Clinical and microbiologic investigation of an expedited peri-implantitis dog model: an animal study.

BACKGROUND: Animal studies are pivotal in allowing experimentation to identify efficacious treatment protocols for resolution of peri-implantitis. The purpose of this investigation was to characterize an expedited dog peri-implantitis model clinically, radiographically, and microbiologically. METHODS: Eight hound dogs underwent extractions (week 0) and implant (3.3 × 8.5 mm) placement with simultaneous surgical defect creation and ligature placement for induction of peri-implantitis (week 10). Ligatures were replaced at 6 weeks (week 16) and removed after 9 weeks (week 19) when supporting bone loss involved approximately 50% of the peri-implant bone. Microbial samples from the defects and healthy control implant sites collected at week 19 were analyzed utilizing a microarray. Clinical measures of inflammation were obtained and radiographic bone loss was measured from periapical radiographs. Radiographic depth and width measurements of bony defect were repeated at weeks 10 (baseline), 16, and 19. Canonical analysis of principal coordinates was used to visualize overall differences in microbial abundance between peri-implantitis and healthy implants. RESULTS: This accelerated disease protocol led to intrabony defect creation with a mean depth and width of 4.3 mm and 3.5 mm, respectively after 9 weeks of ligature placement. Microbial identification revealed 59 total bacteria in peri-implant sites, 21 of which were only present in peri-implant sites as compared to healthy controls. Overall microbial beta diversity (microbial between-sample compositional diversity) differed between peri-implantitis and healthy implants (p = 0.009). CONCLUSIONS: Within the limitations of this study, this protocol led to expedited generation of peri-implant defects with a microbial profile indicative of a shift to disease and defect patterns conducive to regenerative treatment. However, the possibility of potential spontaneous resolution of lesions due to the lack of a chronicity interval as compared to chronic disease models need to be further clarified and considered during preclinical peri-implantitis model selection.

Nasal Deviation in Patients With Asymmetric Mandibular Prognathism.

PURPOSE: This study was aimed to evaluate the nasal deviation in patients with asymmetric mandibular prognathism. MATERIALS AND METHODS: Thirty-five patients with skeletal class III malocclusion were included in the study. Significant mandibular asymmetry of >4 mm menton deviation in three-dimensional (3D) reformatted cone beam computed tomography images was defined as asymmetry group (n = 20). Patients without mandibular asymmetry served as control group (n = 15). The mandibular asymmetry was evaluated pre- and postoperatively. RESULTS: Nasal tip was significantly shifted to the deviated side of the mandible (short side) in the asymmetry group, as compared to the control group (1.5 ±â€Š0.9 degree, P < 0.01). Alar base angle (ABA) was significantly narrower in nondeviated side (long side) than in the deviated side in asymmetry group. However, control group showed no bilateral difference in ABA. Correction of deviated mandibular prognathism by isolated mandibular surgery resulted in change in the ABA but not the columella base position or nasal asymmetry. ABA on nondeviated side significantly decreased in proportion to the amount of transverse menton movement by surgery (r = -0.560, P < 0.01). CONCLUSION: Our results showed that mandibular chin deviation was accompanied by nasal deviation. Isolated mandibular surgery can potentially influence the alar base position on the contralateral side of deviation but not the nasal tip asymmetry. Therefore, clinicians should inform patients preoperatively of the fundamental limitation of mandibular surgery in cases with preexisting nasal asymmetry.

Characterization and antimicrobial efficacy of Portland cement impregnated with silver nanoparticles.

PURPOSE: This study investigated the effects of silver nanoparticle (SN) loading into hydraulic calcium silicate-based Portland cement on its mechanical, antibacterial behavior and biocompatibility as a novel dental bone substitute. MATERIALS AND METHODS: Chemically reduced colloidal SN were combined with Portland cement (PC) by the concentrations of 0 (control), 1.0, 3.0, and 5.0 wt%. The physico-mechanical properties of silver-Portland cement nanocomposites (SPNC) were investigated through X-ray diffraction (XRD), setting time, compressive strength, solubility, and silver ion elution. Antimicrobial properties of SPNC were tested by agar diffusion against Streptococcus mutans and Streptococcus sobrinus. Cytotoxic evaluation for human gingival fibroblast (HGF) was performed by MTS assay. RESULTS: XRD certified that SN was successfully impregnated in PC. SPNC at above 3.0 wt% significantly reduced both initial and final setting times compared to control PC. No statistical differences of the compressive strength values were detected after SN loadings, and solubility rates of SPNC were below 3.0%, which are acceptable by ADA guidelines. Ag ion elutions from SPNC were confirmed with dose-dependence on the concentrations of SN added. SPNC of 5.0 wt% inhibited the growth of Streptococci, whereas no antimicrobial activity was shown in control PC. SPNC revealed no cytotoxic effects to HGF following ISO 10993 (cell viability > 70%). CONCLUSION: Addition of SN promoted the antibacterial activity and favored the bio-mechanical properties of PC; thus, SPNC could be a candidate for the futuristic dental biomaterial. For clinical warrant, further studies including the inhibitory mechanism, in vivo and long-term researches are still required.

Physical and Antibacterial Properties of Gold-Poly(ethyl methacrylate) Nanocomposites Prepared by In-Situ Polymerization.

In this paper, the physical and antimicrobial properties of gold-poly(ethyl methacrylate) nanocomposites (Au-PEMA) are evaluated. Characterization of gold nanoparticles was carried out based on UV-Vis spectroscopy and transmission electron microscopy (TEM). The specimens were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and field emission scanning electron microscope (FE-SEM). We identified the thermal stability of Au-PEMA nanocomposites and the inhibitory effect of live bacterial attachment of Au-PEMA nanocomposites against S. mutans was also evaluated.

Characterization and bacterial anti-adherent effect on modified PMMA denture acrylic resin containing platinum nanoparticles.

PURPOSE: This study characterized the synthesis of a modified PMMA (Polymethyl methacrylate) denture acrylic loading platinum nanoparticles (PtN) and assessed its bacterial inhibitory efficacy to produce novel antimicrobial denture base material. MATERIALS AND METHODS: Polymerized PMMA denture acrylic disc (20 mm × 2 mm) specimens containing 0 (control), 10, 50, 100 and 200 mg/L of PtN were fabricated respectively. The obtained platinum-PMMA nanocomposite (PtNC) was characterized by TEM (transmission electron microscopy), SEM/EDX (scanning electron microscope/energy dispersive X-ray spectroscopy), thermogravimetric and atomic absorption spectrophotometer analysis. In antimicrobial assay, specimens were placed on the cell culture plate, and 100 µL of microbial suspensions of S. mutans (Streptococcus mutans) and S. sobrinus (Streptococcus sobrinus) were inoculated then incubated at 37℃ for 24 hours. The bacterial attachment was tested by FACS (fluorescence-activated cell sorting) analysis after staining with fluorescent probe. RESULTS: PtN were successfully loaded and uniformly immobilized into PMMA denture acrylic with a proper thermal stability and similar surface morphology as compared to control. PtNC expressed significant bacterial anti-adherent effect rather than bactericidal effect above 50 mg/L PtN loaded when compared to pristine PMMA (P=.01) with no or extremely small amounts of Pt ion eluted. CONCLUSION: This is the first report on the synthesis and its antibacterial activity of Pt-PMMA nanocomposite. PMMA denture acrylic loading PtN could be a possible intrinsic antimicrobial denture material with proper mechanical characteristics, meeting those specified for denture bases. For clinical application, future studies including biocompatibility, color stability and warranting the long-term effect were still required.

Treatment of dental implant-related maxillary sinusitis with functional endoscopic sinus surgery in combination with an intra-oral approach.

The present report describes the case of a patient who underwent maxillary sinusitis right after dental implant installation with sinus lifting. Computed tomography scan revealed a dental implant (#16) was protruded inside the right maxillary sinus and confirmed the obstruction of ostium. A symptom remission was gained with the dual approaches combined by functional endoscopic sinus surgery and an intra-oral approach. Fully recovered function and healing of sinus were identified after 10 months follow-up. We report the case of sinusitis caused by protrusion of implants with sinus floor lift procedures and propose that practitioners should be aware of the possible its complications and management.

Antifungal and physical characteristics of modified denture base acrylic incorporated with silver nanoparticles.

OBJECTIVE: This study evaluated the antifungal and physical characteristics of denture base acrylic combined with silver nanoparticles. MATERIALS AND METHODS: Polymerized denture acrylic disc specimens containing 0 (control), 1.0, 5.0, 10.0, 20.0 and 30.0 wt% of silver nanoparticles were placed on separate culture plate dish and 100 ìL samples of yeast suspension of Candida albicans strain were inoculated on each specimens and incubated at 37°C, for 24 h. The antifungal effects were evaluated as a number of viable cells in retrieved fungal suspension. To characterize physical aspects, specimens were tested for elution of silver cation (Ag(+)) at 24 h and 30th day, thermal analysis (TG/DTA), scanning electron microscope and energy dispersed X-ray analysis (SEM/EDX) and color stability. RESULTS: Significant reduced CFU was exhibited at 20.0 and 30.0 wt% of silver nanoparticles incorporated (p < 0.01) and Ag(+) elution from specimens (maximum 0.356 ± 0.11 mg/L) contributed little to the antifungal activity considering MIC of Ag(+) in this study (3.0 mg/L). The successful synthesis of modified denture acrylic containing silver nanoparticles was accessed by TG/DTA and EDX analysis. CONCLUSION: The modified denture base acrylic combined with silver nanoparticles displayed antifungal properties and acted like latent antifungal material itself with low-releasing Ag(+), however, the improvement of poor color stability was still required.

Anti-cancer properties of glucosamine-hydrochloride in YD-8 human oral cancer cells: Induction of the caspase-dependent apoptosis and down-regulation of HIF-1α.

Evidence suggests anti-tumor activities of glucosamine-hydrochloride (GS-HCl). In the present study, we investigated anti-proliferative, growth suppressive and/or pro-apoptotic effects of GS-HCl on YD-8 human oral squamous cell carcinoma (OSCC) cells. Fundamentally, treatment with GS-HCl strongly inhibited proliferation and induced apoptosis in YD-8 cells, as determined by MTS and DNA fragmentation analyses. Of further note, as measured by Western analyses, GS-HCl treatment led to activation of caspase-3, cytosolic accumulation of cytochrome c, down-regulation of Mcl-1 and HIF-1α, up-regulation of GRP78, an indicator of ER stress, and generation of ROS in YD-8 cells. Importantly, results of pharmacological inhibition studies showed that treatment with z-VAD-fmk, a pan-caspase inhibitor, but not with vitamin E, an anti-oxidant strongly blocked the GS-HCl-induced apoptosis in YD-8 cells. Analyses of additional cell culture works further revealed that GS-HCl had a strong growth suppressive effect on not only YD-8 but also YD-10B and YD-38, two other human OSCC cell lines. These findings collectively demonstrate that GS-HCl has anti-proliferative, anti-survival, and pro-apoptotic effects on YD-8 cells and the effects appear to be mediated via mechanisms associated with the mitochondrial-dependent activation of caspases, down-regulation of Mcl-1, and induction of ER stress. Considering HIF-1α as a tumor angiogenic transcription factor, the ability of GS-HCl to down-regulate HIF-1α in YD-8 cells may further support its anti-cancer property. It is thus suggested that GS-HCl may be used as a potential anti-cancer drug against human OSCC.

Arthroscopic management of stiff elbow.

Elbow stiffness is a common problem encountered by orthopedic surgeons. Various management options have been described in the literature, including conservative measures and open and arthroscopic surgery. Arthroscopic management of stiff elbow remains controversial. The purpose of this study was to evaluate the functional results of arthroscopic management of stiff elbow.Thirty patients with stiff elbow underwent arthroscopic release surgery and were followed up for an average of 27.3 months. Surgery included anterior and posterior capsular release, coronoid process debridement, bony spur excision, and loose body removal. Postoperative outcome was assessed using the Mayo Elbow Performance Score and range of motion at the elbow. Mayo Elbow Performance Score increased from a mean 64.5 preoperatively to a mean 83.17 postoperatively. Range of motion also improved, from a mean preoperative extension and flexion of 22.83° and 96.83°, respectively, vs a mean 10.83° and 120.84°, respectively, at final follow-up. No intra- or postoperative complication was seen in any case. Underlying etiology and timing of surgery influenced the end result, with better results seen in patients with traumatic etiology and those with a shorter duration of symptoms.Arthroscopic release allows good visualization and rectification of intra-articular pathology and is a safe and effective tool for the management of stiff elbow.

In vitro antimicrobial effect of the tissue conditioner containing silver nanoparticles.

PURPOSE: The aim of this study was to identify in vitro antimicrobial activity of the tissue conditioner containing silver nanoparticles on microbial strains, Staphylococcus aureus, Streptococcus mutans and Candida albicans. MATERIALS AND METHODS: Experimental disc samples (20.0×3.0 mm) of tissue conditioner (GC Soft-Liner, GC cooperation, Tokyo, Japan) containing 0.1 - 3.0% silver nanoparticles (0%: control) were fabricated. Samples were placed on separate culture plate dish and microbial suspensions (100 µL) of tested strains were inoculated then incubated at 37℃. Microbial growth was verified at 24 hrs and 72 hrs and the antimicrobial effects of samples were evaluated as a percentage of viable cells in withdrawn suspension (100 µL). Data were recorded as the mean of three colony forming unit (CFU) numerations and the borderline of the antimicrobial effect was determined at 0.1% viable cells. RESULTS: A 0.1% silver nanoparticles combined to tissue conditioner displayed minimal bactericidal effect against Staphylococcus aureus and Streptococcus mutans strains, a 0.5% for fungal strain. Control group did not show any microbial inhibitory effect and there were no statistical difference between 24 hrs and extended 72 hrs incubation time (P > .05). CONCLUSION: Within the limitation of this in vitro study, the results suggest that the tissue conditioner containing silver nanoparticles could be an antimicrobial dental material in denture plaque control. Further mechanical stability and toxicity studies are still required.

Aspirin induces apoptosis in YD-8 human oral squamous carcinoma cells through activation of caspases, down-regulation of Mcl-1, and inactivation of ERK-1/2 and AKT.

NSAIDs and COX-2 inhibitors show anti-cancer activities in many cancer cells. In this study, we investigated the effects of NSAIDs (aspirin or indomethacin) and COX-2 inhibitor (NS-398) on growth of YD-8 human oral squamous carcinoma cells. Interestingly, among drugs tested, aspirin showed strongest inhibitory effects on viability and survival of YD-8 cells. Profoundly, aspirin treatment resulted in severe cell shrinkage and nuclear DNA fragmentation in YD-8 cells, suggesting the aspirin-induced apoptosis in YD-8 cells. Data of Western blot further demonstrated that aspirin treatment caused activation of caspases, down-regulation of Mcl-1 protein, dephosphorylation of ERK-1/2 and AKT, and also IkappaB-alpha proteolysis-dependent NF-kappaB activation in YD-8 cells. Aspirin, however, had no effect on expressions of Bcl-2, XIAP, and HIAP-1 in YD-8 cells. Importantly, pretreatment with z-VAD-fmk, a pan-caspase inhibitor blocked the aspirin-induced apoptosis and Mcl-1 down-regulation in YD-8 cells. These findings collectively suggest that aspirin induces apoptosis in YD-8 cells and the induction may be correlated to activation of caspases, caspase-dependent Mcl-1 proteolysis, inactivation of ERK-1/2 and AKT, and activation of NF-kappaB. It is suggested that aspirin may be applied a potential anti-cancer drug against human oral squamous carcinoma.

Manganese-mediated up-regulation of HIF-1alpha protein in Hep2 human laryngeal epithelial cells via activation of the family of MAPKs.

High exposure of manganese is believed to be a risk factor for respiratory diseases. Evidence suggests that overexpression of HIF-1alpha transcription factor is linked to pulmonary inflammation and vascular change. In this study, we investigated the effect of manganese-chloride (manganese) on expression and activity of HIF-1alpha in various human airway cells, including Hep2 (laryngeal), H292 (bronchial), and A549 (lung). Profoundly, while manganese treatment led to low or little effect on induction of HIF-1alpha protein in H292 or A549 cells, it strongly induced HIF-1alpha protein expression in Hep2 cells. Mn treatment, however, did not induce HIF-1alpha mRNA expression in Hep2 cells. Luciferase experiments further demonstrated that manganese treatment increased the HRE-driven luciferase activity, suggesting that the induced HIF-1 is functional. Interestingly, manganese treatment also caused activation of p38 MAPK, JNK-1/2, ERK-1/2, and ATF-2, but not of PKB or NF-kappaB in Hep2 cells. Importantly, the manganese-mediated expression and activity of HIF-1alpha protein were largely blocked by treatment with the inhibitor of p38 MAPK (SB203580), JNK-1/2 (SP600125), or ERK-1/2 (PD98059), suggesting roles of these MAPKs in the manganese-induced HIF-1alpha protein expression and activity. Moreover, treatment with SP600125 or SB203580, but not PD98059, had partial inhibitory effects on the stability of HIF-1alpha protein induced by manganese, suggesting that p38 MAPK and JNK-1/2 also contribute to the Mn-mediated HIF-1alpha protein stability. These results suggest that manganese is able to up-regulate HIF-1alpha at the protein level in Hep2 cells and the up-regulation is largely dependent of activities of the family of MAPKs.

Differential down-regulation of COX-2 and MMP-13 in human skin fibroblasts by glucosamine-hydrochloride.

BACKGROUND: Evidence suggests anti-inflammatory effects of glucosamine (GS) on inflammatory diseases. COX-2 is an enzyme to produce prostaglandins. MMPs are the family of matrix metalloproteinases degradable of ECM. Excess expression of COX-2 or MMPs involves in skin inflammation. OBJECTIVE: We evaluated whether GS-HCl modulates expression of COX-2 and/or MMPs by IL-1beta or PMA in human skin fibroblasts (HSF) or keratinocytes (HaCaT). METHODS: HSF or HaCaT cells were exposed to IL-1beta or PMA without or with GS-HCl. COX-2 or MMPs protein and mRNA expression, respectively, were analyzed by Western blot and RT-PCR. MTS assay was utilized to assess the cytotoxicity of GS-HCl on HSF cells. RESULTS: In HSF cells, IL-1beta treatment induced COX-2 and MMP-13 expressions in association with activation of ERKs, p38 MAPK, JNKs, and NF-kappaB. PMA treatment also induced COX-2 and MMP-13 expressions in association with p38 MAPK activation. Of interest, treatment with GS-HCl (10mM) led to blockage of p38 MAPK activation, accumulation of 66kDa COX-2 protein variant (without affecting COX-2 mRNA expression), and transcriptional down-regulation of MMP-13 in the IL-1beta- or PMA-treated HSF cells. Distinctly, pharmacological inhibition of p38 MAPK with SB203580 was associated with transcriptional down-regulation of COX-2 and MMP-13 in the IL-1beta- or PMA-treated HSF cells. In addition, the GS-HCl-mediated COX-2 protein modification was observed in both endogenous and PMA-induced COX-2 in HaCaT cells. CONCLUSIONS: GS-HCl differentially down-regulates COX-2 and MMP-13 expression in the IL-1beta- or PMA-treated human skin fibroblasts via the p38 MAPK-independent COX-2 translational inhibition and the p38 MAPK-dependent MMP-13 transcriptional suppression, respectively.

Effects of dentin bonding agents on bonding durability of a flowable composite to dentin.

The present study evaluated the bonding durability of a flowable composite on bovine dentin using dentin bonding agents with different numbers of application steps: Scotchbond Multipurpose (three steps), Prime & Bond NT and One-Step (two steps), AQ Bond and Prompt L-Pop (one step). Shear bond strength tests were performed, and resin-dentin interface and fracture mode were observed. There were no significant differences in bond strength among the specimens within 37 degrees C storage group (p > 0.05) and post-thermocycling group, except between Prompt L-Pop and Scotchbond Multipurpose (p < 0.05) in the post-thermocycling group. Further, Scotchbond Multipurpose and One-Step showed significantly lower bond strengths after thermocycling (p < 0.05). It was thus shown that the use of simplified bonding agents did not necessarily improve the bonding strength of flowable composites.