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Molecules (Basel, Switzerland) May 2021After tooth loss, bone resorption is irreversible, leaving the area without adequate bone volume for successful implant treatment. Bone grafting is the only solution to... (Review)
Review
After tooth loss, bone resorption is irreversible, leaving the area without adequate bone volume for successful implant treatment. Bone grafting is the only solution to reverse dental bone loss and is a well-accepted procedure required in one in every four dental implants. Research and development in materials, design and fabrication technologies have expanded over the years to achieve successful and long-lasting dental implants for tooth substitution. This review will critically present the various dental bone graft and substitute materials that have been used to achieve a successful dental implant. The article also reviews the properties of dental bone grafts and various dental bone substitutes that have been studied or are currently available commercially. The various classifications of bone grafts and substitutes, including natural and synthetic materials, are critically presented, and available commercial products in each category are discussed. Different bone substitute materials, including metals, ceramics, polymers, or their combinations, and their chemical, physical, and biocompatibility properties are explored. Limitations of the available materials are presented, and areas which require further research and development are highlighted. Tissue engineering hybrid constructions with enhanced bone regeneration ability, such as cell-based or growth factor-based bone substitutes, are discussed as an emerging area of development.
Topics: Bone Substitutes; Bone Transplantation; Cell Survival; Dentistry; Humans; Intercellular Signaling Peptides and Proteins; Osteogenesis
PubMed: 34070157
DOI: 10.3390/molecules26103007 -
International Journal of Implant... Apr 2022The aim of this study was to systematically review the available evidence to evaluate the efficacy of vitamin D supplementation or vitamin D depletion on the... (Review)
Review
PURPOSE
The aim of this study was to systematically review the available evidence to evaluate the efficacy of vitamin D supplementation or vitamin D depletion on the osseointegration of implants in animals and humans.
METHODS
The focus questions addressed were "Do vitamin D deficient subjects treated with (dental) implants have an inferior osseointegration than subjects with adequate serum vitamin D level?" and "Do vitamin D supplemented subjects treated with (dental) implants have a superior osseointegration than subjects with adequate serum vitamin D level?" Humans and animals were considered as subjects in this study. Databases were searched from 1969 up to and including March 2021 using different combination of the following terms: "implant", "bone to implant contact", "vitamin D" and "osseointegration". Letters to the editor, historic reviews, commentaries and articles published in languages other than English and German were excluded. The pattern of the present systematic review was customize to primarily summarize the pertinent data.
RESULTS
Thirteen experimental studies with animals as subject, two clinical studies and three case reports, with humans as subjects, were included. The amount of inserted titanium implants ranged between 24 and 1740. Results from three animal studies showed that vitamin D deficiency has a negative effect on new bone formation and/or bone to implant contact (BIC). Eight animal studies showed that vitamin D supplementation has a enhancing effect on BIC and/or new bone formation around implants. Furthermore, enhancing the impact of vitamin D supplementation on the osseointegration of implants in subjects with diabetes mellitus, osteoporosis and chronic kidney disease (CKD) were assessed. Studies and case reports involving human subjects showed that patients with a low serum vitamin D level have a higher tendency to exhibit an early dental implant failure. When supplemented with vitamin D the osseointegration was successful in the case reports and a beneficial impact on the changes in the bone level during the osseointegration were determined.
CONCLUSIONS
Vitamin D deficiency seems to have a negative effect on the osseointegration of implants in animals. The supplementation of vitamin D appears to improve the osseointegration in animals with systemic diseases, such as vitamin D deficiency, diabetes mellitus, osteoporosis, and CKD. Slight evidence supports the hypothesis that humans similarly benefit from vitamin D supplementation in terms of osseointegration. Further investigation is required to maintain these assumptions.
Topics: Animals; Dental Implantation, Endosseous; Dental Implants; Diabetes Mellitus; Humans; Osseointegration; Osteoporosis; Renal Insufficiency, Chronic; Vitamin D; Vitamin D Deficiency; Vitamins
PubMed: 35403929
DOI: 10.1186/s40729-022-00414-6 -
Nature Communications Nov 2021Clinically, it is difficult to endow implants with excellent osteogenic ability and antibacterial activity simultaneously. Herein, the self-activating implants modified...
Clinically, it is difficult to endow implants with excellent osteogenic ability and antibacterial activity simultaneously. Herein, the self-activating implants modified with hydroxyapatite (HA)/MoS coating are designed to prevent Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) infections and accelerate bone regeneration simultaneously. The electron transfer between bacteria and HA/MoS is triggered when bacteria contacted with the material. RNA sequencing data reveals that the expression level of anaerobic respiration-related genes is up-regulated and the expression level of aerobic respiration-related genes is down-regulated when bacteria adhere to the implants. HA/MoS presents a highly effective antibacterial efficacy against both S. aureus and E. coli because of bacterial respiration-activated metabolic pathway changes. Meanwhile, this coating promotes the osteoblastic differentiation of mesenchymal stem cells by altering the potentials of cell membrane and mitochondrial membrane. The proposed strategy exhibits great potential to endow implants with self-activating anti-infection performance and osteogenic ability simultaneously.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Bone Regeneration; Bone and Bones; Cell Differentiation; Cell Membrane; Cell Proliferation; Cell Respiration; Communicable Diseases; Disease Models, Animal; Drug Implants; Durapatite; Electron Transport; Escherichia coli; Escherichia coli Infections; Male; Mesenchymal Stem Cells; Osteogenesis; Rats; Rats, Sprague-Dawley; Staphylococcal Infections; Staphylococcus aureus; Up-Regulation
PubMed: 34824260
DOI: 10.1038/s41467-021-27217-4 -
Drugs & Aging Jun 2020Bimatoprost implant (Durysta™), developed by Allergan, is a sustained-release drug delivery system containing bimatoprost, a prostaglandin analogue with ocular... (Review)
Review
Bimatoprost implant (Durysta™), developed by Allergan, is a sustained-release drug delivery system containing bimatoprost, a prostaglandin analogue with ocular hypotensive activity. The implant, administered intracamerally, involves the use of a biodegradable, solid polymer drug delivery system for slow, sustained drug release, designed to lower intraocular pressure (IOP) over a 4- to 6-months period. In March 2020, bimatoprost implant received its first approval, in the USA, for use to reduce IOP in patients with open angle glaucoma (OAG) or ocular hypertension (OHT). Allergan's clinical development programme for bimatoprost implant is ongoing. This article summarizes the milestones in the development of bimatoprost implant leading to this first approval for use in the reduction of IOP in patients with OAG or OHT.
Topics: Bimatoprost; Drug Approval; Glaucoma, Open-Angle; Humans; Intraocular Pressure; Ocular Hypertension; Prostheses and Implants
PubMed: 32447639
DOI: 10.1007/s40266-020-00769-8 -
Taiwan Journal of Ophthalmology 2019Diabetic macular edema (DME) is a chronic condition with a multifactorial pathogenesis. Vascular endothelial growth factor (VEGF) and several inflammatory mediators are... (Review)
Review
Diabetic macular edema (DME) is a chronic condition with a multifactorial pathogenesis. Vascular endothelial growth factor (VEGF) and several inflammatory mediators are upregulated in eyes with DME. VEGF inhibitors and corticosteroids have all been used successfully in the management of DME. Currently available corticosteroids include triamcinolone acetonide (TA), the dexamethasone (DEX) intravitreal implant, and the fluocinolone acetonide (FA) intravitreal implant. The response to treatment can vary substantially with each treatment modality. Some cases of DME are VEGF driven, and in others, inflammation plays a key role. Chronicity appears to favor corticosteroid treatment. There are no clear guidelines to guide switching from an anti-VEGF to a corticosteroid. Combination therapy of an anti-VEGF drug and a corticosteroid does not appear to provide additional benefit over monotherapy with either drug. The main advantage of corticosteroids over VEGF inhibitors is their longer duration of action. Vitrectomy does not affect the pharmacokinetics of the corticosteroid implants. Common adverse events of corticosteroids include cataract formation, cataract progression, and ocular hypertension. TA may cause a sterile endophthalmitis and pseudoendophthalmitis. Migration of the intravitreal DEX and FA implants into the anterior chamber can be problematic. Because of their less favorable safety profile, corticosteroids are generally used as a second-line treatment for DME. Advantages of using an intravitreal corticosteroid implant include the reduction of treatment burden and predictable pharmacokinetics even in vitrectomized eyes. Pseudophakic eyes, previously vitrectomized eyes and eyes with long-standing DME, particularly of patients who have difficulty in maintaining a monthly appointment, may benefit from primary treatment with a corticosteroid intravitreal implant.
PubMed: 31942428
DOI: 10.4103/tjo.tjo_68_19 -
Journal of General Internal Medicine Jan 2022Breast implant surgery for cosmetic or reconstructive purposes is becoming increasingly common. While the devices used are regulated and approved by the US Food and Drug...
Breast implant surgery for cosmetic or reconstructive purposes is becoming increasingly common. While the devices used are regulated and approved by the US Food and Drug Administration, all patients with breast implants require continued follow-up. Many patients will seek this care from their primary care providers, especially when follow-up with their plastic surgeon is difficult. It is vital that treating clinicians are knowledgeable about the history of breast implants, routine screening guidelines, and the recent breast implant "hot topics"-breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), connective tissue disease, and breast implant illness. This paper will provide the necessary information for primary care providers to appropriately counsel patients with breast implants to maintain not only their trust, but also their health.
Topics: Breast Implantation; Breast Implants; Breast Neoplasms; Female; Humans; Lymphoma, Large-Cell, Anaplastic
PubMed: 34027608
DOI: 10.1007/s11606-021-06899-y -
Nature Communications May 2021Polymeric drug carriers are widely used for providing temporal and/or spatial control of drug delivery, with corticosteroids being one class of drugs that have...
Polymeric drug carriers are widely used for providing temporal and/or spatial control of drug delivery, with corticosteroids being one class of drugs that have benefitted from their use for the treatment of inflammatory-mediated conditions. However, these polymer-based systems often have limited drug-loading capacity, suboptimal release kinetics, and/or promote adverse inflammatory responses. This manuscript investigates and describes a strategy for achieving controlled delivery of corticosteroids, based on a discovery that low molecular weight corticosteroid dimers can be processed into drug delivery implant materials using a broad range of established fabrication methods, without the use of polymers or excipients. These implants undergo surface erosion, achieving tightly controlled and reproducible drug release kinetics in vitro. As an example, when used as ocular implants in rats, a dexamethasone dimer implant is shown to effectively inhibit inflammation induced by lipopolysaccharide. In a rabbit model, dexamethasone dimer intravitreal implants demonstrate predictable pharmacokinetics and significantly extend drug release duration and efficacy (>6 months) compared to a leading commercial polymeric dexamethasone-releasing implant.
Topics: Adrenal Cortex Hormones; Animals; Cells, Cultured; Delayed-Action Preparations; Dexamethasone; Dimerization; Disease Models, Animal; Drug Delivery Systems; Drug Implants; Drug Liberation; Polymers; Rabbits; Rats; Uveitis
PubMed: 34001908
DOI: 10.1038/s41467-021-23232-7 -
Journal of Ocular Pharmacology and... May 2020Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that degrade extracellular matrix (ECM) components such as collagen and have important roles in... (Review)
Review
Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that degrade extracellular matrix (ECM) components such as collagen and have important roles in multiple biological processes, including development and tissue remodeling, both in health and disease. The activity of MMPs is influenced by the expression of MMPs and tissue inhibitors of metalloproteinase (TIMPs). In the eye, MMP-mediated ECM turnover in the juxtacanalicular region of the trabecular meshwork (TM) reduces outflow resistance in the conventional outflow pathway and helps maintain intraocular pressure (IOP) homeostasis. An imbalance in the MMP/TIMP ratio may be involved in the elevated IOP often associated with glaucoma. The prostaglandin analog/prostamide (PGA) class of topical ocular hypotensive medications used in glaucoma treatment reduces IOP by increasing outflow through both conventional and unconventional (uveoscleral) outflow pathways. Evidence from and studies using animal models and anterior segment explant and cell cultures indicates that the mechanism of IOP lowering by PGAs involves increased MMP expression in the TM and ciliary body, leading to tissue remodeling that enhances conventional and unconventional outflow. PGA effects on MMP expression are dependent on the identity and concentration of the PGA. An intracameral sustained-release PGA implant (Bimatoprost SR) in development for glaucoma treatment can reduce IOP for many months after expected intraocular drug bioavailability. We hypothesize that the higher concentrations of bimatoprost achieved in ocular outflow tissues with the implant produce greater MMP upregulation and more extensive, sustained MMP-mediated target tissue remodeling, providing an extended duration of effect.
Topics: Administration, Topical; Animals; Antihypertensive Agents; Bimatoprost; Ciliary Body; Collagen; Drug Implants; Extracellular Matrix; Glaucoma; Homeostasis; Humans; Intraocular Pressure; Matrix Metalloproteinases; Models, Animal; Prostaglandins, Synthetic; Tissue Inhibitor of Metalloproteinases; Trabecular Meshwork
PubMed: 32233938
DOI: 10.1089/jop.2019.0146 -
Materials (Basel, Switzerland) Jul 2023Controlled drug delivery in the oral cavity poses challenges such as bacterial contamination, saliva dilution, and inactivation by salivary enzymes upon ingestion.... (Review)
Review
Controlled drug delivery in the oral cavity poses challenges such as bacterial contamination, saliva dilution, and inactivation by salivary enzymes upon ingestion. Microneedles offer a location-specific, minimally invasive, and retentive approach. Hydrogel-forming microneedles (HFMs) have emerged for dental diagnostics and therapeutics. HFMs penetrate the stratum corneum, undergo swelling upon contact, secure attachment, and enable sustained transdermal or transmucosal drug delivery. Commonly employed polymers such as polyvinyl alcohol (PVA) and polyvinyl pyrrolidone are crosslinked with tartaric acid or its derivatives while incorporating therapeutic agents. Microneedle patches provide suture-free and painless drug delivery to keratinized or non-keratinized mucosa, facilitating site-specific treatment and patient compliance. This review comprehensively discusses HFMs' applications in dentistry such as local anesthesia, oral ulcer management, periodontal treatment, etc., encompassing animal experiments, clinical trials, and their fundamental impact and limitations, for example, restricted drug carrying capacity and, until now, a low number of dental clinical trial reports. The review explores the advantages and future perspectives of HFMs for oral drug delivery.
PubMed: 37445119
DOI: 10.3390/ma16134805