PMC:5494313 / 13529-19731 JSONTXT

{"target":"http://pubannotation.org/docs/sourcedb/PMC/sourceid/5494313","sourcedb":"PMC","sourceid":"5494313","source_url":"https://www.ncbi.nlm.nih.gov/pmc/5494313","text":"RESULTS\nFE-SEM images of the SLA and modSLA Ti surfaces revealed honeycomb-shaped irregularities that were the result of the sandblasting and acid-etching procedures (Figure 2). These are typical features of these surfaces. FE-SEM images of the Ti tube surface revealed machining grooves, which is characteristic of the computer numerical control milling process that was used to manufacture these tubes. The EDS results of the SLA and modSLA surfaces were similar, indicating that they were mainly composed of Ti and oxide. By contrast, the Ti tube consisted of 97.7% Ti.\nFigure 2 FE-SEM of the modSLA and SLA implants and the Ti tube. (A and B) FE-SEM images of the modSLA (A) and SLA (B) surfaces. Both implant types had been blasted with large-grit sand and acid-etched. The modSLA implant was further modified by being rinsed under nitrogen protection and then sealed in glass tubes containing isotonic NaCl. This procedure was conducted to increase the hydrophilicity of the implant. The surfaces exhibited similar micro-topographical features. The procedure intended to increase hydrophilicity had little effect on the modSLA surface topography. (C) FE-SEM images of the Ti tube. The left image shows a machined surface consisting of grade 4 commercially pure Ti. The right image shows a magnification of the left-hand FE-SEM image. It depicts many machined grooves that were etched by computer numerical control milling (white arrowheads). The bars in the left (A, B, C) and right (C) images indicate 20 μm, 20 μm, 1 mm, and 20 μm, respectively.\nFE-SEM: field emission scanning electron microscopy, modSLA: modified sandblasted and acid-etched, SLA: sandblasted and acid-etched, Ti: titanium, NaCl: sodium chloride. After in vivo surgery, none of the rabbits exhibited complications in terms of wound healing, implant exposure, or other problems. Histological analyses showed that, 4 weeks after implantation in the absence of Ti tubes, the SLA and modSLA surfaces exhibited excellent osseointegration (Figure 3A and C); in other words, sufficient bone formation was observed around the implants. By contrast, when the Ti tubes were applied, very little bone formed between the implant and the inner surface of the Ti tube. However, mature bone was observed on the outer surfaces of the Ti tubes. This was observed for both the SLA and modSLA implants (Figure 3B and D).\nFigure 3 Light microscopic histological views of the modSLA and SLA implants with and without the Ti tube. Both implant types had been blasted with large-grit sand and acid-etched. The modSLA implant was further modified by being rinsed under nitrogen protection and then sealed in glass tubes containing isotonic NaCl. (A) modSLA without Ti tube. (B) modSLA with Ti tube. (C) SLA without Ti tube. (D) SLA with Ti tube. The red boxes indicate the area on the image that was further magnified on the right. The modSLA and SLA implants without Ti tubes showed good formation of cortical bone; Haversian systems (red arrowheads) are visible around the surfaces of both implants (A and C). By contrast, the modSLA and SLA implants with Ti tubes (blue arrowheads) exhibited little or no bone on their surfaces (B and D). Note that the implant surfaces in (A) and (C) were adjacent to a solid wall of bone. By contrast, the spaces between the implants and Ti tubes in (B) and (D) were empty, which indicates a lack of osteogenesis. In (A-D), the bars in the left, middle, and right images indicate 1,000 μm, 500 μm, and 50 μm, respectively (H\u0026E).\nmodSLA: modified sandblasted and acid-etched, SLA: sandblasted and acid-etched, Ti: titanium, NaCl: sodium chloride, H\u0026E: hematoxylin and eosin. The modSLA implants had significantly lower BIC ratios than the SLA control implants, regardless of whether a Ti tubes was present or absent (P=0.043). Moreover, the implants within Ti tubes had significantly lower BIC ratios than the implants not placed in Ti tubes, regardless of whether the implants were SLA or modSLA implants (P\u003c0.001) (Table 1, Figure 4).\nTable 1 BIC ratios of modSLA and SLA implant surfaces after implantation with or without Ti tubes The values are presented as mean±standard deviation.\nBIC: bone-to-implant contact, modSLA: modified sandblasted and acid-etched, SLA: sandblasted and acid-etched, Ti: titanium.\nFigure 4 Box-plot analysis of the BIC ratios of each group. In terms of BIC ratios, the SLA surface was more biocompatible than the modSLA surface. However, this difference between the surface types was only marginally significant (i.e., the P values were close to 0.05). Notably, the Ti tubes slowed bone formation considerably regardless of the type of surface.\nBIC: bone-to-implant contact, modSLA: modified sandblasted and acid-etched, SLA: sandblasted and acid-etched, Ti: titanium.\na)P\u003c0.050, b) P\u003c0.010. Immunohistochemistry of the tibial bone around the implants 10 days after modSLA and SLA implantation without Ti tubes showed that BMP-2 was mainly present at the bone-implant interface (Figure 5). Moreover, the BMP-2-expressing areas corresponded with the areas that had new bone formation (as determined using Masson trichrome staining) (Figure 5B).\nFigure 5 Immunohistochemistry of the tibial bone 10 days after implants were placed. Modified modSLA and SLA implants were placed in the tibiae of a rabbit. Ten days after surgery, the rabbit was sacrificed, the implants were removed, and tibial bone sections were generated. (A) The sections were stained for BMP-2 expression. BMP-2 staining is shown by the dark brown areas. Note the marked expression of BMP-2 (red arrowheads) at the bone-implant interface. This suggests that BMP-2 produced by old bone may initiate contact osteogenesis. (B) Other bone sections were stained with Masson trichrome to identify areas of new bone formation (blue color, black arrowheads) along the bone-implant interface. These areas correspond to the area of strong BMP-2 expression in (A). The red rectangular areas shown in the left-hand images (bar=1,000 μm) were magnified further in the right-hand images (bar=50 μm).\nmodSLA: modified sandblasted and acid-etched, SLA: sandblasted and acid-etched, BMP: bone morphogenetic protein.\n\nD","divisions":[{"label":"Title","span":{"begin":0,"end":7}},{"label":"Figure caption","span":{"begin":573,"end":1726}},{"label":"Figure caption","span":{"begin":2382,"end":3670}},{"label":"Table caption","span":{"begin":4033,"end":4312}},{"label":"Title","span":{"begin":4042,"end":4131}},{"label":"Figure caption","span":{"begin":4312,"end":4825}},{"label":"Figure caption","span":{"begin":5178,"end":6201}}],"tracks":[]}