The aim of the present study was to investigate the effects of the type and thickness of the zirconia material on the microhardness of the underlying dual-cure resin cement.α=.05). Eight disk-shaped zirconia specimens with a 4-mm diameter and four varying thicknesses  were fabricated from two different monolithic zirconia materials: posterior monolithic zirconia (Prettau) and anterior monolithic zirconia (Prettau Anterior). Dual-cure resin cement specimens with a 4-mm diameter and 5-mm height were prepared using Teflon cylinder molds and activated by light beneath the eight zirconia disks and without any zirconia disk for 20 s (n=12). A total of 108 specimens were embedded in acrylic. Vickers hardness of each specimen was measured at three different depths using a microhardness device with a 50-g load. All data were statistically evaluated using three-way ANOVA, one-way ANOVA, independent samples t-tests, and Bonferroni corrected post hoc tests ( Dual-cure resin cement's microhardness was significantly higher for the samples polymerized beneath anterior monolithic zirconia compared to posterior monolithic zirconia. The hardness decreased as the thickness increased for both types of zirconia; the latter was attributed to an attenuated curing efficiency. Microhardness of the dual-cure resin cement is influenced by both the type and the thickness of the monolithic zirconia restoration. Polymerization efficiency for resin cement cured under anterior monolithic zirconia may be superior to cured beneath posterior monolithic zirconia. Densely sintered yttria-stabilized zirconia ceramics (Y-TZP) have been widely used as alternatives to metal-ceramic restorations because of their superb mechanical properties and favorable esthetic characteristics , 2. TheyEither type of zirconia-based restorations can be cemented using either conventional or adhesive techniques . AdhesivVarious novel monolithic zirconia materials with different compositions and relatedly translucencies are available in the dental market. However, the effect of their type and thickness on the polymerization competence of resin-based cements remains to be a subject of interest. Therefore, the purpose of the current study was to investigate the microhardness of dual-cure resin cement used underneath anterior and posterior monolithic zirconia materials with different thicknesses. The null hypothesis of the study was that the microhardness of dual-cure resin cement is not affected by the type and the thickness of the overlying monolithic zirconia material.Eight disks with a 4-mm diameter and varying thicknesses were prepared from two types of monolithic zirconia materials ; four PRThe total thickness of all zirconia disks was measured by a digital caliper. Then, the outer disk surfaces were glazed  in accordance with the manufacturer's directions.2 was used with an exposure time of 20 s. Calibration of the curing device was checked before polymerization by contacting the tip of the light to a built-in light meter.In total, 108 resin samples were prepared by the placement of dual-cure resin cement  in cylindrical polytetrafluoroethylene (PTFE) molds with standard dimensions (4.0-mm diameter and 5.0-mm height). For the preparation of resin specimens, a glass slide placed against a black background was used in order to support the surface and reduce the reflectance of the subjacent surface against each sample. A transparent film strip was placed on the glass slide to avoid bonding of the material. Equal amounts of base and catalyst were mixed according to the manufacturer's recommendations. The PTFE cylinder mold was filled with resin cement. One more transparent film strip was placed on top, followed by another microscope slide, using finger pressure. Excess cement material was removed from the mold by pressing the film strips between the glass slides. Following removal of the excess cement, one of the eight ceramic disks was placed on top, and the tip of the light source was smoothly located on top of the zirconia disk. This would allow light to pass through the disk over the material . Resin sSubsequently, the resin cement samples were taken out of the PTFE molds, and a plastic spatula was used to remove the uncured material according to ISO 4049 guidelines . The curμm below this zero point using a microhardness tester  with a 50-g load applied for 15 s in the cross-sectional area. Three measurement depths were set by using the positioning knobs on the tester machine and the indentations were conducted by a pyramid-shaped microdiamond tip in order to give the hardness value  in cylindrical molds . To prep Figures  and 4. Tα=.05).VHNs obtained at different depths of dual-cure resin cement samples under different types and thicknesses of zirconia disks were statistically analyzed using three-way ANOVA in order to determine the effect of the zirconia type, specimen thickness, and measurement depth on VHN. The two-way interaction among groups was analyzed using independent sample t-tests, one-way ANOVA, and Bonferroni corrected post hoc tests   on VHN of the resin cement. According to three-way ANOVA, the analysis model was significant, with an Rμm  and VHN values of the dual-cure resin was significantly higher with PRA disks than with PRZ disks at measurement depths of 100, 300, and 500 μm . VHN showed a significant decrease with an increase in the measurement depth (p<0.001) for all groups polymerized under both PRA and PRZ discs whereas the difference was not significant for 100- and 300-μm measurements of control group. For the groups polymerized beneath PRZ and PRA disks, VHN at a 100-μm depth was significantly higher than that at 300- and 500-μm depths, that at a 300-μm depth was significantly higher than that at a 500-μm depth  was used in order to keep the focus on the difference between anterior and posterior monolithic zirconia. However, there are more factors that could affect the polymerization of the resin cement cured beneath zirconia-based restorations. In order to develop clinical recommendations, further studies are needed to confirm our results through comparisons of monolithic zirconia materials with different brands, compositions, and shades when luted using resin cements with differing ratios of chemical and light-activated components.Within the limitations of the study, the following conclusions can be drawn: microhardness values of dual-cure resin cement samples polymerized beneath PRA based materials were higher than that of resin cement samples polymerized under PRZ based materials for the same material thickness and measurement depth. Increase in zirconia thickness leads to significantly lower microhardness values for the underlying resin cement for both PRA and PRZ materials. Clinicians should consider that an increase in the thickness of both PRA and PRZ based restorations could result in insufficient light transmission, which affects the long-term durability of the resin cement and restoration. On the basis of this finding, clinicians can select a better material for each given situation, and they should also consider the efficiency of light curing under thicker zirconia restorations.


The impact of hydroxypropylsulfonation/caproylation on the adhesion of cornstarch to polylactic acid (PLA) fibers was investigated for ameliorating the applications such as PLA sizing. The hydroxypropylsulfonated and caproylated cornstarch (HCS) samples with different degrees of substitution (DS) were synthesized by a hydroxypropylsulfonation of acid-converted cornstarch (ACS) with 3-chloro-2-hydroxy-1-propanesulfonic acid sodium salt (CHPS-Na) and subsequently a caproylation with caproic anhydride (CA). The HCS granules were characterized by Fourier transform infrared spectroscopic and scanning electron microscopy. The adhesion was evaluated by measuring the bonding forces of the PLA roving impregnated. The mechanical behaviors of the adhesive layers were estimated by determining the properties of the films. The results of adhesion measurement were also analyzed especially through the wetting and spreading of the paste on the fiber surfaces, as well as the failure type, internal stress and mechanical behaviors of the adhesive layers among fibers. Additionally, apparent viscosity and its stability of the pastes were also determined. It was found that hydroxypropylsulfonation/caproylation was not only able to obviously improve the adhesion of ACS to PLA fibers, but also capable of further improving the adhesion of hydroxypropylsulfonated starch (HS) to the fibers. With the rise in the total DS, the adhesion gradually increased. The two substituents improved the wetting and spreading, reduced the internal stress, lowered the probabilities of interfacial failure and cohesive failure, decreased the film brittleness, and increased the van der Waals force at the interfaces. Moreover, the HCS samples with a stability of above 85% could meet the demand on the stability for sizing. Considering the experimental results of the adhesion and the analysis of the results, HCS showed potential in the application of PLA sizing. It conslinkages . It is alinkages , low coslinkages ,6, envirlinkages ,8. Howevlinkages . This islinkages ,10, resuSufficient adhesion to fibers has been perceived to be a valuable behavior for starch used for sizing in textiles and papermaking . In thesDue to the similarity with the polyethylene terephthalate, eco-friendly nature, and ease of processing, polylactic acid (PLA) obtained from renewable resources has been extensively explored for fiber applications . CurrentCurrently, there is no study that has tested hydroxypropylsulfonation together with caproylation as the hydrophilic and hydrophobic derivatization to starch. Accordingly, an important aim of this work is to reveal if the PSH and caproate substituents chemically attached to starch chains are able to enhance the adhesion of cornstarch to PLA fibers and film properties and to determine if the HCS has a better adhesion compared with hydroxypropylsulfonated starch (HS), which has a good adhesion to cotton fibers. Another objective is to determine the optimal level of starch modification for the HCS because the functional ability of modified starch is related to the degree of substitution (DS) of the substituents introduced . The obtRaw cornstarch (food grade) with a moisture content of 12.1 wt% and an apparent viscosity of 60 mPa·s, was obtained from Shandong Hengren Industry and Trade Co., Ltd. . Prior to use, the starch was refined to get rid of the protein substance  and subsThe HCS was synthesized by reacting acid-converted cornstarch (ACS) with CHPS-Na and further caproylation with CA in an aqueous medium.w/w) ACS aqueous dispersion was prepared by dispersed dried ACS (200 g) in distilled water containing Na2SO4 (20 g). The dispersion was transferred into a 1000 mL four-necked round-bottom flask, regulated at pH = 10–11 with a 3% (w/w) NaOH solution, and then heated to 45 °C in a water bath under the continuous stirring condition. Subsequently, the mixture of CHPS-Na (15 g) and NaOH (3 g) was dissolved in distilled water (30 mL) and added immediately into the dispersion. The reaction was performed at 45 °C for 6 h in the pH = 11.5–12.5 under mechanical agitation. The dispersion was neutralized to approximately pH = 7 using dilute HCl solution, vacuum-filtered, and washed three times with 75% ethanol-distilled water followed by being oven-dried at 45 °C, ground, and sieved with a 100-mesh sieve.Briefly, a 40% (w/w) dispersion. The dispersion was regulated at pH = 8–9 using a 2% (w/w) NaOH aqueous solution. After the dispersion was heated to 30 °C under continuous agitation, CA was added slowly, meanwhile, the pH of the dispersion was maintained in a range of 8–9 by addition of the 2% (w/w) NaOH solution. After the addition, the reaction was kept at 30 °C for 0.5 h, and then the dispersion was neutralized using dilute HCl solution to approximately pH = 7. Finally, the product was vacuum-filtered, washed three times with 75% ethanol-distilled water followed by being oven-dried at 45 °C, ground, and sieved with a 100-mesh sieve for obtaining the HCS.Subsequently, the HS prepared above was subjected to the caproylation with CA to introduce caproates into the starch molecules. The HS was dispersed in isopropyl alcohol to form a 40%  and 138 represent the sulfur content and molecular weight of –CH2CH(OH)CH2SO3H minus that of the hydrogen atom, respectively.DSanalysis  and calcc indicated the numbers of caproates introduced into the starch molecules. Back titration with HCl preceded by alkali saponification [c. The caproate content  and its DSc value were calculated with the following equations (2) and (3), respectively: V1 and V2 denote the volumes of HCl consumed in blank and sample titration; N is the concentration of HCl solution; 0.099 corresponds to the grams in 1 mL of 1.000 mol/L HCl solution; 9900 is the molecular weight of caproate × 100; and 98 is the molecular mass of caproate introduced minus that of hydrogen atom.DSfication  was empl−1 with the resolution of 4 cm−1.The infrared spectra of ACS and HCS samples were carried out on an IRPrestige-21 FTIR Spectrometer  to demonstrate the successful introduction of new functional substituents in the starch molecules after hydroxypropylsulfonation/caproylation. After the powdered ACS and HCS samples were ground with potassium bromide (KBr), respectively, and subsequently pressed into pellets, the spectra were recorded by scanning the pellets in the range from 500 to 4000 cmThe surface morphology of the granular ACS and HCS samples, as well as the cross-section of ACS, HS and HCS film samples, were analyzed by an S-4800 scanning electron microscope . Prior to the analysis, all of the samples were sputter coated with a thin layer of gold to avoid charge accumulation.w/w)) was performed on an NDJ-79 Rotary Viscometer  at 95 °C with a shear rate of 2028 s−1  [The determination on the apparent viscosity of gelatinized starch paste (6% (0 mPa·s) .The surface tension of cooked starch paste was determined with a DCAT 21 Automatic Tensiometer . A 1 wt% starch aqueous paste was prepared by heating the 1% starch aqueous dispersion to 95 °C and kept at this temperature for 1 h. After cooling down, the tension was determined at room temperature.A legal standard method (FZ/T 15001-2008) was adopted to conduct the adhesion measurement. In the measurement, the bonding force of starch samples to PLA fibers was employed to indicate the adhesion. Firstly, a 1% dispersion was prepared by dispersing dried starch samples (7 g) in distilled water. The dispersion was thoroughly stirred and heated to 95 °C for 1 h to form a 1% sample aqueous paste. Afterward, the aqueous paste was used to impregnate roving that had been carefully wound onto a frame for 5 min. Then the roving impregnated was air-dried at room temperature. The dried roving was kept at 65% relative humidity (RH) and 20 °C for at least 24 h, and their bonding forces were measured using a YG026D Electronic Strength Tester  with an initial chuck-distance of 100 mm and a drawing speed of 50 mm/min at the same ambient condition according to the literature . In eachThe preparation was carried out according to our previous work . The filThe tensile properties were estimated via determining the tensile strength and elongation at break of the films. Before being determined, the 200 mm × 10 mm strips were maintained at 20 °C and 65% RH for 24h. The determination was carried out on the YG026D Electronic Strength Tester in an initial chuck-distance of 100 mm and a stretching speed of 50 mm/min according to the ASTM D 882-02 method. The results reported were the averages of twenty samples.θ) of 10° to 45°.The diffraction behavior of ACS and HCS films was analyzed by XRD-6000 X-ray Diffractometer  with a wavelength of 0.154 nm CuKa radiation at generator settings of 40 kV and 30 mA. The scanning region of diffraction was registered with a scanning rate of 4°/min and an angular step of 0.02° at Bragg angle (2−1 was attributed to the characteristic absorption band of C=O [−1 corresponded to the symmetric stretching vibration of sulfonic ions [The introduction of PSH substituents and caproates onto starch chains was demonstrated by FTIR spectra of HCS (curve a) and ACS (curve b), as depicted in d of C=O  in the cnic ions , which vIt has been concluded that chemical modification is able to involve physical and chemical phenomena on the granule surface of starch . SEM hasp and DSc) values of granular HCS samples are measured, as shown in p was a fixed 0.029 prepared by reacting ACS with 15 g of CHPS-Na, with the increases in the amount of CA to starch, the DSc, i.e., level of starch caproylation, gradually increased. Therefore, it could be imagined that HCS samples with gradually increased total DS (the sum of DSp and DSc) values from 0 to 0.087 could be obtained as the amount of the CA increased.The total DS , light transmittances of the starch pastes gradually decreased. Commonly, the lower the transmittance, the worse the water-dispersibility [Obviously, the substituents introduced can interfere with the re-association of the hydroxyls and alleviate the parallel arrangement of the amyloses through their steric hindrance, thereby favoring to alleviate the retrogradation . As a resibility . Therefosibility , therebyIn general, the cohesive failure of an adhesive joint is also correlated with the mechanical properties of the adhesive layers existed among fibers . AccordiDuring the formation of the film or the adhesive layer, the amylose chains in the aqueous paste regularly arrange with each other by hydrogen bonding between the hydroxyls and form a three-dimensional network structure . It is tBased on the previous results and discussions, it could be concluded that introducing caproates and PSH substituents into starch molecules via hydroxypropylsulfonation and caproylation of ACS with CHPS-Na and CA was an effective manner to improve the adhesion of starch to PLA fibers for ameliorating its end-use ability in the applications such as PLA warp sizing and papermaking. The bonding forces of HCS  to PLA fibers were superior to those of ACS (DS = 0) and HS (DS = 0.029), indicating hydroxypropylsulfonation/caproylation was not only able to improve the adhesion of starch to PLA fibers, but also able to further improve the adhesion compared with the HS. The adhesion of HCS to PLA fibers was correlated with the total DS, and the forces gradually increased as the total DS raised. In addition, all of the HCS samples had the stability of above 85%, indicating that the introduction of the substituents could meet with the requirement in the stability for warp sizing. The elongation at break of the HCS film was higher than ACS film, and tensile strength and degree of crystallinity of the film were inferior to those of ACS. These suggested that caproates and PSH substituents derivatized were capable of reducing the brittleness of the film, and providing a toughening effect on the film adopted to evaluate the mechanical properties of HCS adhesion layers. The toughening effect provided by the two substituents indicated that they are capable of reducing the internal stresses within the matrix of the adhesive layers, thereby diminishing the probability of cohesive failure within the matrix of the adhesive layer, and favoring the adhesion. Moreover, the substituents not only favor alleviating the retrogradation through interfering with the re-association of the hydroxyls and alleviating the parallel arrangement of the amyloses but also favor reducing the surface tension of cooked starch paste; thereby, favoring the amelioration in the wetting and spreading and subsequently lowering the probability of interfacial failure. Hydrophobic caproates that contain ester groups also favor increasing the van der Waals force at the interfaces between starch adhesive layers and PLA fibers. For these reasons, the modification improved the adhesion. Considering the results of HCS in the paste stability, adhesion, film properties, as well as preparation cost, thus HCS with a total DS of 0.070 showed potential in the applications of PLA sizing.


In the present study, the functional and biological properties of zirconia implants were analyzed thorough in vitro and in vivo studies. The proliferation properties of periodontal cells on the discs of machined surface titanium, hydroxyapatite coated titanium and zirconia were analyzed, and zirconia was shown to be favorable. In addition, small implant fixtures that can be applied to the jawbone of mice were manufactured and transplanted to C57BL/6 mice. The adhesion molecules expression patterns in peri-implant mucosa suggest a stronger mucosal seal and more adequate prevention of peri-implant epithelium (PIE) elongation in the zirconia implant when compared with other conventional materials. Differential laminin-332 expression in peri-implant mucosa of zirconia implants seems to regulate the PIE elongation. In conclusion, zirconia was found to be promising and advantageous with regards to the mucosal seal. And biological width (BW) of peri-implant mucosa is more desirable in zirconia implants compared to conventional titanium implants.Zirconia implants have become an alternative to titanium implants due to several advantages. The zirconia implant is relatively esthetic and highly resistant to bacteria. While biomaterial studies for zirconia implants have considerably accumulated,  Since the introduction of dental implants for clinical applications, titanium has been considered the standard material for the treatment of edentulous jaws . The useIn order to overcome these criticisms, the modification of the implant surface has been studied and applied to improve the biological surface properties favoring osseointegration  or bacteZirconia implants have become an alternative to titanium implants due to several advantages . TitaniuThe causes of periodontal and peri-implant diseases are various and include environmental factors such as smoking, local factors such as oral bacterial flora, and systemic factors such as nutritional status, hematologic disorder and hormonal abnormality . The majBiological width (BW) is defined as the dimension of the soft tissue, which is attached to the portion of the tooth coronal to the crest of the alveolar bone . The BW The aims of the present study were (1) to determine the characteristics of periodontal cells on zirconia, hydroxyapatite coated titanium and machined surface titanium, (2) to evaluate the expression of mucosal adhesion molecules including laminin-332 around zirconia and other implants, (3) to describe the ratio of epithelium and connective tissue within the soft tissue attachment on the zirconia and other implants and (4) to provide evidence for determining which material is more advantageous for clinical use.In the present study, small implant fixtures that can be applied to the jawbone of mice were manufactured. There were differences in the composition of the biological width according to the materials. The expression of the adhesion molecule forming the mucosal seal was also slightly different. In addition, the evidence suggested stronger mucosal seal formation with zirconia fixtures than with other materials. PIE elongation (or migration) prevention was also observed in the zirconia implant. This phenomenon appears to be related to laminin-332. Zirconia was advantageous with regards to the mucosal seal; on the bone healing side, Hydroxyapatite (HA)-coated titanium was favorable.All the animal experiments were approved by the Yonsei University Health System Institutional Animal Care and Use Committee (YUHS-IACUC) in accordance with the Guide for the Care and Use of Laboratory Animals . The animal study plan for these experiments (2016-0342) was reviewed and approved by the committee on January 28, 2017. All the experiments were performed in accordance with the guidelines of the committee.2 conditions.Human periodontal ligament fibroblasts  were purchased from ScienCell Research Laboratories  and cultured with a fibroblast medium . The immortalized human cementoblasts (ihCEMs) were obtained from professor Takata’s laboratory . ihCEMs were immortalized by transfection with the telomerase catalytic subunit, the hTERT genes . They weThe titanium discs, HA-coated discs of 10.0 mm diameter were purchased from Shinheung, Co. . The zirconia discs were made with -TZP in 10.0 mm diameter by the Dental laboratory  . The thr2 incubation, all the media were transferred to a 96-well cell culture plate . The absorbance was then measured three times at 450 nm with a microplate reader . The number of cells was measured as the survival rate with the equation below:A Cell Counting Kit-8  was used for the cell proliferation assay. All the medium was removed and 500 μL fresh medium was added to each well including an empty well for a medium background measurement (negative control). Then, 50 μL water-soluble tetrazolium salt (WST-8) reagent was added to each well including the negative control. After 1 h of COcontrol: negative control; Ablank: blank well)..Female C57BL/6 mice  were housed in a temperature-controlled room (22°C) under artificial illumination with a 12 h light/dark cycle and 55% relative humidity. The mice were provided food and water ad libitum. All the operational procedures were performed under deep anesthesia. Fifteen female mice were randomly divided into three groups , HA-coated titanium (HA) and machined surface zirconia . The tit2.The upper first molars of 6-week-old mice were extracted while under deep anesthesia and allowed to heal for 6 weeks. Under deep anesthesia, a pilot hole was made using a portable, low-speed engine with a 0.75 mm drill tip designed for HA implants. Subsequently, the fixture was transplanted into the hole using a driver . The cusThe tissues were excised and immersed in 4% paraformaldehyde (PFA). After fixation, the tissues were decalcified in 10% sodium citrate and 22.5% formic acid for 6 weeks at 4°C. Staining was performed on 6 μm paraffin-embedded sagittal  sections. After deparaffinization, the slides were incubated with Proteinase K  for 20 min at 37°C. Subsequently, the slides were incubated with antibodies against collagen IV , fibronectin , plakophilin , or laminin-5  at 4°C overnight. The specimens were sequentially incubated with secondary antibodies and streptavidin peroxidase. The results were visualized following staining with a diaminobenzidine (DAB) reagent kit . The sections were counterstained with Mayer’s hematoxylin. All the specimens were observed using a stereomicroscope .The bone area and biological widths were measured using the ImageJ shareware software . For bone area measurements, two slices with fixture diameters greater than 600 μm were selected from each dissected maxilla sample. The ROI was set from the top of the thread part of the fixture to the third thread crest and 150 μm from the surface of the fixture . The statistical analyses were performed by one-way analysis of variance (ANOVA) followed by the Student’s p < 0.01 for ihCEM and HPLF; p < 0.05 for HGF-1), and proliferation rates of all three types of cells on control dishes were higher than those of cells on discs at day 5.The ihCEMs, HPLFs and HGF-1 cells were cultured on a conventional 24-well cell culture dish (Control), machined surface titanium discs (Ti), HA-coated titanium discs (HA) or zirconia discs . All thep = 0.032, zirconia vs. HA; p = 0.064 were considered significant. At day 5, the zirconia discs (7.360 ± 0.145) had a higher cell number than Ti discs (6.304 ± 0.056) or HA discs (6.272 ± 0.288). These were statistically significant . There was no significant difference between Ti discs and HA discs.The ihCEMs proliferated more on the zirconia discs than on the Ti or HA discs at 3–5 days . The prop = 0.046). No difference was observed between zirconia and Ti discs . The zirconia discs (5.864 ± 0.088) had a higher relative number of cells than the HA discs (3.827 ± 0.025), but not higher than Ti discs (5.589 ± 0.034) at day 3. Zirconia vs. Ti; p = 0.160, zirconia vs. HA; p = 0.009 was considered statistically significant. At day 5, the zirconia discs relative number of cells (10.420 ± 0.194) was higher than on Ti discs (9.070 ± 0.102) or HA discs (7.611 ± 0.128). These were statistically significant .The HPLFs on zirconia showed similar patterns to ihCEMs. Among the three types of discs, zirconia had the highest proliferation rate . Up to dp = 0.037, zirconia vs. HA; p = 0.051). At day 5, the relative cell number on the zirconia discs (1.801 ± 0.044) was higher than on Ti discs (1.376 ± 0.043) or HA discs (1.670 ± 0.033). These were statistically significant . There was no difference among the three discs at day 1. Unlike the other two cells, the proliferation of HGF-1 on the discs was significantly lower than the proliferation on the control dish.HGF-1 cells proliferated twice more on the control dish than on the experimental discs . Among tTo investigate the bone healing and osseointegration of the implant, three different types of fixtures were used in this study. HA fixture surface was rugged and considered to be a relative high surface area, while Ti and zirconia fixture had flat machined surfaces .Four transplanted Ti fixture samples and four zirconia fixture samples were harvested from each of the five transplanted mice . All five HA fixtures were harvested without dislocation. Hematoxylin and eosin (HE) staining showed bone healing between the alveolar bone and the fixture . The alvin vivo transplantation was analyzed. IHC against collagen IV, fibronectin, plakophilin and laminin-332 was performed. In the natural tooth, collagen IV was strongly expressed both at the tooth contact surface of the junctional epithelium (JE), which is called the internal basal lamina (IBL), and the ECM of connective tissue cells under the JE  molecules after r the JE . Fibroner the JE . Fibroner the JE . Lamininr the JE . The conr the JE –d.Unlike in the natural tooth, strong collagen IV expression was not observed along the contact surface of the PIE in the three types of fixtures . It was The expression of fibronectin around the Ti and HA implant fixtures was similar to that of the natural tooth . Some suUnlike other ECM molecules, laminin-332 was expressed along the implant fixture and PIE interface (IBL), similarly, as on the JE of the natural tooth . The EBLThe length of the PIE of healed mucosa varied according to the type of fixture. The PIE elongation was checked on the mesial and distal sides of transplanted fixtures. PIE elongation was defined when the PIE made contact with the fixture and grew along the fixture surface more than 350 μm from the top. PIE elongation on the Ti fixture was observed at 14 sites in 16 mesial and distal sites of four mice. p < 0.005). The ratio difference among the other groups except the Ti fixture was not significant. The mean BWs measured 402.55 μm in the natural tooth, 728.48 μm in Ti, 657.68 μm in HA, and 685.63 μm in zirconia.The composition of the biological width (BW) was analyzed. From the top of the JE or PIE to the alveolar crest level, the heights of epithelium and connective tissue were measured . The ratin vivo studies had not been performed yet. The present study is the first in vivo investigation using a small zirconia implant fixture in the mouse oral cavity. Dental implants require a mucosal seal to inhibit epithelial elongation and bacterial invasion of subepithelial connective tissues and implant interfaces . However, this difference between zirconia and Ti fixtures is not likely to be clinically meaningful.In the present study, bone healing of HA fixture was completed, while the bone healing of zirconia and Ti was not completed within 8 weeks. At the initial bone healing rate, HA fixture was the best among the three types of fixtures. It is well known that HA-coating on the implant surface induces rapid bone healing and shortens the time to initial loading . The disThe mucosal seal between the implant and adjacent mucosa is closely related to the initiation of peri-implantitis . The disIn the present study, collagen IV was observed at the interface of the connective tissue and the three types of fixtures. It was observed at the zirconia-PIE interface as well as the tooth-JE interface, but not at the Ti- and HA-PIE interfaces. Among the three types, collagen IV was continuously expressed both of IBL and connective tissue-fixture interface only in zirconia. Fibronectin was observed at connective tissue interface and suprabasal cells of PIE of Ti and HA fixture samples. In zirconia implants, similarly to Collagen IV, fibronectin was expressed in IBL and connective tissue interface continuously. In contrast, plakophilin, which forms hemidesmosomes, showed a similar expression pattern to a natural tooth in all three types of implant fixtures. The expression pattern of collagen IV and fibronectin in the zirconia fixture, not observed in other fixtures, suggests a stronger mucosal seal formation at zirconia implant than other Ti and HA fixtures.Laminin-332 was expressed in all IBL and EBL of JE and PIE. The expression at the interface of the connective tissue and fixture was observed to be different between the Ti and zirconia fixtures. The laminin-332 was expressed along the IBL and continued to the interface of the connective tissue and Ti fixture. The laminin-332 was also expressed strongly in the connective tissue around apical leading edge of PIE. However, it was limited to the IBL in zirconia fixtures. A previous study reported that laminin-332 induces cell migration during PIE formation after Ti implant transplantation in Rat ,b. ThesePeri-implant tissues are quite similar except for the PDL, although the nomenclature is slightly different. Therefore, the concepts of the healing process used in many periodontics can be applied to implant healing . One of The PIE serves as a primary physical barrier, but an active immune response to pathogens cannot be achieved through the PIE. Moreover, because PIE has a weaker adhesion than JE, a sufficient connective tissue site is required where blood vessels are abundantly distributed for effective protection. Therefore, the ratio of PIE in the BW should be properly maintained. In clinics, the guided tissue regeneration (GTR) procedure is used to prevent excessive migration of PIE .The BW of the Ti fixture showed a significantly low connective tissue ratio. This is due to the elongation of the PIE. This phenomenon was not observed in HA, and bone healing was sufficient before PIE elongation occurred. The BW of zirconia fixture did not show the PIE elongation, although bone healing on zirconia was delayed compared to HA fixture. The results of the proliferation assay of periodontal cells, including HGF-1, may be indirect evidence of PIE elongation limitation in zirconia fixtures. It was concluded that rapid proliferation of connective tissue might affect to prevent PIE elongation.Considering the regulation of PIE elongation by laminin-332 and the expression of adhesion molecules at the implant interface and connective tissue cell proliferation on materials, zirconia implants may tend to be more advantageous in terms of the mucosal seal than Ti implant. On the other hand, the bone contact area of the fixture appears to be advantageous for surface-treated titanium to achieve full osseointegration in a short time. To summarize these results, a new hybrid implant, a bone-contact thread portion composed of surface treated Ti alloy and a soft tissue-contact portion composed of zirconia, may have potential as a new alternative through further research.No datasets were generated or analyzed for this study.All the animal experiments were approved by the Yonsei University Health System Institutional Animal Care and Use Committee (YUHS-IACUC) in accordance with the Guide for the Care and Use of Laboratory Animals . The animal study plan for these experiments (2016-0342) was reviewed and approved by this committee on January 28, 2017. All the experiments were performed in accordance with the guidelines of this committee.D-JL, J-SR, and H-SJ conceptualized the study, designed the experiments. D-JL drafted the manuscript. D-JL and J-SR conducted the experiments. MS, K-WL, and J-ML critically revised the manuscript for intellectual content. D-JL, J-ML, and H-SJ analyzed and interpreted the results. All authors gave permission to the final draft of the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Cronobacter spp.; C. sakazakii was the most recovered species. Our findings underscore the risk for contamination of breast milk substitutes.In Bogotá, Colombia, a large number of babies are fed with breast milk substitutes made from corn and plantain starch. We found 34.3% of tested samples to be contaminated with  Cronobacter spp. is a group of emerging foodborne opportunistic pathogenic microorganisms that can cause deadly disease in neonates, children, older adults, and immunocompromised persons, including meningitis, septicemia, and necrotizing enterocolitis in neonates and infants (Cronobacter spp. is widespread in dry foods. Occurrence is higher in infant milk formula (IMF) because some species of Cronobacter are able to tolerate different types of stress in IMF; for example, C. sakazakii is able to survive up to 2 years in IMF, which increases the possibility for baby foods to become reservoirs, given that milk increases the cultivability and recovery of C. sakazakii in dry environments , breast-feeding supplementation is gradually made from birth, starting at 27% in the first months until 76% at 9 months of age . The sampling was distributed per percentage weight according to city district and starch composition. We collected 36 samples of corn starch, 53 samples of plaintain starch, and 13 samples of other starches (N = 102 samples)Cronobacter spp., we used the ISO 22964:2006 method, by which we were able to recover isolates from 35 (34.3%) samples. However, recovery was already improved in the new ISO 22964:2017 version, which is desirable because Cronobacter spp. have been found at levels of <1 UFC/100 g of IMFs . The Cronobacter species identified were C. sakazakii (74% [26/35] of isolates), C. malonaticus (14% [5/35] of isolates), and C. dublinensis (11% [4/35] of isolates)  were positive for solates) .Cronobacter spp. prevalence was similar to that reported in plant derivatives (e.g., 20.1% [Cronobacter spp. in plantain matrixes is available.The 34.3% Cronobacter spp., the international standard is a total absence in IMF (C.sakazakii, which is the species associated with the highest number of disease cases reported in neonates and whose sequence type 4 is already known to be associated with severe cases of meningitis (From the point of view of microbiologic quality, the presence of coliform bacteria and pathogens shows the risk of contamination of IMF substitutes. For Cronobacter spp. have been reported. However, Cronobacter are not subject to mandatory re-porting in Colombia because no active surveillance of this pathogen exists, and the medical community lacks information about the pathogen. It is important to char-acterize and document the presence of Cronobacter spp. in different foods to assess the risk to which children <1 year of age and breast-fed infants are exposed and to identify the connection between diseases like meningitis and the consumption of contaminated baby foods produced locally. Some measures have been proposed to mitigate this risk. It is vital to indicate on the starch packaging that starch must be reconstituted in water at >70°C for >1 minute before consumption, and starch leftovers must be refrigerated to minimize the risk for contamination with Cronobacter spp. (In Bogotá, no cases of foodborne diseases related to the presence of


Thus, while jumping performance appears to be unaffected when leg extensor muscle strength and tendon stiffness are maintained, the reduced muscular power output during lower limb multi-joint tasks seen with aging may be due to age-related changes in motor task execution strategy rather than due to muscle weakness.Reductions in muscular power output and performance during multi-joint motor tasks with aging have often been associated with muscle weakness. This study aimed to examine if matching younger and middle-aged adults for triceps surae (TS) muscle strength and tendon stiffness eliminates age-related differences in muscular power production during drop jump. The maximal ankle plantar flexion moment and gastrocnemius medialis tendon stiffness of 29 middle-aged (40–67 years) and 26 younger (18–30 years) healthy physically active male adults were assessed during isometric voluntary ankle plantar flexion contractions using simultaneous dynamometry and ultrasonography. The elongation of the tendon during the loading phase was assessed by digitizing the myotendinous junction of the gastrocnemius medialis muscle. Eight younger (23 ± 3 years) and eight middle-aged (54 ± 7 years) adults from the larger subject pool were matched for TS muscle strength and tendon stiffness  and then performed series of drop jumps from different box heights  onto a force plate (sampling frequency 1000 Hz). The matched young and middle-aged adults showed similar drop jump heights for all conditions . However, middle-aged adults showed longer ground contact times (on average 36%), lower vertical ground reaction forces (36%) and hence lower average mechanical power  independent of box height. Further, leg stiffness was lower (48%) in middle-aged compared to younger adults for all jumping conditions and we found significant correlations between average mechanical power and leg stiffness (0.70 ≤  Lower limb muscular power production is crucial for an effective and safe locomotion in sport and during activities of daily living. For example, rapid muscle force generation is required during various daily lower limb multi-joint tasks and has been identified as a predictor for mobility  and fallPrevious research suggests an age-related decline in muscular power production of the leg extensor muscles during single  and kinetics  would be eliminated when young and middle-aged adults are matched for triceps surae (TS) isometric muscle strength and tendon stiffness, in order to test the hypothesis that age-related differences in muscular power production during lower limb multi-joint tasks cannot solely be explained by alterations in leg-extensor muscle strength and tendon stiffness seen with aging. Therefore, the second aim of this study was to determine to what extent leg stiffness  is associated with the average mechanical power output during maximal vertical jumping in young and middle-aged adults with the hypothesis that leg stiffness may be a major factor of the age-related decline in muscular power production during lower limb multi-joint tasks. As it has been shown that the mechanical properties of the TS MTU in particular are crucial for lower limb multi-joint tasks  and 26 younger (18–30 years) physically active healthy male adults gave their written informed consent to participate in this study. Participants were included when two participants, one from the young and one from the middle-aged groups had similar TS MTU mechanical properties. Finally, eight middle-aged (range: 41–67 years) and eight younger (19–28 years) adults were matched for TS muscle strength and tendon stiffness. None of the participants had experience in regularly performing DJs. Exclusion criteria were any previous Achilles tendon ruptures, Achilles tendon injuries  or pain within the last 12 months, or musculoskeletal impairments in the lower limbs , which could have influenced the outcomes of this investigation. The study was approved by the university’s human ethics committee and was conducted according to the Declaration of Helsinki.TMOne, Esaote, Genua, Italy). All sustained contractions were guided by visual feedback displayed on a computer screen showing the produced joint moment. In the current study, force values of ±5% of the target force were accepted (when the force was held for 3 s). If this was not achieved, the specific trial was repeated. During all maximal contractions, strong verbal encouragement was given to the participants in order to attain their actual MVC  onto a force plate  in a randomized order. In order to avoid any effects through muscle fatigue, about 90 s of rest was provided between each trial. Since ground contact time influences leg stiffness during maximal vertical jumping ,b, partimaxF is the maximal vertical ground reaction force and ΔCoM is the maximum vertical displacement of the body’s center of mass during ground contact . The level of statistical significance was set at α = 0.05. All results provided in the text, tables and figures are presented as mean and standard deviation (SD).For all participants, the trial with the greatest jumping height for each jumping condition (box height) was taken into account for further analysis. A two-way repeated measures analysis of variance  was performed in order to detect potential effects of age or box height on DJ height or kinetics with respect to average mechanical power, leg stiffness, maximal vertical ground reaction force and ground contact time. Detected significant main effects or interactions were further analyzed using Duncan’s Figures 2), which meant that there were no significant differences in maximal isometric ankle joint plantar flexion moments and GM tendon stiffness between young  and middle-aged adults (3.2 ± 0.5 Nm/kg and 572 ± 100 N/mm). Paired samples t-tests revealed a significant group difference in age , but no significant differences in body height (178.3 ± 6.5 cm vs. 179.9 ± 4.7 cm) and mass (79.3 ± 9.6 kg vs. 75.3 ± 4.9 kg).The eight young and eight middle-aged adults were matched for TS isometric muscle strength and tendon stiffness  = 3.04, p < 0.05]. Duncan’s post hoc analysis revealed no differences in jumping height between TS muscle strength and stiffness-matched young and middle-aged adults independent of jumping condition . Jumping height was significantly lower for the 13 cm compared to all other box heights in both age groups. However, a lower DJ performance for the 23 cm compared to the 39 cm condition was only found in younger adults.Concerning the DJ performance, the implemented two-way ANOVA revealed a statistically significant age group × box height interaction for jumping height  and maximal vertical ground reaction force during support phase , with the middle-aged adults showing longer ground contact times and lower forces for all box heights . The two-way ANOVA revealed a statistically significant age × box height interaction for average mechanical power . Duncan’s post hoc analysis revealed significant differences in average mechanical power between age groups independent of box height (1.39 ≤ d ≤ 3.16) and higher power values with increasing box height . However, the middle-aged adults showed no significant difference in average mechanical power for the 23 and 33 cm conditions. Further, there was a statistically significant age group × box height interaction for leg stiffness . Duncan’s post hoc analysis revealed lower leg stiffness values in the middle-aged compared to younger adults for all jumping conditions (1.18 ≤ d ≤ 2.57) and lower leg stiffness values with raising box height only in the younger adults . However, no significant difference in leg stiffness was found between the 33 and 39 cm conditions.Considering the DJ kinetics, there were significant age effects on ground contact time [p < 0.001) effect of jumping condition on maximal vertical ground reaction force during support phase [F = 17.23], with higher vertical ground reaction forces with increments in box height. However, no significant difference in maximal vertical ground reaction force could be detected for the 33 and 39 cm conditions. Significant positive correlations were found between average mechanical power and leg stiffness over all analyzed participants .Regarding a potential box height effect on DJ kinetics, there was a significant , meaning that approximately 50 to 70% of the variability in average mechanical power during support phase can be related to the variance in leg stiffness within the pooled group of middle-aged and younger adults. These results support previous findings showing a significant relationship between muscular power output and the stiffness of the lower limb joints during maximal vertical jumping , indicating that leg-extensor isometric muscle strength and tendon stiffness play an important role for the performance in explosive motor tasks . The current finding, that a similar performance during maximal vertical jumping can be achieved by different motor task execution strategies i.e., levels of leg stiffness is in accordance to previous results ,b. In thper se. Despite the fact that seven of our middle-aged adults were between 41 to 59 years, we observed functionally relevant (≥36%) differences for the main outcome parameters between the age groups, indicating that including a higher number of participants over the age of 59 years would have even strengthened the findings of the current study. Finally, a limitation of the current study is the relatively low number of participants in each group  which reduces the potential for detecting statistical differences between age groups. Therefore we cannot exclude that a higher number of subjects might have led to significant differences in jumping height between young and middle-aged adults. However, this drawback has no effect on our observation that matching young and middle-aged adults for TS muscle strength and tendon stiffness does not eliminate age-related differences in mechanical power output during jumping.A limitation of the current study may be that we did not use optical motion capture analysis but used a more convenient approach in order to assess mechanical power during maximal DJs. However, average mechanical power was calculated by the ratio of total work and ground contact time for all age groups and, therefore, we believe that this drawback potentially affects our results more in absolute terms than the validity of the corresponding comparative data. Regarding our ankle-knee joint configuration for GM tendon stiffness assessment, the contribution of the GM muscle to the net joint moment may be reduced compared to a fully extended knee joint angle since the GM operates on the ascending limb of the force-length relationship. However, in a previous study  we foundIn conclusion, independent of task demand, matching younger and middle-aged adults for TS isometric muscle strength and tendon stiffness eliminates age-related differences in jumping performance but not in mechanical power production during maximal DJs. Leg stiffness during the support phase was found to be significantly associated with muscular power production during maximal DJs, with lower leg stiffness values in middle- compared to younger-aged adults. Thus, while jumping performance appears to be unaffected when leg extensor muscle strength and tendon stiffness are maintained, the reduced muscular power output during lower limb multi-joint tasks seen with aging may be due to age-related changes in motor task execution strategy rather than due to muscle weakness.The data supporting the conclusions of this manuscript will be made available by the authors, without undue reservation, to any qualified researcher.This study was carried out in accordance with the recommendations of the German Sport university’s human ethical commitee. The protocol was approved by the German Sport university’s human ethical commitee. All subjects gave written informed consent in accordance with the Declaration of Helsinki.KK, SH, and MK conceived the work. SH, TA, and MK acquired the data. MK drafted the manuscript. All authors contributed to analysis and interpretation of the work, prepared the figures, contributed to final approval of the version to be published, and agreed to be accountable for the work.KK has equity in Protendon GmbH & Co. KG, whose device and software was used for the data collection, processing, and analysis in this study. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The handling Editor declared a shared affiliation, though no other collaboration, with one of the authors CM.


The all-inside cruciate ligament graft preparation technique has become popular due to its utility in sparing a growing physis, preserving a tendon in ACL surgery, and/or reduction of pain. However, few studies have compared graft preparation techniques to determine the ideal construct for cruciate ligament reconstruction. We sought to compare biomechanical properties of two quadrupled all-inside cruciate ligament graft preparation techniques and three alternative all-inside graft preparation techniques that may be used when the available tendon is too short to be quadrupled.n = 10) representing all-inside graft preparation techniques, including two quadrupled  and three alternative methods . Each graft construct underwent preconditioning (10 loading cycles from 20 to 50 N at 0.1 Hz), cyclic loading (500 loading cycles from 50 to 250 N at 1.0 Hz) and load-to-failure (tension applied at 20 mm/min).Fifty porcine extensor tendons were evenly divided into five groups (p = 0.915), cyclic stiffness , pullout stiffness , ultimate failure load , or ultimate failure displacement . The mean cyclic displacement of the Two-Doubled group was significantly greater than the Quad-A , Quad-B , Tripled , and Folded group . There were no other statistically significant differences between the three alternative all-inside graft preparation techniques.Quad-A and Quad-B demonstrated no significant differences in cyclic displacement (10.5 ± 0.3 vs 11.7 ± 0.4 mm; The current study demonstrates the biomechanical properties of two quadrupled all-inside graft constructs, Quad-A and Quad-B, are not significantly different. When the available tendon is of insufficient length, the Two-Doubled group demonstrated more than twice the cyclic displacement of all other graft preparation techniques, and is therefore not recommended for use in all-inside cruciate ligament reconstruction. The all-inside technique is a relatively new approach to anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction that has gained popularity in recent years, in part because of its minimally invasive approach, preservation of cortical bone, and potential sparing of tendon tissue (autograft) or cost  compared to traditional techniques , a tripled construct (Tripled), a folded construct (Folded), and two grafts in doubled form (Two-Doubled) which are illustrated in Fig. o C) porcine extensor tendons, acquired from J & J Packing Co. Inc.  were randomly divided into five groups. Specimens were thawed in a refrigerator within 48 h of use and underwent only one freeze-thaw cycle. Once thawed, the bifurcate tendon was divided, all adherent muscle tissue was removed, and grafts were trimmed to achieve average graft construct lengths of 50–70 mm for all groups  by passing the doubled No. 5 looped-suture in a figure-of-eight pattern around 4 screws which were used to lightly compress aluminum clamps on the suture on both the femoral and tibial ends Fig. .Fig. 2A Load and displacement data were collected at a frequency of 20 Hz during all phases of testing and the testing protocol was executed as previously described by Walsh and colleagues .All outcomes were assessed using generalized estimating equation (GEE) models to compare the differences of the graft types while controlling for the clustered nature of the data. GEE parameter estimates were generated using quasi-likelihood estimation. Post hoc tests were conducted to determine differences between graft types. Reported p > 0.999), tendon width (p = 0.373), graft construct length (p = 0.439), or graft construct width (p > 0.999).The dimensions of the tendons and graft constructs for each of the preparation techniques, prior to testing, are reported in Table p < 0.001). There were no statistically significant differences (p > 0.05) between the individual tendon widths of the Tripled, Folded and Two-Doubled groups. The graft construct length of the Tripled vs Folded groups was not significantly different (p > 0.999), nor was the difference between the Tripled vs Two-Doubled groups (p = 0.132). There was a statistically significant difference between the Folded vs Two-Doubled group , however. The final graft construct widths, prior to testing, demonstrated statistically significant differences in the Tripled vs Folded (1p = 0.004), Tripled vs Two-Doubled (1p = 0.010) and Folded vs Two-Doubled (p < 0.001) group comparisons.After being trimmed to achieve final graft construct lengths of 50–70 mm, the tendon lengths of the Tripled (196.3 mm), Folded (148.5 mm) and Two-Doubled group (115.5 mm) demonstrated significant differences when compared to one another (p = 0.915), cyclic stiffness (p = 0.290), pullout stiffness (p = 0.443), ultimate failure load (p = 0.672), or ultimate failure displacement (p = 0.778). When compared to the Tripled group, the Quad-A group demonstrated significantly greater ultimate failure load (p = 0.046) and less ultimate failure displacement (p = 0.010). The post hoc pairwise comparisons for each of the biomechanical parameters are organized in Table The biomechanical parameter estimates of each of the graft preparation techniques are reported in Table ss p = 0.43, ultimp < 0.001), Quad-B group (p < 0.001), Tripled group (p < 0.001), and Folded group (p < 0.001). No other statistically significant differences were observed between the groups. However, the pullout stiffness of the Quad-A group was nearly statistically significantly greater than the Tripled group (p = 0.059).The mechanisms of failure of the various graft types were also observed. No slipping of the suspensory suture at the clamp-suture junction was observed, nor was stretching of the Fiberwire suture. Quad-A and Quad-B grafts failed when the whipstitched free end of the graft pulled from its tibial end and through the nearest cerclage suture, elongating the graft significantly. The Tripled group showed a similar mechanism of failure as the free, whipstitched ends at the femoral and tibial sides of the graft pulled through the cerclage sutures.The mean cyclic displacement of the Two-Doubled group was the largest amongst all groups, and was significantly greater than the Quad-A group  encountered during early rehabilitation protocols following ACL and PCL reconstruction (Shelburne et al., Importantly, our results indicate that the least robust portion of an all-inside graft construct is the suture used to secure it and/or suspend it. This is in contrast to other graft preparation techniques, in which the graft itself is the first to fail when tested in a biomechanical environment. The all-inside graft preparation technique seems to transfer the loads from the fixation itself to the whipstitch.At present, the literature remains unclear on which graft preparation technique should be used if the tendon is of insufficient length to produce a quadrupled graft. In the current study, we compared three alternative methods of graft preparation to the quadrupled techniques to evaluate their relative biomechanical strength. During cyclic loading, cyclic displacement of the Two-Doubled group was greater than twice that of every other group, which makes this technique the least appealing option for all-inside ACL and PCL reconstruction. Although not statistically significant, due likely to the high variability of the Qual-A and Quad-B groups relative to the other groups, the Tripled technique demonstrated the least amount of cyclic displacement of the three alternative methods. Thus the Tripled group may be the preferred technique to employ if the tendon is of insufficient length to be quadrupled. However, further research is needed to clarify if this is truly the case. The Tripled group failed at significantly lower ultimate failure loads when compared to the Quad-A group, but not the Quad-B group; a significance that was lost in the Folded and Two-Doubled groups as a result of higher variability. Ultimate failure displacement was also significantly greater in the Tripled group compared to the Quad-A group; however, this parameter has less clinical significance due to the anatomical limitations of the knee joint itself.While the ultimate failure displacement in the Two-Doubled group did not differ significantly, the variability of this group was relatively high when compared to the Tripled and Folded groups. This appeared to be due to failure of the suture material at the tibial end of the graft where the free ends were whipstitched together, and this whipstitch was utilized to incorporate the suspensory suture. This may indicate that wrapping the tendon itself, rather than suture, around the suspensory device lends inherent strength to the graft construct. Therefore, we question the integrity of graft preparation in single tendon, non-folded constructs such as quadriceps tendon mounted on a suspensory device via suture alone on the both the femoral and tibial ends (Slone et al., Ensuring that various graft fixation methods are sufficient to withstand the forces experienced during early post-operative rehabilitation has been an active area of research in recent years. Fortunately, biomechanical studies have demonstrated that many suspensory devices have sufficient strength to withstand forces that exceed even the highest loads experienced during early exercise protocols (Bartz et al., Johnson et al. demonstrated that modern cortical suspension devices are capable of withstanding ultimate forces of 784–2231 N (Johnson et al., Fabbri et al. used a similar model to evaluate whether graft length is critical for success in all-inside reconstruction, including a quadrupled model similar to Quad-A in our study, as well as a tripled model similar to that in our study, and a half-quadrupled model that was unique to their study (Fabbri et al., Mayr et al. compared several all-inside graft preparation techniques with varying degrees of suture fixation (Mayr et al., Barbosa et al. described an alternative technique which minimizes suture in the bony socket, proposing that suture wrapping the tendon in the bony socket reduces the bone-tendon contact area crucial for biologic integration of the graft (Barbosa et al., Our study is not without its limitations. First, a study of porcine tendons cannot be directly compared with studies using human tissue, although our graft preparation technique was equivalent to the clinical setting. Porcine tendon specimens have been reported to have similar properties to human tendons in previous biomechanical studies (Yamanaka et al., Another limitation is that this study was designed to test the relative biomechanical properties of different graft preparation techniques in isolation, which does not provide information about the graft and fixation device interaction or complex as an entire unit. Additionally, the testing protocol provides information about the relative displacement, stiffness and load tolerance in a linear fashion, which limits us from making inferences based upon the external forces and dynamic vectors that are placed upon the ACL or PCL graft as it occurs in vivo. Further research is necessary to investigate the biomechanical properties of the entire graft constructs with various fixation devices in vitro in addition to appropriate prospective studies designed to identify clinically relevant outcomes in the long term.The two quadrupled techniques for all-inside cruciate ligament reconstruction demonstrated no significant difference in any of the primary endpoints measured, suggesting that either technique could be the preferred method for all-inside ACL and PCL reconstruction. The Tripled technique is preferred if a graft is of insufficient length for quadrupled preparation. The Two-Doubled technique was observed to have greater than twice the cyclic displacement of every other preparation technique tested, and is therefore not recommended for use in all-inside cruciate ligament reconstruction.


Many clinical libraries offer a journal alerting service that gives clinicians the opportunity to review the most current tables of contents for journals of interest. Benefits of this service include helping clinicians keep up to date with their specific areas of clinical practice or research; increasing usage and awareness of expensive journal subscriptions; cross-promoting other library resources, services, and news; regularly reminding clinicians that the library exists and is available to provide other services; and improving customer satisfaction –3.Mechanisms for providing a journal alerting service have evolved over the years, moving from simple paper-based approaches to electronic tables of contents (e-TOCs) services. As the number of potential e-TOCs increases, it becomes increasingly unwieldly to register and sign up for alerts with multiple publishers. JournalTOCs circumvents this issue by aggregating e-TOCs so that they are available from one online resource.JournalTOCs is a portal provided by Heriot-Watt University , 5. AlerThe free version of JournalTOCs allows users to sign up for 30 journal alerts. This review, however, focuses on JournalTOCs Premium, which allows clinical libraries to provide a comprehensive email journal alerting service for clients, with features such as 300 journal alerts per user, customized library messages in alert emails, and integration with an institution’s journal subscriptions for full-text access. Given this use case, the experience with JournalTOCs Premium will be described from the perspective of both the end user and the institution.Take a random client . He has received a message from his library that they have subscribed to JournalTOCs Premium. Stu registers with his institutional email address, as this makes his institution’s subscribed journal collection available to him. Stu can find journals of interest by browsing subjects, browsing publishers, or searching and then selecting journals to “follow” .On the JournalTOCs Home page, he can see his journals and their access levels: a green square for journals that his institution subscribes to, a green OA for open access journals, a divided green/red box for journals having some open access articles, and a lock icon for journals that are not directly accessible to him. Stu will now start receiving emails with new journal content and can update his selections at any time.When an institution subscribes to JournalTOCs Premium, the first step is to upload a list of its subscribed journals. The list must be in .csv format with a maximum of 2,000 records per upload, so multiple uploads may be required.The Service Configuration section has numerous settings, organized by category. The Look and Feel section settings include welcome text, library email and website details, and a logo that clients will see on the JournalTOCs home page. A reference manager format  can be specified here. In the Full Text Access section, access can be configured by OpenURL, EZProxy, and Internet protocol (IP) range. There are also options for allowing proxied uniform resource locators (URLs) in alerts and including a Request a Copy link in emails. The Email Alert section allows users to specify that alerts are sent journal by journal (rather than as a digest), with various additional options relating to frequency, link structure, and email appearance. The Email Templates section enables customization of various emails , including header and footer images (Logos tab) and text (including HTML links). Templates are easy to update and provide a very convenient channel for alerting clients to new library resources and services.JournalTOCs Premium allows a variety of e-TOC alert options, which can be patron driven, library driven, or somewhere in between. In the latter option for example, library staff could add or remove e-TOC subscriptions for an existing client account. This feature allows flexibility, as not all clients are comfortable setting up alerts themselves. An additional example of a hybrid approach is that library staff can set up a single journal alert for all new staff, after which users can either add or remove alerts depending on their preferences.JournalTOCs Premium offers an application programming interface (API) consisting of four calls . Some sites have used the API to enable e-TOC subscriptions from their own discovery systems. Note that this integration requires liaison with the vendor.Usage Reports are available for metrics that include journals followed and clients and their e-TOC subscriptions. Figures for article titles clicked (as a proxy for full-text articles for subscribed content) or Request a Copy links clicked are not available, unfortunately; these would be very useful in evaluating impact.JournalTOCs is currently in the process of adding a Request Article link at the article level for all alerts, which will strengthen its value to clients and subscribing libraries.A number of apps provide alerts for clinical content, including BrowZine , Read 77, and DoJournalTOCS is probably the closest to a traditional new journal issue alert. Technically, BrowZine is not an alerting service at all; clients must remember to return to the app or site to view new content. This reviewer has had the experience of signing up for similar services only to forget about them completely and then one day return to the services to find thousands of new items. An alerting capability is on the BrowZine development roadmap , and if Perhaps the most powerful advantage of JournalTOCs is the ability to deliver customized messages and links regularly into clients’ inboxes. Libraries can easily update this messaging feature to cross-promote other library resources and services. More generally, the steady flow of emails to clients serves as a reminder that the library exists and is available to assist in other areas besides journal alerts.JournalTOCs, BrowZine, Read, and Docphin all have browser-based interfaces. The latter three also have apps, and this is frequently the channel by which they are promoted. In some ways, it seems curious to suggest that only having a browser version is an advantage. However, browsers accessed via a computer and email are near universal for health services staff, so there is less of a technology barrier than with mobile alternatives.This review has explored JournalTOCs Premium, which is a subscription product. The website specifies, “The price of an annual licence starts at £480.00 GBP and is in proportion to the number of journals, the estimated number of user accounts, the amount of tailored unique features requested for the customization and the type of your organisation (e.g. non-for-profit institutions)” . This woWith the ever-growing amount of information, clients can often be overwhelmed when their searches return very large numbers of search results, whether via a web search engine or the library’s discovery system. In contrast, journal content alerts provide a neatly packaged set of results with a manageable number of items focused on a journal’s specific subject area. Several vendors seem to recognize this advantage and have products existing or in development that will compete with JournalTOCs. A noteworthy example is Ovid, which is in the process of introducing its discovery product (Ovid Discovery), which includes e-TOCs for approximately 16,000 journals via its Journals listing interface. Not surprisingly, the journal alerts space has matured over time. Libraries now have a number of sophisticated options available to them to help their clients stay up to date and, in the process, help promote the library service.


Osteochondral grafts are used clinically to repair cartilage and bone defects and to restore the congruent articulating surfaces of the knee joint following cartilage damage or injury. The clinical success of such osteochondral grafts is heavily reliant on the biomechanical and tribological properties of the surgical repair; however, a limited number of studies have investigated these factors. The aim of this study was to evaluate the influence of graft harvesting and implantation technique as well as bone properties on the primary stability of press-fit implanted osteochondral grafts using a series of uniaxial experimental push-in and push-out tests. Animal (porcine and bovine) knees were used to deliver models of different bone properties (elastic modulus and yield stress). The study showed the graft harvesting method using either a chisel or drill-aided trephine to have no influence on primary graft stability; however, the preparation technique for the graft recipient site was shown to influence the force required to push the graft into the host tissue. For example, when the length of the graft was equal to the recipient site (bottomed), the graft was more stable and dilation of the recipient site was shown to reduce short-term graft stability especially in immature or less dense bone tissue. The push-out tests which compared tissue of different skeletal maturities demonstrated that the maturity of both the graft and host bone tissue to influence the stability of the graft. A higher force was required to push out more skeletally mature grafts from mature bone tissue. The study demonstrates the importance of surgical technique and bone quality/properties on the primary stability and ultimately, the success of osteochondral grafts in the knee. For patients with isolated chondral lesions with no additional comorbidities of the joint, there are a number treatments which may be adopted that aim to restore the congruent articulating surfaces. These include microfracture which stimulates fibrous tissue repair, transplantation of either autologous or allogeneic osteochondral grafts or cell-based approaches such as autologous chondrocyte implantation (ACI)/matrix-induced autologous chondrocyte implantation (MACI).4 Where there is extensive cartilage degeneration, total or partial joint replacement may be more appropriate.6Osteoarthritis affects more than 8 million people in the United Kingdom with the knee being the most commonly afflicted joint.8 which often leads to tissue damage. Osteochondral grafts implanted flush to the cartilage surface can be used to reconstruct the articulating surface which can restore the contact pressure and area of the natural joint surface.810 The clinical application of osteochondral grafts in the knee involves implantation of either single or multiple (mosaicplasty) autologous or allogeneic grafts into osteochondral defects to restore the articular surface.5 The advantage of osteochondral grafting over microfracture or cell-based therapies is the immediate restoration of the articulating surfaces of the joint.4 However, a number of factors limit the clinical use of osteochondral grafts. These include tissue availability, donor site morbidity, disparity in congruency between the graft and host and lack of integration between the graft and host tissue.4 Despite the clinical adoption of biological interventions such as osteochondral grafting especially in young patients for whom a joint replacement may not be appropriate, a limited number of studies have been carried out to investigate the mechanical stability and tribological performance of these grafts.12 The success of osteochondral grafting in restoring the biomechanics and biotribology of the joint has been shown to depend on the restoration of the articulating surfaces.11 This study focuses on how variations in surgical technique and bone properties influence the primary stability of the graft prior to integration between the graft and host tissue.The presence of a focal defect in the cartilage surface may cause high contact stresses13 The more commonly used chisel method involves driving the tubular chisel into the tissue perpendicular to the cartilage surface using a hammer to a depth of ∼15 mm. The corer is then toggled to break the osteochondral plug which can then be removed and ejected from the corer.1416 When preparing the recipient site, first, the recipient site is drilled, then for the surgical kit used, it is a standard practice to use a conical dilator to compact the surrounding subchondral bone, and slightly widen the recipient hole at the articular surface.1519 The influence of dilation of the recipient site was investigated as well as the depth of the recipient site in relation to the length of the graft. This investigation was carried out using grafts implanted in the femur of porcine and bovine tissues as opposed to human tissue. The use of animal tissue has advantages including, greater consistency between tissue samples which reduces biological variability, availability of tissue and different animal species of varying skeletal maturities give models of varying bone properties such as yield stress and elastic modulus which allows different bone characteristics to be investigated.21 The porcine tissue, from relatively young animals where the bone mineral density (BMD) is still increasing23 represented bone with an elastic modulus and yield stress at the lower limit of that of patients who would potentially undergo osteochondral grafting as a treatment for focal osteochondral lesions; the bovine tissue with a higher elastic modulus and ultimate strength, potentially exceeding that of human bone2426 represented tissue from more skeletally mature patients with a higher BMD.The surgical techniques considered were the method for harvesting the graft and the preparation of the defect site. There are two commonly used methods for harvesting graft tissue either using a tubular chisel or a drill-aided trephine . The treThe aim of the study was to assess the mechanical stability of osteochondral grafts using a series of experimental uniaxial push-in and push-out tests investigating different parameters associated with the surgical technique used for graft harvesting and implantation, and bone properties. The study aimed to address the following research questions: (1) Does the method of harvesting the graft either using a drill-aided trephine or a chisel influence the initial graft stability? (2) Does the preparation of the recipient site for the graft influence the initial graft stability? in terms of (a) the depth of the recipient site in relation to the graft length and (b) the use of dilation of the recipient site? (3) How do bone properties of the graft and/or host tissue influence graft stability?21 All tissues were sourced from a local abattoir supplying the food trade. Tissue samples were kept hydrated throughout the preparation procedures using phosphate buffered saline  and stored until required for testing in PBS-soaked tissue paper at −20 °C. Samples were removed from storage prior to testing and thawed at room temperature.Skeletally mature bovine femurs from 18- to 24-month animals and 4- to 6-month skeletally immature porcine femurs with intact femoral condyles were used in this study to deliver models of different bone properties such as yield stress and elastic modulus.The aim of the push-in test was to determine the force required to push a single osteochondral graft below congruency. Femurs (bovine or porcine) were cemented into a jig which allowed the inclination angle of the bone to be adjusted. Grafts of 6.5 mm (bovine or porcine) or 8.5 mm (bovine) in diameter and 10 mm in length were taken from the weight-bearing regions of the femoral condyles using the Acufex™ Mosaicplasty surgical kit using either a hammer and chisel or drilled using a trephine according to the manufacturer’s guidelines. Grafts were implanted into the weight-bearing regions of the medial femoral condyles. The recipient hole was prepared to a known depth using the drill, dilator and tamp from the Acufex™ Mosaicplasty surgical kit. The graft was then inserted into the recipient site flush with surrounding cartilage. Four grafts were positioned in each bovine femur and three in each porcine femoral condyle. Throughout the tests, the surface of the cartilage was kept hydrated with PBS.27 and Lowery,28 as shown in The test method used was adapted from previous work by Kock et al.n = 5 was carried out for each experimental group and the uneven sample sizes were due to failed samples. A test was considered to have failed if one of the following occurred: 4 mm below congruency was not achieved, if the indenter did not remain perpendicular to the surface of the graft or if the indenter contacted the side walls of the recipient hole. For each test, the diameter of the graft used, the depth of the recipient site and the type of tissue were based on the research question to be answered.The experimental groups are shown in Fmax) was measured. The experimental groups are described in The aim of the push-out test was to determine the force required to displace an osteochondral graft from within the host tissue immediately after implantation. Grafts were inserted into recipient holes positioned flush to the cartilage surface in the weight-bearing region of the medial femoral condyle, as described for the push-in tests. The distal part of the condyle was then cut away from the rest of the femur at the level of the base of the grafts. This allowed the base of the grafts to be accessed. The section of bone with the grafts was placed cartilage-side down on a hollow support fixture which allowed the graft to be pushed out of the host bone tissue without interference from the fixture. A 5-mm indenter was attached to the Instron materials testing machine which was used to push the graft from its base out of the back of the tissue using a rate of 1 mm/min . The maxp < 0.05.For the push-in tests, the mean load ± 95% confidence limits was calculated for each experimental group at 0.25 mm displacement intervals. For the push-out tests, the maximum mean push-out force ± 95% confidence limits was calculated. Statistical analysis was carried out using one-way analysis of variance (ANOVA) with a post hoc Tukey’s test in SPSS. The experimental groups investigated for each research question were compared. For clarity, in the push-in tests, this was carried out at 0.25 mm displacement intervals. Significance was taken at 29The data associated with this article are openly available from the University of Leeds data repository.p > 0.05) at any level of displacement below congruency in the force required to displace bottomed 6.5-mm-diameter grafts harvested from bovine tissue using either a chisel or a trephine  compared with unbottomed grafts at all levels of displacement greater than 1.5 mm. For the bottomed grafts, from 1 to 4 mm below congruency, there was a linear rate of increase in the force required to displace the grafts.The load–displacement curves for bottomed grafts, those for which the length of the graft was equal to the depth of the recipient site and unbottomed grafts, for which the recipient site was deeper than the length of the graft, were markedly different . For unbFor porcine tissue, when the recipient site was dilated, there was a poor fit between the graft and the recipient site resulting in a fissure between the edge of the recipient site and the graft . Withoutp < 0.05) than for either the xenograft or porcine allograft groups. There was no significant difference (p > 0.05) between the xenograft and porcine allograft groups  and porcine allografts, respectively . The maxt groups .12 conditions in the joint, potentially resulting in the onset of degenerative changes or the formation of tissue which is biomechanically and histologically inferior to native articular cartilage.31 This study investigated whether surgical technique or bone properties, would influence the force required to displace the graft in the host tissue.One of the key factors in determining the success of osteochondral graft surgery is the restoration of the congruent articular surface of the cartilage. The aim of this study was to investigate the primary stability of the graft immediately post surgery, prior to tissue integration. Grafts which protrude above or subside below congruency level following implantation, may induce inferior biomechanical and tribological32 previously reported similar findings whereby using a chisel method was shown to cause less cartilage damage than drilling the graft and Vizesi et al.33 showed superior healing response of defects created using a punch rather than a drill. Robert16 in his description of surgical technique with the single-use OATS® instrumentation from Arthrex suggests the donor graft should be extracted using a mallet, never a drill. The design of the cutting edge of the chisel has also been shown to influence tissue damage and cell viability in neighbouring tissue.34 These studies combined suggest that while the harvesting method may not influence the stability of osteochondral grafts in situ, the potential for the method used to damage tissue and influence the long-term healing and success of the graft should be considered.The first variable to be considered was the surgical technique for harvesting grafts. The surgical kit used (Acufex™) gives two methods for extracting grafts, either hammering a tubular chisel into the tissue or using a drill-aided trephine. The trephine method is optional for hard tissue. The primary stability of osteochondral grafts harvested using the different methods has not previously been investigated, and this study showed there was no significant difference in the push-in forces required to displace grafts harvested using either a corer or trephine. However, using the drill method, in some samples, the cartilage either on the graft surface or surrounding the donor site was visibly damaged. Evans et al.36 The force required to displace the graft 4 mm below congruency was approximately three times higher in bottomed grafts compared with unbottomed grafts; this difference in magnitude force is similar to that measured by Kordás et al.35 in a cadaveric knee study. These results show the importance of the graft length being equal to that of the recipient site for primary graft stability.The surgical technique for graft implantation was also investigated. First, the influence of graft length compared with the depth of the recipient hole was considered. The load–displacement curves for unbottomed grafts where the recipient site was deeper than the graft length and bottomed grafts where the graft length was equal to the recipient site were noticeably different. For unbottomed grafts, the load–displacement curves showed an initial increase in load per unit of displacement over the first 1.5 mm of motion when, to initiate graft movement, the graft–host interference force must be overcome. Once the graft began to move, the force required for the graft to continue descending into the recipient site was constant resulting in a plateau in the load–displacement curve. The bottomed grafts were supported by the underlying trabecular bone, therefore, when subjected to a push-in test, they underwent confined compression resulting in a much steeper and prolonged increase in load per unit of displacement compared with the unbottomed grafts. The higher push-in force of bottomed grafts compared with unbottomed grafts is consistent with previously published research.p < 0.001) push-in force to overcome the static friction between the graft and host than when dilation was used. When measured, the diameter of the drill bit was 6.35 mm and the dilator 6.80 mm showing the extent to which dilation enlarged the recipient site. Kordás et al.37 investigated the influence of dilation and showed greater graft stability with a shorter dilation length. In the porcine model, a shorter dilation length would have still resulted in a mismatch at the articulating surface, dilation was used on all bovine tissue samples and the discrepancy between the graft edge and the recipient site was not seen in this more mature tissue.The preparation of the recipient site was also investigated in terms of the use of dilation of the host site. With the Acufex™ Mosaicplasty surgical toolkit, dilation of the recipient site is standard procedure; however, the influence of recipient site dilation on the primary stability of osteochondral grafts implanted in tissue with different bone properties has not previously been considered. For this study, porcine tissue was used from younger, less skeletally mature animals compared with the bovine tissue used to answer the other research questions. During sample preparation, it became apparent that dilation resulted in recipient holes which appeared larger than the 6.5-mm-diameter graft and in many samples this led to a poor fit between the graft and host tissue. Grafts inserted without the use of dilation required a significantly higher  for grafts of similar geometry. The push-out forces were lower when porcine tissue was used for either the graft or recipient site compared with a bovine-in-bovine model. The increased force required to push out the bovine grafts was attributed to the skeletal maturity of the samples, likely higher bone mineral density and higher modulus of the more mature bovine bone compared with the more skeletally immature bone and lower modulus of the porcine samples.2022 These results highlight the importance of the maturity and quality of the underlying bone to achieve initial stability of the graft.In the push-out study, the maximum forces measured for porcine grafts in porcine recipient sites (50 ± 36 N) were comparable with pull-out forces measured in previous studies by Duchow et al.37 however, the use of multiple grafts may better restore the geometry of the articulating surfaces. The test method applied a constant displacement rate which did not replicate the complicated loading and motion profiles experienced by the joint in vivo. For this study, healthy animal tissue was selected rather than human tissue to control bone properties, reduce biological variability and for tissue availability; however, this approach gave no consideration to potential disease or degeneration of the cartilage or underlying bone. Using animal tissue from different sources allowed the functional stability of osteochondral grafts in tissue of different moduli, to start to be investigated. The porcine tissue from relatively young, skeletally immature animals23 represented bone with an elastic modulus and yield stress at the lower limit of that of patients who may undergo osteochondral grafting as treatment for focal osteochondral lesions; the skeletally mature bovine tissue with a higher elastic modulus and ultimate strength, potentially exceeding that of human bone2426 represented tissue patients with a higher BMD. This study therefore shows that the quality and properties of the host and recipient tissue influence the clinical outcome; however, future work is necessary to determine the applicability of the animal models to human tissue. Furthermore, this study shows the importance of considering the properties of any synthetic or decellularised osteochondral scaffold combined with the properties of the host tissue on the resulting stability. Finally, the study considered only the initial stability of the grafts following implantation, within the first approximately 4 weeks following implantation, the stability of the graft is reliant on the press-fit mechanism,19 after this time period, bone remodelling starts to give the graft additional stability. Therefore, although longer term integration of the graft and host tissue has not been considered in this study, both the primary press-fit stability and the longer term integration of bone tissue influence the success of the treatment.There were a number of limitations associated with this study, first, only a single graft was used, often in larger defects, multiple grafts are introduced (mosaicplasty). Single grafts have been shown to be more stable than multiple grafts due to the larger contact area between the graft and host tissue;Understanding factors which influence the initial stability of osteochondral grafts is important for the longer term restoration of the congruent articulating surfaces and the success of the osteochondral graft. This study highlights the importance of surgical technique on the initial biomechanical stability of osteochondral grafts. The push-in forces were higher suggesting that the graft would be more stable when the length of the graft was equal to the depth of the recipient hole (bottomed grafts) and bone tissue was more mature. In terms of graft stability, the method for harvesting the graft did not influence the push-in force; however, dilation of the host tissue was shown to influence the interference fit between graft and host in lower modulus bone.