Filling of extraction sockets with autogenous bone in cats

OBJETIVO: Avaliar a regeneração óssea de alvéolos dentais de gatos após enxertia. MÉTODOS: Dezoito gatos adultos, distribuídos em três grupos de 6 animais cada, foram submetidos a extração do canino mandibular direito ou esquerdo. No grupo 1, controle, o alvéolo foi deixado vazio. No grupo 2, o alvéolo foi preenchido com osso esponjoso autógeno do osso ilíaco e no grupo 3, com raspa de osso cortical do osso ilíaco. Os animais foram submetidos à eutanásia 6 semanas após a cirurgia. RESULTADOS: Nas radiografias realizadas no pós-operatório imediato na projeção ventrodorsal observou-se uma área de radiolucência correspondente ao local da alveolectomia e extração dentária. Diminuição da radiolucência foi verificada nas radiografias realizadas seis semanas após a cirurgia. Nos cortes histológicos verificou-se a presença de trabéculas ósseas. A porcentagem de tecido ósseo esponjoso presente nos alvéolos dentais foi quantificada por exames histométricos. Não houve diferença estatisticamente significante entre os grupos (Teste de Kruskal-Wallis p > 0.05) (grupo 1: 52,54 ± 15,4; grupo 2: 50,51 ± 5,01; grupo 3: 51,85 ± 9,52). CONCLUSÃO: Os alvéolos dentais de gatos preenchidos com osso esponjoso autógeno ou raspa de osso cortical autógeno apresentaram regeneração óssea similar àquela observada no grupo controle, após um período de observação de seis semanas.

Root canal adhesive filling in dogs' teeth with or without coronal restoration: A histopathological evaluation

The purpose of this study was to evaluate in vivo the response of the periradicular tissues after endodontic treatment and root filling with Epiphany/Resilon (Penntron Clinical Technologies, LLC, Wallingford, CT) or gutta percha and new Sealapex (SybronEndo, Glendora, CA) in dogs' teeth with or without coronal restoration. Teeth without coronal restorations were used to assess the influence of continuous exposure to the oral environment on the periradicular tissues. Sixty root canals with vital pulps in three dogs were instrumented and obturated in a single session and randomly assigned to one of four groups as follows. group 1: root canal filling with Epiphany/Resilon with coronal restoration, group 2: root canal filling with Sealapex sealer and gutta percha with restoration, group 3: root canal filling with Epiphany/Resilon without restoration, and group 4: root canal filling with Sealapex sealer and gutta percha without coronal restoration. After 90 days, the animals were euthanized, and the maxillas and mandibles were removed and submitted for histologic processing. Longitudinal sections were obtained and stained with hematoxylin and eosin, Mallory's trichrome, and Brown and Brenn stains and examined under light microscopy. There were significant differences found between the four groups (p < 0.05). The results showed that roots canals filled with Epiphany/Resilon, with coronal restoration, had significantly less periradicular inflammation than roots canals filled with gutta percha and Sealapex, with coronal restoration (p = 0.021). No significant difference was observed in the intensity of inflammation between roots canals filled with Epiphany/ Resilon with no restoration and roots filled with gutta percha and Sealapex with restoration (p = 0.269). Roots canals filled with gutta percha and Sealapex sealer without coronal restoration showed the greatest degree of periradicular inflammation.

Reducing the gap between mobile and intelligent software agents

This paper presents an approach to integrate an artificial intelligence (AI) technique, concretely rule-based processing, into mobile agents. In particular, it focuses on the aspects of designing and implementing an appropriate inference engine of small size to reduce migration costs. The main goal is combine two lines of agent research, First, the engineering oriented approach on mobile agent architectures, and, second, the AI related approach on inference engines driven by rules expressed in a restricted subset of first-order predicate logic (FOPL). In addition to size reduction, the main functions of this type of engine were isolated, generalized and implemented as dynamic components, making possible not only their migration with the agent, but also their dynamic migration and loading on demand. A set of classes for representing and exchanging knowledge between rule-based systems was also proposed.

Phase separation and gap bowing in zinc-blende InGaN, InAlN, BGaN, and BAlN alloy layers

We present first-principles calculations of the thermodynamic and electronic properties of the zinc-blende ternary InxGa1-xN. InxAl1-xN, BxGa1-xN, and BxAl1-xN alloys. They are based on a generalized quasi-chemical approximation and a pseudopotential-plane-wave method. T-x phase diagrams for the alloys are obtained, We show that due to the large difference in interatomic distances between the binary compounds a significant phase miscibility gap for the alloys is found. In particular for the InxGa1-xN alloy, we show also experimental results obtained from X-ray and resonant Raman scattering measurements, which indicate the presence of an In-rich phase with x approximate to 0.8. For the boron-containing alloy layers we found a very high value for the critical temperature for miscibility. similar to9000 K. providing an explanation for the difficulties encountered to grow these materials with higher boron content. The influence of a biaxial strain on phase diagrams, energy gaps and gap bowing of these alloys is also discussed. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Relationship between the optical gap and the optical-absorption tail breadth in amorphous GaAs

We study the relationship between the optical gap and the optical-absorption tail breadth for the case of amorphous gallium arsenide (a-GaAs). In particular, we analyze the optical-absorption spectra corresponding to some recently prepared a-GaAs samples. The optical gap and the optical-absorption tail breadth corresponding to each sample is determined. Plotting the optical gap as a function of the corresponding optical-absorption tail breadth, we note that a trend, similar to that found for the cases of the hydrogenated amorphous silicon and hydrogenated amorphous germanium, is also found for the case of a-GaAs. The impact of alloying on the optical-absorption spectrum associated with a-GaAs is also briefly examined. (C) 2004 American Institute of Physics.

Evaluation of periapical repair following retrograde filling with different root-end filling materials in dog teeth with periapical lesions

Objective. The objective of this study was to evaluate periapical repair following retrograde filling using different root-end filling materials.Study design. After induction of periapical lesions, 48 root canals from do teeth were partially filled. Endodontic surgery was performed and 3 different materials were used for root-end filling: Sealer 26, Sealapex plus zinc oxide, or mineral trioxide aggregate (NITA). No additional procedures were performed in the control group after partial filling of the root canal. After 180 days, the animals were killed, the rnaxillas and mandibles were removed, and specimens were submitted for histologic processing.Results. Histopathologic analysis revealed similar periapical repair for the groups in which Sealer 26, Sealapex plus zinc oxide, and MTA were used (P >.05). The control group showed unsatisfactory periapical repair W <.05).Conclusion. There was no difference in periapical tissue healing alter retrograde filling with the tested materials, which indicates that these 3 root-end filling materials are equally useful.

Gap solitons in superfluid boson-fermion mixtures

Using coupled equations for the bosonic and fermionic order parameters, we construct families of gap solitons (GSs) in a nearly one-dimensional Bose-Fermi mixture trapped in a periodic optical-lattice (OL) potential, the boson and fermion components being in the states of the Bose-Einstein condensation and Bardeen-Cooper-Schrieffer superfluid, respectively. Fundamental GSs are compact states trapped, essentially, in a single cell of the lattice. Full families of such solutions are constructed in the first two band gaps of the OL-induced spectrum, by means of variational and numerical methods, which are found to be in good agreement. The families include both intragap and intergap solitons, with the chemical potentials of the boson and fermion components falling in the same or different band gaps, respectively. Nonfundamental states, extended over several lattice cells, are constructed too. The GSs are stable against strong perturbations.

Histological evaluation of MTA as a root-end filling material

Aim To assess the histological response associated with grey mineral trioxide aggregate (GMTA) and zinc oxide eugenol (ZOE) as root-end filling materials in teeth where the root canals were not filled and the coronal access cavities were not restored.Methodology Periapical lesions were developed in 24 premolar teeth in three dogs. The root canals were prepared and half of them were dried, filled and the coronal access restored (closed). The remaining teeth were not root filled and no coronal restoration was placed (open). Apical root-end resections were performed 3 mm from the apex, and root-end cavities were prepared with ultrasonic tips. These were randomly filled with either ZOE or GMTA in the same number of specimens using MAPSYSTEM device. After 180 days the animals were killed and blocks of tissues removed and processed for histological examination. Periradicular tissue reaction was evaluated, including severity of inflammation and cementum formation. Statistical analysis was performed using ANOVA analysis and Tukey's test.Results A significant difference was found between the levels of inflammation in the periradicular tissues of the GMTA/closed group, compared with the ZOE/open and ZOE/closed groups (P < 0.05) but not between GMTA/closed and GMTA/open groups. Cementum formation was not found over any ZOE specimens but over MTA in all specimens. No microorganisms were found in the interface between the material and the dentinal walls.Conclusions GMTA was associated with less periapical inflammation and tissue response when used as a root-end filling material, even when no root filling or coronal restoration was present.

Effect of root canal filling material and level of surgical injury on periodontal healing in dogs

Some divergencies in the literature about periodontal healing after surgical injury stimulated the development of this experiment. The root canals of dogs' teeth were negotiated and filled by the lateral condensation technique with two kinds of sealers: Sealapex and zinc oxide-eugenol cement. In the second session, the bone tissue was exposed and one cavity was made at the apical third of the root and another at the border between the coronal and middle thirds, both penetrating into the root canal. Six months later the animals were sacrificed and the specimens prepared for histopathologic analysis. The results showed that the kind of filling material and the level of the periodontal wound exposing the root canal can influence the healing process (P<0.01).

Mineral trioxide aggregate as a root canal filling material in reimplanted teeth. Microscopic analysis in monkeys

This study analyzed mineral trioxide aggregate (MTA) as a root canal filling material for the immediate reimplantation of monkey teeth. Four adult capuchin monkeys Cebus apella were used, which had their maxillary and mandibular lateral incisors on both sides extracted and reimplanted after 15 min. During the extra-alveolar period, the teeth were kept in saline solution and after reimplantation retention was performed with a stainless steel wire and composite resin for 14 days. After 7 days, the reimplanted teeth were submitted to endodontic treatment with biomechanics up to file n. 30 and irrigation with a saturated solution of calcium hydroxide [Ca(OH)(2)], and then divided into two study groups: group I - root canal filled with a Ca(OH)(2) paste, and group II - root canal filled with MTA. Radiographic follow up was performed at 30, 60 and 90 days postoperatively, and after 180 days the animals were killed and specimens were processed for histomorphological analysis. The results revealed that most specimens of both groups presented organized periodontal ligament with no inflammation. The resorptions observed were surface resorptions and were repaired by cementum. Both MTA and Ca(OH)(2) were good root canal filling materials for immediately reimplanted teeth, providing good repair and also allowing biological sealing of some lateral canals. There was no significant difference between the study groups (alpha = 29.60%).