Progressive recovery of osseoperception as a function of the combination of implant-supported prostheses

The extraction of teeth involves the elimination of extremely sensitive periodontal mechanoreceptors, which play an important role in oral sensory perception. Objectives: The aim of this study was to evaluate the recovery of interocclusal sensory perception for micro-thickness in individuals with different types of implant-supported prostheses. Materials and Methods: Wearers of complete dentures (CDs) comprised the negative control group (group A, n=17). The experimental group consisted of wearers of prostheses supported by osseointegrated implants (Group B, n=29), which was subsequently divided into 4 subgroups: B(1) (n=5) - implant supported overdentures (ISO) occluding with CD; B(2) (n=6) - implant-supported fixed prostheses (ISFP) occluding with CD; B3 (n=8) - wearers of maxillary and mandibular ISFP, and B(4) (n=10) - ISFP occluding with natural dentition (ND). Individuals with ND represented the positive control group (Group C, n=24). Aluminum foils measuring 10 mu m, 24 mu m, 30 mu m, 50 mu m, 80 mu m, and 104 mu m thickness were placed within the premolar area, adding up to 120 tests for each individual. Results: The mean tactile thresholds of groups A, B(1), B(2), B(3), B(4), and C were 92 mu m, 27 mu m, 27 mu m, 14 mu m, 10 mu m, and 10 mu m, respectively. [Correction added after publication online 18 April 2008: in the preceding sentence 92 mu m, 27 mu m, 14 mu m, 10 mu m and 10 mu m, was corrected to 92 mu m, 27 mu m, 27 mu m, 14 mu m, 10 mu m and 10 mu m.] The Kruskal-Wallis test revealed significant difference among groups (P < 0.05). The Dunn test revealed that group A was statistically different from groups C, B(3), and B(4), and that B(1) and B(2) were statistically different from group C. Conclusion: Progressive recovery of osseoperception as a function of the combination of implant-supported prostheses could be observed. Moreover, ISO and/or ISFP combinations may similarly maximize the recovery of osseoperception.

Temperature variation at the external root surface during 980-nm diode laser irradiation in the root canal

Objective: To assess the temperature variation in the cervical, middle and apical thirds of root external wall, caused by 980-nm diode laser irradiation with different parameters. Methods: The roots of 90 canines, had their canals instrumented and were randomly distributed into 3 groups (n = 30) according to the laser potency (1.5 W, 3.0 W and 5.0 W). Each group was subdivided into 3 (n = 10) according to the frequency (CM, 100 Hz and 1000 Hz), and each subgroup divided into 2 (n = S): dried canal or filled with distilled water. The maximum temperature values were collected by 3 thermocouples located at each third of the root external wall and recorded by digital thermometers. Results: The groups irradiated in the continuous mode (CM) presented the highest values (11.82 +/- 5.78), regardless of the canals were dry or not, which were statistically different (p < 0.01) from those obtained with 100 Hz (6.22 +/- 3.64) and 1000 Hz (6.00 +/- 3.36), which presented no statistical difference between them (p > 0.01). The groups irradiated with 5.0 W presented the greatest temperature variation (12.15 +/- 5.14), followed by 3.0 W (7.88 +/- 3.92) and 1.5 W (4.02 +/- 2.16), differing between them (p < 0.01). The cervical third of the root presented the highest temperature rises (9.68 +/- 5.80), followed by the middle (7.66 +/- 4.87) and apical (6.70 +/- 4.23), with statistical difference among them (p < 0.01). After 30 s from the end of irradiation, all the specimens presented temperature variation lower than 10 degrees C. Conclusions: Application of 980-nm diode laser in the root, at 1.5 W in all operating modes, and 3.0 W, in the pulsed mode, for 20 s, can safely be used in endodontic treatment, irrespective of the presence of humidity. (C) 2008 Elsevier Ltd. All rights reserved.

In Vitro Evaluation of Bacterial Leakage Along the Implant-Abutment Interface of an External-Hex Implant After Saliva Incubation

The aim of this in vitro study was to evaluate bacterial leakage along the implant-abutment interface under unloaded conditions. Twelve premachined abutments with plastic sleeves and 12 dental implants were used in this study. Prior to tests of bacterial leakage, samples from the inner parts of the implants were collected with sterile microbrushes to serve as negative controls for contamination. After casting, the abutments were tightened to 32 Ncm on the implants. The assemblies were immersed in 2.0 mL of human saliva and incubated for 7 days. After this period, possible contamination of the internal parts of the implants was evaluated using the DNA Checkerboard method. Microorganisms were found in the internal surfaces of all the implants evaluated. Aggregatibacter actinomycetemcomitans and Capnocytophaga gingivalis were the most incident species. No microorganisms were found in the samples recovered from the implants before contamination testing (negative control). Bacterial species from human saliva may penetrate the implant-abutment interface under unloaded conditions. INT J ORAL MAXILLOFAC IMPLANTS 2011;26:782-787

A critical comparison of the external and internal boron requirements for contrasting species in boron-buffered solution culture

Despite reports that boron (B) requirements differ among plant species there is a shortage of critical evidence to demonstrate unequivocally whether species differ in internal or external B requirements or both. The present research was conducted to establish the external and internal B requirements of three contrasting species, a woody dicot (marri), an herbaceous dicot (sunflower) and a monocot (wheat) using B-buffered solution culture. Boron-buffered solution culture provided satisfactory control of external B concentrations ranging from 0.04 to 30 muM throughout the 20- (sunflower and wheat) or 40-day (marri) growth period. At low external B concentrations (less than or equal to 0.13 muM), the growth of marri and sunflower was severely depressed but by contrast the vegetative growth of wheat plants was satisfactory and free of B deficiency symptoms. Marri and sunflower plants achieved total maximum shoot growth at greater than or equal to1.2 muM B in solutions while wheat plants did so at greater than or equal to 0.6 muM B. The critical B concentrations (mg kg(-1) dry matter) in the youngest open leaf blades of marri, sunflower and wheat plants were 17.9, 19.7 and 1.2 on 20, 10 and 10 days after transplanting (DAT), respectively. Lower internal and external B requirements of wheat were matched by a lower uptake rate of B compared to marri and sunflower.

Submandibular gland aplasia and progressive dental caries: A case report

When severe caries occurs in mandibular permanent incisor teeth, the clinician should consider the possibility of associated submandibular gland aplasia or salivary hypofunction. Early diagnosis of submandibular gland disease is essential, as operative problems involving restoration of mandibular incisor teeth are considerable. Furthermore, progressive severe dental caries can present a dilemma for the clinician in affected individuals, despite intensive preventive and restorative therapy. A case report describing severe progressive dental caries and enamel demineralization of the permanent mandibular incisor teeth in a young girl is presented. Further investigation revealed absence of functional bilateral submandibular salivary glands contributing to the rapid breakdown of the teeth despite intensive preventive measures.

Progressive Age-Related Changes Similar to Age-Related Macular Degeneration in a Transgenic Mouse Model

Age-related macular degeneration (AMD) is the major cause of blindness in the developed world. its pathomechanism is unknown and its late onset, complex genetics and strong environmental components have all hampered investigations. Here we demonstrate the development of an animal model for AMD that reproduces features associated with geographic atrophy, a transgenic mouse line (mcd/mcd) expressing a mutated form of cathepsin D that is enzymatically inactive thus impairing processing of phagocytosed photoreceptor outer segments in the retinal pigment epithelial (RPE) cells. Pigmentary changes indicating RPE cell atrophy and a decreased response to flash electroretinograms were observed in 11- to 12-month-old mcd/mcd mice. Histological studies showed RPE cell proliferation, photoreceptor degeneration, shortening of photoreceptor outer segments, and accumulation of immunoreactive photoreceptor breakdown products in the RPE cells. An accelerated photoreceptor cell death was detected in 12-month-old mcd/mcd mice. Transmission electron microscopy demonstrated presence of basal laminar and linear deposits that are considered to be the hallmarks of AMD. Small hard drusen associated with human age-related maculopathy were absent in the mcd/mcd mouse model at the ages analyzed. in summary, this model presents several features of AMD, thus providing a valuable tool for investigating the underlying biological processes and pathomechanism of AMD.

Skin toxins and external parasitism of coral-dwelling gobies

Toxic (Gobiodon spp.) and non-toxic (Paragobiodon xanthosomus) gobies became infected with external parasites (gnathiid isopods) at equal rates in a laboratory experiment. Parasites were evenly distributed over the body of P. xanthosomus but were mostly confined to the fins of Gobiodon spp., where toxin glands are less abundant. Skin toxins were not associated with the rate of infection but their distribution did appear to influence the site of parasite attachment. (C) 2003 The Fisheries Society of the British Isles.

Integrated control of nitrate recirculation and external carbon addition in a predenitrification system

The integrated control of nitrate recirculation and external carbon addition in a predenitrification biological wastewater treatment system is studied. The proposed control structure consists of four feedback control loops, which manipulate the nitrate recirculation and the carbon dosage flows in a highly coordinated manner such that the consumption of external carbon is minimised while the nitrate discharge limits (based on both grab and composite samples) are met. The control system requires the measurement of the nitrate concentrations at the end of both the anoxic and the aerobic zones. Distinct from ordinary control systems, which typically minimise the variation in the controlled variables, the proposed control system essentially maximises the diurnal variation of the effluent nitrate concentration and through this maximises the use of influent COD for denitrification, thus minimising the requirement for external carbon source. Simulation studies using a commonly accepted simulation benchmark show that the controlled system consistently achieves the designated effluent quality with minimum costs.

Brazilian external sector so far in the 21st century

Although Brazil has traditionally been characterized by a culture of inward-looking policy making, the presence of foreign firms in the Brazilian productive sector has always been significant. The share of foreign-owned firms is one of the highest that can be found among developing countries. This article discusses the main features of the external sector of the Brazilian economy, regarding trade flows, foreign investment, the internationalization of Brazilian entrepreneurial groups and the short-term financial requirements in foreign currencies

Variations of the soft tissue thicknesses external to the ribs in Pectus Excavatum patients

Background: Surgical repair of pectus excavatum (PE) has become more popular due to improvements in the minimally invasive Nuss procedure. The pre-surgical assessment of PE patients requires Computerized Tomography (CT), as the malformation characteristics vary from patient to patient. Objective: This work aims to characterize soft tissue thickness (STT) external to the ribs among PE patients. It also presents a comparative analysis between the anterior chest wall surface before and after surgical correction. Methods: Through surrounding tissue segmentation in CT data, STT values were calculated at different lines along the thoracic wall, with a reference point in the intersection of coronal and median planes. The comparative analysis between the two 3D anterior chest surfaces sets a surgical correction influence area (SCIA) and a volume of interest (VOI) based on image processing algorithms, 3D surface algorithms, and registration methods. Results: There are always variations between left and right side STTs (2.54±2.05 mm and 2.95±2.97 mm for female and male patients, respectively). STTs are dependent on age, sex, and body mass index of each patient. On female patients, breast tissue induces additional errors in bar manual

Variations of the soft tissue thicknesses external to the ribs in pectus excavatum patients

Background: Surgical repair of pectus excavatum (PE) has become more popular due to improvements in the minimally invasive Nuss procedure. The pre-surgical assessment of PE patients requires Computerized Tomography (CT), as the malformation characteristics vary from patient to patient. Objective: This work aims to characterize soft tissue thickness (STT) external to the ribs among PE patients. It also presents a comparative analysis between the anterior chest wall surface before and after surgical correction. Methods: Through surrounding tissue segmentation in CT data, STT values were calculated at different lines along the thoracic wall, with a reference point in the intersection of coronal and median planes. The comparative analysis between the two 3D anterior chest surfaces sets a surgical correction influence area (SCIA) and a volume of interest (VOI) based on image processing algorithms, 3D surface algorithms, and registration methods. Results: There are always variations between left and right side STTs (2.54±2.05 mm and 2.95±2.97 mm for female and male patients, respectively). STTs are dependent on age, sex, and body mass index of each patient. On female patients, breast tissue induces additional errors in bar manual

Angular and linear accelerations of a rolling cylinder acted by an external force

The dynamics of a cylinder rolling on a horizontal plane acted on by an external force applied at an arbitrary angle is studied with emphasis on the directions of the acceleration of the centre-of-mass and the angular acceleration of the body. If rolling occurs without slipping, there is a relationship between the directions of these accelerations. If the linear acceleration points to the right, then the angular acceleration is clockwise. On the other hand, if it points to the left, then the angular acceleration is counterclockwise. In contrast, if rolling and slipping occurs, the direction of the linear acceleration does not determine the direction of the angular acceleration. For example, the linear acceleration may point to the right and the angular acceleration clockwise or counterclockwise depending on the external force orientation and point of application.

Trajectórias de profissionalidade e ciclo de vida profissional: um contributo para o conhecimento dos professores de educação especial

Dissertação apresentada à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Ciências da Educação - Especialidade Educação Especial