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The major role of integrins is to mediate cell adhesion but some of them are involved in the osteoblasts-titanium (Ti) interactions. In this study, we investigated the participation of integrins in osteoblast differentiation induced by Ti with nanotopography (Ti-Nano) and with microtopography (Ti-Micro). By using a PCR array, we observed that, compared with Ti-Micro, Ti-Nano upregulated the expression of five integrins in mesenchymal stem cells, including integrin β3, which increases osteoblast differentiation. Silencing integrin β3, using CRISPR-Cas9, in MC3T3-E1 cells significantly reduced the osteoblast differentiation induced by Ti-Nano in contrast to the effect on T-Micro. Concomitantly, integrin β3 silencing downregulated the expression of integrin αv, the parent chain that combines with other integrins and several components of the Wnt/β-catenin and BMP/Smad signaling pathways, all involved in osteoblast differentiation, only in cells cultured on Ti-Nano. Taken together, our results showed the key role of integrin β3 in the osteogenic potential of Ti-Nano but not of Ti-Micro. Additionally, we propose a novel mechanism to explain the higher osteoblast differentiation induced by Ti-Nano that involves an intricate regulatory network triggered by integrin β3 upregulation, which activates the Wnt and BMP signal transductions. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1303-1313, 2019.

AIM To report the main differences seen by direct visual inspection between original and counterfeit Reciproc instruments, together with an evaluation of instrument bending resistance, cyclic fatigue, surface finish, Vickers microhardness and chemical composition. METHODOLOGY The visual aspects of original Reciproc R25 (VDW, Munich, Germany) and counterfeit Reciproc R25 instruments (claimed to be original, supposedly with dimensions similar to those of Reciproc R25 files, bought at www.mercadolivre.com.br) were evaluated under direct observation, stereomicroscopy and scanning electron microscope. The flexibility of original and counterfeit Reciproc R25 was determined via 45° bending tests according to the ISO 3630-1 specification. Instruments were also subjected to cyclic fatigue resistance, measuring the time to fracture in an artificial stainless steel canal with a 60° angle and 5-mm radius of curvature. The fracture surfaces of all fragments were examined under a scanning electron microscope. Roughness of the instruments was quantified using a profilometer, and the microhardness test was carried out using a Vickers hardness tester. Energy-dispersive X-ray microanalysis (EDX) was also carried out. Results were analysed statistically using the Student's t-test at a significance level of P

Over the last decades, much research has been done to improve the surface quality of dental implants, but there was no change in the materials used to manufacture the implants. The purpose of the present work is to compare the compressive strength and fatigue failure of dental implants made with a new material, nanocrystalline Ti grade 4 fabricated by Equal Channel Angular Pressing (ECAP) (Ti Hard) with a traditional material, microcrystalline Ti grade 4 (Ti G4). Machined screw-shaped implants with three different designs (Easy, Torq and Flash) made with the two materials were subjected to static and dynamic compressive loads. Implants made with Ti Hard showed higher static compressive strength (Easy: 889.9 ± 79.4 N, Flash: 588.9 ± 74.7 N, Torq: 498.3 ± 54.6 N) than implants made with TiG4 (Easy: 776.4 ± 74.5 N, Flash: 308.8 ± 15.2 N, Torq: 410.3 ± 25.2 N) and higher fatigue strength for 5 106 cycles (Easy: 400 N, Flash: 280 N, Torq: 260 N) than implants made with TiG4 (Easy: 300 N, Flash: 200 N, Torq: 200 N). The higher fatigue strength of nanocrystalline Ti G4 is attributed to a delay in crack initiation.

Background Cell interactions, adherence, and osseointegration at the bone-implant interface can be directly influenced by the surface properties of the titanium implant. Purpose To characterize osseointegration of Neoss® implants with conventional (control group) and hydrophilic (test group) surface treatments. Materials and Methods Six Labrador dogs received Neoss implants with conventional and hydrophilic surfaces. The bone-implant interfaces were evaluated 1 and 4 weeks after implantation, and osseointegration was evaluated using histological, histomorphometric, fluorescence, and resonance frequency analyses. The surfaces were also subjected to topographic and hydrophilicity analyses. Results The topographic analyses revealed increased surface roughness in the test group compared with the control group (surface area roughness 0.42 and 0.78 μm, respectively, for control and test group surfaces; p ≤ .05). The wettability values were higher in the test group (contact angles 67.2° and 27.2° for the control and test group surfaces, respectively; p ≤ .05). Implants in the test group also exhibited better stability, more bone-implant contact, and increased bone area compared with implants in the control group. Conclusion Neoss implants in the test group improved bone formation in the early stages of osseointegration compared with implants in the control group.

The manufacturing of ceramics fixed dental prostheses (FDPs) is not the same as that of standardized samples and, therefore, the surface finishing are not necessarily the same in both cases. Standardized samples and FDPs were sintered, polished, hydrothermally aged in saliva, and submitted to mechanical tests. The results showed a difference in bending strength between machined (911.19 MPa) and polished FDPs (573.84 MPa). ANOVA statistical analysis did not show a difference in flexural strength between nondegraded (911.19 MPa) and degraded (871.94 MPa) FDPs. No differences were found in the bending strength and toughness of standardized samples and FDPs.

De-Deus G, Moreira EJL, Lopes HP, Elias CN. Extended cyclic fatigue life of F2 ProTaper instruments used in reciprocating movement. International Endodontic Journal. Aim To evaluate the cyclic fatigue fracture resistance of engine-driven F2 ProTaper instruments under reciprocating movement. Methodology A sample of 30 NiTi ProTaper F2 instruments was used. An artificial canal was made from a stainless steel tube, allowing the instruments to rotate freely. During mechanical testing, different movement kinematics and speeds were used, which resulted in three experimental groups (n = 10). The instruments from the first group (G1) were rotated at a nominal speed of 250 rpm until fracture, whilst the instruments from the second group (G2) were rotated at 400 rpm. In the third instrument group (G3), the files were driven under reciprocating movement. The time of fracture for each instrument was measured, and statistical analysis was performed using parametric methods. Results Reciprocating movement resulted in a significantly longer cyclic fatigue life (P < 0.05). Moreover, operating rpm was a significant factor affecting cyclic fatigue life (P < 0.05); instruments used at a rotational speed of 400 rpm (approximately 95 s) failed more rapidly than those used at 250 rpm (approximately 25 s). Conclusions Movement kinematics is amongst the factors determining the resistance of rotary NiTi instruments to cyclic fracture. Moreover, the reciprocating movement promoted an extended cyclic fatigue life of the F2 ProTaper instrument in comparison with conventional rotation.

Background: Primary implant stability has been used as an indicator for future osseointegration and whether an immediate/early loading protocol should be applied. Implant stability is the key to clinical success. Purpose: The aim of this work was to analyze the influence of the design and surface morphology on the primary stability of dental implants. The insertion torque and resonance frequency analysis (RFA) were the parameters used to measure the primary stability of the implants. Materials and Methods: Thirty implants, divided in six groups of five samples were placed in cylinder of high molecular weight polyethylene. The groups were different upon two designs (cylindrical and conic) and three implant surfaces finishing (machined, acid etched, and anodized). The insertion torque was quantified by a digital torque driver (Lutron Electronic Enterprise Co., Taipei, Taiwan) and the resonance frequency was measured by Osstell mentor™ (Integration Diagnostics AB, Goteborg, Sweden). The implant surface morphology was characterized by scanning electron microscopy, roughness measurement, and friction coefficient. Results: The machined implants showed smaller insertion torques than treated implant surfaces. There were no differences between the RFA measurements in all tested surfaces. Statistical analyses demonstrated no correlation between the dental implant insertion torque and primary stability measured by the RFA. The implants with treated surfaces showed greater roughness, a higher friction coefficient, and demanded a larger insertion torque than machined implants. The results of the surface roughness and friction coefficients are in accordance with the results of the insertion torque. The difference, across the insertion torque values, between conical and cylindrical implants, can be explained by the different contact surface area among the thread geometry of these implants. Conclusion: The maximum implant insertion torque depends on the implant geometry, thread form, and implant surface morphology. The placement of conical implants with treated surfaces required the highest insertion torque. There was no correlation between RFA and insertion torque implant.