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Intracoronal sealing ability of two dental cements.

The purpose of this study was to compare the efficacy of sealing the coronal 2-mm of the root canals versus covering the entire pulpal floor with one of two dental-resin cements (Principle or C&B Metabond). Sixty-two molars with the occlusal half of the crowns and the apical half of the roots removed were used. Each canal was enlarged by using a #3 Gates Glidden bur and obturated with unsealed gutta-percha cones. The teeth were randomly assigned to four groups, each containing 15 teeth, plus a negative and a positive control. In group 1, 2 mm of Principle were placed over the entire pulpal floor. In group 2, Principle was placed 2 mm into each canal orifice. Groups 3 and 4 were the same as groups 1 and 2, except C&B Metabond cement was used. After the cement set, the gutta-percha was removed and the integrity of the seal was tested by fluid filtration at a pressure of 20 cm H2O at 1 h and at 1, 2, and 4 weeks. The data were analyzed by a three-way ANOVA and the Student-Newman-Keuls tests at alpha = 0.05. The controls behaved as expected. Results showed that there were no statistically significant differences among the materials used or the location (p > 0.05), but there was a significant difference with respect to time. Principle leaked significantly more than C&B Metabond at 1 h (p < 0.05), but the seal became tighter over time. C&B Metabond leaked less early (p < 0.05) but increased in leakage at 4 weeks. Both materials sealed well over the 4-week study. Principle was easier to use, and sealing the entire pulpal floor was easier than sealing only the canal orifice.

Analysis of Variance↗

Sealing ability of mineral trioxide aggregate and super-EBA when used as furcation repair materials: a longitudinal study.

Immediate sealing of furcation perforations enhances the repair process. The purpose of this study was to longitudinally compare the ability of mineral trioxide aggregate (MTA) and Super-EBA to seal furcation perforations. Fifty-one extracted human maxillary molars were decoronated 3 mm above the CEJ, and the roots were amputated 3 mm below the furcation. A #2 high-speed round bur was used to perforate the center of the furcations. The canals were obturated with gutta-percha, and the root ends were sealed with C&B Metabond. Three experimental groups of 15 teeth each were restored with MTA, Super-EBA, or a combination of MTA in the perforation and a Super-EBA dome on the pulpal floor. Six teeth served as controls. Each tooth was affixed to a fluid filtration device and subjected to a pressure of 20 cm H2O. The integrity of the perforation seal was evaluated initially at 30 min for the Super-EBA and the combination groups and at 4 h for the MTA group. Additional measurements were then made at 24 h, 1 week, and 1 month. The controls behaved as expected. A two-way ANOVA revealed a significant difference (p = 0.01) between materials. Tukey's test isolated the difference to Super EBA as producing a superior seal but only at 24 h. There was no significant effect with time (p = 0.57) or the interaction of the materials with time (p = 0.66). All materials sealed the perforations very well. The maximum leakage of all materials was <0.007 microL min(-1) cm H2O(-1).

Aluminum Compounds↗

High olfactory sensitivity for dimethyl sulphide in harbour seals.

Productive areas are patchily distributed at sea and represent important feeding grounds for many marine organisms. Although pinnipeds are known to travel on direct routes and return regularly to particular feeding sites, the environmental information seals use to perform this navigation is as yet unknown. As atmospheric dimethyl sulphide (DMS) has been demonstrated to be a reliable indicator for profitable foraging areas, we tested seals for their ability to smell DMS at concentrations typical for the marine environment. Using a go/no-go response paradigm we determined the DMS detection threshold in two harbour seals (Phoca vitulina vitulina). DMS stimuli from 8.05 x 108 to 8 pmol (DMS)m(-3)(air) were tested against a control stimulus using a custom-made olfactometer. DMS-thresholds determined for both seals (20 and 13 pmol m(-3)) indicate that seals can detect ambient concentrations associated with high primary productivity, e.g. in the North Atlantic. Thus, seals possess an extraordinarily high olfactory sensitivity for DMS, which could provide a sensory basis for identifying or orienting to profitable foraging grounds.

Animal Migration↗

Effects of calcium hydroxide on physical and sealing properties of canal sealers.

AIM: To investigate whether Ca(OH)2 in four different agents alters the physical properties (Exp. I) and sealing ability (Exp. II) of root canal sealers. EXPERIMENT: (Exp. I) Calcipex (Nippon Sika-Yakuhin, Shimonoseki, Japan), Vitapex (Neo-Dental, Tokyo, Japan), Calkyl (Showa Yakuhin, Tokyo, Japan), and Ca(OH)2 were used as Ca(OH)2 agents. Four sealers were tested for flow, working time, setting time, and film thickness: Canals (Showa Yakuhin), Canals-N (Showa Yakuhin), Ketac -Endo (Espe, Seefeld, Germany), and Sealapex (Kerr, Romulus, MI, USA). Each Ca(OH)2 agent was added to 10 vol.% of each sealer, and the mixture and controls without a Ca(OH)2 agent were tested according to ISO specifications. Measurements were compared using Student's t-tests (P < 0.05). (Exp. II) After removing Ca(OH)2 agents applied to the root canals of 100 extracted human teeth, canals were filled with sealer. Controls were filled with each sealer without Ca(OH)2 agents. Sealing ability was evaluated using distance of dye penetration from the apices. Dye penetration data were compared using analysis of variance and post hoc Newman-Keuls test (P < 0.05). RESULTS: Ca(OH)2 agents influenced the physical properties of the sealers. Flow and setting time met ISO requirements, but film thickness and working time did not. Apical sealing ability of all four sealers was influenced by Ca(OH)2 agents. The sealing ability of Sealapex improved with all Ca(OH)2 agents. The physical and sealing abilities varied among the other sealers. CONCLUSIONS: Contact with Ca(OH)2 agents left on the canal wall caused considerable changes to the sealing ability of sealers.

Calcium Hydroxide↗

Evaluation of a pit- and fissure-sealing program in a public dental health service after 2 years.

The aim of the present study was to test the caries-preventive effect of a bis-GMA type fissure sealant (Concise Enamel Bond System) in a public dental health service for children. The study compared one group of children, in which all sound permanent teeth were sealed, and a control group in which no sealants were placed. During the study period all children received systematic restorative care, while sealing was performed on the basis of diagnoses made at subsequent examinations by one of the authors. After 2 years a total of 187 children were available for re-examination. Sealant retention was comparable to that obtained in previous studies, but no statistically significant reduction in overall caries increment could be demonstrated. Further analysis showed that only 223 sites had been sealed, while the majority of all erupting sites (394) were either carious or filled before they were screened for the purpose of sealing. It is therefore assumed that only teeth less susceptible to occlusal decay were sealed, thereby explaining the lack of benefit derived from the sealing program.

Child, Preschool↗

Microleakage in fissures sealed with resin or glass ionomer cement.

The purpose of this study was to investigate if microleakage occurs in fissures after being sealed with a glass ionomer cement (Fuji III). Ten pairs of contralateral maxillary premolars, to be extracted for orthodontic reasons, were sealed in vivo. Glass ionomer cement was randomly used on one tooth and diluted composite on the contralateral. An air-polishing instrument was used for cleaning the fissures before sealing them. After 14 days the sealant status was recorded clinically and the teeth were extracted. They were placed in a 0.5% solution of methyl blue, subjected to a thermal cycling procedure, and finally sectioned. The sections were photographed in a stereomicroscope, and two observers recorded the microleakage according to a scoring system. Three glass ionomer sealings were clinically recorded as missing, one partly missing, and six intact, while all the resin sealings were present. Extensive leakage was seen in all glass ionomer specimens with dye penetration throughout the material as well as at the interface between cement and enamel. No leakage was seen in the composite specimens. Remnants of glass ionomer cement were observed in most of the sections from teeth which clinically seemed to have lost the sealing. This study indicates that Fuji III is poorly retained in the fissures, and that the material permits leakage even when it is fully retained. The material may, however, prevent caries by release of fluorides, and the fact that remnants of cement were found in fissures which clinically seemed to have lost it, indicates that this may even occur in cases with loss of retention.

Coloring Agents↗

The relationship between the number of sound, decayed, and filled permanent tooth surfaces and the number of sealed surfaces in children and adolescents.

OBJECTIVES: The purpose of this investigation was to determine the prevalence of sound, decayed, filled, and sealed permanent tooth surfaces for children and adolescents from three fluoridated communities in British Columbia and to develop a predictive model of sealant use that included the dental caries status of tooth surfaces. METHODS: Children in grades 2 and 3 (n = 2,715) and adolescents in grades 8 and 9 (3,317) were surveyed to determine the prevalence of sound, decayed, filled, and sealed permanent tooth surfaces. The DMFS index, modified to include incipient (D1) and cavitated (D2) lesions, was used to measure the status of all tooth surfaces. The prevalence of D1D2MF and sealed tooth surfaces was estimated by age group and tooth type. Logistic regression models were developed to analyze the association between a number of independent variables and sealant use. RESULTS: About 60 percent of surveyed students had one or more sealants present, with a mean of 3.2 sealants per subject. Of all pit and fissure surfaces on permanent first molars, 23.4 percent and 20.1 percent were sealed for the 11 years and younger and 12 years and older age groups, respectively. For these same two age groups, the percentages of pit and fissure surfaces that were decayed and filled were 6.7 percent and 19.7 percent, respectively. For both age groups combined, 10.8 percent and 23.7 percent of all pit and fissure surfaces on second molars and premolars, respectively, were sealed. The prevalence of decayed and filled pit and fissure surfaces was 5.6 percent and 1.8 percent, respectively, for second molars and premolars. Premolars were being sealed at a rate of 13 to 1 compared to the number of decayed and filled surfaces. Logistic regression failed to identify meaningful predictors of sealant use. CONCLUSIONS: Results from this study found an increase in the prevalence of sealants in the three communities surveyed, yet failed to identify criteria used by dentists or auxiliaries when making decisions about sealant placement. Professional education in the appropriate use of sealants may be necessary.

Adolescent↗

A comparison of the oropharyngeal leak pressure between the reusable Classic laryngeal mask airway and the single-use Soft Seal laryngeal mask airway.

We tested the oropharyngeal leak pressure with the reusable laryngeal mask airway and the single-use Soft Seal laryngeal mask airway. These two types of laryngeal mask airway (LMA) have a similar design but the reusable LMA cuff is made from silicone whereas the Soft Seal LMA cuff is polyvinylchloride. Thirty-five healthy subjects were anaesthetized and paralyzed and the two types of Soft Seal LMA were compared in a blinded randomized cross-over trial. The oropharyngeal leak pressure was significantly higher with the Soft Seal than the reuable (21 +/- 7.6 and 16 +/- 6.7 cm H2O respectively, P = 0.002). However, in four subjects the oropharyngeal leak pressure was higher with the reusable by > 4 cm H2O. We concluded that the reusable LMA may provide a better seal in some individuals but that, on average, the Soft Seal provides a higher oropharyngeal leak pressure than the reusable LMA.

Adult↗

The new perilaryngeal airway (CobraPLA) is as efficient as the laryngeal mask airway (LMA) but provides better airway sealing pressures.

The Laryngeal Mask Airway (LMA) is a frequently used efficient airway device, yet it sometimes seals poorly, thus reducing the efficacy of positive-pressure ventilation. The Perilaryngeal Airway (CobraPLA) is a novel airway device with a larger pharyngeal cuff (when inflated). We tested the hypothesis that the CobraPLA was superior to the LMA with regard to insertion time and airway sealing pressure and comparable to the LMA in airway adequacy and recovery characteristics. After midazolam and fentanyl administration, 81 ASA physical status I-II outpatients having elective surgery were randomized to receive an LMA or CobraPLA. Anesthesia was induced with propofol (2.5 mg/kg IV), and the airway was inserted. We measured 1) insertion time; 2) adequacy of the airway (no leak at 15-cm-H2O peak pressure or tidal volume of 5 mL/kg); 3) airway sealing pressure; 4) number of repositioning attempts; and 5) sealing quality (no leak at tidal volume of 8 mL/kg). At the end of surgery, gastric insufflation, postoperative sore throat, dysphonia, and dysphagia were evaluated. Data were compared with unpaired Student's t-tests, chi2 tests, or Fisher's exact tests; P < 0.05 was significant. Patient characteristics, insertion times, airway adequacy, number of repositioning attempts, and recovery were similar in each group. Airway sealing pressure was significantly greater with CobraPLA (23 +/- 6 cm H2O) than LMA (18 +/- 5 cm H2O, P < 0.001). The CobraPLA has insertion characteristics similar to the LMA but better airway sealing capabilities.

Adult↗

Laser stapedotomy: a comparative study of prostheses and seals.

During the past 13 years, a number of prostheses of differing design and tissue seals have been used in laser stapedotomy for otosclerosis. This study compares the results of three different configurations of prostheses and tissue seals in a series of 53 patients. In 19, a platinum wire Teflon piston was placed in the laser stapedotomy fenestra and crimped on the long process of the incus; autologous venous blood was infiltrated into the oval window niche as a sealing mechanism. In 8 patients, a stainless steel bucket-handle-type prosthesis was used with a blood tissue seal. In 26 patients, a segment of autogenous vein was clad onto the bucket-handle-type prosthesis and placed into the laser fenestra. Two tissue seals (blood and vein) were also compared. The results were compared with regard to several audiometric parameters. It would appear that the bucket handle/vein configuration improves air-bone gap closure in the low- and mid-frequency speech range and also shows an advantage for air-bone gap closure to 10 dB or less compared to the other configurations in this study. Mean postoperative gaps were significantly less for vein compared to the blood tissue seal. Physiologic and surgical implications are discussed, and the vein-clad technique is illustrated.

Adolescent↗

Influence of Er:YAG laser irradiation on apical sealing of four different sealers.

The sealing of the root canal system is of fundamental importance for successful endodontic treatment. To obtain an adequate apical seal, many factors must be considered such as the presence of smear layer and the sealer applied. After canal preparation, this layer must be removed because it prevents close contact between the dentinal walls and the sealing material. The goal of this study was to evaluate the sealing ability of four different sealers after smear layer removal with either 17% EDTA-T irrigation or Er:YAG laser irradiation of 46 teeth. The canals were sealed with four different sealers: Sealapex, Ketac Endo, AH Plus and N-Rickert. The method for smear layer removal did not influence apical sealing. AH Plus and N-Rickert allowed less dye leakage when compared to Sealapex and Ketac Endo.

Calcium Hydroxide↗

Influence of ensiling temperature, simulated rainfall, and delayed sealing on fermentation characteristics and aerobic stability of corn silage.

The aim of this study was to determine how delayed silo sealing, high ensiling temperatures, and rainfall at harvest affect the fermentation and aerobic stability of corn silage. One-half of each of 4 replicated, 6 x 1.5 m plots of a corn hybrid was harvested at 35% dry matter (Dry), and each of the other halves was harvested after they were sprinkled with sufficient water to simulate 4 mm of rainfall (Wet). Six representative (2 kg) subsamples were taken from the Wet and Dry forage piles and ensiled immediately (Prompt). Three hours later, 6 additional representative (2 kg) samples were taken from each pile and ensiled (Delay). Half of the bags from each moisture x sealing time treatment combination were stored for 82 d in a 40 degrees C incubator (Hot) and the other half were stored in a 20 degrees C air-conditioned room (Cool). A 2 (moisture treatments) x 2 (sealing times) x 2 (ensiling temperatures) factorial design with 3 replicates per treatment was used for the study. Wetting the corn silage increased concentrations of NH(3)-N, ethanol, and acetic acid. Ensiling at 40 instead of 20 degrees C increased pH, in vitro digestibility, and concentrations of NH(3)-N, residual water-soluble carbohydrates and acid detergent insoluble crude protein. The higher ensiling temperature also reduced concentrations of neutral and acid detergent fiber and lactic and acetic acid. Delayed sealing reduced concentrations of NH(3)-N and total volatile fatty acids. Wetting, high temperature ensiling, and delayed sealing each reduced yeast counts slightly, and marginally (8 h) increased aerobic stability. Hot-Wet-Delay silages were more stable than other silages but had the lowest lactic to acetic acid ratio, and total volatile fatty acid concentration. This study indicates that the fermentation of corn silage is adversely affected by wet conditions at harvest and high ensiling temperatures, whereas delayed silo sealing for 3 h caused no adverse effects.

Acetic Acid↗

[Mesh and glue technique as a new sealing technique for the use of expanded polytetrafluoroethylene dura substitute: the experimental studies of its tolerance for pressure and long-term histological changes].

Expanded polytetrafluoroethylene (ePTFE) as a dural substitute is sometimes associated with leakage of cerebrospinal fluid through the suture line. We have developed a new technique to seal the suture line with an absorbable mesh and fibrin glue. It is named as the mesh-and-glue technique. In this paper, the basic background of the efficacy of this technique was examined using in vitro and in vivo experimental models. The sealing effect was estimated on water leakage through 1 cm of suture line on the ePTFE sutured with 4-0 braided nylon at intervals of 2mm. The burst pressure of the non-sealed, conventional fibrin glue, simple glue spray, mesh-and-glue, and mesh-and-glue combined with spray was 2.8 +/- 0.4, 4.3 +/- 1.2, 64.4 +/- 21.4, 142.7 +/- 22.2 and 406.1 +/- 29.7 cm H2O respectively. It was worth noting that mesh-and-glue combined with the spray method can tolerate even arterial pressure. It was also observed that mesh-and-glue can seal a small dural defect. Long-term pathological changes of the mesh-and-glue was examined in a murine craniotomy model. Implanted mesh and fibrin glue was gradually transformed into a tight connective tissue firmly adhering to the surrounding structure within two months. These experimental results well support the clinical efficacy of the mesh-and-glue technique. This technique can also be applied to seal the arachnoid membrane after spinal surgery or to seal the suture line of arteriotomy in carotid endoarterectomy.

Animals↗

Psychometric validation of the French version of the side-effects and life satisfaction inventory (SEALS) in epileptic patients: comparison with the QOLIE-31 inventory and a generic quality of life questionnaire.

A psychometric evaluation of a French version of the side-effects and life satisfaction inventory (SEALS) was carried out. SEALS was compared to the quality of life in epilepsy-31 questionnaire (QOLIE-31) and a generic, health-related quality-of-life questionnaire, the Nottingham health profile (NHP). The psychometric properties of SEALS, assessed in 190 adult subjects with epilepsy, included: acceptability, test-retest reliability and validity, multitrait analysis including internal consistency and item-to-scale correlations, construct validity using factor analysis and discriminative validity using associations with disease characteristics and treatment effects, and, correlations with NHP and QOLIE-31 scores for convergent and divergent validity. Both acceptability and reproducibility were good and internal consistency was high (Cronbach's alpha coefficient = 0.92). Factor analysis with varimax rotation identified five factors: the first, related to cognitive function accounted for 26.0% of the variance. Discriminative validity was good for most treatment characteristics (tolerability, seizure control, compliance) and clinical features (epilepsy type, seizure frequency and severity, depressive symptoms). Correlations with the NHP and QOLIE-31 scores were consistently strong. It was concluded that the psychometric properties of the French translation of SEALS were similar to the original English version. In addition, SEALS provides information on quality of life that is complementary to that obtained with QOLIE-31. In particular, with respect to the QOLIE-31, the SEALS provides information on cognitive and neuropsychological aspects of impairment of quality of life, whereas the QOLIE-31 has a broader scope, taking into account multiple aspects of quality of life in epilepsy.

Adolescent↗

[Dimensional instability of zinc oxide-eugenol based temporary sealing materials used in endodontics].

The dimensional instability of temporary sealing materials based on zinc oxide-eugenol was studied in vitro by chemical reaction between an indicator solution (5% nickel sulfate) and a developing solution (1% alcohol dimethylglixime). Thermal cycling was performed (5, 37 and 60 degrees C). Zinc acetate was added to zinc oxide to test its action on dimensional instability. The materials were divided into two groups. 1) group with double sealing (gutta-percha + sealing material), and 2) group without double sealing. It was concluded that none of the temporary sealing materials tested, with or without double sealing, prevented marginal infiltration when submitted to thermal cycling. The addition of zinc acetate to zinc oxide was not effective in preventing marginal infiltration.

Acetates↗

[An empirical report on fissure sealing in private practice with a duration of up to 10 years].

This study reports a follow-up on 2415 occlusal sealings performed in a dental office. After nine to ten years service time, the survival rate of all sealed surfaces dropped to 69.5% because of either occlusal or interproximal carious activities. Retention of the sealings was intact in 91.5% after one year, but dropped to 58.2% after nine years. In the control group 49.3% of the grooves showed either caries or fillings during the last check-up whereas this occurred in only 7.3% of the sealed teeth (ratio 7:1). The difference among those two groups was even bigger (45.7% vs. 5%, ratio 9:1) when excluding all two-sided fillings. The costs of restoring one tooth surface in the control group was on average two to three times higher than for the sealings group. There is no doubt about the beneficial prophylactic effect of the use of sealants, even in the context of the private dental office, and no inconvenient side-effects have been found. The results concerning the retention rate of sealing in this study from a private dental office are comparable with the average of those reported in many papers from U.S. Dental Schools, they are even slightly better for the caries incidence.

Adolescent↗

Phylogenetic relationships within the eared seals (Otariidae: Carnivora): implications for the historical biogeography of the family.

Phylogenetic relationships within the family Otariidae were investigated using two regions of the mitochondrial genome. A 360-bp region of the cytochrome b gene was employed for the primary phylogenetic analysis, while a 356-bp segment of the control region was used to enhance resolution of the terminal nodes. Traditional classification of the family into the subfamilies Arctocephalinae (fur seals) and Otariinae (sea lions) is not supported, with the fur seal Callorhinus ursinus having a basal relationship relative to the rest of the family. This is consistent with the fossil record which suggests that this genus diverged from the line leading to the remaining fur seals and sea lions about 6 million years ago (mya). There is also little evidence to support or refute the monophyly of sea lions. Four sea lion clades and five fur seal clades were observed, but relationships among these clades are unclear. Similar genetic divergences between the sea lion clades (D(a) = 0.054-0.078), as well as between the major Arctocephalus fur seal clades (D(a) = 0.040-0.069) suggest that these groups underwent periods of rapid radiation at about the time they diverged from each other. Rapid radiations of this type make the resolution of relationships between the resulting species difficult and indicate the requirement for additional molecular data from both nuclear and mitochondrial genes. The phylogenetic relationships within the family and the genetic distances among some taxa highlight inconsistencies in the current taxonomic classification of the family.

Animals↗

Distribution patterns of polychlorinated biphenyl congeners in harbor seal (Phoca vitulina) tissues: statistical analysis.

Tissue samples from five harbor seals (Phoca vitulina) have been analyzed for coplanar and other polychlorinated biphenyl (CB) congeners, in order to measure variations in levels and patterns of the CBs. Blubber samples contained the highest levels of CBs in all animals; kidney and liver were relatively high-level tissues. CB-153 and CB-138 were the most abundant CB congeners in all samples analyzed. Variations in the patterns of CB congeners in tissues were studied by principal component analyses and multivariate analysis of variance. The CB congener patterns in seals from different geographical regions had distinctly different patterns, whereas the patterns appeared quite similar in tissues within each seal. Based on multivariate analysis of variance, it was, however, possible to detect some systematic variation of the principal components with individual seals and with tissue type within the seals. The assessment of differences in CB congener patterns was possible by comparison to results obtained by repeated analyses of a quality control sample. The calculated dioxin toxic equivalents of the CB congeners followed the levels of the CB congeners, with the highest levels being found in the blubber samples.

Animals↗