Implants placed in an irradiated dog mandible: a morphometric analysis

The objective of this research was to evaluate the influence of radiotherapy on the osseointegration of oral implants in a canine model. After the extraction of all mandibular premolars and first and second molars, 11 male beagles were divided into 3 groups. The control group (3 dogs) received no radiation. The second group (4 dogs) was irradiated 4 weeks after implantation. The third group (4 dogs) was irradiated 8 weeks before implantation. Eight implants were placed in each dog, in an alternating pattern: 4 non-submerged ITI Bonefit titanium plasma spray-coated and 4 submerged Steri-Oss hydroxyapatite-coated. The irradiated dogs received 4.3 Gy daily for 10 days. After 6 months of osseointegration, the dogs were sacrificed and each hemimandible was dissected to isolate the implants. Quantification of the extent of the direct bone-implant contact was carried out by scanning electron microscopy backscattered electron images that reproduced each implant in its entirety, using a digitizing table connected to a computer. The results were expressed as a percentage of direct bone-implant contact versus total perimeter accessible to bone. The bone contact percentage for the control group was 87% for Steri-Oss implants and 69% for the ITI Bonefit implants; for the animals irradiated after implantation, the percentages were 82 for Steri-Oss implants and 58 for ITI Bonefit implants; and for the animals irradiated before implantation, the percentages were 62 for Steri-Oss implants and 28 for ITI Bonefit implants. A statistically significant difference appeared between the 2 types of implants (P < .001). A statistically significant difference was also seen between the 3 groups for both types of implants, except between the control group and the group irradiated after implantation (P = .14). This indicates that, overall, the timing of irradiation influences osseointegration. Osseointegration is possible before and after radiotherapy; however, the direct bone-implant contact increased when the implants were placed before irradiation.     

Histomorphometric study of ion implantation and diamond-like carbon as dental implant surface treatments in beagle dogs

PURPOSE: Improvements in the bone-implant interface can provide clinical benefits, such as increasing the amount of bone in contact with the implant and shortening the time required to achieve sufficient bone appositioning to allow early prosthetic loading. The present study describes the results obtained with 2 new surface treatments: (a) CO ion implantation; and (b) diamond-like carbon (DLC) coating. MATERIALS AND METHODS: Each group (ion implantation, DLC, and the control group, turned titanium) consisted of 12 samples. Beagle dogs subjected to previous partial edentulation were used. Dual histologic evaluation was made of percentage bone-implant contact (% BIC) of all samples based on conventional histomorphometric analysis and environmental scanning electron microscopy (ESEM). RESULTS: The results obtained after 3 and 6 months of dental implant placement showed greater and faster bone integration in the CO ion implantation group (61% and 62% BIC, respectively) compared with the DLC group (47% and 50%); the data corresponding to the ion implanted samples were statistically significant compared with the control group (33% and 49% BIC after 3 and 6 months, respectively). CONCLUSIONS: The results showed improved % BIC for implants with ion-implanted surfaces in comparison to DLC coating and machined controls. Furthermore, bone integration appeared to be accelerated in the ion implantation group, since high % BIC values were recorded in the early stages after in vivo implantation.     

Histomorphometric analysis of the osseointegration of four different implant surfaces in the femoral epiphyses of rabbits

Objectives: The surface properties of titanium dental implants are key parameters for rapid and intimate bone–implant contact. The osseointegration of four implant surfaces was studied in the femoral epiphyses of rabbits. Material and methods: Titanium implants were either grit‐blasted with alumina or biphasic calcium phosphate (BCP) ceramic particles, coated with a thin octacalcium phosphate (OCP) layer, or prepared by large‐grit sand blasting and acid‐etched (SLA). After 2 and 8 weeks of implantation, the bone‐implant contact and bone growth inside the chambers were compared. Scanning electron microscopy (SEM) and profilometry showed distinct microtopographies. Results: The alumina‐Ti, BCP‐Ti and OCP‐Ti groups had similar average surface roughness in the 1–2 μm range whereas the SLA surface was significantly higher with a roughness averaging 4.5 μm. Concerning the osseointegration, the study demonstrated a significantly greater bone‐to‐implant contact for both the SLA and OCP‐Ti surfaces as compared with the grit‐blasted surfaces, alumina‐ and BCP‐Ti at both 2 and 8 weeks of healing. Conclusion: In this animal model, a biomimetic calcium phosphate coating gave similar osseointegration to the SLA surface. This biomimetic coating method may enhance the apposition of bone onto titanium dental implants.     

Quantitative analysis of dental porcelain surfaces following different treatments: correlation between parameters obtained by a surface profiling instrument

This investigation compared, by quantitative analysis, the surface roughness of dental porcelain submitted to three different treatments (glaze, trimming and polishing), utilizing a surface profiling instrument. The parameters Ra (median roughness), Rz (median of the maximum profile heights of five sample lengths), Rpm (median of the maximum profile heights related to the median line of five sample lengths), Pc (peak count per centimeter) and Rpm/Rz (proportional parameter) were evaluated. In addition, the correlation between Ra and the other parameters was analyzed. Based on the results obtained, it was seen that the Ra parameter did not present any correlation with the other parameters in some of the situations evaluated. This demonstrates that complementation of the measurement with other parameters is always necessary, providing a better evaluation of the functional properties of a surface.     

不同表面处理方法对CAD/CAM氧化锆种植体表面显微形貌的影响研究

目的：：研究采用不同表面处理方法对CAD/CAM氧化锆种植体表面显微形貌特征及粗糙度的影响。方法：通过CAD/CAM技术加工氧化锆圆盘与一段式氧化锆种植体( Y-TZP, WIELAND),根据表面处理方式分为终烧结表面、喷砂表面及喷砂加热酸蚀处理表面;标准对照组选用BEGO钛种植体表面。各组圆盘试件及种植体用扫描电子显微镜及Keyence 3D激光显微形貌测量显微镜进行表面显微形貌观察与测量。采用单因素方差分析比较各组统计学差异。结果：各组CAD/CAM氧化锆试件表面显微形貌观察显示,喷砂后表面出现边缘锐利的凹坑及沟槽;喷砂加热酸蚀处理后,氧化锆表面可见纳米级的微小孔隙及沟纹。氧化锆种植体粗糙度测量结果显示：终烧结组的表面粗糙度值(Ra=0.69μm)显著低于其他3组(P<0.001),喷砂组Ra值(Ra=1.30μm)显著低于喷砂加热酸蚀组(Ra=1.49μm)及BEGO钛种植体组(Ra=1.57μm)(P<0.01),而喷砂加热酸蚀组与BEGO钛种植体组则无显著差异(P=0.196)。结论：CAD/CAM氧化锆试件终烧结后喷砂或喷砂加热酸蚀处理均可获得较为理想的表面粗糙度,热酸蚀处理能够改变氧化锆表面的纳米级微观结构。     

Resonance frequency measurements of implant stability in the dog mandible: experimental comparison with histomorphometric data

The aim of the present study was to test the hypothesis that measurements of implant stability using resonance frequency analysis (RFA) correlate with histomorphometric data of bone anchorage. Ten adult female foxhounds received a total of 80 implants in their mandibles 3 months after removal of all premolar teeth. At the time of implant placement, torque required for bone tapping was registered as a measure of bone density and immediately after placement implant stability was assessed using RFA. RFA measurements were repeated at the time of implant retrieval after 1 month (5 dogs) and 3 months (5 dogs). Peri-implant bone regeneration was assessed histomorphometrically by measuring bone-implant contact (BIC) and the volume density of the newly formed peri-implant bone (BVD). RFA values at the time of implant placement did not correlate with the torque required to tap the bone for implant placement. After 1 and 3 months, RFA values were significantly increased compared with baseline values. BIC and BVD, however, had increased significantly during this interval. There was no correlation between bone-implant contact and RFA values nor between peri-implant bone density and RFA values. Thus, the hypothesis could not be verified. It is concluded that the validity of the individual measurement of implant stability using RFA should be considered with caution.     

Histomorphometric analysis of implant osseointegration using hydrophilic implants in diabetic rats

Clinical Oral Investigations - To evaluate peri-implant bone formation of titanium implants using an in vivo rat model with and without uncontrolled diabetes mellitus (DM) to evaluate...     

螺旋形种植体弹性模量与骨界面应力分布关系的三维有限元分析

目的：分析螺旋形种植体弹性模量与骨界面应力分布的关系。方法：用三维有限元法对不同弹性模量种植体在各种载荷下骨界面的应力大小和分布进行分析。结果：种植体周围界面骨组织应力强度随着材料弹性模量的增大而增大。结论：低弹性模量的钛合金材料作为种植材料时具有更好的生物力学相容性。     

计算机辅助设计制作下颌All-on-4种植义齿光弹模型

目的:探讨采用计算机辅助技术设计制作远中种植体具有不同倾斜角度的无牙颌下颌骨All-on-4种植义齿光弹模型的方法。方法:CT扫描无牙颌下颌骨标本,用Mimics及Geomagic Studio软件进行无牙颌下颌骨三维模型重建及编辑修改;设计种植体植入位点,具体为前牙区2只种植体设计为垂直植入,根据远中2只种植体的不同倾斜角度(0°、15°、30°、45°)将模型分为4组;用光固化快速成型技术加工制作出模块化树脂模型并翻制硅橡胶阴模,常规方法制得远中种植体具有不同倾斜角度的All-on-4种植义齿光弹模型。结果:制得的All-on-4种植义齿光弹模型质地均匀,呈淡黄色,透明度高,光学敏感度高,无初应力。结论:采用计算机辅助技术设计制作光弹模型的方法,简化了操作步骤,重复性好。     

Chemical and topographical surface analysis of five different implant abutments

The surface characteristics of the dental implant abutment which penetrates through the gingival mucosa and is exposed to the oral cavity play an important role not only for the biocompatibility but also for the bacterial adhesion and stagnation. The purpose of this study was to investigate the surface characteristics of 5 commercially available implant abutments which were Brånemark (Nobel Biocare, Gothenburg, Sweden), Astra (AstraTech, Mölndal, Sweden), IMZ (Friatec, Mannheim, Germany), STERI‐OSS (Denar, CA, USA) and POI (Kyocera, Kyoto, Japan). The three dimensional imaging and analysis of the surface topography were carried out using a confocal laser scanning profilometer (TopScan 3D). The chemical composition of abutment surfaces was analyzed by Auger Electron Spectroscopy (AES). The results indicated that quite different surface features were shown in three dimensional images. These features reflected roughness parameters. S_a and S_cx values of these abutments in μm were Brånemark (0.23±0.09, 7.76±0.64), Astra (0.23±0.05, 7.92±0.25), IMZ (0.18±0.03, 7.76±0.80), STERI‐OSS (0.15±0.01, 10.22±0.90) and POI (0.24±0.01, 8.08±0.77), respectively. The chemical elemental analysis showed all specimens to have thin titanium oxide layers (approximately 4 to 7 nm) except POI which is anodized titanium alloy, hence it has rather a thick oxide layer (95 to 110 nm). Some minor elemental traces (S, Si and P) were also seen on the outermost layer. The specimens which were investigated in this study varied in their topography and elemental composition. These variations were strongly due to the manufacturing processes which were milling, polishing, cleaning and sometimes oxidation methods.     

3-D analysis obtained in mandible movements in children 7-15 years old with different types of occlusion

60 children with different types occlusion--normal, distal, mesial and transverse between the ages 7-15 years were selected. Using unique computer software programme and 3D digitizer MicroScribe-G2 (Company Immersion, USA) on the articulator with mounted casts, persuaded measuring the scores in different movements of mandible habitual occlusion, maximum forward movement and maximum lateral movements. Scores were calculated and results interpreted.     

Immediate loading after implant placement following tooth extraction up-regulates cellular activity in the dog mandible

Objectives: The aim of this study was to investigate cellular activity of the cervical portion of peri‐implant tissue due to immediate loading after implant placement following tooth extraction from the dog mandible, in terms of morphological, immunohistochemical and molecular characteristics. Material and methods: A sand‐blasted implant was inserted into the root septum bone of each extraction socket and was connected to a superstructure made from resin and then covered with an expanded polytetrafluoroethylene membrane. Implants without the superstructure were used as the non‐loading control group. Animals were sacrificed 1–3 weeks later and specimens were observed using light microscopy and mRNA levels were analyzed by real‐time polymerase chain reaction. Results: The new bone formation ratio in the loading group at 3 weeks was significantly higher than in the non‐loading group. Alkaline phosphatase (ALP)‐positive cells were observed in tissues around the implant surface in both groups at each of the time periods. More osteocalcin (OCN)‐positive cells were observed in the non‐loading group than in the loading group at 2 weeks. The expression of ALP mRNA in the loading group was significantly up‐regulated compared with the non‐loading group (P<0.05). The expression of OCN mRNA in the loading group was significantly up‐regulated compared with the non‐loading group at 2 weeks (P<0.05). Conclusion: These results suggest that immediate loading after implant placement following tooth extraction osteogenic affects cellular activity of cervical portion of peri‐implant tissue. To cite this article:
Sato R, Matsuzaka K, Kokubu E, Inoue T. Immediate loading after implant placement following tooth extraction up‐regulates cellular activity in the dog mandible.
Clin. Oral Impl. Res. xx , 2011; 000–000.
doi: 10.1111/j.1600‐0501.2010.02118.x     

不同粗糙表面的纯钛种植体表面的体外细胞培养评价

目的：本文通过对不同粗糙度表面纯钛种植体（光滑、机械表面、大粗糙表面、2种不同的微粗糙表面）的体外细胞培养评价,寻找具有较好的细胞附着的表面状态。方法：对5种不同粗糙度的钛种植体表面进行2BS成纤维细胞培养,通过光镜和电子显微镜对材料表面的成纤维细胞的数量和形态、细胞的粘附状态和细胞与种植体的关系进行了观察和分析。结果：粗糙表面的钛种植体对成纤维细胞的＂诱导能力＂更强,表现为细胞迁徙、附着于二者的细胞数目比光滑表面的钛板为多,细胞桥形成更早。结论：钛种植体表面微粗糙化提高钛材的生物相容性。     

Physico-chemical characterization of the surface of 9 dental implants with 3 different surface treatments

There are many surface treatments applied to dental implants. The aim of the present investigation is to compare the physicochemical characteristics of titanium dental implant surfaces with different surface treatments. 9 dental implants from the same batch were divided in 3 groups and received 3 different surface treatments: machined, acid etched and a new chemical surface treatment called Avantblast. Scanning electron microscopy and confocal microscopy were used to image the treated surfaces, and energy-dispersive spectrometry and X-ray photoelectron spectrometry to provide a chemical characterization of the surfaces. RESULTS: The acid etched and chemical etched surfaces had an increased roughness over the machined one. Surface chemical composition had differences between processes, as the surface with the new treatment presented a reduced level of impurities and increased thickness of the titanium oxide layer. CONCLUSIONS: Surface roughness of titanium dental implants and thickness of the titanium oxide layer can be increased with a suitable surface treatment.     

微创种植固定修复在下颌无牙颌患者中的临床应用研究

目的：通过在下颌微创种植8枚种植体,使下颌无牙颌患者获得固定义齿。方法：对下颌无牙颌要求种植固定义齿的患者进行筛选,制定详细的治疗方案。采用不翻瓣的手术方法植入8枚种植体,对患者原义齿缓冲后做过渡使用。术后6个月采用黏固式分段烤瓷桥的设计方式修复完成至少12牙单位修复。结果：本院自2006年至2013年期间采用此方法对下颌无牙颌患者完成种植固定义齿修复18例,追踪期（0.8-7年）内,种植体存留率100%,种植体周围组织稳定,义齿局部崩瓷一例。结论：下颌无牙颌患者8枚种植体支持的固定义齿咀嚼功能恢复理想,患者使用舒适方便,义齿卫生易于维护,患者接受度和满意度高。