Inter-ridge Distance Research Articles

The relationship between body size and stridulatory sound production in loricariid catfishesa).

Sound production capabilities and characteristics in Loricariidae, the largest catfish family, have not been well examined. Sounds produced by three loricariid catfish species, Otocinclus affinis, Pterygoplichthys gibbiceps, and Pterygoplichthys pardalis, were recorded. Each of these species produces pulses via pectoral-fin spine stridulation by rubbing the ridged condyle of the dorsal process of the pectoral-fin spine base against a matching groove-like socket in the pectoral girdle. Light and scanning electron microscopy were used to examine the dorsal process of the pectoral-fin spines of these species. Mean distances between dorsal process ridges of O. affinis, P. gibbiceps, and P. pardalis were 53, 161, and 329 μm, respectively. Stridulation sounds occurred during either abduction (type A) or adduction (type B). O. affinis produced sounds through adduction only and P. pardalis through abduction only, whereas P. gibbiceps often produced pulse trains alternating between abduction and adduction. In these species, dominant frequency was an inverse function of sound duration, fish total length, and inter-ridge distance on the dorsal process of the pectoral-fin spine and sound duration increased with fish total length. While stridulation sounds are used in many behavioral contexts in catfishes, the functional significance of sound production in Loricariidae is currently unknown.

Prosthetic management of resorbed ridges through fabrication of hollow denture using three-dimensional glycerin spacer and neutral zone technique

Residual ridge resorption leads to diminished retention, support, and stability of the prosthesis due to decrease in the denture supporting areas, decreased denture space, and increased leverage due to increase inter-ridge distance. The prosthetic rehabilitation of the severely resorbed ridges needs modification for the fabrication of a stable prosthesis. This clinical report describes the prosthetic management of resorbed ridges using modified impression technique, neutral zone technique, external impressions, and fabrication of a hollow denture using three-dimensional glycerin spacer to enhance the retention and stability of the prosthesis.

Compression-induced buckling of thin films bonded to viscous substrates: Uniform wrinkles vs localized ridges

We examine the buckling of a thin elastic film bonded to a much thicker viscous substrate undergoing compression at a fixed rate. Experiments show two distinct buckling modes. At high rate of compression or at large liquid thickness, the buckles take on the form of approximately-sinusoidal wrinkles. At low rate of compression or at small liquid thickness, the buckles are highly localized into tall ridges separated nearly flat regions. Ridge growth is accompanied by lateral motion of the film in the near-ridge region, and the liquid in that region undergoes severe shear flow. Such ridge formation is entirely distinct from other examples of curvature localization such as fold localization of films on liquids in static equilibrium or ridge formation of films bonded to hyperelastic substrates. We quantify how the two lengthscales that arise from the buckling process, the wrinkle amplitude and the interridge distance, depend on compression rate and liquid thickness. We show that wrinkles formed during compression can also transform into ridges under quiescent conditions which suggests that buckle localization reduces bending energy of the film. We speculate that ridge localization appears due to a competition between two effects: a buckle mode with a few well-spaced ridges offers a lower energy state than uniform wrinkles, but wrinkles can develop faster because they require the viscous fluid to move over shorter distances.

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.

Prosthodontic rehabilitation of compromised upper and lower residual alveolar ridges: A case report

Residual ridge resorption is the reduction in size of the bony ridge under the mucoperiosteum. Obtaining retention and stability in a severely resorbed ridges using a conventional technique is a tedious task. The resorption occurs at a faster rate in mandibular arch as compared to the maxillary arch. In order to have a favorable prognosis for the denture therapy, impression technique selected should be based on the present state of the basal tissue support for mandible. In this article neutral zone concept was incorporated in to impression making in an effort to achieve successful mandibular complete denture. The anterior region of maxilla is the most affected area in edentulous patients. Complete denture wearers with flabby ridges may face a number of difficulties, of which major complaints would be pain, compromised stability, support, and retention and an ill-fitting denture. Special impressions often involve window technique for static impression of flabby area, which present multiple challenges. This article presents a case report of modified widow impression technique for maxillary anterior flabby tissues along with a hollow maxillary complete denture in a patient with resorbed maxillary and mandibular ridges with increased interridge distance to reduce the weight of the prosthesis and thereby enhances the retention.

The roles of lower- and higher-order surface statistics in tactile texture perception.

Humans can haptically discriminate surface textures when there is a significant difference in the statistics of the surface profile. Previous studies on tactile texture discrimination have emphasized the perceptual effects of lower-order statistical features such as carving depth, inter-ridge distance, and anisotropy, which can be characterized by local amplitude spectra or spatial-frequency/orientation subband histograms. However, the real-world surfaces we encounter in everyday life also differ in the higher-order statistics, such as statistics about correlations of nearby spatial-frequencies/orientations. For another modality, vision, the human brain has the ability to use the textural differences in both higher- and lower-order image statistics. In this work, we examined whether the haptic texture perception can use higher-order surface statistics as visual texture perception does, by three-dimensional (3-D)-printing textured surfaces transcribed from different "photos" of natural scenes such as stones and leaves. Even though the maximum carving depth was well above the haptic detection threshold, some texture pairs were hard to discriminate. Specifically, those texture pairs with similar amplitude spectra were difficult to discriminate, which suggests that the lower-order statistics have the dominant effect on tactile texture discrimination. To directly test the poor sensitivity of the tactile texture perception to higher-order surface statistics, we matched the lower-order statistics across different textures using a texture synthesis algorithm and found that haptic discrimination of the matched textures was nearly impossible unless the stimuli contained salient local features. We found no evidence for the ability of the human tactile system to use higher-order surface statistics for texture discrimination.NEW & NOTEWORTHY Humans can discriminate subtle spatial patterns differences in the surrounding world through their hands, but the underlying computation remains poorly understood. Here, we 3-D-printed textured surfaces and analyzed the tactile discrimination performance regarding the sensitivity to surface statistics. The results suggest that observers have sensitivity to lower-order statistics whereas not to higher-order statistics. That is, touch differs from vision not only in spatiotemporal resolution but also in (in)sensitivity to high-level surface statistics.

Mandibular implant supported overdenture for an edentulous patient with less interridge distance using locator attachment- A case report

Satisfying the edentulous patients with conventional complete denture has nowadays become a challenge to the prosthdontist as the patients have problems adapting to their denture especially in mandibular arch due to decreased retention, stability and difficulty in mastication. So a better treatment option for those patients is attachment retained implant supported overdenture. Overdenture helps in increasing the proprioception, retention, stability, comfort and confidence of the patient and decreasing the residual ridge resorption. Commonly used attachments used to retain implant supported overdenture are stud, bar, magnetic and telescopic attachment. This article presents a case report of implant supported overdenture for an edentulous patient with less interridge distance retained using locator attachment. Keywords: Implant supported overdenture, Locator attachment, Less interridge distance.

A DEVICEFUL APPROACH OF MANAGING HOLLOW MAXILLARY COMPLETE DENTURE

Retention, stability and support are the most fundamental and basic principles on which the success of an entire denture relies on. However this factor is often compromised in cases of resorption. Residual ridge resorption is the reduction in size of the bony ridge under the mucoperiosteum. The rate of resorption in mandibular arch is at an increased rate as compared to the maxillary arch; but severely atrophic maxillae with large inter-ridge distance often pose a clinical challenge during fabrication of a successful maxillary complete denture because of the increased weight of the denture, retention is compromised. The present article describes a case of a completely edentulous patient who was successfully rehabilitated with a hollow denture where a simple and deviceful technique of fabricating a light-weight maxillary denture. The present article describes a case of a completely edentulous patient who was successfully rehabilitated with a hollow denture where a simple and deviceful technique of fabricating a light-weight maxillary denture was used using the hollow tubing of salivary ejector apparatus to bring the uniform hollowness.

Fabrication of hollow maxillary complete denture: A simplified technique

Residual ridge resorption is the reduction in size of the bony ridge under the mucoperiosteum. Prosthetic rehabilitation of severely atrophic ridges has always been difficult for the clinician due to decreased retention, stability and support. Because of such severe resorption the restorative space between maxillary and mandibular residual ridges is increased. Rehabilitation in such cases may result in increased height and weight of the prosthesis further compromising its retention and stability. This in turn overloads the underlying hard and soft tissues that cause further ridge resorption so, in order to keep down this undesirable sequence, the weight of the prosthesis needs to be reduced which can be achieved by making hollow prosthesis. This article describes a simple technique of fabricating a hollow maxillary complete denture. Keywords: Hollow denture, Inter-ridge distance, Simple technique

Fingerprint frequency normalisation and enhancement using two‐dimensional short‐time Fourier transform analysis

A fingerprint image with non‐uniform ridge frequencies can be considered as a two‐dimensional dynamic signal. A non‐uniform stress on the sensing area applied during fingerprint acquisition may result in a non‐linear distortion that disturbs the local frequency of ridges adversely affecting the matching performance. This study presents a new approach based on Short time Fourier transform analysis and local adaptive contextual filtering for frequency distortion removal and enhancement. In the proposed approach, the fingerprint image is divided into sub‐images to determine local dominant frequency and orientation. Gaussian Directional band pass filtering is then adaptively applied in frequency domain. These filtered sub‐images are then combined in spatial domain using a novel technique to obtain the enhanced fingerprint image of high ridge quality and uniform inter‐ridge distance. Simulation results show the efficacy of the proposed enhancement technique as compared to other well‐known contextual filtering based enhancement techniques reported in the literature.

An alternative technique for hollowing maxillary complete denture.

Extreme resorption of edentulous maxilla may cause difficulty during fabrication of a maxillary complete denture. Increased inter-ridge distance often creates a clinical problem due to heavy-weighted maxillary prosthesis. This article elaborates an alternative approach for hollowing a maxillary complete denture. It utilizes a clear template of the trial denture facilitating the creation of a gelatin cavity form. This hollowing ensures the even thickness of both denture base resins for structural integrity and reduces the heaviness of the denture.

Fingerprint classification and building a gender prediction model using random forest algorithm

The popularity of fingerprints as the means of an individual's identification has increased, and has resulted in a drastic increase in the size of fingerprint datasets. Every fingerprint can be classified based on their patterns. This can be done with the help of a classification system, which also helps to reduce the search and space complexity of the identification algorithm. Random Forest RF algorithm is an ensemble-learning method proved to be very effective in the field of bioinformatics. The system proposed in this paper applied the RF algorithm to help classify the fingerprints, and found that it produces highly accurate results in reasonable time. In addition, different features of the fingerprints such as number of ridge-endings and bifurcations, number of cores and deltas and average inter-ridge distance, were used to build a gender prediction model, which was found to be reasonably accurate.

Rehabilitation of severely resorbed maxilla with a hollow maxillary complete denture

Rehabilitation of severely resorbed maxilla poses a clinical challenge for fabrication of a successful maxillary complete denture. The increased interridge distance often results in a heavy maxillary complete denture that further reduces the retention and stability of the denture. This case report describes the rehabilitation of an edentulous patient with resorbed maxillary and mandibular ridges and an increased interridge distance by hollow maxillary complete denture so as to reduce the weight of the denture which enhances the retention and stability of the denture. DOI: http://dx.doi.org/10.3126/hren.v11i3.9655 Health Renaissance 2013;11(3):281-283

Rehabilitation of atrophic maxilla with a hollow maxillary complete denture: A case report

Residual ridge resorption is the reduction in size of the bony ridge under the mucoperiosteum. The rate of resorption is more in mandibular arch as compared to the maxillary arch; but severely atrophic maxillae with large inter-ridge distance often pose a clinical challenge during fabrication of complete denture due to decreased support, retention and stability. This clinical report describes successful rehabilitation of a completely edentulous patient with atrophic ridges using hollow maxillary complete denture.

Stridulatory organ and distress call in males and females of a small velvet ant (Hymenoptera: Mutillidae)

Stridulation patterns and stridulatory organ were rarely investigated in the parasitoid family Mutillidae, and data still lack for any sex or species in many subfamilies. We described the morphology of stridulatory organ and the distress call of Myrmilla capitata (Myrmillinae), a small mutillid wasp in which both sexes are apterous. As in other mutillids, the stridulation is produced by rubbing a scraper on the gaster tergite II against a file on gaster tergite III and consists of sequences of pulse trains organized in two subunits (disyllabic chirps) characterized by pulses with opposite phase. Overall, sexes differed in few morphological and acoustical traits. In particular, females had wider and longer files (due to the larger tergite III), smaller ridge thickness, greater inter-ridge distance and produced sound with lower maximum frequencies. This is in accordance to the fact that individuals with wider files, and files with thicker and more separated ridges, tend to emit sounds reaching lower frequencies. Both sexes, on average, seemed to “use” about 50% of the ridges while stridulating, and the file is moved against the scraper with an average speed of about 6 mm/s. Syllable duration and pulse rate (number of pulses/s) were also affected by some morphological traits of the file. Thus, intra-specific variation in the morphology of the stridulatory organ affects stridulation features in this small velvet ant with relatively weak sexual dimorphism.

A Framework of Fingerprint Scaling

Fingerprint scaling refers to the adjustment of fingerprint images to solve the problem of sensor interoperability. In this paper, we present an innovative framework of fingerprint scaling with minimum modification to existing systems. For the purpose of facilitating system configuration, we have developed a series of scaling methods, including scaling factors, graph- and template-based scaling methods. In graph-based scaling methods, we have explored the application of various technologies in estimation of the average inter-ridge distance. In template-based scaling methods, we have developed an estimation method using Delaunay triangulation algorithm. The experiments show that the performance achieved by using this framework is better than that of original system. With a scaling module, the average EER in our experiments drops from 27.78% to 13.89%. DOI: http://dx.doi.org/10.11591/telkomnika.v11i3.2304

Surface Microstructures on Planar Substrates and Textile Fibers Guide Neurite Outgrowth: A Scaffold Solution to Push Limits of Critical Nerve Defect Regeneration?

The treatment of critical size peripheral nerve defects represents one of the most serious problems in neurosurgery. If the gap size exceeds a certain limit, healing can't be achieved. Connection mismatching may further reduce the clinical success. The present study investigates how far specific surface structures support neurite outgrowth and by that may represent one possibility to push distance limits that can be bridged. For this purpose, growth cone displacement of fluorescent embryonic chicken spinal cord neurons was monitored using time-lapse video. In a first series of experiments, parallel patterns of polyimide ridges of different geometry were created on planar silicon oxide surfaces. These channel-like structures were evaluated with and without amorphous hydrogenated carbon (a-C:H) coating. In a next step, structured and unstructured textile fibers were investigated. All planar surface materials (polyimide, silicon oxide and a-C:H) proved to be biocompatible, i.e. had no adverse effect on nerve cultures and supported neurite outgrowth. Mean growth cone migration velocity measured on 5 minute base was marginally affected by surface structuring. However, surface structure variability, i.e. ridge height, width and inter-ridge spacing, significantly enhanced the resulting net velocity by guiding the growth cone movement. Ridge height and inter-ridge distance affected the frequency of neurites crossing over ridges. Of the evaluated dimensions ridge height, width, and inter-ridge distance of respectively 3, 10, and 10 µm maximally supported net axon growth. Comparable artificial grooves, fabricated onto the surface of PET fibers by using an excimer laser, showed similar positive effects. Our data may help to further optimize surface characteristics of artificial nerve conduits and bioelectronic interfaces.

Hollow Dentures: Treatment Option for Atrophic Ridges. A Clinical Report

Severely atrophic ridges provide decreased retention, support, and stability and pose a clinical challenge to the success of complete denture prostheses. Extreme ridge resorption also increases the interridge distance. Restoration of the vertical dimension and esthetics thus demands increased height of the prosthesis and in turn leads to an increase in prosthesis weight. Reducing the weight of the denture enhances stability and retention and reduces further resorption of the jaw, thereby favoring the prognosis of the denture. This report describes the rehabilitation of an edentulous patient with resorbed maxillary and mandibular ridges and an increased interridge distance using simplified techniques of fabricating hollow dentures.

Pleated turtle escapes the box – shape changes in Dermochelys coriacea

Typical chelonians have a rigid carapace and plastron that form a box-like structure that constrains several aspects of their physiology and ecology. The leatherback sea turtle, Dermochelys coriacea, has a flexible bony carapace strengthened by seven longitudinal ridges, whereas the plastron is reduced to an elliptical outer bony structure, so that the ventrum has no bony support. Measurements of the shell were made on adult female leatherbacks studied on the feeding grounds of waters off Nova Scotia (NS) and on breeding beaches of French Guiana (FG) to examine whether foraging and/or breeding turtles alter carapace size and/or shape. NS turtles exhibited greater mass and girth for a given curved carapace length (CCL) than FG turtles. Girth:CCL ratios rose during the feeding season, indicating increased girth. Measurements were made of the direct (straight) and surface (curved) distances between the medial longitudinal ridge and first right-hand longitudinal ridge (at 50% CCL). In NS turtles, the ratio of straight to curved inter-ridge distances was significantly higher than in FG turtles, indicating distension of the upper surfaces of the NS turtles between the ridges. FG females laid 11 clutches in the breeding season; although CCL and curved carapace width remained stable, girth declined between each nesting episode, indicating loss of mass. Straight to curved inter-ridge distance ratios did not change significantly during the breeding season, indicating loss of dorsal blubber before the onset of breeding. The results demonstrate substantial alterations in size and shape of female D. coriacea over periods of weeks to months in response to alterations in nutritional and reproductive status.

Hollow Maxillary Complete Denture

Residual ridge resorption is the reduction in size of the bony ridge under the mucoperiosteum. The resorption occurs at a faster rate in mandibular arch as compared to the maxillary arch; but severely atrophic maxillae with large interridge distance often pose a clinical challenge during fabrication of a successful maxillary complete denture. This clinical report describes a simple technique of fabricating a hollow maxillary complete denture in a patient with resorbed maxillary and mandibular ridges with increased interridge distance which reduces the weight of the prosthesis and thereby enhances the retention.