Plant immunity suppression by an ß-1,3-glucanase of the maize anthracnose pathogen Colletotrichum graminicola.

BACKGROUND: Many phytopathogens secrete a large number of cell wall degrading enzymes (CWDEs) to decompose host cell walls in order to penetrate the host, obtain nutrients and accelerate colonization. There is a wide variety of CWDEs produced by plant pathogens, including glycoside hydrolases (GHs), which determine the virulence, pathogenicity, and host specificity of phytopathogens. The specific molecular mechanisms by which pathogens suppress host immunity remain obscure. RESULT: In this study, we found that CgEC124 encodes a glycosyl hydrolase with a signal peptide and a conserved Glyco_hydro_cc domain which belongs to glycoside hydrolase 128 family. The expression of CgEC124 was significantly induced in the early stage of Colletotrichum graminicola infection, especially at 12 hpi. Furthermore, CgEC124 positively regulated the pathogenicity, but it did not impact the vegetative growth of mycelia. Ecotopic transient expression of CgEC124 decreased the disease resistance and callose deposition in maize. Moreover, CgEC124 exhibited the ß-1,3-glucanase activity and suppresses glucan-induced ROS burst in maize leaves. CONCLUSIONS: Our results indicate that CgEC124 is required for full virulence of C. graminicola but not for vegetative growth. CgEC124 increases maize susceptibility by inhibiting host reactive oxygen species burst as well as callose deposition. Meanwhile, our data suggests that CgEC124 explores its ß-1,3-glucanase activity to prevent induction of host defenses.

Polyvinyl Chloride-Based Luminescent Downshifting Film with High Flame Retardancy and Excellent UV Resistance for Silicon Solar Cells.

Solar power generation, as a clean energy source, has significant potential for development. This work reports the recent efforts to address the challenge of low power conversion efficiency in photovoltaic devices by proposing the fabrication of a luminescence downshifting layer using polyvinyl chloride (PVC) with added fluorescent dots to enhance light utilization. A photoluminescent microsphere (HCPAM) is synthesized by cross-linking hexachlorocyclotriphosphazene, 2-iminobenzimidazoline, and polyethyleneimine. Low addition of HCPAM can improve the fire safety of PVC films, raising the limiting oxygen index of PVC to 32.4% and reducing the total heat release and smoke production rate values by 14.5% and 42.9%, respectively. Additionally, modified PVC film remains a transparency of 88% and shows down-conversion light properties. When the PVC+1%HCPAM film is applied to the solar cell, the short-circuit current density increases from 42.3 to 43.8 mA cm-2, resulting in a 7.0% enhancement in power conversion efficiency. HCPAM also effectively delays the photooxidative aging of PVC, particularly at a 3% content, maintaining the surface morphology and optical properties of PVC samples during ultraviolet aging. This study offers an innovative strategy to enhance the fire and UV-resistant performance of PVC films and expand their applications in protecting and efficiently utilizing photovoltaic devices.

In Situ Growth Strategy to Construct "Four-In-One" Separators with Functionalized Polyphosphazene Coatings for Safe and Stable Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) are facing many challenges, such as the inadequate conductivity of sulfur, the shuttle effect caused by lithium polysulfide (LiPSs), lithium dendrites, and the flammability, which have hindered their commercial applications. Herein, a "four-in-one" functionalized coating is fabricated on the surface of polypropylene (PP) separator by using a novel flame-retardant namely InC-HCTB to meet these challenges. InC-HCTB is obtained by cultivating polyphosphazene on the surface of carbon nanotubes with an in situ growth strategy. First, this unique architecture fosters an enhanced conductive network, bolstering the bidirectional enhancement of both ionic and electronic conductivities. Furthermore, InC-HCTB effectively inhibits the shuttle effect of LiPSs. LSBs exhibit a remarkable capacity of 1170.7 mA h g-1 at 0.2 C, and the capacity degradation is a mere 0.0436% over 800 cycles at 1 C. Third, InC-HCTB coating serves as an ion migration network, hindering the growth of lithium dendrites. More importantly, InC-HCTB exhibits notable flame retardancy. The radical trapping action in the gas phase and the protective effect of the shielded char layer in the condensed phase are simulated and verified. This facile in situ growth strategy constructs a "four-in-one" functional separator coating, rendering InC-HCTB a promising additive for the large-scale production of safe and stable LSBs.

A Fluorination Strategy and Low-Acidity Anchoring Group in Self-Assembled Molecules for Efficient and Stable Inverted Perovskite Solar Cells.

Herein, we synthesized two donor-acceptor (D-A) type small organic molecules with self-assembly properties, namely MPA-BT-BA and MPA-2FBT-BA, both containing a low acidity anchoring group, benzoic acid. After systematically investigation, it is found that, with the fluorination, the MPA-2FBT-BA demonstrates a lower highest occupied molecular orbital (HOMO) energy level, higher hole mobility, higher hydrophobicity and stronger interaction with the perovskite layer than that of MPA-BT-BA. As a result, the device based-on MPA-2FBT-BA displays a better crystallization and morphology of perovskite layer with larger grain size and less non-radiative recombination. Consequently, the device using MPA-2FBT-BA as hole transport material achieved the power conversion efficiency (PCE) of 20.32 % and remarkable stability. After being kept in an N2 glove box for 116 days, the unsealed PSCs' device retained 93 % of its initial PCE. Even exposed to air with a relative humidity range of 30±5 % for 43 days, its PCE remained above 91 % of its initial condition. This study highlights the vital importance of the fluorination strategy combined with a low acidity anchoring group in SAMs, offering a pathway to achieve efficient and stable PSCs.

Air pollution and skin diseases: A comprehensive evaluation of the associated mechanism.

Air pollutants deteriorate the survival environment and endanger human health around the world. A large number of studies have confirmed that air pollution jeopardizes multiple organs, such as the cardiovascular, respiratory, and central nervous systems. Skin is the largest organ and the first barrier that protects us from the outside world. Air pollutants such as particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs) will affect the structure and function of the skin and bring about the development of inflammatory skin diseases (atopic dermatitis (AD), psoriasis), skin accessory diseases (acne, alopecia), auto-immune skin diseases (cutaneous lupus erythematosus(CLE) scleroderma), and even skin tumors (melanoma, basal cell carcinoma (BCC), squamous-cell carcinoma (SCC)). Oxidative stress, skin barrier damage, microbiome dysbiosis, and skin inflammation are the pathogenesis of air pollution stimulation. In this review, we summarize the current evidence on the effects of air pollution on skin diseases and possible mechanisms to provide strategies for future research.

Antisolvent-Free Heterogenous Nucleation Enabled by Employing 4-Tert-Butyl Pyridine Additive and Two-Step Annealing for Efficient CsPbI2 Br Perovskite Solar Cells.

All inorganic perovskite based on CsPbI2 Br has attracted significant attention due to its relatively thermal stable structure compare to its hybrid counterparts. With a wide bandgap of 1.9 eV and excellent light absorption capability, it has been extensively explored for applications in indoor photovoltaics and as a front absorber in tandem devices. However, the uncontrollable crystallization process during solvent evaporation and thermal annealing leads to both macroscopic defects like cracks and microscopic defects such as voids. In this study, a metastable adduct with lead (II) halides by incorporating 4-tert-butyl pyridine as a volatile Lewis base monodentate ligand in the precursor solution is formed. The strategic preferential decomposition of the adduct during the early-stage low-temperature annealing facilitated the desorption of lead (II) halides, inducing antisolvent-free heterogenous nucleation. This, in turn, promoted crystal growth during subsequent high-temperature annealing, resulting in dense films with low defect density. As a result, a maximum open-circuit voltage of 1.30 V is achieved with the champion power conversion efficiency of 16.5% in CsPbI2 Br-based perovskite solar cell. The work reveals a new mechanism of using Lewis acid-base adduct to obtain high quality perovskite films other than hindering crystallization in traditional way.

An IRF2BP member (CgIRF2BP) involved in negative regulation of CgIFNLP expression in oyster Crassostrea gigas.

The IRF2BP family of transcription regulators act as corepressor molecules by inhibiting both enhancer-activated and basal transcription involving in many biological contexts. In the present study, an IRF2BP homologue (CgIRF2BP) was identified from oyster C. gigas. Its open reading frame is of 1809 bp encoding a polypeptide of 602 amino acids, which contains an IRF-2BP1_2 domain and a RING domain. The mRNA transcripts of CgIRF2BP were detected in all tested tissues with highest level in haemocytes (28.99-fold of that in mantle, p < 0.05). After poly (I:C) stimulation, the expression level of CgIRF2BP was significantly down-regulated at 3 h (0.50-fold of that in control group, p < 0.001) and gradually increased from 6 h to 48 h (2.69-fold of that in control group, p < 0.01). The recombinant protein of CgIRF2BP (rCgIRF2BP) showed high affinity to both rCgIRF1 and rCgIRF8 with Kd value of 1.02 × 10-7 and 2.09 × 10-7, respectively. In CgIRF2BP-RNAi oysters, the mRNA expression of CgIFNLP, CgMx1, CgViperin and CgIFI44L were significantly increased after poly (I:C) stimulation, which were 2.88 (p < 0.01), 1.83 (p < 0.05), 2.47 (p < 0.05), and 1.99-fold (p < 0.01) of that in EGFP group, respectively. These findings suggested that CgIRF2BP negatively regulated CgIFNLP expression by binding with CgIRF1 and CgIRF8.

An ATP-binding cassette transporter G2 (CgABCG2) regulates the haemocyte proliferation by modulating the G1/S phase transition of cell cycle in oyster Crassostrea gigas.

ATP-binding cassette transporter G2 (ABCG2) is a half-transporter of the G subfamily in ATP-binding cassette transporters (ABC transporter), which is involved in the regulation of multidrug-resistant, cell cycle, and cell proliferation. In the present study, a homologue of ABCG2 (named as CgABCG2) with the conserved AAA domain and ABC2 membrane domain was identified from the Pacific oyster Crassostrea gigas. The open reading frame (ORF) of CgABCG2 was of 1956 bp encoding a predicted polypeptide of 652 amino acids, which shared 56.7%-65.7% sequence similarities with previously identified ABCG2s from other animals. The mRNA transcripts of CgABCG2 were detected in all the tested tissues with higher expression levels in gonad and haemocytes (19.31-fold and 11.23-fold of that in adductor muscle respectively, p < 0.05). CgABCG2 was mainly distributed on the cell membrane of the haemocytes with a partial distribution in the cytoplasm and nucleus. After Vibrio splendidus stimulation, the mRNA expression level of CgABCG2 in haemocytes was significantly up-regulated at 3 h and 6 h, which was 5.22-fold and 8.60-fold (p < 0.05) of that in control, respectively. After the expression of CgABCG2 was interfered by RNAi, the number of cells with EdU positive signals was reduced in both haemocytes and the potential hematopoietic sites. And the mRNA expression level of CgPCNA, CgGATA3, CgRunx, CgSCL and CgC-kit decreased significantly (p < 0.05), which were about 0.66-, 0.37-, 0.32-, 0.50-, and 0.50-fold of that in the negative control group, respectively. While the mRNA expression level of CgCDK2 increased significantly (1.84-fold to that in control, p < 0.05) and that of stem cell-related factor CgSOX2 did not change significantly in the si-CgABCG2 oysters. Moreover, the cell cycle of haemocytes was detected by flow cytometry, which was arrested at G0/G1 phase in the si-CgABCG2 oysters. All the results collectively suggested that CgABCG2 might involve the proliferation of haemocytes by regulating the expression of haematopoiesis related transcription factors and the G1/S phase transition of the cell cycle in oyster C. gigas.

A randomized, double-blind, placebo-controlled phase II study to evaluate the efficacy and safety of ivarmacitinib (SHR0302) in adult patients with moderate-to-severe alopecia areata.

BACKGROUND: Alopecia areata (AA) is a CD8+ T cell-mediated autoimmune disease characterized by nonscarring hair loss. Ivarmacitinib, which is a selective oral Janus kinase 1 inhibitor, may interrupt certain cytokine signaling implicated in the pathogenesis of AA. OBJECTIVE: To evaluate the efficacy and safety of ivarmacitinib in adult patients with AA who have ≥25% scalp hair loss. METHODS: Eligible patients were randomized 1:1:1:1 to receive ivarmacitinib 2, 4, or 8 mg once daily or placebo for 24 weeks. The primary end point was the percentage change from baseline in the Severity of Alopecia Tool score at week 24. RESULTS: A total of 94 patients were randomized. At week 24, the least squares mean difference in the percentage change from baseline in the Severity of Alopecia Tool score for ivarmacitinib 2, 4, and 8 mg and placebo groups were -30.51% (90% CI, -45.25, -15.76), -56.11% (90% CI, -70.28, -41.95), -51.01% (90% CI, -65.20, -36.82), and -19.87% (90% CI, -33.99, -5.75), respectively. Two serious adverse events-follicular lymphoma and COVID-19 pneumonia-were reported. LIMITATIONS: A small sample size limits the generalizability of the results. CONCLUSION: Treatment with ivarmacitinib 4 and 8 mg doses in patients with moderate and severe AA for 24 weeks was efficacious and generally tolerated.

A first-principles study of the structural, electronic and elastic properties of the FeO2-FeO2He system under high pressure.

The origin of the wave velocity anomalies at the core-mantle boundary (CMB) has been controversial. The primordial helium reservoir in the deep lower mantle remains elusive even with geochemical evidence for its existence. Here, we calculated the density and wave velocity of the FeO2-FeO2He system under the CMB conditions using first principles. The FeO2 and FeO2He of pyrite-type can exist stably under the CMB conditions without melting, and the incorporated helium increases the stability of the system. The electrical properties of FeO2 and FeO2He are not related to pressure. Doped helium reduces the density of the system but increases the elastic modulus. Our results suggest that FeO2 can be used as a viable material composition of ultra-low velocity zones (ULVZs), and FeO2He can explain the D'' seismic discontinuity instead of ULVZs. The primordial helium reservoir possibly formed by the accumulation of FeO2He, the only stable solid helium-bearing compound under the CMB conditions, may coincide with the location of the D'' layer.

Association of air pollution and genetic risks with incidence of elderly-onset atopic dermatitis: A prospective cohort study.

BACKGROUND: Elderly-onset atopic dermatitis (AD) is a remarkable subtype and has been put on the agenda owing to its difficulty to control. Understanding the influence of genetic and environmental exposures is crucial to preventing elderly-onset AD. OBJECTIVES: To explore the association between genes and air pollution on incident elderly-onset AD. MATERIAL AND METHODS: This study was based on UK Biobank that recruited over 500,000 participants. The genetic risks were categorized into low, intermediate, and high groups according to tertiles of polygenic risk scores. Mixed exposure to various air pollutants was assessed using the weighted quantile sum (WQS) and also categorized based on tertiles. Within each genetic risk group, whether air pollutant mixture was associated with incident elderly-onset AD was estimated. RESULTS: 337,910 participants were included in the final analysis, and the mean age was 57.1. The median years for follow-up were 12.0, and the incident cases of AD were 2545. The medium and high air pollution mixture was significantly associated with incident AD compared with the low pollution group, with HRs of 1.182 (P = 0.003) and 1.359 (P < 0.001), respectively. In contrast, HR for medium and high genetic susceptibility was only 1.065 (P = 0.249) and 1.153 (P = 0.008). The population-attributable fraction of air pollution and genetic risk was 15.5 % (P < 0.001) and 6.4 % (P = 0.004). Additionally, compared with low genetic risk and low air pollution, high genetic risk and high air pollution was significantly associated with the incidence of elderly-onset AD with a HR of up to 1.523 (P < 0.001). There were no interactive effects between each group of genetic risks and air pollution. When grouped by sex, females could observe a stronger effect by genetic and air pollutant mixture exposure. CONCLUSION: Air pollution and genetics both independently enhance the risk of newly developed AD, and the effect of air pollutants is stronger than the investigated genes.

Study on the biodegradation of polybutylene adipate-co-terephthalate/starch film containing deep eutectic solvent.

Poly (butylene adipate-co-terephthalate) (PBAT) has attracted much attention as a biodegradable polymer, but its biodegradation speed is slow. Starch was blended with PBAT to develop daily packing film with high biodegradation speed, and deep eutectic solvent (DES) composed of choline chloride (CHCl)/glycerol (Gly) (molar ratio of 1:2) was used as a novel plasticizer. The hydrophilic starch is in favor of the breeding of microorganisms, at the same time DES can provide energy for the breeding. The degradation was traced in a simulated composting test using kitchen waste. After the PBAT/starch-DES film was buried in a mixture of food residue for 90 D, the relative weight molecular weight (Mw) of the PBAT decreased by about 50%. Furthermore, with the help of DES, the compatibility between PBAT and starch was improved, the PBAT/starch-DES film became more transparent than the PBAT and PBAT/starch film, and its tensile strength reached 7.9 MPa with an elongation at break of 335.6%. This work provided a simple and efficient solution to obtain rapidly degradable films.

Study on the Flame Retardancy of Rigid Polyurethane Foam with Phytic Acid-Functionalized Graphene Oxide.

A rigid polyurethane foam (RPUF) composite was prepared by compounding phytic acid (PA)-functionalized Graphite oxide (PA-GO) with flame-retardant poly (Ammonium phosphate) (APP) and expandable graphite (EG). The effects of PA-GO on the thermal, flame-retardant, and mechanical properties of RPUF were studied using a thermogravimetric analyzer, a limiting oxygen index (LOI) tester, a UL-94 vertical combustion tester, a cone calorimeter, scanning electron microscopy, and a universal tensile testing machine. The results indicated that there was a significant synergistic flame-retardant effect between PA-GO and the intumescent flame retardants (IFR) in the RPUF matrix. Compared with RPUF-1, the addition of 0.3 wt% PA-GO could increase LOI from 25.7% to 26.5%, increase UL-94 rating from V-2 to V-0, and reduce the peak heat release rate (PHRR) and total heat release rate (THR) by 28.5% and 22.2%, respectively. Moreover, the amount of residual char increased from 22.2 wt% to 24.6 wt%, and the char layer was continuous and dense, with almost no holes. Meanwhile, the loss of mechanical properties was apparently lightened.

A Facile Immobilization Strategy for Soluble Phosphazene to Actualize Stable and Safe Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) have attracted extensive attention owing to their high energy density and abundant sulfur resources. However, LSBs are still restricted by the unsatisfactory electrochemical performance resulting from the shuttle effect of lithium polysulfide (LiPSs), and the potential fire hazard caused by inflammable ether electrolytes and polyolefin separators. Herein, a facile immobilization strategy for hexachlorocyclotriphosphazene (HCCP) is creatively applied to address the above issues simultaneously. Insoluble HCCP cross-linked microspheres (H-CMP) are firstly obtained at ambient temperature using tannic acid (TA) as a cross-linking agent and then a multifunctional separator coating is constructed based on H-CMP. The released phosphorus-related radicals from H-CMP in wide temperatures effectively prevent the combustion of electrolytes and separators, and hence improve the fire safety of the Li-S pouch cell. Furthermore, H-CMP availably chemisorbs LiPSs to interdict the shuttle effect, thereby dramatically improving the electrochemical performance of LSBs. The effectiveness of this strategy is also verified in high sulfur loading (6.38 mg cm-2 ), high temperature (50 °C), and Li-S pouch cells. More importantly, H-CMP exhibits sufficient stability for Li metal and suppression of Li dendrites. This facile immobilization strategy for multifunctional phosphazenes provides a competitive option for the large-scale fabrication of high-safety and high-performance LSBs.

Phototherapy for atopic dermatitis: Systematic review and network meta-analysis of randomized controlled trials.

BACKGROUND: Phototherapies could represent an efficient option for the treatment of atopic dermatitis (AD), but the evidences available for clinical choices were contradictory. OBJECTIVE: This study aimed to evaluate the efficacy of different phototherapies on AD. METHODS: This systematic review and network meta-analysis included randomized controlled trials (RCTs) through searching keywords from PubMed, EMBASE, and the Cochrane library. We summarized different phototherapy types and scoring systems. Scoring Atopic Dermatitis (SCORAD) absolute score changes were estimated by mean differences (MDs) and standard deviations (SDs) and then included in the network meta-analysis. The effect sizes of comparison of different phototherapies were presented as MDs and 95% confidence intervals (CIs). Egger's test was used to evaluate publication bias. RESULTS: Eleven RCTs were included in the systematic review and 4 studies in the network meta-analysis. Based on the pooled estimates, medium-dose ultraviolet A1 (UVA1) cold light was superior to medium-dose UVA1 (MD 8.92; 95% CI: 5.60-12.24) but no significant difference between high-dose (UVA1) and medium-dose UVA1 cold light (MD 0.66; 95% CI: -5.57 to 6.90). Publication bias was not supported by Egger's test (P = .168). CONCLUSIONS: Due to possible long-term adverse effects of high-dose UVA1, medium-dose UVA1 cold light appears to be the superior form for AD.

Self-intumescent polyelectrolyte for flame retardant poly (lactic acid) nonwovens.

The demand for eco-friendly poly (lactic acid) (PLA) nonwovens grows at a high rate in the past several decades, however, only a little attention has been received for flame retardant PLA nonwoven fabrics. In this work, a novel halogen-free self-intumescent polyelectrolyte tris (hydroxymethyl)-aminomethane polyphosphate (APTris) was synthesized by reacting ammonium polyphosphate with tris (hydroxymethyl) aminomethane, and was then used to improve the fire resistance of PLA nonwovens via a dip-nip process. The flammability characterization indicated the limiting oxygen index value was increased to 30.0% from 18.3%, and the damaged area in the vertical burning test was reduced by about 87.0% by the presence of APTris. The cone calorimeter test results revealed that the peak heat release rate and total heat release of the treated sample were decreased by 41.0% and 28.2% respectively compared with that of the control PLA nonwoven sample. The char residue was increased to 12.3 from 1.7 wt % at 800 °C. It is suggested that the dense char barrier formed at the presence of APTris prevents heat, smoke, and gas transfer, and hence enhance thermal dilatability and flame retardancy of PLA nonwovens. This simple sustainable halogen-free treatment has great potential to produce cleaner commercialized flame-retardant PLA nonwovens.

Time-resolved in situ monitoring of photocatalytic reactions by probe electrospray ionization mass spectrometry.

Probe electrospray ionization mass spectrometry (PESI-MS) has been demonstrated to be a useful in situ and online analytical technique for monitoring of various reactions. In this work, PESI-MS with a surface-modified probe was adopted and applied to in situ monitoring of photocatalytic reactions. Typical reactions of semiconductor photocatalysts, namely TiO2, SnO2, WO3, SiC and ZnS catalyzed methylene blue (MB) and brilliant green (BG) degradation, were selected to demonstrate the potential of PESI-MS to monitor heterogeneous photocatalytic reactions occurring in suspensions. Surface modification of the probe ensures increased wettability during the whole monitoring process. PESI-MS could provide continuous sampling and real-time MS results without time-consuming and cumbersome sample pretreatments. This method has other merits including good reproducibility and stability (time scale > 60 min), convenience of operation, low sample consumption, high time resolution and high tolerance to suspended photocatalyst particles. Time-resolved mass spectra and ion chromatograms of every chemical species e.g. the substrate and reactive intermediates could be obtained, which is helpful for a better understanding of the photocatalytic reaction process. Thus, PESI-MS could be a versatile analytical technique for in situ photocatalytic reaction analysis and could be an alternative means for the evaluation of photocatalyst performance.

Accuracy of the evaluation of implant position using a completely digital registration method compared with a radiographic method.

STATEMENT OF PROBLEM: Conventional radiographic methods are widely used to evaluate the clinical accuracy of implant position. However, such methods require a second computerized tomography (CT) scan and manual registration between presurgical and postsurgical CT data. The alignment errors cannot be calculated. PURPOSE: The purpose of this clinical study was to introduce a completely digital registration method to evaluate the clinical accuracy of implant position. The digital registration method was then compared with the radiographic method in evaluating accuracy. Some of the alignment errors produced in the digital registration procedures were recorded. MATERIAL AND METHODS: A total of 32 implants from 19 patients with sufficient bone volume were enrolled in the study, and all implant surgeries were conducted by one experienced practitioner. Before the surgery, a cone beam computerized tomography (CBCT) scan was made for each patient along with a diagnostic impression to design the ideal implant position using the Simplant software. After the surgery, the postsurgical implant position was determined using an optical scan of the dentition cast and a series of custom registration models (the digital registration method). A simulated cylinder was designed using the Geomagic Studio software to represent the implant, and the deviation of the ideal and postsurgical implant position was calculated. The accuracy evaluated by the 2 methods was also compared. The parameters of the entrance point, apical point, and axis were recorded for each implant. A part of the alignment errors in the digital registration was calculated automatically and recorded. One sample t test and paired t test were conducted by using a statistical software program. RESULTS: The mean deviation between the ideal and postsurgical implant positions evaluated using the digital registration method was 0.84 ±0.57 mm for the entrance point, 1.03 ±0.78 mm for the apical point, and 4.52 ±2.37 degrees for the angulation. No significant difference was found between the accuracy evaluated by the digital registration method and the radiographic method (P>.05). In the digital registration procedure, the alignment error was 0.03 mm for the registration model and 0.29 mm for the dentition. Significant differences were found in the alignment procedure of the impression cylinder (P<.001) and dentition (P<.001). The average positive and negative errors were +0.09 and -0.19 mm for the simulated cylinder of the ideal implant and +0.08 and -0.15 mm for the simulated cylinder of the postsurgical implant. CONCLUSIONS: The precision of the digital registration method could be accepted in clinical applications. No significant difference was found between the digital registration method and the radiographic method in evaluating the clinical accuracy of the implant position. The digital registration method was able to control and minimize the alignment errors produced during data processing.

Factors that Influence Direction Deviation in Freehand Implant Placement.

PURPOSE: This retrospective study investigates the accuracy of freehand implant placement and whether the factors of presence of an adjacent tooth, implant quadrant, number of missing teeth, and location of the implant site influence direction and angulation deviations. MATERIALS AND METHODS: According to specific inclusion and exclusion criteria, a total of 112 implants from 75 partially edentulous patients were recruited for this retrospective study. The implants were inserted using a freehand approach by one experienced clinician (right-handed). The full thickness flap was elevated to expose the alveolar bone in the implant surgery, and the implant crown consisted of an all-ceramic restoration retained by cement. The planned implant position was preoperatively determined using implant planning software. The postoperative implant position was determined by analyzing the alignment after optically scanning the dentition using a specifically designed registration model in Geomagic Studio software. The deviations between the planned and postoperative implant positions were then calculated. The outcomes included direction and angulation deviations between the planned and postoperative implant positions. All data were analyzed by ANOVA, Bonferroni correction, regression analysis, and one-sample t-tests conducted using SPSS. RESULTS: The 3D deviations between planned and postoperative implant positions were 1.22 ± 0.63 mm at the entrance point, 1.91 ± 1.17 mm at the apical point, and 7.93 ± 5.56° in angulation. The presence of adjacent teeth influenced deviations in the mesiodistal (F = 4.338, p = 0.006) and buccolingual directions (F = 3.017, p = 0.033) at the entrance point and mesiodistal angulation (F = 7.979, p < 0.001). The quadrant influenced deviation in the buccolingual direction at the apical point (F = 6.093, p = 0.001) and buccolingual angulation (F = 6.457, p < 0.001). The number of missing teeth had no effect on deviations of direction and angulation of implants. The location of the implant site affected the deviation in the buccolingual direction at the entrance point (F = 3.096, p = 0.049) and the mesiodistal direction at the apical point (F = 3.724, p = 0.027). CONCLUSION: The 3D accuracy of freehand-placed implants could be acceptable in clinical situations. The results showed that the presence of an adjacent tooth and the quadrant and the location of the implant site influenced the direction and angulation deviations of the implant position; however, the factor of number of missing teeth did not.