在移植骨上延期种植的实验研究

目的论证冷冻自体下颌骨复合髂骨移植后延期种植的可行性。方法16只成年雄性杂种狗，制备下颌骨双侧骨缺损，左侧行冷冻自体下颌骨骨块的原位再植并结合髂骨松质骨移植，即复合移植组（composite transplantation group，CTG），右侧缺损行自体髂骨块移植即髂骨移植组（iliac transplantation group，ITG），术后3个月分别在两类骨块上植入IMZ TPS种植体，种植体植入后3、6、9、12周分别处死4只动物取材，采用数字化X线片对种植体与颌骨结合界面进行灰度定量分析，组织学观察种植体．骨结合情况。结果各期种植体周围均未见吸收性骨质密度减低影像。骨一种植体界面灰度定量分析显示，种植体植入两类移植骨3、6和9周时，其界面骨质密度改变差别明显，复合移植组明显优于髂骨移植组；种植体植入12周时，两组界面骨质已无明显差别，两类移植骨均与种植体有良好的骨结合，其骨愈合方式基本相同。结论冷冻自体下颌骨复合移植修复下颌骨缺损并延期植入牙种植体后，二者可形成良好的骨结合。     

PRP及PRP/OAM对种植体周围骨缺损修复的实验研究

目的探讨富血小板血浆(PRP)以及PRP复合骨诱导活性材料(PRP/OAM)对种植体周围骨缺损修复的作用。方法选取成年Beagle犬4只,体质量10~13 kg,每只犬左右两侧下颌第四前磨牙牙位随机分为A组和B组,与B组同侧的第一、二前磨牙牙位作为对照组。A组种植体周围骨缺损区植入PRP/OAM,B组植入PRP/磷酸三钙,对照组植入磷酸三钙。采用能谱分析各组种植体-新骨界面Ca~(2+)含量,同时观察各组种植术后8、16周组织学形态。结果 A组和B组种植术后8、16周时种植体部位骨表面Ca~(2+)含量均明显高于对照组(P<0.05);A组种植术后8、16周时种植体部位骨表面Ca~(2+)含量为(26.01±3.28)%和(44.10±7.11)%,明显高于B组(P<0.05);种植术后8周,A组新骨与种植体形成区段性骨结合,B组种植体边缘可有新骨形成,对照组种植体边缘为纤维性界面;种植术后16周,A组和B组新骨与种植体形成骨整合,对照组仅为纤维性结合。结论 PRP及PRP/OAM在种植体周围骨缺损修复中,能有效促进骨缺损修复。     

VEGF和TGF-β1促进非血管化骨移植同期种植骨结合的实验研究

目的:探讨外源性VEGF和TGF-β1对非血管化骨移植同期种植的影响。方法:选用实验犬24只(术前1个月拔除双侧下颌前磨牙),随机分为A、B 2组。选取左侧下颌骨造成2.5 cm全层骨缺损,植入同样大小的全层自体髂骨,钛板固定(髂骨块离体时间控制在20 min以内)。A组(12只)移植髂骨块内植入1枚钛种植体。B组(12只)将钛种植体与rhVEGF165和rhTGF-β1复合后再同法植入移植髂骨内。在所有实验犬的右侧下颌无牙区植入1枚种植体作为对照。术后1、2、4个月取材,行X线、组织学、显微CT观察和种植体骨结合力测试。结果:术后1、2个月B组种植体骨接触率较A组显著增高;对种植体周围骨小梁的显微CT分析表明,B组的成骨的作用较A组明显增强。术后4个月,A、B 2组BIC达到60%以上,种植体骨界面结合力接近220 N,已形成较好的骨结合。结论:VEGF和TGF-β1对NVBG同期种植体骨结合早期(术后1～2个月)有明显的促进作用。NVBG同期种植体在术后4个月可以进行上部义齿修复。     

倍骼生与牙内骨内种植体植入修复牙周骨缺损的实验研究

目的 评价倍骼生(PerioGlas)与牙内骨内种植体复合应用于牙周组织再生的疗效.方法 在兔第二前磨牙区制备牙周骨缺损,翻瓣后去除部分牙周骨质及牙周纤维.缺损处分别植入倍骼生与牙内骨内种植体组(A组)、倍骼生组(B组),以常规翻瓣手术组(C组)为对照.术后4周取材做组织学观察和评价.结果 两实验组均有明显新附着形成,其中A组有大量新生牙周组织生长,B组新生组织量较A组少,C组新生组织量很少.结论 倍骼生具有较强骨引导、骨激发作用,牙内骨内种植体植入可稳定患牙,二者联合可有效地提高牙周组织再生.     

富血小板血浆在种植体周围骨缺损修复中的实验研究

目的:探讨富血小板血浆(platelet-richplasma,PRP)、PRP复合骨诱导活性材料(osteoinduction active material,OAM)对种植体周围骨缺损修复的作用。方法:Beagle犬4只,拔除每只犬一侧下颌第一、二前磨牙及其双侧下颌第四前磨牙作为实验牙位。3个月后拔牙处植入种植体,每只犬共植入3颗种植体,第一、二前磨牙牙位植入1颗种植体为对照组,对侧第四前磨牙牙位植入1颗种植体为实验A组,同侧第四前磨牙牙位植入1颗种植体为实验B组。种植术中同期制备种植体周围骨缺损并植入相应骨移植材料:A组植入PRP/OAM;B组植入PRP/磷酸三钙;对照组植入磷酸三钙。种植术后8、16周处死动物,进行组织学观察,测量种植体周围骨密度,采用SPSS13.0软件对数据进行单因素方差分析。结果:8周时,实验A组新骨与种植体形成区段性骨结合;实验B组种植体边缘可见新骨形成,但量较少;对照组种植体边缘为纤维性界面。8周时骨密度测量,各组间骨密度差异无统计学意义。16周时,实验A组可见哈佛系统,实验A、B组新骨与种植体形成骨整合;对照组仅为纤维性结合。16周时骨密度测量,两实验组骨密度均显著高于对照组。结论:PRP及PRP/OAM可促进种植体周围骨缺损修复。     

富含血小板血浆配合骨粉技术在上颌窦外提升术的应用

目的 PRP(富含血小板血浆)配合骨粉促进骨生长及种植体-骨结合,解决上颌磨牙缺损且牙槽嵴高度或厚度不足的问题。方法取38例患者76颗种植体,术中将Bio-oss骨粉和PRP混合物充填在种植体周围骨缺损区,通过术后4²4周口腔曲面断层X线片,评价PRP在种植体周围骨缺损中骨组织再生中的临床效果。结果术后424周口腔曲面断层X线片,评价PRP在种植体周围骨缺损中骨组织再生中的临床效果。结果术后4²4周观察发现骨缺损区都获得了高质量的新骨形成,38例病患种植体无一脱落,跟踪调查种植体3年内存活率达到100%。结论 PRP(富含血小板血浆)配合骨粉可以促进骨组织的再生与修复,促进种植体骨结合,缩短种植体骨结合时间。     

骨诱导活性材料复合富血小板血浆修复犬种植体周围骨缺损

目的从组织学角度评价骨诱导活性材料(osteoinduction active material,OAM)复合富血小板血浆(platelet-rich plas-ma,PRP)对种植体周围骨缺损的修复效果。方法Beagle犬4只,拔除下颌1、2、4前磨牙。每只犬左右两侧实验牙位随机分为实验侧和对照侧,实验侧第4前磨牙牙位为实验A组,第1、2前磨牙牙位为实验B组,对照侧第1、2前磨牙牙位为对照组。3个月后植入种植体,制备种植体周围骨缺损。实验A组骨缺损区植入OAM/PRP;B组植入OAM;对照组植入磷酸三钙。8、16周分别处死动物2只,进行组织学观察,能谱分析种植体-新骨界面Ca含量。结果8周时,A、B组新骨与种植体形成区段性骨结合,对照组种植体边缘为纤维性界面。各组间种植体-新骨界面Ca含量存在显著性差异。16周时,实验A、B组可见哈佛氏系统,新骨与种植体形成骨整合,对照组为纤维性结合。实验各组Ca含量均显著高于对照组。结论OAM及PRP/OAM能促进种植体周围骨缺损修复。     

不同骨移植材料应用于犬拔牙位点保存的实验研究

目的 探究不同比例松质骨、皮质骨混合的同种异体骨、去蛋白牛骨矿物质(DBBM)在位点保存中的牙槽嵴保存效果及对种植体骨结合的影响.方法 拔除两只比格犬双侧第二、三、四前磨牙,12个牙位,随机分为A、B、C、D 4组.A组空白组;B、C、D 3组分别填塞松质骨:皮质骨:脱钙骨基质(DBM)质量比分别为0:9:1和3:6:1的同种异体骨1、同种异体骨2和DBBM.位点保存术后3个月在每个牙位的远中根牙槽窝中央环钻取柱状骨,植入种植体.比较位点保存术后3、6个月拔牙窝高度和宽度的变化.通过组织学分析柱状骨标本的新生骨、剩余材料和结缔组织及其他成分的比例.种植体植入3个月后通过Van?Gieson染色,观察种植体周围骨结合.结果 术后3、6个月各组的颊侧牙槽嵴高度、宽度均降低,经方差分析4组间差异有统计学意义(P<0.05),组间两两比较,A组与其他3组相比差异有统计学意义(P<0.05).位点保存术后3个月,各组新生骨比例差异无统计学意义.A组的种植体骨结合率小于B、C、D组(P<0.05),其余3组间差异无统计学意义.结论 在比格犬的拔牙位点保存术中使用同种异体骨和DBBM均有保存牙槽嵴形态的作用,也对后期种植体骨结合有积极作用.     

CGF与Bio-Oss骨颗粒联合使用在即刻种植中的应用

目的:探讨浓缩生长因子(CGF)联合Bio-Oss骨颗粒在即刻种植修复骨缺损重建治疗中的应用效果。方法:选取在本院行种植修复患者40例,根据治疗方法的不同分为两组：A组(20例)植入Bio-Oss骨粉,覆盖Bio-Guide生物膜,B组(20例)植入CGF与Bio-Oss骨粉的混合物,盖Bio-Guide生物膜。对比两组种植体边缘骨水平(MBL)吸收量、美学效果、种植体稳定性、伤口愈合情况、术后疼痛等。结果:与A组相比,B组术后6个月颊腭侧、近远位点MBL吸收量均更低(P<0.05)。两组术后6个月PES评分比较差异明显,B组近远中龈乳头、唇侧牙龈线、软组织颜色、轮廓、质地及牙槽突外形评分及PES总分均比A组高(P<0.05)。B组伤口愈合时间短于A组,伤口Ⅰ期愈合占比高于A组(P<0.05)。两组术后即刻ISQ值比较,差异无统计学意义(P>0.05);负载6个月ISQ值均高于术后即刻,B组负载6个月ISQ值较A组高(P<0.05)。两组术后1 d、7 d的VAS评分接近(P>0.05);B组术后3 d的VAS评分较A组更低(P<0.05)。A...     

骨髓浓缩物（BMAC）对牙种植体周成骨结构影响的显微影像学分析

目的：利用Micro－CT图像分析骨髓浓缩物（BoneMarrowAspirateConcentrate,BMAC）对牙种植体周骨缺损的成骨结构影响。方法：选用健康成年杂种犬6只,拔除每只犬双侧下颌第三和第四前磨牙（P3和P4）作为实验牙位。3个月后在每只犬拔牙处植入4颗种植体,同期在种植体近中造箱状骨缺损,选2处骨缺损移植骨髓浓缩物（BMAC组）,另2处分别移植自体牙槽骨（AB组）和空白明胶海绵（对照组）。术后第4、12周各处死3只实验犬,标本行Micr0－CT扫描重建,分析缺损区内的骨形态学参数。结果：植入后第4周,骨髓浓缩物组（BMAC组）和自体牙槽骨组（AB组）的Tb．Sp值低于对照组,有统计学意义（P〈0．05）。结论：骨髓浓缩物可以缩短骨再生时间,术后第4周成骨质量优于自体牙槽骨;Micro－CT可有效分析种植体周围骨小梁空间结构。     

牙种植术钻孔骨碎作植骨的临床研究

目的:评价在牙种植术中,钻备种植窝时收集到的自体骨颗粒单独或与Bio-Oss人工骨混合作为骨移植材料应用的临床效果。方法:34例52枚牙种植术的病例分成四组。第一组(对照组)22枚植体,单纯植入种植体,种植区无植入自体骨或人工骨。第二组6枚植体,植入螺纹种植体后,在部分暴露的植体处植入Bio-Oss人工骨。第三组8枚植体,收集种植术中准备植体窝时,在各种钻针上的自体骨颗粒,植入种植体周骨量不足区域。第四组16枚植体,自各种钻针上收集到的自体骨颗粒与Bio-Oss人工骨混合,植入种植体周骨缺损区。记录I、II期手术种植体周围骨组织高度。结果:植入术后3-12个月,II期手术时,实验组有新生骨形成,第四组(即Bio-Oss人工骨与自体骨颗粒混合物植入组),新生骨形成的量较其余组别多。结论:研究表明牙种植术中钻备种植窝时收集到的自体骨颗粒可作为有效的植骨材料,这种简单的方法避免从他处手术获得自体骨,对扩大牙种植适应症有重要意义。RRRR     

A Prospective Study Involving the Use of Platelet Rich Plasma in Enhancing the Uptake of Bone Grafts in the Oral and Maxillofacial Region

Abstract

Platelet-rich plasma (PRP) is an autologous product that contains highly concentrated number of platelets in a small volume of plasma, derived from whole blood by gradient density centrifugation. It has been speculated that local growth factors in human platelets (insulin-like growth factor, IGF; transforming growth factor, TGF-β; platelet derived growth factor, PDGF) would enhance healing of grafts and also counteract resorption. The aim of this study was to evaluate efficacy of PRP on early healing after autogenous bone grafting. Of the twenty patients selected ten were treated with autogenous bone graft and PRP (PRP group) and other ten with autogenous bone graft alone (non-PRP group). PRP group consisted of two benign tumor of mandible, one post surgical defect, two unilateral alveolar cleft, one bilateral alveolar cleft with skeletal class III malocclusion, one maxillary hypoplasia, one oronasal fistula, one recurrent tumor of mandible, one multiple impacted mandibular teeth. Non-PRP group consisted of seven benign tumor of jaw, one keratocyst odontogenic tumor, one orbital blow out fracture, one residual traumatic defect. Biopsies were taken in the native bone, PRP treated grafted bone, grafted bone without PRP at 3 months to assess the maturity of bone. Radiographic imaging was performed by panoramic radiography at 3 and 6 months to evaluate bone opacity of grafted bone on comparison with native bone and computerized tomography at 6 months to evaluate grafted bone morphologically and to measure bone density in Hounsfield units. Microscopic results showed that significantly more matured bone was formed at PRP treated sites as that of native bone and immature bone in controls after 3 months of healing. Bone opacity of PRP treated bone grafts was close to that of native bone than that of non-PRP treated bone grafts on panoramic radiograph at 3 and 6 months. There was graft loss in three cases and graft resorption in one case of non-PRP treated bone grafts at 6 months. In PRP group the compact bone was clearly differentiated from cancellous bone as in native bone and thick in five cases, thin in five cases. In non-PRP group the compact bone was thin as a whole. Comparing native bone group and PRP group the CT value of PRP treated bone graft was more or less close to native bone group and comparing native bone group and non-PRP group CT value was low in non-PRP treated bone graft. Whereas when comparing PRP and non-PRP group CT value was higher in PRP group. Autologous PRP was a safe, biocompatible, effective, source for growth factors and carries no risk of transmissible diseases. It enhances and accelerates bone regeneration of autogenous bone grafts.     

Osseointegration of Osseotite and machined titanium implants in autogenous bone graft. A histologic and histomorphometric study in dogs

It has been shown that a roughened implant surface results in a higher percentage of bone to implant contact (%BIC) than a machined one. A modified implant surface using a dual thermo-acid etching process (Osseotite) has been introduced and evaluated clinically, mechanically and histologically. The aim of the present study was the histological evaluation of the %BIC between the Osseotite or machined surfaces and the autogenous bone graft. Twenty-two custom-made split-type 10-mm-long implants having two opposing surfaces (Osseotite and machined) were placed between the cranial and caudal dorsal iliac spine at the iliac wing of two adult mongrel dogs. An artificial bone defect was created leaving a 2 mm empty space around the coronal 5 mm of the implants, while the apical 5 mm was stabilized in the existing basal bone. The defects around the implants were filled with particulate autogenous bone graft, covered by an Osseoquest membrane, and left to heal for 5 months. All inserted implants showed a complete integration in the bone tissue. It was found that the resulting %BIC at the Osseotite surface was significantly higher than at the machined one in both regenerated (46.44+/-15.81% vs. 28.59+/-12.04%) and basal bone areas (32.32+/-15.09% vs. 17.25+/-7.40%). The findings of this study imply that the use of autogenous bone graft resulted in significantly higher %BIC values in the regenerated area than in the basal bone area itself, for both implant surfaces.     

富含血小板血浆＋骨粉在骨缺损修复中的对比研究

目的：探讨天博（珊瑚转化型羟基磷灰石CHA）和Cerasorb（羟基磷酸三钙β-TCP）两种骨粉单独及分别联合富含血小板血浆（PRP）对骨缺损再生修复效果研究。方法：选用15只成年雄性新西兰大白兔,随机分为三组,全麻下在距下颌骨下缘3mm,下颌角前缘5mm处,用球钻制备大小约15mmx6mmx4mm的缺损,左右侧缺损中各植入A PRP CHA＋PRP;B PRPβ-TCP＋PRP;C CHA＋PRPβ-TCP＋PRP;D CHA CHA＋PRP;Eβ-TCPβ-TCP＋PRP,三组兔子分别饲养4周,8周,12周。并在术后第1周,第3周,第5周分别给予钙黄绿素（10mg/kg）,茜素红（30mg/kg）,钙黄绿素（10mg/kg）处死后进行组织切片观察及骨密度测量,分析结果,SPSS17.0统计软件进行统计分析,以P小于0.05为有显著差异性。结果：组织学检查：4周时,PRP组、CHA组及β-TCP组只有极少量的成骨细胞;8周时,少量的新生骨的生成,但仍有大部分的纤维组织包绕;12周时,有部分成熟骨出现;4周时,CHA＋PRP组及β-TCP＋PRP组开始有成骨细胞及少量未成熟的骨质出现;8周时开始有部分成熟骨出现,成骨细胞核固缩多见;12周时已基本充满成熟骨质。在4、8、12周时,X线上骨缺损区密度百分比分析值PRP组、CHA组及β-TCP组之间无显著差异,而β-TCP＋PRP组及CHA＋PRP组的分析值高于上述三组,但该两组间无明显差异。HE染色的骨定量分析,PRP组、CHA组及β-TCP组之间骨再生情况无显著差异,而两混合组的骨再生值高于上述三组,但该两组间的骨再生无显著差异。结论：1.PRP与骨粉联合应用较PRP单独应用对骨缺损再生效果好。2.β-磷酸三钙联合PRP较羟基磷灰石联合PRP应用对骨缺损再生效果无明显差异。3.β-磷酸三钙与PRP联合应用较β-磷酸三钙单独应用对骨缺损再生效果好。     

Efficacy of PRP in the Reconstruction of Mandibular Segmental Defects Using Iliac Bone Grafts

This retrospective study was conducted to evaluate the role of platelet-rich plasma (PRP) in the reconstruction of segmental mandibular defects using iliac bone grafts. Thirteen patients underwent reconstruction of post-resection segmental defects of the mandible using titanium reconstruction plates, cortico cancellous iliac bone graft. The patients were randomly separated into two groups. One group of the patients received a PRP graft in addition to the iliac bone graft. Post-operative dimensions of the graft were measured and compared to assess the efficacy of PRP in reconstruction of segmental defects. The post-operative follow-up radiographs confirmed consolidation of the graft in all cases and the segmental defect was obliterated. Thereby mandibular continuity was successfully achieved in all cases. Two patients in the non-PRP group developed an infection and were administered additional antibiotics. The infection was contained and the grafts survived. The use of PRP along with autogenous bone graft may be advantageous since it appeared to enhance the quantity of bone formed. Further long-term follow-up and studies are required to effectively establish the efficacy of PRP and autogenous free bone grafts in the reconstruction of bony defects.     

富血小板血浆复合自体松质骨微粒修复兔下颌骨缺损的实验研究

目的探讨富血小板血浆和自体松质骨微粒复合物在颌骨缺损修复中的作用。方法在21只兔双侧下颌骨缺损模型中,按照完全随机化原则,一侧选用富血小板血浆和自体松质骨微粒复合物修复骨缺损,作为实验组;另一侧单纯以松质骨微粒修复,作为对照组。术后2、4、8周,分别处死7只实验动物,分别对标本进行大体、X线摄片、组织病理切片镜下观察。根据Lane—Sandhu骨移植X线片评分标准和骨移植组织学评分法,对X线检查结果和组织学病理切片镜下观察结果进行量化和统计学处理。结果实验组和对照组手术创口均一期愈合。术后不同时期,实验组新生血管的量、新生纤维组织、新生骨质均较对照组多。实验组和对照组评分结果有显著性差异。结论富血小板血浆能够促进颌骨缺损的愈合和成骨;富血小板血浆复合自体松质骨微粒可用于颌骨缺损修复。     

Use of platelet-rich plasma under autogenous onlay bone grafts

OBJECTIVES: To analyze the healing of autogenous onlay bone grafts in three different situations, focusing on the interface area. MATERIAL AND METHODS: Sixteen rabbits underwent autogenous bone graft surgeries in the calvaria. The block bone grafts were positioned in three different situations: direct contact between bone graft and receptor bed, graft interposed by particulate bone, and graft interposed by platelet-rich plasma (PRP). After 7, 15, 30, and 60 days, the specimens were retrieved for histological and morphometric evaluation. RESULTS: All groups healed uneventfully and presented incorporation of the grafts after 30 days. A slightly more evident new bone formation could be observed in the PRP group in the first analyzed period, and an earlier maturation of bone in the last period, although no statistically significant differences were achieved. CONCLUSION: The use of additional material between the bone graft and the receptor bed when using the onlay technique must be carefully considered, taking into account the size of the reconstruction and the cost/benefit relation. The addition of PRP in between autogenous bone blocks and the receptor bed did not confer significant benefit for the new bone formation and healing on the calvaria of bone of rabbits.     

Healing of Fresh Frozen Bone Allograft with or without Platelet‐Rich Plasma: A Histologic and Histometric Study in Rats

Purpose: This study histomorphometrically analyzed the effect of autogenous platelet‐rich plasma (PRP) on healing of fresh frozen bone allograft (FFBA) in bony defects in rat calvaria. Materials and Methods: A 5 mm–diameter defect was created in the calvarium of 30 rats. Animals were divided into three groups: C (defect was filled by blood clot only), FFBA (defect was filled with 0.01 mL of FFBA), and FFBA/PRP (defect was filled with 0.01 mL of FFBA combined with 100 µL of PRP). All animals were euthanized at 30 days postoperatively. Histomorphometry and histology analyses were performed. Data were statistically analyzed (analysis of variance, Tukey, p < .05). Results: FFBA had a statistically smaller new bone area than groups FFBA/PRP and C. No statistically significant differences were observed between groups FFBA and FFBA/PRP with regard to remaining bone graft particle area. Conclusion: It can be concluded that (1) PRP improved the incorporation of FFBA, increasing the amount of new bone formed; (2) PRP has not influenced the resorption of nonviable particles of the FFBA; and (3) presence of remaining FFBA particles might have accounted for the smaller amount of new bone observed in group FFBA when compared with control group.     

Effect of platelet-rich plasma on bone healing of autogenous bone grafts in critical-size defects

Aim: This study histologically analysed the effect of autogenous platelet-rich plasma (PRP), prepared according to a new semiautomatic system, on healing of autogenous bone (AB) grafts placed in surgically created critical-size defects (CSD) in rabbit calvaria.
Material and Methods: Sixty rabbits were divided into three groups: C, AB and AB/PRP. A CSD was created in the calvarium of each animal. In Group C (control), the defect was filled by blood clot only. In Group AB (autogenous bone graft), the defect was filled with particulate autogenous bone. In Group AB/PRP (autogenous bone graft with platelet-rich plasma), it was filled with particulate autogenous bone combined with PRP. All groups were divided into subgroups ( n =10) and euthanized at 4 or 12 weeks post-operatively. Histometric and histologic analyses were performed. Data were statistically analysed ( anova , t -test, p <0.05).
Results: Group C presented significantly less bone formation compared with Group AB and AB/PRP in both periods of analysis ( p <0.001). At 4 weeks, Group AB/PRP showed a statistically greater amount of bone formation than Group AB (64.44 ± 15.0% versus 46.88 ± 14.15%; p =0.0181). At 12 weeks, no statistically significant differences were observed between Groups AB and AB/PRP (75.0 ± 8.11% versus 77.90 ± 8.13%; p >0.05). It is notable that the amount of new bone formation in Group AB/PRP at 4 weeks was similar to that of Group AB at 12 weeks ( p >0.05).
Conclusion: Within its limitation, the present study has indicated that (i) AB and AB/PRP significantly improved bone formation and (ii) a beneficial effect of PRP was limited to an initial healing period of 4 weeks.     

Stability Evaluation of Implants Integrated in Grafted and Nongrafted Maxillary Bone: A Clinical Study from Implant Placement to Abutment Connection

Background: Clinical studies have shown a higher degree of implant failures in grafted bone compared with normal nongrafted maxillary bone. Additionally, a prolonged time for integration of titanium implants in grafted block bone has been shown by means of resonance frequency analysis (RFA). Purpose: The aim of this prospective study was to compare the stability of implants placed in particulate bone, onlay block bone, interpositional bone, and nongrafted maxillary bone during the early phase of osseointegration using RFA and implant failure. Material and Methods: Thirty‐five patients with edentulism in the maxilla were included in the study. In all, 260 Astra Tech TiOblast? implants (Astra Tech AB, Mölndal, Sweden) were installed. Twenty‐five of these patients had severe maxillary atrophy and were treated with iliac bone grafts 5 to 6 months prior to implant placement, 19 with lateral onlay block grafts on one side (group A, 38 implants) and particulate bone for lateral augmentation on the other (group B, 38 implants). These 19 patients also got bilateral sinus floor augmentation with particulate bone (group C, 76 implants). Six patients had an unfavorable sagittal relation between the jaws and underwent a LeFort I operation with interpositional bone blocks grafted to the nasal and sinus floors (group D, 48 implants). The remaining 10 patients could be treated with implants without bone augmentation and served as control (group E, 60 implants). RFA was performed at implant placement and abutment connection 6 months later and an implant stability quotient (ISQ) value was given for each implant. Results: Four implants (1.5%) were found mobile at abutment connection and removed (two in group A and two in group D). RFA showed a slight increase in stability from installation to abutment connection but the differences were not statistically significant in any of the groups (Wilcoxon signed rank test for comparison of paired data). Implants installed in group D had a significantly lower ISQ value at both measurements compared with the other groups (Wilcoxon Rank Sum test for comparisons of independent samples, p = .05). Conclusion: It is concluded that TiO₂‐blasted implants placed in nongrafted and grafted maxillary bone using a two‐staged protocol show similar stability during the early phase of osseointegration. Patients reconstructed with interpositional bone graft after a LeFort I osteotomy showed lower implant stability values than nongrafted patients and other grafting techniques.