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At least 1,009 records · Page 56Linked to original sources
PubMed1982

Analysis of the posterior palatal seal and the palatal form as related to the retention of complete dentures.

Dislodging forces were applied at three different locations--anterior, posterior, middle--on acrylic resin bases of uniform thickness. The influence of different posterior palatal seals and the form of the palate were evaluated. A Pearson statistical correlation analysis was performed to correlate these factors. The findings were as follows: 1. The anterior attachment needed for greatest amount of force to dislodge the base; the posterior attachment needed the least. 2. The middle attachment showed more variability of the forces needed to dislodge the bases. It was influenced by the form of the palate, the type of posterior palatal seal, and the weight of the bases. 3. The middle location is the most reliable region for testing the retention of complete dentures. 4. The form of the palate has direct influence on the retention of complete dentures and will aid in the selection of the type of posterior palatal seal needed.

Denture Bases↗
PubMed1981

Evaluation of the apical seal obtained with endodontic implant stabilizers and different cementing materials.

Preliminary research was conducted to evaluate in vitro the apical seal obtained with endodontic implant stabilizers in conjunction with four different cement sealers. Standard laterally condensed gutta-percha cones and sealer were used as a control. Apical leakage was measured with the use of methylene blue dye solution. Gross leakage patterns resulted from endodontic implants cemented with both zinc phosphate and polycarboxylate. However, leakage appeared notably reduced when the implants were cemented with cyanoacrylate and Kerr Tubli-Seal. Statistical analysis showed that the lateral condensation of gutta-percha cones and sealer yielded the largest proportion of favorable results. Even so, none of the techniques employed was totally effective for obtaining a hermetic sealing of the root canal.

Chemical Phenomena↗
PubMed1990

Sealing ability of intermediate restorations and cavity design used in endodontics.

Temporary filling materials are used in endodontics to prevent contamination of the root canal system during intertreatment visits. Recently, a new composition resin (TERM) has been introduced as an interim restoration in endodontics. The purpose of this investigation was to evaluate the efficacy of this resin as an interim restoration and possible effect of access cavity design with respect to its sealing ability compared with other temporary restorative materials. Sixty human teeth were divided into two categories, and two types of access cavities were prepared, namely tapered access with walls divergent toward the occlusal surface and straight access with parallel walls. The prepared teeth from each category were divided into three subgroups of ten each to receive Cavit (group I), IRM (group II), or TERM (group III). After the fillings were placed, the teeth were transferred into a humidor where they stayed for 24 hours. The teeth were then thermocycled. Each group was thermocycled for 2 hours at 1 minute intervals at 60 degrees C and 4 degrees C. Then the teeth were sealed with a compound and coated with two layers of clear varnish, with the exception of cavity margins. Each occlusal surface was immersed in a vial containing silver nitrate. The teeth were sectioned longitudinally, and the degree of dye penetration was evaluated under a dissection microscope according to set criteria. Our findings demonstrated that design of cavity preparation was not a functional parameter in leakage pattern. Results indicated that Cavit had the best sealing ability whereas IRM showed the maximum dye penetration.

Calcium Sulfate↗
PubMed1991

Acute pulpal-alveolar cellulitis syndrome. V. Apical closure of immature teeth by infection control: the importance of an endodontic seal with therapeutic factors. Part 2.

During orthodontic treatment to promote eruption of maxillary and mandibular second bicuspids, a young male patient had a severe endodontic cellulitis of a mandibular bicuspid. Apexogenesis and resolution of the periapical lesion was achieved by infection control with nonspecific intracanal medication without calcium hydroxide, as stated by Das. A mild periodontal cellulitis occurred shortly thereafter and rapidly resolved. A second endodontic cellulitis, after apexogenesis without an endodontic seal, occurred shortly after completion of orthodontic treatment. This also quickly resolved, and the canal was effectively sealed. This case indicates the importance of an effective endodontic seal shortly after apexogenesis is induced by infection control. This report and others on the subject indicate that apexogenesis of nonvital permanent immature teeth by infection control is a predictable endodontic treatment procedure.

Acute Disease↗
PubMed1989

Long-term sealing properties of amalgam restorations: an in vitro study.

Conventional and high-copper Class V amalgam restorations showed leakage after seven months' storage in artificial saliva and thermal-stressing. The rate of marginal microleakage was not significantly affected by the application of a Copal varnish after this period. At the 14-month storage and thermal-stressing period, all varnished and unvarnished high-copper restorations and the varnished conventional amalgam restorations showed significantly improved sealing properties in the occlusal wall compared with the seven-month period. The unvarnished conventional amalgam restorations appeared to have reached their peak sealing level by seven months under the conditions of this experiment. No significant improvement in the sealing properties of either the conventional or high-copper amalgam restorations was achieved after the 14-month period by the application of Copal varnish.

Copper↗
PubMed1983

In vitro properties of mixtures of fibrin seal and antibiotics.

The incorporation of gentamycin, neomycin and Polymyxin E into fibrin seal results in prolonged clotting time after mixture with 4 NIH-units of thrombin per ml in vitro. The aminoglycoside antibiotics gentamycin and neomycin also diminished fibrin-alpha-chain crosslinkage and, as a consequence, clot rigidity, as demonstrated with clots containing gentamycin. Clotting time and the rate of alpha-chain crosslinking can be adjusted to normal values by the use of higher thrombin concentrations and incorporation of additional factor XIII into the sealing system. Drug release from the clots was similar for all three antibiotics tested and mainly dependent on the concentration gradient between the clot and its environment. Under the conditions of the present study, about 85% of the antibiotic content of fibrin seal clots were released within 72 h.

Anti-Bacterial Agents↗
PubMed1994

A new fibrin seal: functional evaluation of sensory regeneration following primary repair of peripheral nerves.

A new fibrin seal has recently been evaluated in terms of axonal regeneration; however morphological examination of the fibre composition of regenerated nerves may not necessarily provide functionally relevant information. This study therefore aims to evaluate the functional regenerated sensation, following peripheral nerve transection treated with fibrin seal (Tisseel-Duo, Immuno; Austria). The sural nerve-innervated skin of the rat hindfoot served as the target organ. Previously published results from animals following transection and suture served as controls. Ten 3-month-old female Sprague-Dawley rats were used. The sciatic nerve was divided and rejoined with fibrin seal. The rats were allowed unrestricted movement directly after surgery and allowed to survive for 3 months. Our observations show that the functional results of regenerated polymodal nociceptors and low-threshold mechanoreceptors show no statistical difference when compared with microsuture. This strengthens the early positive morphological impression of this new product. Further prospective studies in man are anticipated.

Animals↗
PubMed1986

Calcium current in mouse eggs recorded with the tight-seal, whole-cell voltage-clamp technique.

The tight-seal, whole-cell recording technique has been used to voltage-clamp unfertilized eggs of the mouse. Good seal formation was obtained in a solution containing 20 mM Ca2+ and the transient inward Ca2+ current recorded. This technique offers several advantages over the conventional, two-microelectrodes voltage-clamp: improved signal to noise ratio; larger membrane-pipette seal resistance; possibility of very stable, long duration, recordings and possibility of controlling the intracellular medium. The main disadvantage of the technique, namely the rundown of channels due to loss of intracellular components, was not encountered in this preparation.

Animals↗
PubMed1996

Airway sealing pressures of the laryngeal mask airway in pediatric patients.

STUDY OBJECTIVES: To determine if the laryngeal mask airway (LMA) seal is maintained during surgery, to evaluate the safety of an LMA leak test, and to determine the time course of the increase in LMA cuff pressure in vivo in the presence of nitrous oxide (N2O). STUDY DESIGN: Descriptive clinical study. SETTING: University teaching hospital. PATIENTS: 78 ASA Physical Status I and II pediatric patients, aged 3 months to 17 years, undergoing general anesthesia with an LMA; 14 patients were studied on two occasions approximately 2 months apart. INTERVENTIONS: The airway pressure at which the LMA seal was broken (leak pressure) was determined immediately following insertion of the LMA and at the end of surgery. In 17 patients, the LMA cuff pressure was continuously measured during surgery, during which 67% N2O was administered. The mean duration of surgery was 29.5 minutes. MEASUREMENTS AND MAIN RESULTS: The LMA leak pressure was determined by closing the circuit popoff valve and recording the pressure at which gas was first heard to escape around the LMA at the mouth. The LMA cuff pressure was determined by connecting the check valve of the LMA pilot balloon to a sphygmomanometer. The elastance of the LMA was determined from the slopes of the regression lines of pressure versus volume for the various sized LMAs in vitro (Sizes 1-4) and in vivo (sizes 2 and 2 1/2). The initial LMA leak pressure was 25.9 cm H2O, and it increased to 31.2 cm H2O during surgery (p < 0.001). 146 leak tests were performed without causing gastric dilatation or LMA dislodgement. The mean LMA cuff pressure increased during surgery from 106.2 mmHg to 132.8 mmHg (p < 0.001), a pressure increase that corresponds to a volume increase of 1.4 ml. CONCLUSIONS: The LMA leak test can be safely performed. The airway seal provided by the LMA is well maintained during surgery. The increase in LMA cuff pressure during surgery in the presence of N2O is small and probably is not a cause for clinical concern. If positive pressure is to applied in the presence of an LMA, one should limit this pressure to below the LMA leak pressure so as to lower the risk of inflating the stomach with gas that may than leak around the LMA.

Adolescent↗
PubMed1996

Prophylaxis against Staphylococcus epidermidis vascular graft infection with rifampicin-soaked, gelatin-sealed Dacron.

An animal model was used to assess the efficacy of rifampicin-impregnated, gelatin-sealed Dacron in the prevention of vascular graft infections caused by Staphylococcus epidermidis. Under a general anaesthetic an interposition graft was placed into sheep carotid artery. On completion of the operation 1 ml of normal saline containing 10(8) colony forming units (cfu) of a slime-producing S. epidermidis was inoculated directly onto the graft. After 3 weeks the graft was harvested. Swabs were taken of perigraft tissues, and of external and internal aspects of the graft. A 3-5-mm segment of the graft was incubated in broth medium and a second segment was ground for 5 min and incubated in broth medium. The presence of abscess formation and anastomotic disruption was assessed. Ten sheep received a gelatin-sealed Dacron graft (control), while nine received the same graft impregnated with rifampicin at a concentration of 1.2 mg/ml (treated). Eight of 10 control grafts were infected, with 30 of 50 possible cultures positive, compared with four of nine treatment grafts infected (P = 0.13) and 13 of 45 cultures positive (P = 0.004). The control group had four abscesses and two anastomotic disruptions; the treatment group had no abscesses (P = 0.05) or anastomotic disruptions (P = 0.26). Other organisms were isolated from nine of the 12 infected grafts, most commonly Staphylococcus aureus. There was no development of resistance to rifampicin. Rifampicin-impregnated, gelatin-sealed Dacron is successful at reducing the incidence of S. epidermidis vascular graft infection.

Administration, Topical↗
PubMed1992

The relationship among bronchial blocker cuff inflation volume, proximal airway pressure, and seal of the bronchial blocker cuff.

The resting volume and diameter of the bronchial blocker cuff (defined as inflation of the cuff to just its natural shape) of the Univent (Fuji Systems Corp, Tokyo, Japan) tube are 2 mL and 5 mm. However, much larger inflation volumes may be required to seal an adult mainstem bronchus and the surface area of contact between the resultant spherical or ellipsoid-shaped cuff and the wall of the mainstem bronchus may be small and susceptible to leak with the application of high proximal airway pressures. This experiment determined the relationship among airway diameter, proximal airway pressure, inflation volume of the bronchial blocker cuff, and leakage of air around the bronchial blocker cuff in an in vitro model. The experimental model consisted of silicon tubing of 12.8-, 16.0-, and 19.2-mm ID as the mainstem bronchus. The main tracheal cuff sealed the Univent tube into the proximal end of the mainstem bronchus and the bronchial blocker cuff was inflated with various volumes near the distal end of the mainstem bronchus. The space between the tracheal cuff and the bronchial blocker cuff was then progressively pressurized in either a static or pulsed manner. The very distal end of the bronchus was functionally submerged under a beaker of water so that a bronchial blocker cuff leak would be indicated by bubbling. It was found that the Univent bronchial blocker cuff sealed the 12.8- and 16.0-mm ID mainstem bronchi against airway pressures as great as 100 cmH2O, with inflation volumes that were within the manufacturer's recommendation of 6 to 7 mL.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

Off-pump epicardial tissue sealing--a novel method for atrioventricular disruption complicating mitral valve procedures.

BACKGROUND: Atrioventricular disruption (AVD) is a rare (1%-2%) but fatal complication after mitral valve procedures; the intraoperative mortality is more than 50% despite the current standard procedure of surgical closure of the defect. We compared the outcome of 9 patients with intraoperative AV disruption, 4 being surgically treated on-pump and 5 receiving epicardial tissue sealing off-pump. METHODS: Between March 1998 and May 2002 a total of 9 patients presented with AV disruption intraoperative. The first 4 patients were treated with surgical repair on-pump by reconstruction of the defects with patch or buttressed suture. The second series of 5 patients were treated with a biodegradable collagen system with fibrinogen-based coating off-pump. Three to six layers were placed over the bleeding site with manual pressure for 30-60 minutes on the beating heart until bleeding was stopped. Cell saved blood was retransfused. RESULTS: In the on-pump surgical repair group 3 patients (75%) died within the first day after repair either because of persistent bleeding or cardiac tamponade. One patient survived at 30 days and 1 year. In the off-pump tissue sealing group 30 days and 1 year survival was 100%. Postoperative echocardiography showed normal left ventricular (LV) function with no regional wall motion abnormalities. CONCLUSIONS: Our data show that epicardial tissue sealing off-pump results in successful termination of bleeding from AVD and considerably improves survival when compared with the standard procedure. Because of this tremendous improvement in patient survival we now consider this technique as standard therapy for AV disruption in our center.

Aged↗
PubMed2006

Use of an electrothermal bipolar tissue sealing system in lung surgery.

OBJECTIVE: We evaluated the validity of an electrothermal bipolar tissue sealing system (LigaSure, Valleylab Inc., USA) in lung surgery. METHODS: Our study was divided into two phases. EXPERIMENTAL: We performed sutures of pulmonary vessels and bronchi and lung wedge resections by LigaSure in 28 lungs of adult pigs; subsequently, we quantitated the sealing capacity of the system detecting the burst pressure for each anatomical structure. Clinical: LigaSure was used in 36 patients undergoing lung surgery. We performed 23 thoracotomic procedures in 16 patients (19 wedge resections, 2 segmentectomies, and 2 fissure separations), and 20 thoracoscopic procedures (13 wedge resections, 5 bullectomies, and 2 adherence dissections). RESULTS EXPERIMENTAL: Bronchi and vessels were divided into seven groups (diameter: 1-7 mm); 10 burst pressure measurements for each group were performed. A total of 84 wedge resections were performed; lung specimens were divided into seven groups (weight: 0.2-1.4 g). The percentage of bronchial sutures resistant to the pneumatic critical pressure (60 mmHg) was 100% in the 1-mm and 2-mm groups. No bronchi with 6-mm or 7-mm diameter reached the critical pressure. All pulmonary vessel sutures were resistant to the critical hydrostatic pressure (150 mmHg). The average burst pressure of wedge resection margins was higher than the critical pressure, and the percentage of suture margins resistant to the critical pressure decreased from 95% (0.2-g group) to 68% (1.4-g group). Histology confirmed the sealing of vessels, with a mean depth of thermal injury limited to 1.1mm. Clinical: In all patients, hemostasis obtained by LigaSure was effective, with minimal perioperative bleeding. The mean operating time was 77.2 min (range: 60-97) for thoracotomies and 60.3 min (range: 46-80) for thoracoscopies. The mean drainage duration was 3.1 days (range: 1-8). Two patients had prolonged air leaks (>7 days). The mean postoperative stay was 7.3 days (range: 5-13) for thoracotomies and 4.6 days (range: 1-6) for thoracoscopies. CONCLUSIONS: Use of LigaSure in lung surgery appears feasible and easy. It provides satisfactory hemostasis and air-leak prevention; results are comparable to those of stapling devices, but this system seems to have a better benefit/cost ratio. Larger series are needed to confirm these data.

Adult↗
PubMed2006

Organochlorines in harbor seal (Phoca vitulina) tissues from the northern Gulf of Alaska.

Polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its metabolites, heptachlor and hexachlorocyclohexanes (HCHs) were analyzed in the harbor seal (Phoca vitulina) tissues collected from the Gulf of Alaska during 2000-2001. summation SigmaPCBs (16-728 ng/gl w) and summation SigmaDDTs (14-368 ng/gl w) were the predominant pollutants followed by summation operatorHCHs (0.56-93 ng/gl w) and heptachlor (<or=0.068-6.0 ng/gl w). Concentrations of the above organochlorines (OCs) in the liver, kidney and blubber tissues correlated with ages, sex, body weight and blubber thickness of the harbor seals. The OC concentrations were similar between the samples collected from two different regions--Prince William Sound, and Kodiak Island and Southern Alaska Peninsula. Mean levels of OCs in nursing female adults were much lower than those in male adults, which indicate that lactation transfer OCs from mother seals to newborns.

Adipose Tissue↗
PubMed2006

Can mucosal sealing reduce tonsillectomy pain?

OBJECTIVE/HYPOTHESIS: The hypothesis tests whether sealing the tonsillectomy field with posterior pillar mucosa can prevent unwanted outcomes in pediatric tonsillectomy. STUDY DESIGN: A prospective, randomized, single blinded study was conducted on a sample of 39 children between 3 and 15 years of age. After dissection and snare tonsillectomy, the tonsillar fossa was covered on one side using the palatopharyngus mucosa and the other side is used as control. Pain scores, healing, edema and infection at the operation site were investigated. METHODS: The tonsillectomy sites were randomly assigned into one of two groups. First group contained the ones with mucosal flap sealed over the operation site and the second group was kept as control with the operation site left uncovered. All of the patients received mild analgesics. The pain assessment is done on Days 1, 3, 5, 7 and 10 postoperatively, by using Wong-Baker faces visual analog scale. On the 10th postoperative day, the operation field of each side is scored separately for edema, healing and infection. Statistical investigation was performed through a software program. RESULTS: On first postoperative day, pain level difference was not statistically significant between the two groups (p>0.01). But from 3rd to 10th postoperative day, the pain level was found out to be lower in the mucosa sealed site (p<0.01). On the 10th postoperative day, while the edema was significantly more (p<0.01), healing was better (p<0.01) at the sutured site. Postoperative infection at operation site was not different between the groups (p>0.01). CONCLUSION: Covering tonsillectomy field with mucosal palatopharyngeal arch flap significantly reduces pain after third postoperative day. The flap side had better healing when compared to denuded site. But the sutures in the mucosal flap may cause more tissue edema. Sutures have no significant effect on postoperative infection. Thus, mucosal flap may be used as an adjuvant surgical technique to decrease tonsillectomy pain of children in addition to the analgesic medication.

Adolescent↗
PubMed2004

Does sealing endotracheal tube cuff pressure diminish the frequency of postoperative laryngotracheal complaints after nitrous oxide anesthesia?

STUDY OBJECTIVES: To study endotracheal tube (ETT) cuff pressures during nitrous oxide (N2O) anesthesia when the cuffs are inflated with air to achieve sealing pressure, and to evaluate the frequency of postoperative laryngotracheal complaints. DESIGN: Prospective, randomized, blind study. SETTING: Metropolitan teaching hospital. PATIENTS: 50 ASA physical status I and II patients scheduled for elective abdominal surgery. INTERVENTIONS: Patients received standard general anesthesia with 66% N2O in oxygen. In 25 patients, the ETT cuff was inflated with air to achieve a sealing pressure (Pseal group). In 25 patients, the ETT cuff was inflated with air to achieve a pressure of 25 cm H2O (P25 group). MEASUREMENTS AND MAIN RESULTS: ETT intracuff pressures were recorded before (control) and at 30, 60, 90, 120, and 150 minutes during N2O administration. We investigated the frequency and intensity of sore throat, hoarseness, and dysphagia in patients in the Post-Anesthesia Care Unit (PACU) and 24 hours following tracheal extubation. The cuff pressures in the Pseal group were significantly lower than in the P25 group at all time points studied (p < 0.001), with a significant increase with time in both groups (p < 0.001). The cuff pressures exceeded the critical pressure of 30 cm H2O only after 90 minutes in the Pseal group and already by 30 minutes in the P25 group. The frequency and intensity of sore throat, hoarseness, and dysphagia were similar in both groups in the PACU and 24 hours after tracheal extubation (p > 0.05). CONCLUSIONS: Minimum ETT sealing cuff pressure during N2O anesthesia did not prevent, but instead attenuated, the increase in cuff pressure and did not decrease postoperative laryngotracheal complaints.

Adult↗
PubMed2006

Probabilistic biokinetic modelling of radiocaesium uptake in Arctic seal species: verification of modelled data with empirical observations.

The necessity to provide information about radionuclide concentrations in Arctic marine species has been heightened in recent years due to a number of accidents in Arctic regions involving nuclear vessels and the presence of a large number of potential radioactive contamination sources. The provision for such information is largely dependent on the use of radionuclide uptake and transfer models. The uptake of radionuclides in Arctic seal species in this study has been modelled using a probabilistic biokinetic approach. In this paper, model results are compared with empirical data from relevant samples taken within the Arctic region. Results indicate that the model performs well when estimating concentrations of (137)Cs in two seal species for both median values and reproduction of the distribution of data values, but not as well for a third seal species. Likely factors affecting the results are the probability density functions used for the input parameters.

Animals↗
PubMed2006

ELISE NMR: experimental liquid sealing of NMR samples.

We present a simple, generally applicable approach to prevent sample evaporation when working at elevated temperatures in high resolution NMR. It consists of experimentally sealing the NMR sample by a second liquid (Experimental Liquid Sealing, ELISE). For aqueous samples, we identified the mineral oil commonly used in PCR application as the best candidate, because it contains only a very limited amount of water-soluble contaminants, is stable over time and heat resistant. The procedure does not interfere with shim settings, and is compatible with a wide variety of samples, including oligosaccharides and proteins. For chloroform samples, a simple drop of water allows to efficiently seal the sample, avoiding solvent evaporation even over lengthy time periods.

Bacterial Proteins↗