Human study of ion implantation as a surface treatment for dental implants

This clinical study evaluated a new surface treatment of ion implantation with CO ions which has previously been subjected to extensive study in animal models. The aim of this work was to assess its effect in humans. Experimental mini-implants were used; half of their longitudinal surface was machined and the other half was treated with CO ion implantation. The study was conducted in healthy volunteer patients who required prosthetic treatment with dental implants, and in accordance with the corresponding ethics committees. Coinciding with the insertion of commercial implants for oral restoration, one or two mini-implants were placed in the upper maxillary tuberosity or in the retromolar trigone of the mandible. The mini-implants were removed with a trephine jointly with a small volume of surrounding bone after a 3-month period. Two evaluation methods were used and both showed a greater degree of bone integration in the mini-implant section that underwent CO ion implantation treatment in comparison with the non-treated surface: 62.9% vs. 57.9%, and 54.8% vs. 46.2%. In addition, no adverse reactions were observed in the surface treatment with CO ion implantation. These results confirm the positive benefits in humans, based on the findings obtained from previous animal experiments.     

Histomorphometric evaluation of guided bone regeneration around implants with SLA surface: an experimental study in beagle dogs

The aim of this study was to evaluate the efficacy of collagen membranes, either alone or combined with a human demineralized freeze-dried bone allograft (DFDBA) or natural bovine bone graft, in bone defects around dental implants with an SLA (sand-blasted, large grit, acid-etched) surface. The experiments were carried out in three beagle dogs using a split-mouth design. On one side of the jaw, three implants were placed and intra-bony defects were created and covered with a collagen membrane, randomly combined in two of the defects with human DFDBA or inorganic bovine bone graft. A control implant, without membrane covering or defect filling, was also placed. On the other side of the jaw, three implants were placed and the bone defects were treated in a similar fashion, but without membrane covering. The studied variables were the percentage of bone-to-implant contact within the limits of the initial bony defect and percentage of the original bony defect occupied by bone tissue. Although no statistically significant differences were found in this study between the membrane and nonmembrane groups, bone defects augmented with anorganic bovine bone and membranes showed the most promising results from a histological and histomorphometric perspective.     

即刻种植的动物实验研究

目的 探讨更加完善成熟的即刻种植技术和方法。方法 在拔除狗的下颌双尖牙的同时,必植入人工种植体,并在牙种植体和拔牙窝间填塞自制的ＨＡ－ｒｈＢＭＰ２－ＦＳ复合材料。以正常牙齿周围牙槽骨作对照,通过Ｘ线及组织学方法观察不同时期和种植部位骨缺损的修复及骨整合情况。并用图像分析技术分析种植界面处新骨形成量。结果 植入复合人工骨后,种植体４～８周时骨缺损修复基本完成,种植体骨整合形成,１２周时已形成坚实的骨     

Improvement of osseointegration of titanium dental implant surfaces modified with CO ions: a comparative histomorphometric study in beagle dogs

The aim of this study was to compare carbon-oxygen (CO) ion implantation as a surface treatment with diamond-like carbon and commercially treated implants, including double acid-etched (Osseotite), oxidized (TiUnite) and sandblasted and acid-etched (SLA), using machine-turned titanium implants as control. A total of 72 dental implants divided into 6 groups were placed in the mandibles of 12 beagle dogs. Evaluation was performed by conventional light transmission microscopy and environmental scanning electron microscopy (ESEM). The histological results obtained via ESEM demonstrated bone-implant contact percentage (%BIC) for implants treated with CO ion implantation of 61% and 62% at 3 and 6 months, respectively. At the same time points, the values were 48% and 45% for double acid-etched, 46% and 52% for sandblasted and acid-etched, 55% and 46% for oxidized, and 33% and 49% for machine-turned titanium control implants. Values of %BIC were statistically significantly higher in implants treated with CO ion implantation compared to the commercially treated implant group (p=0.002 and p=0.025) and the control implants (p=0.001 and p=0.032) at 3 and 6 months, respectively. No significant differences were observed between the three groups of commercially treated implants. The larger %BIC of the ion-implanted group was observable at an early stage.     

口腔种植体Beagle犬动物模型的建立

目的:以延期和即刻两种方式建立种植体植入Beagle犬下颌骨的动物模型,用以比较研究延期与即刻两种种植方式的种植体周围组织状况差异。方法:选用纯系动物Beagle犬四只,分为两组:延期种植(A组),即刻种植(B组),分别以延期和即刻两种方式将种植体植入Beagle犬下颌骨,并对两种方式植入的种植体进行mPLI、PD、松动度、GI及骨吸收量的比较。结果:种植体植入顺利,种植体植入后均稳固,各项临床检测指标无统计学差异。结论:成功建立延期种植与即刻种植的口腔种植体Beagle犬动物模型,尚不能定论即刻与延期哪种种植方式更好,临床种植方式的选择还需结合临床具体情况,严格控制适应症。     

Radiographic evaluation of dental implants with different surface treatments: an experimental study in dogs

PURPOSE: The aim of the study was to radiographically measure the bone density at the peri-implant region after osseointegration and to compare the relative bone density achieved by different surface-treated implants. MATERIALS AND METHODS: Four different types of implant surfaces were compared, using five young-adult male mongrel dogs. The first, second, third, and fourth lower premolars were extracted. Ninety days after removal, four 3.75-mm diameter and 10-mm long screw implants (Paragon) were placed with different surface treatments in the lower hemiarches. The dogs received two implants each of the following surface treatments: 1) smooth (machined); 2) titanium plasma spray: 3) hydroxyapatite coating; and 4) sandblasting with soluble particles. The implants were maintained unloaded for 90 days. After this period, the animals were killed and the hemimandibles were extracted and radiographed. The grey level of the bone adjacent to implants was measured with a specific software tool (line histogram) and the relative bone density was calculated. RESULTS: The four different surface treatments promote different numeric levels of bone density around the dental implants (sandblasting with soluble particles, 52.45 +/- 2.95; titanium plasma spray, 53.98 +/- 3.67; machined, 55.78 +/- 3.06, and hydroxyapatite coating, 58.2 +/- 2.71). Therefore, the implants can be ranked in terms of relative bone density from high to low as follows: sandblasting with soluble particles, titanium plasma spray, machined, and hydroxyapatite coating. There were no statistically significant differences in bone density among the four groups (P = 0.1130, analysis of variance). CONCLUSION: Surface treatments that add roughness to the implant show numerically higher bone density when compared with machined surfaces. The findings of radiographic density analysis suggest that the soluble blasting media-treated surface provides a greater bone density at the peri-implant region.     

愈合期微型种植体-骨界面的组织形态学研究

目的研究微型种植体-骨界面在不同愈合时间下的组织形态学变化。方法应用种植钉30枚,新西兰大白兔10只。采用HE染色方法,骨磨片方法对种植体-骨界面的横纵断面进行观察。结果种植体-骨界面在愈合1、2周时界面机化,以胶原纤维包绕为主;界面在4周时表现为复合骨;愈合8周时层状骨为主,出现二次改建。结论在家兔胫骨内纯钛微种植体骨钉骨整合可在8周内完成。     

羟基磷灰石涂层—钛基牙种植体的动物植入实验

将５６枚等离子喷涂羟基磷灰石涂层－钛基牙种植体植入狗股骨干。分别在术后１、２、３、４个月时制取不脱钙标本切片，作组织学观察、显微Ｘ线摄影及计算机辅助植体－骨接触率测量。     

beagle犬埋植型与非埋植型种植义齿骨组织界面改建的组织学观察

目的 :检测埋植型与非埋植型种植体在义齿修复受载后组织学反应的异同。方法 :选用纯系动物beagle犬 8只 ,在其下颌分别植入埋植型与非埋植型种植体 ,采用固定金属全冠行种植义齿修复 ,分不同程期处死动物。采用HE染色对埋植型与非埋植型种植体 -骨界面改建过程进行动态观察 ,比较两者之间的异同。结果 :组织学观察发现 ,种植义齿受载后 ,种植体周围骨组织发生改建。 2周时其界面绝大部分呈直接骨结合 ,但在界面处尤其螺纹顶部出现骨吸收 ,骨组织由纤维组织替代 ;4周时种植体 -骨界面结合良好 ,在界面处出现的纤维组织已逐渐通过改建形成新骨 ;8周时种植体与骨组织直接接触呈骨性界面 ,界面区细胞成分和毛细血管减少 ;12周时所有种植体与骨组织均为骨性结合界面 ,结合程度较高 ,界面区出现典型的哈弗系统。所有埋植型和非埋植型种植体之间无显著差异。结论 :非埋植型种植体与埋植型种植体均获得良好的骨结合。埋植型和非埋植型种植义齿受载后其界面的改建之间无显著差异。     

Osseo-integration of dental implants in radiated mandibles: an experimental study with beagle dogs

This investigation was planned to detect the ability of radiated bone to integrate with dental implants and to study the load-bearing capacity of these implants. In five beagle dogs, the premolars were extracted, after which one side of the mandible was radiated with 40 Gy. Three months later, two hollow-cylinder implants were placed on each side of the mandible. After a three-month period of osseo-integration, bridges were constructed on the implants, and they were loaded for six months. Both clinical and x-ray examinations showed that all implants had integrated well and bore load without change in their host sites for a six-month period, at which time the dogs were killed.     

Histomorphometric analysis of the bone-implant contact obtained with 4 different implant surface treatments placed side by side in the dog mandible

PURPOSE: The different implant systems available today present several types of surface treatment, with the aim of optimization of bone-implant contact. This study compared 4 different types of implant surfaces. MATERIALS AND METHODS: The first, second, third, and fourth mandibular premolars were extracted from 5 young adult mongrel male dogs. Ninety days after removal, four 3.75-mm-diameter, 10-mm-long screw-type implants (Paragon) were placed with different surface treatments in mandibular hemiarches. The dogs received 2 implants of each of the following surface treatments: smooth (machined), titanium plasma spray (TPS), hydroxyapatite coating (HA), and sandblasting with soluble particles (SBM). The implants were maintained unloaded for 90 days. After this period, the animals were sacrificed, and the hemimandibles were extracted and histologically processed to obtain non-decalcified sections. Two longitudinal ground sections were made for each implant and analyzed under light microscopy coupled to a computerized system for histomorphometry. RESULTS: The following means were obtained for bone-implant contact percentage: machined = 41.7%, TPS = 48.9%, HA = 57.9%, and SBM = 68.5%. DISCUSSION: The means for all treatments that added roughness to the implant surface were numerically superior to the mean found for the machined surface. However, this difference was statistically significant only between groups SBM and machined (Tukey test, P < .05). CONCLUSIONS: The SBM-treated surface provided a greater bone-implant contact than a machined surface after 90 days without loading in this model.     

应用BMSCs/A-PCPC复合物进行种植前牙槽嵴保存的实验研究

目的:建立种植前牙槽嵴保存的动物模型,观察应用组织工程骨进行牙槽嵴保存的效果。方法:抽取Beagle犬骨髓,体外分离培养、成骨诱导、扩增骨髓基质细胞(bone marrow stromal cells,BMSCs),准备活性磷酸钙骨水泥(activeporous calcium phosphate cement,A-PCPC),体外构建骨髓基质细胞/活性磷酸钙骨水泥复合体(BMSCs/A-PCPC)的复合物。拔除4只Beagle犬双侧下颌第二、三、四前磨牙,随机选取一侧植入BMSCs/A-PCPC复合物作为实验组,另一侧作为对照组(空白对照组、自体骨组、单纯A-PCPC组)。于术后1 d及术后4、12周进行X线片观察及CT扫描分析。并于12周时取牙槽窝组织,进行组织学观察,采用SPSS17.0软件包对数据进行统计学分析。结果:术后4周X线片观察,BMSCs/A-PCPC复合物组较单纯A-PCPC组、自体骨组密度高。12周时硬组织切片检测,BMSCs/A-PCPC复合物组成骨活性高于其他各组。螺旋CT分析结果显示,各组牙槽嵴均发生了不同程度的吸收。12周时,A-PCPC组牙槽嵴高度的减少值较对侧的单纯A-PCPC组、自体骨组、空白组牙槽显著降低(P<0.05)。结论:建立的种植前牙槽嵴保存的动物模型合理可行,BMSCs/A-PCPC复合物可以作为种植前牙槽嵴保存的组织工程骨材料。     

Histomorphometric evaluation of six dental implant surfaces after early loading in augmented human sinuses

This study investigated the bone-to-implant contact (BIC) and osteoconductive capacity (OC) of 6 different implant surfaces after early loading in humans. Two implants with different surfaces were placed side-by-side in the grafted (n= 5) and nongrafted (n = 1) sinuses of 3 volunteers. Single-tooth restorations were delivered 60 days later. After 6 months of full occlusal loading, implants were retrieved in block sections for histomorphometric analysis. One implant (acid etched) placed in grafted bone failed when loaded. There were no other complications. In grafted bone, the microtextured surface achieved the highest BIC value (94.08%), followed by the oxidized (77.32%), hydroxyapatite (HA) (74.51%), sandblasted and acid-etched (51.85%), and titanium plasma-sprayed (TPS) (41.48%) surfaces. In native bone, the acid-etched surface achieved a higher BIC value (69.03%) than the HA surface (59.03%). The highest OC value in grafted bone was exhibited by the microtextured surface (34.31%), followed by the HA (28.62%), sandblasted and acid-etched (25.08%), oxidized (17.55%), and TPS (-20.47%) surfaces. The HA surface exhibited a higher OC value (30.39%) in native bone compared with the acid-etched surface (24.0%). As a whole, highest BIC and OC values were exhibited by the microtextured surface, and lowest values were exhibited by the TPS surface. All other surfaces demonstrated excellent BIC (>50%) but varied in OC (range = 17.55%-28.62%). These findings are tempered by the limited scope and sample size of the study and should be considered preliminary. More research is needed to determine the impact of implant surface texture on BIC and OC.     

Titanium endosteal dental implants in the mandibles of beagle dogs: a 2 year study.

Forty of 44 vented endosteal blade implants were well tolerated by the mandibular tissues of beagle dogs, as demonstrated clinically, radiographically, and histologically. Infection and inflammation were not observed. The epithelium did not invade along the neck of the implants more than 2 mm. below the mandibular crest. After 3 to 6 months, except for increasing density of bone at the metal interface, no distinct pattern of reaction could be discerned histologically. Except for heavy collagenous investment in three dogs, there was no sign of the implants being treated as sterile foreign bodies. In this study, histology did not provide good criteria for evaluating the failure of vented endosteal blade implants. In four implants which failed, the most reliable signs of failure were increased mobility and/or sulcus depth around the neck of the abutments. Radiographic evaluation of implants provided the best means of determining bone resorption. Bone resorption was apparent 3 to 6 months after implantation, did not appear to be progressive, and did not indicate implant failure or impending implant failure in those animals in which it occurred. Radiolucent areas observed in 29 of the specimens contained connective tissue, marrow spaces, thin bone trabeculae, and nonpathologic tissues. Although in some of the dogs stress on implants did not cause failure, there is a need for further experimentation involving vented endosteal blades subjected to occlusal loading.     

Histomorphometric and densitometric evaluation of the effects of platelet-rich plasma on the remodeling of beta-tricalcium phosphate in beagle dogs

Countless possibilities are available in maxillofacial surgery for the filling of bone defects. The best bone substitute known at present is osteogenic autogenous bone, but its use is accompanied by numerous disadvantages. The question has arisen of whether results attained with osteoconductive bone substitutes approach those achieved by the transplantation of autogenous bone. The aims of the investigation were to measure the effects in animal experiments of the growth factors to be found in the platelets on the rate of remodeling of beta-tricalcium phosphate, and on the quality of the new bone formed. Defects formed in the mandibles of 10 Beagle dogs were filled with beta-tricalcium phosphate or with a mixture of beta-tricalcium phosphate and platelet-rich plasma obtained from autogenous blood. The quality of the hard tissue formed and the effect of the platelet-rich plasma were examined by statistical analysis of the densitometric results obtained after 6 weeks and the histological and histomorphometric results obtained after 12 weeks. The densitometric study revealed that the bone formation was significantly more effective when platelet-rich plasma was used; at this stage, histomorphometric evaluation did not indicate a significant difference. After 12 weeks, however, the histomorphometric study demonstrated a significant difference in favor of the bone substitute used together with platelet-rich plasma. The results strongly suggest that use of the platelet-rich plasma suspension accelerates the remodeling of beta-tricalcium phosphate and leads to the formation of hard tissue with a quality similar to that of the autogenous bone.     

The predominant cultivable dental plaque flora of beagle dogs with gingivitis

The predominant dental plaque flora of 15 female beagle dogs (1,3 and 6 year old) with naturally developed gingivitis was studied using a continuous anaerobic culturing technique. Supra- and subgingival plaque samples from the buccal aspect of the upper third premolar were cultured on various growth media and the organisms were partially characterized. The flora in all dogs was composed mostly of anaerobic Gram negative organisms. B. asaccharolyticus (B. melaninogenicus ss. asaccharolyticus) was found in both types of plaques in all animals and decomposed hydrogen peroxide suggesting catalase activity. F. nucleatum was found in higher proportions in the subgingival plaque as compared to B. asaccharolyticus and actinomycetes. Spirochetes were found in 10 of 15 supra- and in 1 of 15 subgingival specimens. S. mutans, S. mitior, S. salivarius, Veillonella, Selenomonas or vibrios could not be detected in any of the plaque samples. A combined data analysis showed, that the total viable CFU and the proportions of Gram positive organisms were significantly higher in the supra- than the subgingival plaque. Although the proportions of Gram negative bacteria were higher in subgingival plaque, the differences between the two types of plaques excluding F. nucleatum were not significant.     

The predominant cultivable dental plaque flora of beagle dogs with periodontitis

Abstract The predominant cultivable dental plaque flora was studied in 10 adult female beagle dogs with advanced periodontitis. Supragingival and subgingival plaque from a maxillary third premolar (P³) was removed and cultured anaerobically on various growth media and all colonies were subcultured and partially characterized. Histopathological specimens of the plaque sampling sites showed significant loss of connective tissue attachment. Spirochetes were found in ail samples. Anaerobic gram-negative organisms were predominant in both types of plaque accounting for about 55 % of the cultivable organisms in the supragingival plaque and almost 75% in the subgingival plaque. Bacteroides asaccharolyticus was the most prominant organism in the supragingival plaque, whereas Fusobacterium nucleatum predominated in the subgingival flora. Streptococcal and actinomycotic species were common in the supragingival plaque, but their proportions, especially those of the actmomycetes, were decreased in the subgingival flora. In many respects the bacterial profile associated with disease resembled that reported in human periodontal disease.