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At least 325 records · Page 18Linked to original sources
PubMed2001

Improving the seal of amalgam cores with cemented dowels: a comparative in vitro radioactive tracer study.

Amalgam cores with cemented dowels are commonly used to restore endodontically treated teeth. These restorations were widely studied for their mechanical properties; however, less is known about their sealing ability. The effect of the cement type used for the dowel and that of a bonding agent application were studied in a radioactive tracer coronal leakage study. The sealing ability of posts and cores was also compared with that of 5 mm remaining root canal fillings. Composite luting cement provided a better seal than zinc phosphate cement. The seal provided by 5 mm root canal fillings was poorer than that provided by posts and cores. High variability in seal quality was found among all types of posts and cores studied. This may indicate that the seal provided by cemented dowels with amalgam cores is unpredictable. Because neither the remaining root canal filling nor the post and core may be trusted alone for a seal, each should be performed with the greatest care and both covered with a crown as soon as possible.

Bicuspid↗
PubMedDate not supplied

Hydrogel tissue adhesive for sealing corneal incisions.

The purpose of the study was to assess the efficacy of a newly developed hydrogel tissue adhesive for sealing corneal incisions in ex vivo rabbit eyes. Simple through-and-through central linear corneal incisions measuring 1-5 mm were created in enucleated rabbit eyes. As controls, the leaking pressures were measured immediately after the incisions had been made. Afterwards, the incisions were sealed with hydrogel adhesive in group 1 and with a single 10-0 nylon suture in group 2. The leaking pressure of each incision was measured after the wounds had been sealed in both groups. The leaking pressures of the controls and the sealed incisions were compared for statistical significance using the Wilcoxon signed rank test. The difference between the leaking pressures before and after sealing the incisions in groups 1 and 2 were compared using the Mann-Whitney rank sum test. The leaking pressures were significantly higher after sealing in both groups 1 and 2 compared to the controls for all incision sizes. The differences in the leaking pressures before and after adhesive application were higher than before and after suturing in all incision sizes. The differences were all statistically significant except for the 1-mm incisions. We conclude that the hydrogel glue has the potential to be used for sealing corneal incisions measuring up to 5 mm.

Animals↗
PubMed2002

Suction vs water seal after pulmonary resection: a randomized prospective study.

STUDY OBJECTIVE: To evaluate whether suction or water seal is superior in the management of chest tubes after pulmonary resection. DESIGN: A prospective, randomized, controlled trial. After an initial, brief period of suction, patients were randomized to water seal or - 20 cm H(2)O suction. SETTING: University hospital. PATIENTS: Sixty-eight patients who underwent wedge resection, segmentectomy, or lobectomy were included in the study. Those patients who underwent reoperative surgery or lung volume reduction surgery were excluded. RESULTS: There were 34 patients in each group. The two groups were evenly matched for age, sex, operation performed, severity of lung disease, and nutritional status. Fifteen patients in each group (44%) had an air leak at the completion of surgery. The duration of the air leak was shorter in the water seal group than in the suction group (mean +/- SEM, 1.50 +/- 0.32 days vs 3.27 +/- 0.80 days, respectively; p = 0.05). The mean times to removal of chest tubes were 3.33 +/- 0.35 days in the water seal group and 5.47 +/- 0.98 days in the suction group (p = 0.06). The length of stapled parenchyma was measured for each patient and averaged 24.9 cm for the water seal group and 18.5 cm for the suction group (p = 0.18). When corrected for the length of staple lines, the duration of air leaks and days with chest tube were dramatically lower in the water seal group (p = 0.02 and p = 0.02, respectively). CONCLUSION: Placing chest tubes on water seal after a brief period of suction after pulmonary resection shortens the duration of the air leak and likely decreases the time that the chest tubes remain in place. Adoption of this practice may result in lower morbidity and lower hospital costs.

Aged↗
PubMed2001

Aerosol therapy with valved holding chambers in young children: importance of the facemask seal.

OBJECTIVE: Masks are an essential interface between valved holding chambers (VHCs), or spacers, and a small child's face for providing aerosol therapy. Clinical experience suggests that many young children do not cooperate with the VHC treatment or tolerate a mask of any kind. This might impair the mask-face seal and reduce the dose delivered to the child. The objective of this study was to evaluate the ability of parents to provide a good mask-face seal in infants and toddlers using 3 masks provided with commonly used pediatric VHCs and compare this with the seal obtained with the Hans Rudolph pediatric anesthesia mask. METHODS: A preliminary in vitro filter study was conducted to validate the assumption that reduced ventilation as a result of increased facemask leak reduces the drug aerosol dose delivered to the mouth. Facemask leak then was studied in vivo for NebuChamber, AeroChamber, BabyHaler, and Hans Rudolph masks by measuring ventilation with an in-line pneumotachograph while the facemask was held in place by experienced parents who were asked to demonstrate how they deliver medication to their children without any additional instruction. Thirty children (mean age: 3.2 +/- 1.4 years) performed 4 repeat studies with each mask. The first 10 patients performed the tests once again within 1 month. On the second occasion, the parents were coached continuously and encouraged to hold the mask tightly against the child's face. RESULTS: The AeroChamber and Hans Rudolph masks provided the best seal as reflected in the magnitude of the ventilation measured through them. The NebuChamber provided the poorest seal, with 45% less ventilation than the AeroChamber and Hans Rudolph masks. There was considerable intraindividual variability for all masks (24% to 48%); however, the variability with the NebuChamber mask was 2-fold greater than the other masks. All ventilatory volumes during the coached session were significantly greater than during the uncoached session. Variability during the coached session was significantly less (except for the BabyHaler, which remained unchanged). CONCLUSIONS: VHCs with masks designed for use with small children may provide a poor seal with the face, leading to reduced or more variable dose delivery. The facemask seal is critical for efficient aerosol delivery to infants and young children, and this should be stressed to parents.

Administration, Inhalation↗
PubMed1990

Static pressure seal of earmolds.

Four experiments were carried out to investigate the effect on the static pressure seal of earmolds made from currently used impression and earmold materials; the occasional practice of making more than one earmold from an impression; the earmoldmaker buildup of impressions; and the multistage buildup of impressions by the impression taker. Experiment 1 showed that the chance of sealing the ear with earmolds made by the ordinary two-stage technique with only general buildup of the impression was approximately 10 percent and that none of the impression or earmold materials significantly improved the chance of obtaining a seal. Experiment 2 showed that the chance of obtaining a seal with multiple earmolds made from the one impression was zero, or very close to zero. Experiment 3 revealed that the chance of obtaining a seal increased to 55 percent when the earmold was made from an impression which was specially built up by the earmoldmaker. Experiment 4 showed that the chance of sealing the ear with earmolds made from multistage impressions was significantly greater (87.5 percent) than sealing the ear with those made from impressions specially built up by the earmoldmaker.

Adult↗
PubMed1997

Voluntary programs: ADA Seal program and international implications.

For about 130 years the American Dental Association (ADA) has aided the profession and the public in selecting safe and effective dental products. Since 1930, dental products have been evaluated through the ADA Seal program. In accordance with the ADA's Bylaws, the Council on Scientific Affairs assesses information evaluating the safety, efficacy, appropriate use, and promotional claims of dental products. In doing so, the Council may award the ADA's Seal of Acceptance. In collaboration with interested parties, expert consultants, and Council members, the ADA produces guidelines suggesting appropriate methodologies and submission data to assist manufacturers in voluntarily earning the Seal of Acceptance. To date, numerous professional and consumer products have been evaluated, and about 1,300 of these products bear the Association's Seal of Acceptance. When a product is awarded the Seal it means that adequate data have been submitted and reviewed and, based on available information, the product meets ADA guidelines of safety and effectiveness. Dental health care professionals and consumers who use products that have the Seal can be confident that a product's properties and performance are consistent with current professional standards and manufacturers' claims. The ADA Seal program serves to help dentists and manufacturers meet their ethical obligations to the public by promoting safe and effective health care products.

American Dental Association↗
PubMed2001

A lip seal study of Japanese children with malocclusion.

The purpose of this study was to clarify the relationship between lip seal and malocclusion in Japanese children. Fifty-three patients aged 7 to 14 years (mean 10.24 +/- 1.93) were selected randomly, and compared with 20 subjects with normal occlusion aged 7 to 14 years (mean 10.50 +/- 2.56). The subjects were divided into a good lip seal group and poor lip seal group by observing the distance between the upper and lower lip at rest. The variables that were analyzed for morphological evaluation included model analysis and cephalometric analysis. Noted for functional evaluation were tongue position, the size of the tonsils and adenoids and the oral muscle force measured by button pulling. In the evaluation of the degree of lip seal, there was no statistical difference between subjects with malocclusion and those with normal occlusion. Within the group with malocclusions, however, there were significant differences in overbite (p < 0.01), overjet (p < 0.01), and oral muscle force by button pulling (p < 0.05) between the good lip seal and poor lip seal groups. These results suggest that there is a need not only to correct malocclusion but also to be aware of lip sealing so that it may be improved in Japanese children.

Adolescent↗
PubMed1992

Cariostatic and ultraconservative sealed restorations: six-year results.

The objective of this clinical study was to determine the ability of an ultraconservative, sealed composite resin restoration, without a traditional cavity preparation and without the removal of the carious lesion, to arrest Class I caries. Tooth preparation was limited to placing a bevel in the enamel. These restorations were compared, over 6 years, with (1) ultraconservative, localized, sealed amalgam restorations with no extension for prevention and (2) traditional, unsealed amalgam restorations with the usual extension for prevention outline form. Caries was arrested by the ultraconservative, sealed composite resin restorations for 6 years. Complete sealant retention on the sealed amalgam restorations was somewhat lower than that on the sealed composite resin restorations; conversely, partial sealant retention was higher for the sealed amalgam group. The marginal integrity of the sealed amalgam restorations was significantly superior to that of the unsealed amalgam restorations. The sealant also protected Class I posterior composite resin restorations against wear.

Adolescent↗
PubMed1992

Clinical trial of junction seals for the prevention of urinary catheter-associated bacteriuria.

BACKGROUND: Preconnected catheter systems with sealed junctions have been associated with reduced rates of bacteriuria and mortality. A clinical trial was undertaken to evaluate the effectiveness of a junction seal applied after catheter insertion for preventing bacteriuria and reducing mortality. METHODS: Patients undergoing transurethral catheterization at a community hospital were randomized within 24 hours of catheter insertion to receive either a tape seal applied to the catheter-drainage tubing junction or no tape seal. Catheter urine cultures and catheter care violations were monitored daily until catheter removal or patient discharge. RESULTS: Overall, 124 (13.7%) of 903 patients in the group receiving a junction seal acquired bacteriuria, compared with 125 (14.9%) of 837 patients in the control group (P = .52, odds ratio = 0.91, 95% confidence interval, 0.69 to 1.20). Multivariate analysis revealed that only female gender and lack of systemic antibiotic use independently correlated with the development of bacteriuria; neither junction treatment randomization nor disconnection of the junction was associated with bacteriuria. Survival curve analysis of patients stratified by gender and antibiotic use revealed no significant differences in the rate of bacteriuria between treatment groups. The overall mortality in the tape seal group was less than that in the control group (6.6% vs. 8.0%, respectively), but not to a statistically significant extent despite stratification by antibiotic use. CONCLUSIONS: The use of a tape seal applied to the catheter-drainage tubing junction within 24 hours of catheter insertion was not associated with significantly lower rates of bacteriuria and mortality in patients undergoing short-term catheterization.

Bacteriuria↗
PubMed2004

Superiority of water application to water sealing in burn wound healing.

BACKGROUND: Recently there have appeared on the market many external dressings for wound management. They all use water-sealing materials to maintain wounds in a moist state. However, in our daily clinical observations, a water-sealing material sometimes results in poor wound healing. Although a water-sealing material does in fact keep the wound moist, the quality of the water is far from that of the optimum extracellular fluid. METHODS: A second-degree burn wound was made in the rat by contact with a metal stick. Experiment 1 was to evaluate the influence of delayed primary wound treatment on burn-wound depth progression. We used a time lag procedure. Each group was treated with a water-sealing application (hydrocolloid sheet). Experiment 2 was to investigate the progression-preventing effect of normal saline on a burn allowed to dry for 3 hours, we compared a group that received a water sealing (non-moistening and incomplete moisture) dressing with one that received a water-supplying (moistening) dressing with using chi-square test. RESULTS: In the Experiment 1 (time lag and water sealing test), the early group showed quite normal wound healing at 7 days after onset. The slough was thin (about 10-20% of full dermal thickness). The delayed groups showed the poor healing characteristic. The slough was relatively thick (about 30-60% of full dermal thickness). Three hours' delay seemed to bring about poor healing. In the Experiment 2 (water application test), the moistening (water application) group showed relatively good healing after seven days. The slough was as thin as in the early group in the Experiment 1. The non-moistening group showed a poor healing process like the delayed group in the Experiment 1. For the moistening group, the healing percentage of 77.8% was significantly greater than the 41.3% observed in the non-moistening group (chi-square test, p < 0.05). CONCLUSIONS: All the materials in wound dressing are water-sealing. When the component water under the sheet is far from the extracellular fluid, these applications bring about poor healing. Delayed application and incomplete moisture should be corrected by external water-application.

Animals↗
PubMed1990

Evaluation of a fissure sealing programme in a Danish Public Child Dental Service.

Most studies on fissure sealants have been conducted as explanatory trials. The present study takes a pragmatic approach to the use of fissure sealing as a caries-preventive measure. The study was conducted in two municipalities in the Copenhagen area, one (S) with a policy of sealing all occlusal fissures of first permanent molars and another (C) where fissure sealing was not used. The study included all the 1053 12-year-old children in the two municipalities who had participated in the dental service since preschool age. Fissure sealing with Delton(R) was performed as soon after eruption as possible. Out of 2180 first permanent molars in S, 1721 (79 per cent) were sealed. An overall complete retention rate of 40 per cent was obtained after the 6- to 7-year observation period. The caries prevalence on all types of surfaces not sealed was almost identical in both municipalities, supporting the assumption that they had similar caries levels. On the target surfaces the mean caries increment for girls was 1.4 and for boys 1.2 in S compared with 2.0 (girls) and 1.6 (boys) in C, giving an effectiveness in caries reduction of 32 and 25 per cent for girls and boys respectively. For girls, 5 occlusal surfaces had to be sealed in order to save one filling; compared to 8 surfaces for boys.

Child↗
PubMedDate not supplied

Computer interface for vial sealing force measurements.

The force applied to the closure of a parenteral container is a critical parameter in assuring the integrity of a seal. Measurement of the force can be accomplished either off line, through residual force measurements, or on line, through instrumentation of the sealing station. The instrumentation of the sealing station provides a dynamic profile of the sealing event for development of the optimal sealing parameters. A computer interface for this application has been developed using a standard IBM-AT and commercially available data acquisition hardware and software. The resultant data can be set up in Lotus 1-2-3, or any other analysis package capable of importing ASCII files, for graphic display, and/or additional analysis. The system thus provides a means to acquire quantitative data on the sealing event for development of optimal sealing parameters.

Drug Packaging↗
PubMed1989

[Study of pit and fissure sealants. The effect of viscosity of the sealants and type of the applicators on the administration time and the sealed area].

From the standpoint of the durability of the sealants, it is assumed that the sealants should be applied only to the bottom part of the pit and fissure to avoid marginal fracture and wear of the materials. Because of this, a minimum area for the sealant to be applied is required for a stable prevention of dental caries. The purpose of this study was to investigate the effect of viscosity of the sealants and various applicators in the techniques for minimum-area-sealing. Three sealants with various degrees of viscosity were applied to the stone models of a lower first molar by means of four types of applicators. Three operators conducting the experiment were a dentist with two years of experience, a dentist with one year of experience and a student. The time required for administration and the area of sealed pits and fissures were evaluated. The following results were obtained. 1. The sealants with a lower degree of viscosity revealed a shorter administration time and a narrower sealed area. 2. The applicators with thinner nozzles brought about a shorter administration time and a narrower sealed area. 3. The administration time did not exhibit significant differences among the operators, while the sealed area exhibited significant differences. 4. The longer the period of the clinical experience of the operator, the narrower the sealed area obtained. From the above results, it is recommended to select a sealant with low viscosity and utilize an applicator with a thin nozzle or a brush with a fine tip to obtain the minimum-sealing-area. Additionally, prior to the clinical trial, one should become acquainted with the characteristics of the sealant as well as the manipulation of the applicator.

Pit and Fissure Sealants↗
PubMed1997

Marginal seal composition in amalgam restored teeth of varying marginal leakage.

An in vitro study was performed to ascertain the marginal seal elemental composition of amalgam restored extracted teeth of known marginal leakage. Occlusal cavities were cut in 400 caries free extracted teeth and left unlined or lined with one of 5 bases. A varnish was applied to half the cavities followed by restoration with a low copper or high copper amalgam to produce 20 restoration combinations. The teeth were stored in 1 per cent NaCl and thymol for 3 and 12 months at 20 degrees C whereafter a standard fluorescent dye marginal leakage test was performed on 320 specimens (eight teeth per treatment). Restoration combinations were grouped into 4 seal classes depending on percentage marginal seal achieved for each combination: 0-25 per cent; 26-50 per cent; 51-75 per cent and 76-100 per cent. The 80 remaining teeth (2 teeth per treatment) were fractured to expose the restoration and cavity surface, covered with marginal seal material and this was analysed by energy dispersive X-ray analysis. Elemental seal composition was compared to percentage marginal seal achieved using ANOVA and Tukey's test with significance set at p < 0.05. Numbers of elemental analysis specimens falling into each marginal seal class was 0-25 per cent = 48; 26-50 per cent = 18; 51-75 per cent = 10; 76-100 per cent = 4. Of the 16 elements detected, nine were significantly linked to sealing/leakage: Ca, Cl, Cu, Mg, Hg, P, Ag, Sn and Zn. The findings have a bearing on the improved longevity of amalgam restorations.

Analysis of Variance↗
PubMed1987

Histological, histochemical, and fine structural observations on the spleen of seals.

Spleens of three species of Antarctic seals with different diving habits (Weddell seal, crabeater seal, and fur seal) have been studied with histological, histochemical, and electron microscopic methods. The spleens can be classified as nonsinusoidal, with capsule and trabeculae rich in innervated smooth muscle cells. The trabecular system is particularly well developed in the deep- and long-diving Weddell seal. As in other mammals the pulp can be divided into white and red pulp. In the white pulp, periarteriolar lymphatic sheaths and secondary lymphatic nodules occur; both are surrounded by a marginal zone rich in macrophages and eosinophils. The nodules can be observed frequently, which is in accordance with abundance of plasma cells in the red pulp. Well-developed white pulp and numerous plasma cells and eosinophils obviously reflect a high load of nematodes, which have mainly been found in lung and stomach. Additionally, in the red pulp morphological evidence for the following functions has been found: destruction of erythrocytes, erythropoiesis, and thrombopoiesis. In respect to blood flow through the red pulp, we interpret our observations in the following way: terminal branches of arterioles open into the space between the fibroblastic reticulum cells; blood draining from here is collected into pulp veins, which are mainly found near the trabeculae. Thus, the seals have an open vascular compartment in their spleens, as also occurs in the cat. The red pulp is innervated by numerous nerve fibers that seem to include both cholinergic and adrenergic ones. The target cells of these fibers seem to be the fibroblastic reticulum cells, whose state of contraction may influence the direction of blood flow through the red pulp.

Animals↗
PubMed2003

Temporal trends of persistent organochlorine contamination in Russia: a case study of Baikal and Caspian Seal.

To examine temporal trends of organochlorine (OC) contamination in Lake Baikal and the Caspian Sea, concentrations of persistent OCs, such as DDT and its metabolites (DDTs), polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCHs), chlordane compounds (CHLs), tris(4-chlorophenyl)methane (TCPMe), and tris(4-chlorophenyl)methanol (TCPMOH), in the blubber of female seals were determined. Collections were made in 1992, 1993, 1995 and 1998. DDT concentrations in Baikal and Caspian seals showed a rapid decline during 1992 to 1998, while the concentrations of PCBs declined slowly. Elevated concentrations of HCHs were found in Caspian seals and there was no decline in their concentrations during 1993 to 1998, which could be due to extensive usage of HCHs around Caspian Sea in recent years. Trends of TCPMe and TCPMOH residues in Caspian seals were similar to that of DDTs. The pattern of PCB isomers in both Baikal seals and Caspian seals exhibited little temporal variations. Concentrations of non- ortho coplanar PCBs have declined at a faster rate than those of mono- ortho congeners. Compilation of available data on OC contamination in the North Pacific, Antarctic, Caspian Sea, Lake Baikal, and India suggested that the time trend of residues of contaminants during the 1990s were different among these regions. Residue levels of OC insecticides have declined slowly while PCBs remained at a steady state in the open oceans and the Antarctic. The magnitude of temporal variation in Lake Baikal seemed to be higher than that in the Caspian Sea. Residue concentrations of OCs have increased in Ganges River dolphins from 1989-92 to 1994-96, suggesting that tropical, developing countries are potential emission source of OCs.

Adipose Tissue↗
PubMed2002

Melatonin is rhythmic in newborn seals exposed to continuous light.

We have investigated the effect of continuous light and darkness on plasma levels of melatonin in relation to the extremely large and active pineal gland typically found in newborn seals. Plasma levels of melatonin in captive newborn harp (Phoca groenlandica) and hooded seals (Cystophora cristata) were generally extremely high, with peak concentrations ranging from 0.8 ng/ml to 62.3 ng/ml. Moreover, plasma melatonin showed a similar, pronounced rhythmicity, both outdoors under natural light conditions (hooded seal only) and indoors under either 30 h of continuous light (490 lux) or 30 h of darkness (0 lux). In all animals, the melatonin rhythm was closely associated with the outdoor light-dark cycle. We suggest that the melatonin rhythmicity in newborn seals is mainly under circadian control and that it originates by maternal influence in the foetus. Daytime plasma concentrations of melatonin were also measured in foetal hooded seals and their mothers. The foetal melatonin level was similar to daytime levels in newborns and was about five times higher than in their mothers, which indicates a significant flow of foetal melatonin to the mother. We speculate that the large pineal gland and high melatonin levels in the newborn seals are temporary consequences of a foetal strategy to affect the maternal blood supply during diving.

Animals↗
PubMed2005

Variation in the fatty acid composition of blubber in Cape fur seals (Arctocephalus pusillus pusillus) and the implications for dietary interpretation.

Analysis of the fatty acid (FA) composition of blubber is a valuable tool in interpreting the diet of marine mammals. This technique is based on the principle that particular FA present in prey can be incorporated largely untransformed into predator adipose tissue stores, thereby providing biochemical signatures with which to identify prey species. Several studies of phocid seals and cetaceans have documented vertical stratification in the FA composition of blubber such that inferences about diet may vary greatly depending on the layer of the blubber that is analysed. It is not known whether blubber in otariid seals (fur seals and sea lions) also displays vertical stratification in FA composition. Furthermore, it is not known whether the FA composition of blubber is uniform in these species. In the present study, the vertical and regional variation in FA composition of blubber was investigated in seven adult female Cape fur seals (Arctocephalus pusillus pusillus). The proportion of monounsaturated fatty acids (MUFA) was greater in the outer (43.6+/-1.3%) than inner portion (40.9+/-1.2%; t(20)=5.59, P<0.001) whereas the proportions were greater in the inner than outer portions for saturated fatty acids (23.6+/-0.5% and 21.9+/-0.6%, respectively, t(20) = 5.31, P<0.001) and polyunsaturated fatty acids (PUFA, 35.5+/-0.7% and 34.5+/-0.7%, respectively, t(20) = 3.81, P < 0.001). There was an inverse relationship between MUFA and PUFA in the blubber, independent of sampling location. In addition, with the exception of the inner portion from non-lactating females, blubber from the mammary area had the highest proportions of 18:1omega9c and total MUFA, followed by blubber from the rump and neck, suggesting that the deposition and mobilisation of blubber lipids may not be uniform around the body in otariid seals. These results support the need for blubber tissue to be sampled from the same site on animals, and to the full depth of the blubber layer, to minimise variation in FA profiles that could occur if different sites and depths were sampled. Such standardisation of sampling will further aid in interpreting diet in otariid seals using the FA Signature Analysis approach.

Adipose Tissue↗