种植体稳定系数测定与种植体负重时机选择

目的:通过测量ITI和Osstem-SS种植系统的稳定系数(ISQ),评价这两种种植体的骨结合情况,为临床确定其上部结构修复时机提供依据。方法:93例牙列缺损患者共植入179颗种植体,根据患者种植区骨量情况分为两组,其中A组为种植区骨量良好,不需骨增量手术病例(62例);B组为种植区骨量不足,需进行骨增量手术病例(31例)。A组共植入125颗种植体,其中ITI种植系统64颗,OSSTEM-SS种植系统61颗;B组共植入54颗种植体,其中ITI种植系统28颗,OSSTEM-SS种植系统26颗。术后即刻及第4、6、8、12、16、24周分别测量各时期种植体稳定系数(ISQ),并同期进行临床和影像学检查。结果:A组中ITI种植系统术后8周ISQ值平均(74.17±1.85),进行负重;OSSTEM-SS种植系统术后12周ISQ值平均(72.00±2.59),进行负重。B组中ITI种植系统术后16周ISQ值平均(65.09±3.42),进行负重;OSSTEM-SS种植系统术后24周ISQ值平均(62.09±6.16),进行负重。负重后临床随访3-24个月所有病例均成功,咀嚼功能良好,患者满意。结论:种植体稳定系数(ISQ)能反应种植体骨结合情况,可以协助医生选择种植后合适的冠修复时机。     

老年糖尿病患者牙周重度破坏后种植研究

目的:研究2型糖尿病老年患者牙周重度破坏后不同血糖水平对于牙齿种植术后炎症指标、种植体稳定性及菌斑指数的影响,探讨患者血糖控制情况和种植牙术后效果的关系。方法:选取我院2011年1月至2013年1月40例在牙周重度破坏后行种植体置入的2型糖尿病老年患者,按照术后8周糖化血红蛋白水平是否≥7.5%分为实验组和对照组,分别测定两组患者术后24小时血常规,对比其白细胞、中性粒细胞及淋巴细胞水平;同时于术后第4、8、12周检测其种植体稳定参数(ISQ);术后3个月、6个月检测其菌斑指数(PLI)。结果:术后24小时,实验组的白细胞、中性粒细胞及淋巴细胞水平显著高于对照组,P0.01;术后第4、8、12周的ISQ值,实验组显著低于对照组,P0.01;术后3个月、6个月的菌斑指数,实验组显著高于对照组,P0.01。结论:2型糖尿病老年患者牙周重度破坏后不同血糖水平与其炎症反应、种植体稳定性及细菌繁殖情况密切相关,控制术前及术后血糖,有利于提高种植体稳定性并降低术后炎症反应,减少细菌繁殖,促进尽早愈合。     

自体颏部骨移植并种植体修复前牙槽骨缺损的应用研究

目的:评价自体颏部骨移植方法在前牙槽骨缺损植骨及种植的效果。方法:对16例前牙骨缺损的患者进行自体颏部骨移植,分别于植骨12～16周后植入种植体,共植入18枚种植体,术后16～20周完成修复治疗。结果:16例自体骨移植患者中,1例出现术后感染,经局部冲洗换药后后愈合良好,其余患者移植骨均已成活,修复后种植体至今均无脱落,局部外形良好。结论:自体颏部骨移植能有效恢复局部牙槽外形,为前牙美学修复提供良好的基础。     

骨诱导无机材料BAM 修复牙种植体周围骨缺损的实验研究

目的:评价骨诱导磷酸钙生物陶瓷(BAMOICPC)与可吸收胶原膜(BME-10X医用胶原膜)在牙种植体周围骨缺损中的修复能力。方法:在兔股骨上植入羟基磷灰石涂层BLB种植体,然后在其侧壁制造高4 mm、宽3 mm、深2 mm的骨缺损。对照组为单纯侧壁骨缺损,实验A组骨缺损区仅覆盖BME-10X膜,B组骨缺损区植入BAMOICPC,C组骨缺损区植入BAMOICPC并加盖BME-10X膜。于术后6个月取带种植体的骨段,通过HE染色和扫描电镜(SEM)分析。结果:对照组骨缺损区种植体表面见纤维包裹,实验A组骨缺损边界区少许骨质移行覆盖,实验B组下半部分缺损区新生骨覆盖。C组新生骨完全覆盖骨缺损区,且较B组硬度高,扫描电镜见与种植体结合更紧密。组织学观察B、C两实验组新生骨均可见比较成熟的哈弗氏管系统。结论:骨诱导磷酸钙生物陶瓷BAMOICPC是一种较理想的骨替代材料,联合运用胶原膜修复种植体周骨缺损效果佳。     

龈下菌斑对种植体周围边缘骨吸收有影响

为探讨龈下菌斑对种植体周围边缘骨吸收的影响,本研究选取2015年2月至2017年10月在我院治疗的80例后牙缺失患者,根据种植后3个月改良菌斑指数(modified plaque index, m PLI)分为A组54例(m PLI为0分)和B组26例(mPLI为1~3分),观察两组种植体周围骨吸收及龈沟出血指数(sulcular bleeding index,SBI),同时检测龈下菌斑微生物。结果表明:A组种植后SBI为(1.06±0.11)分,明显低于B组的(1.20±0.16)分(p0.05);A组近中和远中边缘骨吸收量分别为(1.20±0.16) mm和(1.23±0.18) mm,明显低于B组的(1.40±0.15) mm和(1.37±0.16) mm (p0.05);种植前,A组中间普氏菌、牙龈卟啉单胞菌、福赛拟杆菌和齿垢密螺旋体比例分别为33.33%、18.52%、14.81%和22.22%,明显低于B组的65.38%、61.54%、73.08%和84.62%(p0.05),而直肠弯曲菌和伴放线放线杆菌比例比较差异无统计学意义(p0.05)。本研究初步结论表明龈下菌斑对种植体周围边缘骨吸收有影响,与菌斑微生物可能有一定关系,故在种植体修复时,应注意牙周基础治疗。     

OSFE植骨与不植骨种植修复的临床效果对比研究

目的:比较上颌窦挤压内提升(OSFE)植骨与不植骨种植修复的临床效果。方法:选择上颌后牙区种植修复的35例患者,其剩余牙槽嵴高度(RBH)为4~8 mm,共植入43颗种植体。A组16例患者为植骨组,20个种植位点,牙槽骨可用骨高度平均(5.87±1.19)mm,植入人工骨粉后植入种植体;B组19例患者为不植骨组,23个种植位点,缺牙区牙槽骨可用骨高度平均(5.67±1.10)mm,上颌窦提升后直接植入种植体。6个月后行二期手术完成修复。采用临床检查、X线检查及视觉模拟评分法(visual analogue scale,VAS)进行效果评价。结果:两组病例的牙槽嵴高度差异比较无统计学意义。在平均约36.7个月的随访期内,A组种植体的存留率为100%(20/20),B组中有1枚种植体因咬合力过大及口腔卫生较差脱落,种植体的存留率为95.6%(22/23),两组病例的存留率比较无统计学差异。两组患者的VAS值比较亦相当。所有种植体骨结合良好,种植体周围软组织无炎症,种植义齿咀嚼功能良好。结论:在严格控制适应症、准确掌握种植技巧的前提下,RBH在4~8 mm之间的病例无需额外植入骨代替材料即可取得理想的修复效果,简化了手术的操作,减少了手术的风险和创伤,节省了手术的时间和费用,易被患者接受。     

多孔钛合金不同孔径大小对新骨长入的影响

目的:评价不同孔径多孔钛合金植入物在骨缺损区对新骨长入的影响。方法:采用电子束熔融(EBM)技术制备三种不同孔径(孔径分别为1.0 mm,2.0 mm,3.0 mm)的多孔钛合金材料,其孔隙率依次为73%,79%,86%。将18只家犬随机分为1.0 mm孔径材料组,2.0 mm孔径材料组,3.0 mm孔径材料组,每组6只。制备家犬双侧股骨外侧髁缺损模型,然后植入各孔径组材料,于术后4周,8周,12周分别行大体标本观察,X线片观察,组织形态学观察三组不同孔径材料与周围骨的整合情况及孔隙中的新骨长入情况。结果:通过大体标本观察和X线片观察显示,12周后三组材料均与周围紧密骨连接。其中1.0 mm孔径组材料中心明显成骨,2.0 mm孔径组和3.0 mm孔径组中心仍为较多白色组织填充。组织学观察显示,12周时2.0 mm孔径组和3.0 mm孔径组材料周围有骨质包绕,但中心空洞,基本无骨质形成。1.0 mm孔径组材料周围骨质包绕紧密,孔中新生骨形成较多,且有大量纤维母细胞和软骨细胞形成。各时间点1.0 mm孔径组新生骨面积百分比明显高于2.0 mm孔径组和3.0 mm孔径组,P<0.01,差异具有统计学意义。2.0 mm孔径组和3.0 mm孔径组相比,P>0.05,无显著差异。结论:孔径大小影响多孔钛合金材料的骨长入,适当孔径的设计将更有利于材料的传导成骨。     

XIVE 种植体即刻植入即刻负重的临床观察

目的:评价XIVE种植体在上颌外伤前牙区即刻种植即刻负重修复的临床效果。方法:对26例前牙区单颗或多颗无法保留的外伤残根拔除后,即刻植入XIVE种植体,并即刻负重修复。种植体扭矩控制在35Ncm左右,初期稳定性良好。平均四到五个月后行永久修复。在植入后1、2、4个月对其进行临床及影像学检查。结果:32枚种植体有2枚种植体2周后出现松动,一个月后脱落,其余30枚均在预期时间内形成良好骨性愈合,最终完成修复。结论:上颌前牙区单颗或多颗牙外伤,残根无法保留者,行即刻种植即刻负重修复是可行。早期种植修复有利于减缓牙槽骨的吸收,保留软硬组织的形态,缩短疗程。     

XIVE种植体即刻植入即刻负重的临床观察

目的：评价XIVE种植体在上颌外伤前牙区即刻种植即刻负重修复的临床效果。方法：对26例前牙区单颗或多颗无法保留的外伤残根拔除后,即刻植入XIVE种植体,并即刻负重修复。种植体扭矩控制在35Ncm左右,初期稳定性良好。平均四到五个月后行永久修复。在植入后1、2、4个月对其进行临床及影像学检查。结果：32枚种植体有2枚种植体2周后出现松动,一个月后脱落,其余30枚均在预期时间内形成良好骨性愈合,最终完成修复。结论：上颌前牙区单颗或多颗牙外伤,残根无法保留者,行即刻种植即刻负重修复是可行。早期种植修复有利于减缓牙槽骨的吸收,保留软硬组织的形态,缩短疗程。     

氧化钛纳米管对即刻种植骨结合影响的实验研究

目的:评价氧化钛纳米管对犬即刻种植骨结合效果的影响。方法:犬拔牙后即刻将光滑表面(对照组)和氧化钛纳米管表面(实验组)种植体植入拔牙窝内,于12周后处死取材,进行显微CT扫描、组织学染色分析以及生物力学检测。结果:扫描电镜显示经过阳极氧化后,钛表面形成了直径为30-80纳米的纳米管状结构;12周后,显微CT扫描结果提示实验组骨体积分数(BV/TV)、骨小梁数目(Tb.N)、骨小梁厚度(Tb.Th)均显著高于对照组,骨小梁间隙(Tb.Sp)显著低于对照组,差异具有统计学意义(P0.05)。术后12周,实验组与对照组骨结合率分别为49.35±11.76%、31.79±13.07%,最大拔出力分别为105.28±27.87N、79.23±20.46N,实验组均显著高于对照组,差异均具有统计学意义(P0.05)。结论:氧化钛纳米管表面有利于促进即刻种植后骨结合的效果。     

Evaluation of bone remodeling around single dental implants of different lengths: a mechanobiological numerical simulation and validation using clinical data

Algorithmic models have been proposed to explain adaptive behavior of bone to loading; however, these models have not been applied to explain the biomechanics of short dental implants. Purpose of present study was to simulate bone remodeling around single implants of different lengths using mechanoregulatory tissue differentiation model derived from the Stanford theory, using finite elements analysis (FEA) and to validate the theoretical prediction with the clinical findings of crestal bone loss. Loading cycles were applied on 7-, 10-, or 13-mm-long dental implants to simulate daily mastication and bone remodeling was assessed by changes in the strain energy density of bone after a 3, 6, and 12 months of function. Moreover, clinical findings of marginal bone loss in 45 patients rehabilitated with same implant designs used in the simulation (n = 15) were computed to validate the theoretical results. FEA analysis showed that although the bone density values reduced over time in the cortical bone for all groups, bone remodeling was independent of implant length. Clinical data showed a similar pattern of bone resorption compared with the data generated from mathematical analyses, independent of implant length. The results of this study showed that the mechanoregulatory tissue model could be employed in monitoring the morphological changes in bone that is subjected to biomechanical loads. In addition, the implant length did not influence the bone remodeling around single dental implants during the first year of loading.     

The comparison of marginal bone loss around mandibular overdenture‐supporting implants with two different attachment types in a loading period of 36 months

doi:10.1111/j.1741‐2358.2009.00334.x
The comparison of marginal bone loss around mandibular overdenture‐supporting implants with two different attachment types in a loading period of 36 months Objective: The aim of this study was to assess the influence of attachment types on the marginal bone loss (MBL) around dental implants supporting mandibular overdentures (OVD). Background: There are a number of in vitro studies evaluating the influence of several factors on MBL around implants. Material and methods: Mandibular OVD patients appearing at routine recall sessions consecutively 6, 12, 24 and 36 months after loading were included in the study group. All patients received mandibular OVD with either ball or bar attachments. Measurements were obtained from images of successive radiographs, which were scanned and digitised before, and analysed at ×20 magnification. Statistical analyses were utilised in this study to assess the mean marginal bone level changes as well as to explore the potential effect of several parameters such as the cantilever or the attachment type on bone loss. Results: One hundred and twenty‐six implants in 51 patients with a mean age of 59.39 ± 9.99 years were evaluated. There was no statistical significant difference between the distal and mesial bone loss rates of single or splinted attachment types, whereas bone loss rates were statistically higher in cantilever situations. Conclusion: Within the limitations of this study, gender, age and diameter of the implants do not play a role in MBL. Length of the implant is an important factor in marginal bone level maintenance. The attachment type for OVD support seems not to influence MBL, but cantilevering of the bars increases bone loss significantly.     

Effect of guided bone regeneration on bone quality surrounding dental implants

Bone quality as well as its quantity at the implant interface is responsible for determining stability of the implant system. The objective of this study is to examine the nanoindentation based elastic modulus (E) at different bone regions adjacent to titanium dental implants with guided bone regeneration (GBR) treated with DBM and BMP-2 during different post-implantation periods. Six adult male beagle dogs were used to create circumferential defects with buccal bone removal at each implantation site of mandibles. The implant systems were randomly assigned to only GBR (control), GBR with demineralized bone matrix (DBM), and GBR with DBM + recombinant human bone morphogenetic protein-2 (rhBMP-2) (BMP) groups. Three animals were sacrificed at each 4 and 8 weeks of post-implantation healing periods. Following buccolingual dissection, the E values were assessed at the defects (Defect), interfacial bone tissue adjacent to the implant (Interface), and pre-existing bone tissue away from the implant (Pre-existing). The E values of BMP group had significantly higher than control and DBM groups for interface and defect regions at 4 weeks of post-implantation period and for the defect region at 8 weeks (p < 0.043). DBM group had higher E values than control group only for the defect region at 4 weeks (p < 0.001). The current results indicate that treatment of rhBMP-2 with GBR accelerates bone tissue mineralization for longer healing period because the GBR likely facilitates a microenvironment to provide more metabolites with open space of the defect region surrounding the implant.     

Reconstruction of the edentulous mandible with fresh frozen bone grafts and implants: a 4-year report of a prospective clinical study

Allogen bones from tissue bank are often used in dentistry although the data analyzing the long-term success in mandible are scarce. This study evaluated by computed tomography scans (CTS) the bone resorption around the implants installed on fresh frozen bone (FFB) previously grafted, after 4 years of occlusal rehabilitation. Six subjects were grafted with blocks in posterior mandible using FFB. After 6 months, 27 implants were placed and after further 4 months the prostheses were delivered. Following 4 years of the final rehabilitation procedures, another CTS was done in order to measure the resorption in periimplant bone crest at the proximal implant surfaces. It was observed a 100 % survival rate of the implants after 4 years of the fixture installation. The marginal bone resorption after 48 months was 2.82 ± 1.63 mm and no statistical significant difference was observed along the region where the implants were fixed when compared with the interimplantar space. In addition there was no significant correlation regarding the length of the implant used and the amount of marginal bone resorption. The conclusion is that grafted areas with FFB are suitable to implant installation in the posterior mandible.     

Prognosis of implant longevity in terms of annual bone loss: a methodological finite element study

Dental implant failure is mainly the consequence of bone loss at peri-implant area. It usually begins in crestal bone. Due to this gradual loss, implants cannot withstand functional force without bone overload, which promotes complementary loss. As a result, implant lifetime is significantly decreased. To estimate implant success prognosis, taking into account 0.2 mm annual bone loss for successful implantation, ultimate occlusal forces for the range of commercial cylindrical implants were determined and changes of the force value for each implant due to gradual bone loss were studied. For this purpose, finite element method was applied and von Mises stresses in implant–bone interface under 118.2 N functional occlusal load were calculated. Geometrical models of mandible segment, which corresponded to Type II bone (Lekholm & Zarb classification), were generated from computed tomography images. The models were analyzed both for completely and partially osseointegrated implants (bone loss simulation). The ultimate value of occlusal load, which generated 100 MPa von Mises stresses in the critical point of adjacent bone, was calculated for each implant. To estimate longevity of implants, ultimate occlusal loads were correlated with an experimentally measured 275 N occlusal load (Mericske-Stern & Zarb). These findings generally provide prediction of dental implants success.     

Effect of electromagnetic field on bone regeneration around dental implants after immediate placement in the dog mandible: a pilot study

doi: 10.1111/j.1741‐2358.2011.00525.x Effect of electromagnetic field on bone regeneration around dental implants after immediate placement in the dog mandible: a pilot study Background: Accelerating bone healing around dental implants can reduce the long‐term period between the insertion of implants and functional rehabilitation. Objective: This in vivo study evaluated the effect of a constant electromagnetic field (CEF) on bone healing around dental implants in dogs. Materials and methods: Eight dental implants were placed immediately after extraction of the first pre‐molar and molar teeth on the mandible of two male dogs and divided into experimental (CEF) and control groups. A CEF at magnetic intensity of 0.8 mT with a pulse width of 25 μs and frequency of 1.5 MHz was applied on the implants for 20 min per day for 2 weeks. Result and conclusion: After qualitative histological analysis, a small quantity of newly formed bone was observed in the gap between the implant surface and alveolar bone in both groups.     

Numerical investigation of bone remodelling around immediately loaded dental implants using sika deer (Cervus nippon) antlers as implant bed

This study combines finite element method and animal studies, aiming to investigate tissue remodelling processes around dental implants inserted into sika deer antler and to develop an alternative animal consuming model for studying bone remodelling around implants. Implants were inserted in the antlers and loaded immediately via a self-developed loading device. After 3, 4, 5 and 6 weeks, implants and surrounding tissue were taken out. Specimens were scanned by μCT scanner and finite element models were generated. Immediate loading and osseointegration conditions were simulated at the implant-tissue interface. A vertical force of 10 N was applied on the implant. During the healing time, density and Young’s modulus of antler tissue around the implant increased significantly. For each time point, the values of displacement, stresses and strains in the osseointegration model were lower than those of the immediate loading model. As the healing time increased, the displacement of implants was reduced. The 3-week immediate loading model (9878 ± 1965 μstrain) illustrated the highest strains in the antler tissue. Antler tissue showed similar biomechanical properties as human bone in investigating the bone remodelling around implants, therefore the use of sika deer antler model is a promising alternative in implant biomechanical studies.     

Breast MRI in nonpalpable breast lesions: a randomized trial with diagnostic and therapeutic outcome – MONET – study

Background

In orthodontic treatment, anchorage control is a fundamental aspect. Usually conventional mechanism for orthodontic anchorage control can be either extraoral or intraoral that is headgear or intermaxillary elastics. Their use are combined with various side effects such as tipping of occlusal plane or undesirable movements of teeth. Especially in cases, where key-teeth are missing, conventional anchorage defined as tooth-borne anchorage will meet limitations. Therefore, the use of endosseous implants for anchorage purposes are increasingly used to achieve positional stability and maximum anchorage.

Methods/Design

The intended study is designed as a prospective, multicenter randomized controlled trial (RCT), comparing and contrasting the effect of early loading of palatal implant therapy versus implant loading after 12 weeks post implantation using the new ortho-implant type II anchor system device (Orthosystem Straumann, Basel, Switzerland). 124 participants, mainly adult males or females, whose diagnoses require temporary stationary implant-based anchorage treatment will be randomized 1:1 to one of two treatment groups: group 1 will receive a loading of implant standard therapy after a healing period of 12 week (gold standard), whereas group 2 will receive an early loading of orthodontic implants within 1 week after implant insertion. Participants will be at least followed for 12 months after implant placement. The primary endpoint is to investigate the behavior of early loaded palatal implants in order to find out if shorter healing periods might be justified to accelerate active orthodontic treatment. Secondary outcomes will focus e.g. on achievement of orthodontic treatment goals and quantity of direct implant-bone interface of removed bone specimens. As tertiary objective, a histologic and microtomography evaluation of all retrieved implants will be performed to obtain data on the performance of the SLA surface in human bone evaluation of all retrieved implants. Additionally, resonance frequency analysis (RFA, Osstell? mentor) will be used at different times for clinically monitoring the implant stability and for histological comparison in order to measure the reliability of the resonance frequency measuring device.

Trial registration

Current Controlled Trials ISRCTN97142521.