Early therapeutic effect of platelet-rich fibrin combined with allogeneic bone marrow-derived stem cells on rats’ critical-sized mandibular defects

BACKGROUND Critically sized bone defects represent a significant challenge to orthopaedic surgeons worldwide.These defects generally result from severe trauma or resection of a whole large tumour.Autologous bone grafts are the current gold standard for the reconstruction of such defects.However,due to increased patient morbidity and the need for a second operative site,other lines of treatment should be introduced.To find alternative unconventional therapies to manage such defects,bone tissue engineering using a combination of suitable bioactive factors,cells,and biocompatible scaffolds offers a promising new approach for bone regeneration.AIM To evaluate the healing capacity of platelet-rich fibrin(PRF)membranes seeded with allogeneic mesenchymal bone marrow-derived stem cells(BMSCs)on critically sized mandibular defects in a rat model.METHODS Sixty-three Sprague Dawley rats were subjected to bilateral bone defects of critical size in the mandibles created by a 5-mm diameter trephine bur.Rats were allocated to three equal groups of 21 rats each.Group I bone defects were irrigated with normal saline and designed as negative controls.Defects of group II were grafted with PRF membranes and served as positive controls,while defects of group III were grafted with PRF membranes seeded with allogeneic BMSCs.Seven rats from each group were killed at 1,2 and 4 wk.The mandibles were dissected and prepared for routine haematoxylin and eosin(HE)staining,Masson's trichrome staining and CD68 immunohistochemical staining.RESULTS Four weeks postoperatively,the percentage area of newly formed bone was significantly higher in group III(0.88±0.02)than in groups I(0.02±0.00)and II(0.60±0.02).The amount of granulation tissue formation was lower in group III(0.12±0.02)than in groups I(0.20±0.02)and II(0.40±0.02).The number of inflammatory cells was lower in group III(0.29±0.03)than in groups I(4.82±0.08)and II(3.09±0.07).CONCLUSION Bone regenerative quality of critically sized mandibular bone defects in rats was better promoted by PRF membranes seeded with BMSCs than with PRF membranes alone.

Repair of oral mandibular defects with rib composite flap pedicled with internal thoracic

Objective To study feasibility and value of repair of oral mandibular defects with rib composite flap pedicled with internal thoracic vessels in basic level hospitals. Methods The clinical materials in 13 cases uith mandibular defects which were repaired with rib compos-

Healing Mechanism and Osteogenic Capacity of Bovine Bone Mineral—Human Amniotic Mesenchymal Stem Celland Autogenous Bone Graft in Critical Size Mandibular Defect

Experiments on maxillofacial bone tissue engineering showed the promising result;however, its healing mechanisms and effectiveness had not been fully understood. The aim of this study is to compare the bone healing mechanism and osteogenic capacity between bovine bone mineral loaded with hAMSC and autogenous bone graft in the reconstruction of critical size mandibular bone defect. Critical size defects were made at the mandible of 45 New Zealand white rabbits reconstructed with BBM-hAMSC, BBM alone, and ABG, respectively. At the end of first, second, and twelfth weeks, five rabbits from each experimental week were sacrificed for histology and immunohistochemistry staining. Expressions of vascular endothelial growth factor (VEGF), bone mor-phogenic proteins-2 (BMP2), Runx2 and the amount of angiogenesis were analyzed in the first and second week groups, while expressions of Runx2, osteocalcin, collagen type-I fibres, trabecular area and bone incorporation were analyzed in the twelfth week groups. The result showed that expressions of VEGF, BMP2 and Runx2 as well as the amount of angiogenesis were higher in ABG compared with BBM-hAMSC group in the first and second weeks of healing. The result of twelfth week of healing showed that expressions of Runx2 and osteocalcin as well as the thickness of collagen type-I fibres were significantly higher in BBM-hAMSC compared to ABG group, while there was no statistically difference in trabecular area and bone incorporation between BBM-hAMSC and ABG group. This study concluded that early healing activities were higher in auto-genous bone graft than in BBM-hAMSC, while osteogenic activities in the late stage of healing were higher in BBM-hAMSC compared to autogenous bone graft. It was also concluded that the osteo-genic capacity of BBM-hAMSC was comparable to autogenous bone graft in the reconstruction of critical size defect in the mandible.

Digital design of scaffold for mandibular defect repair based on tissue engineering

Mandibular defect occurs more frequently in recent years,and clinical repair operations via bone transplantation are difficult to be further improved due to some intrinsic flaws.Tissue engineering,which is a hot research field of biomedical engineering,provides a new direction for mandibular defect repair.As the basis and key part of tissue engineering,scaffolds have been widely and deeply studied in regards to the basic theory,as well as the principle of biomaterial,structure,design,and fabrication method.However,little research is targeted at tissue regeneration for clinic repair operations.Since mandibular bone has a special structure,rather than uniform and regular structure in existing studies,a methodology based on tissue engineering is proposed for mandibular defect repair in this paper.Key steps regarding scaffold digital design,such as external shape design and internal microstructure design directly based on triangular meshes are discussed in detail.By analyzing the theoretical model and the measured data from the test parts fabricated by rapid prototyping,the feasibility and effectiveness of the proposed methodology are properly verified.More works about mechanical and biological improvements need to be done to promote its clinical application in future.

Study on repairing canine mandibular defect with porous Mg-Sr alloy combined with Mg-Sr alloy membrane

To discuss the feasibility of the application of porous Mg-Sr alloy combined with Mg-Sr alloy membrane in the repair of mandibular defects in dogs.The second and third mandibular premolars on both sides were extracted from six dogs.The model of mandible buccal fenestration bone defects were prepared after the sockets healed.Twelve bone defects were randomly divided into groups A and B,then Mg-Sr alloy was implanted in bone defects of group A and covered by Mg-Sr alloy membrane while Mg-Sr alloy was implanted in bone defects of group B and covered by mineralized collagen membrane.Bone defects observed on cone beam computed tomographic images and comparing the gray value of the two groups after 4,8 and 12 weeks.After 12 weeks,the healing of bone defects were evaluated by gross observation,X-ray microscopes and histological observation of hard tissue.Bone defects in each group were repaired.At 8 and 12 weeks,the gray value of group A was higher than that of group B(P<0.05).At 12 weeks,the bone volume fraction of group A was higher than that of group B(P<0.05).The newly woven bone in group A is thick and arranged staggered,which was better than that of group B.Porous Mg-Sr alloy combined with Mg-Sr alloy membrane could further promote the repair of mandibular defects,and obtain good osteogenic effect.

Three-dimensional printed tissue engineered bone for canine mandibular defects

Background:Three-dimensional(3D)printed tissue engineered bone was used to repair the bone tissue defects in the oral and maxillofacial(OMF)region of experimental dogs.Material and methods:Canine bone marrow stromal cells(BMSCs)were obtained from 9 male Beagle dogs and in vitro cultured for osteogenic differentiation.The OMF region was scanned for 3D printed surgical guide plate and mold by ProJet1200 high-precision printer using implant materials followed sintering at 1250℃.The tissue engineered bones was co-cultured with BASCs for 2 or 8 d.The cell scaffold composite was placed in the defects and fixed in 9 dogs in 3 groups.Postoperative CT and/or micro-CT scans were performed to observe the osteogenesis and material degradation.Results:BMSCs were cultured with osteogenic differentiation in the second generation(P2).The nanoporous hydroxyapatite implant was made using the 3D printing mold with the white porous structure and the hard texture.BMSCs with osteogenic induction were densely covered with the surface of the material after co-culture and ECM was secreted to form calcium-like crystal nodules.The effect of the tissue engineered bone on the in vivo osteogenesis ability was no significant difference between 2 d and 8 d of the compositing time.Conclusions:The tissue-engineered bone was constructed by 3D printing mold and hightemperature sintering to produce nanoporous hydroxyapatite scaffolds,which repair in situ bone defects in experimental dogs.The time of compositing for tissue engineered bone was reduced from 8 d to 2 d without the in vivo effect.

A novel conceptual design of a biomimetic oral implant and its biomechanical effect on the repairment of a large mandibular defect

This study aimed to propose a novel biomimetic design strategy of an oral implant and to numerically examine its biomechanical effect according to clinical interests.The designed implant conceptually mimicked the morphology and elastic modulus of the mandibular bone.Basing on a CT-image-based patient-specific reconstruction of the tumor-excised mandible,the biomechanical effects of the implants with three materials(PEEK/n-HA/CF,PEEK/HA and Ti6Al4V),two surgical conditions(removed and retained muscles),and two postoperative stages(early and late)were fully investigated by a static finite element analysis.Moreover,according to clinical interests(e.g.failure and stability of the implant and rivets),maximum von Mises stresses and strains of the implant and rivets,maximum implant-bone gap in the early postoperative stage,and maximum von Mises stress of the mandible were mainly analyzed.The results showed that the implant composed of Ti6Al4V material was suitable for the current design strategy with respect to the other two PEEK-based materials.Although the implants in the muscle-retained surgical condition had relative greater indices compared to the muscle-removed surgical condition,the index difference between the two conditions was slight.The biomechanical indices indicating the failure and loosening risks of implant and rivets were much reduced in the late postoperative stage with respect to the early postoperative stage due to the osteointegration at the implant-bone interface.Generally,the proposed novel design strategy could be useful to guide the design of the oral implant addressing different implant materials and surgical conditions,and further made proper suggestion to clinicians and patients.

下颌骨缺损患者对咬合功能锻炼需求的质性研究

目的:了解口腔肿瘤术后下颌骨缺损患者咬合功能锻炼的现状与需求。方法 :采用目的 抽样法,对27例口腔肿瘤术后下颌骨缺损患者进行半结构式访谈,借鉴扎根理论的三级编码体系,运用Nvivo11质性分析软件进行自下而上的编码分析。结果:下颌骨缺损患者咬合功能锻炼的现状与需求可归纳为5个主题,即下颌骨缺损对患者的影响、咬合功能锻炼相关知识缺乏、对咬合功能锻炼内容的需求(期待专业化健康指导)、对咬合功能锻炼宣教方式的需求(期待多元化宣教方式及各种阻碍因素导致患者依从性降低)。结论 :建立统一规范的咬合功能锻炼方案,临床医护人员应关注患者的各种阻碍因素,调节患者心理状态,最大限度提高患者咬合功能锻炼的依从性。

重度牙周破坏对下颌第一磨牙拔牙后种植手术方式影响的回顾性研究

目的:对下颌第一磨牙拔除后行种植修复的病例进行回顾性研究,探索重度牙周破坏(advanced periodontal defect,APD)对拔牙后种植手术方式的影响。方法:纳入下颌第一磨牙拔除后自然愈合3~12个月行种植手术的患者176例,共179个种植位点,进行回顾性分析,记录患者年龄、性别、缺牙时间以及拔牙时是否有APD。采用多因素Logistic回归,分析拔牙前APD是否是种植时行引导性骨再生(guided bone regeneration,GBR)的风险因素。结果:对年龄、性别、缺牙时间等因素校正后,结果显示,有APD的下颌第一磨牙,种植时行GBR的风险是无APD位点的4.738倍(95%可信区间:1.650~13.609,P<0.05)。结论:APD的下颌第一磨牙拔除后,种植手术时行GBR的可能性更大。

舌下腺瓣修复临床Ⅱ期慢性黄磷性颌骨骨髓炎和药物相关性颌骨坏死术后缺损

目的:探讨利用舌下腺瓣修复临床Ⅱ期慢性黄磷性颌骨骨髓炎(PNJ)和药物相关性颌骨坏死(MRONJ)术后颌骨缺损的临床效果。方法:利用舌下腺瓣修复慢性下颌骨坏死术后颌骨缺损的5例患者。其中慢性黄磷性颌骨骨髓炎3例,药物相关性颌骨坏死患者2例。结果:5例患者临床检查评价治疗效果,术后2周内创口愈合良好,无感染,舌下腺功能正常。结论:利用舌下腺瓣修复慢性黄磷性颌骨骨髓炎和药物相关性颌骨坏死术后下颌骨缺损有效可行。

微血管吻合器在股前外侧皮瓣修复口腔恶性肿瘤术后缺损中的应用效果

目的:通过对比股前外侧皮瓣修复口腔恶性肿瘤术后缺损中血管吻合方法的差异,分析使用微血管吻合器与手工吻合方法对肺部感染的影响,并评估肺部感染相关的危险因素。方法:回顾分析2019年1月—2022年10月在青岛大学附属医院口腔颌面肿瘤外科接受股前外侧皮瓣行下颌骨缺损修复的92例患者,其中吻合器组42例,手工吻合组50例。术后随访12个月,评估术后合并肺部感染的危险因素。采用SPSS 22.0软件包对数据进行统计学分析。结果:吻合器组行单静脉吻合术28例,双静脉吻合术11例,动脉和静脉均吻合3例。54(54/56,96.43%)个吻合器被成功使用进行吻合,2例分别因术中动脉吻合口痉挛、静脉吻合后内径明显缩小而放弃。所有患者均未发生皮瓣失败,皮瓣总成活率为100%。吻合器组与手工吻合组相比,术后肺部感染率虽无统计学差异,但有明显降低趋势。另外在吻合器组,糖尿病与术后白蛋白<30 g/L并非肺部感染的危险因素,而与吸烟、年龄、ACE-27评分显著相关。吻合器的使用有助于降低平均住院日,由平均11.1天降至8.9天。结论:合理的血管吻合器使用具有高的皮瓣成活率且对降低术后肺部感染以及平均住院日有积极作用,但仍需更多的大型随机临床试验进行研究。

下颌骨缺损腓骨肌皮瓣重建后种植义齿修复的临床效果评价

目的:评价下颌骨缺损腓骨肌皮瓣重建后种植义齿修复的临床疗效。方法:纳入15例因肿瘤行下颌骨缺损腓骨肌皮瓣重建后的患者,评价在种植义齿修复后2年种植体的存留率、种植体周探诊深度(PD)、改良龈沟出血指(mSBI)、种植体边缘骨高度(MBL)。结果:62枚种植体在行使功能后2年种植体存留率100%;种植修复2年后,与修复前相比,MBL、PD及mSBI未见统计学差异(P>0.05);PD>4 mm时,mSBI显著增加(P<0.05)。结论:下颌骨缺损腓骨肌皮瓣重建后种植义齿修复取得了良好的临床疗效,PD≤4 mm的种植体表现出更好的稳定性。

基于Micro-CT评价超声骨焊接技术PDLLA材料对骨愈合性能的影响

目的采用微焦点断层扫描(Micro-CT)评价超声骨焊接技术应用过程中超声震荡产热作用下PDLLA材料对骨愈合性能的影响。方法选择SPF级雄性新西兰大白兔36只,随机分为超声骨焊接技术辅助PDLLA材料组(A组)、拧入技术辅助PDLLA材料组(B组)、假手术组(C组)、空白对照组(D组),各9只。于术后4、8、12周取下颌骨标本,周围骨组织进行HE染色,观察各组植入钉周围情况。对术后4、8、12周的下颌骨大体标本拍摄Micro-CT图,使用VG Studio MAX软件进行三维重建,摆正数据样本,即颌骨颊侧造模处为轴向,动态分析植入钉体积、植入钉周围200μm环状区及骨缺损处的植入材料体积数、相对骨体积分数(BV/TV)、骨小梁厚度(Tb.Th)、骨小梁数(Tb.N)、骨小梁间隙(Tb.Sp)等骨愈合相关指标。结果HE染色结果显示,按3个时间可动态观察到A、B、C组骨缺损处骨性骨痂替代纤维性骨痂,形成类骨质,编织骨的过程符合正常骨损伤愈合的过程。Micro-CT结果显示,A、B组术后3个时间点的材料体积比较差异均无统计学意义(P>0.05);在3个时间点,4组植入钉周围200μm环状区中BV/TV、Tb.Th、Tb.N、Tb.Sp比较差异均无统计学意义(P>0.05);在骨缺损处,A、B、C组三个时间点BV/TV、Tb.Th、Tb.N、Tb.Sp比较差异无统计学意义(P>0.05);术后4周,与D组比较,A、B、C组BV/TV、Tb.Th、Tb.N、Tb.Sp差异有统计学意义(P<0.05);与C组比较,A、B组Tb.N差异有统计学意义(P<0.01)。术后8周,与D组比较,A、B、C组BV/TV、Tb.Th、Tb.N、Tb.Sp差异有统计学意义(P<0.05);术后12周,与D组比较,A、B、C组BV/TV、Tb.Th、Tb.Sp差异有统计学意义(P<0.05)。结论超声骨焊接技术其超声震荡产热作用下PDLLA材料对骨愈合性能无不良影响。

同期神经化腓骨瓣用于下颌骨重建及下唇感觉恢复的术式初探

目的:探讨下颌骨及下牙槽神经因肿瘤截除后,同期颌骨重建及感觉恢复的新方法,为临床提供参考。方法:对1例下颌骨成釉细胞瘤患者行下颌骨节段性切除,术中一并切除与病灶密切的下牙槽神经,同期行神经化血管化腓骨游离皮瓣移植修复。术后通过影像学观察其移植骨吸收情况,应用两点辨别觉和感觉测试丝评估感觉保存效果。结果:术后随访9个月,患者颜面自然对称,皮瓣存活良好,移植骨稳定未见明显吸收,下唇感觉功能良好,颏部稍次,无咬唇、流涎等问题;受区及供区未见并发症。结论:同期重建神经的新方法对腓骨瓣移植重建下颌骨时恢复下唇感觉及预防移植骨术后吸收具有较好效果。

聚合瓷高嵌体与全瓷冠在下颌第一磨牙缺损修复中的应用及对咀嚼功能和美学效果的影响

目的:探讨聚合瓷高嵌体与全瓷冠在下颌第一磨牙缺损修复中的应用及对咀嚼功能和美学效果的影响。方法:选取笔者医院2020年1月-2021年12月收治的120例第一磨牙缺损患者作为研究对象,按照随机数字表法分为对照组(60例,采用全瓷冠修复)和观察组(60例,采用聚合瓷高嵌体修复)。观察两组患者的修复效果、牙周健康指标、咀嚼功能、美学效果及不良事件发生情况。结果:治疗后12个月,观察组修复总有效率高于对照组(P<0.05);观察组牙周健康指标评分均低于对照组(P<0.05);观察组咀嚼功能显著高于对照组(P<0.05);观察组患者的表面光滑、边缘密合性、固定良好及颜色匹配评分高于对照组(P<0.05);观察组继发龋、牙冠折裂、牙龈红肿、咬合痛不良事件发生率低于对照组(P<0.05);观察组患者修复成功率及存活率高于对照组(P<0.05)。结论:与全瓷冠治疗比较,应用聚合瓷高嵌体修复下颌第一磨牙缺损能够提高患者远期修复效果,改善牙周健康状况,提升咀嚼功能及美学效果。

全瓷冠修复下颌第二磨牙远中缺损龈壁提升后的美学效果及生物力学性能研究

目的探讨下颌第二磨牙远中缺损龈壁提升后给予全瓷冠修复的美学效果及生物力学性能。方法选择2021年2月至2023年2月我院收治的因第二磨牙远中缺损行龈壁提升后给予全瓷冠修复的40例患者作为观察组,另选40例行龈壁提升后给予金属桩钴铬烤瓷冠修复的第二磨牙远中缺损患者作为对照组。比较两组患者修复后12个月的修复效果和各结构的生物力学性能分布;比较两组修复前及修复后12个月的牙周状况和美学效果评分;采用广义估计方程评价全瓷冠修复对患牙美学效果和生物力学性能的影响;比较两组患者的修复满意度。结果观察组在边缘密合性、颜色匹配、牙龈健康方面的修复成功率明显高于对照组(P<0.05);两组患者修复前的牙龈指数(GI)、牙周探诊深度(PD)、龈沟液(GCF)量、美学效果的主观评分和客观评分差异无统计学意义(P>0.05),两组患者修复后12个月的GI、PD、GCF、主观评分和客观评分较修复前均明显增加,观察组的GI、PD、GCF明显小于对照组,主观评分和客观评分明显高于对照组(P<0.05);观察组修复体、粘接剂、牙本质、牙釉质的垂直向载荷应力、斜向载荷应力较对照组均明显减小(P<0.05);广义估计方程评价结果显示,全瓷冠修复能够减轻对患牙牙周健康状况的影响,生物力学性能较好;观察组修复12个月后修复满意度评价为A级的患者比例明显高于对照组(P<0.05)。结论下颌第二磨牙远中缺损龈壁提升后给予全瓷冠修复能够提高美学效果评分,维持良好的生物力学性能,减轻对患牙牙周健康的影响。

下颌骨节段性缺损腓骨修复重建后分段垂直牵张成骨及种植修复1例报告

目的:报道1例于2020年8月就诊于中国人民解放军联勤保障部队第九二〇医院下颌骨节段性缺损,腓骨修复重建后行分段垂直牵张成骨及牙种植的病例资料。方法:Ⅰ期手术为水平及垂直截开下颌的腓骨瓣,植入内置牵张器,依据牵张成骨原则及种植所需高度完成腓骨分段垂直牵张治疗;Ⅱ期手术为拆除牵张器并植入种植牙。结果:根据影像学检查及术中所见,腓骨分段垂直牵张成骨良好,能够得到良好的骨高度,种植体初期稳定性良好。结论:腓骨瓣分段垂直牵张成骨可作为腓骨瓣修复后提升其骨高度的有效技术。

动态导航引导下下颌骨缺损腓骨瓣移植修复区种植体植入1例报告

腓骨瓣移植修复下颌骨缺损后常采用种植义齿修复缺牙。由于腓骨的截面类似三角形、恢复的骨高度不足及内固定钛钉钛板的存在,以修复为导向在移植腓骨上进行种植体植入成为口腔种植领域的难题。本文对1例腓骨瓣移植修复下颌骨缺损患者在动态导航引导下,在移植腓骨上精准植入4颗种植体以恢复缺牙和咀嚼功能,取得了理想效果。

腓骨重建小钛板及重建板固定下颌骨体部缺损的生物力学比较分析

目的:利用三维有限元方法比较小钛板及重建板固定的下颌骨体部缺损腓骨修复后的应力分布特点及位移情况,为临床上内固定选择提供力学依据。方法:建立下颌骨体部缺损腓骨修复及小型四孔钛板与重建板固定的三维有限元模型,模拟健侧磨牙咬合加载,对比分析钛板、钉孔周围骨质的最大应力值以及腓骨前后端的最大应力值和位移情况。结果:建立了小钛板与重建板固定的下颌骨体部缺损腓骨重建的三维有限元模型。钛板最大应力值均出现在下颌角区域,且均位于钛板上缘或后上方钛板(小钛板组),重建板31.645 MPa,小钛板37.031 MPa,均低于钛合金材料的破坏极限。钉孔周围皮质骨最大应力值均在最靠近前部下颌骨残端与腓骨交界处的第一个钉孔处,重建板4.712 MPa,小钛板8.243 MPa,也都低于皮质骨的屈服强度。总体位移腓骨前端均大于后端且两种钛板组结果相近。结论:重建板和小钛板均能满足下颌骨体部缺损腓骨固定修复的生物力学要求。

下颌骨埋伏阻生第三磨牙拔除术后自然转归及对邻近第二磨牙的影响

目的:观察下颌阻生第三磨牙(impacted mandibular third molars,IM3Ms)拔除术后的自然转归及对邻近下颌第二磨牙(mandibular second molars,M2Ms)的影响。方法:选择下颌第三磨牙骨埋伏阻生的患者34例(51颗IM3Ms),使用超声骨刀、气动涡轮手机拔除患牙,分别于术前、术后1周及术后6个月随访,观察术后反应及M2Ms远中骨缺损情况。比较手术前后M2Ms远中骨缺损深度,并分析其影响因素。采用SPSS 29.0软件包对数据进行统计学分析。结果:术前M2Ms远中骨高度未见明显缺损,但拔除IM3Ms时,由于去骨拔牙等操作产生骨缺损。术后6个月,骨高度虽有所恢复,骨缺损率减少,但未达到术前水平。IM3Ms埋伏阻生深度是恢复率的主要影响因素。探诊深度较术前显著增加。术后24 h内患者疼痛感较重,术后1周缓解,但仍存在轻度开口受限及面部肿胀。拔除IM3Ms对患者日常生活、情绪、工作、睡眠影响较小。结论:下颌第三磨牙拔除术后,邻近第二磨牙远中骨高度部分恢复,但未达到术前水平。拔牙手术中需采取更加精细的手术技巧,以减少对邻近牙和骨组织的影响。同时,拔除IM3Ms后应给予镇痛药物,加强卫生宣教,提高患者术后舒适度。