Reconstruction of orbital floor fracture using solvent-preserved bone graft

The orbital floor is one of the most frequently damaged parts of the maxillofacial skeleton during facial trauma. Unfavorable aesthetic and functional outcomes are frequent when it is treated inadequately. The treatment consists of spanning the floor defect with a material that can provide structural support and restore the orbital volume. This material should also be biocompatible with the surrounding tissues and easily reshaped to fit the orbital floor. Although various autografts or synthetic materials have been used, there is still no consensus on the ideal reconstruction method of orbital floor defects. This study evaluated the applicability of solvent-preserved cadaveric cranial bone graft and its preliminary results in the reconstruction of the orbital floor fractures. Twenty-five orbital floor fractures of 21 patients who underwent surgical repair with cadaveric bone graft during a 2-year period were included in this study. Pure blowout fractures were determined in nine patients, whereas 12 patients had other accompanying maxillofacial fractures. Of the 21 patients, 14 had clinically evident diplopia (66.7 percent), 12 of them had enophthalmos (57.1 percent), and two of them had gaze restriction preoperatively. Reconstruction of the floor of the orbit was performed following either the subciliary or the transconjunctival approach. A cranial allograft was placed over the defect after sufficient exposure. The mean follow-up period was 9 months. Postoperative diplopia, enophthalmos, eye motility, cosmetic appearance, and complications were documented. None of the patients had any evidence of diplopia, limited eye movement, inflammatory reactions in soft tissues, infection, or graft extrusion in the postoperative period. Providing sufficient orbital volume, no graft resorption was detected in computed tomography scan controls. None of the implants required removal for any reason. Enophthalmos was seen in one patient, and temporary scleral show lasting up to 3 to 6 weeks was detected in another three patients. Satisfactory cosmetic results were obtained in all patients. This study showed that solvent-preserved bone, which is a nonsynthetic, human-originated, processed bioimplant, can be safely used in orbital floor repair and can be considered as another reliable treatment alternative.     

Applications of a new carbonated calcium phosphate bone cement: early experience in pediatric and adult craniofacial reconstruction

Hydroxyapatite cements have recently been employed as bone substitutes in craniofacial reconstruction. They are easily applied, nonresorbable, available in unlimited quantity, and eliminate donor-site morbidity. Norian CRS (craniofacial repair system) is a new carbonated calcium phosphate paste that is unique in that it more closely resembles bone than do traditional hydroxyapatite pastes. Norian is a low-order crystalline apatite soluble at a low pH, facilitating its resorption and replacement by host bone. The cement was first used for craniofacial surgery in North America at the Children's Hospital of Philadelphia. This report presents the authors' experience with this bone substitute in both pediatric and adult craniofacial reconstruction. Sixteen adult and pediatric patients underwent craniofacial reconstruction involving the use of carbonated calcium phosphate paste for correction of defects that required from 5 to 110 g of carbonated calcium phosphate paste (mean, 28.5 g). The patients were all followed for a minimum of 14 months. Minor complications included one case of infection and two cases involving cement microfragmentation. In the authors' experience, carbonated calcium phosphate paste has proved to be an excellent alloplastic material for osseous augmentation and reconstruction in the craniofacial skeleton. Few problems were encountered using this material; no significant morbidity was encountered. Although this material seems to be promising as a bone substitute, further follow-up will be necessary to evaluate its potential role in craniofacial surgery.     

Differentiation of osteoblasts on pectin-coated titanium

The gold standard for implant metals is titanium, and coatings such as collagen-I, RGD-peptide, chondroitin sulfate, and calcium phosphate have been used to modify its biocompatibility. We investigated how titanium coated with pectins, adaptable bioactive plant polysaccharides with anti-inflammatory effects, supports osteoblast differentiation. MC3T3-E1 cells, primary murine osteoblasts, and human mesenchymal cells (hMC) were cultured on titanium coated with rhamnogalacturonan-rich modified hairy regions (MHR-A and MHR-B) of apple pectin. Alkaline phosphatase (ALP) expression and activity, calcium deposition, and cell spreading were investigated. MHR-B, but not MHR-A, supports osteoblast differentiation. The MHR-A surface was not mineralized, but on MHR-B, the average mineralized area was 14.0% with MC3T3-E1 cells and 26.6% with primary osteoblasts. The ALP activity of hMCs on MHR-A was 58.3% at day 7 and 9.3% from that of MHR-B at day 10. These data indicate that modified pectin nanocoatings may enhance the biocompatibility of bone and dental implants.     

The use of Teflon in orbital floor reconstruction following blunt facial trauma: a 20-year experience

A myriad of materials have been used for reestablishing continuity of the orbital floor following blunt facial trauma. Traditionally, autogenous grafts have been the material of choice for orbital floor reconstruction; however, alloplastic materials have gained popularity because of their availability and ease of use. A large clinical experience with long-term treatment results has never been reported for any substance used in orbital floor reconstruction. The purpose of this study was to review our long-term treatment results using Teflon for orbital floor reconstruction following blunt trauma, with emphasis on the incidence of infection, extrusion, and implant displacement. This report presents a 20-year review of 230 Teflon implants for reconstruction of traumatic orbital floor defects. With a mean follow-up period of 30 months, there was only one implant infection and no complications of extrusion or implant displacement. These findings support the use of Teflon as a safe and effective material for the reconstruction of orbital floor defects following blunt facial trauma.     

Experimental hydroxyapatite cement cranioplasty.

Hydroxyapatite cement is a calcium phosphate-based material that when mixed with water forms a dense paste that sets within 15 minutes and isothermically converts in vivo to a microporous hydroxyapatite implant. This cement was used to reconstruct bilateral 2.5-cm-diameter full-thickness critical-sized parietal skull defects in six cats. One side was reconstructed with 100 percent hydroxyapatite cement, and the other with a mixture of 50 percent hydroxyapatite cement and 50 percent ground autogenous bone by weight. These animals were sacrificed at 6 and 12 months after implantation. Positive and negative controls also were prepared. The anatomic contour of the soft tissue overlying all hydroxyapatite cement implants was well maintained, there were no wound infections or structural failures, and the implants were well tolerated histologically. None of the negative (unreconstructed) control defects was completely filled with repair bone, and all positive (methyl methacrylate) controls demonstrated foreign-body giant-cell formation and fibrous encapsulation of the implants. Examination of decalcified and undecalcified sections revealed progressive but variable replacement of the cement by new bone and soft tissue without a change in the shape or volume of the hydroxyapatite cement-reconstructed areas. New bone comprised 77.3 and 64.7 percent of the tissue replacing the hydroxyapatite cement and hydroxyapatite cement-bone implants, respectively. Replacement of the hydroxyapatite cement implants by new bone is postulated to occur by a combination of osteoconduction and implant resorption. These results indicate that further experimental research leading to the possible application of hydroxyapatite cement for full-thickness calvarial defect reconstruction in humans is warranted.     

Heat and radiofrequency plasma glow discharge pretreatment of a titanium alloy: Eveidence for enhanced osteoinductive properties

It is believed that orthopedic and implant longevity can be improved by optimizing fixation, or direct bone‐implant contact, through the stimulation of new bone formation around the implant. The purpose of this study was to determine whether heat (600°C) or radiofrequency plasma glow discharge (RFGD) pretreatment of Ti6Al4V stimulated calcium‐phosphate mineral formation in cultures of attached MC3T3 osteoprogenitor cells with or without a fibronectin coating. Calcium‐phosphate mineral was analyzed by flame atomic absorption spectrophotometry, scanning electron microscopy (SEM)/electron dispersive X‐ray microanalysis (EDAX) and Fourier transformed infrared spectroscopy (FTIR). RFGD and heat pretreatments produced a general pattern of increased total soluble calcium levels, although the effect of heat pretreatment was greater than that of RFGD. SEM/EDAX showed the presence of calcium‐and phosphorus‐containing particles on untreated and treated disks that were more numerous on fibronectin‐coated disks. These particles were observed earliest (1 week) on RFGD‐pretreated surfaces. FTIR analyses showed that the heat pretreatment produced a general pattern of increased levels of apatite mineral at 2–4 weeks; a greater effect was observed for fibronectin‐coated disks compared to uncoated disks. The observed findings suggest that heat pretreatment of Ti6Al4V increased the total mass of the mineral formed in MC3T3 osteoprogenitor cell cultures more than RFGD while the latter pretreatment hastened the early deposition of mineral. These findings help to support the hypothesis that the pretreatments enhance the osteoinductive properties of the alloy. J. Cell. Biochem. 114: 1917–1927, 2013. © 2013 Wiley Periodicals, Inc.     

Comparative Characteristics of Porous Bioceramics for an Osteogenic Response In Vitro and In Vivo

Porous calcium phosphate ceramics are used in orthopedic and craniofacial applications to treat bone loss, or in dental applications to replace missing teeth. The implantation of these materials, however, does not induce stem cell differentiation, so suitable additional materials such as porous calcium phosphate discs are needed to influence physicochemical responses or structural changes. Rabbit adipose-derived stem cells (ADSC) and mouse osteoblastic cells (MC3T3-E1) were evaluated in vitro by the MTT assay, semi-quantitative RT-PCR, and immunoblotting using cells cultured in medium supplemented with extracts from bioceramics, including calcium metaphosphate (CMP), hydroxyapatite (HA) and collagen-grafted HA (HA-col). In vivo evaluation of the bone forming capacity of these bioceramics in rat models using femur defects and intramuscular implants for 12 weeks was performed. Histological analysis showed that newly formed stromal-rich tissues were observed in all the implanted regions and that the implants showed positive immunoreaction against type I collagen and alkaline phosphatase (ALP). The intramuscular implant region, in particular, showed strong positive immunoreactivity for both type I collagen and ALP, which was further confirmed by mRNA expression and immunoblotting results, indicating that each bioceramic material enhanced osteogenesis stimulation. These results support our hypothesis that smart bioceramics can induce osteoconduction and osteoinduction in vivo, although mature bone formation, including lacunae, osteocytes, and mineralization, was not prominent until 12 weeks after implantation.     

骨诱导无机材料BAM 修复牙种植体周围骨缺损的实验研究

目的:评价骨诱导磷酸钙生物陶瓷(BAMOICPC)与可吸收胶原膜(BME-10X医用胶原膜)在牙种植体周围骨缺损中的修复能力。方法:在兔股骨上植入羟基磷灰石涂层BLB种植体,然后在其侧壁制造高4 mm、宽3 mm、深2 mm的骨缺损。对照组为单纯侧壁骨缺损,实验A组骨缺损区仅覆盖BME-10X膜,B组骨缺损区植入BAMOICPC,C组骨缺损区植入BAMOICPC并加盖BME-10X膜。于术后6个月取带种植体的骨段,通过HE染色和扫描电镜(SEM)分析。结果:对照组骨缺损区种植体表面见纤维包裹,实验A组骨缺损边界区少许骨质移行覆盖,实验B组下半部分缺损区新生骨覆盖。C组新生骨完全覆盖骨缺损区,且较B组硬度高,扫描电镜见与种植体结合更紧密。组织学观察B、C两实验组新生骨均可见比较成熟的哈弗氏管系统。结论:骨诱导磷酸钙生物陶瓷BAMOICPC是一种较理想的骨替代材料,联合运用胶原膜修复种植体周骨缺损效果佳。     

The biomaterial influences the ossification after sinus floor elevation using tissue-engineered bone grafts

Sinus floor elevation is the standard procedure that allows dental implant insertion in the atrophic posterior maxilla. Instead of autogenous bone, tissue-engineered bone grafts can be used, but clear comparative clinical studies also assessing the influence of the biomaterial are missing. In six patients, tissue-engineered bone grafts were used in eight sinus floor elevations. After culturing osteoblast-like cells from biopsies of the maxilla, they were seeded on scaffolds made either from demineralised bovine bone matrix (DBBM) or from solvent-dehydrated mineralised bone (SDBB), and grafted. In all patients primary wound healing was without complications, except for one patient in the SDBB group. After 12 months, implant insertion was possible only in the SDBB group; in the DBBM group, fibrous connective tissue was found in an attempt of implant insertion. After 5 months, implant placement was performed in one patient of each group. However, the two implants inserted in the DBBM group were lost after 6 weeks. Histology of the bone cores in the DBBM group at 5 months showed lamellar bone and osteoid, and at 12 months showed fibrous connective tissue. Inflammation and some resorption of the scaffold was found 5 months after SDBB grafting, and after 12 months cancellous bone formation encapsulating SDBB remnants were observed. These preliminary data suggest that the preparation method of the bovine bone matrix, in particular the mineral content, and therefore the mechanical stability may have some influence on the generation of new bone.     

Aesthetic and restorative midface lifting with hand-carved,expanded polytetrafluoroethylene orbital rim implants

The midface lift represents an important advance in aesthetic and reconstructive surgery. However, the need for reliable fixation along the orbital rim has been a significant challenge. Furthermore, volume is needed at the orbital rim, to compensate for long-term remodeling of the bone of the orbital rim and malar face. A technique using a hand-carved, expanded polytetrafluoroethylene implant that is permanently anchored to the orbital rim with titanium microscrews, creating a site for fixation of the advanced midface soft tissues, was developed. This report presents a retrospective, uncontrolled, case series of 41 consecutive patients who underwent transconjunctival midface operations with these implants, and it addresses a variety of midface aesthetic and reconstructive deficits. Only patients with at least 6 months of follow-up data were included in the study. To date, significant complications have been limited. The complications included two cases of implant palpability, with only one requiring surgical modification. One patient underwent implant removal because of skin breakdown and infection related to recurrent squamous cell carcinoma. One patient required revisional lateral canthoplasty for reasons of symmetry. On the basis of this series, hand-carved, expanded polytetrafluoroethylene implants seem to have significant advantages, compared with previously available orbital rim implants. These advantages include the ability to easily modify the implant for the individual anatomical needs, the creation of a secure anchor for fixation of advanced midface soft tissues, excellent tolerance of the implant material, and the ability to place the implant with limited exposure. The greatest disadvantage is the need for the surgeon to carve the implant, which requires time and carving skill. Despite this limitation, the technique is promising.     

Mechanical behavior of a new biphasic calcium phosphate bone graft

The aim of this study was to create a new porous calcium phosphate implant for use as a synthetic bone graft substitute. Porous bioceramic was fabricated using a foam-casting method. By using polyurethane foam and a slurry containing hydroxyapatite-dicalcium phosphate powder, water, and additives, a highly porous structure (66 ± 5%) was created. The porous specimens possess an elastic modulus of 330 ± 32 MPa and a compressive strength of 10.3 ± 1.7 MPa. The X-ray diffraction patterns show hydroxyapatite and beta-pyrophosphate phases after sintering. A rabbit model was developed to evaluate the compressive strength and elastic modulus of cancellous bone defects treated with these porous synthetic implants. The compressive mechanical properties became weaker until the second month post implantation. After the second month, these properties increased slightly and remained higher than control values. New bone formed on the outside surface and on the macropore walls of the specimens, as osteoids and osteoclasts were evident two months postoperatively. Considering these properties, these synthetic porous calcium phosphate implants could be applicable as cancellous bone substitutes.     

Orbital floor and infraorbital rim reconstruction after total maxillectomy using a vascularized calvarial bone flap.

A number of techniques have been introduced to support the orbital floor after maxillectomy without orbital exenteration. These methods include skin graft or muscular sling, but they have resulted in severe complications, such as enophthalmos, global ptosis, diplopia, and facial deformity. Currently, advanced microvascular reconstruction using bone and soft tissue is performed by many surgeons. This usually results in the filling of the postmaxillectomy defect, but the lack of support for the orbital rim and floor by the bone flap may still cause the complications mentioned above. Vascularized calvarial bone flap was chosen in this study for reconstruction of the orbital floor and infraorbital rim to function as a buttress, to reconstruct recipient sites of poor vascular bed after radiation therapy, and to withstand further postoperative radiation. By providing a solid floor and rim, these complications can be prevented with satisfactory function and aesthetically acceptable results. From September of 1995 to July of 1998, we performed vascularized bone flap for the reconstruction of the orbital floor and infraorbital rim in four cases after total maxillectomy involving the orbital floor. With a follow-up period from 19 to 35 months (mean, 27 months), we obtained significant improvement of functional and aesthetically acceptable results without global ptosis, enophthalmos, diplopia, or severe facial contour deformity.     

The Biocompatibility of Porous vs Non-Porous Bone Cements: A New Methodological Approach

Composite cements have been shown to be biocompatible, bioactive, with good mechanical properties and capability to bind to the bone. Despite these interesting characteristic, in vivo studies on animal models are still incomplete and ultrastructural data are lacking. The acquisition of new ultrastructural data is hampered by uncertainties in the methods of preparation of histological samples due to the use of resins that melt methacrylate present in bone cement composition. A new porous acrylic cement composed of polymethyl-metacrylate (PMMA) and β-tricalcium-phosphate (p-TCP) was developed and tested on an animal model. The cement was implanted in femurs of 8 New Zealand White rabbits, which were observed for 8 weeks before their sacrifice. Histological samples were prepared with an infiltration process of LR white resin and then the specimens were studied by X-rays, histology and scanning electron microscopy (SEM). As a control, an acrylic standard cement, commonly used in clinical procedures, was chosen. Radiographic ultrastructural and histological exams have allowed finding an excellent biocompatibility of the new porous cement. The high degree of osteointegration was demonstrated by growth of neo-created bone tissue inside the cement sample. Local or systemic toxicity signs were not detected. The present work shows that the proposed procedure for the evaluation of biocompatibility, based on the use of LR white resin allows to make a thorough and objective assessment of the biocompatibility of porous and non-porous bone cements.Key words: calcium phosphate cement, osteointegration, biocompatibility, osteoconduction, porosity     

具有中空贯通管结构的磷酸钙骨水泥的制备研究

目前,磷酸钙骨水泥因其具有优良的生物性能已被广泛用于骨组织工程,但它自固化后只是形成具有微孔和封闭气孔的致密块体,其孔径尺寸和连通性仍远达不到骨组织工程的最佳要求.本研究采用α-TCP为原料,以过氧化氢作为发泡剂,使用模具插针法制得一种具有大孔径和中空管的多孔磷酸钙骨水泥材料.孔径达到900μm,孔隙率为50.67%,抗折强度达到5.84MPa.通过扫描电镜照片观察和分析微观结构.结果表明,通过这种方法可以制得具有理想孔径尺寸和连通性的多孔磷酸钙骨水泥,可以说,这为制备用于骨组织工程的多孔磷酸钙骨水泥创造了一种新的方法.     

The effect of autologous bone marrow stromal cells differentiated on scaffolds for canine tibial bone reconstruction

Bone marrow contains mesenchymal stem cells that form many tissues. Various scaffolds are available for bone reconstruction by tissue engineering. Osteoblastic differentiated bone marrow stromal cells (BMSC) promote osteogenesis on scaffolds and stimulate bone regeneration. We investigated the use of cultured autologous BMSC on different scaffolds for healing defects in tibias of adult male canines. BMSC were isolated from canine humerus bone marrow, differentiated into osteoblasts in culture and loaded onto porous ceramic scaffolds including hydroxyapatite 1, hydroxyapatite gel and calcium phosphate. Osteoblast differentiation was verified by osteonectine and osteocalcine immunocytochemistry. The scaffolds with stromal cells were implanted in the tibial defect. Scaffolds without stromal cells were used as controls. Sections from the defects were processed for histological, ultrastructural, immunohistochemical and histomorphometric analyses to analyze the healing of the defects. BMSC were spread, allowed to proliferate and differentiate to osteoblasts as shown by alizarin red histochemistry, and osteocalcine and osteonectine immunostaining. Scanning electron microscopy showed that BMSC on the scaffolds were more active and adhesive to the calcium phosphate scaffold compared to the others. Macroscopic bone formation was observed in all groups, but scaffolds with stromal cells produced significantly better results. Bone healing occurred earlier and faster with stromal cells on the calcium phosphate scaffold and produced more callus compared to other scaffolds. Tissue healing and osteoblastic marker expression also were better with stromal cells on the scaffolds. Increased trabecula formation, cell density and decreased fibrosis were observed in the calcium phosphate scaffold with stromal cells. Autologous cultured stromal cells on the scaffolds were useful for healing of canine tibial bone defects. The calcium phosphate scaffold was the best for both cell differentiation in vitro and bone regeneration in vivo. It may be possible to improve healing of bone defects in humans using stem cells from bone marrow.     

高密度聚乙烯多孔材料在创伤性眶底缺损整复的临床观察

目的：观察高密度聚乙烯多孔材料Medpor在眶底缺损修复中的临床应用效果,分析相关并发症的术后改善情况。方法：2001年1月起选取20例创伤性眶底缺损患者采用高密度聚乙烯多孔材料作为眶底填充材料实施眼眶重建术,同期选取16例常规钛金属修复作为对照。术后6m嘱患者进行复查评价两者的治疗效果;评价内容包括息者外貌、眼球功能和创伤性眶底缺损常见并发症的改善情况等;术前履术后6m头颅三维螺旋CT检查观察眶底缺损修复后眼眶结构的连续性。结果：36例患者术后面中部对称性都逐渐恢复,眼球的运动功能明显好转。创伤性眶底缺损常见并发症如眼球内陷、复视及眶下神经感觉迟钝术后明显改善,采用Medpor材料修复和常规钛金属修复的患者无明显差异。同期螺旋三维CT显示与钛金属修复相比,采用生物材料保持了眶结构的连续性,维持了正常眶容积。有利于缺损修复,骨缺损面积明显缩小。结论：研究表明高密度聚乙烯多孔材料操作容易,可塑性高,材料在体内可促进自体骨组织长入,具有较好的修复效果,时临床眼眶修复重建的手术治疗具有一定的指导意义。     

Biomimetic calcium phosphate mineralization with multifunctional elastin-like recombinamers

Biomimetic hybrid materials based on a polymeric and an inorganic component such as calcium phosphate are potentially useful for bone repair. The current study reports on a new approach toward biomimetic hybrid materials using a set of recombinamers (recombinant protein materials obtained from a synthetic gene) as crystallization additive for calcium phosphate. The recombinamers contain elements from elastin, an elastic structural protein, and statherin, a salivary protein. Via genetic engineering, the basic elastin sequence was modified with the SN(A)15 domain of statherin, whose interaction with calcium phosphate is well-established. These new materials retain the biocompatibility, "smart" nature, and desired mechanical behavior of the elastin-like recombinamer (ELR) family. Mineralization in simulated body fluid (SBF) in the presence of these recombinamers reveals surprising differences. Two of the polymers inhibit calcium phosphate deposition (although they contain the statherin segment). In contrast, the third polymer, which has a triblock structure, efficiently controls the calcium phosphate formation, yielding spherical hydroxyapatite (HAP) nanoparticles with diameters from 1 to 3 nm after 1 week in SBF at 37 °C. However, at lower temperatures, no precipitation is observed with any of the polymers. The data thus suggest that the molecular design of ELRs containing statherin segments and the selection of an appropriate polymer structure are key parameters to obtain functional materials for the development of intelligent systems for hard tissue engineering and subsequent in vivo applications.     

Tissue sources of bone marrow colony stimulating factor

Possible tissue sources in C57BL mice of the serum factor stimulating colony formation in vitro by mouse bone marrow cells have been investigated. A reproducible technique employing batch chromatography on calcium phosphate gel was developed for the extraction and assay of material with colony stimulating activity from mouse tissues. Sixteen hematopoietic and non-hematopoietic tissues from C57BL mice were found to vary widely in their content of extractable activity. Characterisation of the colony stimulating factors (CSF's) from these tissues by assay of stepped concentrations of eluate showed that CSF's from most tissues were similar in chromatographic behavior, but all differed significantly from those of serum in being both more disperse and more firmly bound to calcium phosphate gel. Male submaxillary salivary gland gave the richest yield of CSF. CSF from this source displayed a greater dispersity on and affinity to calcium phosphate, a lower electrophoretic mobility and a smaller average sedimentation coefficient than that from any other source investigated. Colony morphology appeared to be identical for all tissue sources investigated.     

Direct local approach through a W-shaped incision in moderate or severe blowout fractures of the medial orbital wall

For moderate or severe blowout fractures of the medial orbital wall, the goals of treatment are complete reduction of the herniated soft tissue and anatomic reconstruction of the wall without surgical complications. Various surgical approaches have been used, depending on the anatomic location and the extent of medial wall fracture. However, there is no consistent method to achieve the treatment goals with minimal morbidity because of one or more problems of limitation of entire medial wall exposure, limitation of large implant or bone graft insertion, surgical damage of important periorbital or intraorbital structures, or postoperative scar deformities. In this study, a direct local approach through a 3-cm, W-shaped incision on the superior medial orbital area was used as a consistent method to reconstruct medial orbital blowout fractures. The angle of the W-limbs is 110 to 120 degrees. Four limbs of the W were placed parallel or oblique to the relaxed skin tension lines. This technique was applied to 39 orbits of 37 patients with moderate or severe blowout fractures of the medial orbital wall. This approach provided exposure of the entire medial orbital wall, adequate placement of a large implant, short operation time within 2 hours, and no damage of important internal structures. Postoperative computed tomographic scans showed complete reduction of the herniated orbital tissues and anatomic reconstruction of the medial orbital wall without complication related to the surgical approach in all cases. During the follow-up period of 6 to 14 months, excellent functional and cosmetic results were observed with an inconspicuous scar without secondary scar deformities. Therefore, a direct local approach through a W-shaped incision on the superior medial orbit may be a consistent method to gain the surgical goal in treatment of moderate or severe blowout fractures of the medial orbital wall.     

Effect of heparin and alendronate coating on titanium surfaces on inhibition of osteoclast and enhancement of osteoblast function

The failure of orthopedic and dental implants has been attributed mainly to loosening of the implant from host bone, which may be due to weak bonding of the implant material to bone tissue. Titanium (Ti) is used in the field of orthopedic and dental implants because of its excellent biocompatibility and outstanding mechanical properties. Therefore, in the field of materials science and tissue engineering, there has been extensive research to immobilize bioactive molecules on the surface of implant materials in order to provide the implants with improved adhesion to the host bone tissue.In this study, chemically active functional groups were introduced on the surface of Ti by a grafting reaction with heparin and then the Ti was functionalized by immobilizing alendronate onto the heparin-grafted surface. In the MC3T3-E1 cell osteogenic differentiation study, the alendronate-immobilized Ti substrates significantly enhanced alkaline phosphatase activity (ALP) and calcium content. Additionally, nuclear factor kappa B ligand (RANKL)-induced osteoclast differentiation of RAW264.7 cells was inhibited with the alendronate-immobilized Ti as confirmed by TRAP analysis. Real time PCR analysis showed that mRNA expressions of osteocalcin and osteopontin, which are markers for osteogenesis, were upregulated in MC3T3-E1 cells cultured on alendronate-immobilized Ti. The mRNA expressions of TRAP and Cathepsin K, markers for osteoclastogenesis, in RAW264.7 cells cultured on alendronate-immobilized Ti were down-regulated. Our study suggests that alendronate-immobilized Ti may be a bioactive implant with dual functions to enhance osteoblast differentiation and to inhibit osteoclast differentiation simultaneously.