PURPOSEThis 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 METHODSChemically 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.RESULTSXRD 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%).CONCLUSIONAddition 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.
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. Electronic supplementary material The online version of this article (10.1186/s12903-019-0837-y) contains supplementary material, which is available to authorized users.
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.
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