Evaluation of the implant stability and the marginal bone level changes during the first three months of dental implant healing process: A prospective clinical study.

Achievement of adequate implant stability is one of the determinants for long-term successful osseointegration. Resonance frequency analysis was developed to monitor implant stability and is now a well-recognized, non-invasive tool for determining the appropriate time for functional loading. However, there have been few studies with continuous evaluation and comparison of implant stability and marginal bone level changes between two different macro designs and clinical situations during the implant healing process. Thus, the purpose of this clinical trial is to evaluate the implant stability and marginal bone level changes of straight and conical implants during the implant healing process. In this prospective clinical trial, 25 participants were randomized to either straight or conical implants. A total of 32 titanium dental implants with a length of 9 mm or 11 mm were installed in the maxilla and the mandible according to the manufacturer's instructions. A resonance frequency analyzer was used to measure the implant stability quotient (ISQ) at the time of implant placement and after 2 weeks, 4 weeks, 6 weeks, 8 weeks, 10 weeks, and 12 weeks of healing. The changes in the peri-implant marginal bone level were evaluated from digital radiographic films taken at the time of implant placement and after 4 weeks, 8 weeks, and 12 weeks of healing. The preliminary results of this study revealed higher ISQ values and better healing tendency for conical implants in comparison with straight implants in the maxilla. Similar ISQ values and healing tendency were observed for straight and conical implants in the mandible. No significant differences in marginal bone loss were found between the straight and conical implants. However, in the mandible, slightly more marginal bone loss was found with the conical implants than straight implants after 12 weeks of healing. In conclusion, ISQ healing tendency and marginal bone loss are influenced by implant macro-design and jaw regions. Straight implants revealed similar ISQ healing tendency and marginal bone loss in both the mandible and maxilla. Conical implants were confirmed more beneficial for maintenance of implant stability and marginal bone level in the maxilla.

Adipose-derived Stem Cells Attenuates Diabetic Osteoarthritis via Inhibition of Glycation-mediated Inflammatory Cascade.

Diabetes mellitus (DM) is well-known to exert complications such as retinopathy, cardiomyopathy and neuropathy. However, in recent years, an elevated osteoarthritis (OA) complaints among diabetics have been observed, portending the risk of diabetic OA. Since formation of advanced glycation end products (AGE) is believed to be the etiology of various diseases under hyperglycemic conditions, we firstly established that streptozotocin-induced DM could potentiate the development of OA in C57BL/6J mouse model, and further explored the intra-articularly administered adipose-derived stem cell (ADSC) therapy focusing on underlying AGE-associated mechanism. Our results demonstrated that hyperglycemic mice exhibited OA-like structural impairments including a proteoglycan loss and articular cartilage fibrillations in knee joint. Highly expressed levels of carboxymethyl lysine (CML), an AGE and their receptors (RAGE), which are hallmarks of hyperglycemic microenvironment were manifested. The elevated oxidative stress in diabetic OA knee-joint was revealed through increased levels of malondialdehyde (MDA). Further, oxidative stress-activated nuclear factor kappa B (NF-κB), the marker of proinflammatory signalling pathway was also accrued; and levels of matrix metalloproteinase-1 and 13 were upregulated. However, ADSC treatment attenuated all OA-like changes by 4 weeks, and dampened levels of CML, RAGE, MDA, NF-κB, MMP-1 and 13. These results suggest that during repair and regeneration, ADSCs inhibited glycation-mediated inflammatory cascade and rejuvenated cartilaginous tissue, thereby promoting knee-joint integrity in diabetic milieu.

Correlation between Diabetes Mellitus and Knee Osteoarthritis: A Dry-To-Wet Lab Approach.

Recent years have witnessed an increased prevalence of knee osteoarthritis (KOA) among diabetes mellitus (DM) patients-conditions which might share common risk factors such as obesity and advanced aging. Therefore, we conducted dry-to-wet lab research approaches to assess the correlation of type 1 DM (T1DM) and type 2 DM (T2DM) with KOA among all age and genders of Taiwanese population. The strength of association (odds ratio: OR) was analyzed using a phenome-wide association study portal. Populations of 37,353 T1DM and 1,218,254 T2DM were included. We observed a significant association of KOA with T1DM (OR: 1.40 (1.33⁻1.47), p< 0.0001) and T2DM (OR: 2.75 (2.72⁻2.78), p< 0.0001). The association between T1DM and KOA among the obese (OR: 0.99 (0.54⁻1.67), p = 0.0477) was insignificant compared to the non-obese (OR: 1.40 (1.33⁻1.48), p < 0.0001). Interestingly, a higher association between T2DM and KOA among non-obese persons (OR: 2.75, (2.72⁻2.79), p < 0.0001) compared to the obese (OR: 1.71 (1.55⁻1.89), p < 0.0001) was noted. Further, histopathologic and Western blot studies of diabetic mice knee joints revealed enhanced carboxymethyl lysine (advanced glycation end product), matrix metalloproteinase-1, and reduced cartilage-specific proteins, including type II collagen (Col II), SOX9, and aggrecan (AGN), indicating deteriorated articular cartilage and proteoglycans. Results indicate that DM is strongly associated with KOA, and obesity may not be a confounding factor.

NSC 95397 Suppresses Proliferation and Induces Apoptosis in Colon Cancer Cells through MKP-1 and the ERK1/2 Pathway.

NSC 95397, a quinone-based small molecule compound, has been identified as an inhibitor for dual-specificity phosphatases, including mitogen-activated protein kinase phosphatase-1 (MKP-1). MKP-1 is known to inactivate mitogen-activated protein kinases by dephosphorylating both of their threonine and tyrosine residues. Moreover, owing to their participation in tumorigenesis and drug resistance in colon cancer cells, MKP-1 is an attractive therapeutic target for colon cancer treatment. We therefore investigated the inhibitory activity of NSC 95397 against three colon cancer cell lines including SW480, SW620, and DLD-1, and their underlying mechanisms. The results demonstrated that NSC 95397 reduced cell viability and anchorage-independent growth of all the three colon cancer cell lines through inhibited proliferation and induced apoptosis via regulating cell-cycle-related proteins, including p21, cyclin-dependent kinases, and caspases. Besides, by using mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibitor U0126, we provided mechanistic evidence that the antineoplastic effects of NSC 95397 were achieved via inhibiting MKP-1 activity followed by ERK1/2 phosphorylation. Conclusively, our results indicated that NSC 95397 might serve as an effective therapeutic intervention for colon cancer through regulating MKP-1 and ERK1/2 pathway.

Combating Osteoarthritis through Stem Cell Therapies by Rejuvenating Cartilage: A Review.

Knee osteoarthritis (OA) is a chronic degenerative disorder which could be distinguished by erosion of articular cartilage, pain, stiffness, and crepitus. Not only aging-associated alterations but also the metabolic factors such as hyperglycemia, dyslipidemia, and obesity affect articular tissues and may initiate or exacerbate the OA. The poor self-healing ability of articular cartilage due to limited regeneration in chondrocytes further adversely affects the osteoarthritic microenvironment. Traditional and current surgical treatment procedures for OA are limited and incapable to reverse the damage of articular cartilage. To overcome these limitations, cell-based therapies are currently being employed to repair and regenerate the structure and function of articular tissues. These therapies not only depend upon source and type of stem cells but also on environmental conditions, growth factors, and chemical and mechanical stimuli. Recently, the pluripotent and various multipotent mesenchymal stem cells have been employed for OA therapy, due to their differentiation potential towards chondrogenic lineage. Additionally, the stem cells have also been supplemented with growth factors to achieve higher healing response in osteoarthritic cartilage. In this review, we summarized the current status of stem cell therapies in OA pathophysiology and also highlighted the potential areas of further research needed in regenerative medicine.

Dental Implant Surrounding Marginal Bone Level Evaluation: Platform Switching versus Platform Matching-One-Year Retrospective Study.

The benefits and feasibility of platform switching have been discussed in several studies, reporting lesser crestal bone loss in platform-switched implants than in platform-matched implants. Objective. The aim of the present study was to observe the changes in vertical and horizontal marginal bone levels in platform-switched and platform-matched dental implants. Materials and Methods. 51 patients received 60 dental implants in the present study over a 1-year period. Measurement was performed between the implant shoulder and the most apical and horizontal marginal defect by periapical radiographs to examine the changes of peri-implant alveolar bone before and 12 months after prosthodontic restoration delivery. Results. These marginal bone measurements showed a bone gain of 0.23 ± 0.58 mm in the vertical gap and 0.22 ± 0.53 mm in the horizontal gap of platform matching, while in platform switching a bone gain of 0.93 ± 1 mm (P < 0.05) in the vertical gap and 0.50 ± 0.56 mm in the horizontal gap was found. The average vertical gap reduction from the baseline until 12 months was 0.92 ± 1.11 mm in platform switching and 0.29 ± 0.85 mm in platform matching (P < 0.05). Conclusions. Within the limitations of the present study, platform switching seemed to be more effective for a better peri-implant alveolar bone vertical and horizontal gap reduction at 1 year.

Enhancement of Osteoblastic-Like Cell Activity by Glow Discharge Plasma Surface Modified Hydroxyapatite/ß-Tricalcium Phosphate Bone Substitute.

Glow discharge plasma (GDP) treatments of biomaterials, such as hydroxyapatite/ß-tricalcium phosphate (HA/ß-TCP) composites, produce surfaces with fewer contaminants and may facilitate cell attachment and enhance bone regeneration. Thus, in this study we used argon glow discharge plasma (Ar-GDP) treatments to modify HA/ß-TCP particle surfaces and investigated the physical and chemical properties of the resulting particles (HA/ß-TCP + Ar-GDP). The HA/ß-TCP particles were treated with GDP for 15 min in argon gas at room temperature under the following conditions: power: 80 W; frequency: 13.56 MHz; pressure: 100 mTorr. Scanning electron microscope (SEM) observations showed similar rough surfaces of HA/ß-TCP + Ar-GDP HA/ß-TCP particles, and energy dispersive spectrometry analyses showed that HA/ß-TCP surfaces had more contaminants than HA/ß-TCP + Ar-GDP surfaces. Ca/P mole ratios in HA/ß-TCP and HA/ß-TCP + Ar-GDP were 1.34 and 1.58, respectively. Both biomaterials presented maximal intensities of X-ray diffraction patterns at 27° with 600 a.u. At 25° and 40°, HA/ß-TCP + Ar-GDP and HA/ß-TCP particles had peaks of 200 a.u., which are similar to XRD intensities of human bone. In subsequent comparisons, MG-63 cell viability and differentiation into osteoblast-like cells were assessed on HA/ß-TCP and HA/ß-TCP + Ar-GDP surfaces, and Ar-GDP treatments led to improved cell growth and alkaline phosphatase activities. The present data indicate that GDP surface treatment modified HA/ß-TCP surfaces by eliminating contaminants, and the resulting graft material enhanced bone regeneration.

Surface analysis of titanium biological modification with glow discharge.

BACKGROUND: Glow discharge plasma (GDP) technology has been used to graft various proteins to the titanium surface, including albumin, type I collagen, but without fibronectin. PURPOSE: The aim of this study was to evaluate and analyze the physical properties of fibronectin-grafted titanium surfaces after GDP treatment. MATERIALS AND METHODS: Grade II titanium discs after cleaning and autoclaving were considered as original specimens, thus divided into four groups. The groups were different upon two treatments (GDP only and fibronectin grafting after GDP) and two storage temperature (4°C and 25°C). The implant surface morphology was characterized by scanning electron microscopy (SEM), roughness measurement, and wettability evaluation. The concentration relationship of fibronectin was by fluorescein isothiocyanate (FITC) labeling. RESULTS: SEM images showed that regular planar texture revealed on the surface of GDP-treated group, and irregular-folding protein was found on the fibronectin-grafted discs. Fibronectin-grafted groups had higher hydrophilicity and greater surface roughness than GDP-treated specimens. The storage temperature did not make obvious difference on the surface topography, wettability, and roughness. The number of fibronectin dots on the titanium surface labeling by FITC had positive relationship with the concentration of fibronectin solution used. CONCLUSIONS: Biologically modified titanium surface is more hydrophilic and rougher than GDP-treated ones. GDP treatment combined with fibronectin grafting increased the surface hydrophilicity and surface roughness of titanium discs, which may attribute to the affinity of cell adhesion, migration, proliferation, and differentiation.

In vivo evaluation of resorbable bone graft substitutes in beagles: histological properties.

Calcium phosphate cement (CPC) is a promising material for use in minimally invasive surgery for bone defect repairs due to its bone-like apatitic final setting product, biocompatibility, bioactivity, self-setting characteristics, low setting temperature, adequate stiffness, and easy shaping into complicated geometrics. However, even though CPC is stable in vivo, the resorption rate of this bone cement is very slow and its long setting time poses difficulties for clinical use. Calcium sulfate dehydrate (CSD) has been used as a filler material and/or as a replacement for cancellous bone grafts due to its biocompatibility. However, it is resorbed too quickly to be optimal for bone regeneration. This study examines the invivo response of a hydroxyapatite (HA), [apatitic phase (AP)]/calcium sulfate (CSD) composite using different ratios in the mandibular premolar sockets of beagles. The HA (AP)/CSD composite materials were prepared in the ratios of 30/70, 50/50, and 70/30 and then implanted into the mandibular premolar sockets for terms of 5 and 10 weeks. The control socket was left empty. The study shows better new bone morphology and more new bone area in the histological and the histomorphometric study of the HA (AP)/CSD in the 50/50 ratio.

Localized vertical maxillary ridge augmentation using symphyseal bone cores: a technique and case report.

Vertical augmentation of the alveolar ridge is intended to restore resorbed alveolar ridges. This procedure is important for the placement of dental implants in a favorable position and also to enhance restoration esthetics. This article presents an approach for vertical ridge augmentation in the anterior maxilla utilizing symphyseal bone cores. A patient presented with 2 localized bony defects around the maxillary lateral incisors. Following extraction of these teeth, vertical bone defects of 7 mm on the right and 6 mm on the left were observed in relation to the cementoenamel junction of the adjacent teeth. Two bone cores were harvested from the mandibular symphysis using a trephine. These bone cores were tapped into 2 predrilled osteotomy sites with corresponding diameters until stabilization was achieved. The 2 sites were grafted with demineralized freeze-dried bone allograft and a titanium-reinforced expanded polytetrafluoroethylene membrane. After 5 months, the membranes were removed and vertical ridge augmentation of 5 mm on the right and 4 mm on the left was observed. The width of the ridge was increased as well. Two implants were placed in favorable positions, restored after 6 months, and followed successfully for 1 year after loading. This technique represents a viable approach for augmentation of deficient alveolar ridges prior to the placement of dental implants.

One-stage maxillary sinus elevation using a bone core containing a preosseointegrated implant from the mandibular symphysis.

This report presents a novel surgical approach of a one-stage maxillary sinus elevation using a bone core containing a preosseointegrated implant harvested from the mandibular symphysis. As a result, the elevation of the floor of the maxillary sinus and the placement of the implant were achieved at the same time, and the required healing time was significantly reduced. Three months after placement of the implant in the symphysis, a bone core containing the implant was retrieved using a trephine. The bone core was placed in the resorbed posterior maxillary ridge, thereby elevating the maxillary sinus floor. The bone core containing the implant was allowed to heal for 5 months, after which the implant was restored and followed up for 30 months. This technique represents a surgical modification intended to avoid the conventional two-step sinus elevation surgery in which the surgical procedure of graft placement is followed by surgical implant placement. This approach requires significantly reduced healing time and provides an increased bone quality around the implant, which is of clinical importance, particularly in the posterior maxilla.