Life cycle of Ixodes luciae (Acari: Ixodidae) in the laboratory

The life cycle of Ixodes luciae was evaluated for five consecutive generations in the laboratory. Wild mice Calomys callosus and laboratory rats Rattus norvegicus were used as hosts for larvae and nymphs. For adult ticks, opossums Didelphis aurita were used as hosts. Off-host developmental periods were observed in an incubator at 27A degrees C and 95% RH. The life cycle of I. luciae lasted 95-97 days, excluding prefeeding periods. C. callosus, one of the natural host species for I. luciae immature stages, was shown to be much more suitable than the artificial host R. norvegicus. Significantly (P < 0.05), more larvae and nymphs successfully fed on C. callosus than on R. norvegicus. When tick-na < ve C. callosus were exposed to three consecutive larval infestations at 24-day intervals, recovery of engorged larvae were greater in the second and third infestations, indicating that previous infestations did not induce acquired resistance to ticks. Larval feeding period typically varied from 5 to 10 days on R. norvegicus, but was significantly (P < 0.05), longer on C. callosus (range, 7-34 days). The majority (71.7%) of I. luciae adult females successfully fed and oviposited after exposed to D. aurita. Mean engorged weight (581.9 mg; range, 237.1-796.0 mg) of these females were much higher than those previously reported for other New World Ixodes species. Our results are in accordance to the current literature that appoints opossums Didelphidae and small rodents (e.g., C. callosus) natural hosts for I. luciae immature and adult stages, respectively.

Biology and life cycle of Amblyomma incisum (Acari: Ixodidae)

Amblyomma incisum Neumann is a major tick species in the Atlantic Forest of Brazil. Tapir is the main host for adult ticks and a high aggressiveness of nymphs to humans has been reported. In this work data on the biology and life cycle of this tick species is presented for the first time. It was shown that horse is a suitable host for A. incisum adults and rabbit for larvae and nymphs. It was also shown that A. incisum is a big tick species (mean engorged female weight of 1.96 g) with a long life cycle which lasts 262.3 days when maintained at 27A degrees C and 85% RH. These laboratory conditions were, however, inappropriate and egg hatching rate (1.2%) was very low. Nevertheless egg hatching of ticks in a forest patch increased considerably (72.2%) indicating that this A. incisum population is highly dependent on a forest-like environment.

The immunomodulatory effects of Ipomoea cornea in rats vary depending on life stage

Ipomoea cameo Jacq. ssp. fistulosa (Mart. Ex Choisy; Convolvulaceae; I. cameo) possesses a toxic component: an indolizidine alkaloid swainsonine (SW) that has immunomodulatory effects due to its inhibition of glycoprotein metabolism. It is also known that SW is excreted into both the amniotic fluid and milk of female rats exposed to I. cameo. Thus, the aim of this study was to determine whether SW exposure, either in utero or from the milk of dams treated with I. cornea, modulates offspring immune function into adulthood. In addition, adult (70 days old) and juvenile rats (21 days old) were exposed to I. cameo in order to evaluate several other immune parameters: lymphoid organs relative weight and cellularity, humoral and cellular immune responses. Offspring exposed to I. cornea during lactation developed rheumatoid arthritis (RA) in adulthood after an immunogenic challenge. In addition, both adult and juvenile rats exposed to I. cameo showed discrepancies in several immune parameters, but did not exhibit any decrease in humoral immune response, which was enhanced at both ages. These findings indicate that SW modulates immune function in adult rats exposed to SW during lactation and in juvenile and adult rats exposed to SW as juveniles and adults, respectively.

Argon ion laser and halogen lamp activation of a dark and light resin composite: microhardness after long-term storage

The objective of this study was to evaluate in vitro light activation of the nano-filled resin composite Vita shade A1 and A3 with a halogen lamp (QTH) and argon ion laser by Knoop microhardness profile. Materials and methods: Specimens of nanofilled composite resin (Z350-3 M-ESPE) Vita shade A1 and A3 were prepared with a single increment inserted in 2.0-mm-thick and 3-mm diameter disc-shaped Teflon mold. The light activation was performed with QTH for 20 s (with an intensity of approximately 1,000 mW/cm(2) and 700 mW/cm(2)) and argon ion laser for 10 s (with a power of 150 mW and 200 mW). Knoop microhardness test was performed after 24 h and 6 months. The specimens were divided into the 16 experimental groups (n = 10), according to the factors under study: photoactivation form, resin shade, and storage time. Knoop microhardness data was analyzed by a factorial ANOVA and TukeyA ` s tests at the 0.05 level of significance. Results: Argon ion laser was not able to photo-activate the darker shade of the nanofilled resin composite evaluated but when used with 200 mW it can be as effective as QTH to photo-activate the lighter shade with only 50% of the time exposure. After 6 months storage, an increase in the means of Knoop microhardness values were observed. Conclusions: Light-activation significantly influenced the Knoop microhardness values for the darker nanofilled resin composite.

Tooth Replantation After Use of Euro-Coffins Solution or Bovine Milk as Storage Medium: A Histomorphometric Analysis in Dogs

Purpose: Euro-Collins solution was developed for the preservation of organs for transplantation, whose characteristics have raised interest for its use as a storage medium for avulsed teeth before replantation. This study evaluated histologically and morphometrically the healing process of dog teeth replanted after storage in Euro-Collins solution or bovine milk. Materials and Methods: Eighty roots of 4 young adult mongrel clogs were randomly assigned to 4 groups (n = 20) and the root canals were instrumented and obturated with gutta-percha and a calcium hydroxide-based sealer. After 2 weeks, the teeth were extracted and subjected to the following protocols: GI (negative control), replantation immediately after extraction; GII (positive control), bench-drying for 2 hours before replantation; GIII and GIV, immersion in 10 mL of whole bovine milk and Euro-Collins solution at 4 C, respectively, for 8 hours before replantation. The animals were sacrificed 90 days postoperatively. The pieces containing the replanted teeth were subjected to routine processing for histologic and histometric analyses under light microscopy and polarized light microscopy. Results: Root resorption was observed in all groups. GII exhibited the greatest loss of dental structure (P < .01), and inflammatory resorption was predominant in this group. Storage in milk showed poorer results than immediate replantation and storage in Euro-Collins solution (P < .01). The teeth stored in Euro-Collins solution presented similar extension of root resorption and periodontal ligament reorganization to those of immediately replanted teeth. Conclusions: The findings of this study suggest that the Euro-Collins solution is an adequate storage medium for keeping avulsed teeth for up to 8 hours before replantation. Crown Copyright (C) 2010 Published by Elsevier Inc on behalf of American Association of Oral and Maxillofacial Surgeons. All rights reserved. Oral Maxillofac Surg 68:111-119, 2010

Propolis as storage media for avulsed teeth: microscopic and morphometric analysis in rats

The maintenance of the avulsed teeth in appropriate media for preserving the cellular viability has been important for repairing the periodontal ligament and preventing the root resorption after tooth reimplantation. Propolis is a substance capable of preserving cellular viability. This study aimed to analyze the propolis substance as a storage media for maintaining the avulsed teeth, besides to determine the ideal time period for keeping the tooth inside it. Thus, 60 maxillary right central incisors of rats were extracted and divided into five groups. In groups I and II, teeth were kept in propolis for 60 min and 6 h, respectively; in group III, teeth were kept in milk for 6 h; in group IV, teeth were kept dry for 60 min; and in group V, they were immediately reimplanted. All teeth had their root canals filled with calcium hydroxide paste. Following, teeth were reimplanted in their sockets. After 15 and 60 days, animals were killed and the obtained samples were processed in laboratory for microscopic and morphometric analyzing. The results showed that the occurrence of inflammatory resorption, dental ankylosis and the formation of the connective tissue parallel to the root surface were similar among groups. It could be verified a greater occurrence of replacement resorption in group IV when comparing to other groups. In groups I and IV, the presence of periodontal ligament-like connective tissue was substantially smaller than the other groups. Regarding to the cementum amount over the root, it could be observed that this was present in smaller amount in groups I and IV. Group II was similar to groups III and IV. Therefore, according to the results of this study, the use of propolis as a storage media for maintaining avulsed teeth could be highlighted, and the 6-h period was more appropriate than the 60-min period.

A longitudinal study of quality of life of elderly with mandibular implant-supported fixed prostheses

Objectives: To verify the consequences of implant-supported fixed oral rehabilitation on the quality of life (QL) of elderly individuals. Material and methods: Fifteen patients were studied, being 10 females and five males; all were aged > 60 years, were completely edentulous, wore removable dentures on both arches, and were treated with implant-supported fixed dentures. Three QL questionnaires were applied, two related to the oral conditions (Oral Impact on Daily Performance - OIDP - and Oral Health Impact Profile, short version - OHIP-14) and one dealing with global aspects (World Health Organization Quality of Life - WHOQOL-BREF), before 3, 6, and 18 months after surgical placement of implants. Results: Scores in the OIDP and OHIP-14 questionnaires were better after dental treatment. The WHOQOL-BREF was less sensitive, confirming the higher reliability of specific questionnaires (focal) compared with general questions in such situations. Conclusion: Treatment with implant-supported fixed prostheses improved QL in the elderly; these effects are better detected by specific instruments focused on the subject.

Microhardness of resin cements in the intraradicular environment: Effects of water storage and softening treament

Objectives. To analyze the microhardness of four dual-cure resin cements used for cementing fiber-reinforced posts under the following conditions: after 7 days of storage in water, after additional 24 h of immersion in 75% ethanol, and after 3 months of storage in water. Hardness measurements were taken at the cervical, middle and apical thirds along the cement line. Methods. Root canals of 40 bovine incisors were prepared for post space. Fibrekor (R) glass fiber-reinforced posts (Jeneric/Pentron) of 1 mm in diameter were cemented using Panavia F 2.0 (Kuraray), Variolink (Ivoclar-Vivadent), Rely X Unicem (3M ESPE) or Duolink (Bisco) (N = 10). After 7 days of water storage at 37 degrees C, half the sample (N = 5) was longitudinally sectioned and the initial microhardness measured along the cement line from cervical to apex. These same samples were further immersed in 75% ethanol for 24 h and reassessed. The remaining half (N = 5) was kept unsectioned in deionized water at 37 degrees C for 3 months, followed by sectioning and measuring. Data were analyzed by a series of two-way ANOVA and Tukey tests at alpha = 5%. Results. Statistically significant differences were identified among the cements, thirds and conditions. Significant interactions were also observed between cements and thirds and between cements and conditions. Panavia F exhibited significantly higher initial microhardness than the other three cements, which showed no statistical difference among themselves. Variolink and Duolink showed significantly higher microhardness values in the cervical third, without significant difference among the thirds for the other cements. Immersion in ethanol significantly reduced the hardness values for all cements, regardless of the thirds. Storage in water for 3 months had no influence on the hardness of most of the cements, with the exception of Unicem that showed a significant increase in the hardness values after this period. Results showed heterogeneity in the microhardness of the cements inside the canal. All cements presented some degree of softening after ethanol treatment, which suggests instability of the polymer. The quality of curing of resin cements in the root canal environment seems unpredictable and highly material dependent. (C) 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Mechanical stability of adhesives under water storage

Objectives. To evaluate the effects of storage condition (wet or dry) and storage time (24 h and 3 months) on the ultimate tensile strength (UTS) of Single Bond (SB), 3M-ESPE; Opti Bond Solo Plus (OB), Kerr; One Step (OS), Bisco, and Prime & Bond NT (PB), Dentsply adhesive resins. Methods. Hourglass-shaped specimens were obtained from a metallic matrix. Each adhesive was dispensed to fill the molds completely and left undisturbed in a dark chamber for 4 min at 37 degrees C for solvent evaporation. They were individually light-cured for 80 s at 500 mW/cm(2) and randomly divided into three groups: 24 h of water storage; 3 months of water storage; 3 months of dry storage. The specimens were tested in tension at 0.5 mm/min using the microtensile method and data were analyzed by two-way ANOVA and SNK tests for each material. Results. Water storage for 3 months did not cause significant changes in the UTS of any of the adhesives (p-value). Values for water storage ranged from 25.9 MPa for Single Bond at 24 h to 32.7 MPa for Prime & Bond NT after 3 months. Dry storage for 3 months yielded significantly higher UTS for most adhesives, which ranged from approximately 20% for Opti Bond to 160% higher values for Single Bond compared to their 3 months wet storage values. Conclusion. The effects of storage condition and time on the UTS of adhesives were material-dependent. (C) 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Fatigue life and failure modes of crowns systems with a modified framework design

Objectives: To evaluate the effect of framework design on the fatigue life and failure modes of metal ceramic (MC, Ni-Cr alloy core, VMK 95 porcelain veneer), glass-infiltrated alumina (ICA, In-Ceram Alumina/VM7), and veneered yttria-stabilized tetragonal zirconia polycrystals (Y-TZP, IPSe.max ZirCAD/IPS e.max,) crowns. Methods: Sixty composite resin tooth replicas of a prepared maxillary first molar were produced to receive crowns systems of a standard (MCs, ICAs, and Y-TZPs, n = 10 each) or a modified framework design (MCm, ICAm, and Y-TZPm, n = 10 each). Fatigue loading was delivered with a spherical steel indenter (3.18 mm radius) on the center of the occlusal surface using r-ratio fatigue (30-300 N) until completion of 10(6) cycles or failure. Fatigue was interrupted every 125,000 cycles for damage evaluation. Weibull distribution fits and contour plots were used for examining differences between groups. Failure mode was evaluated by light polarized and SEM microscopy. Results: Weibull analysis showed the highest fatigue life for MC crowns regardless of framework design. No significant difference (confidence bound overlaps) was observed between ICA and Y-TZP with or without framework design modification. Y-TZPm crowns presented fatigue life in the range of MC crowns. No porcelain veneer fracture was observed in the MC groups, whereas ICAs presented bulk fracture and ICAm failed mainly through the veneer. Y-TZP crowns failed through chipping within the veneer, without core fractures. Conclusions: Framework design modification did not improve the fatigue life of the crown systems investigated. Y-TZPm crowns showed comparable fatigue life to MC groups. Failure mode varied according to crown system. (C) 2010 Elsevier Ltd. All rights reserved.

Study of the effectiveness of propolis extract as a storage medium for avulsed teeth

The purpose of the present study was to evaluate the efficacy of propolis extract in maintaining the viability of human periodontal ligament (PDL) cells, and to radiographically analyze tooth replantation and the adjacent periodontium in dogs after storage in this extract. Human PDL cells were incubated with the experimental media propolis, milk, saliva, Hank`s balanced salt solution (HBSS), and Dulbecco`s modified Eagles medium (DMEM, positive controls), and distilled water (negative control). Cell viability was determined 0, 1, 3, 6, 12, and 24 h later by colorimetric MTT assay. Thirty incisors from dogs were divided into two storage time blocks (1 and 3 h) and were maintained in the experimental media. HBSS served as a positive control, and dry teeth (on gauze) as a negative control. The replanted teeth were radiographed once per month for 6 months. The radiographic images were standardized by the shortening/lengthening factor, and were both qualitatively and quantitatively analyzed. The in vitro results showed that the efficacy of propolis in maintaining functional viability of PDL cells was similar to that of milk. Propolis and milk were significantly better than controls from the 6-h time period. The in vivo results showed that teeth maintained in propolis medium exhibited replacement resorption with significant reduction in tooth length, similar to teeth maintained in saliva and dried teeth. This resorption was less intense with the 3-h storage time than the 1-h storage time. Conditions close to normal were found in teeth maintained in milk, similar to the HBSS control. Therefore, although propolis was effective in maintaining the viability of human PDL cells, resorption of the tooth replantation in dogs occurred under these experimental conditions.

The influence of storage condition and duration on the resistance to fracture of different fiber post systems

Purpose: To evaluate the effects of storage condition and duration on the resistance to fracture of different fiber post systems (and to morphologically assess the post structure before and after storage. Methods: Three types of fiber posts (DT Light Post, GC Post, FRC Postect Plus) were divided in different groups (n=12) according to the storage condition (dry at 37 degrees C; saline water at 37 degrees C; mineral oil at 37 degrees C and storage inside the roots of extracted human teeth immersed in saline water at 37 degrees C and duration (6, 12 months). A universal testing machine loading at a 90 degrees angle was employed for the three-point bending test. The test was carried out until fracture of the post. A 3-way ANOVA and Tukey`s test (alpha= 0.05) were used to compare the effect of the experimental factors on the fracture strength. Two posts of each group were observed before and after the storage using a scanning electron microscope. Results: Storage condition and post type had a significant effect on post fracture strength (P< 0.05). The interaction between these factors was significant (P< 0.05). Water storage significantly decreased the fracture strength, regardless of the post type and the storage duration. Storage inside roots, in oil, and at dry conditions did not significantly affect post fracture strength. SEM micrographs revealed voids between fibers and resin matrix for posts stored in water. Posts stored under the other conditions showed a compact matrix without porosities. (Am J Dent 2009;22:366-370).

Influence of Artificial Accelerated Aging on Dimensional Stability of Acrylic Resins Submitted to Different Storage Protocols

Purpose: The aim of this study was to evaluate the influence of artificial accelerated aging on dimensional stability of two types of acrylic resins (thermally and chemically activated) submitted to different protocols of storage. Materials and Methods: One hundred specimens were made using a Teflon matrix (1.5cmx0.5mm) with four imprint marks, following the lost-wax casting method. The specimens were divided into ten groups, according to the type of acrylic resin, aging procedure, and storage protocol (30 days). GI: acrylic resins thermally activated, aging, storage in artificial saliva for 16 hours, distilled water for 8 hours; GII: thermal, aging, artificial saliva for 16 hours, dry for 8 hours; GIII: thermal, no aging, artificial saliva for 16 hours, distilled water for 8 hours, GIV: thermal, no aging, artificial saliva for 16 hours, dry for 8 hours; GV: acrylic resins chemically activated, aging, artificial saliva for 16 hours, distilled water for 8 hours; GVI: chemical, aging, artificial saliva for 16 hours, dry for 8 hours; GVII: chemical, no aging, artificial saliva for 16 hours, distilled water for 8 hours; GVIII: chemical, no aging, artificial saliva for 16 hours, dry for 8 hours GIX: thermal, dry for 24 hours; and GX: chemical, dry for 24 hours. All specimens were photographed before and after treatment, and the images were evaluated by software (UTHSCSA-Image Tool) that made distance measurements between the marks in the specimens (mm), calculating the dimensional stability. Data were submitted to statistical analysis (two-way ANOVA, Tukey test, p = 0.05). Results: Statistical analysis showed that the specimens submitted to storage in water presented the largest distance between both axes (major and minor), statistically different (p < 0.05) from control groups. Conclusions: All acrylic resins presented dimensional changes, and the artificial accelerated aging and storage period influenced these alterations.