Design,fabrication,and structural safety validation of 3D-printable biporous bone augments

The use of commercial products such as a cup and liner for total hip arthroplasty for patients with severe bone defects has a high probability of failure.In these patients the cup alone cannot cover the bone defect,and thus,an additional augment or cage is required.In this study,we designed three-dimensional(3D)printable bone augments as an alternative to surgeries using reinforcement cages.Thirty-five sharp-edged bone augments of various sizes were 3D printed.A biporous structure was designed to reduce the weight of the augment and to facilitate bone ingrowth.Two types of frames were used to prevent damage to the augment’s porous structure and maintain its stability during printing.Furthermore,two types of holes were provided for easy augment fixation at various angles.Fatigue tests were performed on a combination of worst-case sizes derived using finite element analysis.The test results confirmed the structural stability of the specimens at a load of 5340 N.Although the porosity of the specimens was measured to be 63.70%,it cannot be said that the porous nature was uniformly distributed because porosity tests were performed locally and randomly.In summary,3D-printable biporous bone augments capable of bonding from various angles and bidirectionally through angulation and bottom-plane screw holes are proposed.The mechanical results with bone augments indicate good structural safety in patients.However,further research is necessary to study the clinical applications of the proposed bone augment.

The Use of Cortical Bone Wedges from the Mandibular Ramus “Wedge Technique”: For 3-Dimensional Bone Augmentation of the Atrophic Ridges. Technique Presentation and Report of Case Series

Purpose: Autogenous bone was still considered as the gold standard in bone augmentations prior to implants insertion at the atrophic ridges. However if large bone grafts are needed to augment multiple edentulous atrophic segments, extraoral donor sites may be mandatory. The aim of this report is to introduce the Fares Wedge Technique, as a new bone augmentation method that can augment multiple edentulous ridges with intraoral cortical bone grafts. Methods: This report includes patients with moderate to severe ridge atrophy in different regions of the both jaws who were treated over 6-years period (2009-215) with wedge Technique (WT). Patients received panorex immediately after the surgery, and they were examined clinically and radiographically (periapical) every 2 weeks. At 4 months, computed tomography was performed to evaluate the bone gain. Reentry was performed after 4 to 5 months to evaluate the new bone volume and quality and to insert implants. At this stage specimens for histologic examination were also obtained. Results: 39 augmentation sites in 22 patients (15 women, 7 men: mean age 47 years) were followed 12 to 52 months. The healing process was uneventful, with minimal morbidity. The success rate was 95%, and the bone gain average was 3 - 6 mm vertically and 3 - 9 mm horizontally. In two patients the graft was partially exposed and treated with shaving and rounding the exposed wedges, but the augmentations were saved. In one case the majority of the bone graft was lost. At 38 sites the patients had successfully received 114 implants. Conclusions: wedge technique can augment multiple segments of atrophic ridges with small amount of autogenic graft. The bone volume that achieved was satisfying, especially that the majority of the augmented areas were at posterior mandibular defects.

3D-printed bioactive ceramic scaffolds with biomimetic micro/nano-HAp surfaces mediated cell fate and promoted bone augmentation of the bone-implant interface in vivo

Calcium phosphate bio-ceramics are osteo-conductive,but it remains a challenge to promote the induction of bone augmentation and capillary formation.The surface micro/nano-topography of materials can be recognized by cells and then the cell fate are mediated.Traditional regulation methods of carving surface structures on bio-ceramics employ mineral reagents and organic additives,which might introduce impurity phases and affect the biological results.In a previous study,a facile and novel method was utilized with ultrapure water as the unique reagent for hydrothermal treatment,and a uniform hydroxyapatite(HAp)surface layer was constructed on composite ceramics(β-TCP/CaSiO_(3))in situ.Further combined with 3D printing technology,biomimetic hierarchical structure scaffolds were fabricated with interconnected porous composite ceramic scaffolds as the architecture and micro/nano-rod hybrid HAp as the surface layer.The obtained HAp surface layer favoured cell adhesion,alleviated the cytotoxicity of precursor scaffolds,and upregulated the cellular differentiation of mBMSCs and gene expression of HUVECs in vitro.In vivo studies showed that capillary formation,bone augmentation and new bone matrix formation were upregulated after the HAp surface layer was obtained,and the results confirmed that the fabricated biomimetic hierarchical structure scaffold could be an effective candidate for bone regeneration.

Gene-activated matrix harboring a miR20a-expressing plasmid promotes rat cranial bone augmentation

Gene-activated matrix(GAM)has a potential usefulness in bone engineering as an alternate strategy for the lasting release of osteogenic proteins but efficient methods to generate non-viral GAM remain to be established.In this study,we investigated whether an atelocollagen-based GAM containing naked-plasmid(p)DNAs encoding microRNA(miR)20a,which may promote osteogenesis in vivo via multiple pathways associated with the osteogenic differentiation of mesenchymal stem/progenitor cells(MSCs),facilitates rat cranial bone augmentation.First,we confirmed the osteoblastic differentiation functions of generated pDNA encoding miR20a(pmiR20a)in vitro,and its transfection regulated the expression of several of target genes,such as Bambi1 and PPARc,in rat bone marrow MSCs and induced the increased expression of BMP4.Then,when GAMs fabricated by mixing 100 ll of 2%bovine atelocollagen,20mg b-TCP granules and 0.5mg(3.3 lg/ll)AcGFP plasmid-vectors encoding miR20a were transplanted to rat cranial bone surface,the promoted vertical bone augmentation was clearly recognized up to 8 weeks after transplantation,as were upregulation of VEGFs and BMP4 expressions at the early stages of transplantation.Thus,GAM-based miR delivery may provide an alternative non-viral approach by improving transgene efficacy via a small sequence that can regulate the multiple pathways.

Bone block from lateral window-correcting vertical and horizontal bone deficiency in maxilla posterior site:A case report

BACKGROUND Lateral window approach for sinus floor lift is commonly used for vertical bone augmentation in cases when the residual bone height is less than 5 mm.However,managing cases becomes more challenging when a maxillary sinus pseudocyst is present or when there is insufficient bone width.In this case,we utilized the bone window prepared during the lateral window sinus lift as a shell for horizontal bone augmentation.This allowed for simultaneous horizontal and vertical bone augmentation immediately after the removal of the maxillary sinus pseudocyst.CASE SUMMARY A 28-year-old female presented to our clinic with the chief complaint of missing upper left posterior teeth.Intraoral examination showed a horizontal deficiency of the alveolar ridge contour.The height of the alveolar bone was approximately 3.6 mm on cone beam computed tomography(CBCT).And a typical well-defined'dome-shaped'lesion in maxillary sinus was observed on CBCT imaging.The lateral bony window was prepared using a piezo-ultrasonic device,then the bony window was fixed to the buccal side of the 26 alveolar ridge using a titanium screw with a length of 10 mm and a diameter of 1.5 mm.The space between the bony window and the alveolar ridge was filled with Bio-Oss,covered with a Bio-Gide collagen membrane,and subsequently sutured.Nine months later,the patient’s bone width increased from 4.8 to 10.5 mm,and the bone height increased from 3.6 to 15.6 mm.Subsequently,a Straumann^(■)4.1 mm×10 mm implant was placed.The final all-ceramic crown restoration was completed four months later,and both clinical and radiographic examinations showed that the implant was successful,and the patient was satisfied with the results.CONCLUSION The bone block harvested from the lateral window sinus lift can be used for simultaneous horizontal bone augmentation acting as a shell for good two-dimensional bone augmentation.

Treatment of Bone Defect with Modular Metal Augmentation Using a Downsized Block in Total Knee Arthroplasty: Technical Note and Report of 17 Cases

In total knee arthroplasty (TKA), a treatment of bone defect varies depending on the location and extent of defect and requires proper surgical procedure. Metal augmentation is readily available for both femoral and tibial bone defects. We report the operative technique of modular metal augmentation using a downsized block for ambiguous proximal tibial and distal femoral bone defects in primary and revision TKA. Regarding bone defects, bone loss can be minimized by using a different size of metal augmentation, and suitable reinforcement for bone defects can be achieved. Once our technique is properly used, it will be very helpful in treating bone defects.

双侧经皮椎体强化术中不同骨水泥填充量及分布形态的有限元分析

背景:采用双侧经皮椎体强化治疗骨质疏松性椎体压缩骨折中,作者发现当骨水泥注射总量达4 mL及以上时会在X射线片上呈现不同的分布形态,然而关于骨水泥分布形态对骨折椎体生物力学特性的影响鲜有报道。目的:利用有限元法进一步探讨骨水泥填充量及分布形态对骨折椎体生物力学的影响。方法:建立L_1-L_3骨质疏松有限元模型,在L_2节段模拟椎体压缩骨折,在骨质疏松性椎体压缩骨折模型上分别模拟4 mL及6 mL骨水泥注入量及双侧部分融合(FH型)、完全融合(FO型)、对称分离(SA型)、非对称分离(SN型)4种骨水泥分布形态,共获得9组模型。在相同边界条件下进行三维有限元求解,比较L_2骨折椎体的应力及位移。结果与结论:(1)9组模型的最大应力均集中于L_2骨折区域,各骨水泥填充骨折模型的L_2最大应力和最大位移均小于无骨水泥填充骨折模型,说明骨水泥填充治疗骨质疏松性椎体压缩骨折有效;(2)与4 mL骨水泥填充相比,6 mL骨水泥填充在提高骨折椎体稳定性的同时可显著降低骨折椎体应力,增强椎体强度;(3)在相同运动状态下,FH型组骨折椎体应力均为最小,其次为SA型组,该两组接近,FO型组骨折椎体应力最大,在侧弯动作中尤为明显,可能与骨水泥团块形状导致侧方应力集中有关;FH型组骨折椎体位移最小,FO型组骨折椎体位移最大;(4)结果显示,增加骨水泥注入剂量可以降低骨折椎体应力,提高稳定性,但会增加渗漏风险;双侧对称弥散分布骨水泥(FH型、SA型)在恢复椎体强度及稳定性上均优于完全融合、非对称分离骨水泥,因此,临床上行双侧经皮椎体强化治疗骨质疏松性椎体压缩骨折时,首先保证双侧对称弥散分布,优先推荐双侧部分融合型分布,可获得合适的应力刺激及较好的稳定性。

经皮椎体成形联合椎弓根强化治疗重度骨质疏松性椎体骨折的有限元分析

背景:椎弓根内骨水泥灌注联合椎体成形已被用于治疗Kummell病和椎弓根溶骨性转移瘤等疾病,但该手术方式对相邻椎体及椎间盘的影响尚不明确。目的:应用三维有限元模型探讨经皮椎体成形联合椎弓根强化术治疗重度骨质疏松性椎体骨折对邻近节段椎体以及椎间盘相关生物力学的影响。方法:选择1位已完成经皮椎体成形联合椎弓根强化术的重度骨质疏松性椎体骨折(L1)女性患者,并提取其术前及术后的CT文件,研究范围为T_(12)-L_(2)(包括伤椎、邻近椎体和椎间盘)。通过Mimics、SolidWorks和Geomagic等软件分别建立了术前、术后三维脊柱功能单元的有限元模型。在T_(12)上终板垂直方向加载500 N力矩和10 N·m旋转力矩,模拟前屈、后伸、侧屈和旋转等运动方位,分析手术前后相邻节段椎体终板和椎间盘的应力变化情况。结果与结论:①成功建立了术前和术后脊柱功能单元的三维有限元模型;②通过计算得出,在模拟载荷下,术后T_(12)下终板应力分布更均匀且最大应力值减小,与术前相比无显著差异(P>0.05);术后L_(2)上终板应力分布更均匀且最大应力与术前无显著差异(P>0.05);同样,术后T_(12)/L_(1)、L_(1)/L_(2)椎间盘应力分布也更均匀且最大应力值均显著减小(P<0.05);③因此,经皮椎体成形联合椎弓根强化能够有效改善术后相邻椎体终板和椎间盘的应力分布,并能够减小应力,最终降低术后再骨折风险以及显著延缓椎间盘退变。

Minimally Invasive Subpericranial Model: Can It Be Used to Study Bone Substitutes?

Objective: To evaluate the feasibility and effectiveness of a new approach for craniofacial augmentation by a minimally-invasive subpericranial injection. Three commercially available semi-liquid bioceramic bone-grafting materials were examined for this application in a rat model. Material and Methods: Twenty-four adult male rats were randomly assigned to undergo onlay calvarial grafting by subpericranial injection of three semi-liquid bone void fillers: Norian SRS(calcium phosphate), ChronOs InjectTM (porous beta-tricalcium phosphate), or BonePlastharvested after 24 hours to serve as controls. The rest were studied after 16 weeks. The volume fraction of the following parameters was morphometrically measured: new bone, blood vessels, residual bone filler and inflammation. Results: In all study groups (including controls), histological examination demonstrated that bone fillers were successfully delivered to the desired subpericranial space by the percutaneous injection method. New bone formation was evidenced adjacent to the cranial bone in all the study groups. The Norian filler material survived in a significantly higher volume fraction (38.4% ± 6.5%) than the ChronOs filler (18.8% ± 1.6%;P 0.0001) and the BonePlast filler (17.8% ± 1.5%;P 0.0001). New bone was formed in all groups, particularly adjacent to the interface of graft material with native bone but only to minimal extent. Conclusion: This new approach for craniomaxillofacial augmentation was successfully demonstrated in a rat model. The Norian filler (calcium phosphate) demonstrated superior space preservation abilities. This model may be further applied to test new injectable bone substitutes in the craniomaxillofacial area.

Mesenchymal stem cells in maxillary sinus augmentation: A systematic review with meta-analysis

AIM: To investigate the effectiveness of mesenchymal stem cells(MSCs) in maxillary sinus augmentation(MSA), with various scaffold materials.METHODS: MEDLINE, EMBASE and SCOPUS were searched using keywords such as sinus graft, MSA, maxillary sinus lift, sinus floor elevation, MSC and cellbased, in different combinations. The searches included full text articles written in English, published over a 10-year period(2004-2014). Inclusion criteria were clinical/radiographic and histologic/ histomorphometric studies in humans and animals, on the use of MSCs in MSA. Meta-analysis was performed only for experimental studies(randomized controlled trials and controlled trials) involving MSA, with an outcome measurement of histologic evaluation with histomorphometric analysis reported. Mean and standard deviation values of newly formed bone from each study were used, and weighted mean values were assessed to account for the difference in the number of subjects among the different studies. To compare the results between the test and the control groups, the differences of regenerated bone in mean and 95% confidence intervals were calculated.RESULTS: Thirty-nine studies(18 animal studies and 21 human studies) published over a 10-year period(between 2004 and 2014) were considered to be eligible for inclusion in the present literature review. These studies demonstrated considerable variation with respect to study type, study design, follow-up, and results. Metaanalysis was performed on 9 studies(7 animal studies and 2 human studies). The weighted mean difference estimate from a random-effect model was 9.5%(95%CI: 3.6%-15.4%), suggesting a positive effect of stem cells on bone regeneration. Heterogeneity was measured by the I2 index. The formal test confirmed the presence of substantial heterogeneity(I2 = 83%, P < 0.0001). In attempt to explain the substantial heterogeneity observed, we considered a meta-regression model with publication year, support type(animal vs humans) andfollow-up length(8 or 12 wk) as covariates. After adding publication year, support type and follow-up length to the meta-regression model, heterogeneity was no longer significant(I2 = 33%, P = 0.25).CONCLUSION: Several studies have demonstrated the potential for cell-based approaches in MSA; further clinical trials are needed to confirm these results.

骨增量材料中血管新生性能的作用及认识

骨增量是种植治疗中解决骨量不足状况的必要手段,骨增量成功的关键之一是植入的骨增量材料应能发生血管新生,形成与宿主组织有效血氧交换的网络。本文就骨增量材料的血管新生作用研究进展进行阐述,为促进骨增量材料的研发及其临床转化提供建议和参考。

口腔种植骨增量中的减张技术

临床上,种植位点骨量不足是种植治疗中常遇到的难题。为确保种植区符合种植条件,骨增量手术尤为重要。而骨增量手术成功的关键要素之一是创口无张力的一期愈合。减张技术是获得创口无张力愈合的关键。本文将从减张切口、减张瓣及减张缝合3个方面介绍口腔种植骨增量中的减张技术,以期为临床提供参考。

数字化技术在口腔种植骨增量中的应用及研究进展

种植区牙槽骨骨量不足是影响口腔种植效果的重要因素,骨增量是解决这一问题的有效途径。数字化技术的应用为口腔种植骨增量提供了新手段。本文就数字化技术在口腔种植骨增量中的应用和研究进展进行简要阐述。

下颌后牙区垂直骨量不足的解决方案

下颌后牙区垂直向骨增量技术敏感性高、并发症多,选择何种技术国内外均没有达成共识,关于垂直骨增量后种植修复体的长期效果缺乏大样本量、高质量的临床研究。本文系统性回顾了各种垂直骨增量技术的并发症和长期效果,结合作者多年的临床经验提出了临床术式选择建议,为临床决策提供了参考依据。

“改良”上颌窦底提升

上颌后牙缺失时,由于缺乏牙的功能性刺激以及上颌窦气化作用导致种植所需的剩余骨高度不足,剩余骨量无法保证种植体的初始稳定性时,需要采取上颌窦底提升增加上颌后牙区骨量。“改良”上颌窦底内提升是通过使用富血小板纤维蛋白(platelet-rich fibrin,PRF),在内镜(endoscope)辅助下实现同期植入种植体(simultaneous implants placement)的一种改良的、微创的牙槽嵴入路上颌窦底提升(sinus floor elevation),简称“PESS”。“PESS”在一定程度上优化了上颌窦底提升,减小了手术创伤。本文阐述了“PESS”的原理、适应证、临床操作流程及注意事项,以期为“PESS”在临床中的应用提供技术支持。

“以稳定为核心”的牙槽骨修复重建治疗新技术

经过40余年临床应用与不断发展,引导骨组织再生术(guided bone regeneration,GBR)已被证明是一种可靠的牙槽骨骨增量技术。GBR技术在应用过程中的核心要素是充足的血供和稳定的环境。但现有GBR技术都是在“以血供为核心”的理论体系下进行的,缺乏对稳定要素重要性的重视。我们通过文献阅读及系列临床试验,提出“以稳定为核心”的牙槽骨修复重建理念。基于新理念,创建了以单纯人工骨粉修复牙槽骨重度缺损的治疗新术式,革新了国际上必须用自体骨修复骨缺损的治疗理念。本文将从GBR技术的历史发展轨迹中寻找稳定的重要性,结合现有骨再生理论,详细阐述“以稳定为核心”的牙槽骨修复重建治疗新技术。

生物材料在上颌窦内提升术中的临床应用进展

上颌后牙区常因缺牙后牙槽骨吸收或上颌窦气化导致剩余骨量不足,造成种植修复困难,上颌窦内提升术作为其解决方案之一也在一定程度上受到骨量限制。随着材料学的发展,包括自体骨、同种异体骨、异种骨、合成骨移植材料等骨增量材料以及血小板浓缩物等骨移植辅助材料在医学领域逐渐广泛应用,上颌窦内提升术的适应证得到进一步扩大。将两种或几种材料复合使用或研发复合型材料以实现多种材料性能的互补可能是未来的发展趋势,既能兼顾各种材料的特点,达到更好的成骨效果,还能缩短成骨时间。

计算机辅助设计和计算机辅助制造预成个性化同种异体骨块在种植骨增量手术中的应用进展

计算机辅助设计和计算机辅助制造(CAD/CAM)成形技术可以预成与受区更匹配的目标骨块,目前常应用于复杂的牙槽嵴增量术,通过数字化设计生产个性化的同种异体骨块,避免了传统椅旁骨块成形的步骤,大大增加了临床操作效率,提高了移植物适应的精度,利于移植物的血管化和骨整合,在未来骨增量的临床应用中前景可期。因此,本文就CAD/CAM预成个性化同种异体骨块(CABB)在当前种植骨增量手术的应用现状进行综述,并进一步探讨其存在的问题和挑战。

黏性骨在口腔临床治疗中的应用研究进展

在口腔医学领域中,黏性骨(sticky bone)一般指由第二代血浆基质制品可注射型富血小板纤维蛋白(injectable platelet rich fibrin,i-PRF)与一定质量的骨增量材料(bone grafting materials)混合制备而成的凝胶团块状骨移植物。黏性骨既富含血浆基质所提供的生长因子和纤维蛋白支架等组织再生所需基本要素,又具备一定的可塑性,在骨增量、上颌窦底提升和牙槽嵴保存等临床治疗中有着广阔的应用前景。本文总结临床经验和相关研究,对黏性骨的基本情况和目前在临床治疗中应用作一介绍,以期为后续研究提供参考。

下颌舌侧减张技术在骨增量中的应用研究进展

骨增量技术是解决种植位点牙槽嵴高度和宽度不足的有效方法,术区稳定无张力一期愈合是保证复杂骨增量手术成功的关键。下颌舌侧减张技术近年来逐渐在临床应用,在颊侧减张的基础上该技术能进一步降低组织瓣张力,维护术区稳定性,提升手术成功率。本文就下颌舌侧重要解剖结构、常用减张器械及下颌舌侧减张术式的临床应用作一综述。