Ridge Space Research Articles

Postcephalic segmentation and spines of the Siluro-Devonian odontopleurine trilobites Leonaspis Richter & Richter and Kettneraspis Prantl & Přibyl, with description of Bruthansovaspis gen. nov. from the Wenlock to Ludlow of the Prague Basin

Species of the odontopleurine trilobites Leonaspis Richter & Richter, 1917 and Kettneraspis Prantl & Přibyl, 1949 from the Silurian and the Devonian have been studied. Dorsal tubercle and spine patterns are highly variable and deemed of restricted use. The pygidial segmentation of Leonaspis is consistent among species in the development of a rudimentary inner pleural ridge or wide space between the pleural ridge and the axis. In Kettneraspis, an inner pleural ridge is never developed but the primitive condition is to have a space here. The formation of this ridge and an auxiliary interior border spine pair was arrested prematurely during ontogeny in species assigned to Kettneraspis at present. The type species of the monotypic Rupbachella Alberti, 2021 is regarded as a juvenile Leonaspis. Bruthansovaspis gen. nov. (type species: Acidaspis roemeri Barrande, 1852) is proposed for a Silurian clade of former Kettneraspis species from peri-Gondwana, that are principally distinct in lacking the combination of stunted anterior and macropleural posterior, thoracic segments synapomorphic of Kettneraspis and Leonaspis. The types of Bruthansovaspis roemeri, Bruthansovaspis dormitzeri (Hawle & Corda, 1847), Bruthansovaspis dumortieri (Hawle & Corda, 1847), Kettneraspis propinqua (Barrande, 1852), Kettneraspis lindackeri (Hawle & Corda, 1847) and Bruthansovaspis zenkeri (Hawle & Corda, 1847) (= B. dormitzeri) from the Silurian of the Barrandian, all of which had previously been lumped as dormitzeri, are figured and their classifications revisited. Exceptionally well-preserved odontopleurine material from the Devonian in the Tafilalt (southern Morocco) is described as Kettneraspis freitagi sp. nov. Leonaspis? strix Lütke, 1965 from the Devonian of the Harz Mountains is in need of revision; a previously tentatively assigned pygidium does not belong in that genus.

Equivalence study of the resin-dentine interface of internal tunnel restorations when using an enamel infiltrant resin with ethanol-wet dentine bonding

This preregistered ex vivo investigation examined the dentinal hybrid layer formation of a resinous infiltrant (Icon), with reference to both thickness (HLT) and homogeneity when combined with modified tunnel preparation (occlusal cavity only) and internal/external caries infiltration. The adhesives Syntac and Scotchbond MP were used as controls (Groups 1 and 3) or in combination with Icon (Groups 2 and 4). A split-tooth design using healthy third molars from 20 donors resulted in 20 prepared dentine cavities per experimental group. The cavity surfaces (n = 80) were etched (37% H3PO4), rinsed, and air-dried. Rewetting with ethanol was followed by application of the respective primers. After labeling with fluorescent dyes, either Syntac Adhesive/Heliobond or Scotchbond MP Adhesive was used alone or supplemented with Icon. HLT, as evaluated by scanning electron microscopy, did not significantly differ (P > 0.05), and confocal laser scanning microscopy revealed homogeneously mixed/polymerized resin-dentine interdiffusion zones in all groups. Icon can be successfully integrated into an ethanol-wet dentine bonding strategy, and will result in compact and homogeneous hybrid layers of comparable thickness considered equivalent to the non-Icon controls, thus allowing for preservation of the tooth’s marginal ridge and interdental space in the case of internal/external infiltration of proximal caries.

Разработка параметрической модели определения газового состава воздушной среды (аммиак, сероводород, углекислый газ) животноводческого помещения

Indoor climate parameters influence the productivity of animals and their physiological condition. Exceeding permissible concentrations of gases leads to animal diseases, loss of productivity, and the mortality of young cattle. Therefore, it is reasonable to predict the concentration of gas composition in the livestock houses. To determine and distribute harmful gases (ammonia, hydrogen sulphide, and carbon dioxide) in the livestock house, the authors performed the 3D modeling of a fragment of the farm in the SolidWorks 2020 software package. Parametric models of gas movement under different conditions were created and optimal measurement points of gas concentration in the livestock house were determined. The simulations made it possible to determine the direction of air flows and detect accumulations and clouds of gases. The maximum concentration of carbon dioxide was detected at 0.9m (an air speed of 0 m/sec) and at 1.3m (a speed of 0.75 m/sec). The highest concentration of hydrogen sulphide was found in the area bordering the ridge space (an air speed of 0 m/s) and at the level of 2.25 m (a speed of 2 m/s). The highest concentration of ammonia was observed under the roof and in the area under the ridge (an air speed of 2 m/s). It is recommended to install hydrogen sulphide and ammonia sensors under the ridge, while carbon dioxide, hydrogen sulphide and ammonia sensors – in the stall, carbon dioxide and hydrogen sulphide sensors – near the feed table. Concentrations should be measured at heights of 500, 1500, and 3000 mm. When the concentration of emitted gas increases and other conditions are equal, the concentration of gas in the cloud increases, but the structure of the cloud changes insignificantly. Parameter interrogation sensors should be installed in enclosed ventilated boxes in the same manner as in weather stations.

Edentulous ridge space closure after bone augmentation using different graft materials: A report of two cases

Abstract Post-extraction alveolar ridge resorption is a common sequela when missing mandibular molar spaces are not managed in a timely fashion. The situation becomes more complicated in patients who seek orthodontic treatment if closure of the edentulous space is the major objective in order to avoid prosthetic rehabilitation. In the present article, two cases are reported, in which different bone augmentation graft materials were used and treatment duration and post-orthodontic alveolar ridge characteristics were compared. A regional acceleratory phenomenon after the grafting procedure facilitated uneventful orthodontic space closure. The status of the investing alveolar bone was compared using post-treatment cone-beam computed tomography. Both autogenous bone graft and allograft ridge augmentation procedures aided in successful molar protraction through the resorbed mandibular alveolar ridge, as well as preventing periodontal attachment loss.

English

Removable prosthesis is probably one of the oldest types of dental therapy used to rehabilitate patients with complete or partial edentulousness. The main function of the edentulous alveolar ridge is to provide a major area of support for the dentures.1 Ill-fitting prosthesis leads to a condition where there is no longer adequate support of bone due to RRR. Hence, rehabilitation of such cases pose a clinical challenge, as there is a decreased denture foundation area for support, retention and stability.2 Residual ridge resorption (RRR) is the severe atrophy of alveolar bone underlying the mucoperiosteum. RRR affects the alveolar bone morphology, resulting in a decreased denture foundation area and increased inter-alveolar ridge space. The increase in inter-ridge distance provides a huge restorative space which results in a heavier complete denture due to greater volume of denture base material. This increase in restorative space amalgamates with the long lip length of the patient which gives rise to huge challenge to the success of the complete denture. Also, decreased denture foundation area increases the heaviness of the prosthesis and negatively affects the retention of the denture due to gravity.3 Various weight-reduction techniques have been used in the past using a rigid three-dimensional spacer, such as dental stone (Ackerman, 1955), cellophanewrapped asbestos, silicone putty during laboratory preparation to keep denture base content out of the intended hollow cavity of the prosthesis. The following case report describes a distinct lab technique for construction of hollow maxillary complete denture for a patient with severe RRR.

Ultrasonographic evaluation of edentulous crestal bone topography: A proof-of-principle retrospective study

Edentulous crestal bone ridge assessment, an essential task for planning of implant and bone regenerative procedures, is performed through radiographs. Ultrasonography, providing point of care and cross-sectional images without radiation, could be an adjunct for this purpose. The aim was to investigate the feasibility of ultrasound (US) in assessing bone ridge width (BRW) and crestal bone surface quality (CBSQ) compared with cone beam computed tomography (CBCT). Records of patients who were planned for implant placement in at least 1 healed edentulous ridge space with available CBCT and US images were included. The BRWs at 1, 2, and 3 mm from the crest were measured and compared. The CBSQ agreement evaluated using a 3-tier grading system was calculated. A total of 45 sites were included. The mean correlation of BRW was 0.97. The mean BRW differences ranged from 0.048 mm (95% confidence interval, -0.69 to 0.78 mm) at the 1-mm level to 0.18 mm (95% confidence interval, -0.92 to 1.3 mm) at the 3-mm level. There was a 91% agreement in CBSQ between the 2 methods. Preliminary data with a limited clinical sample size suggested that US is feasible in evaluating crestal BRW and surface quality assessment compared with CBCT.

Validity and reliability of intraoral conventional tracer and intraoral digital tracer in different positions for recording horizontal jaw relation in edentulous patients.

Aim:The purpose of the study is to evaluate and compare the horizontal mandibular positions recorded between intraoral conventional tracer and intraoral digital tracer in upright and supine position.Materials and Methods:Twenty-four edentulous patients with well-formed ridge and adequate interarch distance space were selected. MATLAB software was assimilated with intraoral digital tracer and was utilized in the study for recording the horizontal movements of the mandible, i.e., gothic arch tracing by intraoral digital tracer and was observed on a laptop with the help of MATLAB Software. For each subject, multiple mandibular readings were recorded and analyzed through software, and similar readings were recorded with conventional intraoral tracers. The comparison between intraoral conventional tracer and intraoral digital tracer was done to assess the reliability. Moreover, the consistency of recording horizontal mandibular position was also compared between upright and supine position.Results:The data were procured and utilized in comparison for different positions revealed statistically significant difference by using Student's Paired t-test. The test resulted in supine position better compared to upright position (P = 0.0001). The association between supine position with upright position was calculated using Fischer's exact test, and it was also found to be statistically significant (P = 0.002). The Pearson's Correlation analysis was performed to check the agreement between upright and supine position and very weak downhill correlation (r2= −0.130) was observed between the two variables.Conclusion:On evaluation and comparison of horizontal mandibular position, it was found that the intraoral digital tracing technique is more valid compared to conventional intraoral tracer technique. It was also observed that the consistency of reproducibility in recording horizontal mandibular position in supine position is significantly higher than upright position.

Impact of Plant Spacing and Weed Control Treatments on Yield, Quality of Soybean (Glycine Max L.) and Associated Weeds Characters under Middle Egypt Conditions

The present study was carried out on soybean var. Giza 111 atthe Experimental Farm of Faculty of Agriculture, El-Minia University during the summer seasons of 2015 and 2016, to study the impact of plant spacing and weed control treatments on weed control, yield and quality of soybean. The treatments include rows and plant spacing (density) as P1: 60×4cm (175000 plant fed-1), P2: 60×5cm (140000 plant fed-1), P3: 70×4cm (150000 plant fed-1) and P4: 70 × 5cm (120000 plant fed-1) and 10 weed control treatments (W1: Gesagard 50% FW at 1 L fed-1,W2: Fusilade super 12.5%EC at 1 L fed-1, W3: Gesagard 50%FW+ Fusilade super 12.5% EC,W4:Stomp 50%EC at 1.7 L fed-1,W5: Stomp 50%EC + Select-super 12.5% EC at 1 L fed-1, W6: Select-super 12.5%EC, W7: Stomp 12.5%EC+ one hand hoeing, W8: hand hoeing twice, W9: unweeded check and W10: weed free for whole seasons. This study was carried out in a strip-plot design with three replications. Results showed that increasing of soybean plant density by sowing in the narrow ridge (60 cm) and plant space (4 cm between hills) caused a significant reduction in fresh and dry weight of weeds at 60 days after planting (DAP), compared to wider plant spacing in both seasons. The narrow spacing 60×4 cm led to a reduction in dry weight of total weeds by 26.62 % and 22.90 % and increased soybean seed yield by 5.31% and 4.92% in 2015 and 2016 seasons, respectively. All weed control practices reduced the fresh and dry weight of total weeds, compared to the unweeded check in both seasons. Yield of seeds in unweeded check plots was decreased were about 43.18 and 42.69% due to about 3.5 and 3.3 ton fed-1 fresh weight of total weeds in 2015 and 2016 seasons, respectively, compared to weed free for whole season. Protein and oil% of soybean seeds were decreased by (10.56 and 10.60%) and (18.23 and 18.05%) in 1st and 2nd seasons, respectively due to the weed interference. The interaction effect between plant spacing, 60×4 cm (P1) and weed free followed plant spacing P1 and weed control by Stomp 50%EC + one hand hoeing (W7) gave the best weed control efficiency (WCE) 78.9 and 81.0% in 2015 and 2016 seasons, respectively as well as superior in seed yield of soybean and net return.

Effect of Intercropping Three Faba Bean Varieties with Sugar Beet Plants on Piercing Sucking Insect Pests and Associated Natural Enemies Under Ridge Space and Seedling Rates in Relation Crop Yield.

Field experiment were conducted at Gemmiza Agricultural research Station, El Gharbia Governorate, Egypt, in 2014/2015and 2015/2016 seasons to study the effect of intercropping faba bean (Vicia faba L.) with sugar beet (Beta vulgaris L.) at different ridge width 60, 90 and 120 cm and seedling rats on the population densities of piercing sucking insect pests and their effect on the productivity of both crops and estimate the economic return. Results was indicated that the intercropping of broad bean at 60cm ridge space with sugar beet harbored the lowest piercing sucking pest infestations. However, Giza 3 improve at 120 cm ridge space was received the highest infestation. On the other hand, Giza 716 was infested by highest infestation at 37.5% seed rates when intercropping with sugar beet. The lost infestation was recorded on sugar beet + Giza 3 improve with 12.5% seed rates. Statistical analysis was showed the intercropping faba been with sugar beet on different ridge width significantly affected on sugar beet yield and yield components. Increasing sugar beet root length and purity % by planting on 60 cm ridge width, compared to 90 and 120 cm. On the other hand, root diameter, root fresh weight, top fresh weight, root yield/fed, top yield/fed T.S.S and sucrose were significantly increased by increasing ridge width from 60 to 120 cm. The effect of ridge width on faba bean traits revealed that increasing ridge width from 60 cm to 120 cm reduced plant height only of faba bean. On the other hand, number of pods/ plant, seeds/plant, weight of 100 seeds and grain yield /fed ardab were increased by increasing ridge width from 60 cm to 120 cm , while Protein content% was not affected by ridge width. Increasing seeding rates from 12.5 % to 37.5 % increased plant height and straw yield/ fed. The differences among faba bean varieties indicated that only plant height and number of seeds/ plant were affected by faba bean varieties. On the other hand, all the other characters were affected by faba bean varieties. highest values of Land equivalent ratio (LER), Farmer,s benefit (Total return of intercropping culture , Net profit fed-1 ) and Monetary advantage index (MAI) compared with other treatments . It could be concluded that intercropping 100 % sugar beet + 37.5 % faba bean Giza 3 improve cultivar (52500 plants / fed) on ridge width 120 cm gave the greatest values for all treatments which gave the maximum yield benefits and least competition between component crops compared with other treatments .

Implant-abutment interface: A comparison of the ultimate force to failure among narrow-diameter implant systems

Limited available alveolar ridge bone and space deficiencies are some of the challenging scenarios that have led many dental implant manufacturers to develop narrow-diameter implants of various designs. Clinicians may have concerns about the durability and function of the narrow-diameter implants. The purpose of this study was to explore and compare the ultimate failure resistance of the smallest diameter of the 2-stage type implant provided by 5 commonly used dental implant systems. Thirty implants, Astra OsseoSpeed 3.0 mm and 3.5 mm, Straumann Bone Level 3.3 mm, Zimmer Tapered Screw-Vent 3.7 mm, Full Osseotite Certain 3.25 mm, and NobelSpeedy Replace 3.5 mm, 5 of each type, were tested in this study. A rigid clamp was used to hold the implants at a 30-degree angle to a static load vector. The load continued until the specimen broke or obviously deformed. Peak loads were recorded at that point for all the studied implant systems. Student t test and 1-way ANOVA were used to compare the mean peak load values (α=.05). The mean fracture/deformation peak load values were 367.20 N ± 98.05 for Astra OsseoSpeed 3.0 mm; 568.80 N ± 85.24 for Astra OsseoSpeed 3.5 mm; 679.00 N ± 81.09 for Full Osseotite Certain 3.25 mm; 553.4 N ± 56.96 for NobelSpeedy Replace 3.5 mm; 802.80 N ± 134.50 for Zimmer Tapered Screw-Vent 3.7 mm; and 576.20 N ± 71.45 for Straumann Bone Level 3.3 mm. Generally, a higher load was required to cause failure in implants with larger diameters than in narrower-diameter implants, and more force was necessary to cause failure in Ti6Al4V alloy implants than in commercially pure titanium implants. With regard to implant diameter and ultimate failure strength, Osseotite Certain 3.25 mm was considered to be more advantageous in comparison with the other implants tested.

칼날형 마모시험기를 이용한 C/B충전 NR 배합고무의 마모거동

칼날형 마모 마찰 시험기를 이용하여 NR배합고무의 마모 거동을 조사하였다. 온도, 하중, 그리고 회전속도를 변화시켜 마모속도에 미치는 영향과 열화된 배합고무의 마모 현상에 대해 평가하였다. 시편의 회전속도와 수직 하중이 증가할수록 마모속도가 증가하였다. 실험온도가 증가할수록 마찰계수가 감소하였고, 마모속도도 감소하였다. 마찰에너지와 마모속도 사이에 Power-Law 관계를 나타냈으며 마모속도는 열화에 의해 급격히 증가하였다. 시편의 마모패턴은 마모조건에 의해 영향을 받았으며 특히 수직 하중을 변화시켰을 때 마모융기(ridge)간격에 큰 변화를 보였다. 배합고무의 마모속도를 결정하는데 간헐적 마모손실 무게측정 대신 칼날형 마모시험기를 이용한 연속적인 마모이동거리측정으로 대체할 수 있음을 확인하였다. Friction and wear behaviors of natural rubber(NR) compounds were investigated using a blade-type abrader. The effects of temperature, normal load, and rotation speed on wear rate were studied, and wear behaviors of deteriorated compounds were also evaluated. As the rotation speed of specimen and the normal load to specimen increased, the wear rate increased. However, as the experimental temperature increased, the frictional coefficient decreased and the wear rate decreased accordingly. It was found from the wear studies that a power-law relation works between the frictional work input and the wear rate. It was observed that the wear rate dramatically increased by the degradation of the rubber specimen. The wear pattern was developed and the bigger ridge space of the pattern was observed usually in the higher normal load applied. In determining the wear rate of rubber compound, the continuous measurements of wear distance using the blade-type abrader could be successfully used instead of intermittent measurements of wear-loss weight.

Lost salt technique for severely resorbed alveolar ridges: An innovative approach

The success of a complete denture relies on the principles of retention, stability and support. The prosthodontist skill lies in applying these principles efficiently in critical situations. Severely resorbed maxillary edentulous ridges that are narrow and constricted with increased inter ridge space provide decreased support, retention and stability. The consequent weight of the processed denture only compromises them further. This article describes a case report of an edentulous patient with resorbed ridges where a simplified technique of fabricating a hollow maxillary complete denture using lost salt technique was used for preservation of denture bearing areas. The hollowing of the denture reduces the weight of the denture, thereby enhancing stability and retention, reducing the further resorption of the jaws.

Light weight maxillary complete denture: A case report using a simplified technique with thermocol

The success of a complete denture relies on the principles of retention, stability and support. The prosthodontist's skill lies in applying these principles efficiently in critical situations. Severely resorbed maxillary edentulous ridges that are narrow and constricted with increased inter ridge space provide decreased support, retention and stability. The consequent weight of the processed denture only compromises them further. This article describes a case report of an edentulous patient with resorbed ridges where a simplified technique of fabricating a light weight maxillary complete denture was used for preservation of denture bearing areas.

Development and distribution of geohazards triggered by the 5.12 Wenchuan Earthquake in China

As the Wenchuan Earthquake was of high magnitude and shallow seismic focus, it caused great damage and serious geohazards. By the field investigation and the interpretation of remote-sensing information after the earthquake and by using means of GIS technology, the distribution of geohazards triggered by the earthquake are analyzed and the conclusions are as follows: (1) The earthquake geohazards showed the feature of zonal distribution along the earthquake fault zone and linear distribution along the rivers; (2) the distribution of earthquake geohazards had a marked hanging wall effect, for the development density of geohazards in the hanging wall of earthquake fault zone was obviously higher than that in the foot wall and the width of strong development zone in the hanging wall was about 10 km; (3) the topographical slope was a main factor which controlled the development of earthquake geohazards and a vast majority of hazards were distributed on the slopes of 20° to 50°; (4) the earthquake geohazards had a corresponding relationship with the elevation and micro-landform, for most hazards happened in the river valleys and canyon sections below the elevation of 1500 to 2000 m, particularly in the upper segment of canyon sections (namely, the turning point from the dale to the canyon). Thin ridge, isolated or full-face space mountains were most sensitive to the seismic wave, and had a striking amplifying effect. In these areas, collapses and landslides were most likely to develop; (5) the study also showed that different lithologies determined the types of geohazards, and usually, landslides occurred in soft rocks, while collapses occurred in hard rocks.

Agricultural practices in relation to yield and quality of sugar beet: Yield and yield components

The root number/feddan of the two seasons sown with planter showed distinct advantage compared to the manual sowing. The narrower the ridge space (15 cm) the higher, the root numbers/fed. (30716 and 31175 in both seasons, respectively). The differences between soaking treatments with respect to their effect on root number/feddan were not significance in the second seasons. Sowing sugar beet mechanically attained additional increment in root yield over those under the traditional method (sowing manually) amounted by 8.52 % and 25.08 % in the 1st and 2nd seasons, respectively. Soaking sugar beet seeds befor sowing significantly surpassed the dried method with respect to root yield. There was a positive response in the values of root yield due to ridge space from 15 cm to 20 cm produced on increment in root yield amounted by 4.79 % in the 1st season corresponding 4.94 % in the 2nd season. There was no clear cut trend due to the effect of sowing method on richness per cent. The values of richness per cent reflected an opposite response in the two seasons, where the narrow ridge space (15 cm) recorded the higher values of this trait in the first season. On the contrary the wider ridge space (20 cm) attained the highest value of this trait in the 2nd season. Sowing sugar beet seeds by using soaked seeds attained relative increments in richness per cent in the 1st season. On the contrary, sowing sugar beet seeds using the dried seeds in the 2nd season appeared significant increase in this trait. There are general tendencies toward increasing the sugar yield/fed by using planter technique for sowing sugar beet seeds. The wider, ridge space (20 cm), gave the higher sugar yield/fed (4.19 and 4.14 ton/fed.). Sowing sugar beet crop by the soaked seeds attained and significant increase in sugar yield in the 2nd season.

Classical dynamics of two-electron atoms at zero energy

We give a complete description of the classical dynamics of two electrons in the Coulomb potential of a positively charged nucleus for total energy E=0 and angular momentum L=0. The effectively four-dimensional phase space can be divided into partitions spanned by the stable and unstable manifold of the Wannier ridge space. We identify a further approximate symmetry by choosing an appropriate Poincaré surface of section in this dynamical system. In addition, a dividing surface between the dynamics influenced by the two collinear spaces, the stable Zee space and the strongly chaotic eZe space can be identified. We discuss potential extensions of the binary symbolic dynamics found in collinear two-electron atoms to the noncollinear parts of the phase space for E< or =0.

Laws of articulation

An analysis of the laws of articulation as developed by Hanau indicates the necessity for re-evaluation of his concepts. It has been shown that the use of the height of the cusp as an active factor in producing a balanced articulation is not correct. Hanau should have emphasized the role played by the inclination of the effective cusp inclines. The use of the factor plane of orientation is misleading and needlessly complicating. The location of the plane of orientation is highly variable within the available ridge space and should not be limited to a standardized height. The use of the compensating curve as an active factor in the laws of articulation is not necessary or desirable. The formation of the compensating curve is always the result of the harmonious interplay between the incisal guide angle, the condylar guidance, and the cuspal angulation.