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1.
Nature ; 597(7874): 77-81, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34471275

RESUMEN

The amount of carbon stored in deadwood is equivalent to about 8 per cent of the global forest carbon stocks1. The decomposition of deadwood is largely governed by climate2-5 with decomposer groups-such as microorganisms and insects-contributing to variations in the decomposition rates2,6,7. At the global scale, the contribution of insects to the decomposition of deadwood and carbon release remains poorly understood7. Here we present a field experiment of wood decomposition across 55 forest sites and 6 continents. We find that the deadwood decomposition rates increase with temperature, and the strongest temperature effect is found at high precipitation levels. Precipitation affects the decomposition rates negatively at low temperatures and positively at high temperatures. As a net effect-including the direct consumption by insects and indirect effects through interactions with microorganisms-insects accelerate the decomposition in tropical forests (3.9% median mass loss per year). In temperate and boreal forests, we find weak positive and negative effects with a median mass loss of 0.9 per cent and -0.1 per cent per year, respectively. Furthermore, we apply the experimentally derived decomposition function to a global map of deadwood carbon synthesized from empirical and remote-sensing data, obtaining an estimate of 10.9 ± 3.2 petagram of carbon per year released from deadwood globally, with 93 per cent originating from tropical forests. Globally, the net effect of insects may account for 29 per cent of the carbon flux from deadwood, which suggests a functional importance of insects in the decomposition of deadwood and the carbon cycle.


Asunto(s)
Ciclo del Carbono , Bosques , Insectos/metabolismo , Árboles/metabolismo , Animales , Secuestro de Carbono , Clima , Ecosistema , Mapeo Geográfico , Cooperación Internacional
2.
Ecol Appl ; 33(6): e2890, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37212374

RESUMEN

Outbreaks of the spongy moth Lymantria dispar can have devastating impacts on forest resources and ecosystems. Lepidoptera-specific insecticides, such as Bacillus thuringiensis var. kurstaki (BTK) and tebufenozide, are often deployed to prevent heavy defoliation of the forest canopy. While it has been suggested that using BTK poses less risk to non-target Lepidoptera than leaving an outbreak untreated, in situ testing of this assumption has been impeded by methodological challenges. The trade-offs between insecticide use and outbreaks have yet to be addressed for tebufenozide, which is believed to have stronger side effects than BTK. We investigated the short-term trade-offs between tebufenozide treatments and no-action strategies for the non-target herbivore community in forest canopies. Over 3 years, Lepidoptera and Symphyta larvae were sampled by canopy fogging in 48 oak stands in southeast Germany during and after a spongy moth outbreak. Half of the sites were treated with tebufenozide and changes in canopy cover were monitored. We contrasted the impacts of tebufenozide and defoliator outbreaks on the abundance, diversity, and functional structure of chewing herbivore communities. Tebufenozide treatments strongly reduced Lepidoptera up to 6 weeks after spraying. Populations gradually converged back to control levels after 2 years. Shelter-building species dominated caterpillar assemblages in treated plots in the post-spray weeks, while flight-dimorphic species were slow to recover and remained underrepresented in treated stands 2 years post-treatment. Spongy moth outbreaks had minor effects on leaf chewer communities. Summer Lepidoptera decreased only when severe defoliation occurred, whereas Symphyta declined 1 year after defoliation. Polyphagous species with only partial host plant overlap with the spongy moth were absent from heavily defoliated sites, suggesting greater sensitivity of generalists to defoliation-induced plant responses. These results demonstrate that both tebufenozide treatments and spongy moth outbreaks alter canopy herbivore communities. Tebufenozide had a stronger and longer lasting impact, but it was restricted to Lepidoptera, whereas the outbreak affected both Lepidoptera and Symphyta. These results are tied to the fact that only half of the outbreak sites experienced severe defoliation. This highlights the limited accuracy of current defoliation forecast methods, which are used as the basis for the decision to spray insecticides.


Asunto(s)
Bacillus thuringiensis , Insecticidas , Mariposas Nocturnas , Animales , Ecosistema
3.
J Sleep Res ; 31(3): e13508, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-34693583

RESUMEN

Compliance with a mandibular advancement device is important for the optimal treatment of obstructive sleep apnea. Recent advances in information and communication technology-based monitoring and intervention for chronic diseases have enabled continuous monitoring and personalized management. Self-evaluation and self-regulation through objective monitoring and feedback may improve compliance. The aim of this study was to evaluate the effects of information and communication technology-based remote monitoring and feedback services, using a smartphone application, on the objective compliance with a mandibular advancement device in patients with obstructive sleep apnea. Forty individuals who were diagnosed with obstructive sleep apnea by polysomnography were randomly assigned to groups A and B. During an initial 6-week evaluation period, the mandibular advancement device-wearing time was monitored with the smartphone application in group B, but not in group A. The two groups then switched the monitoring procedures during the second 6-week period (the smartphone application was then used by group B, but not by group A). If no input data were indicated on the cloud server of the smartphone application during the monitored period, push notifications were provided twice daily. Objective compliance, monitored by a micro-recorder within the mandibular advancement device, was noted and compared based on whether the monitoring service was provided. The number of mandibular advancement device-wearing days was significantly higher in the monitored period than in the unmonitored period. The mandibular advancement device-wearing time did not differ significantly between the two groups. In conclusion, information and communication technology-based remote monitoring and feedback services demonstrated a potential to increase the objective measures of compliance with mandibular advancement devices.


Asunto(s)
Avance Mandibular , Apnea Obstructiva del Sueño , Retroalimentación , Humanos , Ferulas Oclusales , Apnea Obstructiva del Sueño/terapia , Resultado del Tratamiento
4.
Int J Legal Med ; 135(4): 1369-1374, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33907870

RESUMEN

Due to the advantages of single-nucleotide polymorphisms (SNPs) in forensic science, many forensic SNP panels have been developed. However, the existing SNP panels have a problem that they do not reflect allele frequencies in Koreans or the number of markers is not sufficient to perform paternity testing. Here, we filtered candidate SNPs from the Ansan-Ansung cohort data and selected 200 SNPs with high allele frequencies. To reduce the risk of false inclusion and false exclusion, we calculated likelihood ratios of alleged father-child pairs from simulated families when the alleged father is the true father, the close relative of the true father, and the random man. As a result, we estimated that 160 SNPs were needed to perform paternity testing. Furthermore, we performed validation using Twin-Family cohort data. When 160 selected SNPs were used to calculate the likelihood ratio, paternity and non-paternity were accurately distinguished. Our set of 160 SNPs could be useful for paternity testing in Koreans.


Asunto(s)
Pueblo Asiatico/genética , Frecuencia de los Genes , Paternidad , Polimorfismo de Nucleótido Simple , Adulto , Anciano , Femenino , Humanos , Funciones de Verosimilitud , Masculino , Persona de Mediana Edad , Linaje , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , República de Corea
5.
Virus Genes ; 57(5): 443-447, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34260046

RESUMEN

Foot-and-mouth disease virus (FMDV) A/ASIA/Sea-97 is a predominant lineage in Southeast Asia and East Asia. However, Sea-97 lineage has not been well studied since its first outbreak in Thailand in 1997. Thus, we conducted phylogenetic and evolutionary analysis of Sea-97 using 224 VP1 sequences of FMDV A/ASIA during 1960 and 2018. Phylogenetic analysis revealed that Sea-97 lineage can be classified into five groups (G1-G5). After the emergence of G2 from G1, the genetic diversity of Sea-97 increased sharply, causing divergence into G3, G4 and G5. During this evolutionary process, Sea-97 lineage, which was initially found only in some countries in Southeast Asia, gradually spread to East Asia. The evolution rate of this lineage was estimated to be 1.2 × 10-2 substitutions/site/year and there were many differences in amino acid residues compared to vaccine strain. Substitutions at antigenically important sites may affect the efficacy of the vaccine, suggesting the need for appropriate vaccine strains. Our results could provide meaningful information to understand comprehensive characteristic of Sea-97 lineage.


Asunto(s)
Enfermedades de los Bovinos/genética , Virus de la Fiebre Aftosa/genética , Fiebre Aftosa/genética , Filogenia , Animales , Antígenos Virales/genética , Bovinos , Enfermedades de los Bovinos/patología , Enfermedades de los Bovinos/virología , Brotes de Enfermedades , Fiebre Aftosa/clasificación , Fiebre Aftosa/virología , Virus de la Fiebre Aftosa/clasificación , Virus de la Fiebre Aftosa/patogenicidad , Humanos , Serogrupo , Tailandia , Vacunas Virales/genética
6.
J Prosthet Dent ; 125(3): 479-485, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32276824

RESUMEN

STATEMENT OF PROBLEM: Conventional fabrication of complete denture metal bases is being replaced by the computer-aided design and computer-aided manufacturing (CAD-CAM) systems. However, a comparative analysis of subtractive and additive CAD-CAM manufacturing techniques is lacking. PURPOSE: The purpose of this in vitro study was to compare the adaptation of complete denture metal bases fabricated by milling (subtractive manufacturing) and stereolithography apparatus (SLA) and digital light processing (DLP) (additive manufacturing). MATERIAL AND METHODS: Thirty metal bases were manufactured by using the milling (MIL group), SLA (SLA group), and DLP (DLP group) techniques. The silicone replica technique was used to evaluate the adaptation of the complete denture metal bases, and 30 silicone blocks were fabricated. The silicone block was cut equally in the canine, first molar, and second molar areas. The gap between the model and the metal base was measured by using a digital microscope at the 3 locations, and the measured data were statistically analyzed by using a statistical software program (α=.05). RESULTS: The gaps measured at the 3 areas showed significant differences in all 3 groups (P<.05). At the anterior, middle, and posterior areas, the SLA group showed the narrowest gap (302 ±31 µm, 241 ±39 µm, 201 ±43 µm, respectively). The SLA group also had the narrowest total gap of the metal bases (218 ±33 µm). CONCLUSIONS: The adaptation of the fabricated metal bases varied significantly across the techniques used but fell within a clinically allowable range. The SLA group was the most precise in the fabrication of complete denture metal bases. Further studies are required to analyze the effects of the layer thickness setting, wax elimination, and casting temperature on the adaptation of metal bases manufactured by using SLA.


Asunto(s)
Diseño Asistido por Computadora , Dentadura Completa , Adaptación Marginal Dental , Diseño de Prótesis Dental , Bases para Dentadura , Estereolitografía
7.
J Prosthet Dent ; 125(1): 139-145, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32089361

RESUMEN

STATEMENT OF PROBLEM: Layer thickness in additive manufacturing has stair-step effects that greatly affect the accuracy of the definitive prosthesis. Although the layer thickness can be set, insufficient data comparing and analyzing the accuracy of the fabricated prosthesis after adjusting the layer thickness are available. PURPOSE: The purpose of this in vitro study was to evaluate and compare the accuracy of trial dentures fabricated with different layer thicknesses by using stereolithography (SLA) apparatus. MATERIAL AND METHODS: A maxillary complete edentulous cast was duplicated with silicone material to make a master gypsum cast which was scanned by using a laboratory scanner and saved as a standard tessellation language (STL) file. This was exported into a computer-aided design software program to produce and store the trial denture. Twenty dentures were fabricated according to the set layer thicknesses (50 µm and 100 µm) by using the SLA. The trueness was measured by scanning the intaglio and cameo surfaces to find the best overlap with the reference model to obtain the root mean square value. The precision was evaluated based on the RMS value gained by superimposing the identical scan data from each group and using the combination formula. The Mann-Whitney U-test was used to confirm significant differences among the groups (α=.05). RESULTS: The trueness of the 50-µm-SLA trial denture and the 100-µm-SLA trial denture was significantly different for the intaglio and cameo surfaces (P<.05). However, the intaglio surface did not show a statistically significant difference (P=.987) for precision, but the cameo surface did (P<.05). CONCLUSIONS: It is clinically more appropriate to set the layer thickness to 100 µm rather than 50 µm for the fabrication of accurate trial dentures by using SLA.


Asunto(s)
Diseño Asistido por Computadora , Maxilar , Dentaduras , Estereolitografía
8.
Am J Orthod Dentofacial Orthop ; 157(6): 843-851, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32487314

RESUMEN

INTRODUCTION: The registration of cone-beam computed tomography (CBCT) images and digital dental models is required for the design and manufacturing of dental devices such as implant guides and surgical wafers. This study aims to register intraoral scan (IS) models and cast scan (CS) models onto CBCT images using 3-dimensional (3D) planning software and evaluate the registration accuracy according to scanning methods and 3D planning software. METHODS: The CBCT image of an artificial skull model with reference markers was taken. The CS model and the IS model were obtained from the same skull model, registered onto the CBCT image using 3D planning software packages providing manual registration (MR) function and point-based registration (PR) functions, and set as the experimental groups. After registration, shell to shell deviations and positional differences between the reference model and the experimental models were evaluated. RESULTS: The shell to shell deviations ranged from 0.03 to 0.18 mm. Deviations in both the maxilla and mandible were significantly different according to scanning methods and software packages. In the anteroposterior direction, the IS-MR and CS-MR groups showed significantly different positions. In the superoinferior direction, the MR and PR groups showed significantly different positions. CONCLUSIONS: The registration using the PR function of the 3D planning software packages was significantly more accurate than the registration using the MR function. There was no significant difference between the registrations using the IS model and the CS model when using the PR functions.


Asunto(s)
Imagenología Tridimensional , Modelos Dentales , Tomografía Computarizada de Haz Cónico , Maxilar , Programas Informáticos
9.
J Prosthet Dent ; 116(4): 536-542, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27174406

RESUMEN

STATEMENT OF PROBLEM: The fit of an interim implant restoration (IIR) is important for the effective treatment of patients with partial edentulism. However, no clinical trials have evaluated the marginal and internal fittings achieved with various fabrication methods. PURPOSE: The purpose of this in vitro study was to evaluate and compare the marginal and internal discrepancies in IIRs produced with 3 different methods. MATERIAL AND METHODS: Partially edentulous maxillary and mandibular casts from a transfer abutment were used. Prostheses were prepared by applying wax to the implant abutment. Shapes were copied using putty. IIRs were fabricated from poly(methyl methacrylate) for a conventional system with thermoplastic resin (CTR, n=40), a 4-axial milling machine with a crown-designed standard template library for a subtractive manufacturing system with Pekkton milling (SPM, n=40), and a 3-dimensional printer for an additive manufacturing system with digital light processing (ADL, n=40). The marginal and internal discrepancies were evaluated in each group using the silicone replica technique. The space between the abutment and the intaglio surface of the prosthesis was evaluated with a digital microscope (×160 magnification). Results were analyzed with nonparametric 2-way analysis of variance using rank-transformed values and Tukey post hoc test (α=.05). RESULTS: The fabricated IIRs were significantly different at all points (P<.001). Moreover, ADL was superior to CTR and SPM. IIRs were significantly different only at the intermarginal discrepancy (the vertical discrepancy between the crown and the point where the margin becomes round and changes to the axial wall), the axiogingival discrepancy (the vertical discrepancy between the internal surface and the axial wall adjacent to the gingival wall of the abutment), and the occlusal discrepancy (the vertical discrepancy between the occlusal wall of the abutment and the internal surface; this discrepancy comprises the internal discrepancy; P<.001). No significant differences were found among the IIRs at the marginal discrepancy (the vertical discrepancy between the abutment margin and the crown; P>.111) and the axio-occlusal discrepancy (the vertical discrepancy between the axial wall adjacent to the occlusal wall of the abutment and the internal surface; this discrepancy comprises the internal discrepancy; P>.257). CONCLUSIONS: ADL was superior to the other 2 fabrication methods. However, all 3 methods were suitable because they produced a marginal fit which was within the clinically acceptable range.


Asunto(s)
Adaptación Marginal Dental , Diseño de Prótesis Dental/métodos , Dentadura Parcial Provisoria , Pilares Dentales , Técnica de Colado Dental , Diseño de Implante Dental-Pilar , Humanos , Técnicas In Vitro
10.
J Prosthet Dent ; 115(6): 768-72, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26794702

RESUMEN

STATEMENT OF PROBLEM: Little information is available on the translucency of zirconia-based pressable ceramic restorations with a pressed ceramic veneer and zirconia core in various thickness combinations. PURPOSE: The purpose of this in vitro study was to assess the translucency of 3 types of zirconia-based pressable ceramics for different core-veneer thickness combinations. MATERIAL AND METHODS: A bilayered ceramic specimen was prepared with a pressable ceramic (IPS e.max Zirpress, Initial IQ, Rosetta UltraPress) veneer over a zirconia core (Zenostar Zr). Three groups of specimens (n=7) were formed with the following core+veneer thicknesses: 1 +0.5 mm, 0.7 +0.8 mm, and 0.5 +1 mm. To obtain consistent thickness and high translucency, all specimens were subjected to surface grinding with a grinding machine. To eliminate the effect of differences in roughness on the translucency, the surface roughness of the ground specimens was measured with a scanning profiler, and the consistency of these measured values was verified through statistical analysis. The luminous transmittance of the specimens was measured with a spectrophotometer. The effects of the pressable ceramic type and core-veneer thickness combination on transmittance were assessed using a 2-way ANOVA (α=.05). RESULTS: The consistency of the surface roughness among the tested specimens was confirmed using a 1-way ANOVA and the Tukey HSD post hoc test (P<.05). The luminous transmittance exhibited a statistically significant dependence on both the type of pressable ceramic and the core-veneer thickness combination (P<.05). CONCLUSIONS: The type of pressable ceramic and core-veneer thickness combination affected the translucency of the restoration.


Asunto(s)
Cerámica/uso terapéutico , Coronas con Frente Estético , Técnica de Perno Muñón , Circonio/uso terapéutico , Cerámica/química , Humanos , Luz , Espectrofotometría , Circonio/química
11.
Commun Biol ; 6(1): 338, 2023 04 04.
Artículo en Inglés | MEDLINE | ID: mdl-37016087

RESUMEN

Insects are declining, but the underlying drivers and differences in responses between species are still largely unclear. Despite the importance of forests, insect trends therein have received little attention. Using 10 years of standardized data (120,996 individuals; 1,805 species) from 140 sites in Germany, we show that declines occurred in most sites and species across trophic groups. In particular, declines (quantified as the correlation between year and the respective community response) were more consistent in sites with many non-native trees or a large amount of timber harvested before the onset of sampling. Correlations at the species level depended on species' life-history. Larger species, more abundant species, and species of higher trophic level declined most, while herbivores increased. This suggests potential shifts in food webs possibly affecting ecosystem functioning. A targeted management, including promoting more natural tree species composition and partially reduced harvesting, can contribute to mitigating declines.


Asunto(s)
Ecosistema , Bosques , Humanos , Animales , Árboles/fisiología , Insectos , Cadena Alimentaria
13.
Nat Ecol Evol ; 4(9): 1204-1212, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32661404

RESUMEN

The habitat heterogeneity hypothesis predicts that biodiversity increases with increasing habitat heterogeneity due to greater niche dimensionality. However, recent studies have reported that richness can decrease with high heterogeneity due to stochastic extinctions, creating trade-offs between area and heterogeneity. This suggests that greater complexity in heterogeneity-diversity relationships (HDRs) may exist, with potential for group-specific responses to different facets of heterogeneity that may only be partitioned out by a simultaneous test of HDRs of several species groups and several facets of heterogeneity. Here, we systematically decompose habitat heterogeneity into six major facets on ~500 temperate forest plots across Germany and quantify biodiversity of 12 different species groups, including bats, birds, arthropods, fungi, lichens and plants, representing 2,600 species. Heterogeneity in horizontal and vertical forest structure underpinned most HDRs, followed by plant diversity, deadwood and topographic heterogeneity, but the relative importance varied even within the same trophic level. Among substantial HDRs, 53% increased monotonically, consistent with the classical habitat heterogeneity hypothesis but 21% were hump-shaped, 25% had a monotonically decreasing slope and 1% showed no clear pattern. Overall, we found no evidence of a single generalizable mechanism determining HDR patterns.


Asunto(s)
Biodiversidad , Ecosistema , Animales , Aves , Alemania , Plantas
14.
Genomics Inform ; 18(3): e33, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33017877

RESUMEN

This paper describes a community effort to improve earlier versions of the full-text corpus of Genomics & Informatics by semi-automatically detecting and correcting PDF-to-text conversion errors and optical character recognition errors during the first hackathon of Genomics & Informatics Annotation Hackathon (GIAH) event. Extracting text from multi-column biomedical documents such as Genomics & Informatics is known to be notoriously difficult. The hackathon was piloted as part of a coding competition of the ELTEC College of Engineering at Ewha Womans University in order to enable researchers and students to create or annotate their own versions of the Genomics & Informatics corpus, to gain and create knowledge about corpus linguistics, and simultaneously to acquire tangible and transferable skills. The proposed projects during the hackathon harness an internal database containing different versions of the corpus and annotations.

15.
Nat Commun ; 10(1): 4757, 2019 10 18.
Artículo en Inglés | MEDLINE | ID: mdl-31628336

RESUMEN

Recent progress in remote sensing provides much-needed, large-scale spatio-temporal information on habitat structures important for biodiversity conservation. Here we examine the potential of a newly launched satellite-borne radar system (Sentinel-1) to map the biodiversity of twelve taxa across five temperate forest regions in central Europe. We show that the sensitivity of radar to habitat structure is similar to that of airborne laser scanning (ALS), the current gold standard in the measurement of forest structure. Our models of different facets of biodiversity reveal that radar performs as well as ALS; median R² over twelve taxa by ALS and radar are 0.51 and 0.57 respectively for the first non-metric multidimensional scaling axes representing assemblage composition. We further demonstrate the promising predictive ability of radar-derived data with external validation based on the species composition of birds and saproxylic beetles. Establishing new area-wide biodiversity monitoring by remote sensing will require the coupling of radar data to stratified and standardized collected local species data.


Asunto(s)
Biodiversidad , Bosques , Radar , Tecnología de Sensores Remotos/métodos , Árboles/fisiología , Animales , Aves/clasificación , Aves/fisiología , Escarabajos/clasificación , Escarabajos/fisiología , Conservación de los Recursos Naturales/métodos , Modelos Teóricos , Reproducibilidad de los Resultados , Análisis Espacio-Temporal , Árboles/clasificación
16.
J Adv Prosthodont ; 9(3): 159-169, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28680546

RESUMEN

PURPOSE: The purposes of this study were to evaluate the marginal and internal gaps, and the potential clinical applications of three different methods of dental prostheses fabrication, and to compare the prostheses prepared using the silicone replica technique (SRT) and those prepared using the three-dimensional superimposition analysis (3DSA). MATERIALS AND METHODS: Five Pekkton, lithium disilicate, and zirconia crowns were each manufactured and tested using both the SRT and the two-dimensional section of the 3DSA. The data were analyzed with the nonparametric version of a two-way analysis of variance using rank-transformed values and the Tukey's post-hoc test (α = .05). RESULTS: Significant differences were observed between the fabrication methods in the marginal gap (P < .010), deep chamfer (P < .001), axial wall (P < .001), and occlusal area (P < .001). A significant difference in the occlusal area was found between the two measurement methods (P < .030), whereas no significant differences were found in the marginal gap (P > .350), deep chamfer (P > .719), and axial wall (P > .150). As the 3DSA method is three-dimensional, it allows for the measurement of arbitrary points. CONCLUSION: All of the three fabrication methods are valid for measuring clinical objectives because they produced prostheses within the clinically acceptable range. Furthermore, a three-dimensional superimposition analysis verification method such as the silicone replica technique is also applicable in clinical settings.

17.
J Prosthodont Res ; 61(2): 106-112, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27484816

RESUMEN

PURPOSE: The purpose of this in vitro study was to compare and analyze the three-dimensional marginal and internal fit of PEKK and zirconia copings. METHODS: Two acrylic models of the right maxillary canine, first molar were fabricated as master dies and duplicated by one-step dual viscosity impressions. Five stone replicas from each model were digitized with a blue-light scanner and copings were machined from Pekkton and Zirconia blanks. The inner surface of all the copings and two original acrylic models were digitized by a highly accurate optical scanner. By superimposing the digitized coping data with the CAD-reference die three-dimensionally, visual fit-discrepancies were drawn by calculating the root mean square (RMS) and visualized on a color-difference map. Each calculated RMS-value was statistically analyzed by 3-way ANOVA. In addition, Student's t-test was conducted in order to verify the significance (α=.05) of fit-discrepancies based on the type of abutment tooth and the materials. RESULTS: Mean RMS-values for marginal fit (internal fit) ranged from 51.64±1.5 (36.12±1.34) to 69.62±8.11 (41.6±1.63)µm. Differences in marginal fit (canine: P=.001; molar: P=.047) and internal fit (canine: P=.017; molar: P=.046) were statistically significant. The results of the 3-way ANOVA showed statistically significant differences in the RMS values of the two groups for the material (P<.001), the types of the abutment tooth (P<.001), and the measured region (P<.001). CONCLUSIONS: The marginal and internal fit of both PEKK and zirconia copings of both canine and molar were within the clinically acceptable range. However, the PEKK presented better fitness compared with the zirconia.


Asunto(s)
Diseño Asistido por Computadora , Diseño de Implante Dental-Pilar/métodos , Adaptación Marginal Dental , Materiales Dentales , Diseño de Prótesis Dental/métodos , Imagenología Tridimensional , Cetonas , Circonio , Coronas , Diente Canino , Técnica de Impresión Dental , Humanos , Modelos Dentales , Diente Molar
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