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At least 775 records · Page 43Linked to original sources
PubMed2004

Effect of nonvital bleaching with 10% carbamide peroxide on sealing ability of resin composite restorations.

AIM: To (i) determine the effect of nonvital bleaching with 10% carbamide peroxide on the sealing ability of resin composite restorations bonded with a self-etching adhesive system; and (ii) compare the effects of antioxidant treatment and delayed restoration after bleaching on marginal seal. METHODOLOGY: Forty-eight noncarious maxillary incisors were divided into four groups (n=12) after conventional root canal treatment was completed. In group 1, access cavities were restored with a self-etching adhesive system and resin composite. In the remaining three groups, 10% carbamide peroxide bleaching gel was placed into the access cavities for periods of 8 h per day for 1 week. They were then restored in the same manner as group 1. Group 2 consisted of specimens restored immediately after bleaching. Group 3 specimens were treated with the antioxidant, 10% sodium ascorbate, whereas group 4 specimens were immersed in artificial saliva for 1 week before restoration. Ten specimens in each group were then subjected to dye leakage; the remaining 2 specimens were examined in a SEM (Jeol/JSM 5200, Tokyo, Japan). The dye penetration was assessed with the standard scoring system. Statistical analysis was carried out using the Kruskal-Wallis and the Mann-Whitney tests. RESULTS: Groups 1, 3 and 4 exhibited similar leakage patterns and significantly less leakage than group 2 (P<0.0083). SEM examination of groups 1, 3 and 4 specimens demonstrated close adaptation of resin composite to cavity walls, whereas group 2 specimens did not. CONCLUSION: Nonvital bleaching with 10% carbamide peroxide adversely affected the immediate sealing ability of resin composite restoration; both 10% sodium ascorbate treatment and a 1-week delay in restoration following bleaching improved the reduced sealing ability of resin composite.

Antioxidants↗
PubMed2006

The influence of root canal shape on the sealing ability of two root canal sealers.

AIM: To evaluate the influence of root canal form on the sealing ability of two root canal sealers. METHODOLOGY: Twenty radiographically confirmed straight and 20 curved root canals were prepared with a stepback hand filing technique. Root canal aberrations created during preparation were determined by the use of double exposure radiographic technique. The prepared canals were filled with lateral condensation of gutta-percha and one or other of two root canal sealers (Pulp Canal Sealer and Sealapex). Leakage along the apical 10 mm of roots was measured with a fluid transport model at 1, 3, 6, 9 and 12-month intervals. RESULTS: There were no statistically significant differences between straight and curved root canals (P > 0.05) for prevalence of root canal transportation. The prevalence of apical transportation was 80% in the straight and 85% in the curved root canals. A complete seal was more frequently observed in straight canals compared with curved canals. Utilizing the pi* index, analysis showed the filling with Sealapex allowed more leakage than Pulp Canal Sealer at 1 year. CONCLUSION: Under the conditions of the study, root canal form influenced short-term sealing ability. In the long-term the seal was affected by the sealer rather than root canal form.

Analysis of Variance↗
PubMed1993

Sleep in the harp seal (Pagophilus groenlandica). Comparison of sleep on land and in water.

Four young harp seals (aged three to five months) were implanted with electrodes for recording electrocorticograms (ECoG) of the two hemispheres, and electrocardiogram, electroculogram, and electromyogram of the neck muscles. In all the seals ECoG slow waves developed simultaneously in both hemispheres, irrespective of whether they slept on land, on the water surface or submerged. Slow-wave sleep (SWS) was present in animals on the water surface and submerged, while paradoxical sleep (PS) occurred only when the animals were submerged. Breathing in SWS could be both regular (pauses less than twenty seconds) and intermittent (pauses lasting up to three minutes alternating with hyperventilation periods). All the PS episodes occurred during single respiratory pauses and ended by waking while the seal ascended to the water surface to breathe. Flipper movements were sometimes observed in SWS, but never in PS. The ability of harp seals to cease respiration during sleep and to sleep under water could be an adaptation to living conditons in the freezing seas.

Journal Article↗
PubMed2004

On the structure of the adrenal gland of the common seal (Phoca vitulina vitulina).

The adrenal gland is a vitally important endocrine gland that occupies a central role in the regulatory mechanisms of the body metabolism. Environmental stress factors lead to permanent strain and overload of the body resulting in structural alterations of the adrenals that in turn are followed by hormonal imbalances. This leads to an increased susceptibility to bacterial and viral diseases. The recurrence of numerous fatalities in the different seal populations of the North Sea (during the years 1988, 1989 and 2002), of the Baikal Lake and Caspian Sea (during the years 2000 and 2001) were the motive for a morphological investigation of the species-specific structure of the adrenal gland of the common seal in order to differentiate environmental stress-induced pathological alterations from the physiological structure of this organ. The study was based on adrenals of 112 common seals (Phoca vitulina vitulina) using light microscopic and transmission and scanning electron microscopic methods. The phocine adrenal gland displays several structural characteristics. Originating from the connective tissue organ capsule, narrow and broad septa intersperse the adrenal cortex. These septa contain blastemata as a reserve for the regeneration of hormone-producing cortical cells. Such blastemata are also occurring in the form of an intermediate zone in between the zona glomerulosa and zona fasciculata in the phocine adrenal cortex. Another species-specific characteristic is an inverse part of the adrenal cortex encircling the central vein of the organ. These structural features have to be considered in assessment and definition of pathological alterations of the adrenals as observed in the form of exhausted blastema cell pools in the adrenocortex of seals perished in the mentioned phocine mass mortalities.

Adrenal Glands↗
PubMedDate not supplied

Evaluation of a vessel-sealing device for small intestinal resection and anastomosis in normal horses.

OBJECTIVES: To compare arterial bursting pressure after vessel closure using a vessel-sealing device (LigaSure Atlas Laparoscopic Sealer/Divider Instrument; Valleylab, Boulder, CO), a ligate-and-divide stapling device (LDS), and 2-0 polydioxanone suture. To evaluate the LigaSure Atlas as a method for ligation of the mesenteric vasculature during small intestinal resection in normal horses. STUDY DESIGN: Experimental study. ANIMALS: Part A: jejunal segments from 19 horses. Part B: 6 horses, aged 1 to 18 years, weighing 330 to 509 kg. METHODS: Part A: Jejunal segments with mesenteric vessels were collected from 19 horses. After closure by 1 of 3 methods (LigaSure Atlas, LDS, 2-0 polydioxanone) arteries were cannulated, and bursting pressure was measured by incrementally increasing intraluminal pressure until failure. Part B: Six horses had jejunal resection and anastomosis using a vessel-sealing device (LigaSure Atlas) to provide hemostasis of the mesenteric vasculature. Horses were monitored clinically for 4 weeks. RESULTS: Part A: Mean +/- SEM bursting pressure after 2-0 polydioxanone ligation (1,014.50 +/- 279.05 mm Hg) was significantly greater than mean bursting pressure after LigaSure (554.25 +/- 228.79 mm Hg), which was significantly greater than the mean bursting pressure after LDS (373.25 +/- 183.69). Part B: No major operative or postoperative hemorrhage occurred after application of the LigaSure Atlas for sealing and transecting mesenteric vasculature during small intestinal resection in normal horses. CONCLUSIONS: The LigaSure Atlas appears to be a safe method for hemostasis of the mesenteric vasculature during small intestinal resection in normal horses. CLINICAL RELEVANCE: Benefits of the LigaSure Atlas vessel-sealing device include reduced time required to provide hemostasis, acceptable arterial bursting pressure, no remaining foreign material, and no risk for ligature slippage. In our experience, use of the LigaSure Atlas during small intestinal resection and anastomosis in horses is safe for ligation of vessels less than or equal to 7-mm diameter.

Anastomosis, Surgical↗
PubMed1984

Fissure sealing of permanent first molars in children receiving a high standard of prophylactic care.

The efficiency of sealing the occlusal fissures of permanent first molars was studied in a group of patients 6-9 yr of age receiving a high standard of prophylactic care. Very soon after the eruption one of the teeth in a homomaxillary pair was sealed, and the contralateral was used for control. The control teeth were painted with a fluoride varnish (Duraphat) every 6 months during the trial. 210 sites in 121 children were sealed and followed for a mean observation period of 23 months. At the end of the study, the retention rate was 62.9%, the percentage of effectiveness 24.2%, and the net gain 7.1%. The dmft index (primary molars and canines) was recorded for each patient at the time sealing was performed. A relationship between the caries prevalence in the primary teeth and the susceptibility for fissure caries in the control teeth was found. Effectiveness and net gain was highest in the group of children with 3-6 dmft.

Child↗
PubMed1976

Pulpal reactions to surface-sealed silicate cement and composite resin restorations.

The effect of surface sealing and presence of bacteria in connection with pulpal response to silicate cement and composite resin restorations was tested in monkey teeth. Surface-sealing of silicates reduced the pulpal reactions to this material, whereas no such effect was observed when composites were sealed. Bacteria regularly occurred on the cavity walls except underneath zinc oxide/eugenol (ZOE) fillings and when silicates were sealed with ZOE. The frequency of bacteria was higher in teeth with unacceptable pulpal responses (44 of 49) than in teeth with acceptable reactions (48 of 79).

Animals↗
PubMed1995

Longitudinal evaluation of sealing molars with and without incipient dental caries in a public health program.

OBJECTIVES: This study undertook a retrospective evaluation of the effect of sealants on the caries experience of initially sound and incipient permanent first molar pit and fissure surfaces. METHODS: Records of children with complete five-year records were obtained from a school-based dental sealant program in a fluoridated community. Sealants were placed on 677 tooth surfaces in 96 children; 120 tooth surfaces in 17 children who received baseline examinations were not sealed because of lack of caregiver consent. Tooth surfaces were initially diagnosed as being sound or having incipient lesions, and evaluated for caries status after five years. RESULTS: For initially incipient surfaces the five-year decay rate was 10.8 percent (41 of 380 surfaces) for sealed surfaces and 51.8 percent (29 of 56 surfaces) for nonsealed surfaces with an odds ratio of 8.88 (95% CI = 4.56, 17.35). Initially sound surfaces had a decay rate of 8.1 percent (24 of 297 surfaces) for sealed surfaces and 12.5 percent (8 of 64 surfaces) for nonsealed surfaces with an odds ratio of 1.63 (95% CI = 0.63, 4.08). The two odds ratios were significantly different. CONCLUSIONS: Initially sound tooth surfaces were unlikely to become decayed in five years, and did not benefit greatly from the application of sealants. Within the limitations of this study, there were clear efficiencies in sealing incipient, but not sound, surfaces. The targeting of teeth with incipient caries for sealants is therefore recommended.

Bisphenol A-Glycidyl Methacrylate↗
PubMed2005

Sealing effectiveness of materials used in furcation perforation in vitro.

OBJECTIVES: In this study the sealing ability of various materials used to repair furcation perforations was evaluated. DESIGN: Ninety human molars were endodontically treated and a perforation was made in the pulp chamber floor using a round bur. The teeth were inserted into a moistened flower sponge and perforation sites were sealed with one of the following materials: Mineral Trioxide Aggregate (ProRootM), Super-EBA, Vitremer, Hemarcol together with Super-EBA, Hemarcol together with Vitremer, Tricalcium phosphate together with AH26, Cavit W and amalgam. After eight months, the sealing effectiveness of the materials was evaluated in a double-blinded trial under a video-microscope by detecting the penetration of silver nitrate solution (50%w/w) in longitudinal tooth sections. RESULTS: Perforation sites filled with Hemarcol together with Vitremer or with MTA exhibited statistically less silver stain penetration while Cavit W or Tricalcium phosphate together with AH26 sealer failed to effectively seal the perforation sites. CONCLUSIONS: MTA alone or Vitremer in combination with a collagen sponge can be used effectively in the treatment of perforations in a furcation area.

Aluminum Compounds↗
PubMed1970

Ethylene oxide resistance of nondesiccated and desiccated spores of Bacillus subtilis var. niger hermetically sealed in various polymeric films.

The resistance to destruction of spores of Bacillus subtilis var. niger hermetically sealed in various polymeric films and exposed to ethylene oxide with and without relative humidity was determined. The effect of desiccation was also determined. The order of increased resistance to sterilization with regard to type of polymeric film was found to be: polyethylene equal to polyvinyl chloride, less than nylon, less than cellophane/polyethylene laminate, less than phenoxy, less than mylar/polyethylene laminate. Desiccated spores sealed in various polymeric films were much more resistant to ethylene oxide sterilization than nondesiccated spores. Relative humidity was an important factor in ethylene oxide sterilization with spores not sealed in polymeric films. However, with spores hermetically sealed in polyethylene, added relative humidity was an insignificant factor in the sterilization process.

Bacillus subtilis↗
PubMed1990

Sealing of the round window reversibly affects auditory brainstem response latencies.

The round window (RW) niche was sealed in 12 adult female albino Sprague-Dawley rats. Electrophysiological auditory function was measured with a computerized auditory brainstem response (ABR) recording technique, using 1- and 6 kHz stimuli. ABR measurements were performed prior to closure of the niche, immediately after the sealing, and 4 h, 24 h and 7 days later. After sealing, the latencies elicited by a 6 kHz stimulus increased, but returned to normal between 24 h and 7 days after closure. Stimulation with 1 kHz did not influence the latencies in such a clear-cut manner as when using 6 kHz. It is conceivable that sealing of the RW deprives a minor fraction of oxygen supplied to the basal part of the cochlea through the RW membrane, a procedure which by us is monitored as transient electrophysiological changes.

Animals↗
PubMed1992

Failure of expression of the phenobarbital-induced enhancement of UDP-glycosyltransferases in native, sealed endoplasmic reticulum vesicles from rat liver.

Conflicting data have been published regarding the effects of phenobarbital treatment on bilirubin UDP-glucuronyltransferase activity in native liver microsomes. Recent evidence suggests that the bilirubin UDP-glycosyltransferase system faces the interior of microsomal vesicles, and that expression of its activities in sealed microsomes may be rate-limited by transport of UDP sugars across the membrane. These observations raise the possibility that the reported variability in the effects of phenobarbital may reflect differences in integrity of the membrane in microsomal preparations. We examined the effect of phenobarbital on bilirubin UDP-glucosyltransferase and the UDP-glucuronyltransferase activities towards bilirubin, 4-nitrophenol, and 1-naphthol using native rat liver microsomes with verified vesicle integrity. Phenobarbital-induced microsomes in which the membrane permeability barrier was eliminated by pretreatment with detergent displayed markedly higher UDP-glycosyltransferase activities towards all tested substrates compared with activities in similarly disrupted microsomes from untreated rats. In contrast, none of the transferase activities tested were significantly enhanced by phenobarbital treatment when the enzymic activities were assayed in sealed microsomes. Addition to the enzyme assay mixture of UDPGlcNAc, a presumed physiological activator of the UDP-glucuronyltransferases, failed to expose the enhanced UDP-glucuronyltransferase concentration in phenobarbital-induced sealed microsomes. Our findings are consistent with the idea that transport of UDP sugar across the membrane may be rate-limiting for expression of UDP-glycosyltransferase activities in sealed microsomes. Quantitative assessment of membrane integrity is an essential prerequisite in experiments designed to study the regulation of the microsomal UDP-glycosyltransferase system.

Animals↗
PubMed2005

A modified chondroitin sulfate aldehyde adhesive for sealing corneal incisions.

PURPOSE: To compare a modified chondroitin sulfate aldehyde adhesive with standard sutures for sealing corneal incisions. METHODS: A keratome knife was used to create non-self-sealing, uniplanar, 3-mm, clear corneal incisions in enucleated rabbit eyes (n = 18). The wounds were sealed with either a chondroitin sulfate-aldehyde adhesive (n = 8), three 10-0 nylon sutures (n = 5), or one 10-0 nylon suture (n = 5). Wound stability was tested by filling the globes with balanced salt solution through an anterior chamber port and slowly increasing the IOP. The pressure changes were monitored with a digital manometer connected to the anterior chamber, and leak pressure was recorded for each eye. Confocal microscopy was performed on the glued eyes, to document the glue distribution along the wound. RESULTS: The mean leak pressures in the single-suture and three-suture subgroups were 26.4 +/- 6.0 and 44.3 +/- 8.2 mm Hg (SD), respectively. The maximum IOP achieved in eyes that received the glue was 104.7 mm Hg with a mean of 101.4 +/- 3.2 mm Hg. None of the eyes in which glue was used showed leakage. At confocal microscopy, the glue was distributed inside the wound edges as a homogeneous thin layer of a less dense signal than that of the stroma. CONCLUSIONS: A novel chondroitin sulfate-aldehyde adhesive was shown to be effective ex vivo for sealing corneal incisions in rabbit eyes and was superior to sutures for this purpose.

Aldehydes↗
PubMed1998

PYK2 in osteoclasts is an adhesion kinase, localized in the sealing zone, activated by ligation of alpha(v)beta3 integrin, and phosphorylated by src kinase.

Osteoclast activation is initiated by adhesion to the bone surface, followed by cytoskeletal rearrangement, the formation of the sealing zone, and a polarized ruffled membrane. This study shows that PYK2/CAKbeta/RAFTK, a cytoplasmic kinase related to the focal adhesion kinase, is highly expressed in rat osteoclasts in vivo. Using murine osteoclast-like cells (OCLs) or their mononuclear precursors (pOCs), generated in a coculture of bone marrow and osteoblastic MB1.8 cells, we show: (a) tyrosine phosphorylation of PYK2 upon ligation of beta3 integrins or adhesion of pOCs to serum, vitronectin, osteopontin, or fibronectin but not to laminin or collagen; (b) coimmunoprecipitation of PYK2 and c-Src from OCLs; (c) PYK2 binding to the SH2 domains of Src; (d) marked reduction in tyrosine phosphorylation and kinase activity of PYK2 in OCLs derived from Src (-/-) mice, which do not form actin rings and do not resorb bone; (e) PYK2 phosphorylation by exogeneous c-Src; (f) translocation of PYK2 to the Triton X-100 insoluble cytoskeletal fraction upon adhesion; (g) localization of PYK2 in podosomes and the ring-like structures in OCLs plated on glass and in the sealing zone in OCLs plated on bone; and (h) activation of PYK2, in the presence of MB1.8 cells, parallels the formation of sealing zones and pit resorption in vitro and is reduced by echistatin or calcitonin and cytochalasin D. Taken together, these findings suggest that Src-dependent tyrosine phosphorylation of PYK2 is involved in the adhesion-induced formation of the sealing zone, required for osteoclastic bone resorption.

Animals↗
PubMed2005

Comparison between flutter valve drainage bag and underwater seal device for pleural drainage after lung surgery.

AIM OF THE STUDY: The purpose of the present study was to compare the use of a conventional underwater seal device with suction and a flutter valve drainage bag for pleural drainage after lung surgery. PATIENTS AND METHODS: Altogether 59 patients undergoing elective lung surgery except pneumonectomy between February 2001 and April 2002 were prospectively randomized to receive postoperative pleural drainage by 28F chest tube(s) attached to underwater seal device placed on negative pressure of 15 cm of water or flutter valve drainage bag. Following withdrawal of four patients from the study, 55 patients were evaluated (31 patients in the underwater seal device group and 24 patients in the flutter valve drainage bag group). RESULTS: In the conventional underwater seal device group the mean drainage time was 2.6 (SD +/- 2.0) days and in the flutter valve drainage bag group the mean drainage time was 3.3 days (SD +/- 4.0); difference -0.8, 95% confidence interval (CI) -2.4 to 0.9. The mean length of hospitalization in the surgical ward was 3.6 (SD +/- 2.7) and 4.1 (SD +/- 4.4) days respectively (difference -0.5, 95% CI -2.5 to 1.4). CONCLUSIONS: The results of this study suggest that flutter valve drainage system is a safe and feasible alternative in managing postoperative air leaks and haemorrhage after lung surgery other than pneumonectomy if air leaks are not extremely massive.

Drainage↗
PubMed2002

Optical properties of end-sealed hollow fibers.

We propose sealing techniques for medical hollow fibers to protect the inner surface of fibers from debris or water that scatters from targets. First, hollow fibers are sealed with a film of polymer that is easily formed by use of a dipping technique. The transmission loss of 20-microm-thick sealing film was 0.2 dB for Er:YAG laser light, and the maximum energy that is available for the film was 180 mJ. Second, a sealed glass cap was applied to the output end of hollow fiber. The silica-glass cap with a wall thickness of 400 microm shows a transmission loss of 0.5 dB and was not damaged by radiation of 400-mJ energy pulses.

Journal Article↗
PubMed1998

Ultraconservative and cariostatic sealed restorations: results at year 10.

Changes in restorative techniques and the development of newer restorative materials have allowed for the use of more conservative cavity preparations. This 10-year study evaluated bonded and sealed composite restorations placed directly over frank cavitated lesions extending into dentin vs. sealed conservative amalgam restorations and conventional unsealed amalgam restorations. The results indicate that both types of sealed restorations exhibited superior clinical performance and longevity compared with unsealed amalgam restorations. Also, the bonded and sealed composite restorations placed over the frank cavitated lesions arrested the clinical progress of these lesions for 10 years.

Adolescent↗
PubMedDate not supplied

Effect of diode laser irradiation on the apical sealing of MTA retrofillings.

Apical sealing is essential for the success of paraendodontic surgery, so any procedure that may favor an adequate sealing of the apical remainder should be performed. The purpose of this study was to evaluate the influence of diode laser irradiation on the apical sealing of root-end cavities with MTA retrofillings. Root canals in twenty extracted human teeth were shaped with K-files and filled with gutta-percha. The apexes were cut off and root-end preparations were performed. The roots were divided randomly in 2 groups. Group 1 (ten specimens) was retrofilled with MTA. Group 2 was irradiated with diode laser, with 1 W for 20 seconds, on the apical surface and root end cavity before retrofilling with MTA. The specimens had their external surfaces impermeabilized with cyanoacrylate, except for the apical surface, and were then immersed in 1% rhodamine B dye for 72 h and placed in plaster stone. After that, the specimens were submitted to longitudinal abrasion until half of the root remained. The linear dye leakage was observed in these mid-roots between the root canal wall and retrofilling. The linear dye leakage was measured with Image Lab software, and the results were statistically analyzed with Student's t test. There were no statistically significant differences between the two groups (p > 0.05). The diode laser irradiation did not improve the apical sealing of MTA retrofillings under the conditions of this in vitro study.

Aluminum Compounds↗