Effectiveness Of Restoration Techniques Research Articles

Effects of Restoration Techniques on Plant Diversity and Forage Biomass in Areas Invaded by Prosopis juliflora

Effects of Restoration Techniques on Plant Diversity and Forage Biomass in Areas Invaded by Prosopis juliflora

Effect of restoration technique on resistance to fracture of endodontically treated anterior teeth with flared root canals.

This study was designed to compare the impact of post and core systems on resistance to fracture of endodontically treated anterior teeth with flared root canals and to assess their fracture pattern. Sixty central incisors were cut horizontally 2 mm coronal to the cementoenamel junction (CEJ). After root canal therapy, teeth were assigned into 6 groups (n=10 each) based on a post system and used as follows: Group C, non-flared root received size #1 glass fiber posts (Control); Group AP, flared root restored with anatomical post; Group RC, flared root restored with size #1 fiber post and cemented with thick layer of resin cement; Group CR, flared root restored with size #1 and reinforced with composite resin; Group CM, cast post-core; Group CP, CAD/CAM polymer-infiltrated ceramic post and core. Following post cementation, core build-up and crown insertion, the specimens were thermo-cycled up to 10,000 cycles (5C/55C; 30 seconds dwell time, 6 seconds transition time) and then statically loaded at 1 mm/minute crosshead speed using a universal testing machine. One-way ANOVA and Tukey HSD post hoc test (α=0.05) were used for data analysis. Group C recorded significantly higher resistance to fracture values [(826.9±39.1) N] followed by group CP [(793.8±55.6) N] while group RC yielded the lowest fracture resistance values [(586.7±51.4) N]. The resistance to fracture of wide root canals can be enhanced by using one-piece CAM/CAM post and core as an alternative to the use of either glass fiber post, relined with composite resin increasing the thickness of luting cement or the use of cast post and core system. However, this was an in vitro investigation and further in vivo studies are necessary.

Effect of restoration technique on stress distribution in extensively destroyed premolars: a finite element analysis study

ABSTRACT Objective: The objective of this study by the finite element method was to analyze the stress distribution on a single-rooted mandibular premolar tooth restored in two different ways. Methods: Laboratory simulation considered the following situations: 1) premolar restored with gold cast post and ceramic crown; 2) premolar restored with glass fiber post, composite resin core and ceramic crown. For this we used a two-dimensional model of a premolar with load application of 300N in the axial and oblique directions within the ANSYS program for Windows. Results: Under the axial load, a higher concentration of stresses was observed around the cast post (166 MPa). In the oblique load simulation, there was a concentration of stresses on the buccal root wall, internally and externally, in the tooth restored with cast post (222 MPa). In both load directions, the glass fiber post dissipated the stress received with greater uniformity (55 to 111 MPa). Conclusion: These data suggested that from the biomechanical point of view, the use of a glass fiber post and composite resin core could be more advantageous than the cast post technique for a mandibular single-rooted premolar tooth.

Effect of restoration technique on stress distribution in roots with flared canals: an FEA study.

The aim of this finite element analysis (FEA) study was to test the effect of different restorative techniques on stress distribution in roots with flared canals. Five three-dimensional (3D) FEA models that simulated a maxillary incisor with excessive structure loss and flared root canals were created and restored with the following techniques/materials: 1) a prefabricated post: 2) one main and two accessory posts; 3) i-TFC post-core (Sun Medical); 4) the thickness of the root was increased by using composite resin and the root was then restored using a prefabricated post; 5) an anatomic post was created by using composite resin and a prefabricated glass-fiber post. Composite cores and ceramic crowns were created. A 300-N static load was applied at the center of the palatal surface of the tooth to calculate stress distributions. SolidWorks/Cosmosworks structural analysis programs were used for FEA analysis. The analysis of the von Mises and tensile stress values revealed that prefabricated post, accessory post, and i-TFC post systems showed similar stress distributions. They all showed high stress areas at the buccal side of the root (3.67 MPa) and in the cervical region of the root (> 3.67 MPa) as well as low stress accumulation within the post space (0 to 1 MPa). The anatomic post kept the stress within its body and directed less stress towards the remaining tooth structure. The creation of an anatomic post may save the remaining tooth structure in roots with flared canals by reducing the stress levels.

Effects of Restoration Techniques on Soil Carbon and Nitrogen Dynamics in Florida Longleaf Pine (Pinus palustris) Sandhill Forests

Historic fire suppression and intensive forest management in longleaf pine (Pinus palustris) sandhill forests has resulted in hardwood encroachment and degradation of this fire-dependent ecosystem. Active management is now required to restore native community structure and composition, but little is known about the long-term impacts of typical restoration techniques on ecosystem properties. In 1994, the Longleaf Pine Restoration Project (LPRP) was established in fire-excluded longleaf pine sandhills of Eglin Air Force Base, Florida, to explore the effects of restoration treatments on plant and animal community composition and soil processes. Experimental treatments applied included three hardwood reduction techniques and delayed burn. Reference sites were concurrently monitored. Fifteen years later, we revisited the LPRP plots to determine whether soil processes showed lasting treatment effects. This study showed that there were no differences in soil C and N between the reference and the fire-suppressed plots prior to the treatments, suggesting that soil C and N were relatively resistant to degradation. This study also showed that the restoration treatments had a significant effect by reducing soil C, but this effect was only short-lived (<3 years). In addition, a MRPP (multi-response permutation procedure) analysis showed that only the herbicide treatment was still different from the reference plots 15 years after the initial treatments. Thus, this study suggests that repeated fires (or lack of) or hardwood removal treatments have little detectable effect on soil nutrients in these nutrient-poor ecosystems.

Are only the strong surviving? Little influence of restoration on beetles (Coleoptera) in an agricultural landscape

Habitat restoration has become an important part of biodiversity conservation in the face of extensive habitat loss and fragmentation, especially in agricultural landscapes. Study of invertebrates such as beetles (Coleoptera) may be important to assess the effectiveness of restoration techniques in maintaining native fauna, because they provide a variety of trophic roles and ecosystem services. In this study we examined the conservation value for beetles of revegetation in linear strips and alongside remnant patches compared with remnant vegetation and cleared roadsides. We also assessed how habitat variables structured beetle community composition. Beetle species richness and abundance did not substantially differ between revegetated, remnant and cleared areas, and was not substantially influenced by vegetation type and structure. Herbivorous beetles and the family Curculionidae were more species rich in cleared linear strips. Beetle fauna in these agricultural landscapes may be a robust subset of the pre-clearing beetle community, possibly due to the widespread degradation of remnant areas and the ground layer habitats within them. One beetle species had slightly higher abundance in remnant linear strips, suggesting that remnant habitats may be important for some beetle species. Importantly, environmental variables strongly influenced beetle community composition, signifying that beetle communities are still responding to factors such as soil type and native vegetation, rather than variables mainly associated with land management. The restoration practices currently being undertaken in agricultural areas may not maintain beetle species that require specific habitat variables to survive. Ground-layer attributes need to be included in future revegetation projects, and translocation of specialist species of beetles may be required to restore communities.

LONG-TERM MONITORING AND ASSESSMENT OF A STREAM RESTORATION PROJECT IN CENTRAL NEW YORK

Monitoring, assessment and reporting of stream restoration projects have historically lagged far behind implementation. However, in recent years, rigorous post-project assessments (PPAs) of modern stream restoration practices have steadily increased. This has helped to stimulate debate and inquiry regarding the effectiveness of restoration techniques and has provided critical feedback to practitioners and planners useful in restoration design and implementation. Nonetheless, few studies exist that track the performance of modern restoration projects over a protracted period. Instead, most are based on a brief snapshot taken during the initial post-construction period, which may not always accurately characterize longer-term project performance. Here, we re-visit a stream restoration project implemented in 2005 on a third-order stream in central New York. By repeating several of our quantitative and qualitative evaluation procedures from the original 2007 PPA we demonstrate that (i) despite several recent large flood events and the fact that the current channel geometry differs from the design/as-built configuration, the project has made substantial progress towards the goals of channel stabilization and habitat enhancement; (ii) this more favourable, mid-term outcome was not necessarily evident during or well-predicted by our 2007 PPA; (iii) although continued deformation of in-stream structures may be a harbinger of future channel instability, riparian vegetation is playing an increasingly important role in maintaining channel stability; and (iv) accurately predicting local scour depths proximal to in-stream structures, performing a detailed sediment budget analysis, and prescribing adequate bank protection are critical to project success, especially during early stages of a project. Copyright © 2013 John Wiley & Sons, Ltd.

Effect of restorative techniques on fracture resistance of endodontically treated premolars

Purpose: This study was aimed to evaluate the effect of restorative materials and glass fiber post on the fracture resistance of endodontically treated premolars. Material and Methods: Fifty extracted single rooted lower premolars were used in this in vitro study and divided into 5 groups: sound teeth (control group); mesial-occlusal-distal (MOD) preparation + endodontic treatment + composite restoration; MOD preparation + endodontic treatment + glass fiber post + composite restoration; MOD preparation + endodontic treatment + amalgam restoration; MOD preparation + endodontic treatment + glass fiber post + amalgam restoration. The specimens were loaded on a universal testing machine at the crosshead speed of1 mm/min until fracture. The data were analyzed using two-way ANOVA test. Results: The mean loads at fracture were 860.11 N, 801.79 N, 761.39 N, 737.14 N and 707.85 N respectively. There were no statistically significant differences (P > 0.05) in the fracture resistance of teeth restored with composite and amalgam, as well as restored with or without glass fiber post. Conclusions: The type of restorative material and the usage of glass fiber post do not have visible influence on the fracture resistance of the endodontically treated mandibular premolars.

The effects of restoration techniques on protozoan communities in mandarin fish culture ponds, based on an artificial substrate

By use of the polyurethane foam unit (PF unit) method, structural and functional data for protozoan communities were assessed as indicators of the effect of restoration techniques in mandarin fish culture ponds. A total of 165 species of protozoa were observed, including 76 species of ciliates, 57 species of phytomastigophorans, 14 species of zoomastigophorans, and 18 species of sarcodinas. In June, 97 protozoan species colonized the PF units. In August, the number of colonizing species was only 78. In November, a total of 139 species were recorded. In June and August the co-dominant species of protozoans were mainly heterotrophic creatures which feed on bacteria and organic detritus. In November, the co-dominant species were mostly phytoflagelates. The average DO value in the control pond was very low at all times throughout the survey. Removing the sediment, changing the water, and adding compound microbiological preparation had substantial and important effects on reducing total ammonium nitrogen and nitrite nitrogen. Compared with the control ponds, the numbers of protozoan species colonizing the experimental ponds reached its maximum level more slowly and the protozoan community pollution values were lower. The dynamic characteristics of the protozoan colonization process and community pollution values were in agreement with water eutrophic status and could be used for efficient monitoring of the effects of restoration techniques.

The effect of restoration techniques on non‐target species: case studies in moorland ecosystems

AbstractQuestions: What is the impact on non‐target species of restoration methods to establish Calluna vulgaris on grass‐dominated moorlands?Location: A Nardus stricta‐dominated moorland in Wales and a Molinia caerulea‐dominated moorland in Northern England, UK.Methods: Two replicated experiments were established on grass‐dominated moorlands. The treatments comprised disturbance (rotavation and trampling by animals), addition of Calluna seed, and three different grazing regimes, together with a no grazing control.Results: The creation of bare ground and addition of seed increased the establishment of the desired dominant shrub, Calluna vulgaris. In the Nardus sward, rotavation and trampling were equally successful in establishing Calluna, but rotavation was more successful in the Molinia sward. Rotavation inhibited the growth of competitive grass species better than trampling. However, the disturbance techniques were detrimental to other components of the plant community, causing a decline in the cover of desirable species such as Vaccinium myrtillus and other dwarf shrub species and a small increase in the occurrence of undesirable species such as Juncus effusus. Grazing also controlled competitive grass species: Festuca ovina decreased in cover at a grazing intensity of 1.5 ewes/ha; Molinia caerulea and Agrostis spp. declined when cattle were included in the grazing regime, but increased in cover when ungrazed or when grazed at 1.5 ewes/ha.Conclusions: When restoration concentrates on the establishment of one or a few species, it is important to monitor how the techniques used affect the rest of the plant community – particularly with regard to losses of desirable species or increases in undesirable species.

Effect of filler content of flowable composites on resin-cavity interface

The purpose of this in vitro study was to evaluate marginal integrity and wall adaptation in 1- and 2-mm-deep cavities restored with a high filler-loaded flowable composite in comparison to a flowable composite with lower filler content and a conventional hybrid composite. 1-mm-deep dentin and 2-mm-deep enamel-dentin Class I cavities were prepared and restored with a self-etch adhesive and with one of the composites. Samples were crosscut and evaluated for marginal integrity and gap formation using a digital microscope. Selected samples were also observed using a scanning electron microscope. For 1-mm-deep cavities, no differences in marginal integrity and wall adaptation were observed among the three composites. For 2-mm-deep cavities, those restored with the bulk technique and with the higher filler-loaded flowable composite demonstrated a similar outcome as that of the conventional hybrid composite. On the effect of restorative techniques, cohesive enamel defects were observed in bulk-filled 2-mm-deep cavities. However, when the incremental technique was used in conjunction with the higher filler-loaded flowable composite and the conventional hybrid composite for 2-mm-deep cavities, superior results were obtained.

Effects of restoration techniques on breeding birds in a thermally-impacted bottomland hardwood forest

We evaluated the effects of revegetation techniques on breeding bird communities in a bottomland hardwood forest impacted by thermal effluent. In 1993, sections of the Pen Branch bottomland on the Savannah River Site, South Carolina, were herbicide-treated (glyphosate), burned, and planted; other sections were planted only while others were unaltered and served as controls. Few differences in the avian community occurred at 1 and 2 years post-treatment among treatments. Plots that were herbicide-treated, burned, and planted had greater species richness in 1994 and abundance in 1995 than sections that were planted only ( P<0.05). Bird species composition differed slightly among treatments and White-eyed Vireos ( Vireo griseus), Common Yellowthroats ( Geothlypis trichas), Indigo Buntings ( Passerina cyanea), and Red-winged Blackbirds ( Agelaius phoeniceus) were the most abundant species in the corridor. Revegetation techniques used to restore this thermally-impacted bottomland had little effect on the avian communities 1 and 2 years post-treatment.

Marginal leakage with different composite restorative materials: effect of restorative techniques

The degrees of marginal leakage was tested for different restorative techniques with use of both ultraviolet-polymerized and cold-curing resins. All the materials tested showed severe marginal leakage when applied as conventional butt joint restorations. When the restorations were extended onto peripheral etched enamel, either with or without a sealant-primed etched surface, marginal leakage was prevented in most instances with both the cold-curing and ultraviolet-polymerized materials. However, the ultraviolet-polymerized sealant was more effective in preventing marginal leakage than the cold-curing sealants when applied as a covering over the restorations and extended onto the peripheral etched enamel.