Optimal Palatal Configuration for Miniscrew Applications

Objective:To test the hypothesis that palatal bone is not able to support titanium miniscrews (11 mm in length and 2 mm in diameter) when subjected to forces normally generated during orthodontic treatment.Materials and Methods:The miniscrew–palatal bone system was modeled and analyzed using the commercial finite element method software ANSYS Multiphysics 10.0; tests were done in both a state of total osseointegration and in the absence of it. Calculations were carried out in both cases in configurations where the miniscrew was inserted into two different palatal regions: in the first it was anchored in one layer of cortical bone and in the underlying trabecular bone; in the second, two layers of cortical bone and the trabecular bone in between were involved. Two different loads were taken into account, 240 g_f and 480 g_f, both of which are within the normal range for orthodontic treatment, and applied to the miniscrew heads.Results:The results demonstrated that the miniscrew inserted into the palate can be anchored to bone and loaded within normal orthodontic force range without exceeding the stress levels that lead to bone fracture. The osseointegrated system was characterized by a lower level of stress than the nonosseointegrated one, but anchorage within the second layer of cortical bone markedly reduced the stress on the trabecular bone, thereby improving the stability of the implant, also in the absence of osseointegration.Conclusions:The hypothesis is rejected. Miniscrews loaded within the normal orthodontic force range do not exceed the stress levels that lead to bone fracture.     

Ultrastructure of the Interface between Periodontal Tissues and Titanium Mini-Implants

Objective:To describe the ultrastructure of the interface between periodontal tissues and titanium mini-implants in rat mandibles.Materials and Methods:A titanium mini-implant was placed between the buccal roots of the mandibular first molar of 24 adult rats. After 21, 30, 45, 60, 90, and 120 days of implantation, the mandibular portion was removed and fixed in cacodylate-buffered 2% glutaraldehyde + 2.5% formaldehyde. The material was decalcified and processed for scanning and transmission electron microscopy.Results:Ultrastructural analysis revealed a thin cementum-like layer at longer times after implantation at the areas in which the periodontal ligament was in contact with the implant.Conclusions:The alveolar bone and the periodontal ligament reorganized their constituents around the implant, and a thin cementum-like layer was formed at longer times after implantation at the areas in which the periodontal ligament was in contact with the implant.     

Three-dimensional finite element analysis of implant stability in the atrophic posterior maxilla: a mathematical study of the sinus floor augmentation

Sinus lifting is performed with a variety of materials and techniques without a precise knowledge of the quantity of augmentation. This study based on three-dimensional finite element analysis was designed to show which surgical procedure and which amount of peri-implant packing yields the best bony support for dental implants. Eight 3D-FE models were used. Four modeled standard situations simulated quantitatively different packing situations produced by differences in surgical approach: i. no packing; ii. thin 1 mm bony sheath; iii. oblique subcomplete packing; iv. complete bony peri-implant packing up to the implant end. A fifth model compared a standard implant with a length of 13.5 mm and a diameter of 3.75 mm with a 7-mm-long and 5-mm-thick implant. In three additional models the stress response of the bone-implant system was evaluated in the absence of a cortical layer, thus simulating an extreme degree of maxillary atrophy. In all models the modeled implants were loaded at their points of emergence with an assumed force of 100 N. The vector of the loading force was inclined 30 degrees posteriorly relative to the implant axis and 30 degrees away from the sagittal plane. The bone-implant interface was assumed to be perfect simulating full osseointegration. The final evaluation of the FE models showed complete peri-implant packing to reduce displacements of the implant tip by 32% vs. no sheathing/packing. Van Mises' equivalent stresses were used to assess the stresses in both human bone and titanium alloy implants. The highest stress levels in bone were predicted for the case without sufficient implant sheathing. In the models with adequate bony implant support, intrabony stresses were generally reduced by up to - 40%. The structural stiffness of the bone-implant system increased with the extent of sinus floor elevation. The results indicate that more extensive peri-implant packing reduces implant displacement, intrabony stresses and stresses at the bone-implant interface.     

A synthetic bioactive resorbable graft for predictable implant reconstruction: part one

Animal studies were conducted to evaluate the cell response and chemical potentiality of a synthetic bioactive resorbable graft (SBRG) made of nonceramic cluster particulate of low-temperature HA material. The study evaluated bone-bridging of the SBRG particulates in 1-mm wide implant channels of 5 x 8 mm long roughened titanium interface in 6 dogs and compared results to the same implant channels left empty as controls at 6- and 12-week intervals. Resorption rate capacity and cell response were evaluated with an assessment of the chemical characterization of the synthetic nonceramic material next to the titanium implant interfaces. Results of the animal studies were compared with human histologic biopsies of the SBRG for bone quality, density, and bone growth into defect sites concurrent with resorption time of the graft. One human biopsy consisted of a graft mixture of the SBRG and dense bovine-derived HA, compared under the electron microscope, including histology by H and E staining. Part 1 of this paper presents evidence of the predictability and efficacy of the SBRG osteoconductive, particulate chemical potentiality to aid in the regeneration of lost bone anatomy next to titanium implant interfaces. Recent technological innovations in computer hardware and software have given clinicians the tools to determine 3-dimensional quality and density of bone, including anatomical discrepancies, which can aid in the diagnosis and treatment planning for grafting procedures. When teeth are extracted, the surrounding bone and soft tissue are challenged as a result of the natural resorptive process. The diminished structural foundation for prosthetic reconstruction, with or without implants, can be compromised. A synthetic bioactive resorbable graft material having osteoconductive biochemical and biomechanical qualities similar to the host bone provides the means to improve compromised bone topography for ridge preservation, ridge augmentation, or to enhance the bony site for implant placement and subsequent prosthetic rehabilitation. Part two of this paper will demonstrate clinical applications of the SBRG material for purposes of implant placement and prosthetic reconstruction.     

Image data based reconstruction of the midface using a patient-specific implant in combination with a vascularized osteomyocutaneous scapular flap

BackgroundSecondary reconstructions in case of complex craniofacial defects of the midface, following radical tumour surgery, often require individualized surgical techniques. To achieve a satisfying functional and aesthetic outcome various anatomical aspects have to be considered such as the architecture of the bony structures as well as the very special shape of the orbit. Bone grafting is particularly challenging under these conditions, and one single graft type can hardly fulfil all anatomical demands.The presented method aims at combining a free microvascular bone graft and a preoperatively planned patient-specific alloplastic implant which takes into account all anatomic requirements as well as a functional rehabilitation including dental restoration.Case reportBy means of the described treatment approach, complex midfacial defects are reconstructed on the base of preoperative computer-assisted three-dimensional planning, a patient-specific prefabricated implant and a free vascularized bone transplant.A three-dimensional planning platform was used to create a mirror image of the unaffected contralateral side that was superimposed on the defect side referring to a virtual sagittal plane. The planned donor site of the scapula was then virtually matched into an ideal anatomic position considering all functional and aesthetical aspects, including a later implant based prosthodontic rehabilitation. By use of these virtual outlines, an individual titanium implant was manufactured to provide both for midfacial support and a graft fixture in a position, which was close to original. Intraoperative optical navigation was used to assess the accurate position of the implant with special regard to a correct reconstruction of the orbit. An implantologic rehabilitation could be achieved.ConclusionThe technique presented offers an ideal combination of a patient-specific alloplastic implant for the reconstruction of the very demanding orbital anatomy in combination with a scapular flap offering a sufficient bone stock for an implant based prosthodontic rehabilitation.     

Materials for endosseous dental implants

summary The goal of placement of endosseous dental implants is to achieve osseointegration or biointegration of the bone with the implant. A wide variety of materials has been used for these implants, but only a few promote osseointegration and biointegration. Titanium and titanium alloy (TJ6A14V) have been the most widely used of these materials. The surface oxide of titanium appears to be central to the ability of this material to osseointegrate. The oxide limits dissolution of elements and promotes the deposition of biological molecules which allow bone to exist as close as 30 å to the surface of the implant. The details of the ultrastructure of the gap between the implant and bone remain undefined, and the consequences of elements which are released on the interface over time are not known. These areas of investigation are particularly important in defining the differences between commercially pure titanium implants and those made of titanium, aluminium and vanadium. The epithelial interface between the gingiva and titanium appears to contain many of the structural characteristics of the native tooth-gingiva interface, but details are still vague. The connective tissue interface with the titanium appears to be one of tightly fitting tissues rather than adhesion. Ceramic coatings appear to improve the ingrowth of bone and promote chemical integration of the implant with the bone. The characteristics of these coatings are complex and affect the bony response, but the mechanisms remain obscure. The degradation of the coatings is an issue of particular controversy. Progress in dental implantology is likely to continue as the interface between the material and bone is more clearly understood, and biological molecules and artificial tissues are developed.     

Three-dimensional numerical simulation of dental implants as orthodontic anchorage

Endosseous oral implants have been used as orthodontic anchorage in subjects with multiple tooth agenesis, and their application under orthodontic loading has been demonstrated clinically and experimentally. The aim of this investigation was to examine three-dimensional (3D) bone and implant finite element (FE) models. The first model assumed that there was no osseointegration and the second that full osseointegration had occurred. These models were used to determine the pattern and distribution of stresses within the ITI-Bonefit endosseous implant and its supporting tissues when used as an orthodontic anchorage unit. The study examined a threaded implant placed in an edentulous segment of a human mandible with cortical and cancellous bone.The results, using both models, indicated that the maximum stresses were always located around the neck of the implant, in the marginal bone. Thus, this area should be preserved clinically in order to maintain the bone-implant interface structurally and functionally.     

Factors affecting stresses in cortical bone around miniscrew implants: A three-dimensional finite element study

Objective:To evaluate various types of stress in cortical bone around miniscrew implants using finite element analysis.Materials and Methods:Twenty-six three-dimensional assemblies of miniscrew models placed in alveolar bone blocks were constructed using Abaqus (Dassault Systèmes Simulia Corp, Providence, RI), a commercial finite element analysis software package. The model variables included implant design factors and bone-related factors. All miniscrew implants were loaded in the mesial direction with a linear force equal to 2 N. Peak von Mises and principal stress values in cortical bone were compared between the different models for each factor.Results:The results demonstrated that some factors affected the stresses in bone (implant diameter, implant head length, thread size, and elastic modulus of cancellous bone), while other factors did not (thread shape, thread pitch, and cortical bone thickness).Conclusions:Miniscrew implant diameter, head length, and thread size as well as the elastic modulus of cancellous bone affect the stresses in cortical bone layer surrounding the miniscrew implant and may therefore affect its stability.     

正畸支抗种植体骨整合与稳定性的实验研究

目的　考察正畸支抗种植体的骨整合与稳定性以及二者之间的关系。方法　将HA涂层钛种植体、钛浆喷涂钛种植体、未涂层钛种植体植入狗股骨 ,愈合期后施加 1 96N正畸力 2个月。测量施力后种植体的位置变化和种植体—骨界面的剪切结合强度 ,用扫描电镜观察界面。结果　 3种种植体位移分别为 (- 0 5 0± 1 78)mm、(- 0 0 5± 1 76 )mm、(0 2 9± 1 77)mm ,统计学分析结果显示 ,还不能认为 3种种植体出现移动。 3种种植体—骨界面的剪切结合强度分别是 (2 88± 0 5 5 )MPa、(1 89± 0 81)MPa和 (2 14± 0 49)MPa。HA涂层种植体与骨紧密结合 ,其界面结合强度最高 ;另外 2种种植体与骨的结合强度差异无显著性。结论　虽然HA涂层种植体与骨结合最牢固 ,但 3种种植体—骨界面均可形成骨整合 ,在常规正畸力作用下不会发生明显移动。本项研究结果表明 ,种植体可用作短期的正畸支抗。     

A histologic and histomorphometric evaluation of two types of retrieved human titanium implants

This study analyzed the interfacial human bone response to retrieved implants that had been functionally loaded in the human environment. A solid-screw titanium plasma-sprayed (TPS) implant was removed 5 years after implantation because of a fracture at the joint between the implant and the crown. A sand-blasted acid-etched titanium implant (SLA) was used as an anchorage for orthodontic treatment. At the end of the treatment, the SLA implant was removed. Both types were functionally loaded without any symptoms expressed by the patients. Histology showed bone contact between the TPS or the SLA implant and surrounding bone, but the SLA implant revealed much more interfacial bone contact. The contact microradiograms showed that the bone surrounding the TPS and SLA implants was highly calcified. The measured percentage of bone-implant contact around the SLA implant was significantly higher (P <.05) than that around the TPS implant.     

Integrin mediated attachment of periodontal ligament to titanium surfaces

ObjectiveReducing the force between the implant and the bone by recapitulating a similar matrix has the potential to reduce implant failure. To begin to pursue the goal of creating a periodontal ligament interface between a dental implant and bone, the mechanism of cellular attachment to dental implant surfaces must be characterized.MethodsIn this study we examined the role of integrin receptors in the attachment of periodontal ligament fibroblasts to titanium surfaces utilized on dental implants; those surfaces included smooth polished titanium, acid pickled titanium, ground titanium, sandblasted and acid etched titanium, non-oxidized titanium that has been sandblasted and acid etched, hydroxyapatite coated titanium, titanium plasma sprayed or uncoated titanium. For these studies integrin mediated fibroblast attachment was blocked by the integrin blocking peptide GRGDSP or anti-integrin β1 antibody or a combination of the two. Quantitation of periodontal ligament fibroblast attachment was completed by counting cells on the various implant surfaces after culturing in vitro for 24 h with and without the integrin receptor blockers.ResultsAntibody and peptide treatment significantly reduced the number of fibroblasts cells attached to the various implant surfaces but this effect varied significantly depending on the surface. Moreover, increased levels of peptide further decreased fibroblasts attachment in a dose dependent manner.SignificanceBlocking studies suggest first, that integrin receptors function in periodontal ligament attachment to titanium surfaces and second, that different integrin subunits are important in attachment to a particular surface.     

Osseointegration of Orthodontic Micro-screws After Immediate and Early Loading

Objective:To investigate the desirable healing time of micro-screws by histomorphologic and histomorphometric evaluations of osseointegration after immediate and early loading.Materials and Methods:Fifty-four micro-screws were bilaterally placed in the maxillary premolar regions of nine beagles. Then the micro-screws with various healing time of 0 day (0D group), 2 weeks (2W group), and 4 weeks (4W group) were loaded with an orthodontic force (100 g) for 8 weeks. The direction of the orthodontic force was vertical to the long axis of the micro-screws. Hard tissue sections containing micro-screws were prepared for histomorphologic and histomorphometric evaluations.Results:The survival rate of the micro-screws in this study was 100%. Bone remodeling, close contact bone-implant interface, and endochondral ossification were observed in all osseous specimens. Activated osteoblasts aggregated to the bone-implant interface of the 4W group, and lamellar bone was found in the peri-implant regions. Micro-screws of the 2W group were partially surrounded by collagen fibers; and neonatal lines of bone, woven bone, and osteoclasts were found in the peri-implant regions. Micro-screws of the 0D group were surrounded by more collagen fibers compared with the other two groups. Bone implant contact ratios of the three groups were 43.74% (0D group), 66.26% (2W group), and 73.28% (4W group), respectively and statistical differences were significant (ANOVA, P < .01).Conclusion:All micro-screws in the three groups can provide stable orthodontic anchorage. However, to obtain improved stationary anchorage, a 4-week healing time is recommended before orthodontic loading.     

Finite element study on the effect of abutment length and material on implant bone interface against dynamic loading

PURPOSE

Finite element study on the effect of abutment length and material on implant bone interface against dynamic loading.

MATERIALS AND METHODS

Two dimensional finite element models of cylinderical implant, abutments and bone made by titanium or polyoxymethylene were simulated with the aid of Marc/Mentat software. Each model represented bone, implant and titanium or polyoxymethylene abutment. Model 1: Implant with 3 mm titanium abutment, Model 2: Implant with 2 mm polyoxymethylene resilient material abutment, Model 3: Implant with 3 mm polyoxymethylene resilient material abutment and Model 4: Implant with 4 mm polyoxymethylene resilient material abutment. A vertical load of 11 N was applied with a frequency of 2 cycles/sec. The stress distribution pattern and displacement at the junction of cortical bone and implant was recorded.

RESULTS

When Model 2, 3 and 4 are compared with Model 1, they showed narrowing of stress distribution pattern in the cortical bone as the height of the polyoxymethylene resilient material abutment increases. Model 2, 3 and 4 showed slightly less but similar displacement when compared to Model 1.

CONCLUSION

Within the limitation of this study, we conclude that introduction of different height resilient material abutment with different heights i.e. 2 mm, 3 mm and 4 mm polyoxymethylene, does not bring about significant change in stress distribution pattern and displacement as compared to 3 mm Ti abutment. Clinically, with the application of resilient material abutment there is no significant change in stress distribution around implant-bone interface.     

Implant-abutment interface: biomechanical study of flat top versus conical

Background: Overloading has been identified as a primary factor behind dental implant failure. The peak bone stresses normally appear in the marginal bone. The anchorage strength is maximized if the implant is given a design that minimizes the peak bone stress caused by a standardized load. Clinical studies have shown that it is possible to obtain a marginal bone level close to the crest of the implant. Different implant systems make use of different designs of the implant‐abutment interface. Different implant‐abutment interfaces imply that the functional load is distributed in different ways upon the implant. According to Saint‐Venant's principle, this will result in different stress patterns in the marginal bone when this reaches levels close to the implant crest. Purpose: One aim of the study was to theoretically investigate if a conical implant‐abutment interface gives rise to a changed stress pattern in the marginal bone, as compared to a flat top interface, for an axially loaded mandibular titanium implant, the neck of which is provided with retention elements giving effective interlocking with the bone. Further aims were to investigate if the way in which the axial load is distributed on the flat top and on the inner conus respectively affects the stress pattern in the marginal bone. The pertinent stress was considered to be the bone‐implant interfacial shear stress. It was assumed that the marginal bone reached the level of the implant–abutment interface. Method: The investigation was performed by means of axisymmetric finite element analysis. Results: The conical implant‐abutment interface of the type studied brought about a decrease in the peak bone‐implant interfacial shear stress as compared to the flat top interface of the type studied. This peak interfacial shear stress was located at the top marginal bone for the flat top implant‐abutment interface whereas it was located more apically in the bone for the conical implant‐abutment interface. The way in which the axial load was distributed on the flat top and on the inner conus respectively affected the peak interfacial shear stress level. Conclusion: The design of the implant‐abutment interface has a profound effect upon the stress state in the marginal bone when this reaches the level of this interface. The implant with the conical interface can theoretically resist a larger axial load than the implant with the flat top interface.     

支抗种植体外形影响骨界面应力分布的研究

目的探讨种植体外形差异对骨界面应力分布的影响，并筛选出最佳支抗种植体外形。方法应用三维有限元分析方法对刃状螺纹型、矩形螺纹型及光滑型种植体进行骨界面应力和位移分析。结果刃状螺纹型种植体做支抗体时其骨界面第一、第二及第三主应力分别为6.67MPa、1.47MPa及0.52MPa，并且VonMises应力为7.22MPa，在三种种植体中应力值最小。而3种种植体颈部牙槽骨的DMX位移值分别为0.11×10     

紫外线光功能化对二氧化钛纳米管表面改性钛种植体骨结合的影响

目的 研究紫外线光功能化对二氧化纳米管钛表面改性钛种植体骨结合的影响。方法 采用预阳极氧化法制备二氧化钛（TiO₂）纳米管表面改性钛种植体，并用波长为250 nm、功率为2mW/cm²紫外线（UVA）对种植体进行处理。将种植体植入SD大鼠股骨，12周后取含种植体骨组织制作组织切片，通过显微镜观察种植体周围骨组织形成情况并计算骨结合率。结果UVA处理组种植体周围新生骨组织多于未UVA处理组，且更致密。UVA处理组和未UVA处理组的骨结合率分别为（72.21±10.42）%和（44.98±9.62）%，两组之间的差异具有统计学意义（P<.05）。结论UVA光功能化TiO₂纳米管表面改性有助于促进钛种植体骨结合。     

Structure of the bone‐titanium interface in retrieved clinical oral implants

7 clinically stable, "osseointegrated", titanium implants, inserted in human jaws for l–16 years, were retrieved for morphological analysis of the bone‐titanium interface, using 3 different preparation techniques. The bone‐titanium interface varied as judged from light microscopy of ground sections. The threads of the implants were well filled 79–95% with dense lamellar bone as quantified with morphometry. A large fraction of the implant surface (56–85%) appeared to be in direct contact with the mineralized bone. In general, the non‐boric areas consisted of pockets with osteocytes, bone marrow tissue and/or vessels. Sections were prepared for light microscopy and transmission electron microscopy using a fracture technique. where the implant was separated from the embedded tissue before sectioning, and an electropolishing technique, where the bulk part of the implant was electrochemically removed. In areas judged as direct mineralized bone‐titanium contact in the light microscope. the interfacial structure varied at the ultrastructural level. In areas along the interface, unmineralized tissue was present either as a narrow 0.5–l μm wide zone containing collagen fibril or as deeper pockets containing osteocytes or vessels. In areas with mineralized bone contact. an amorphous granular layer (100–400 nm wide) with no mineral was observed in the innermost interface bordering the mineralized bone, with an electron‐dense lamina limitans‐like line (approximately 50 nm thick). It is concluded that the bone‐titanium interface of the 7 clinically retrieved titanium oral implants examined in the present study bone was heterogenous. In areas of a direct mineralized bone‐titanium contact at the ultrastructural level. mineralized bone reached close to the implant surface, but was separated by an amorphous layer. 1 being 100–400 nm thick.     

Surface analysis and effects on interfacial bone microhardness of collagen-coated titanium implants: a rabbit model

PURPOSE: The aim of this study was to evaluate the surface chemistry and the microhardness at the implant-bone interface using a recently developed collagen-coated titanium implant in a short-term rabbit model. MATERIALS AND METHODS: Surface chemistry was evaluated by x-ray photoelectron spectroscopy (XPS), while in vivo studies involved 4-week implants mid-diaphysis in the lateral femurs of adult male rabbits. After conventional embedding and evaluation of histologic sections, the resinembedded blocks containing the implanted screws were used to measure bone hardness by means of an indentation test. RESULTS: Decomposition of the C1s peak obtained by XPS analysis confirmed that surface-immobilized collagen retained all the molecular features of the control, nonimmobilized reference. As to microhardness measurement, newly formed bone at the collagen-coated-implant/bone interface was significantly harder than bone at the interface of the uncoated control implant and bone. DISCUSSION: These results suggested that collagen coating significantly improves bone maturation and mineralization at the interface in comparison with uncoated commercially pure titanium. Surface modification of titanium implants by collagen coating has recently been discussed as a promising approach to the biochemical modification of implant surfaces. The present results support previous histologic findings and demonstrated that the biomolecular layer linked over the titanium implant can increase the bone healing rate, at least in this animal model. CONCLUSIONS: The present microhardness measurement at the bone-implant interface showed that collagen coating can significantly improve bone maturation and mineralization at the interface in comparison with uncoated commercially pure titanium, confirming and substantiating previous findings by histomorphometric measurements from the same model.     

Histomorphometric assessment of implant coated with mixture of nano-alumina and fluorapatite in rabbits

BackgroundThe application of nanoscale surface modification was found to be useful in the improvement of osseointegration of endosseous dental implants. The fluorapatite (FA)/alumina (Al₂O₃) mixture is recognized for its outstanding bioinertia and can significantly increase the biocompatibility and bioactivity of biomaterials.ObjectiveThe aim of the present work was to evaluate the bone response to nano-alumina- and fluorapatite-coated dental implants using rabbit tibiae.Material and MethodsThe coating was performed using the dip-coating method. Commercially pure titanium screw-type implants were used as a control group. The coated implants were the experimental group. Each group consisted of 12 screws that were surgically implanted in 6 healthy New Zealand rabbits. Histological and histomorphometric evaluations were performed at the bone to implant contact (BIC) interface, bone fraction area occupancy (BAFO) and fibrous tissue at 2 and 6 weeks of healing.ResultsThis analysis showed that the coated implants had more rapid osseointegration than the control group, with a significant difference after 2 and 6 weeks of healing for both groups. The histomorphometric evaluation demonstrated higher values for BIC% and BAFO% and lower values of fibrous tissue in the mixture-coated Ti implants than in the control group.ConclusionThe current study suggested that the nano-alumina and fluorapatite mixture coating is a favourable candidate for rapid osseointegration over uncoated implants.     

不同粗糙表面的纯钛种植体与骨组织界面剪切强度的评价

目的:通过测定不同粗糙度的种植体在不同植入时间的剪切强度的变化,评价不同粗糙度种植体与骨的结合强度。方法:将纯钛的光滑试样、微粗糙表面(I)、微粗糙表面(II)、大粗糙表面等四组植入家兔股骨中,分别在术后一个月和三个月将种植体连同周围的骨组织切下来,进行拉出试验。结果:随着种植体表面粗糙度的增大,界面剪切强度呈增大。随着植入时间的增加,界面剪切强度也呈增大趋势。结论:对于纯钛,不同表面粗糙度的种植体-骨组织界面的剪切强度有明显的差异,随着粗糙度的增大,剪切强度也随之增大;随着植入时间的增加微粗糙与粗糙表面的剪切强度趋向接近。