Similar Fracture Research Articles

Recycled Aggregates in Roller-Compacted Concrete

With increasing demand for more sustainable pavement options, roller-compacted concrete (RCC) is attractive because of its lower cement contents, construction expediency, and early opening to traffic. Addition of recycled aggregates to RCC can further economize this pavement type. The objective of this study was to determine the effects of the following recycled aggregates on RCC mixture design and hardened properties: recycled concrete aggregate (RCA), electric arc furnace (EAF) slag aggregates, reclaimed asphalt pavement (RAP), and steel furnace slag fractionated reclaimed asphalt pavement (SFSFRAP). For each mixture, compressive, split tensile, and flexural strengths and fracture properties were tested at multiple ages. The strength of the RCC containing recycled aggregates was similar to or lower than the RCC with virgin except for the RCC mixture with EAF, which produced statistically greater compressive strength. As expected, RAP and SFSFRAP resulted in lower compressive strengths compared to the virgin aggregate RCC. All RCC mixes with recycled aggregates had statistically lower flexural strength to RCC with virgin aggregates except the EAF aggregates. Disk compact tension fracture testing demonstrated that all recycled aggregate mixes had similar or greater values of critical stress intensity factor and total fracture energy relative to the virgin RCC. Based on past slab testing of concrete with recycled aggregates that had similar or greater fracture parameters relative to virgin aggregate concrete, slab flexural capacities are anticipated to be similar for RCC with and without recycled aggregates despite the lower strength properties for RCC containing recycled aggregates except the EAF aggregates.

Comparison of mode II delamination behaviours in multidirectional and unidirectional composite laminates

Multidirectional (MD) composite laminates are extensively employed in structural applications owing to their superior mechanical characteristics. Nevertheless, the evaluation of the fracture toughness of composite laminates primarily relies on tests using unidirectional (UD) specimens. This study evaluates the reliability of characterizing mode II delamination behaviour in MD laminates by using UD specimens. The quantification of delamination area through Digital Image Correlation (DIC) analysis is integrated with a physical Energy Release Rate (ERR) method to ascertain the fracture resistance, which is compared with the ERR derived via a modified J-integral method and the standardized compliance methods. Fractographic analysis reveals similar fracture mechanisms in specimens with identical interfaces. The physical ERR increases notably due to large-scale fibre bridging induced by fibre nesting at 0∘//0∘ interfaces. Conversely, in 0∘//90∘ interfaces, large-area matrix cracking enhances the intrinsic fracture resistance, excluding the extrinsic toughening provided by fibre bridging.

A surrogate FRAX model for Nepal

SummaryA surrogate FRAX® model for Nepal has been constructed using age- and sex-specific hip fracture rates for Indians living in Singapore and age- and sex-specific mortality rates from Nepal.IntroductionFRAX models are frequently requested for countries with little or no data on the incidence of hip fractures. In such circumstances, the development of a surrogate FRAX model is recommended based on country-specific mortality data but using fracture data from a country, usually within the region, where fracture rates are considered to be representative of the index country.ObjectiveThis report describes the development and characteristics of a surrogate FRAX model for Nepal.MethodsThe FRAX model used the ethnic-specific incidence of hip fracture in the Indian community of Singapore, combined with the death risk for Nepal in 2015–2019. The number of hip fractures in 2015 and 2050 was estimated based on the United Nations’ predicted changes in population demography.ResultsThe surrogate model gave similar hip fracture probabilities to estimates from Sri Lanka, India and Pakistan but lower 10-year fracture probabilities for men and women at older ages compared to the model for Singapore, reflecting a higher mortality risk in Nepal compared with Singapore. There were very close correlations in fracture probabilities between the Nepalese and the Singapore models (r> 0.995) so that the use of the Nepalese model had little impact on the rank order of risk, i.e. a person at the xth percentile of risk with one model will be at the xth percentile of risk with the other. It was estimated that 6897 hip fractures arose in 2015 in individuals aged 50 years and older in Nepal, with a predicted 3-fold increase expected by 2050, when 23,409 hip fractures are expected nationally.ConclusionThe surrogate FRAX model for Nepal provides an opportunity to determine fracture probability within the Nepalese population and help guide decisions about treatment.

Fracture Toughness of Short Fibre-Reinforced Composites-In Vitro Study.

The development of dental materials needs to be supported with sound evidence. This in vitro study aimed to measure the fracture toughness of a short fibre-reinforced composite (sFRC), at differing thicknesses. In this study, 2 mm, 3 mm and 4 mm depths of sFRC were prepared. Using ISO4049, each preparation was tested to failure. A total of 60 samples were tested: 10 samples for each combination of sFRC and depth. Fractured samples were viewed, and outcomes were analysed. EXF showed greater toughness than EXP, with a mean of 2.49 (95%CI: 2.25, 2.73) MPa.m1/2 compared to a mean of 2.13 (95%CI: 1.95, 2.31) MPa.m1/2, (F(1,54) = 21.28; p < 0.001). This difference was particularly pronounced at 2 mm depths where the mean (95%CI) values were 2.72 (2.49, 2.95) for EXF and 1.90 (1.78, 2.02) for EXP (Interaction F(2,54) = 7.93; p < 0.001). Both materials performed similarly at the depths of 3 mm and 4 mm. The results for both materials were within the accepted fracture toughness values of dentine of 1.79-3.08 MPa.m1/2. Analysis showed crack deflection and bridging fibre behaviour. The optimal thickness at the cavity base for EXF was 2 mm and for EXP 4 mm. Crack deflection and bridging behaviour indicated that restorations incorporating sFRCs are not prone to catastrophic failure and confirmed that sFRCs have similar fracture toughness to dentine. sFRCs could be a suitable biomimetic material to replace dentine.

Osteoporosis and Normocalcemic Primary Hyperparathyroidism (Conservatively or Surgically Managed).

Asymptomatic primary hyperparathyroidism (PHPT) involves 80-90% of the parathyroid tumor-associated cases of PHPT in the modern medical era, while normocalcemic PHPT (NPHPT) has a prevalence of 0.1-11%. We aimed to analyze the bone status and mineral metabolism in NPHPT amid conservative or surgical management. In this narrative review, we searched PubMed (between January 2020 and July 2024) via different keywords. Fourteen studies from the final analysis (388 patients with NPHPT; 1188 with PHPT; and 803 controls) showed that mean serum calcium levels varied between 2.57 and 2.26 mmol/L in NPHPT. Ten studies identified a similar 24 h urinary calcium in NPHPT versus hypercalcemic PHPT (HPHPT). Except for one study, a mandatory vitamin D analysis was performed, but the 25-hydroxyvitamin D cut-offs varied. Osteoporosis (n = 6 studies; N = 172 with NPHPT) was confirmed in 41.7-100% of NPHPT subjects. In surgery candidates, this rate might be overestimated. A DXA analysis was performed in eight studies (235 subjects with NPHPT, and 455 patients with HPHPT); two studies identified a lower BMD in HPHPT < NPHPT, but the results were not homogenous. A single study analyzed the TBS and found similar results in NPHPT. The prevalence of fractures (n = 9) varied between 7.4% and 42.8% in NPHPT. Bone turnover markers (N = 262 patients, n = 8 studies) showed lower bone formation markers in NPHPT versus PHPT (n = 3). Two studies analyzed the BMD and bone turnover markers following parathyroidectomy (161 patients, including 30 patients with NPHPT; mean ages over 60 years). To conclude, given the wide spectrum of complications associated with PHPT, an early diagnosis and proper management is essential. A more extensive screening in patients with osteoporosis and kidney stones might lead to the discovery of NPHPT, a more recently described form of PHPT. While it is still unclear whether NPHPT is an early stage of HPHPT or a separate entity, recent findings show similar osteoporosis and fracture occurrence, and an improvement in bone metabolism, following parathyroidectomy. More extensive prospective studies are crucial to understand the natural course of the disease, to reach a consensus regarding parathyroidectomy indications and surgery candidates' selection, and to ensure proper personalized management for these patients. With the evolving diagnosis methods, PHPT has become a condition with a changing clinical presentation, which now requires modern evaluation and treatment approaches.

The Effect of Bi Addition on the Electromigration Properties of Sn-3.0Ag-0.5Cu Lead-Free Solder

As electronic packaging technology advances towards miniaturization and integration, the issue of electromigration (EM) in lead-free solder joints has become a significant factor affecting solder joint reliability. In this study, a Sn-3.0Ag-0.5Cu (SAC305) alloy was used as the base, and different Bi content alloys, SAC305-xBi (x = 0, 0.5, 0.75, 1.0 wt.%), were prepared for tensile strength, hardness, and wetting tests. Copper wire was used to prepare EM test samples, which were subjected to EM tests at a current density of approximately 0.6 × 104 A/cm2 for varying durations. The interface microstructure of the SAC305-xBi alloys after the EM test was observed using an optical microscope. The results showed that the 0.5 wt.% Bi alloy exhibited the highest ultimate tensile strength and microhardness, improving by 33.3% and 11.8% compared to SAC305, respectively, with similar fracture strain. This alloy also displayed enhanced wettability. EM tests revealed the formation of Cu6Sn5 and Cu3Sn intermetallic compounds (IMCs) at both the cathode and anode interfaces of the solder alloy. The addition of Bi inhibited the diffusion rate of Sn in Cu6Sn5, resulting in similar total IMC thickness at the anode interface across different Bi contents under the same test conditions. However, the total IMC thickness at the cathode interface decreased and stabilized with increasing EM time, with the SAC305-0.75Bi alloy demonstrating the best resistance to EM.

Assessment of concrete-to-concrete shear bond behavior using 3-D direct shear testing

The interfaces that develop when fresh concrete is poured onto existing substrates are noted for their vulnerability and influence on the durability and integrity of the composite structure. Studies on the shear bond properties and failure mechanisms of such composite concrete-to-concrete joints under normal stress are essential for developing predictive and numerical models that accommodate various levels of joint substrate roughness. This study aims to use an innovative 3D shearing box, BCR3D, to analyze the shear behavior of concrete-to-concrete joints under direct shear tests at a constant normal stress. The influence of the degree of surface roughness on the pure shear behavior of these joints was assessed at a normal stress level of 1 MPa. The substrate post-hardening surface morphology was evaluated using a high-resolution laser profilometer. Statistical surface roughness parameters were computed using MATLAB. A parametric study was carried out involving bond strength, residual shear stress, contractive-dilative behaviors, and total fracture energy. Results showed that bond strength, dilative normal displacement, and total fracture energy were proportional to the substrate surface roughness. Residual shear stress was not affected by the initial surface roughness. Dilative normal displacements were more significant for specimens with higher surface substrate roughness due to interlocking, with values reaching up to 1.77 mm. Joints with high substrate surface roughness exhibited similar bond strength and fracture energy to those obtained from the monolithic specimens, underscoring the significance of substrate preparation before casting new concrete layers.

Flexural strength, fracture toughness, translucency, stain resistance, and water sorption of 3D-printed, milled, and conventional denture base materials.

To compare mechanical, optical, and physical properties of denture base materials fabricated with various 3D printing systems to reference milled and conventionally heat-processed denture base materials. Specimens of denture base materials were either 3D-printed (DLP in-office printer, CLIP laboratory printer, or material jetting laboratory printer), milled, or heat processed. 3-point bend flexural strength testing was performed after 50 hours of water storage following 1hour of drying (dry testing) or in 37°C water (wet testing). Fracture toughness was performed with a notched beam specimen after 7 days of water storage and tested dry. The translucency parameter was measured with 2mm thick specimens. Stain resistance was measured as color change following 14 days of storage in 37°C coffee. Water sorption was measured following 7 days of storage in 37°C distilled water. For dry testing, all but one of the 3D-printed materials attained higher or equivalent flexural strength as the reference materials. For wet testing, all 3D-printed materials attained higher or equivalent strength as the reference materials and dry-tested materials. For 3D-printed materials, wet testing increased displacement before fracture whereas it decreased displacement for the reference materials. Only two of the 3D-printed materials had similar fracture toughness as the reference materials. One of the 3D-printed materials was more translucent and one was more opaque than the reference materials. Only one of the 3D-printed materials absorbed more water than the reference materials. 3D-printed denture base materials have mostly equivalent mechanical, optical, and physical properties to conventional and milled denture base materials.

Influence of Direct Coronal Restoration Materials on the Fracture Resistance of Endodontically Treated Premolars: An In Vitro Study.

(1) Background: The long-term survival of an endodontically treated tooth depends on a successful root canal treatment as well as an adequate definitive coronal restoration. This study aimed to evaluate the strength of endodontically treated premolars with mesial-occlusal-distal (MOD) cavity preparation restored with different direct coronal restoration materials but from the same manufacturer against fracture. (2) Methods: sixty intact premolars were selected and placed into five groups (n = 12): G1-intact teeth, G2-endodontic treatment and unrestored MOD cavities, G3-endodontic treatment and MOD cavities restored with Tetric PowerFlow and Tetric EvoCeram, G4-endodontic treatment and MOD cavities restored with Multicore Flow and Tetric EvoCeram, and G5-endodontic treatment and MOD cavities restored with Multicore Flow. The specimens were subjected to an axial compression load at a speed of 1.6 mm/min and optically inspected before and after with a stereomicroscope. For each premolars group, the following data were recorded: the compression resistance, the compressive strength, and the maximum force supported. The microstructure of the samples after the compression test was analyzed using scanning electron microscopy (SEM). (3) Results: statistical analysis (ANOVA and Tukey test) showed that there was a statistically significant difference between G1 and the other groups. Even though there was no statistically significant difference between the restored groups, a better mechanical behavior was registered within the G3. (4) Conclusions: this in vitro study indicated that none of the materials used can lead to a higher or at least similar fracture resistance as the intact teeth. The coronal restoration only with nano-hybrid composites may lead to a higher therapeutic benefit for the fracture-susceptible premolars.

A new strain-based approach to investigate the size and geometry effects on fracture resistance of rocks

In this paper, a new strain-based criterion is suggested for assessing the effects of size and geometry of specimen on the fracture resistance of rocks under mixed-mode (I/II) loading. The new approach named the modified maximum tangential strain (MMTSN) criterion is based on the classical maximum tangential strain (MTSN) criterion, in which the first non-singular term (T) of Williams series expansion is considered in addition to the singular terms (K). Furthermore, to provide more coherence, the critical distance (rc) from the crack tip is defined according to a new strain-based failure model. Unlike similar strain-based fracture models available in the literature, the critical distance rc in the MMTSN criterion is assumed to be size-dependent and a semi-empirical formulation is utilized for describing this size-dependency. To assess the ability of MMTSN for considering the size and geometry effects, the experimental data existing in the literature for a number of cracked Brazilian disk (CBD) and semi-circular bend (SCB) specimens manufactured from Guiting limestone are taken into account. It is demonstrated that the MMTSN criterion can predict the experimental data very well by taking into consideration the size and geometry effects without needing to calculate the other higher order terms.

Treatment options for unstable posterior pelvic ring lesions: A multicenter retrospective cohort study of the Italian Society for the Traumatology of the Pelvis

PurposePosterior pelvic ring lesions are a common finding in patients with pelvic trauma, representing a challenging condition for trauma surgeons. Surgical options are different and there is not yet evidence about the best option. Aim of the study are: (i) to compare Lumbopelvic fixation (LPF) and ilio-sacral screw fixation (ISS) regarding clinical and radiological outcome in unstable posterior pelvic ring injuries, both as whole population and single similar fracture types according to Tile classification (C1vsC1, C2vsC2, C3vsC3); (ii) to analyze clinical outcomes and complications in lumbopelvic fixation group, comparing open and closed reduction technique. MethodsA retrospective multicenter study was performed. Data of the patients were collected. Inclusion criteria were: (i) unstable posterior ring lesions Tile C type, (ii) surgically treated either through ISS (Group A) or LPF (Group B), (iii) minimum follow-up 12 months. Radiological evaluation was made through plain radiographs in Antero-posterior (AP), inlet and outlet views. Last clinical evaluation at 12 months was assessed through Majeed Score, and quality of life (QoL) through SF-12. ResultsGroup A was represented by 76 patients, and Group B by 42. Group B had better result in Majeed score for non-workers (average 60.1 ± 21.6 vs 65.0 ± 15.6, p = 0.016*). Comparing only C3-type lesions, Group A showed a higher rate of implants breakage (p = 0.032*). Other differences had p > 0.05. Comparing patients underwent open (ORIF) or closed (CRIF) reduction in Group B, CRIF group had shorter hospitalization (47.2 vs 23.4 days, p = 0.020*), an earlier full weight-bearing recovery (4.1 vs 2.6 months, p = 0.035*) and a better Majeed score in workers patients (70.3 vs 82.8, p = 0.019*). Better results for CRIF group were also recorded in quality of life (QoL), both in mental (45.1 vs 55.2, p = 0.040*) and physical outcome (31.9 vs 50.7, p < 0.001*). ConclusionISS and LPF represent both good choices in posterior pelvic ring lesions, however some significant differences were noted. LPF seems to be preferable if the patient did not work before the trauma, due to better clinical outcome. In Tile C3 lesions, LPF have lower breakage rates. If LPF is chosen, CRIF provides better clinical outcomes, QoL and lower hospitalization.

Variation in Treatment of Young Adult Distal Radius Fractures by Pediatric and Adult Orthopaedic Surgeons.

There remains a lack of consensus on the optimal treatment of isolated distal radius fractures in young adults. The primary aim of this study was to identify differences in treatment of isolated distal radius fractures in patients aged 17 to 21 years treated by adult versus pediatric orthopaedic surgeons. The secondary aim was to identify whether there is a variation in utilization of open reduction and internal fixation (ORIF) versus closed reduction and percutaneous pinning when treated surgically by adult versus pediatric orthopaedic surgeons. Patients aged 17 to 21 years with isolated distal radius fractures who were treated by adult or pediatric orthopaedic surgeons at 1 of 3 hospitals were identified through retrospective chart review. 72 patients in the pediatric surgeon cohort and 64 patients in the adult surgeon cohort were included. Demographic details were recorded, and radiographs from the initial clinic visit and final follow-up were obtained. Bivariate analysis was used to evaluate for primary and secondary aims. 40 of 136 patients were treated surgically. Bivariate analysis showed that factors associated with surgical treatment were treatment by an adult orthopaedic surgeon, higher body mass index, radiographic severity, AO classification, intraarticular involvement, distal radial-ulnar joint involvement, and meeting AAOS clinical practice guideline surgical criteria. Factors associated with ORIF compared with closed reduction and percutaneous pinning included treatment by an adult orthopaedic surgeon, older age, higher body mass index, and greater articular step-off. In comparable cohorts of young adult patients with distal radius fractures with similar fracture characteristics, there was notable variation in treatment between adult and pediatric orthopaedic surgeons. Surgical treatment was used more by adult surgeons, and when treated surgically, ORIF was used more by adult surgeons. Variation among surgeons illustrates the persistent lack of consensus on the optimal treatment in this population and highlights the need for additional research on this topic to guide management. Level IV.

Influence of viscosity and fiber reinforcement of resin composite on fracture strength and failure mode of restored molars.

To evaluate the fracture behavior of human molars with extensive MOD restorations using short-fiber-reinforced resin composite of varying viscosities. Human molars were randomly divided into seven groups (n = 12): intact teeth (control); restoration using conventional high-viscosity resin composite without (Filtek Z350XT, 3M) or with fibers (everX Posterior, GC); conventional low-viscosity resin composite without (Filtek Supreme Flowable, 3M) or with fibers (everX Flow Dentin Shade, GC); bulk-fill low-viscosity resin composite (Filtek Bulk Fill Flow, 3M) or with fibers (everX Flow Bulk Shade, GC). Restorations were performed on extensive MOD preparations, following the manufacturers' recommendations for each material. Specimens underwent fracture strength testing (N) and fracture pattern (%) categorized as repairable, possibly repairable, or non-repairable. Results were analyzed using a generalized linear model (N) and Fisher's exact test (%), with α = 0.05. Restorations performed with high-viscosity materials showed fracture strength values similar to the control and higher than those of restorations using low-viscosity resin composites (p < 0.0001), except for the bulk-fill low-viscosity resin composite with fibers (p > 0.05). Teeth restored using low-viscosity resin composite with fibers showed a higher % of repairable and possibly repairable fractures than the control (p = 0.0091). The viscosity of materials mediated the fracture strength, with restorations using high-viscosity resin composites promoting values similar to the intact tooth; however, the presence of fibers influenced the fracture pattern. Teeth with MOD cavities restored with high-viscosity resin composites showed similar fracture strength to intact teeth. Fiber-reinforced low-viscosity resin composite for the base of restoration resulted in a more repairable/possibly repairable fracture pattern.

Comparative Analysis of Functional and Surgical Outcomes in Humeral Shaft Fractures: Interlocking Nailing vs. Dynamic Compression Plating

Background: Humeral shaft fractures account for about 3-5% of all fractures, with a 3.87% incidence in Bangladesh. These fractures often respond well to non-operative treatments like casts and braces due to the humerus's ability to tolerate malunion, leading to satisfactory outcomes. However, surgery is necessary for specific cases, including open, segmental, or pathological fractures, and when conservative treatment fails. Surgical options, like dynamic compression plates and interlocking nails, allow for quicker recovery but carry risks, including nerve damage and mechanical failure. Interlocking nails offer a less invasive option with better biomechanics but may cause shoulder complications. Aim of the study: This study aims to compare the functional and surgical outcomes of patients treated with dynamic compression plating versus those treated with interlocking nailing, to determine the most effective approach for managing humeral shaft fractures. Methods: This cross-sectional study in Department of Orthopaedic Surgery, Bangabandhu Sheikh Mujib Medical University, Bangladesh, conducted from [11/12/2022] to [20/12/2023], involved 60 patients with humerus diaphyseal fractures, divided into two groups: Group A (30 patients treated with dynamic compression plating) and Group B (30 patients treated with interlock nailing). Participants were selected based on strict inclusion/exclusion criteria, and informed consent was obtained. The study evaluated various clinical factors using standard surgical techniques. Data analysis was performed using SPSS software, with significance determined at p &lt;0.05. Result: A prospective observational study at a tertiary care center involved 60 patients with humeral diaphyseal fractures, divided into two groups: 30 treated with dynamic compression plating (Group A) and 30 with interlocking nailing (Group B). Most participants were under 30, predominantly male, with no significant differences in age or gender distribution. Group B showed better blood management, while Group A had superior shoulder function but more shoulder stiffness. Both groups had similar operative times, elbow performance, and fracture union rates. Neurovascular deficits were more common in Group A. The study highlights different outcomes between the two treatment methods. Conclusion: This study evaluated clinical outcomes in patients, primarily under 30 years old, with a higher incidence in males and right-sided fractures. Dynamic compression plating led to longer surgeries, more significant blood loss, higher union rates, and more shoulder stiffness. Interlock nailing resulted in fewer neurovascular deficits but reduced shoulder function postoperatively.

Romosozumab followed by denosumab versus denosumab only: a post hoc analysis of FRAME and FRAME extension.

Osteoanabolic-first treatment sequences are superior to oral bisphosphonates for fracture reduction and bone mineral density (BMD) gain. However, data comparing osteoanabolic medications, with the more potent antiresorptive, denosumab (DMAb), are limited. We analyzed FRAME and FRAME Extension data to assess BMD and fracture incidence in patients treated with romosozumab (Romo) followed by DMAb (Romo/DMAb) versus DMAb (DMAb/DMAb) for 24months. In FRAME, women aged ≥55years (total hip [TH] or femoral neck [FN] T-score: -2.5 to -3.5) were randomized to Romo or placebo for 12months followed by DMAb for 12months. In FRAME Extension, both cohorts received DMAb for another 12months. This post hoc analysis compared BMD change and fracture incidence in patients on Romo/DMAb (months 0-24) versus DMAb/DMAb (months 12-36). Patient characteristics were balanced by propensity score weighting (PSW) and sensitivity analyses were conducted using PSW with multiple imputation (PSW-MI) and propensity score matching (PSM). Unmeasured confounding was addressed using E-values. After PSW, over 24months, compared with DMAb/DMAb, treatment with Romo/DMAb produced significantly greater BMD increases at the lumbar spine [LS], TH, and FN (mean differences: 9.3%, 4.4%, and 4.1%, respectively; all p<0.001). At month 24, in women with a baseline T-score of -3.0, the probability of achieving a T-score > -2.5 was higher with Romo/DMAb versus DMAb/DMAb (LS: 92% versus 47%; TH: 50% versus 5%). In the Romo/DMAb versus DMAb/DMAb cohorts, new vertebral fractures were significantly reduced (0.62% versus 1.26% [odds ratio = 0.45; p=0.003]) and rates of clinical, nonvertebral, and hip fractures were lower (differences not significant). Similar BMD and fracture outcomes were observed with PSW-MI and PSM sensitivity analyses. The sequence of Romo/DMAb resulted in greater BMD gains and higher probability of achieving T-scores > -2.5, significantly reduced new vertebral fracture incidence, and numerically lowered the incidence (not significant) of clinical, nonvertebral, and hip fractures versus DMAb only through 24months.

Microstructure and properties of SLMed Ta-10W and rolled Ta-10W fiber laser welded joint

This study focused on the mechanical properties and microstructure of fiber laser-welded joints of Ta-10W alloy manufactured by selective laser melting (SLM) and rolled. In the SLMed base material side of the weld, columnar grains were formed along the weld, extending up to half of the weld width. The base material’s anisotropy influenced the subgrain morphology, and grain orientation changed after welding. When the building direction of the SLMed Ta-10W was perpendicular to the welding direction, slender columnar subgrains were prone to forming in the SLM side weld. In contrast, when the building direction was parallel to the welding direction, equiaxed subgrains tended to form in the weld. In the rolling base material side weld, mainly equiaxed grains were formed, with subgrain morphology and orientation randomly distributed. In the weld center, fine-grain zones of 10–20 μm, comprising fine grains of 2–5 μm diameter, were observed in all welds under study. Room-temperature tensile strengths of both welds were approximately 620 MPa, falling between the strengths of the two base materials. Their fracture surfaces displayed a mixed mode of cleavage and intergranular fracture. High-temperature strengths of rolled-SLMed joints varied with SLM directions X and Z, reaching 124.94 and 107.87 MPa, respectively, and exhibiting similar fracture characteristics dominated by intergranular fracture.

The Influence of Mallet Mass and Velocity on the Fracture Patterns in Osteotomies.

Osteotomies are routinely incorporated in rhinoplasty, however, the influence of mass, velocity, kinetic energy (KE), and momentum (p) of the mallet on fracture patterns has not been studied. An experimental sledge guillotine setup was designed simulating a mallet strike with adjustable height and mass and 2 mm-thick Sawbone blocks. KE and p were calculated using KE = ½ mass × velocity2 and p = mass × velocity formulas. Fracture lengths and angles were measured. Ten groups with varying mallet masses and drop heights were tested with 10 bones per group. Fracture length positively correlated with KE (R = 0.542, p < 0.001) and p (R = 0.508, p < 0.001). Fracture angle also positively correlated with KE (R = 0.367, p < 0.001) and p (R = 0.329, p < 0.001). In groups with similar KE, osteotomies with higher p (heavier mallet with slower velocity) had greater fracture lengths (29.31 ± 0.68 vs. 27.68 ± 2.12 mm, p = 0.013) but similar fracture angles (p = 0.189). In groups with similar p, osteotomies with higher KE (lighter hammer with faster velocity) had significantly greater fracture lengths (28.28 ± 1.28 vs. 20.45 ± 12.20 mm, p = 0.041) and greater divergent fracture angles (3.13 ± 1.97° vs. 1.40 ± 1.36°, p = 0.031). Regression modeling of the relationship between KE and fracture lengths and angles demonstrated that cubic followed by logarithmic regression models had the best fits. Osteotomy fracture patterns positively correlated with the mallet's KE more so than its p, suggesting that the mallet's velocity has an increased impact effect than its mass. Clinically, a heavier mallet with a lower velocity will likely generate a smaller fracture length and fracture angle, indicating a more controlled and ideal fracture. NA Laryngoscope, 135:97-103, 2025.

Fracture resistance of ultratranslucent multilayered zirconia veneers with different facial thicknesses.

To assess the fracture resistance of computer-aided design and computer-aided manufacturing (CAD/CAM) ultratranslucent multilayered zirconia (5Y-YZP) veneers with varying facial thickness. Sixty translucent zirconia veneers were designed and milled using a chairside CAD/CAM system for maxillary central incisors. The butt joint incisal veneer tooth preparations consisted of 1.00 mm incisal reduction, 0.40 mm chamfer margin, and three different facial reductions; 0.50, 0.75, and 1 mm, respectively. The ceramic veneers were cemented to printed resin dies and subjected to thermal cycling. Subsequently, the restorations were loaded with compressive loading force, and fracture occurrences were recorded. Scanning electron microscope (SEM) images of the fractured specimens were captured. The fracture resistance varied among the veneers with different facial thicknesses. Ultratranslucent zirconia veneers with a facial thickness of 1.00 mm exhibited the highest fracture resistance values (742.15 N), followed by those with 0.75 mm facial thickness (673 N). Minimally invasive veneers with 0.50 mm thickness displayed similar fracture resistance as thicker veneers with 0.75 mm. However, veneers with 1.00 mm thickness displayed the highest values. SEM fracture patterns for 0.50 and 0.75 mm display similar and fewer crack lines than 1.00 mm veneers. RESEARCH HIGHLIGHTS: Minimally invasive zirconia veneers exhibit similar fracture resistance to thicker veneers.

Effect of preparation design on the fracture resistance and fracture patterns of 3D printed one-piece endodontic crowns

Statement of problemThe impact of various preparation designs on the fracture resistance and fracture type of mandibular premolars restored with 3 dimensionally (3D) printed, 1-piece endodontic crowns remains unclear. PurposeThe purpose of this study was to investigate the effect of different preparation designs on the fracture resistance and fracture patterns of mandibular premolars restored with 3D printed 1-piece endodontic crowns after thermal aging. Material and methodsForty-five freshly extracted mandibular premolars received 3 different preparation designs: with at least 2 intact cuspal walls (2CW), with only 1 intact cuspal wall (1CW), and no cuspal wall present (NoCW). One-piece endodontic crowns were designed by using a computer-aided design (CAD) software program, 3D printed, cemented to the prepared teeth with self-adhesive resin cement, and thermocycled between 5 °C and 55 °C in artificial saliva. Subsequently, all specimens were subjected to a fracture test. The results were statistically analyzed using 1-way ANOVA (α=.05), and fracture types of all specimens were examined using a light microscope. ResultsThe analysis of fracture resistance values across separate designs revealed no statistically significant differences (P>.05). Mean fracture resistance values were 724.5 N in 2CW, 713 N in 1CW, and 861 N in NoCW. In 2CW and 1CW, the 1-piece endodontic crowns mostly displayed Type III fractures, whereas those in NoCW exhibited a combination of Type II and Type III fractures. ConclusionsThe mandibular premolar 1-piece endodontic crowns tested in this study exhibited similar fracture resistance and type of fracture with different preparation designs.

Fracture of the C15 CaAl2 Laves phase at small length scales

The cubic C15 CaAl2 Laves phase is an important brittle intermetallic precipitate in ternary Mg–Al–Ca structural alloys. Although knowledge of the mechanical properties of the co-existing phases is essential for the design of improved alloys, the fracture toughness of the C15 CaAl2 intermetallic has not yet been studied experimentally due to limitations posed by macroscale testing of defect-free specimens. Here, miniaturised testing techniques like micropillar splitting and microcantilever bending methods are used to experimentally determine the fracture toughness of the CaAl2 Laves phase. It is found that the toughness value of ~ 1 MPa·√m obtained from pillar splitting with a sharp cube corner geometry is largely insensitive to sample heat treatment, the ion beam used during fabrication, micropillar diameter, and surface orientation. From correlative nanoindentation and electron channelling contrast imaging supported by electron backscatter diffraction, fracture is observed to take place mostly on {011} planes. Atomistic fracture simulations on a model C15 NbCr2 Laves phase showed that the preference of {011} cleavage planes over the more energetically favourable {111} planes is due to lattice trapping and kinetics controlling fracture planes in complex crystal structures, which may provide insights into the experimental results for CaAl2. Using rectangular microcantilever bending tests where the notch plane was misoriented to the closest possible {112} cleavage plane by ~ 8° and the closest {001}, {011}, and {111} planes by > 20°, a toughness of ~ 2 MPa·√m was determined along with the electron microscopy observation of significant deviations of the crack path, demonstrating that preferential crystallographic cleavage planes determine the toughness in this material. Further investigation using pentagonal microcantilevers with precise alignment of the notch with the cleavage planes revealed similar fracture toughness values for different low-index planes. The results presented here are the first detailed experimental study of fracture toughness of the C15 CaAl2 Laves phase and can be understood in terms of crack plane and crack front-dependent fracture toughness.Graphical