China University massive open online course (MOOC) for the science popularization education on OHGH. Students' evaluations and teaching efficacy of this science popularization education course were tested using pre- and postcourse questionnaires.

Results

In all, 105 valid questionnaires were returned. Before the course, 95.2% of the students expressed an interest in learning more knowledge on oral disease and OHGH. When compared to those of the precourse, students' knowledge of oral diseases and OHGH was significantly higher (P < 0.0001) and the associated practice after science popularization education was much increased (P < 0.0001 or P = 0.0005), except for root canal therapy (P = 0.3886). The scores of students on the scientific popularization task also improved when compared to those of the previous classroom-only teaching (P < 0.0001). In the postcourse questionnaire, students rated the SPOC teaching mode significantly higher than both online learning and classroom teaching alone (P < 0.0001; P = 0.0117); the SPOC blended teaching was judged as more suitable for science popularization education (P < 0.0001).

Conclusion

The application of the SPOC teaching mode for the science popularization education course on OHGH to nonmedical undergraduates has better teaching outcomes and is more likely to be accepted by college students.

Nanoscale Modification of Titanium Implants Improves Behaviors of Bone Mesenchymal Stem Cells and Osteogenesis In Vivo

The surficial micro/nanotopography and physiochemical properties of titanium implants are essential for osteogenesis. However, these surface characters' influence on stem cell behaviors and osteogenesis is still not fully understood. In this study, titanium implants with different surface roughness, nanostructure, and wettability were fabricated by further nanoscale modification of sandblasted and acid-etched titanium (SLA: sandblasted and acid-etched) by H₂O₂ treatment (hSLAs: H₂O₂ treated SLA). The rat bone mesenchymal stem cells (rBMSCs: rat bone mesenchymal stem cells) are cultured on SLA and hSLA surfaces, and the cell behaviors of attachment, spreading, proliferation, and osteogenic differentiation are further analyzed. Measurements of surface characteristics show hSLA surface is equipped with nanoscale pores on microcavities and appeared to be hydrophilic. In vitro cell studies demonstrated that the hSLA titanium significantly enhances cell response to attachment, spreading, and proliferation. The hSLAs with proper degree of H₂O₂ etching (h1SLA: treating SLA with H₂O₂ for 1 hour) harvest the best improvement of differentiation of rBMSCs. Finally, the osteogenesis in beagle dogs was tested, and the h1SLA implants perform much better bone formation than SLA implants. These results indicate that the nanoscale modification of SLA titanium surface endowing nanostructures, roughness, and wettability could significantly improve the behaviors of bone mesenchymal stem cells and osteogenesis on the scaffold surface. These nanoscale modified SLA titanium scaffolds, fabricated in our study with enhanced cell affinity and osteogenesis, had great potential for implant dentistry.

A Logic-Based Diagnostic and Therapeutic Hydrogel with Multistimuli Responsiveness to Orchestrate Diabetic Bone Regeneration

The regeneration of diabetic bone defects remains challenging as the innate healing process is impaired by glucose fluctuation, reactive oxygen species (ROS), and overexpression of proteinases (such as matrix metalloproteinases, MMPs). A "diagnostic" and therapeutic dual-logic-based hydrogel for diabetic bone regeneration is therefore developed through the design of a double-network hydrogel consisting of phenylboronic-acid-crosslinked poly(vinyl alcohol) and gelatin colloids. It exhibits a "diagnostic" logic to interpret pathological cues (glucose fluctuation, ROS, MMPs) and determines when to release drug in a diabetic microenvironment and a therapeutic logic to program different cargo release to match immune-osteo cascade for better tissue regeneration. The hydrogel is also shown to be mechanically adaptable to the local complexity at the bone defect. Furthermore, the underlying therapeutic mechanism is elucidated, whereby the logic-based cargo release enables the regulation of macrophage polarization by remodeling the mitochondria-related antioxidative system, resulting in enhanced osteogenesis in diabetic bone defects. This study provides critical insight into the design and biological mechanism of dual-logic-based tissue-engineering strategies for diabetic bone regeneration.

Reversal of Osseointegration as a Novel Perspective for the Removal of Failed Dental Implants: A Review of Five Patented Methods

Osseointegration is the basis of successful dental implantology and the foundation of cementless arthroplasty and the osseointegrated percutaneous prosthetic system. Osseointegration has been considered irreversible thus far. However, controlled heating or cooling of dental implants could selectively damage the bone at the bone–implant interface, causing the reversal of osseointegration or “osseodisintegration”. This review compares five methods for implant removal, published as patent documents between 2010 and 2018, which have not yet been discussed in the scientific literature. We describe these methods and evaluate their potential for reversing osseointegration. The five methods have several technical and methodological similarities: all methods include a handpiece, a connecting device for coronal access, and a controlling device, as well as the application of mechanical and/or thermal energy. The proposed method of quantifying the temperature with a sensor as the sole means for regulating the process seems inadequate. A database used in one of the methods, however, allows a more precise correlation between a selected implant and the energy needed for its removal, thus avoiding unnecessary trauma to the patient. A flapless, microinvasive, and bone-conserving approach for removing failed dental implants, facilitating successful reimplantation, would benefit dental implantology. These methods could be adapted to cementless medical implants and osseointegrated percutaneous prosthetics. However, for some of the methods discussed herein, further research may be necessary.

Carbon Nanomaterials Modified Biomimetic Dental Implants for Diabetic Patients

Dental implants are used broadly in dental clinics as the most natural-looking restoration option for replacing missing or highly diseased teeth. However, dental implant failure is a crucial issue for diabetic patients in need of dentition restoration, particularly when a lack of osseointegration and immunoregulatory incompetency occur during the healing phase, resulting in infection and fibrous encapsulation. Bio-inspired or biomimetic materials, which can mimic the characteristics of natural elements, are being investigated for use in the implant industry. This review discusses different biomimetic dental implants in terms of structural changes that enable antibacterial properties, drug delivery, immunomodulation, and osseointegration. We subsequently summarize the modification of dental implants for diabetes patients utilizing carbon nanomaterials, which have been recently found to improve the characteristics of biomimetic dental implants, including through antibacterial and anti-inflammatory capabilities, and by offering drug delivery properties that are essential for the success of dental implants.

Should Quality of Glycemic Control Guide Dental Implant Therapy in Patients with Diabetes? Focus on: Peri-Implant Diseases

BACKGROUND AND AIM

Traditionally patients with metabolic conditions such as diabetes mellitus are considered not suitable candidates for dental implant therapy due to increased risk of infection, impaired bone healing or the potential for vascular complications. Peri-implantitis as the more progressive form of peri-implant disease involves bone loss and estimated to occur in nearly half of all implant cases long-term. Despite extensive research on association of hyperglycemia with dental implants in preclinical and animal models, translational effort to clinical practice is hampered by discrepancies in reported outcome indicators for peri-implantitis in patients with a spectrum of glycemic profiles. This review aims to evaluate clinical evidence for peri-implant disease in metabolically compromised patients and in particular in patients with poorly-controlled diabetes in order to inform clinical management of peri-implant disease.

MATERIALS AND METHODS

A comprehensive literature review was performed utilizing PubMed database and using the key word 'diabetes' combined with "dental implant" or "Periimplantitis" or/and "Preimplant disease".

RESULTS

Clinical studies with follow up more than 1year, systematic review and meta-analysis that evaluated peri-implant disease in diabetic patients in relation to glycemic control were taken into consideration in this review.

CONCLUSION

Studies reported conflicting results regarding the long-term effect of diabetes on peri-implant health regardless of the level glycemic control. Therefore, interpretation of finding and relevance to clinical practise should be considered on individual bases.

Diagnosis of Biofilm-Associated Peri-Implant Disease Using a Fluorescence-Based Approach

Dental implants have become a routine component of daily dental practice and the demand for dental implants is expected to increase significantly in the future. Despite the high success rates of dental implants, failures do occur, resulting in discomfort, rampant destruction of the oral health, or painful and costly surgical replacement of a failed implant. Peri-implant diseases are inflammatory conditions affecting the soft/hard tissues surrounding a functional dental implant. Plenty of experimental evidence indicates that the accumulation of dental plaque at the soft tissue-implant interface and the subsequent local inflammatory response seems to be key in the pathogenesis of the peri-implant mucositis. Such peri-implant-soft tissue interface is less effective than natural teeth in resisting bacterial invasion, enhancing vulnerability to subsequent peri-implant disease. Furthermore, in certain individuals, it will progress to peri-implantitis, resulting in alveolar bone loss and implant failure. Although early diagnosis and accurate identification of risk factors are extremely important to effectively prevent peri-implant diseases, current systematic reviews revealed that a uniform classification and diagnostic methodology for peri-implantitis are lacking. Recent progress on fluorescence-based technology enabled rapid diagnosis of the disease and effective removal of plaques. Here, we briefly review biofilm-associated peri-implant diseases and propose a fluorescence-based approach for more accurate and objective diagnoses. A fluorescence-based diagnosis tool through headlights combined with special-filtered dental loupes may serve as a hands-free solution for both precise diagnosis and effective removal of plaque-biofilms.

PI3K/AKT signaling drives titanium-induced angiogenic stimulus

Although osseointegration and clinical success of titanium (Ti)-implanted materials depend on neovascularization in the reactional peri-implant tissue, very little has been achieved considering the Ti-molecules release on the behavior of endothelial cells. To address this issue, we challenged endothelial cells (HUVECs) with Ti-enriched medium obtained from two types of commercial titanium surfaces [presenting or not dual-acid etching (DAE)] up to 72 h to allow molecular machinery analysis. Our data show that the Ti-enriched medium provokes significant stimulus of angiogenesis-related machinery in endothelial cells by upexpressing VEGFR1, VEGFR2, VEGF, eNOS, and iNOS genes, while the PI3K/Akt signaling pathway was also significantly enhanced. As PI3K/AKT signaling was related to angiogenesis in response to vascular endothelial growth factor (VEGF), we addressed the importance of PI3K/Akt upon Ti-enriched medium responses by concomitantly treating the cells with wortmannin, a well-known PI3K inhibitor. Wortmannin suppressed the angiogenic factors, because VEGF, VEGFR1, and eNOS genes were downregulated in those cells, highlighting the importance of PI3K/AKT signaling on driving angiogenic phenotype and angiogenesis performance within the peri-implant tissue reaction. In conjunction, these data reinforce that titanium-implantable devices modify the metabolism of surrounding cells, such as endothelial cells, probably coupling osteogenesis and angiogenesis processes in peri-implant tissue and then contributing to successfully osseointegration of biomedical titanium-based devices.

Peri-Implant Diseases: Diagnosis, Clinical, Histological, Microbiological Characteristics and Treatment Strategies. A Narrative Review

Since the use of dental implants is continuously increasing, it is imperative for dental practitioners to understand the nature and treatment of peri-implant diseases. The purpose of this manuscript is to comprehensively review peri-implant diseases, their characteristics, as well as their non-surgical and surgical treatment. To that end, the current literature was searched and a narrative review was conducted. It is essential that the case definitions described in the 2017 World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions are used to diagnose and classify peri-implant health, peri-implant mucositis and peri-implantitis. While recent epidemiologic studies on peri-implant diseases exist, there is great heterogeneity in the definition of these conditions. Several risk factors and indicators are reported in the literature, with smoking and diabetes being the most universally accepted. In peri-implant mucositis, non-surgical treatment seems to be sufficient. However, for the treatment of peri-implantitis, a surgical approach, which includes open-flap debridement, apically positioned flap and guided bone regeneration, is considered more appropriate. A great variety of adjuncts to mechanical treatment have been reported with controversial results. Finally, studies comparing results from different peri-implantitis treatments are warranted in randomized controlled clinical trials in order to provide stronger evidence-based approaches.

Advances in Antibacterial Functionalized Coatings on Mg and Its Alloys for Medical Use—A Review

As a revolutionary implant material, magnesium and its alloys have many exciting performances, such as biodegradability, mechanical compatibility, and excellent biosecurity. However, the rapid and uncontrollable degradation rate of magnesium greatly hampers its clinical use. Many efforts have been taken to enhance the corrosion resistance of magnesium. However, it must be noted that improving the corrosion resistance of magnesium will lead to the compromise of its antibacterial abilities, which are attribute and proportional to the alkaline pH during its degradation. Providing antibacterial functionalized coating is one of the best methods for balancing the degradation rate and the antibacterial ability of magnesium. Antibacterial functionalized magnesium is especially well-suited for patients with diabetes and infected wounds. Considering the extremely complex biological environment in the human body and the demands of enhancing corrosion resistance, biocompatibility, osteogenesis, and antibacterial ability, composite coatings with combined properties of different materials may be promising. The aim of this review isto collect and compare recent studies on antibacterial functionalized coatings on magnesium and its alloys. The clinical applications of antibacterial functionalized coatings and their material characteristics, antibacterial abilities, in vitro cytocompatibility, and corrosion resistance are also discussed in detail.

Clinical, histological, and nanomechanical parameters of implants placed in healthy and metabolically compromised patients

OBJECTIVES

To evaluate the clinical outcomes, histological parameters, and bone nanomechanical properties around implants retrieved from healthy and metabolic syndrome (MS) patients.

METHODS

Twenty-four patients with edentulous mandibles (12/condition), received four implants between the mental foramina. An additional implant prototype was placed for retrieval histology. The following clinical outcomes were evaluated: insertion torque (IT), implant stability quotient (ISQ) values at baseline and after 60 days of healing, and implant survival. The prototype was retrieved after the healing and histologically processed for bone morphometric evaluation of bone-to-implant contact (%BIC) and bone area fraction occupancy (%BAFO), and bone nanoindentation to determine the elastic modulus (Em) and hardness (H). Descriptive statistical procedures and survival tests were used to analyze the data.

RESULTS

The final study population was comprised of 10 women and 11 men (∼64 years). A total of 105 implants were placed, 21 retrieved for histology. Implant survival rates were similar between groups (>99 %). Similarly, IT and ISQ analyses showed no significant association with systemic condition (p > 0.216). Histological micrographs depicted similar bone morphology, woven bone, for both conditions. While MS (33 ± 5.3 %) and healthy (39 ± 6.5 %) individuals showed no significant difference for %BIC (p = 0.116), significantly higher %BAFO was observed for healthy (45 ± 4.6 %) relative to MS (30 ± 3.8 %) (p < 0.001). No significant differences on bone nanomechanical properties was observed (p > 0.804).

CONCLUSIONS

Although no significant influence on clinical parameters and bone nanomechanical properties was observed, MS significantly reduced bone formation in the peri-implant area in the short-term.

CLINICAL SIGNIFICANCE

A lower amount of bone formation in the peri-implant area was observed in comparison to healthy patients, although the other short-term clinical outcomes were not significantly different. Considering the escalating prevalence of MS patients in need for implant treatment, it becomes crucial to understand bone-to-implant response to determine the ideal loading time in this population.