PURPOSE: To evaluate the biomechanical behavior of different types of PEEK as implant materials for mandibular implant-retained overdentures.

MATERIALS & METHODS: Virtual models of mandibular overdentures retained by two interforaminal implants were simulated. In each model, one implant material was assumed resulting in four models; titanium, carbon-reinforced PEEK, ceramic-filled PEEK and unfilled PEEK models. Unilateral vertical and oblique loads were applied separately. Von-Mises stresses and maximum equivalent strain values were computed.

RESULTS: All PEEK implant models induced higher stresses in the cervical portion of peri-implant bone compared to the titanium model. A more homogenous stress distribution pattern along the whole length of the titanium implants was observed compared to PEEK implants. The highest amount of strain values was recorded in the unfilled PEEK implants.

CONCLUSIONS: Titanium remains to be the most optimum material for dental implants. Unfilled and ceramic filled PEEK might not be recommended as a dental implant material due to the high stresses generated within the implant bodies and cervical part of peri-implant bone under oblique load which might contribute to an increased probability of implant body fracture and marginal bone loss.

BACKGROUND: Multiple myeloma (MM) is a hematological bone marrow malignancy that can be treated but is usually fatal. Medication resistance is the major cause of relapses due to cancer stem cells (CSCs). As a result, this study aimed to identify multiple myeloma cancer stem cells (MMCSCs) in the bone marrow of twelve MM patients with pathological complete response (pCR) after chemotherapy and to investigate the potential effect of Curcumin/Piperine (C/P) extract as an anti-MMCSCs treatment in twenty newly diagnosed patients.

METHODS: This study included twenty bone marrow (BM) samples from newly diagnosed MM patients and twelve BM samples from pCR patients after a year of treatment. The MTT test was performed to assess the treatment's effective dosage. A flow cytometer was used to identify MMCSCs, cell cycle profile, extract's apoptotic activity, and proliferation marker in the selected samples. Also,  a colony formation test and stemness protein were investigated.

RESULTS: In newly diagnosed MM patients, the C/P extract suppressed MMCSCs by 64.71% for CD138-/CD19- and 38.31% for CD38++. In MM patients' samples obtained after one year of treatment, the MMCSCs inhibition percentage reached 44.71% (P < 0.008) for CD138-/CD19- and 36.94% (P < 0.221) for CD38++. According to cell cycle analyses, the number of cells treated with C/P extract was significantly reduced in the S and G0/G1 phases (87.38%: 35.15%, and 4.83%: 2.17% respectively), with a rapid increase in the G2/M phases (1.1%: 2.2%.). MMCSCs apoptosis was identified using a flow cytometer and Annexin-V. Multiple myeloma stem cell (MMCSC) proliferation was inhibited. Clonogenicity was suppressed by 60%, and stemness protein expression was reduced by 70%.

CONCLUSION: MMCSCs in the bone marrow of MM-pCR patients can be utilized as a prognostic tool to predict recurrent multiple myeloma incidence. Also, the therapeutic potential of C/P extract as a prospective anti-MM drug targeting MMCSCs.

Large volume atmospheric pressure glow discharge plasma was developed and investigated to enhance the biological activities of M. oleifera seeds. The generated plasma was characterized optically, electrically, and spectroscopically. The large volume plasma size can reach 40 mm gape and 150 mm diameter. One hundred ns magnetic pulse compression high voltage system was used to generate the plasma where the current increases with increasing applied voltage at a constant frequency and discharge gap while the current decreases with increasing discharge gap at constant voltage and frequency. The plasma homogeneity was enhanced with higher applied voltage and frequency. Nitrogen second positive system bands dominated the plasma emission spectra, and its intensity increased with increasing applied voltage and frequency. There was a steady reduction in the total count of emerged seedborne fungi on the application of cold plasma with complete elimination of fungi at ≥ 13 A. The low doses of cold plasma (3.9 and 5.8 A) induced an increase in the seed germination, a significant increase in chlorophyll content (chl a and chl b ) and antioxidant activities of the seedlings emerged from soaked or wet seeds rather than dry seeds. There was a steady reduction in the total count of emerged fungi reaching complete decontamination of seedborne fungi at higher plasma doses (≥ 13 A). The plasma was harmful when applied at higher doses (≥ 13 A) and more harmful to the wet seeds compared to the dry ones, where the chlorophyll a content of the seedling developed from 1% H 2 O 2 soaked seeds.