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Choosing four or six implants to support immediate full-arch fixed prostheses (FAFPs) is still controversial worldwide. This study aims to analyze and compare the long-term results of All-on-4 and All-on-6.This retrospective cohort study enrolled 217 patients rehabilitated with 1222 implants supporting 271 FAFPs, including 202 prostheses supported by 4 implants (All-on-4 group) and 69 prostheses supported by 6 implants (All-on-6 group), and followed up for 3-13 years. Implant survival, prosthesis survival, complications, and implant marginal bone loss (MBL) were evaluated and compared between two groups. Patient characteristics including age, gender, jaw, opposite dentition condition, smoking habit, bruxism, bone quantity and quality, cantilever length (CL), prosthesis material, and oral hygiene were analyzed to assess their influence on the clinical results of the two groups. Six surgeons and three prosthodontists who performed FAFPs more than 5 years were invited for questionnaires, to assess patient- and clinician-related influences on implant number.In general, All-on-4 group indicated no significant difference with All-on-6 group in the implant survival (implant-level: hazard ratio [HR] = 1.0 [95% confidence interval (CI): 0.8-1.2], P = 0.96; prosthesis-level: HR = 0.8 [95% CI: 0.3-1.8], P = 0.54), prosthesis survival (odds ratio [OR] = 0.8 [95% CI: 0.3-2.8], P = 0.56), biological complications (OR = 0.9 [95% CI: 0.5-1.8], P = 0.78), technical complications of provisional prosthesis (OR = 1.3 [95% CI: 0.7-2.3], P = 0.42), technical complications of definitive prosthesis (OR = 1.1 [95% CI: 0.6-2.2], P = 0.33) and the 1st, 5th, and 10th year MBL (P = 0.65, P = 0.28, P = 0.14). However, for specific covariates, including elderly patients, opposing natural/fixed dentition, smoking, bruxism, long CL, low bone density, and all acrylic provisional prostheses, All-on-6 was more predictable in some clinical measurements than All-on-4. The implant prosthodontists and the medium-experienced clinicians showed significant preference for All-on-6 (P 0.05).Based on this study, the long-term clinical results showed no significant difference between All-on-4 and All-on-6 groups in general. However, for some specific characteristics, All-on-6 seemed to be more predictable in some clinical measurements than All-on-4. For the clinicians' decision-making, medium-experienced clinicians and the implant prosthodontists showed significant preference for All-on-6.

Intraoral scanning has benefits over conventional impression making, but whether scanning is sufficiently accurate for multiple implants is unclear.The purpose of this in vitro study was to compare the trueness of digital scans acquired by using intraoral scanners from a small range to a complete arch with the conventional impression technique and to determine the influence of 2 different evaluation methods (best-fit algorithm versus absolute linear deviation) on the outcomes of accuracy assessment.A mandibular model with 8 implants (A-H) around an edentulous arch was used as the master model. Open-format standard tessellation language (STL) data sets (1 reference file from a highly accurate dental laboratory scanner, 10 files from an intraoral scanner, and 10 files from digitized conventional impressions at room temperature) were imported to a metrology software program, and 5 groups of scanning ranges (AB, FGH, CDEF, BCDEFG, and ABCDEFGH) were identified simulating different clinical situations. Two evaluation methods-root mean square values calculated from the best-fit algorithm and average value of linear discrepancies from absolute linear deviation-were used to describe the trueness values. The impacts of different scanning or impression methods, ranges, and evaluation methods were tested by using a 3-way ANOVA. The effect of the scanning range on accuracy was further identified with 1-way ANOVA. The paired-sample t test was used to determine the differences of trueness values between the 2 methods in different groups.The trueness values of the implant impressions were significantly affected by different scanning or impression methods (P.001), evaluation methods (P.001), and scanning ranges (P.001) as independent variables. With use of the best-fit algorithm, deviations from the digital scans were significantly greater than those from the conventional impressions in cross-arch situations (groups CDEF, BCDEFG, and ABCDEFGH). With use of the absolute linear deviation method, statistically significant lower accuracy was found when larger areas were encountered (groups BCDEFG and ABCDEFGH). Use of the absolute linear deviation method resulted in a higher mean score of inaccuracy than that from the best-fit algorithm method in most situations.Scanning or impression methods, ranges, and evaluation methods affected the dimensional accuracy (trueness) of scans or impressions with multiple implants. Digital scans had worse trueness values compared with those made with the conventional splinting open-tray technique when cross-arch implant impressions were acquired.

Statement of problem Three-dimensionally printed custom open trays have become a popular option in clinical implant dentistry because of advantages such as individualization, efficiency, and effectiveness. However, clinical evidence on their accuracy and feasibility is lacking. Purpose The purpose of this clinical study was to evaluate the accuracy and feasibility for impressions of multiple implants by using 3D-printed custom open trays versus conventional custom open trays. Material and methods Twenty-two partially edentulous individuals needing impression making for restorations supported by multiple implants were enrolled. Two types of custom open trays were made for each participant, a 3D-printed tray (test) and a conventional tray (control). With a splinted technique, silicone definitive impressions were obtained with the 2 custom open trays and poured with Type IV dental stone. Impression accuracy (primary outcome) was evaluated by measuring linear distances and the marginal gaps between the implant replicas and verification devices on the test and control casts. Clinical tray fit, impression quality, and cast quality were rated by an independent technician through a visual analog scale (VAS). The fabrication time and cost of the 2 types of custom open trays were recorded. The feasibility of 3D-printed trays was determined from these outcomes. The paired Student t test and Wilcoxon rank-sum tests were used for statistical analysis (α=.05). Results For impression accuracy, no statistically significant difference was found between test and control groups (P>.05). In terms of clinical tray fit, impression quality, and cast quality, no statistically significant difference was found (all P>.05). Regarding fabrication time and cost, the test group (57.65 ±6.49 minutes, 0.37 ±0.07 United States dollars [USD]) exhibited superiority over the control group (101.96 ±2.92 minutes, 4.41 ±0.37 USD) (both P Conclusions Within the limitations of this study, the 3D-printed custom open trays were clinically accurate, efficient, and cost-effective for impressions of multiple implants.

(85-x)WC–15 wt%Al2O3–xTiC (x = 0, 1.5, 2.5, 5, 10, and 20 wt%) composites were prepared by vacuum hot-press sintering. The influence of TiC addition on the corrosion behaviour of WC–Al2O3 composites in 0.1 M NaOH solution was revealed. The results suggest that all the samples containing added TiC had the TiC phase and (W, Ti) C solid-solution phase, while the base composite had neither phase. With increasing added TiC content, the average grain size of WC decreased, and the relative density first increased and then decreased. Furthermore, the results suggest that the addition of TiC could noticeably increase the free corrosion potential and impedance and reduce the corrosion current density. However, the composite containing 20 wt% added TiC showed the opposite trend. Therefore, it can be concluded that the corrosion performance of the composites in an alkaline medium can be improved by adding an appropriate amount of TiC. The change in corrosion properties was caused by changes in the solid-solution phase, relative density, and TiO2 oxide film.

Background With the emergence of three-dimensional (3D) integration technology, analysis of soft tissue displacement and morphological changes after maxillary full-arch implant-supported fixed prostheses can be performed. The aim of this study was to verify the feasibility of the 3D integration method for constructing the relative position of the prostheses and facial soft tissue, evaluate the displacement and morphological variation of the upper lips after maxillary full-arch implant-supported fixed prostheses. Methods Twenty-five maxillary edentulous patients were recruited in this study. At the time of final prosthesis delivery, the 3D prostheses data and three 3D facial profiles were integrated. After method validation, the 3D position changes of seven soft tissue landmarks were used to reflect the 25 upper lips. The variation of four morphological distances were analyzed to reflect the morphological alteration of the upper lips. Two pairs of dentofacial landmarks were used to analyze the sagittal relative position of the prostheses and soft tissue. The included patients were also grouped to determine the impact of sex, upper lip thickness, and length on lip support changes. Results The average distance of the two matched relative reliable forehead regions was only 0.32 mm. The sagittal shifts of labrale superius (LS), stomion (STO), crista philtri left (CPHL) and crista philtri right (CPHR) were 3.44 ± 1.39 mm, 2.52 ± 1.38 mm, 3.04 ± 1.18 mm, and 3.12 ± 1.21 mm, respectively. With the exception of the decrease in the length of subnasale (SN)-LS, the length of cheilion right (CHR)-cheilion left (CHL), CPHR-CPHL, and LS-STO significantly increased. The two pairs of dentofacial landmarks had strong positive movement correlations along the sagittal direction. Patients with thinner and longer lips showed more lip support than those with thicker and shorter lips by a clinically insignificant amount. Conclusions The integration method of 3D facial and dental data showed high repeatability in constructing the dentofacial relative position. The linear equations reflecting dentofacial relative position could aid clinicians in evaluating the restoration effect and estimate the upper lip variation.

Titania nanotubes (TNTs) fabricated on titanium orthopedic and dental implants have shown significant potential in "proof of concept"iin vitro/i,iex vivo/i, and short-termiin vivo/istudies. However, most studies do not focus on a clear direction for future research towards clinical translation, and there exists a knowledge gap in identifying key research challenges that must be addressed to progress to the clinical setting. This review focuses on such challenges with respect to anodized titanium implants modified with TNTs, including optimized fabrication on clinically utilized microrough surfaces, clinically relevant bioactivity assessments, and controlled/tailored local release of therapeutics. Further, long-termiin vivo/iinvestigations in compromised animal models under loading conditions are needed. We also discuss and detail challenges and progress related to the mechanical stability of TNT-based implants, corrosion resistance/electrochemical stability, optimized cleaning/sterilization, packaging/aging, and nanotoxicity concerns. This extensive, clinical translation focused review of TNTs modified Ti implants aims to foster improved understanding of key research gaps and advances, informing future research in this domain.

In this study, the densification during the formation of WC-based coating prepared by electric contact strengthening (ECS) was investigated. Under increasing ECS process unit time, the surface and cross-sectional morphology, element distribution, hardness and phase composition of WC-based coating were detected. And the wear tests were conducted to test the coating performance. The results showed that, with the prolongation of ECS time, the coatings became denser while the porosity ratio decreased from 10.14% to 1.05%; The hardness of the coatings increased and the worn loss decreased continuously. It was found that, by the heating-pressing action of ECS, the WC-based powder geometry could maintain the original sphere shape, while the pores were filled gradually. The A4 coating showed the lowest wear rate. The densification mechanism was deduced that the intensified capillarity at the interface between the hard phase and binder phase due to the heating-pressing action, which showed forced infiltration and creeping behavior of the binding phase.

A comparative study on the corrosion behavior of novel WC-MgO composite and WC-6Co cemented carbide was carried out in 3.5 wt% NaCl solution with immersion and electrochemistry method. The result indicates that WC-MgO composite possesses higher corrosion resistance than WC-6Co cemented carbide. The key reason for higher corrosion resistance of WC-MgO composite is the dense and flat WO3 passive film which can protect inner material to avoid further corrosion successfully. The main corrosion mechanism for WC-MgO composite is typical pitting and oxidation of WC phase. The reaction of MgO and Cl− promotes the dissolution of MgO phase, which is the main reason of pitting formation. For WC-6Co cemented carbide, the corrosion products are porous, which cannot protect inner material to avoid further corrosion. The difference of corrosion mechanism can be attributed to the replacing of Co binder with MgO, which avoids the formation of galvanic corrosion between WC and Co.

The corrosion behavior of WC-MgO composite in H2SO4 and NaOH solution has been studied with electrochemistry and microstructure analysis method. The aim of this work is to explore the corrosion behavior and mechanism of WC-MgO whisker composite in acid and alkali solution. The result suggests that WC-MgO composite possesses higher corrosion resistance in H2SO4 solution than in NaOH solution. The key reason for better corrosion resistance in H2SO4 solution is the stable WO3 passive film. The oxidation of WC leads to corrosion induced crack along with grain boundaries. It can be attributed to the preferential corrosion of grain boundary and volume expansion caused by WC phase oxidation. The corrosion induced crack on the surface may decrease mechanical properties of WC-MgO composite. In NaOH solution, the main corrosion mechanism is the dissolution of WC phase but MgO is relatively stable.

WC–Al2O3 composites with 0, 0.1 wt%, 0.5 wt% and 0.9 wt% graphene platelets were fabricated in order to compare their tribological behavior. Friction and wear results were obtained on the composite flats sliding against the WC–Co cemented carbide under 50 N load using a reciprocating ball-on-disk tribometer. The experimental results indicate that the compacted layers with cracks form on the wear surfaces of all the composite bulks. The WC–Al2O3 composites with 0.1 wt% and 0.5 wt% graphene platelets possess lower friction coefficient and wear rate, which can be attributed to the lubrication and protection of graphene tribofilm as well as their higher mechanical properties. Graphene tribofilm cannot form on the wear surface of WC–Al2O3 composite with 0.9 wt%, due to the agglomeration tendency of graphene and its lower mechanical properties.

In this study, WC-Al2O3 composite was fabricated by vacuum hot-pressing sintering. The corrosion behavior of WC-Al2O3 composite in NaOH and H2SO4 solutions was investigated by electrochemical measurements. The corrosion mechanisms were analyzed and revealed in light of corrosion morphology observation and composition characterization. The results confirmed that WC-Al2O3 composite possessed higher corrosion resistance than WC-Co hard metal in H2SO4 solution. Conversely, WC-Al2O3 composite behaved similar corrosion resistance compared with WC-Co hard metal in NaOH solution. The key reason for higher corrosion resistance in H2SO4 solution is the stable WO3 passive film. The oxidation of WC phase leads to neck cracks along with grain boundaries, which is attributed to the preferential corrosion of grain boundary and the stress derived from the volume expansion during polarization and drying processes. In NaOH solution, the corrosion mechanism of WC-Al2O3 composite mainly attributed to the dissolution of WC phase, but Al2O3 phase is relatively stable.

Complement cascade plays an important role in the field of transfusion medicine. The study aimed to detect the complement levels of different blood components and different blood types to explore the risk of transfusion of stored blood. The samples including red blood cells (n = 110), fresh frozen plasma (n = 120), and platelet concentrates (n = 104) from healthy blood donors in our center were collected. Complement components (C3, C4, C3b, C3d, and CH50) were assayed to evaluate the activation of complement. The complement levels of various blood components at different storage times were observed. The differences in complement levels of four blood types in various blood components were compared. The complement levels of red blood cells in storage were low, with no significant changes (P > 0.05). C3b and C3d levels in platelets began to significantly increase after storage for 3 days (P 0.05), but the C3b and C3d levels of AB fresh frozen plasma remained stable during storage, which different from other blood types. The transfusion of red blood cells was relatively safe in terms of complement activation. The activation of complement proteins occurred during the storage of platelet and plasma, except group AB plasma. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s12288-020-01338-0) contains supplementary material, which is available to authorized users.

Aims To evaluate the hard and soft tissue alterations of immediately placed and provisionalized implants with or without connective tissue graft (CTG). Materials and methods Single unsalvageable maxillary incisors were replaced with immediately placed and provisionalized implants in 42 participants. The patients were randomly assigned to receive simultaneous CTG (test group) and not receive CTG (control group). Digital impression and cone-beam computed tomography images were obtained before extraction and after 6 months. Mid-facial gingival margin migrations, soft tissue contour changes and hard tissue remodelling were analysed and compared between the two groups using three-dimensional superimposition method. Results Forty participants completed the study. The test group showed significantly less buccal tissue collapse in the area 2-5 mm apical to the gingival margin. In both groups, the mid-facial gingival margin migrated in an apico-palatal direction and the socket void, except for a triangular space in the bucco-coronal region, demonstrated radiographic new bone formation without statistically significant differences. Conclusions The CTG used with immediate implant placement and provisionalization could compensate for the facial tissue collapse, but it did not benefit maintenance of the mid-facial gingival margin position during the 6-month follow-up. New bone formation observed radiographically can be expected in most areas of the socket void, regardless of CTG use (ChiCTR-1900028494).

Advanced mechanical and tribological properties are the premises for the novel WC-Al2O3 ceramic composite without metallic binder phase to be industrially applied. For this purpose, 0.3 wt% graphene platelets were doped during the fabrication of WC-Al2O3 ceramic composite in this work. Characterization showed graphene platelets were homogeneously distributed in the ceramic matrix. Graphene platelets additions refined the grain size, increased the hardness (from 16.18 to 18.34 GPa) and fracture toughness (from 8.08 to 11.02 MPa m1/2). Graphene platelets additions reduced the friction coefficient (from 0.47 to 0.28, under 40 N; from 0.57 to 0.38, under 60 N) and the specific wear rate (from 1.21 × 10−5 to 1.32 × 10−6mm3N−1m−1, under 40 N; from 2.18 × 10−5 to 6.72 × 10−6mm3N−1m−1, under 60 N), based on the ball-on-disk dry sliding.

Ginseng is regarded as the “king of herbs” in China, with its roots and rhizomes used as medicine, and it has a high medicinal value. In order to meet the market demand, the artificial cultivation of ginseng emerged, but different growth environments significantly affect the root morphology of garden ginseng. In this study, we used ginseng cultivated in deforested land (CF-CG) and ginseng cultivated in farmland (F-CG) as experimental materials. These two phenotypes were explored at the transcriptomic and metabolomic levels so as to understand the regulatory mechanism of taproot enlargement in garden ginseng. The results show that, compared with those of F-CG, the thickness of the main roots in CF-CG was increased by 70.5%, and the fresh weight of the taproots was increased by 305.4%. Sucrose, fructose and ginsenoside were significantly accumulated in CF-CG. During the enlargement of the taproots of CF-CG, genes related to starch and sucrose metabolism were significantly up-regulated, while genes related to lignin biosynthesis were significantly down-regulated. Auxin, gibberellin and abscisic acid synergistically regulated the enlargement of the taproots of the garden ginseng. In addition, as a sugar signaling molecule, T6P might act on the auxin synthesis gene ALDH2 to promote the synthesis of auxin and, thus, participate in the growth and development of garden ginseng roots. In summary, our study is conducive to clarifying the molecular regulation mechanism of taproot enlargement in garden ginseng, and it provides new insights for the further exploration of the morphogenesis of ginseng roots.

Background: To evaluate changes in hard and soft tissue during the first 6 months after immediate implant placement and provisionalization (IIPP) of a single maxillary incisor.Methods: Failed maxillary incisors were replaced with IIP implants in 34 patients. Intraoral scans and cone beam computed tomography (CBCT) were performed before and 6 months after IIPP. Changes in soft tissue thickness, soft tissue contour, and hard tissue contour were measured by a three-dimensional superimposition method. The correlations of hard and soft tissue contour changes were assessed.Results: A total of 31 patients completed the study. Soft tissue contour tended to collapse after 6 months. Soft tissue was significantly thickened 1–3 mm below the gingival margin. Correlation analysis showed strong correlations between the hard and soft tissue contour changes at 0–5 mm apical to the implant platform. The mid-facial recession at 6 months was −0.46 ± 0.55 mm.Conclusions: Soft tissue contour collapsed after tooth extraction, regardless of IIPP. Both soft and hard tissue change affected the soft tissue contour change.

Computer-aided design and computer-aided manufacturing (CAD-CAM) monolithic restorative materials have become a popular option because of advantages such as convenience and efficiency. However, studies that quantitatively analyzed their color accuracy and bias are lacking.The purpose of this in vitro study was to evaluate the color accuracy and bias of 4 CAD-CAM monolithic restorative materials with different thicknesses by using the CIELab color space.Four types of dental CAD-CAM monolithic restorative materials in shade A2, lithium disilicate glass-ceramic (IPS e.max CAD), infiltrated ceramic (VITA Enamic), resin-nano ceramic (LAVA Ultimate), and polymethyl methacrylate (Telio CAD), were prepared as 12×12-mm specimens of 10 different thicknesses (from 0.5 to 5.0 mm) (N=200, n=5). After polishing with SiC P1500-grit, CIELab color coordinate parameters of the specimens were measured with a spectrophotometer (VITA Easyshade V). The color accuracy and bias were described by ΔEThe ΔEThe color accuracy and bias were significantly affected by material type and thickness. The color inaccuracy of the tested materials was statistically significant and clinically perceptible. Improved clinical outcomes may be expected from the 1.5-mm- to 2.0-mm-thick restorations.

Purpose This is a clinical study to compare complete digital workflows generated using intraoral scanning and the split-file technique with a conventional workflow for cement-retained implant-supported restorations. Materials and methods Forty patients requiring posterior single-unit implant restorations were included. Twenty patients were randomly assigned to the complete digital workflow group, involving intraoral scanning and manufacture of cement-retained crowns using the split-file technique (test group). The remaining 20 patients were assigned to the hybrid workflow group (control group), involving conventional impressions and CAD/CAM-fabricated crowns based on stone casts. Scanning of the crowns was performed before and after clinical adjustment using an intraoral scanner (TRIOS Color; 3Shape). Two 3D digital models were trimmed and superimposed to evaluate changes in dimensions using Geomagic Control 2014 software. Chair-side and laboratory times for the entire workflow were recorded. Independent-sample t tests were used for the statistical analysis. Results All crowns were inserted without re-fabrication. The average maximum occlusal adjustment of the crowns, measured as maximum deviation of occlusal area in superimposed pre and post scans, was -212.7 ±150.5 and -330.7 ±192.5 μm in the test and control groups, respectively (p = 0.037).The average area of occlusal adjustment, measured as area of deviation larger than 100 μm, was 8.4 ±8.1 and 17.1 ±12.3 mm2 in the test and control groups, respectively (p = 0.012). The mesial and distal contact adjustment amounts, maximum deviations of proximal area, were -33.0 ±96.2 and -48.6 ±70.5 μm in the test group, and -3.7 ±66.7 μm and -11.4 ±106.7 μm in the control group, respectively. The mean chair-side time was 20.20 ± 3.00 and 26.65 ± 4.53 min in the test and control groups, respectively (p Conclusions Single-unit cement-retained crowns with complete digital workflows required fewer crown adjustments and had shorter clinical and laboratory times compared to conventional impressions and hybrid workflows. Digital impressions and the split-file technique provided customized abutments and cement-retained crowns, thus broadening the indications for digital workflows for implants. This article is protected by copyright. All rights reserved.

Titanium (Ti) and its alloys offer favorable biocompatibility, mechanical properties and corrosion resistance, which makes them an ideal material choice for dental implants. However, the long-term success of Ti-based dental implants may be challenged due to implant-related infections and inadequate osseointegration. With the development of nanotechnology, nanoscale modifications and the application of nanomaterials have become key areas of focus for research on dental implants. Surface modifications and the use of various coatings, as well as the development of the controlled release of antibiotics or proteins, have improved the osseointegration and soft-tissue integration of dental implants, as well as their antibacterial and immunomodulatory functions. This review introduces recent nano-engineering technologies and materials used in topographical modifications and surface coatings of Ti-based dental implants. These advances are discussed and detailed, including an evaluation of the evidence of their biocompatibility, toxicity, antimicrobial activities and in-vivo performances. The comparison between these attempts at nano-engineering reveals that there are still research gaps that must be addressed towards their clinical translation. For instance, customized three-dimensional printing technology and stimuli-responsive, multi-functional and time-programmable implant surfaces holds great promise to advance this field. Furthermore, long-term in vivo studies under physiological conditions are required to ensure the clinical application of nanomaterial-modified dental implants.

To assess the accuracy of intraoral digital impressions for gingival contour captured in the esthetic zone in vivo.Five participants with full upper dentition were recruited. For each participant, three scans were taken using two intraoral scanning (IOS) systems (3Shape TRIOS Color, TRC; CEREC Omnicam, OC) respectively; three conventional impressions (CIs) were taken using vinyl polysiloxane materials. The CIs of all participants were casted and then digitized with a model scanner (IScan D103i, Imetric). Precision was evaluated by superimposing three repeated STL datasets per participant within each group and calculating the (90th-10th)percentile/2 values. The CIs were the reference for evaluating the level of system error of the two IOS systems from the true value. Digital models from CI and each IOS group were superimposed and (mean positive deviation-mean negative deviation)/2[mean negative deviation, mean positive deviation] were calculated to assess trueness level of the two IOS systems.For the soft tissue acquisition, precision results of each group were 45.10 ± 12.54 μm in TRC, 66.04 ± 13.46 μm in OC, and 63.66 ± 17.19 in CI (TRC vs OC, p0.001; TRC vs CI, p = 0.001; OC vs CI, p = 0.66). Trueness results were 80.12 ± 8.69[- 112.10 ± 9.88, 48.13 ± 13.79] μm in TRC and 82.70 ± 8.85[- 121.41 ± 15.40, 43.98 ± 11.86] μm (p0.05).In dentate situations, the two tested IOS systems achieved a clinically satisfying accuracy for capturing gingival contour in anterior maxilla, with a comparable or superior precision to the CI. TRC achieved a similar trueness and a higher precision level compared with OC.Intraoral digital impressions could be a recommended method for recording 3-dimensional gingival contour in the esthetic zone.

OBJECTIVES To compare the three-dimensional changes in quantity and morphology following clinical adjustment of a posterior single implant crown between chairside digital workflow (test) and hybrid digital workflow (control). MATERIALS AND METHODS A total of 33 participants were included for single-tooth replacement with screw-retained crowns in posterior sites of either the maxillary or mandible. A total of 17 participants were carried to a chairside digital workflow, receiving monolithic lithium disilicate (LS2)-crowns (test), while the remaining 16 participants were fitted with CAD/CAM-fabricated zirconia superstructures and hand-layered ceramic veneering crowns (control). As each crown underwent intraoral scanning (3Shape TRIOS Color, 3Shape), 3D digital models were rendered. These scans were taken both before and after try-in. Clinical adjustment dimensional changes were measured by superimposing the optical scans of models within a reverse software (Geomagic Control 2014). Adjustment counts and amounts (from vertical dimension) between two workflows were assessed and compared. Time consumption was recorded for efficiency analysis. RESULTS All patients were successfully treated in both groups. The median maximum vertical adjustment (taking both occlusal and interproximal surfaces into consideration) was 237 μm ± 112 in the test group and 485 μm ± 195 in the control group (p

To enhance the toughness of the WC-Al2O3 composite, graphene platelets (GPLs) were incorporated to this ceramic composite by using ball milling and hot pressing sintering. The influences of graphene on microstructure and mechanical properties of the WC-Al2O3 composites were investigated. Results of the experiments showed that the grain size of the composite first diminished and then increased gradually along with the increase of graphene content. Both the Vickers hardness and toughness increased first and then diminished along with the increase of graphene content. The optimized composite exhibited the highest Vickers hardness (18.78 GPa) and the highest fracture toughness (11.09 MPa·m1/2) at the indentation load of 294 N (30 kg) when incorporated with 0.3 wt% GPLs, which are about 18.7% and 40.8% higher than that of WC-Al2O3 without GPLs, respectively. However, the relative density of the WC-Al2O3 composites decreased stably along with the increase of graphene content. Agglomeration of GPLs and porosity were observed in the composites with high content, which weakened the properties. The toughening mechanisms are proposed to be crack deflection, crack bridging, graphene pull out and grain refinement.

PURPOSE To assess the three-dimensional (3D) accuracy of multi-implant impressions for complete arches obtained using 3D printing technology, and to determine the clinical feasibility of this approach by comparing the results obtained with those obtained with conventional impression techniques. MATERIALS AND METHODS A maxillary model matrix with four implant analogs was used to fabricate 10 stone reference models (control) to simulate edentulous patients. Ten 3D-printed impressions were made using polylactic acid custom open trays with component splinting (3D-printed group). To make 10 conventional impressions of the reference models, the poly(methyl methacrylate) open trays with splinting technique was used (conventional group). Impressions were poured with a type IV dental stone, which had been digitalized utilizing a high-resolution laboratory scanner after connecting the polymer scan bodies. Standard tessellation language (STL) datasets from the two groups of stone models were superimposed with the corresponding reference models. The interimplant distances and interimplant angulations for each implant pair were measured for the reference models and for the two test groups' definitive models, to assess 3D deviations. In addition, the mechanical properties of polylactic acid and poly(methyl methacrylate) tray materials were compared by means of three-point loading and tensile bond tests. The Student t test was used to compare the differences in implant position and mechanical properties between the two groups, while implant angulations were analyzed with Wilcoxon's rank-sum test, at P = .05. RESULTS There was less implant-position deviation for the 3D-printed group (mean ± SD: 56.37 ± 12.52 μm) than for the conventional group (71.94 ± 18.86 μm) (P = .014). No significant differences were found in angular deviation between the two groups (P > .05). Flexural strength results suggested that polylactic acid (112.7 ± 1.62 MPa) was stronger than poly(methyl methacrylate) (104.0 ± 2.17 MPa; P < .0001). The tensile bond strength of polylactic acid (0.07 ± 0.005 MPa) was higher than that of poly(methyl methacrylate) (0.03 ± 0.004 MPa; P < .0001). CONCLUSION The 3D-printing multi-implant impression technique could be an alternative to conventional impression techniques for complete arches.

With the more serious service environment, the new WC-Al2O3 as coatings are required to apply in high-temperature wear condition. Owing to the severe deterioration of WC-Al2O3 material in >500 °C, WC-Al2O3 composites with different content of Ni were prepared using vacuum hot-pressing sintering technology with the aim of improving its elevated temperature wear behavior. Wear experiments of WC-Al2O3-x%Ni against YG6 ball (WC-6Co) were conducted at 600 °C using a commercially made high-temperature ball-on-disk tribometer. The mechanical properties and oxidation wear behavior of Ni doped WC-Al2O3 composites were investigated. The phase and morphology of the sample surfaces were analyzed by XRD, EDS and SEM. The results show that the addition of Ni inhibited the decarburization of WC and ensured high mechanical properties. At elevated temperature, wear loss increased with loading. Without load, the mass loss decreased with the increase of Ni content. The minimum loss of WC-Al2O3 composite with 10%Ni is 3.1 mg, decreased by 72.7%. When the load increased to 15 N, the mass loss of WC-Al2O3 composite with 5%Ni is the minimum of 54.8 mg, decreased by 38.2%. On the whole, the addition of Ni is conducive to improving the resistance to oxidation wear. The wear mechanisms were dominated by oxidation wear and spalling of the tribolayer.

Background Complete digital workflow attracts more attention in implant dentistry. Objectives To explore the feasibility and short-term clinical results of immediate loading of multiple implants with fixed temporary bridges (2-4 teeth span) by complete digital workflow, and to evaluate the three-dimensional (3D) deviation of digital impression comparing with traditional impression method. Material and methods A total of 31 partial edentulous patients (16 females and 15 males) were recruited in this study. Digital impressions were taken immediately after implant placement, and implant-supported splinted temporary bridges were fabricated through a full digital approach (model free) and delivered within 24 hours. Final restorations were finished 4 months after surgery via traditional impression technique. Subjects were followed 1 year after treatment. 3D impression deviations were analyzed by comparing the digital and conventional impression methods. Time costs for the full digital approach were recorded. Implant survival rate, marginal bone levels were evaluated. Results All the recruited subjects finished this study. Seventy-four implants were surgically placed and immediately loaded with 34 temporary bridges fabricated through a full digital approach. Digital impression deviation compared with traditional impression method was 27.43 ± 13.47 μm. Time costs for chair side and laboratory were 32.55 ± 4.73 and 69.30 ± 10.87 minutes, respectively. Marginal bone alterations were -1.58 mm and -1.69 mm at the time of 4 and 12 months after surgery. The implants had a survival rate of 100% at the 1-year follow-up time. Conclusions Immediate loading of multiple implants in partial edentulous (2-4 teeth span) patients with full digital approach is clinically applicable. The 3D discrepancy between digital and traditional impression is within clinical acceptable range.

The characteristics of titanium (Ti) have been shown to influence dental implant fixation. Treatment of surfaces using the sandblasted, large-grit, acid-etched (SLA) method is widely used to provide effective osseointegration. However, the DNA methylation-associated mechanism by which SLA surface treatment affects osseointegration of human bone marrow mesenchymal stem cells (hBMSCs) remains elusive. Genome-wide methylation profiling of hBMSCs on SLA-treated and machined smooth Ti was performed using Illumina Infinium Methylation EPIC BeadChip at day 7 of osteogenic induction. In total, 2,846 CpG sites were differentially methylated in the SLA group compared with the machined group. Of these sites, 1,651 (covering 1,066 genes) were significantly hypermethylated and 1,195 (covering 775 genes) were significantly hypomethylated. Thirty significant enrichment pathways were observed, with Wnt signaling being the most significant. mRNA expression was identified by microarray and combined with DNA-methylation profiles. Thirty-seven genes displayed negative association between mRNA expression and DNA-methylation level, with the osteogenesis-related genes insulin-like growth factor 2 (IGF2) and carboxypeptidase X, M14 Family Member 2 (CPXM2) showing significant up-regulation and down-regulation, respectively. In summary, our results demonstrate differences between SLA-treated and machined surfaces in their effects on genome-wide DNA methylation and enrichment of osteogenic pathways in hBMSCs. We provide novel insights into genes and pathways affected by SLA treatment in hBMSCs at the molecular level.

In this study, the wear behaviors of an advanced WC-15%Al2O3 composite (WA15) were compared with a commercially available WC-8%Co cemented carbide (YG8). In order to evaluate and compare their anti-wear performance, the ball-on-flat dry sliding wear tests were conducted under different loads using a reciprocating tribometer. The cross sectional profiles of the wear scar on both materials were drawn using a surface profilometer. The volume loss and the wear rates were calculated depend on the cross sectional area (CSA) of the wear scar. The load-dependent wear results suggested that the anti-wear performance of WA15 was superior to YG8. The examination of worn surfaces from field emission scanning electron microscopy showed that the wear mechanisms of surface damage were mainly brittle fracture and plastic deformation.

Puerarin, which is a widely used in Traditional Chinese Medicine, was previously demonstrated to regulate the subsets of CD4+ lymphocytes in gunpowder smog-induced acute lung injury (ALI). However, the underlying mechanism remains largely unknown. Previous studies on autoimmune diseases have revealed that the renin-angiotensin system (RAS) and NF-κB participate in regulating the levels of CD4+ T lymphocytes. The aim of the present study was to further investigate the mechanisms underlying the protective effects of puerarin. Wistar rats were randomly divided into four groups as follows: Normal control, puerarin control, smoke inhalation injury and puerarin treatment plus smoke inhalation injury groups. The levels of angiotensin II (Ang II) in lung tissue and in the circulation, and the levels of interleukin (IL)-6, IL-1β, IL-17A and tumor necrosis factor (TNF)-α in the bronchoalveolar lavage fluid (BALF) were assayed using ELISA kits. The expression of Ang II type 1 receptor (AT1-R), angiotensin-converting enzyme (ACE) and ACE2 were examined by immunohistochemical analysis and western blotting. Phosphorylated (p-) NF-κB p65 and NF-κB inhibitor α (IκB-α) protein expression levels were also determined using western blotting. Puerarin treatment reduced the levels of inflammatory cytokines in the BALF. Furthermore, puerarin treatment significantly decreased the levels of Ang II, AT1-R and ACE, which were increased following smoke inhalation. Conversely, puerarin treatment upregulated the expression of ACE2, which was downregulated following smoke inhalation. Additionally, puerarin decreased the expression of p-NF-κB p65 and increased that of IkB-α. Thus, the antiinflammatory effects of puerarin were partly mediated via the RAS and via regulation of the NFĸB signaling pathway in rats with gunpowder smog-induced ALI.