放疗对纯钛种植体周围骨组织影响的形态学研究

目的 探讨放疗对纯钛种植体周围骨组织的影响。方法 本实验通过兔胫骨骨内植入纯钛植入体与不锈钢植入体建立植入体骨整合的动物模型，并在此基础上进行放疗，标本在光镜和扫描电镜下观察。结果 放疗对纯钛种植体周围骨质影响甚小，而对不锈钢种植体周围骨质影响较大。结论 钛金属具有良好的生物相容性，理化性能好，密度低、放射引发的二次射线损伤小。     

放疗对狗下颌纯钛种植体与骨接触作用的影响

目的:观察放疗对狗下颌纯钛种植体与骨接触作用的影响。方法:8只成年雄性杂种狗,拔除双侧下颌第3、4前磨牙和第1磨牙,形成无牙区。拔牙后3个月,用电子直线加速器照射一侧下颌无牙区,单一剂量15Gy。另一侧不接受照射,作为对照。放疗后3个月,狗双侧下颌无牙区各植入纯钛种植体4枚,其中两枚种植体无任何辅助治疗措施。种植术后1.5个月和3个月分别处死2只动物取材。结果:放疗侧种植体的种植体-骨接触率与对照侧相比,有明显下降,在统计学上有显著差异(P=0.0001<0.01);放疗后种植体周围骨小梁体积百分比具体数值下降,统计学上差异不明显(P=0.071>0.05)。结论:放疗会影响狗下颌纯钛种植体与骨的接触作用。     

放疗对骨组织及种植体周围骨结合影响的研究进展

种植义齿逐渐成为牙列缺损和牙列缺失成年患者的最佳修复方法。对于头颈部恶性肿瘤患者,通常采取手术切除联合放化疗。然而,放疗对机体颌骨组织产生一定的损害,进而间接影响种植体周围的骨结合。本文将主要就放疗对骨组织的影响及放疗对种植体周围骨结合的作用作一综述。     

补肾方剂对骨质疏松大鼠纯钛种植体骨结合影响的骨计量学研究

目的:观察补肾方剂对骨质疏松大鼠纯钛种植体骨结合的影响,探讨补肾方剂促进纯钛种植体骨结合的机制。方法:选用纯种8月龄雌性SD大鼠54只,随机分为3组。A组:假手术组,B组:卵巢切除组,C组:卵巢切除加中药治疗组。在3组大鼠胫骨近中干骺端分别植入纯钛光滑柱状种植体。C组大鼠用补肾方剂灌胃。种植术后1、2、3个月,取出带种植体的胫骨,制作HE染色的组织切片,骨计量学观察。结果:C组的骨小梁宽度、结合骨板宽度、松质骨区骨量、成骨细胞数均明显大于B组(P<0.01)。结论:补肾方剂可以使骨质疏松大鼠种植体周围的成骨细胞数增加,松质骨区骨量明显增加,促进骨改建,提高骨结合的质量。     

局部应用骨形成蛋白与透明质酸钠复合物对放疗后纯钛种植体骨整合作用的影响

1 .实验目的 :①观察放疗对狗下颌种植体周围骨形成蛋白 (ｂｏｎｅｍｏｒｐｈｏｇｅｎｉｃｐｒｏｔｅｉｎ ,ＢＭＰ)分布与活性的影响 ;②观察局部应用ＢＭＰ与透明质酸钠复合物对放疗后纯钛种植体骨整合作用的影响。2 .实验方法 :成年雄性杂种狗 4只 ,体重 2 0～ 2 2ｋｇ,拔除双侧下颌第 3、4前磨牙和第 1磨牙 ,形成无牙区。拔牙后3个月 ,用电子直线加速器照射一侧下颌无牙区 ,单一剂量1 5Ｇｙ。另一侧不接受照射 ,作为对照。放疗后 3个月 ,狗双侧下颌无牙区植入纯钛种植体各 4枚 ,其中每侧各 2枚种植体在局部使用ＢＭＰ与透明质酸钠的复合…     

CDIC和ITI纯钛种植体周围骨组织生物学基础研究

目的：应用MicroCT、光学显微镜评价国产CDIC和ITI纯钛种植系统与周围骨组织整合的差别。方法：拔除狗的第一、第二磨牙,4个月后应用国产CDIC和ITI种植体植入,同体对照,术后4月、12月处死动物,分别取含种植体的组织块,MicroCT成像建立三维模型后,不脱钙切片甲苯胺蓝染色行光学显微镜对比观察。结果：①.两组种植体均被机体耐受,周围的骨组织均未发现炎症细胞和巨大细胞②.MicroCT、光学显微镜观察均显示ITI比CDIC种植体新骨形成早、量多,一年之后两者骨组织形成量没有显著差别。③MicroCT和光学显微镜对种植体周围骨组织微结构的研究结果具有正相关性。结论：使用国产CDIC种植系统与ITI种植系统骨结合基本相同,在临床上能获得较高的成功率。MicroCT分辨率高,能够建立高清晰三维图像,是对种植体周围骨组织研究的一种准确有效的新方法。     

电磁场对商业纯钛种植体周围骨愈合影响的组织学和力学研究

脉冲电磁场(PEMF)已成功用于治疗骨科中的假关节病和不愈合性骨折。一些研究提示：在口腔种植手术后运用脉冲电磁场治疗有利于种植体周围骨愈合。有关PEMF促进骨愈合的机制还未完全阐明，但认为PEMF能促进组织血管化、胶原生成和骨原细胞的增殖分化。迄今为止，几乎所有     

放疗和高压氧辅助治疗对狗下颌纯钛种植体周围骨组织沉积率的影响

目的：观察放疗和高压氧（hyperbaric oxygen，HBO）辅助治疗对狗下颌纯钛种植体周围骨组织沉积率影响。方法：8只成年雄性杂种狗，拔除双侧下颌第三、第四前磨牙和第一磨牙，形成无牙区。拔牙后3个月，用电子直线加速器照射一侧下颌无牙区，单一剂量15Gy。另一侧不接受照射，作为对照。放疗后3个月，狗双侧下颌无牙区植入纯钛种植体各4枚，其中2枚种植体在局部使用骨形成蛋白（bone morphogenetic protein，BMP）与透明质酸钠的复合物。以四环素和二甲酚橙作为荧光标记物，自种植体植入术第一天起注射。放疗后2个月，将8只狗随机分为2组，每组4只。其中1组在种植术前后接受HBO辅助治疗。种植术后1．5个月和3个月分别处死4只动物取材。结果：在1．5个月取材组，沉积率在放疗与非放疗间差别明显（P=0．041〈0．05）；在HBO辅助治疗与无HBO辅助治疗组间有差别（沉积率2 P=0．015〈0．05；沉积率3P=0．041〈0．05）。在3个月取材组，沉积率在HBO辅助治疗与无HBO辅助治疗组间统计学上有明显差别（P=0．002〈0．01）。结论：放疗可以降低种植体周围骨组织的骨沉积率，HBO辅助治疗可以影响放疗后狗下颌种植体周围骨组织的骨沉积率。     

CDIC纯钛人工牙种植体的研究与应用

CDIC人工牙种植体用纯钛金属材料加工制造而成，经严格的理化性能实验和生物实验性检测，各项指标符合国际相关标准。临床试用8年时间，提出了CDIC种植体的临床分类，建立了严格规范的手术操作程序和配套的种植义齿修复技术，为2714位病员植入了4116枚纯钛种植体。临床资料表明，CDIC种植体年使用量逐年增加，种植义具修复后使用效果良好。96年一季度的资料显示，种植体类型及品种增加，半埋置式锥状螺旋和柱状螺旋种植体各占12%和48%。分期组合式柱状螺旋种植体占25.4%，叶状种植体占4.4%，并对种植体植入手术方式和义齿修复方式进行了讨论与比较。结论说明建立CDIC人工牙种植体系列适合我国人体牙列缺损和缺失后不同颌骨解剖生理学的要求，可在临床推广应用。     

口腔种植体植入放疗骨组织骨整合作用的研究

放疗可降低骨组织再生能力,口腔种植体植入放疗后骨组织中,其成功率低于植入正常骨组织。影响其成功率的主要因素有放疗的剂量、时间、放疗与种植术的间隔时间、高压氧的应用与否及种植体自身的情况等。本文就口腔种植体植入放疗骨组织的临床应用和实验研究作一综述。     

紫外线照射对两种钛种植体表面形貌体外炎症反应的影响

目的:紫外线照射的抛光试件和TiO2纳米管试件对巨噬细胞增殖和细胞因子分泌的影响.方法:抛光组和纳米管组试件避光保存后,各取一半经紫外线照射获得抛光+紫外线组和纳米管+紫外线组试件.测量各组试件表面接触角;在各组试件上培养RAW264.7巨噬细胞,另设空白对照组.检测培养4、24和72h时巨噬细胞黏附和增殖情况;液相芯...     

Effects of Simvastatin on bone healing around titanium implants in osteoporotic rats

Objectives: Osteoporosis is known to impair the process of implant osseointegration. The recent discovery that statins (HMG‐CoA reductase inhibitors) act as bone anabolic agents suggests that statins can be used as potential agents in the treatment of osteoporosis. Therefore, we hypothesized that statins will promote osteogenesis around titanium implants in subjects with osteoporosis. Material and methods: Fifty‐four female Sprague Dawley rats, aged 3 months old, were randomly divided into three groups: Sham‐operated group (SHAM; n=18), ovariectomized group (OVX; n=18), and ovariectomized with Simvastatin treatment group (OVX+SIM; n=18). Fifty‐six days after being ovariectomized (OVX), screw‐shaped titanium implants were inserted into the tibiae. Simvastatin was administered orally at 5 mg/kg each day after the placement of the implant in the OVX+SIM group. The animals were sacrificed at either 28 or 84 days after implantation and the undecalcified tissue sections were obtained. Bone‐to‐implant contact (BIC) and bone area (BA) within the limits of implant threads were measured around the cortical (zone A) and cancellous (zone B) bone regions. Furthermore, bone density (BD) of zone B in a 500 μm wide zone lateral to the implants was also measured. Results: There were no significant differences in BIC and BA measurements in zone A in any of the three groups at either 28 or 84 days after implantation (P>0.05). By contrast, in zone B, significant differences in the measurement of BIC, BA, and BD were observed at 28 and 84 days between all three groups. Bone healing decreased with lower BIC, BA, and BD around implant in OVX group compared with other two groups, and Simvastatin reversed the negative effect of OVX on bone healing around implants with the improvement of BIC, BA, and BD in zone B. Conclusion: Osteoporosis can significantly influence bone healing in the cancellous bone around titanium implants and Simvastatin was shown to significantly improve the osseointegration of pure titanium implants in osteoporotic rats.     

A volumetric study of guided bone regeneration around titanium implants in the New Zealand white rabbit

Previous studies have shown the ability for bone to grow under occlusive membranes. This study was undertaken to determine the time required for bone to form in the space created under the membrane and to determine the amount of bone that may be grown under the membrane. Thirty-two New Zealand white rabbits were divided into three groups. A Brånemark implant, having a diameter of 3.75 mm with a length of 7 mm, was placed in each tibia and Gore-Tex membrane was draped over the implant on the experimental side and tethered to the wound margin. Sixteen rabbits were sacrificed at six weeks, eight at twelve weeks, and eight at eighteen weeks. At six weeks the available space under the membrane was filled to 68 per cent, at twelve weeks it was 45 per cent, and at eighteen weeks 54 per cent. A comparison of bone height measurements on test and control sides showed a significant difference (p=0.0001) at the three time intervals. A comparison of grown bone volumes (test vs control) was also statistically significant (p=0.0001). The ability to grow bone under an occlusive membrane was confirmed but the long-term survival rate and ability to support load needs to be investigated.     

雌激素对骨质疏松时种植体骨愈合的影响:Ⅱ骨计量学和电镜观察

目的 :研究雌激素替代治疗对骨质疏松时种植体骨愈合的影响。方法 :选用32周龄雌性SD大鼠36只 ,并随机分为假手术组、卵巢切除组及雌激素组。卵巢切除12周后于大鼠胫骨近中干骺端植入纯钛螺纹状种植体 ,雌激素组同时肌注苯甲酸雌二醇。种植术后4周及12周分两批处死大鼠 ,摘取胫骨 ;标本分别进行扫描电镜观察和骨计量学测量。结果 :在种植后4周及12周时 ,雌激素组除12周时皮质骨结合率与卵巢切除组无显著差异外 ,其它各项骨计量学参数均显著高于卵巢切除组 (P<0.05或P<0.01) ;而与假手术组比较 ,除骨矿化速度及4周时单位骨量外 ,其他各项指标均无显著差异 (P>0.05)。电镜观察种植体—骨界面愈合雌激素组和假手术组均优于卵巢切除组。结论 :雌激素替代治疗可促进实验性骨质疏松大鼠种植体骨愈合 ;该方法有助于增加临床绝经性骨质疏松患者牙种植体骨整合率     

Radiographic assessment of bone density around integrated titanium implants after ovariectomy in rats

OBJECTIVES: This study evaluated the influence of ovariectomy 8 weeks after implant placement on bone integrated to titanium implants. MATERIAL AND METHODS: Thirty-eight female rats were submitted to a titanium implant at the tibiae proximal methaphysis. After a healing period of 8 weeks the animals were randomly divided into three groups: control (CTL-10 animals), sham-operated (SHAM-14 animals) and ovariectomy (OVX-14 animals). The CTL group was then sacrificed in order to confirm integration of the implant. The SHAM group was submitted to fictitious surgery and the OVX group was submitted to bilateral ovariectomy. After 12 weeks post-implant placement, the SHAM and OVX groups were sacrificed. In order to confirm the systemic osteopenia in rats, a dual-energy X-ray absorptiometry (DXA) was performed. For the evaluation of bone density, digital radiographs were taken. The grey level of the bone adjacent to implant was measured using image software and the bone density was calculated at six points on both sides of the implant. RESULTS: Densitometry measurements of the femur confirmed systemic bone mass loss in the OVX group. Individualized bone analyses of different regions surrounding the implant showed a significantly lower radiographic bone density (P < 0.05) in the cancellous region of the OVX group (77.48 +/- 23.39 grey levels) when compared with the CTL and SHAM groups (91.61 +/- 32.10 and 102.57 +/- 32.50 grey levels, respectively). CONCLUSIONS: The present study showed a decrease of the radiographic bone density in the cancellous region of bone around titanium implants placed 8 weeks before ovariectomy in rats.     

The combined effects of undersized drilling and implant macrogeometry on bone healing around dental implants: an experimental study

This study investigated the effect of undersized preparations with two different implant macrogeometries. There were four experimental groups: group 1, conical implant with an undersized osteotomy of 3.2 mm; group 2, conical implant with an undersized osteotomy of 3.5 mm; group 3, cylindrical implant with an undersized osteotomy of 3.2 mm; group 4, cylindrical implant with an undersized osteotomy of 3.5 mm. Implants were placed in one side of the sheep mandible (n = 6). After 3 weeks, the same procedure was conducted on the other side; 3 weeks later, euthanasia was performed. All implants were 4 mm × 10 mm. Insertion torque was recorded for all implants during implantation. Retrieved samples were subjected to histological sectioning and histomorphometry. Implants of groups 1 and 2 presented significantly higher insertion torque than those of groups 3 and 4 (P < 0.001). No differences in bone-to-implant contact or bone area fraction occupied were observed between the groups at 3 weeks (P > 0.24, and P > 0.25, respectively), whereas significant differences were observed at 6 weeks between groups 1 and 2, and between groups 3 and 4 (P < 0.01). Undersized drilling affected the biological establishment of bone formation around both dental implant macrogeometries.     

Influence of homeopathic treatment with comfrey on bone density around titanium implants: a digital subtraction radiography study in rats

Objective: The objective of this study was to evaluate the influence of homeopathic treatment with comfrey (Shymphytum officinalis 6CH) on radiographic bone density and area around titanium implants. Material and methods: Forty‐eight rats were divided into two groups of 24 animals each: a control group (C) and a test group (SO). Each animal received one titanium micro‐implant placed in the tibia. The animals in Group SO were subjected to 10 drops of comfrey 6CH per day mixed into their drinking water until the day of sacrifice. Eight animals of each group were sacrificed at 7, 14 and 28 days post‐surgery, respectively. Standardized digital radiographs were obtained on the day of implant installation (baseline images) and on the day of sacrifice (final images). Digital subtraction of the two corresponding images was performed to evaluate changes in bone density and the area related to change around the implant between baseline and final images. Results: Subtraction images demonstrated that a significant difference existed in mean shade of gray at 14 days post‐surgery between Group SO (mean 175.3±14.4) and Group C (mean 146.2±5.2). Regarding the area in pixels corresponding to the bone gain in Group SO, the differences observed between the sacrifice periods and groups were only significant at 7 days sacrifice between Group SO (mean 171.2±21.9) and Group C (mean 64.5±60.4). Conclusion: Within the limits of this study, comfrey administration promotes an increase in radiographic bone density around titanium implants in the initial period of bone healing.     

Effect of membranes and porous hydroxyapatite on healing in bone defects around titanium dental implants. An experimental study in monkeys.

The purpose of the present study was to examine the effect of treating bony craters around titanium dental implants with polytetrafluoroethylene membranes PTFE, with and without grafting of hydroxyapatite (HA), and with HA alone. 4 standardized bone defects were prepared in the alveolar ridge of edentulous areas in each of 7 monkeys. A titanium implant was then placed centrally in each defect, and in each monkey, the defects were treated with 1 of the following 4 treament modalities: 1 coverage with PTFE membrane;(2) grafting of HA and covering with a PTFE membrane;(3) HA grafting;(4) no treatment. Following a healing period of 12 weeks, all animals were sacrificed and mesiodistal ground sections of the treated areas were prepared. The histological analysis showed that all bone defects around the implants treated with PTFE membranes and 5 of the defects treated with HA and PTFE membranes were completely filled with new bone. The defects treated with HA alone and the control defects with no treatment only demonstrated new bone formation in the bottom of the defects. The results suggest that bone defects around titanium implants can be 1 treated successfully with PTFE membranes.     

Bone apposition around two different sandblasted and acid-etched titanium implant surfaces: a histomorphometric study in canine mandibles

PURPOSE: The aim of this study was to evaluate bone apposition to a modified sandblasted and acid-etched (SLA) implant surface (modSLA) in the canine mandible as compared with the standard SLA surface. MATERIAL AND METHODS: In this experimental study, all mandibular premolars and first molars were extracted bilaterally in five foxhounds. After a healing period of 6 months, each side of the mandible received six randomly assigned dental implants alternating between the standard SLA and modSLA surface. The dogs were sacrificed at 2 weeks (n=2) or 4 weeks (n=3) after implant placement. Histologic and histomorphometric analyses were then performed for each implant. RESULTS: The microscopic healing patterns at weeks 2 and 4 for the two implant types with the standard SLA and modSLA surfaces showed similar qualitative findings. New bone tissue had already established direct contact with implant surfaces after 2 weeks of healing. The mean percentage of newly formed bone in contact with the implant (BIC) was significantly greater for modSLA (28.2+/-7.9%) than for SLA (22.2+/-7.3%) (P<0.05). This difference was no longer evident after 4 weeks. An increase in BIC for both implant surface types occurred from weeks 2 to 4. This increase was statistically significant when compared with SLA at 2 weeks (P<0.05), but not when compared with modSLA at 2 weeks. CONCLUSION: The data from the present study demonstrate significantly more bone apposition for the modSLA surface than the standard SLA surface after 2 weeks of healing. This increased bone apposition may allow a further reduction of the healing period following implant placement for patients undergoing early loading procedures.