A flexible single‐crystalline PMN‐PT piezoelectric energy
harvester is demonstrated to achieve a self‐powered artificial cardiac pacemaker. The energy‐harvesting device generates a short‐circuit ...current of 0.223 mA and an open‐circuit voltage of 8.2 V, which are enough not only to meet the standard for charging commercial batteries but also for stimulating the heart without an external power source.
Deep brain stimulation (DBS) is widely used for neural prosthetics and brain-computer interfacing. Thus far in vivo implantation of a battery has been a prerequisite to supply the necessary power. ...Although flexible energy harvesters have recently emerged as alternatives to batteries, they generate insufficient energy for operating brain stimulation. Herein, we report a high performance flexible piezoelectric energy harvester by enabling self-powered DBS in mice. This device adopts an indium modified crystalline Pb(In sub(1/2)Nb sub(1/2))O sub(3)-Pb(Mg sub(1/3)Nb sub(2/3))O sub(3)-PbTiO sub(3 ) (PIMNT) thin film on a plastic substrate to transform tiny mechanical motions to electricity. With slight bending, it generates an extremely high current reaching 0.57 mA, which satisfies the high threshold current for real-time DBS of the motor cortex and thereby could efficiently induce forearm movements in mice. The PIMNT based flexible energy harvester could open a new avenue for future in vivo healthcare technology using self-powered biomedical devices.
While regional voxel-based registration (R-VBR) has been shown to have excellent reproducibility and angular accuracy, there are limited data on the linear accuracy of R-VBR for common orthognathic ...surgery landmarks, or on whether angular accuracy correlates with linear accuracy. The purpose of this study was to estimate the linear accuracy of R-VBR for several skeletal landmarks commonly used in orthognathic surgical planning, and to measure the correlation between angular and linear discrepancies.
This is a retrospective cross-sectional study of consecutive patients treated at a single center with nonsegmental LeFort I and bilateral sagittal split osteotomy surgery from January 2019 to November 2020. Cone beam computed tomography at the preoperative (T0) and immediate postoperative (T1) stages were analyzed to measure the postoperative positional changes of 11 orthognathic landmarks in 4 regions of interest (ROI) using R-VBR performed twice by two examiners. Pairwise correlation analysis and canonical correlation analysis were performed for the angular discrepancies (primary predictor variable) and the linear discrepancies (primary outcome variable) to measure the correlation between the two.
In cone beam computed tomography analysis of 28 eligible subjects (16 males, 12 females; mean age 18.9 years, range 15 to 25), the mean absolute (MA) angular discrepancies ranged from 0.15° to 0.55°, while the corresponding MA linear discrepancies ranged from 0.05 to 0.41 mm. There was a strong correlation between angular and linear discrepancies that was statistically significant (P = .001 to .04, Spearman's rank correlation coefficient 0.38 to 0.87).
For nonsegmental LeFort I osteotomies and bilateral sagittal split osteotomy, R-VBR has excellent linear accuracy within a single voxel size (0.3 mm) for commonly used orthognathic landmarks in the maxillary and distal mandibular ROI. The MA linear discrepancy for the proximal mandibular segment ROI was greater than a single voxel size, with a maximum of 0.41 mm.
Incorporating bioactive molecules into synthetic ceramic scaffolds is challenging. In this study, to enhance bone regeneration, a magnesium phosphate (MgP) ceramic scaffold was incorporated with a ...novel indene compound, KR-34893. KR-34893 induced the deposition of minerals and expression of osteoblast marker genes in primary human bone marrow mesenchymal stem cells (BMSCs) and a mouse osteoblastic MC3T3-E1 cell line. Analysis of the mode of action showed that KR-34893 induced the phosphorylation of MAPK/extracellular signal-regulated kinase and extracellular signal-regulated kinase, and subsequently the expression of bone morphogenetic protein 7, accompanied by SMAD1/5/8 phosphorylation. Accordingly, KR-34893 was incorporated into an MgP scaffold prepared by 3D printing at room temperature, followed by cement reaction. KR-34893-incorporated MgP (KR-MgP) induced the expression of osteoblast differentiation marker genes in vitro. In a rat calvaria defect model, KR-MgP scaffolds enhanced bone regeneration and increased bone volume compared with MgP scaffolds, as assessed by micro-computed tomography and histological analyses. In conclusion, we developed a method for producing osteoinductive MgP scaffolds incorporating a bioactive organic compound, without high temperature sintering. The KR-MgP scaffolds enhanced osteoblast activation in vitro and bone regeneration in vivo.
The 3-dimensional (3D) accuracy of computer-assisted planning (CAP) of segmental maxillary osteotomies has seldom been reported with a comprehensive 3D analysis. The aim of the present study was to ...measure the accuracy of computer-planned segmental maxillary surgery and to identify the factors associated with accuracy.
The present retrospective, cross-sectional study investigated cone-beam computed tomography (CBCT) scans of patients who had undergone segmental maxillary osteotomy with CAP at a single center from January 2013 to October 2019. The predictor variables were age, gender, diagnosis, CAP method, type of maxillary segmentalization, surgeon, surgical sequence, and magnitude of planned and actual movements. The primary outcome variable was surgical discrepancy (linear differences between the actual and planned maxillary movements using CAP in the x, y, and z coordinates) at various 3D landmarks. The mean difference and absolute mean difference (AMD) were computed to estimate the direction and magnitude of the discrepancies. In addition, a 2.0-mm threshold of surgical discrepancy was used to determine clinically acceptable accuracy. The association between the predictor and outcome variables were analyzed statistically using correlation and regression analyses.
The sample included 63 patients (mean age, 20.1 years; 42.9% male). The surgical discrepancy was similar for 2- and 3-piece segmental maxillary osteotomies. Overall, the AMD for all patients was 0.96 ± 0.69 mm transversely, 1.23 ± 0.83 mm vertically, and 1.16 ± 0.80 mm anteroposteriorly (P < .01 for all). The discrepancy between the actual and planned movements was within 2.0 mm for more than 80% of cases. The major predictor variable that affected surgical discrepancy was the magnitude of the actual surgical movements (P < .01).
3D CAP showed clinically acceptable accuracy for segmental maxillary osteotomies comparable to that of nonsegmental cases. Although the magnitude of actual surgical movements was shown to affect surgical accuracy, the sources of surgical discrepancies requires further investigation.
Purpose
In asymmetrical mandibles, it is often challenging to identify the mandibular midline. The median lingual foramen (MLF) is located at the midline of the anterior mandible. The purpose of this ...study is to evaluate the reproducibility of identifying the MLF compared to conventional landmarks on cone beam computed tomography's (CBCT's) to mark the mandibular midline.
Material and Methods
Ten symmetrical class II, 10 symmetrical class III, ten asymmetrical class II and 10 asymmetrical class III patients were included. On CBCTs, the cephalometric landmarks menton, pogonion, genial tubercle and MLF were identified twice by two observers.
Results
A high intra‐ and interobserver reproducibility was found for all landmarks, the highest being the MLF. The gain in accuracy is 0.998 mm, 0.824 mm and 0.361 mm compared to pogonion, genial tubercle and menton, respectively (P‐value <.05).
Conclusion
MLF is a reliable and reproducible landmark to indicate the midline of the mandible, particularly in Class II asymmetric mandibles.
Objective
It is unclear whether surface bioactive chemistry or hydrophilicity plays a more dominant role in the osseointegration of micro‐structured titanium implants having the same surface ...topography at the micrometer and submicrometer scales. To understand their comparative effect on enhancing the early osseointegration of micro‐rough‐surfaced implants, this study compared the bone healing‐promoting effect of surface strontium (Sr) chemistry that has been shown in numerous studies to super‐hydrophilicity in the early osseointegration of moderately rough‐surfaced clinical oral implants (SLA® implant) in rabbit cancellous bone.
Material and methods
Hydrothermal treatment was performed to incorporate Sr ions into the surface of clinical SLA implants (SLA/Sr implant). The surface characteristics were evaluated by using field emission‐scanning electron microscopy, X‐ray photoelectron spectroscopy and optical profilometry. Twenty screw implants (10 control and 10 experimental) were placed in the femoral condyles of 10 New Zealand White rabbits. The early osseointegration of the SLA/Sr implant was compared with a chemically modified super‐hydrophilic SLA implant (SLActive® implant) by histomorphometric and resonance frequency analysis after 2 weeks of implantation.
Results
The SLA/Sr and SLActive implants exhibited an identical surface topography and average Ra values at the micron and submicron scales. The SLA/Sr implant displayed a high amount of surface Sr content (15.6 at.%). There was no significant difference in the implant stability quotient (ISQ) values between the two groups. However, histomorphometric analysis revealed a significantly higher bone‐to‐implant contact percentage in the SLA/Sr implants compared with the SLActive implants in rabbit cancellous bone (P < 0.01).
Conclusion
The results indicate that the surface Sr chemistry surpasses the effect of super‐hydrophilicity in promoting the early bone apposition of moderately rough Ti surface in cancellous bone.
Background
There is a growing interest in factors leading to implant failure in older people as the population aged 65 years or older continues to expand.
Purpose
We sought to identify differences of ...results in the implant survival rate and the influence of certain factors on implant failure in the older (≥65 years) and younger (<65 years) patients.
Materials and Methods
Patients who underwent their first dental‐implant surgery between July 2008 and June 2018 were included. Data on age, sex, smoking habits, medical conditions, implant location, implant size, and the presence and type of bone graft and membrane were collected and analyzed according to age group. Moreover, cumulative survival rates of implants (by Kaplan‐Meier analysis) and hazard ratios (HR) of each factor (using Cox regression analysis with shared frailty) in each group were assessed and results compared between groups.
Results
A total of 628 implants in 308 patients and 1904 implants in 987 patients in the older and younger groups, respectively, were assessed, with failure rates of 3.9% and 3.4%. Per Kaplan‐Meier analysis, the 11‐year patient‐level cumulative survival rate of implant treatment was 95.3% (95% CI: 0.91‐0.97) in the older and 93.9% (95% CI: 0.88‐0.97) in the younger group. The HR for implant failure of the variables, except diameter of dental implants, were not statistically significant in both groups.
Conclusion
The outcomes of implant treatment were not considerably different between the age groups.
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