Poly ether keton keton polymer deposition on laser surface structured commercial pure titanium using magnetron sputtering / Deposição de polímero de poliéter cetona cetona em titânio comercial puro com superfície estruturada a laser usando pulverização catódica por magnetro

Objective: This study aimed to evaluate the effect of coating titanium (Ti) dental implant with polyether ketone ketone (PEKK) polymer using magnetron sputtering on osseointegration, trying to overcome some of the problems associated with Ti alloys. Material and Methods: Implants were prepared from grade (II) commercially pure titanium (CP Ti), then laser was used to induce roughness on the surface of Ti. PEKK was deposited on the surface of Ti implants by radiofrequency (RF) magnetron sputtering technique. The implants were divided in to three groups: without coating (Ls), with PEKK coating using argon (Ar) as sputtering gas (Ls-PEKK-Ar), and with PEKK coating using nitrogen (N) as sputtering gas (Ls-PEKK-N). All the implants were implanted in the femoral bones of rabbits. After three different healing periods (2, 6, and 12 weeks) the rabbits were sacrificed for a mechanical examination (removal torque) and for histological examination. Results: The results revealed a significant increase in the removal torque mean values when using PEKK coating on Ti implants, with the highest value recorded by Ls-PEKK-N group. Histologically, the study demonstrated the progression of osteogenesis during all the research periods. It was observed that the Ls-PEKK-N group had the highest percentage of new bone formation in all healing periods. Conclusion: The use of PEKK as coating material on the surface of Ti implants by RF- magnetron sputtering results in an increase in the torque required to remove implants and enhance bony tissue formation around the implants especially when using nitrogen as a sputtering gas (AU)

Objetivo: Este estudo teve como objetivo avaliar o efeito do revestimento de implante dentário de titânio (Ti) com polímero de poliéter cetona cetona (PEKK) usando pulverização catódica por magnetron na osseointegração, tentando superar alguns dos problemas associados às ligas de Ti. Material e Métodos: Os implantes foram preparados a partir de titânio comercialmente puro grau (II) (CP Ti), em seguida o laser foi utilizado para induzir rugosidade na superfície do Ti. PEKK foi depositado na superfície de implantes de Ti pela técnica de pulverização catódica por radiofrequência (RF). Os implantes foram divididos em três grupos: sem revestimento (Ls), com revestimento de PEKK utilizando argônio (Ar) como gás de pulverização catódica (Ls-PEKK-Ar) e com revestimento de PEKK utilizando nitrogênio (N) como gás de pulverização catódica (Ls-PEKK -N). Todos os implantes foram implantados em ossos femorais de coelhos. Após três períodos de cicatrização diferentes (2, 6 e 12 semanas), os coelhos foram sacrificados para exame mecânico (torque de remoção) e exame histológico. Resultados: Os resultados revelaram um aumento significativo nos valores médios do torque de remoção quando se utilizou o revestimento de PEKK em implantes de Ti, sendo o maior valor registrado pelo grupo Ls-PEKK-N. Histologicamente, o estudo demonstrou a progressão da osteogênese durante todos os períodos da pesquisa Observou-se que o grupo Ls-PEKK-N apresentou maior percentual de neoformação óssea em todos os períodos de cicatrização. Conclusão: O uso de PEKK como material de revestimento na superfície de implantes de Ti por pulverização catódica RF-magnetron resulta em um aumento no torque necessário para remover os implantes e melhorar a formação de tecido ósseo ao redor dos implantes, especialmente quando se utiliza nitrogênio como gás de pulverização catódica(AU)

Investigating Tensile Bonding and Other Properties of Yttrium Oxide Nanoparticles Impregnated Heat-Cured Soft-Denture Lining Composite In Vitro.

Aims: This study was conducted to assess the effect of the addition of yttrium oxide (Y2O3) nanoparticles on the tensile bond strength, tear strength, shore A hardness, and surface roughness of soft-denture lining material. Materials and Methods: Y2O3 NPs with 1.5 and 2 wt.% were added into acrylic-based heat-cured soft-denture liner. A total of 120 specimens were prepared and divided into four groups according to the test to be performed (tensile bond strength, tear strength, surface hardness, and surface roughness). Results: There was a highly significant increase in tensile bond strength between the soft liner and the acrylic denture base, tear strength, and hardness at both concentrations as compared to the control group, whereas there was a nonsignificant difference between 1.5wt% of Y2O3 nanoparticles and the control group, and between 1.5wt% and 2wt% of Y2O3 nanoparticles. But there was a significant difference between 2wt% of Y2O3 nanoparticles and the control group. Conclusion: The Y2O3 nanoparticles impregnated in soft-lining materials increased the mechanical properties of both tensile bonding strength and tear strength. Also, there was a significant increase in hardness but there was no change in surface roughness of acrylic-based denture soft-lining materials.

Effects of Long Durations of RF-Magnetron Sputtering Deposition of Hydroxyapatite on Titanium Dental Implants.

OBJECTIVES: Dental implant is a revolution in dentistry; some shortages are still a focus of research. This study use long duration of radiofrequency (RF)-magnetron sputtering to coat titanium (Ti) implant with hydroxyapatite (HA) to obtain a uniform, strongly adhered in a few micrometers in thickness. MATERIALS AND METHODS: Two types of substrates, discs and root form cylinders were prepared using a grade 1 commercially pure (CP) Ti rod. A RF-magnetron sputtering device was used to coat specimens with HA. Magnetron sputtering was set at 150 W for 22 hours at 100°C under continuous argon gas flow and substrate rotation at 10 rpm. Coat properties were evaluated via field emission scanning electron microscopy (FESEM), scanning electron microscopy-energy dispersive X-ray (EDX) analysis, atomic force microscopy, and Vickers hardness (VH). Student's t-test was used. RESULTS: All FESEM images showed a homogeneous, continuous, and crack-free HA coat with a rough surface. EDX analysis revealed inclusion of HA particles within the substrate surface in a calcium (Ca)/phosphorus (P) ratio (16.58/11.31) close to that of HA. Elemental and EDX analyses showed Ca, Ti, P, and oxygen within Ti. The FESEM views at a cross-section of the substrate showed an average of 7 µm coat thickness. Moreover, these images revealed a dense, compact, and uniform continuous adhesion between the coat layer and the substrate. Roughness result indicated highly significant difference between uncoated Ti and HA coat (p-value < 0.05). A significant improvement in the VH value was observed when coat hardness was compared with the Ti substrate hardness (p-value < 0.05). CONCLUSION: Prolonged magnetron sputtering successfully coat Ti dental implants with HA in micrometers thickness which is well adhered essentially in excellent osseointegration.

Treatment of metastatic carcinoid tumours, phaeochromocytoma, paraganglioma and medullary carcinoma of the thyroid with (131)I-meta-iodobenzylguanidine [(131)I-mIBG].

OBJECTIVE: Meta-iodo-benzyl-guanidine labelled with 131-iodine [(131)I-mIBG] has been used extensively for imaging tumours originating from the neural crest but experience with its therapeutic use is limited, particularly for non-catecholamine secreting tumours. In order to assess the therapeutic response and potential adverse effects of the therapeutic administration of (131)I-mIBG, we have reviewed all patients who had received this form of treatment in our department. DESIGN: Retrospective analysis of the case notes of patients with neuroendocrine tumours who received treatment with (131)I-mIBG and were followed-up according to a defined protocol in a given time frame. PATIENTS: Thirty-seven patients (18 with metastatic carcinoid tumours, 8 metastatic phaeochromocytoma, 7 metastatic paraganglioma and 4 metastatic medullary carcinoma of the thyroid) treated with (131)I-mIBG over a 15-year period were included in this analysis. MEASUREMENTS: The symptomatic, hormonal and tumoural responses before and after (131)I-mIBG therapy over a median follow-up duration of 32 months (range 5-180 months) were recorded. Of the 37 patients (22 males; median age 51 years, range 18-81 years), 15 were treated with (131)I-mIBG alone whereas the other 22 received additional therapy. RESULTS: A total of 116 therapeutic (131)I-mIBG doses were administered [mean cumulative dose 592 mCi (21.9 GBq); range 200-1592 mCi (7.4-58.9 GBq)]. None of the patients showed a complete tumour response. However, 82% of patients treated with (131)I-mIBG alone and 84% who received additional therapy showed stable disease over the period of follow-up. Overall survival during the period of the study was 71%. The overall 5-year survival rate was 85% (95% confidence interval, 72-99%) for all patients and 78% (95% confidence interval, 55-100%) for the carcinoid group alone, according to Kaplan-Meier analysis. Symptomatic control was achieved in all the patients treated with (131)I-mIBG alone, and in 72% of those receiving additional therapy. Hormonal control was noted in 50% and 57% of patients, respectively. (131)I-mIBG therapy was safe and well tolerated. Serious side-effects necessitating the termination of (131)I-mIBG therapy were seen in only 2 of our patients. CONCLUSIONS: (131)I-mIBG therapy produces symptomatic and hormonal improvement and moderate tumour regression/stabilization in patients with metastatic neuroendocrine tumours with minimal adverse effects. It may be a valuable alternative or additional therapeutic option to the currently available conventional treatment modalities.