The effects of a new ultra-short-acting beta-adrenergic blocker, ONO-1101, on cardiac function during and after cardiopulmonary bypass

The administration of an ultra-short-acting beta-adrenergic antagonist, esmolol, has been introduced as a novel method for beating-heart surgery. In the present study, a new ultra-short-acting beta-blocker, ONO-1101, was administered during cardiopulmonary bypass (CPB) to investigate its effects on cardiac function and hemodynamics. Nine adult mongrel dogs underwent 60 min of CPB during which they were given either ONO-1101 (ONO group; n = 4) or saline (control group; n = 5). In the ONO group, the hearts became flaccid enough for surgery to be performed without cardiac standstill within 10 min after the commencement of ONO-1101 with significant decreases in the heart rate, the preload recruitable stroke work (PRSW), and the slope of the end-systolic left ventricular pressure-volume relationship (Emax). The mean arterial pressure and systemic vascular resistance also decreased, but were maintained above 50 mmHg during CPB without catecholamine. These indices increased to the control group level 20 min after the discontinuation of ONO-1101. The serum concentration of ONO-1101 decreased from the maximum level of 121 +/- 15 microg/ml soon after infusion to 11 +/- 5 microg/ml within 30 min after discontinuation. These data suggest that ONO-1101 may be useful to enable beating-heart surgery to be performed without aortic cross-clamp as an ultra-short-acting beta-adrenergic blocker.

Volatile organic compound emissions from latex paint--Part 1. Chamber experiments and source model development

Latex paints are widely used in residential and commercial indoor environments. The surface areas covered by the paints in these environments are relatively large. Thus, latex paints have the potential for having a major impact on indoor air quality (IAQ). A study was undertaken to develop methods for evaluating the impact of latex paint emission on IAQ. Small chamber experiments using stainless steel and painted and unpainted gypsum board substrates were conducted to determine the emission characteristics of latex paint. The emissions from the stainless steel were relatively short lived (3 to 4 days), whereas the emissions from gypsum board lasted for over 200 days. Because gypsum board is a common substrate for latex paint, all emission models were developed for the gypsum board substrates. The data from the small chamber tests led to the development of two empirical and two mass-transfer-based source emission models. Approximately 100 to 200 days of data were required to estimate the parameters required for the empirical models. Only 8 days of data were required to estimate the parameters for the mass-transfer-based models. The final models use paint formulation and mass transfer correlations to predict the emissions of the major individual volatile organic compounds emitted by latex paint.

Volatile organic compound emissions from latex paint--Part 2. Test house studies and indoor air quality (IAQ) modeling

Emission models developed using small chamber data were combined with an Indoor Air Quality (IAQ) model to analyze the impact of volatile organic compound (VOC) emissions from latex paint on indoor environments. Test house experiments were conducted to verify the IAQ model's predictions. The agreement between model predictions and experimental measurements met the American Society for Testing and Materials criteria for model verification in the room with the source and met most of the requirements in other rooms. The major cause of disagreement between the model predictions and the experimental data in the test house appears to be an inadequate sink model.

Trends in Missouri lung cancer rates

This study presents trend analysis of Missouri lung cancer incidence and mortality, and makes comparisons to U.S. rates. Utilizing 1985-1992 data from the Missouri Cancer Registry, we calculated incidence rates by disease diagnosis year. Missouri Center for Health Information Management and Epidemiology data were used to calculate 1980-1996 mortality rates. Missouri's overall yearly lung cancer incidence rate increased from 60.5 to 62.5 per 100,000 during 1985-1992, while lung cancer mortality increased 25% from 1980-1996. The best method to reduce Missouri's rates of lung cancer is tobacco-use prevention and cessation.

Transgenic knockout mice exclusively expressing human hemoglobin S after transfer of a 240-kb betas-globin yeast artificial chromosome: A mouse model of sickle cell anemia

Sickle cell anemia (SCA) and thalassemia are among the most common genetic diseases worldwide. Current approaches to the development of murine models of SCA involve the elimination of functional murine alpha- and beta-globin genes and substitution with human alpha and betas transgenes. Recently, two groups have produced mice that exclusively express human HbS. The transgenic lines used in these studies were produced by coinjection of human alpha-, gamma-, and beta-globin constructs. Thus, all of the transgenes are integrated at a single chromosomal site. Studies in transgenic mice have demonstrated that the normal gene order and spatial organization of the members of the human beta-globin gene family are required for appropriate developmental and stage-restricted expression of the genes. As the cis-acting sequences that participate in activation and silencing of the gamma- and beta-globin genes are not fully defined, murine models that preserve the normal structure of the locus are likely to have significant advantages for validating future therapies for SCA. To produce a model of SCA that recapitulates not only the phenotype, but also the genotype of patients with SCA, we have generated mice that exclusively express HbS after transfer of a 240-kb betas yeast artificial chromosome. These mice have hemolytic anemia, 10% irreversibly sickled cells in their peripheral blood, reticulocytosis, and other phenotypic features of SCA.

Expression and export of Pseudomonas putida NTU-8 creatinase by Escherichia coli using the chitinase signal sequence of Aeromonas hydrophila

The gene for the creatinase from Pseudomonas putida NTU-8 was sequenced and revealed an open reading frame (ORF) of 1209 base pairs encoding a polypeptide of 403 amino acids with a calculated molecular weight (M(r)) of 45,691. The deduced amino acid sequence is very similar to that of the creatinase of Pseudomonas putida and Flavobacterium sp. An overproduction system for the chitinase signal peptide--creatinase hybrid gene was constructed by using the pQE-51 expression vector in E. coli JM109. The amount of this fusion enzyme was about 50% exported into the periplasmic space of E. coli.

Silicoating in resin-metal bonding: restorative implications for osseointegrated implant-bone unison

Detailed background information leading to the development of a silicoating technique is presented with its advantages and disadvantages and its role in implant dentistry. The rationale is shown for coining a new acronym "osseointegrated Implant-Bone Unison" with an interest in biomechanical considerations for a prosthodontic restorative scenario. Several clinical cases are presented that involve silicoating and composite restorations.

Trends in cancer incidence and mortality in Missouri

BACKGROUND

Cancer is the second leading cause of death in Missouri. Several factors influence public health planning and policy-making decisions, including assessment of the trends in disease and in related risk factors, of overall disease burden on the population, and of the effectiveness of intervention programs. To assess the influence of statewide cancer screening, education, and intervention programs on Missouri's cancer burden, recent trends in cancer incidence and mortality rates among Missourians were analyzed.

METHODS

Age-standardized cancer incidence rates from 1985-1992 and cancer mortality rates from 1985-1994 and 1990-1996 were calculated by race, age group, and sex using data collected by the Missouri Cancer Registry and the Missouri Center for Health Statistics. Rates for each year examined were logged and regressed onto year.

RESULTS

Between 1985 and 1992, the rate of cancer incidence increased by 16.1% (p < .05). From 1985-1994, cancer mortality rate increased by 3.5% (p < .05). Mortality among males, however, decreased between 1990 and 1996. This decrease was particularly pronounced among African-American males. Missouri males endured greater incidence of and mortality from cancer than Missouri females. Elderly males (both African American and white) exhibited the greatest increase in cancer incidence over the periods examined (+27.3% and +31.8% increase respectively, p < .05). Racial differences were nonexistent for cancer incidence rates, but the cancer mortality rate for African Americans was 45% greater than that for whites.

CONCLUSIONS

Although Missouri cancer incidence and mortality rates are higher now compared to 16 years ago, data are presented that indicate a slight decline in mortality rates over the past six years. The recent decline (1990-96) in mortality was present only among men, particularly African-American men. The incidence increase was particularly important for women. Despite the implementation of some programs designed to target minorities and undeserved populations at greater risk, these data indicate that large demographic differences in cancer incidence and mortality still persist. A greater commitment to cancer screening, access to treatment, and cancer prevention programs are necessary to meet Missouri's year 2000 goals for cancer incidence and mortality.

Interaction of Ba2+ with the pores of the cloned inward rectifier K+ channels Kir2.1 expressed in Xenopus oocytes

Interactions of Ba2+ with K+ and molecules contributing to inward rectification were studied in the cloned inward rectifier K+ channels, Kir2.1. Extracellular Ba2+ blocked Kir2.1 channels with first-order kinetics in a Vm-dependent manner. At Vm more negative than -120 mV, the Kd-Vm relationship became less steep and the dissociation rate constants were larger, suggesting Ba2+ dissociation into the extracellular space. Both depolarization and increasing [K+]i accelerated the recovery from extracellular Ba2+ blockade. Intracellular K+ appears to relieve Ba2+ blockade by competitively slowing the Ba2+ entrance rate, instead of increasing its exit rate by knocking off action. Intracellular spermine (100 microM) reduced, whereas 1 mM [Mg2+]i only slightly reduced, the ability of intracellular K+ to repulse Ba2+ from the channel pore. Intracellular Ba2+ also blocked outward IKir2.1 in a voltage-dependent fashion. At Vm >/= +40 mV, where intrinsic inactivation is prominent, intracellular Ba2+ accelerated the inactivation rate of the outward IKir2.1 in a Vm-independent manner, suggesting interaction of Ba2+ with the intrinsic gate of Kir2.1 channels.

A review of breast cancer chemoprevention

Breast cancer remains a major cause of mortality and morbidity, and may be amenable to chemoprevention as estrogen stimulation is believed to be responsible for the promotion of this disease. Tamoxifen is the most widely studied compound for chemoprevention and clinical trials involving over 20,000 women world-wide are currently underway. This drug is well-tolerated with low acute toxicity and high compliance, and has a favorable profile in both decreasing serum cholesterol and increasing bone mineral density in postmenopausal women. However, there are fears of its potential carcinogenicity, especially an increased risk of endometrial cancers, which may jeopardize further recruitment and compliance of women in these chemoprevention studies. Meta-analyses of these studies are expected to be conducted in the year 2000 to address the efficacy of tamoxifen in women with an increased familial predisposition and in those with known germline BRCA mutations.

Characterization of emissions of volatile organic compounds from interior alkyd paint

Alkyd paint continues to be used indoors for application to wood trim, cabinet surfaces, and some kitchen and bathroom walls. Alkyd paint may represent a significant source of volatile organic compounds (VOCs) indoors because of the frequency of use and amount of surface painted. The U.S. Environmental Protection Agency (EPA) is conducting research to characterize VOC emissions from paint and to develop source emission models that can be used for exposure assessment and risk management. The technical approach for this research involves both analysis of the liquid paint to identify and quantify the VOC contents and dynamic small chamber emissions tests to characterize the VOC emissions after application. The predominant constituents of the primer and two alkyd paints selected for testing were straight-chain alkanes (C9-C12); C8-C9 aromatics were minor constituents. Branched chain alkanes were the predominant VOCs in a third paint. A series of tests were performed to evaluate factors that may affect emissions following application of the coatings. The type of substrate (glass, wallboard, or pine board) did not have a substantial impact on the emissions with respect to peak concentrations, the emissions profile, or the amount of VOC mass emitted from the paint. Peak concentrations of total volatile organic compounds (TVOCs) as high as 10,000 mg/m3 were measured during small chamber emissions tests at 0.5 air exchanges per hour (ACH). Over 90% of the VOCs were emitted from the primer and paints during the first 10 hr following application. Emissions were similar from paint applied to bare pine board, a primed board, or a board previously painted with the same paint. The impact of other variable, including film thickness, air velocity at the surface, and air-exchange rate (AER) were consistent with theoretical predictions for gas-phase, mass transfer-controlled emissions. In addition to the alkanes and aromatics, aldehydes were detected in the emissions during paint drying. Hexanal, the predominant aldehyde in the emissions, was not detected in the liquid paint and was apparently an oxidation product formed during drying. This paper summarizes the results of the product analyses and a series of small chamber emissions tests. It also describes the use of a mass balance approach to evaluate the impact of test variables and to assess the quality of the emissions data.

Timed intercourse after intrauterine insemination for treatment of infertility

OBJECTIVE

To compare the pregnancy rates, between intrauterine insemination (IUI) followed by timed intercourse and IUI only for treatment of the infertile couples.

STUDY DESIGN

A prospective study of two different protocols of intrauterine insemination in two hundred and one infertile couples with a normal spermiogram was carried out. Of these, 101 couples were treated with IUI alone and 100 couples had both IUI and timed intercourse within a 12-18 h period. The pregnancy rates were compared between groups.

RESULTS

The characteristics of the two groups were similar in terms of the mean age, as well as the duration and causes of infertility. The cycle characteristics following follicular stimulation were also similar between two groups. The pregnancy rate per cycle increased with increasing numbers of total motile sperm per insemination in the IUI alone group (P=0.045). Timed intercourse increased pregnancy rate in patients with lower motile sperm number (<40x10(6)) (27.7% versus 10.5%, P=0.023), but not in patients with higher sperm number (> or =40x10(6)) (25.7% versus 22.7%, P=0.671).

CONCLUSIONS

In IUI with low number of motile sperm inseminated, timed intercourse significantly increases the pregnancy rates over IUI alone in infertile couples with a normal sperminogram. This alternative treatment appears to be a practical, simple, and inexpensive addition that improves the pregnancy rate in patients receiving ovulation induction and intrauterine insemination program.

Hepatic cavernous hemangioma: sonographic patterns and speed of contrast enhancement on multiphase dynamic MR imaging

OBJECTIVE

Our purpose was to investigate a correlation between the speed of contrast enhancement in patients with hepatic cavernous hemangioma revealed by dynamic MR imaging and the internal echo pattern revealed by sonography.

MATERIALS AND METHODS

Forty-five patients underwent multiphase IV contrast-enhanced dynamic MR imaging that revealed 71 hepatic cavernous hemangiomas less than 4 cm in diameter; the MR findings were compared with the sonographic findings in these patients. On MR imaging, the hemangiomas were classified as rapid-, intermediate-, and slow-enhancing. We classified sonographic features as hypoechoic, iso- or mixed-echoic, and hyperechoic according to the relative echogenicity seen between lesions and the surrounding hepatic parenchyma. Sonographic patterns and MR imaging findings of individual lesions were then compared.

RESULTS

Rapid-enhancing hemangiomas revealed on dynamic MR imaging tended to be hypoechoic on sonography (18/24, 75%; p = .0143), and lesions that were slow-enhancing on MR imaging tended to be hyperechoic (26/29, 90%; p < .0001). Hypoechoic lesions on sonography tended to be rapid-enhancing on dynamic MR imaging (18/18, 100%). Likewise, hyperechoic lesions on sonography tended to be slow-enhancing on MR imaging (26/33, 79%; p = .0009).

CONCLUSION

In most patients with hepatic cavernous hemangiomas, we found that the speed of contrast enhancement on multiphase dynamic MR imaging enabled us to predict the echo pattern in sonography and vice versa.

Evaluation of sink effects on VOCs from a latex paint

The sink strength of two common indoor materials, a carpet and a gypsum board, was evaluated by environmental chamber tests with four volatile organic compounds (VOCs): propylene glycol, ethylene glycol, 2-(2-butoxyethoxy)ethanol (BEE), and Texanol. These oxygenated compounds represent the major VOCs emitted from a latex paint. Each chamber test included two phases. Phase 1 was the dosing/sorption period during which sink materials (pieces of carpet and gypsum board samples) were exposed to the four VOCs. The sink strength of each material tested was characterized by the amount of the VOCs adsorbed or absorbed. Phase 2 was the purging/desorption period during which the chambers with the dosed sink materials were flushed with purified air. The reemission rates of the adsorbed VOCs from the sinks were reflected by the amount of the VOCs being flushed. Phase 1 results indicated that the sink strength for the four target compounds is more than 1 order of magnitude higher than that for other VOCs previously tested by the U.S. Environmental Protection Agency (EPA). The high sink strength reflected the unusually high sorption capacity of common indoor materials for the four VOCs. Phase 2 results showed that reemission was an extremely slow process. If all the VOCs adsorbed were reemittable, it would take more than a year to completely flush out the VOCs from the sink materials tested. The long reemission process can result in chronic and low-level exposure to the VOCs after painting interior walls and surfaces.

Successful experimental multiorgan transplant from non-heart-beating donors using percutaneous cardiopulmonary support

Organ procurement from non-heart-beating donors (NHBDs) may expand donor pools. In this study, the method of reanimation of heart, lung, and kidney in NHBDs by percutaneous cardiopulmonary support (PCPS) was evaluated. Thirteen beagles were asphyxiated after being given prostacyclin analogue, verapamil, propranolol, and nafmostat mesilate intravenously. Thirty minutes after cardiac arrest, the body was reperfused by PCPS for 1 hr. PCPS priming fluid contained the four drugs above and KCl. Eight hearts immersed in University of Wisconsin (Madison, WI) solution for 24 hr were transplanted orthotopically using leukocyte depleted blood cardioplegia, five left lungs immersed in modified Collins solution were transplanted orthotopically, and five kidneys immersed in University of Wisconsin solution were transplanted heterotopically. All donor hearts arrested without ventricular fibrillation. All transplanted hearts beat spontaneously, and all animals were weaned from cardiopulmonary bypass without inotropic support. The oxygen and carbon dioxide pressure of pulmonary vein blood in the donor lung were no different from those in the recipient lung. All transplanted kidneys made urine soon after reperfusion. These data suggested that hearts, lungs, and kidneys from NHBDs pretreated with four drugs and reanimated with PCPS can be transplanted successfully and that this method may expand the donor pool.

Nitric oxide gas infusion to the oxygenator enhances the biocompatibility of heparin coated extracorporeal bypass circuits

Heparin coated bypass circuits have been reported to improve the biocompatibility of extracorporeal circulation, although it is still insufficient and improvable. Nitric oxide (NO) is known to inhibit platelet activation and inflammatory reactions. In this study, the authors evaluated exogenous NO infusion in enhancing the effect of a heparin coated bypass circuit on the biocompatibility of an extracorporeal circuit, especially in view of the attenuation of the inflammatory response. A miniature closed bypass circuit, including an oxygenator (BioActive surface; Carmeda, Stockholm, Sweden) was primed with fresh human heparinized blood and perfused with a centrifugal pump. Either pure N2 gas (control group: n = 7) or NO gas (NO group [100 ppm in N2]: n = 7) was infused to the oxygenator. NO metabolites (nitrite and nitrate), platelet count, thrombin-antithrombin III complex (TAT), alpha2-plasmin-plasminogen inhibitor complex (PIC), beta-thromboglobulin (beta-TG), platelet factor 4 (PF4), serotonin, complement 3 activation products (C3a), granulocyte elastase, and bradykinin were measured at 0, 30, 60, 120, and 180 min after starting perfusion. At every sampling point, platelet counts were significantly higher, and TAT, beta-TG, and bradykinin were lower in the NO group than in the control group. PF4, C3a, and granulocyte elastase were significantly lower in the NO group at 60, 120, and 180 min. These results suggest that NO gas infusion to the oxygenator enhances the biocompatibility of heparin coated extracorporeal circuits.

Effect of postprepared sperm parameters and insemination specimen volume on the outcome of intrauterine insemination

BACKGROUND

The purpose of the present study was to identify the postprepared sperm parameters affecting the outcome of intrauterine insemination and to find out whether the volume of insemination specimen was a determinant factor in the rate of successful conception.

MATERIALS AND METHODS

A retrospective study including 306 couples was designed. The patients were inseminated with either 1.0 or 0.5 ml of prepared specimens. The pregnancy rates were compared using the chi-square test. Logistic regression was chosen for multivariant analysis of the parameters.

RESULTS

The only parameter significantly affecting the success rate was the postprepared sperm motility (p = 0.033). The pregnancy rate was 27.91% in cases with > or = 95% sperm motility. Only two patients with less than 75% sperm motility conceived. The pregnancy rates in cases with 0.5 ml and 1.0 ml inseminations were 12.12% and 16.13%, respectively. This difference was statistically insignificant (p = 0.427).

CONCLUSION

The postprepared sperm motility was the only parameter predicting the successful rate of intrauterine insemination. Seventy-five percent sperm motility can be used as a cut-off value for selecting patients. The volume of insemination specimen did not influence the outcome. Insemination with 1 ml of fluid was just as effective as insemination with 0.5 ml.

Adjuvant activity of incomplete Freund's adjuvant

The water-in-oil emulsion adjuvants developed by Jules Freund and coworkers have been, and continue to be, used in research and veterinary vaccines. Incomplete Freund's Adjuvant (IFA) has also been widely tested in humans where it was shown to augment antibody responses greater than other adjuvants, such as alum, and to be well tolerated. Toxicity associated with the use of IFA has been controlled by the use of high grade oils and purified surfactants and clinical testing is ongoing to day. One potential limitation of IFA is that it does not augment the types of cellular immune responses that thought to be critical to the control of many viral infections and tumors. However, IFA can be mixed with or used in conjunction with other adjuvant-active compounds, such as saponins and cytokines. These mixed formulations or vaccine protocols have proved successful in animal testing and may soon be tested in clinical trials. Thus, the toxicity and potential limited adjuvant activity of IFA can be controlled or corrected making IFA a useful product in the vaccine industry.

Guillain-Barré syndrome: MR imaging findings of the spine in eight patients

PURPOSE

To evaluate magnetic resonance (MR) imaging findings of the spine in patients with Guillain-Barré syndrome.

MATERIALS AND METHODS

MR imaging findings in eight patients (three male, five female; age range, 2-47 years) with Guillain-Barré syndrome were retrospectively reviewed. Guillain-Barré syndrome was diagnosed mainly on the basis of symptoms and also on the basis of supportive ancillary data, such as the results cerebrospinal fluid analysis and electrophysiologic evaluation. In addition, follow-up MR imaging was performed in three patients, who had slight clinical improvement.

RESULTS

All patients had thickening of the intrathecal spinal nerve roots and cauda equina, with varying degrees of enhancement on gadolinium-enhanced axial T1-weighted images. Two enhancement patterns were noted. One was enhancement of both the anterior and posterior spinal nerve roots (n = 2); the other was enhancement of the anterior spinal nerve roots only (n = 6). Follow-up MR imaging in the three patients with slight improvement of symptoms revealed that the thickening and the degree of enhancement of the spinal nerve roots were diminished.

CONCLUSION

Although the enhancement of the intrathecal spinal nerve roots is not specific to Guillain-Barré syndrome and can be seen in neoplasia and other inflammatory processes, the enhancement of only the anterior spinal nerve roots is strongly suggestive of Guillain-Barré syndrome.

Hybrid total knee arthroplasty: a 3- to 6-year outcome analysis

We retrospectively analyzed the outcomes of hybrid total knee arthroplasty (TKA) with Miller Galante I (MG I) prostheses in 113 consecutive patients (140 knees). The mean follow-up period was 4.8 years (range 3.2-6.6). There were 135 cases of osteoarthritis and five of rheumatoid arthritis. The average age of patients at the time of surgery was 62.6 years. The Hospital for Special Surgery knee score along with radiographs were used to evaluate preoperative and postoperative knee status, and the Cybex isokinetic test was used to assess muscle strength at the final follow-up. The average knee score improved from 64 points preoperatively to 90 points postoperatively (p < 0.05). The mean motion are of the knee improved from 108 degrees preoperatively to 116 degrees at the final evaluation. A total of 122 knees were pain free on walking and 130 knees were completely pain free at rest. A total of 134 knees achieved good to excellent clinical results. The radiographic results showed that the mechanical axis of the lower extremity was realigned from a mean of 12 degrees varus preoperatively to a mean of 1 degree varus postoperatively. No obvious radiolucent zones were found on the lateral view of the femoral components in 60.7% of the knees, or on the anteroposterior or lateral views around the tibial components in 49.3% and 82.9% of knees, respectively. The Cybex isokinetic test at the final follow-up examination revealed that the hamstring/quadriceps peak torque ratio was 0.8 at a speed of 60 degrees per second and 0.96 at 180 degrees per second, indicating that quadriceps muscle strength did not recover to within the range of healthy subjects. There were 23 (16.4%) complications, including polyethylene wear of patellar components (14), patellofemoral maltracking (4), septic loosening (2), aseptic loosening (2), and superficial infection (1). Revision surgery improved the functional outcomes in all of these knees. Based on our experience, we do not recommend the use of the MG I prosthesis in total knee arthroplasty (TKA) because of the high rate of patellar complications. Strengthening of the quadriceps must be emphasized in postoperative rehabilitation. Hybrid fixation might be a useful alternative fixation mode in TKA procedures.

Tensile bond strengths of dual-cured cements between a glass-ceramic and enamel

STATEMENT OF THE PROBLEM

Dual-cured cements have been used with castable ceramic restorations, but the tensile bond strengths of these materials have not been thoroughly researched.

PURPOSE OF THE STUDY

This study compared the tensile bond strengths between Dicor castable ceramics and enamel of four dual-cure cements: Twinlook, Optec Dual-Cure Luting Cement, Clearfil CR Inlay, and Dual Cement.

MATERIAL AND METHODS

Truncated cones made of Dicor castable ceramics were cemented to enamel of freshly extracted anterior teeth with these four cements. Before testing, all specimens were immersed in water at 37 degrees C for 24 hours, and thermocycled 1000 times in 5 degrees C and 55 degrees C water, with a dwell time of 30 seconds each. Tensile force was used to separate each specimen with the Instron universal testing machine.

RESULTS

Clearfil CR Inlay cement exhibited the highest mean tensile bond strength (18.4 MPa), followed by Dual (18.3 MPa), Twinlook (15.2 MPa), and Optec Dual-Cure luting (14.9 MPa) cements. One-way analysis of variance did not reveal any significant differences (p = 0.05) among groups. A majority of the fracture was adhesive at the ceramic and cement interface.

CONCLUSION

All four dual-cured cements formed strong bonds between enamel and Dicor cement, ranging from 14.90 MPa to 18.35 MPa, and there was no statistically significant difference.