Retrospective Evaluation of Crestal Bone Changes Around Implants With Reduced Abutment Diameter Placed Non‐Submerged and at Subcrestal Positions: The Effect of Bone Grafting at Implant Placement

Background: There is limited information regarding the effect of grafting of the osteotomy after subcrestal implant placement. The primary aim of this study is to retrospectively evaluate the effect of bone grafting of the defect between the bone crest and the coronal aspect of implants with reduced abutment diameter placed non‐submerged and at subcrestal positions. Methods: Records of 50 consecutive patients treated with subcrestally placed dental implants grafted with a xenograft (Group A) and 50 consecutive patients with subcrestally placed dental implants without any grafting material (Group B) were reviewed. For each implant, the radiographs after placement were compared to images from the last follow‐up visit and evaluated regarding the following: 1) degree of subcrestal positioning of the implant, 2) changes of marginal hard‐tissue height over time, and 3) whether marginal hard‐tissue could be detected on the implant platform at the follow‐up visit. Results: The mean marginal loss of hard tissues was 0.11 ± 0.30 mm for Group A and 0.08 ± 0.22 mm for Group B. Sixty‐nine percent of the implants in Group A and 77% of the implants in Group B demonstrated hard tissue on the implant platform. There were no statistically significant differences between the groups regarding marginal peri‐implant hard‐tissue loss. Conclusion: The present study fails to demonstrate that grafting of the remaining osseous wound defect between the bone crest and the coronal aspect of the implant has a positive effect on marginal peri‐implant hard‐tissue changes.     

Comparison of Fracture Toughness of All-Ceramic and Metal–Ceramic Cement Retained Implant Crowns: An In Vitro Study

To evaluate the fracture toughness of cement-retained implant-supported metal–ceramic molar crown with that of all-ceramic crowns, fabricated using IPS Empress 2 and yttria-stabilized zirconia copings. An dental implant and abutment was embedded in a clear polymethyl methacrylate model. A wax pattern reproducing the anatomy and dimension of a mandibular molar was made using inlay wax. Copings were made from the manufacturers guidelines for zirconia, metal ceramic and empress crown, in total of 21 copings, which were built for the crowns with metal layering ceramics specified by the manufacturers. The polymethylmethacrylate block-implant abutment complex was mounted on universal testing machine, and a static continuos vertical compressive load with a crosshead speed of 0.5 mm/min was applied. The breaking load and the peak load (in kilo Newtons) were recorded. The fractures for group I (zirconia–ceramic) and group II (metal–ceramic) occurred on the mesio-buccal aspect of the crowns involving the veneered ceramic layer while the catastrophic/bulk fracture was not observed. The mean value of breaking load for zirconia–ceramic, metal–ceramic and IPS-empress 2 was 3.4335, 3.071 and 1.0673 kN respectively. The mean value of peak load for zirconia–ceramic, metal–ceramic and IPS-empress 2 was 4.7365, 3.2757 and 1.566 kN respectively. It can be concluded that the zirconia–ceramic crown with the fracture toughness of 4.7365 ± 2.2676 kN has sufficient strength to allow clinical testing of these crowns as an alternative for metal–ceramic crowns (3.2757 ± 0.4681 kN).     

Preparation and first biological evaluation of novel Re-188/Tc-99m peptide conjugates with substance-P

IntroductionNew ¹⁸⁸Re and ^99mTc peptide conjugates with substance- P (SP) were prepared and biologically evaluated. The radiopharmaceuticals have been labelled with the [M≡N]²⁺ (M=^99mTc, ¹⁸⁸Re) core using a combination of π-donor tridentate and π-acceptor monodentate ancillary ligands.MethodsThe new radiopharmaceuticals have been prepared through a two-step reaction by simultaneous addition of the tridentate and monodentate ligands to a vial containing a preformed [M≡N]²⁺ core. The tridentate ligand was formed by linking two cysteine residues to the terminal arginine of the undecapeptide SP, whereas the monodentate ligand was a tertiary phosphine. The preparation of the corresponding Re-188 derivative required developing a more complex chemical procedure to obtain the [Re≡N]²⁺ core in satisfactory yields. Characterization of the resulting products was obtained by chromatographic methods. Biological evaluation was performed for both Tc-99m and Re-188 derivatives by in-vitro studies on isolated cells expressing NK1-receptors. In-vivo imaging in mice was carried out using a small-animal YAP(S)PET tomograph.ConclusionNew Tc-99m and Re-188 peptide radiopharmaceuticals with SP have been prepared in high-yield and with high-specific activity. Both Tc-99m and Re-188 peptide radioconjugates exhibit high affinity for NK1 receptors, thus giving further evidence to the empirical rule that structurally related Tc-99m and Re-188 radiopharmaceuticals exhibit identical biological properties.     

医源性十二指肠穿孔钛夹封闭治疗的护理

目的 探讨金属钛夹在内镜下封闭治疗医源性十二指肠急性穿孔中的应用及护理配合.方法 收集2例经自然腔道的内镜手术导致十二指肠急性穿孔者,进行内镜下钛夹封闭治疗.结果 2例患者均在内镜直视下予多枚金属钛夹封闭创面,术后予心电监护、禁食、胃肠减压、抗生素预防感染以及营养支持治疗,术后无出血、再穿孔、腹腔脓肿等并发症发生,均恢复良好.结论 早期内镜下钛夹封闭是治疗内镜诊治出现的医源性穿孔的有效方法,充分的术前准备、熟练的术中医护配合、精心的术后护理是成功治疗的重要保证.     

Evaluation of titanium release from titanium alloy implants in patients with spinal instrumentation

ObjectiveThis study was performed to investigate the baseline serum titanium levels in patients with short-segment titanium alloy posterior instrumentation and to assess patient-, implant-, and surgery-related factors that might affect the serum titanium level.MethodTwo groups of patients were included in the study. The study group comprised 39 patients who had undergone short-segment posterior instrumentation from January 2013 to June 2016. The control group comprised 11 randomly selected patients who presented to the outpatient clinic with no history of orthopedic surgery. The serum titanium levels and inter-group differences were analyzed.ResultsThe mean serum titanium level was significantly higher in the study group than in the control group. No significant difference was observed between patients with different etiologies, implants used for fusion, numbers of instrumented segments, or postoperative durations.ConclusionThe serum titanium levels of patients with posterior lumbar spinal instrumentation are significantly higher than those of the normal population even after achievement of solid fusion. These levels are not affected by the use of transverse connectors, the use of cages, the operated segments, or the duration of implants.     

微弧氧化技术与钛合金表面成骨细胞增殖及骨向分化能力

文题释义：微弧氧化技术：是金属材料表面处理的一种技术，将金属材料(如，镁、铝、钛等)置于特定电解液中，通过弧光放电过程中瞬时的高温和高压条件产生结合于金属表面的陶瓷膜层，该种方法制备的涂层材料具有高硬度、耐磨的特点。  种植体：是针对于人体自身牙齿缺失而植入上下颌骨内的人工牙根。性能优良的种植体需要同时具备高强度、耐降解、生物相容性好的特性。目前复合材料类如金属表面添加陶瓷涂层材料，具有上述多种材料特性而被临床选择。 背景：采用普通电化学法可在钛及其合金表面制备纳米级羟基磷灰石涂层，但该涂层吸收降解缓慢，需要8-12周的时间。而微弧氧化可在复杂表面形成均匀薄膜，有利于细胞黏附和骨组织长入。 目的：探索微弧氧化羟基磷灰石涂层钛合金对成骨细胞增殖及骨向分化能力的影响。 方法：采用电化学法与微弧氧化法分别制备羟基磷灰石涂层钛合金材料，检测两种材料表面的接触角。将成骨细胞系hFOB1.19接种于两组羟基磷灰石涂层钛合金材料表面，培养48 h时，采用扫描电镜观察细胞在材料上的形态变化；培养1，12，24，48，72 h时，采用MTT法检测细胞增殖；培养1，3，5 d时，比较两组材料表面细胞计数与碱性磷酸活性；培养第5天，采用Western Blotting检测细胞内骨形态发生蛋白2和骨形态发生蛋白4表达。 结果与结论：①微弧氧化组材料表面的接触角小于电化学组[(66.5±2.2)°，(52.8±2.1)°，P=0.001 5)]；②扫描电镜显示，电化学组成骨细胞形态不规则，胞体皱缩不饱满，与材料贴合较差；微弧氧化组细胞充分伸展，形态扁平，与材料贴合紧密；③微弧氧化组12-72 h的细胞增殖快于电化学组(P < 0.05)，培养3，5 d的细胞计数多于电化学组(P < 0.05)；④微弧氧化组培养1，3，5 d的细胞碱性磷酸酶活性高于电化学组(P < 0.05)；⑤微弧氧化组骨形态发生蛋白2和骨形态发生蛋白4表达均高于电化学组(P < 0.05)；⑥结果表明，微弧氧化羟基磷灰石涂层钛合金材料可促进成骨细胞的增殖及骨向分化能力。 ORCID: 0000-0003-2787-4667(王艳玲) 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程