Emergence Angle Research Articles

Anatomic Patterns of Distribution of the Renal Arteries' Origin from the Aorta

To characterize the variation of the renal arteries' origin from the aorta, through examination of computed-tomography angiographies (CTA) in a cohort of patients, and to evaluate any gender-related difference. CTA of the thoraco-abdominal district in patients with a non-dilated aorta (group A), patients with aortic aneurysm involving the origin of splanchnic and/or renal vessels (group B), and patients with abdominal aortic aneurysm (group C), were retrospectively analyzed. The diameter and angles of emergence (axial and cranio-caudals) of the renal arteries were measured, as well as their mutual distance, and the distance between the renal vessels and the superior mesenteric artery/the aortic bifurcation. Shapiro-Wilk, one-way ANOVA and bivariate Pearson's Correlation tests were performed as appropriate. A p-value <0.05 was considered statistically significant. Six-hundred CTA of patients (452 males) were examined, being 286 in group A, 119 in group B, and 195 in group C. When examining the whole population and also the subgroup of female patients, the clock position of the right renal artery (RRA) was the only parameter that followed a Gaussian distribution, and its ostium raised from the aorta with a mean axial angle of -61.5°+16.6°. There was a negative correlation between left renal artery (LRA) and RRA's coronal angle and aortic diameter at the same level, as well as between the LRA's clock position and the aortic diameter at the same level. The longitudinal distances between established landmarks and both renal arteries positively correlated to the aortic diameter. The LRA showed a high anatomic variability, both in males and in females. With the increase of the aortic diameters in the juxtarenal/infrarenal portion of the aorta, the renal vessels tended to have a more horizontal course in the coronal view, a more acute "clock-position" and longer longitudinal distances between their ostia and the aortic bifurcation.

Spatial arrangement of the whiskers of harbor seals (Phoca vitulina) compared to whisker arrangements of house mice (Mus musculus) and brown rats (Rattus norvegicus).

Whiskers (vibrissae) are important tactile sensors for most mammals. We introduce a novel approach to quantitatively compare 3D geometry of whisker arrays across species with different whisker numbers and arrangements, focusing on harbor seals (Phoca vitulina), house mice (Mus musculus) and Norway rats (Rattus norvegicus). Whiskers of all three species decrease in arclength and increase in curvature from caudal to rostral. They emerge from the face with elevation angles that vary linearly with dorsoventral position, and with curvature orientations that vary diagonally as linear combinations of dorsoventral and rostrocaudal positions. In seals, this diagonal varies linearly with horizontal emergence angles, and is orthogonal to the diagonal for rats and mice. This work provides the first evidence for common elements of whisker arrangements across species in different mammalian orders. Placing the equation-based whisker array on a CAD model of a seal head enables future mechanical studies of whisker-based sensing, including wake-tracking.

Wide Restorative Emergence Angle Increases Marginal Bone Loss and Impairs Integrity of the Junctional Epithelium of the Implant Supracrestal Complex: APreclinical Study.

To assess the influence of the emergence angle on marginal bone loss (MBL) and supracrestal soft tissue around dental implants. In six mongrel dogs, the mandibular premolars and molars were extracted. After 3 months of healing, four dental implants were placed in each hemimandible. The implants were randomly allocated to receive one of four customized healing abutments, each with a different value of the restorative emergence angle: 20°, 40°, 60° or 80°. Intra-oral radiographs were taken after placing the healing abutments and at 6, 9, 16 and 24 weeks of follow-up. Then, micro-CT and undecalcified histology and synchrotron were performed. MBL over time was analysed with generalized estimating equations (GEEs) and adjusted for baseline soft-tissue thickness. From implant placement to 24 weeks, GEE modelling showed that the MBL at mesial and distal sites consistently increased over time, indicating MBL in all groups (p < 0.001). The model indicated that MBL varied significantly across the different restorative angles (angle effect, p < 0.001), with 80° showing the greatest bone loss. Micro-CT, histology and synchrotron confirmed the corresponding trends and showed that wide restorative angles (60° and 80°) impaired the integrity of the junctional epithelium of the supracrestal tissue. A wide restorative angle increases MBL and impairs the integrity of the junctional epithelium of the implant supracrestal complex.

Alveolar ridge preservation and its impact on marginal bone level changes around dental implants: A retrospective, cohort comparative study.

This retrospective study compared the outcomes of implants placed in alveolar ridge preservation (ARP) treated sites with those in spontaneously healed (SH) sites. The study included patients presenting with one implant placed in an ARP-treated socket and one in an SH site. The primary outcome was the comparison of Marginal Bone Level Changes (MBLC). Statistical analysis was performed to identify factors influencing MBLC, including age, gender, smoking, parafunctional habits, and prosthetic emergence angle. Of these, 28 patients (23 females, 82.1%) were included in this analysis. Sockets in the SH group were classified as type I, whereas type II sockets were more common in the ARP group. The SH group exhibited significantly higher MBLC than the ARP group (p = 0.032), with values, respectively, of 1.00 [0.25; 1.62] and 0.40 [0.00; 1.00] mm. Among all evaluated parameters, the performance of ARP was the only factor significantly affecting MBLC (β = -0.72, SE: 0.32, p = 0.026). Age, gender, smoking, parafunctional habits, and prosthetic emergence angle did not significantly affect MBLC. The study shows the potential role of ARP in maintaining stable marginal bone levels around implants. In our sample, ARP significantly reduced MBLC compared with spontaneous healing, highlighting its possible impact in clinical practice for better peri-implant bone stability.

Association of Peri-Implant Mucosa Dimensions With Emergence Profile Angles of the Implant Prosthesis.

The primary aim of this cross-sectional study was to investigate the association between prosthesis design and peri-implant mucosa dimensions and morphology. The secondary aim was to investigate associations between mucosal dimensions and the presence of mucositis. Forty-seven patients with 103 posterior bone level implants underwent clinical and radiographic examination, including cone beam computer tomography and intraoral optical scanning. Three-dimensional models for each implant and peri-implant mucosa were constructed. Vertical mucosa height (TH), horizontal mucosa width at implant platform (TW), and 1.5 mm coronal of the platform (TW1.5), as well as mucosal emergence angle (MEA),deep angle (DA), and total contour angle (TA) were measured at six sites for each implant. There was a consistent correlation between peri-implant mucosa width and height (β = 0.217, p < 0.001), with the width consistently surpassing height by a factor of 1.4-2.1. All three angles (MEA, DA, TA) were negatively associated with mucosa height (p < 0.001), while DA was negatively associated with mucosa width (TW1.5) (p < 0.001, β = -0.02, 95% CI: -0.03, -0.01). There was a significant negative association between bleeding on probing (BoP) and mucosa width at platform (OR 0.903, 95% CI: 0.818-0.997, p = 0.043) and 1.5 coronal (OR 0.877,95% CI: 0.778-0.989, p = 0.033). Implants with less than half sites positive for BoP (0-2/6) had significantly higher mucosa height (OR 3.51, 95% CI: 1.72-7.14,p = 0.001). Prosthesis design can influence the dimensions of the peri-implant mucosa, with wider emergence profile angles associated with reduced peri-implant mucosa height. In particular, a wider deep angle is associated with reduced mucosa width in posterior sites. Reduced peri-implant mucosa height and width are associated with more signs of inflammation. Registered in Thai Clinical Trials Registry: http://www.thaiclinicaltrials.org/show/TCTR20220204002.

Impact of Interproximal Features on Marginal Bone Level Changes of Autograft, Allograft, and Xenograft after Functional Loading: A Retrospective Study

Abstract Aim: This study aims to investigate the marginal bone level changes (MBLCs) concerning interproximal features of posterior implant-supported single crowns using different bone grafts. Materials and Methods: This retrospective study included 27 patients requiring 46 dental implants using autograft, allograft, or xenograft between January 2007 and December 2016. MBLCs were assessed using digital periapical radiographs at 3 months (T1), 12–15 months (T2), and 21–24 months (T3) after prosthesis delivery. The influence of interproximal features, such as embrasure surface area, emergence angle, and horizontal distance to adjacent teeth/implants, was assessed. Secondarily, age, gender, diabetes and smoking, arch distribution, implant locations, implant characteristics, average gonial angle, antagonist type, clinical crown-to-fixture ratio, retention method, and nearby tooth/implant were considered. Wilcoxon signed-rank test, Mann–Whitney U tests, and Kruskal–Wallis tests were employed with statistical significance set at a P value of &lt;0.05. Results: The results revealed that mean MBLCs at T3–T1 were similar (autograft 0.5 ± 0.47 mm, allograft 0.51 ± 0.35 mm, and xenograft 0.57 ± 0.42 mm). There were significant increases in MBLCs associated with EA ≤ 30° in autograft (P = 0.04), and HD ≤ 3 mm in allograft (P = 0.03). Mesial/distal MBLCs showed no significant differences, except in cases with HD ≤ 3 mm in the distal area of autograft (P = 0.03). Regarding secondary factors, significant differences in MBLCs emerged between autograft and xenograft in the molar area (P = 0.03), and between premolar and molar areas within the xenograft group (P = 0.01). Conclusion: This study concludes that interproximal features, EA ≤ 30° and HD ≤ 3 mm, markedly influenced MBLCs for specific types of bone grafts. Furthermore, MBLCs exhibited a direct relationship with the posterior placement of dental implants.

Prosthetic design and choice of components for maintenance of optimal peri-implant health: a comprehensive review.

Current research has identified features of the prosthetic design with potential to significantly impact the long-term health of peri-implant tissues, while the choice of prosthetic components is also shown to be critical in an effort to reduce long-term complications of implant therapy. Overcontouring of the prosthesis emergence profile has been associated with marginal bone loss, recession and peri-implantitis, while the mucosal emergence angle is shown to have a strong association with peri-implant tissue inflammation. Further elements of interest include convexity/concavity of the restoration, the prosthetic connection and the different geometric configurations of junctions, as well as the peri-implant tissue dimensions. With regards to implant components, the choice between original and third-party-manufactured components might come with implications, as differences in material and microgeometry might impact precision of fit and overall performance, potentially leading to complications. Scrutiny of the specifications and manufacturing is essential when third-party-manufactured components are considered.The aim of this narrative review was to summarise the current evidence with regards to the restorative features of the implant prosthesis and also the selection of prosthetic components which can have implications for the long-term success of the implant therapy. Furthermore, the review aimed at interpretating current scientific evidence into meaningful strategies and recommendations to implement in clinical practice of implant dentistry.

Cross-sectional analysis comparing prefabricated titanium to individualized hybrid zirconia abutments for cemented zirconia based fixed dental prostheses: a critical concept assessment.

Despite the differences in material properties and shapes among the different types of prefabricated titanium (pTiA) and individualized hybrid zirconia abutments (ihZiA), the biological and clinical relevance of materials and construction features remains vague. Yet, individualized ihZiA are increasingly implemented into daily routine aiming to satisfy rising expectations. The objective was to compare these two types of abutments in fixed dental prostheses (FDP). This cross-sectional study examined 462 implants in 102 patients comparing pTiA (52 patients) to ihZiA (50 patients) for FDP. These different treatment regimens were evaluated in terms of peri-implant health, radiographic bone loss, and oral-health related quality of life (OH-QoL) with special consideration of abutment type and superstructure design. ihZiA showed significantly different design features than prefabricated pTiA, but the annual bone loss in both groups did not. Visible titanium in the esthetic zone negatively impacted OHIP 14 scores. The combination of an emergence angle (EA) of < 30° and a concave emergence profile (EP) as well as gingiva thickness (p = 0.002) at the time of the prosthetic restoration significantly improved the annual peri-implant bone loss, independently of the abutment type. ihZiA showed comparable results to pTiA. To optimize the long-term outcome, not just material alone but generating adequate soft tissue thickness, minimizing the EA, and applying a concave EP seem to be the most relevant factors. To improve OH-QoL, particular attention must be paid to the esthetic zone.

The effect of the interproximal contour of single external hexagon implant restorations on the prevalence of peri-implantitis: A retrospective study.

The objective of this retrospective study was to evaluate the effect of the interproximal contour of single external hexagon implant restorations on the prevalence of peri-implantitis. Records of 96 patients and 148 external hexagon (EH) implants with time in function ranging from 1 to 17 years were included in the study. The most recent clinical and radiographic data were collected from records and the prevalence of peri-implantitis was defined according to the 2017 World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions. Marginal bone level (MBL), emergence angle (EA), emergence profile (EP), and crown/implant platform horizontal ratio (CIHR) were obtained from periapical radiographs. Dichotomous variables at the patient- and implant level were compared with association tests. Mann-Whitney U-Test was performed to compare continuous quantitative values between the studied groups. Binomial logistic regression was conducted to identify risk indicators associated with the peri-implantitis event at the patient- and implant level, with the significance level set at 5% for all tests. Nineteen patients (19.2%) and 24 implants (16.2%) with a mean time in function of 5.0 ± 4.7 years were classified as having peri-implantitis. No statistically significant differences concerning gender, mean age, implant location in the jaw, or time in function were observed between patients with or without peri-implantitis (p > 0.05). Of 24 implants with peri-implantitis 10 (41.7%) displayed EA ≤ 30° (16.4%) while 14 (58.3%) presented EA > 30° with no statistical difference between the groups (p > 0.05). No statistically significant associations were identified between EA, EP, or CIHR and the prevalence of peri-implantitis. The findings seem to indicate that the EA, EP, and CIHR of single restorations over external hexagon implants are not associated with the presence of peri-implantitis. However, prospective studies with larger samples are required to better ascertain such an association in the long term.

Evaluation of the efficacy of inter-dental brush and dental floss for peri-implant mucositis: A crossover randomized clinical trial.

To evaluate the most effective method for mechanical inter-dental plaque removal between inter-dental brushes (IDB) and dental floss (DF), in addition to toothbrushing in patients affected by peri-implant mucositis (PIM); to identify possible factors related to the patient or to the single implant-supported element that could influence plaque accumulation and inflammation of peri-implant tissues. Forty patients with PIM were recruited. They were randomly assigned to two different groups depending on inter-dental device used (IDB or DF). At baseline (T0), interproximal area (IA), interproximal emergence angle of the implant crown (A°) and manual dexterity (evaluated with Purdue Pegboard) have been recorded. At 14 days (T1), the inter-dental cleaning devices have been inverted between groups. After 14 days (T2), the Plaque Index (PI) and Gingival Index (GI) have been recorded. A questionnaire has been submitted to a patient for the analysis of preferences at T0, T1 and T2. Both inter-dental cleaning devices were effective in reducing PI and GI in the inter-dental area after 14 days of use. GI reduction was influenced by manual dexterity of the dominant hand. No significant differences were found for PI and GI at the variation of IA and A°. IDB was the most effective method for inter-dental plaque removal in all subjects regardless of their manual dexterity. DF seems to be more effective than IDB only in subjects with good dexterity.

Experimental Investigation on the Influence of Observation Angle on the Spectral Characteristics of Minerals in the Visible-Near Infrared Range

The analysis of the factors affecting the spectral characteristics of rock minerals is the basis of improving the accuracy of quantitative inversion of spectral minerals. Hyperspectral remote sensing has advantages and development potential in the quantitative inversion of minerals, but it is limited by many constraints and influencing factors in the process of remote sensing recognition of rock and mineral spectral information. In practical application, satellite earth observation is affected by terrain fluctuation, which leads to some deviation of observation Angle. At the same time, vertical samples are often used in the experiment to reduce the spectral experimental error. Therefore, the spectral observation Angle plays an important role in determining the composition of rock and ore. In order to study the effect of different observation angles on the reflectance spectra of minerals, the spectral reflectance spectra were analyzed in the visible near-infrared (0.4-2.5μm) band to explore the variation rules. First, common quartz, orthoclase and plagioclase minerals were sliced and polished to make block samples with fixed roughness values. The incident Angle of light source was fixed, and the influence of different observation angles on the visible near-infrared spectral characteristics of minerals was analyzed by changing the Angle of emergence and azimuth. Secondly, through the qualitative and quantitative analysis of the results and the mechanism analysis, it can be concluded that the effect of zenith Angle on spectral reflectance is the same under different observation azimuth angles. The observed zenith Angle has a great influence on the spectral reflectance, which is reflected in the fact that the reflectance of mineral samples gradually increases with the increasing of the zenith Angle to reach the peak value within 30°~50°, and then gradually decreases. The spectral reflectance at 0°-360° azimuth is symmetrical, and the spectral reflectance is oscillatory, and the reflectance at 180° azimuth is the highest. The overall situation gradually increases from 0°-180° spectral reflectance, and gradually decreases from 180°-360° spectral reflectance. With the change of observation Angle, the peak and trough of the reflectance of the sample are basically located in the same band position. It is of great significance to realize the accurate division of rock mining area and to exploit mineral resources reasonably and efficiently.

Evaluation of drought-tolerant varieties based on root system architecture in cotton (Gossypium hirsutum L.)

BackgroundRoot system architecture (RSA) exhibits significant genetic variability and is closely associated with drought tolerance. However, the evaluation of drought-tolerant cotton cultivars based on RSA in the field conditions is still underexplored.ResultsSo, this study conducted a comprehensive analysis of drought tolerance based on physiological and morphological traits (i.e., aboveground and RSA, and yield) within a rain-out shelter, with two water treatments: well-watered (75 ± 5% soil relative water content) and drought stress (50 ± 5% soil relative water content). The results showed that principal component analysis identified six principal components, including highlighting the importance of root traits and canopy parameters in influencing drought tolerance. Moreover, the systematic cluster analysis was used to classify 80 cultivars into 5 categories, including drought-tolerant cultivars, relatively drought-tolerant cultivars, intermediate cultivars, relatively drought-sensitive cultivars, and drought-sensitive cultivars. Further validation of the drought tolerance index showed that the yield drought tolerance index and biomass drought tolerance index of the drought-tolerant cultivars were 8.97 and 5.05 times higher than those of the drought-sensitive cultivars, respectively.ConclusionsThe RSA of drought-tolerant cultivars was characterised by a significant increase in average length-all lateral roots, a significant decrease in average lateral root emergence angle and a moderate root/shoot ratio. In contrast, the drought-sensitive cultivars showed a significant decrease in average length-all lateral roots and a significant increase in both average lateral root emergence angle and root/shoot ratio. It is therefore more comprehensive and accurate to assess field crop drought tolerance by considering root performance.

The Impact of Implant Abutment Angle and Height on Peri-implant Tissue Health: Retrospective Analyses from a Randomized Controlled Clinical Trial.

To examine the influence of abutment emergence angle and abutment height on marginal peri-implant bone stability in patients not considered susceptible to peri-implantitis. Furthermore, it was analyzed whether titanium-base (Ti-base) abutments lead to wider abutment emergence angles compared to one-piece abutments. A total of 48 abutments (ie, 24 Ti-base and 24 one-piece abutments in 24 patients) were evaluated at abutment installation, after 1 year, and thereafter on a yearly basis for up to 5 years. Clinical and radiographic outcome variables were assessed. With regard to peri-implant marginal bone stability, only moderately negative, albeit significant, correlations were found on the mesial sides of the one-piece abutments after 4 and 5 years for an abutment emergence angle > 30 degrees. No statistically significant negative correlations were found for distances of ≤ 1.5 mm between the restoration margin and the crestal peri-implant bone level for either Ti-base or for one-piece abutments. Furthermore, abutments bonded to Ti-bases were not associated with larger emergence angles than one-piece abutments. For patients at low risk of developing peri-implantitis, it can be concluded that neither a larger abutment emergence angle (> 30 degrees) nor a distance of ≤ 1.5 mm between the restoration margin and the crestal peri-implant bone level are associated with marginal peri-implant bone loss. Furthermore, abutments bonded to Ti-bases are not associated with wider emergence angles than one-piece abutments.

Association between prosthesis contour and peri-implantitis in patients compliant with supportive periodontal therapy: A retrospective cohort study.

Poor contour of the implant restoration causes plaque accumulation and increases the risk of peri-implantitis. This study aimed to investigate whether the prosthodontic components of dental implants were associated with the prevalence of peri-implantitis. We enrolled 185 patients with 348 implants who underwent at least 1-year follow-up after the delivery of the prosthesis from February 2010 to January 2021. Demographic data of the patients and implants and the follow-up period were recorded. The emergence angle, type of cervical crown contour, and contour angle were analyzed using annual bite-wing radiographs. Peri-implantitis in this study was diagnosed if the peri-implant bone loss was greater than 2 mm between the bite-wing radiographs taken at baseline and the latest. Chi-square test, two-sample t-test, and multivariate logistic regression were used to investigate the differences and odds ratios between the peri-implantitis and non-peri-implantitis groups. The incidence of peri-implantitis was 14.9% during a follow-up period of 1509 days after the delivery of the prosthesis for at least 1-year. Based on the prevalence of non-peri-implantitis and after adjusting for confounding factors, the risk factors identified were bone types for implants (native bone vs. alveolar ridge preservation: adjusted odds ratio = 2.43, P = 0.04). Sex, arch, and guided bone regeneration vs. alveolar ridge preservation have the potential for a statistical difference. Compared with implants at alveolar ridge preservation sites, implants in the native bone were more prone to peri-implantitis. Further randomized controlled trials are required to determine these associations.

Relocating earthquakes in clusters based on variations in the intervals between their first P- and S-waves

The length of the interval between the first P- and S-waves is routinely used as a rough estimator of epicentral distance. We propose an algorithm for the relocation of earthquakes occurring in clusters, based on the simultaneous comparison of a large number of intervals. Variations in the intervals at each station are measured by cross-correlation between the respective portions of records directly and without a reference to any absolute times. In the current version of the algorithm, it is assumed that the size of the cluster is much smaller than the distance to the stations; the azimuths of the stations, as well as the angles of the emergence of the first P- and S-waves, are more or less accurately known for at least one (reference) earthquake; and the rays of the first waves lie in the vertical plane that contains the earthquake and the station. Under these assumptions, the relationship between the locations and the variations in the intervals becomes purely geometrical and linear, and the corresponding system can easily be solved. A series of synthetic experiments with different numbers and configurations of stations, levels of noise in the observed data, sparse data, and inaccuracies in azimuths and angles of emergence have demonstrated the stable and reliable performance of the algorithm and its potential applicability to real data. Due to the large number of constraints on each location, the algorithm can be used primarily in the case of small earthquakes or sparse networks when a large portion of data is missing. It can be used independently, to validate the locations determined by other methods, or be integrated into them, thereby improving their reliability by providing a large number of additional constraints.

Prosthesis Emergence Angle Influences Marginal Bone Level for External Connection Implants: A Cross-Sectional Study.

To retrospectively evaluate the influence of prosthetic features on marginal bone level changes around bone-level implants with an external hex connection. A total of 100 patients with 166 implants and cemented crowns were included. Demographic and clinical data were collected. Prosthetic features were radiographically evaluated, including emergence angle (EA), emergence profile (EP), crown-implant ratio (CIR), and abutment height. Marginal bone levels were measured on intraoral radiographs taken at baseline and after at least 1 year. The correlation between prosthetic features and marginal bone loss (MBL) was then investigated. The mean follow-up time was 43.94 months. Implant length varied between 5 and 13 mm. The mean height of the abutments used was 1.55 mm. EA measured an average 30.62 degrees (± 13.20) mesially and 29.45 degrees (± 13.07) distally. The CIR was 0.99 (± 0.26). The mean MBL was 0.19 mm on the mesial side and 0.20 mm on distal side of the implants. Significant positive associations emerged between MBL and implant length (P < .005) and with EA (P < .05). A convex profile of the crown was shown to be associated with a higher distal MBL (P = .025) compared to concave and straight profiles.

The effect of cement versus screw-retained implant positioning in the esthetic zone on emergence angle: A proof of principle.

Choosing between screw-retained and cement-retained restorations in the esthetic zone may have a significant implication on the restorative contour. This study analyzes the effect of facial-palatal implant positioning on the facial emergence angle of implant restorations in the maxillary anterior region. 133 maxillary anterior implant cases were captured with intraoral scans and used to create digital prosthetic designs. The facial emergence angle of the restoration and the depth of the implant were determined using images at the mid-facial cross-section. Simple logistic and linear regression models were used to analyze the interrelation between the emergence angle, depth, and retention methods. The average facial emergence angle for all restorations in this study was 34.4 degrees. A significant difference was found in emergence angle between screw-retained and cement-retained groups, with an average emergence angle of 37.3 degrees and 27.9 degrees, respectively. There is no difference in the mean depth between those two groups. There is a strong negative linear relationship between depth and emergence angle for the screw-retained group. Overall, implant positioning in the anterior maxilla has a significant influence on emergence angle. Facial emergence angle is significantly greater for implants in screw-retained position. This may be partially alleviated by deeper implant placement.

Simulation and experimental research on steady flow force compensation for a servo proportional valve

In the development of high-performance directly driven proportional directional valves, reducing the flow force of the spool is a crucial aspect due to its significant influence on the dynamic characteristics and power consumption of these valves. This paper presents a study on the steady-state flow force of a servo-proportional valve spool by employing a combined approach of numerical simulations and experiments. Additionally, a method is proposed to compensate for the steady-state flow force by modifying the shoulder inclination of the spool. The results demonstrate that modifying the shoulder angle of the spool alters the emergence angle, leading to a substantial reduction in the steady-state flow force acting on the spool. Notably, the compensation method has negligible impact on the through-flow capability of the servo-proportional valve.

Clinical effect of Nobel Biocare angulated screw channel crown compared with cement crown in the aesthetic area: A retrospective cohort study with a mean 32 months follow-up (range 12 to 70 months).

The objective of this study is to compare the clinical efficacy of angulated screw channel abutment applied in the anterior area with regular cemented crowns. Forty-eight patients were included and divided into two groups: the angulated screw channel group (ASC) and regular cemented group (RC) in this retrospective cohort study. The evaluation criteria included implant/restoration survival rate, keratinized mucosa width (KMW), bleeding on probing rate (BOP%), probing depth (PD), pink aesthetic score (PES), mechanical/biological complications, emergence angle (EA), the site of implant axis penetrate (SA), marginal bone loss (MBL), and buccal bone thickness (BBT) at 0 mm, 1 mm, 3 mm, 5 mm below the implant shoulder were evaluated in immediate postoperative (T0) and follow-up period (T1). This retrospective cohort study included a total of 48 patients, with a mean 32 months follow-up period range from 12 months to 70 months. The study did not find any cases of implant failure or restoration failure. EA was significantly wider in the RC group than ASC group (RC: 33.53° ± 8.36° vs ASC: 27.43° ± 8.08°, p = 0.016*). While the BOP% was statistically significant higher in the RC group than ASC group (RC: 28.35% ± 22.92% vs ASC: 13.18% ± 20.00%, p = 0.027*). No significant differences were observed in the other measurements of comparison. Within the limitations of the study, angulated screw channel (Nobel Biocare) crowns might allow the implant axis aim at incisal edge to reduce the emergence angle in the anterior area and benefit the soft-tissue during the 12-70 months follow-up period.

Implant retained prosthesis on a free fibula flap: A challenging procedure for prosthetic and soft tissue management

A 39-year-old woman who had undergone fibular flap reconstruction and simultaneous implant placement after the surgical removal of a cemento-ossifying fibroma was experiencing mild discomfort 3 years later and requested an implant-supported prosthesis to restore her edentulous left maxillary quadrant. Initially, an interim removable partial denture was provided and later duplicated with clear resin. The interim prosthesis identified the excessive thickness of the grafted cutaneous soft tissue and the inadequate emergence angle of the nonfunctioning implants. By using the interim prosthesis as a surgical guide, vestibuloplasty was performed to thin the peri-implant soft tissue and the excessive skin graft from the initial maxillofacial surgery. Concurrently, the emergence angle of the implant was corrected with angled multi-unit abutments. A tissue compression stent was then made and attached to the abutments to guide the soft tissue healing process. When the peri-implant soft tissue had stabilized, a definitive implant-supported prosthesis was provided.