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The purpose of this systematic review was to summarize scientific evidence that evaluates in vitro fracture and fatigue strength of occlusal veneers in different thicknesses, CAD/CAM materials, and under different aging methodologies.

An electronic search of 3 English databases (The National Library of Medicine (MEDLINE/PubMed), ScienceDirect, and EBSCOhost) was conducted. Laboratory studies published between September 2009 and October 2019 that evaluated fracture or fatigue strength of CAD/CAM occlusal veneers and used human teeth were selected. The included studies were individually evaluated for the risk of bias following a predetermined criterion. The outcomes assessed included the types of the restorative material, the thickness of the veneers, and aging methods.

A total of 12 studies fulfilled the inclusion criteria. Most of the included studies (86%) evaluated the fracture strength of occlusal veneers. Two studies evaluated fatigue resistance. There was a significant relationship between the choice of materials and fracture strength. Polymeric materials performed better in fatigue testing in comparison to ceramics. Netarsudil Lithium silicate-based glass ceramics showed more favorable outcomes in a thickness of 0.7-1.0mm. Fracture resistance values in all the included studies exceeded maximum bite forces in the posterior region.

The outcomes of this systematic review suggest that occlusal veneers can withstand bite forces in the posterior region, whereas the measurement of thickness should be standardized in order to have a fair comparison. Further research needs to be conducted to evaluate the longevity of this type of restorations clinically.
The outcomes of this systematic review suggest that occlusal veneers can withstand bite forces in the posterior region, whereas the measurement of thickness should be standardized in order to have a fair comparison. Further research needs to be conducted to evaluate the longevity of this type of restorations clinically.
The purpose of this study was to study the effects on Young's modulus and conversion degree of variations in polymerization conditions during the 3-point bending test of composite samples in accordance with the ISO 4049 standard.

Three nanocomposites were used in the 3-point bending test based on the conditions described in the ISO 4049 standard. Samples of 2mm×2mm x 25mm were fabricated and tested with a different number of irradiation points and irradiation time. Conversion degree of the samples were also measured by micro-Raman spectroscopy and correlated with the Young's modulus values obtained for each one.

The variations in curing protocol during specimen's realization influenced the Young's modulus and degree of conversion of all composites. These two properties correlated well. The ISO 4049 standard defines the conditions for performing the properties tests of composites to allow reproducibility and comparison of different studies. Concerning the 3-point bending test, even a minimal change in the state causes differences in the results obtained. The standard should thus clarify the tools that can be used when producing samples in order to minimize discrepancies.

The influence of the parameters surrounding the design of the samples should be controlled and defined so as not to include bias in the studies carried out. This will allow literature studies to be compared with more accuracy.
The influence of the parameters surrounding the design of the samples should be controlled and defined so as not to include bias in the studies carried out. This will allow literature studies to be compared with more accuracy.The force experienced while inserting an 18-gauge Tuohy needle into the epidural space or dura is one of only two feedback components perceived by an anaesthesiologist to deduce the needle tip position in a patient's spine. To the best of the authors knowledge, no x-ray validated measurements of these forces are currently available to the public. A needle insertion force recording during an automated insertion of an 18-gauge Tuohy needle into human vertebral segments of four female donors was conducted. During the measurements, x-ray images were recorded simultaneously. The force peaks due to the penetration of the ligamentum supraspinale and ligamentum flavum were measured and compared to the measurements of an artificial patient phantom for a hybrid patient simulator. Based on these force peaks and the slope of the ligamentum interspinale, a mathematical model was developed. The model parameters were used to compare human specimens and artificial patient phantom haptics. The force peaks for the ligamenta supraspinale and flavum were 7.55 ± 3.63 N and 15.18 ± 5.71 N, respectively. No significant differences were found between the patient phantom and the human specimens for the force peaks and four of six physical model parameters. The patient phantom mimics the same resistive force against the insertion of an 18-gauge Tuohy needle. However, there was a highly significant (p less then 0.001, effsize = 0.949 and p less then 0.001, effsize = 0.896) statistical difference observed in the insertion depth where the force peaks of the ligamenta supraspinale and flavum were detected between the measurements on the human specimens and the patient phantom. Within this work, biomechanical evidence was identified for the needle insertion force into human specimens. The comparison of the measured values of the human vertebral segments and the artificial patient phantom showed promising results.
During revision total knee arthroplasty (rTKA), proximal tibial bone loss is frequently encountered and can result in a less-stable bone-implant fixation. A 3D printed titanium revision augment that conforms to the irregular shape of the proximal tibia was recently developed. The purpose of this study was to evaluate the fixation stability of rTKA with this augment in comparison to conventional cemented rTKA.

Primary total knee arthroplasty (pTKA) surgery was performed on 11 pairs of thawed fresh-frozen cadaveric tibias (22 tibias). Fixation stability testing was conducted using a three-stage eccentric loading protocol. Bone-implant micromotion was measured using a high-resolution optical system. The pTKA were removed. Revision TKA was performed using a 3D printed titanium augment or a standard fully cemented stem. The three-stage eccentric loading protocol was repeated and micromotion was measured for the revision implants.

After rTKA, the mean vertical micromotion was 28.1μm±(SD) 20.3μm in the control group and 17.
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