愈合时间对微型种植体支抗稳定性的影响

目的：研究在相同力值牵引下,愈合时间对微型种植体支抗稳定性的影响。方法：在8只Beagle犬上颌根间牙槽骨中植入49颗微型种植体支抗,分别在即刻负载、愈合2周、愈合4周、愈合12周后施以150g水平牵引力,定期注射荧光标志物,负载2个月后处死动物。制作种植体-骨的不脱钙硬组织切片．进行荧光显微镜观察、组织形态学测量和推出试验。采用SAS6．12软件包中的单因素方差分析和SNK法分析各组间差异,相关性分析BIC、BSA值与生物力学性能参数的相关性。结果：4组标本的骨结合百分率（bone—to—implant contaet,BIC）和骨充填率（bone stlrface area,BSA）分别为（46．6±2．72）％、（44．08±3．62）％、（17．07±0．63）％、（32．85±3．01）％及（66．39±2．94）％、（64．96±5．11）％、（36．82±0．08）％、（70．33±4．07）％。愈合4周与其他3组之间均有显著性差异。4组标本种植体-骨界面的最大剪切力分别是（270．4±20．36）N、（270．4±6．97）N、（105.8±3．73）N、（335．07±17．22）N。愈合12周组与其他3组之间均有显著性差异。种植体-骨界面的总吸收能量情况与最大剪切力相似。微型种植体的生物力学性能与BSA的相关系数显著高于其与BIC的相关系数（心0．051。结论：愈合12周是一个较为理想的负载前愈合时间。即刻负载和愈合2周负载也可以接受,但必须注意种植体的即刻固位和即刻稳定性。而愈合4周负载则不利于种植体的稳定。     

种植体骨结合与拔牙创愈合时间的相关性实验研究

目的：研究拔牙后创口愈合时间对种植体骨结合的影响,探讨拔牙后最佳种植体植入时间。方法：在拔除家犬的下颌双侧第二三前磨牙后不同时间植入种植体,3个月后处死动物观察种植体与拔牙窝之间新骨生成情况及密度并测量骨接触率。结果：0周组与3周组、6周组、9周组比较,差异有统计学意义（P〈0.05）,0周组的骨接触率明显低于3周组、6周组和9周组。3周组与9周组、6周组与9周组之间亦有非常显著性差异（P〈0.05）。6周组的骨接触率略高于3周组,但统计学分析无显著性差异（P〉0.05）。结论：在种植手术3个月时,即刻种植的骨接触率最低,拔牙3周、6周时种植的骨接触率无明显差异,拔牙后3周种植即能在短期内达理想骨结合。     

微型种植钉的长度直径对生物力学的影响

目的对比评价临床常用的3种类型(不同长度、直径)微型种植钉的生物力学特点。方法应用种植钉48枚,新西兰大白兔8只。采用拉出试验,扭转强度试验,在即刻与愈合4周后进行生物力学测量。结果长度为6mm,直径为1.9mm的种植钉相对于同等长度,直径为1.5mm的种植钉在“种植后即刻”与“愈合4周”时,最大剪切力均表现出显著性优势。愈合4周后,直径为1.9mm的种植体在最大扭转强度上表现出显著性的优势。结论在骨质量较差的部位选择较大直径的种植体有利于种植体的稳定。     

上颌窦底冲压提升法种植修复122例缺牙的临床观察

目的探讨上颌窦底冲压提升技术在上颌后牙区种植修复中的应用效果和技术特点。方法1998年7月至2004年7月,共完成122例上颌窦底冲压提升种植修复病例。男性48例,女性74例,平均年龄46·5岁(20~69岁),共植入157枚种植体。随访5年以上21例,3年以上41例,2年以上27例,1年以上33例,平均随访29·7个月。观察方法为临床检查和X线检查。患者均因上颌后牙种植区牙槽嵴顶至上颌窦底之间的剩余骨高度在8~11mm,无法植入足够长度的种植体,因而采用上颌窦底冲压法局部提升上颌窦底骨板及黏骨膜,提升幅度为2~5mm。术中未使用任何骨移植材料,同期植入种植体。若种植体植入时的扭力>0·25N·m,则行一段式种植体直接安装愈合基台,3~4个月后进行种植义齿修复;若种植体植入时的扭力<0·25N·m,则采取埋入式种植技术,3~4个月后再行Ⅱ期种植体暴露手术及修复。结果122例中有12例上颌窦黏骨膜穿破,但在观察期内未发生上颌窦炎等并发症。157枚种植体均获得良好的骨结合并已完成种植修复,至2005年10月为止,无种植体脱落,患者对修复效果满意。结论上颌窦底冲压提升种植修复技术安全、简便、易行;手术创伤小,可在上颌后牙区种植修复病例中选用。     

不同愈合时间下挤压植入种植体对Beagle犬骨界面改建的组织形态学测定

目的：研究不同愈合时间下挤压植入微种植体对其周围骨界面改建的影响。方法：采用自身对照原则,将36枚微种植体植入6只成年Beagle犬上颌后牙区。左右各植入3枚种植体,一侧为实验组以骨挤压植入,对侧为对照组。每侧随机分配植入不同愈合时间（2周,4周和8周）的种植体,取带有种植体骨标本制备不脱钙的超硬组织切片,采用组织形态学定量测定的方法,对钛种植体骨界面改建过程进行动态观察,从定量的角度分析其变化的差异。结果：实验组与对照组种植体骨接触率均随愈合时间的延长而增加。实验组愈合2周,4周时种植体骨接触率明显高于对照组,8周时趋于一致。实验2周组与8周组种植体骨接触率表现出显著性差异,对照2周组与4周组存在显著性差异。结论：愈合早期骨挤压可以提高种植体骨整合率,提示需要早期加载的微种植体以骨挤压术式植入可提高种植体稳定一I生。     

加载时机对硬腭骨膜下种植体愈合结果的影响

目的研究硬腭骨膜下种植体加载时机对其愈合结果的影响。方法6只杂种猪分为3组,每组2只,每只植入4枚硬腭骨膜下种植体。分别于植入后4周、8周、12周时给予种植体9．8N的骀向持续载荷。加载4周后处死动物。测量从骨面去除每个种植体的拉出力,对标本进行组织学检查,拉出的种植体表面进行扫描电镜观察和能谱分析。结果21个植体成功愈合,3组种植体拉出力以中位数（四分位数间距）表示,依次为41．550（4．75）N,50．800（14．675）N和52．800（17．65）N（P〉0．05）。各组样本均存在三种愈合形式：炎性纤维愈合、纤维愈合和骨性愈合。炎性纤维愈合植体拉出力最小,而骨性愈合植体拉出力最大。结论对于愈合期在1个月以上的硬腭骨膜下种植体,加载时机不会显著影响其愈合结果;愈合类型对硬腭骨膜下种植体的结合强度起关键作用。     

不同植入扭矩对种植体骨结合影响的临床初步探究

目的利用共振频率分析法观察不同的种植体植入扭矩值对不同时间点种植体稳定性以及骨结合效果的影响。方法根据纳入及排除标准选择牙列缺损成年患者49名,共植入86颗种植体,手术由同一高年资种植科医生操作完成。根据种植体植入就位后的所测最终扭矩值(Itv)进行分组:A低扭矩组,Itv为0~15 N·cm;B中扭矩组,Itv为16~35 N·cm;C高扭矩组,Itv为36~50 N·cm。利用共振频率分析仪分别对种植即刻、术后8周、术后12周的稳定指数(ISQ)进行测量分析,比较组内以及不同组间不同时间点种植体稳定性以及骨结合效果的差异。结果 1各扭矩组内比较,随着时间的延长,所有组ISQ均呈上升趋势,其中低、中扭矩组内各时间点间均有统计学差异,高扭矩组内各时间点间均无统计学差异。2各扭矩组间第8周ISQ值无明显差异,低扭矩组第8周ISQ值增加幅度最大;各扭矩组间第12周ISQ值无明显差异。结论种植体植入8周以内是形成良好的种植体骨结合的关键时期;不同的种植体植入扭矩值对于8周以后的骨结合效果影响差异不显著。     

腭部种植体支抗稳定性的临床研究

目的评价腭部种植体支抗系统在临床固定矫治技术正畸治疗中的稳定性。方法将直径5.0mm、长6mm的种植体植入19例错畸形患者上颌前磨牙区腭中缝的硬腭,愈合期4周,以横腭杆连接上颌双侧磨牙和种植体作为强支抗,配合MBT矫治技术常规减数正畸治疗。对种植体植入时和支抗作用完成种植体取出前的头影测量指标进行配对比较。结果本组腭部种植体支抗成功率为84.3%,16颗种植体在口内行使功能的时间10～36个月,平均为(23.08±8.06)个月。种植体植入到种植体取出,IL-X轴分别为(62.88±5.85)mm和(62.45±6.70)mm,IL-Y轴为(36.66±5.41)mm和(37.96±4.90)mm,IAP-PP为(73.81±8.84)°和(74.72±9.22)°,IAP-Y轴为(62.09±9.33)°和(63.85±10.96)°,U6-Y轴为(20.80±5.87)mm和(21.49±6.00)mm,经配对t检验,差异均无统计学意义。结论腭部种植体支抗种植系统承载临床正畸力能保持稳定,从而起到增强磨牙支抗作用。     

甲状旁腺激素(1-34)联合珊瑚转化型羟基磷灰石促进种植体周围骨缺损再生修复的实验研究

目的 探究甲状旁腺激素(1-34) [parathyroid hormone(1-34),PTH(1-34)]联合珊瑚转化型羟基磷灰石(coralline hydroxyapatite,CHA)对种植体周围骨缺损处骨再生修复的影响.方法 在8只杂种犬的两侧胫骨各制备两个种植窝,于种植窝的一侧骨壁创造骨缺损.将种植体植入种植窝,CHA植入骨缺损处.术后将8只犬分为实验组和对照组,每组各4只.实验组每周连续3d背部皮下注射40 μg/kg PTH(1-34)溶液,对照组以同样方法注射等量生理盐水.术后4和8周两组各处死2只动物获取标本,进行生物力学测试、X线片和组织学观察.结果 术后4、8周实验组骨缺损处的密度影均高于对照组,种植体与骨接触的界面间未见低密度透射影像;实验组种植体最大拔出力值(199.8、411.5 N)均显著高于同期的对照组(100.1、184.5 N),P＜0.05;拔出力值实验组术后4周与对照组术后8周接近.术后4周实验组骨缺损区新生骨小梁较对照组稍粗,连续性较好;种植体表面与新生骨直接接触.术后8周实验组新生骨较对照组致密;种植体表面与新生骨接触较对照组广泛.结论 PTH(1-34)联合CHA可促进种植体周围骨缺损再生修复,使种植体与骨愈合周期缩短.     

上颌单个前牙早期种植的软组织效果观测

目的:对上颌单个前牙早期种植牙龈软组织效果进行观察和分析。方法:28例上颌单个前牙缺失患者,在缺牙后4～8周,平均(6.2±2.4)周,植入Straumann种植体28枚。其中12例患者同期进行骨移植术。种植体愈合3～7个月后行永久修复。随访时间为5～24个月(平均14个月)。此期间使用改良龈沟出血指数(modification sulcus bleedingindex,MBI)、探诊深度(probing depth,PD)、牙龈乳头指数(papilla fill index,PFI)、PES(pink esthetic score)评分对种植修复体周围软组织进行评价,同时对种植修复体及对侧同名牙牙冠高度进行测量。结果:28枚种植体留存率100%。12例MBI记分为1。PD平均值为(3.1±1.3)mm。PFI得分为"2"以上27例。PES平均得分为10.45±2.25。种植修复体牙冠平均高度为(8.3±2.2)mm(7.0～11.7 mm),与对侧同名牙牙冠高度差值平均(0.8±0.3)mm(-0.7～1.5 mm)。结论:单个前牙早期种植,牙龈软组织的近期效果令人满意。     

不同愈合期施加载荷对正畸微种植体稳定性影响的研究

目的 探讨微种植体在不同愈合时间施加载荷的生物力学性能和稳定性。方法 将64枚微种植体以（12±1） N·cm扭力植入在8只Beagle犬的下颌牙槽骨上,实验组微种植体于植入后即刻及愈合1、3、8周时施加载荷0.98 N,持续10周,对照组不施加载荷,分别于植入后1、3、8、10周取材。测量两组微种植体的最大旋出扭力,以评价微种植体-骨界面结合强度,旋出微种植体用扫描电子显微镜观察微种植体-骨界面的形态。结果 实验组即刻载荷及愈合1、3、8周载荷的微种植体平均最大旋出扭力分别为4.10、4.25、2.42、4.42 N·cm,其中愈合3周的旋出扭力明显低于其他组（P<0.05）;对照组愈合3周的旋出扭力亦明显低于其他组。实验组愈合3周微种植体的表面为编织骨样结构;而其他愈合时间施加载荷后,其表面多为板层骨样结构。结论 微种植体植入后3周左右为稳定性危险期,此时施加载荷不利于微种植体的稳定。临床应选择微种植体的功能愈合期,即植入后即刻,或愈合1、8周后进行适度加载。     

Does rotational strain at screw tightening affect the attainment or maintenance of osseointegration?

OBJECTIVES: This study investigated whether rotational strain affects osseointegration. MATERIAL AND METHODS: A total of 135 male rats were divided into five groups: 2-w rotation, 4-w rotation, 8-w rotation, 12-w rotation and control. Two hundred and seventy implants were inserted in rat tibia. The control group received no strain, while the 2-w, 4-w, 8-w and 12-w rotation groups received rotational strain at 2, 4, 8 and 12 weeks after implant placement, respectively. Removal torque (N cm) was measured in vivo. Bone contact rate (%) was calculated histomorphologically. Immunostaining for osteonectin (ON), osteopontin (OPN) and osteocalcin (OCN) was performed. The removal torque and bone contact rate were analyzed using one-way analyses of variance and the Scheffé method. RESULTS: At 4 weeks, the torque was significantly higher in the 2-w rotation group (1.30+/-0.44 N cm) than in the control group (0.79+/-0.67 N cm). From 8 to 16 weeks, the strained groups showed no significant differences from the control group. From the bone contact rates, bone formation was larger in the 4-week rotation group (62.9+/-10.7%) than in the control group (42.1+/-17.9%) at 8 weeks. The 4-week rotation group showed higher bone contact rate (61.1+/-11.3%) compared with the other strained groups and maintained this higher value until 16 weeks, showing no significant difference from the control group (72+/-5.2%). At the implant-bone interface, OPN was widely distributed and OCN was detected at a low level; however, ON could not be observed in any group. CONCLUSIONS: The bone contact rate changed when rotational strain was exerted at different periods after implant placement. However, the removal torque and distribution of extracellular matrix proteins were not adversely affected by the rotational strain.     

The influence of diabetes mellitus and insulin therapy on biomechanical retention around dental implants: a study in rabbits

The oral rehabilitation by dental implants in patients with diabetes remains a controversial issue. The aim of this study was to evaluate the influence of diabetes mellitus and insulin therapy on the bone healing around dental implants using torque removal. Twenty-seven rabbits were randomly divided into 3 groups with 9 animals each: control (C) group, induced diabetic (D) group, and insulin-treated diabetic (ITD) group (10 U/day). After 1 week, one implant was inserted at the tibial metaphysis of the animals. The glucose levels were periodically evaluated through the glucose-oxidase enzymatic method. The animals were killed at 4, 8, and 12 weeks after surgery and the biomechanical test was performed using a torque manometer. Statistically significant differences regarding the removal torque of the implant could not be found at 4 weeks (P = 0.2) among groups. Group C showed statistically higher values than groups D and ITD at the experimental periods of 8 (P = 0.0001 and P = 0.0002, respectively) and 12 weeks (P = 0.0053 and P = 0.001, respectively). There were no statistical differences between D and ITD groups in any of the experimental periods. Diabetes mellitus has negatively influenced the mechanical retention of implants placed at the tibial metaphysis of rabbits. Therapy with insulin did not induce any changes.     

Early loading (2 or 6 weeks) of sandblasted and acid-etched (SLA) ITI implants in the posterior mandible. A 1-year randomized controlled clinical trial

The aim of this 1-year prospective controlled clinical trial was to evaluate the effect of early loading of ITI solid screw titanium implants with a sandblasted and acid-etched (SLA) surface on clinical and radiographic parameters. MATERIAL AND METHODS: Twenty-seven consecutively admitted patients presenting bilateral edentulous posterior mandibular areas and in need of prosthetic reconstruction were recruited. Sixty-seven ITI standard solid screw implants with an SLA surface, a diameter of 4.1 mm and a length of 8, 10 or 12 mm were installed bilaterally in molar and premolar areas according to a one-stage surgical protocol. One week (test) and 5 weeks (control) after implant placement, solid ITI prosthetic abutments were connected using a torque of 35 N cm. No provisional restoration was fabricated. Two weeks (test) and 6 weeks (control) after implant placement, porcelain-fused-to-metal single-tooth crowns were cemented. Clinical measurements were obtained at day 0 and 2, 6, 12, 24 and 52 weeks thereafter. Periapical radiographs were taken immediately after implant placement, after 6 weeks and at the 1-year examination. RESULTS: After 1 year, implant survival was 100%. Two test and one control implants rotated at the time of abutment connection and were left unloaded for 12 additional weeks. At the 1-year examination, no statistically significant differences were found between the test and control sites with respect to pocket probing depths (2.6 mm +/- 0.5 vs. 2.7 mm +/- 0.5), mean clinical attachment levels (3.1 mm +/- 0.4 vs. 3.2 mm +/- 0.5), mean percentages of sites bleeding on probing (9.7% vs. 8.3%), mean widths of keratinized mucosa (1.8 mm +/- 0.4 vs. 1.9 mm +/- 0.5), mean PerioTest values (-1.4 PTV +/- 0.9 vs. -1.6 PTV +/- 0.8) or mean crestal bone loss measurements (0.57 mm +/- 0.49 vs. 0.72 mm +/- 0.50). CONCLUSION: Based on these results, loading of titanium implants with an SLA surface as early as 2 weeks did not appear to jeopardize the osseointegration healing process in the posterior mandible. Furthermore, implants rotating at 35 N cm, if left unloaded for additional 12 weeks, did not negatively affect clinical and radiographic outcomes.     

Rate of pull-out strength gain of dual-etched titanium implants: a comparative study in rabbits.

The purpose of this study was to investigate the rate of pull-out strength gain of an etched titanium implant surface. Rabbit tibiae were used to compare machined titanium and proprietary dual-etched titanium implants. Two custom cylindric implants (3 mm in diameter and 4 mm in length) were placed in each right anteromedial tibia in 31 rabbits. At weeks 1, 2, 3, 4, 5, and 8, the implants in 5 rabbits were subjected to failure shear loading in a pull-out test. For shear failure testing, each tibial segment was mounted in a precision alignment jig, and an Instron pull-out test was performed on each implant. Beginning at week 3, there was a statistically significant difference (P < .01) between the dual-etched and the machined implants. There was a significant increase in strength for dual-etched implants between week 5 and week 8, while the machined implants did not show an increase during this time interval. The etched implants maintained a significantly greater pull-out strength for the remainder of the study, with a 3.2-fold greater mean strength at 8 weeks, equivalent to 6 months in humans. At 3 weeks, the etched implant's strength exceeded the strength that the machined implant had achieved at 8 weeks. In short-term healing in the rabbit tibia, the dual-etched surface demonstrated a more rapid rate of pull-out strength gain than the machined surface and remained significantly stronger throughout the 8 weeks of the study.     

Ninety percent success in palatal implants loaded 1 week after placement: a clinical evaluation by resonance frequency analysis

To investigate the behaviour of early loaded palatal implants when observed with resonance frequency analysis (RFA). Twenty patients (seven males and 13 females, mean age 26.4 years) received one palatal implant each (length: 4 mm, diameter: 3.3 mm; Orthosystem) for maximum orthodontic anchorage. The implants' stability was observed by RFA. Measurements were carried out at the time of surgery, after first orthodontic loading and subsequently once a week over a period of 12 weeks. Two palatal implants were lost. The other 18 remained stable. The average period from insertion to first loading was 6.7+/-0.8 days. The mean orthodontic force applied was 272.2+/-73.2 cN. The implant stability quotient (ISQ) value at the time of surgery averaged 69.4+/-3.9. The mean ISQ value 6.7 days after insertion was 69.8+/-3.6. Twelve weeks post-surgery the mean ISQ value was 69.8+/-3.5. A statistically significant decrease in stability was observed after 2 and 3 weeks post-surgery (P=0.005 and 0.04). The behaviour of early loaded palatal implants showed an initial decrease of the ISQ values. From 6 weeks post-surgery onward the ISQ values increased. Within the limitations of this study, the results suggest that the healing time of palatal implants reported in the literature (12 weeks) should be discussed. An orthodontic loading of palatal implants 6 weeks post-surgery with a force up to 400 cN seems to be justified. Yet further investigations are necessary to evaluate the behaviour of early loaded palatal implants considering observation periods of over 12 weeks.     

微/纳米表面对骨质疏松下种植体骨结合的影响

[摘要] 目的 评价不同时间微/纳米表面对骨质疏松大鼠种植体骨结合的影响。方法 机械处理组和微/纳米表面组种植体植入去势SD大鼠股骨远端,术后0、4、12周对大鼠进行活体显微CT扫描。术后12周大鼠处死取材,行组织学分析及生物力学检测。结果 显微CT结果提示,实验组骨小梁数目(Tb.N)、骨体积分数(BV/TV)在4周和12周均显著高于对照组(P<0.01),骨小梁间隙(Tb.Sp)在12周显著减小(P<0.01)。术后12周,对照组最大拔出力及骨结合率分别是(76.85±12.05)N,(20.73±2.56)%,而在实验组为(99.25±10.42)N,(28.63±1.82)%,统计学结果显示两组结果实验组均高于对照组(P<0.01)。结论 微/纳米表面有利于改善骨质疏松条件下种植体骨结合。     

低幅高频振动对比格犬种植体周围骨愈合和种植体骨结合的影响

目的:低幅高频(low-magnitude high-frequency,LMHF)振动已被证实在骨愈合中起到重要作用.本研究旨在评估LMHF振动直接加载于纯钛种植体后,对种植体周骨愈合及种植体骨结合的影响.方法 :6 只拔除下颌前磨牙及磨牙的雄性比格犬常规饲养3 个月后,在双侧下颌骨前磨牙及磨牙区分别植入3 颗纯钛种...     

The influence of simultaneous versus delayed placement on the stability of titanium implants in onlay bone grafts. A histologic and biomechanic study in the rabbit.

A rabbit model was used to study the healing and stability of titanium implants in free bone grafts, placed simultaneously or after 8 weeks of healing and followed for 24 weeks. The skull bone was used as donor site and the tibial metaphysis as recipient site. Stability measurements were performed by using resonance frequency analysis (RFA) at implant placement and after 4, 8, 16 and 24 weeks of healing. Statistically significant higher resonance frequencies were measured at all time points for the delayed approach implants. Removal torque tests after 24 weeks revealed no differences between the two procedures. Histologic ground sections were prepared on specimens taken after 8, 16 and 24 weeks of healing. More bone-implant contacts were observed in the bone graft for the implants inserted in a delayed fashion, while there was no statistically significant difference in the degree of total bone-implant contact between the two groups. It is concluded that delayed implant placement in autogenous onlay bone grafts results in a better integration and stability of the implants.