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Better Adaptation (good + adaptation)
Selected AbstractsModified Class II open sandwich restorations: evaluation of interfacial adaptation and influence of different restorative techniquesEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2002Ingrid E. Andersson-Wenckert The sandwich technique with resin-modified glass ionomer cement (RMGIC) has been proposed to relieve the contraction stresses of direct resin composite (RC) restorations. The aim of this study was to evaluate the interfacial adaptation to enamel and dentin of modified Class II open RMGIC/RC sandwich restorations and the influence of different light curing techniques and matrix bands. Forty box-shaped Class II fillings were placed in vivo in premolars scheduled for extraction after one month. In groups I and II, a metal matrix was used; RC was inserted with horizontal (group I) and diagonal (group II) increments and cured with indirect/direct light. Group III was performed as group II, but a transparent matrix was used. Group IV was as group II, but with a separating liner between RMGIC and RC. Group V was a closed sandwich restoration. Interfacial quality was studied using SEM replica technique. Gap-free interfacial adaptation to enamel was observed for RMGIC in 70%, for RC in 70% and to dentin for RMGIC in 81%, for RC in 56%. No significant differences were seen between the experimental groups. At the cervical margins, RMGIC showed significantly better adaptation to enamel than RC, 74% and 42%, respectively. In conclusion, the investigated restorations showed a high percentage of gap-free interfacial adaptation in vivo. Interfacial adaptation to dentin and to cervical enamel was significantly better for RMGIC than for RC. [source] Ex vivo microscopic assessment of factors affecting the quality of apical seal created by root-end fillingsINTERNATIONAL ENDODONTIC JOURNAL, Issue 8 2007S. I. Tobón-Arroyave Abstract Aim, (i) To evaluate the incidence of microcracks around root-end preparations completed with ultrasonic tips and their relationship with the root filling technique and thickness of surrounding dentine. (ii) To investigate the effect of rapid exposure to a water-soluble dye of Intermediate Restorative Material (IRM), Super Ethoxybenzoic Acid (sEBA) and Mineral Trioxide Aggregate (MTA), on the marginal adaptation and microleakage of root-end fillings. (iii) To describe the microstructure of the surface of root-end filling materials. Methodology, Ninety-two single-rooted teeth were divided into two groups (n = 46) according to the root canal instrumentation/filling techniques. Group 1 consisted of specimens in which canal preparation was completed using a crown-down technique and then filled with the Thermafil system (TF group); Group 2 consisted of specimens in which canal preparation was completed using a step-back technique and lateral condensation (LC group). Following root-end resection and ultrasonic cavity preparation, the samples were further divided into three subgroups (n = 24) for root-end filling with IRM, sEBA or MTA. The ultrasonic preparation time was recorded. Eight teeth were kept as positive and 12 as negative controls. Following immersion in Indian ink for 7 days, all resected root surfaces were evaluated for the presence of microcracks and the cross-sectional area of root-end surface and root-end filling were measured to evaluate the thickness of the dentinal walls. Thereafter, the samples were sectioned longitudinally so as to assess the depth of dye penetration and marginal adaptation of root-end fillings. Negative controls longitudinally sectioned were used to describe microstructural characteristics of the root-end filling materials using scanning electron microscopic (SEM) techniques. Results, Although the thickness of dentinal walls between groups 1 and 2 was similar, the ultrasonic preparation time and number of microcracks were significantly higher (P < 0.001) in the TF group. Both groups had a significant correlation between microcracks and ultrasonic preparation time (P < 0.001). sEBA and IRM had better adaptation and less leakage compared with MTA. A SEM analysis displayed microstructural differences between the root-end filling materials. Conclusion, Microcracks can occur independently of the thickness of dentinal walls and may be associated with the prolonged ultrasonic preparation time required for the removal of the root filling during root-end cavity preparation. Although sEBA and IRM had better behaviour than MTA regarding microleakage and marginal adaptation, it is possible that exposure of MTA to a water-soluble dye before achieving full set and its porous microstructure contributed to the results. [source] Asymmetric allele-specific expression in relation to developmental variation and drought stress in barley hybridsTHE PLANT JOURNAL, Issue 1 2009Maria Von Korff Summary In the present study, we analysed allele-specific expression (ASE) in the selfing species barley to assess the frequency of cis -acting regulatory variation and the effects of genetic background, developmental differences and drought stress on allelic expression levels. We measured ASE ratios in 30 genes putatively involved in stress responses in five hybrids and their reciprocals, namely Hordeum spontaneum 41-1/Alexis (HAl), Hordeum spontaneum 41-1/Arta (HAr), Sloop/WI3408 (SW), Tadmor/Sloop (TS) and Tadmor/WI3408 (TW). In order to detect cis -acting variation related to drought and developmental changes, the barley hybrids were grown under control and water-limited conditions, and leaf tissue was harvested at two developmental stages. The analysis demonstrated that more than half of the genes measured (63%) showed allelic differences in expression of up to 19-fold due to cis -regulatory variation in at least one cross by treatment/stage combination. Drought stress induced changes in allelic expression ratios, indicating differences between drought responsive cis -elements. In addition, ASE differences between developmental stages suggested the presence of cis -acting elements interacting with developmental cues. We were also able to demonstrate that the levels and frequency of allelic imbalance and hence differences in cis -regulatory elements are correlated with the genetic divergence between the parental lines, but may also arise as an adaptation to diverse habitats. Our findings suggest that cis -regulatory variation is a common phenomenon in barley, and may provide a molecular basis of transgression. Differential expression of near-isogenic members of the same gene family could potentially result in hybrid lines out performing their parents in terms of expression level, timing and response to developmental and environmental cues. Identification and targeted manipulation of cis -regulatory elements will assist in breeding improved crops with a better adaptation to changing environments. [source] Gonadal maturation in the blackspot seabream Pagellus bogaraveo: a comparison between a farmed and a wild broodstockJOURNAL OF FISH BIOLOGY, Issue 2004V. Micale The blackspot seabream Pagellus bogaraveo(Brünnich, 1768) has been regarded as a possible alternative to traditionally cultured Mediterranean species such as seabream and seabass, due to its high market value and good adaptation to captivity. Broodstock establishment and management represent the first step towards reliable production of eggs and fry, which is required to develop aquaculture of this new species. Two different broodstocks were tested for gonadal maturation and spawning, one constituting of wild fish caught as juveniles and reared in tanks until sexual maturity (4 years), and one assembled from wild adult fish caught during or just before the reproductive season. All fish were maintained under the same rearing conditions and fed the same diet. Gonadal stripping and biopsies were performed weekly to monitor maturation in both males and females. Ovarian samples were staged for maturity on the basis of follicular diameter and migration of germinal vesicle. Sperm samples were tested for density (number of spermatozoa ml,1) and motility. The fish reared in captivity reached ovarian maturity during the breeding season of the wild stock. Eggs were obtained by stripping from both farmed and wild specimens, but appeared degenerated as a result of being retained too long in the ovarian cavity due to the absence of spontaneous spawning. Spermiation was prolonged in the farmed fish, but appeared to be blocked in the wild breeders after first sampling. However, the sperm was very viscous and the motile spermatozoa did not exceed 10%. [source] | ||||||||||