The effect of preparation design on the fracture resistance and adaptation of the CEREC ceramic endocrowns

OBJECTIVE

The purpose of this experimental in vitro study was to assess the effect of having one or two intact axial walls on the improvement of the fracture resistance, and marginal and internal adaptation of computer-aided design/computer-aided manufacturer fabricated ceramic endocrowns.

MATERIALS AND METHODS

Thirty-six endodontically treated mandibular molars were divided into three groups (n = 12). Group A, represented teeth that all of their axial walls were reduced till they all had 3 mm height. In group B, the buccal wall had 5 mm height and the others were reduced to 3 mm. Specimens of the group C had 5-mm-height buccal and one 5 mm-height proximal wall, with all other walls of 3 mm height. All teeth were scanned using intraoral scanner, and endocrowns were milled from zirconia lithium silicate ceramics blocks. The marginal and internal discrepancy of restorations were evaluated with the replica technique. Fracture resistance was also measured after cementation and modes of failure were observed. One-way analysis of variance and Tukey HSD multiple comparisons were used to analyze the data (α = .5).

RESULTS

Significant differences were observed within the groups in terms of the axial discrepancy (p = .022); group A had significantly higher amounts of axial discrepancy compared to group B (p = .001) and group C (p = .003). Preservation of the intact axial walls did not result in a statistically significant decrease in marginal (p = .21) and pulpal (p = .31) discrepancy values. Also, concerning the fracture resistance no significant difference was observed among the groups (p = .51).

CONCLUSION

Preservation of at least one of the axial walls could reduce the amount of the axial discrepancy and, therefore, improves the adaptation of the restoration. However, based on this study, it did not improve fracture resistance.

Finite Element Analysis of Stress in Bone and Abutment-Implant Interface under Static and Cyclic Loadings

Objectives

The success of implant treatment depends on many factors affecting the bone-implant, implant-abutment, and abutment-prosthesis interfaces. Stress distribution in bone plays a major role in success/failure of dental implants. This study aimed to assess the pattern of stress distribution in bone and abutment-implant interface under static and cyclic loadings using finite element analysis (FEA).

Materials and Methods

In this study, ITI implants (4.1×12 mm) placed at the second premolar site with Synocta abutments and metal-ceramic crowns were simulated using SolidWorks 2007 and ABAQUS software. The bone-implant contact was assumed to be 100%. The abutments were tightened with 35 Ncm preload torque according to the manufacturer's instructions. Static and cyclic loads were applied in axial (116 Ncm), lingual (18 Ncm), and mesiodistal (24 Ncm) directions. The maximum von Mises stress and strain values were recorded.

Results

The maximum stress concentration was at the abutment neck during both static and cyclic loadings. Also, maximum stress concentration was observed in the cortical bone. The loading stress was higher in cyclic than static loading.

Conclusion

Within the limitations of this study, it can be concluded that the level of stress in single-unit implant restorations is within the tolerable range by bone.

Out-of-plane permittivity of confined water

The dielectric properties of confined water is of fundamental interest and is still controversial. For water confined in channels with height smaller than h=8Å, we found a commensurability effect and an extraordinary decrease in the out-of-plane dielectric constant down to the limit of the dielectric constant of optical water. Spatial resolved polarization density data obtained from molecular dynamics simulations are found to be antisymmetric across the channel and are used as input in a mean-field model for the dielectric constant as a function of the height of the channel for h>15Å. Our results are in excellent agreement with a recent experiment [L. Fumagalli et al., Science 360, 1339 (2018)SCIEAS0036-807510.1126/science.aat4191].

Do Type and Shape of Scan Bodies Affect Accuracy and Time of Digital Implant Impressions?

OBJECTIVES

Reports concerning the accuracy of intraoral digital impression systems are limited. This study aimed to assess the effects of scan body types and shapes on digital impression accuracy and scanning time in all-on-four restorations.

METHODS

This in vitro study was conducted with two acrylic maxillary models. Two implant systems with different connection types (internal trilobe and external hexagon connection) were inserted according to the all-on-four design. Scanning was performed using Doowon, NT-Trading, and DESS scan bodies. Changes in implants' positions (ΔR) and angulation (ΔA), and the implants' distance from the reference pin (ΔD) compared with the actual model were determined. Scanning times were also measured and compared.

RESULTS

The effects of implant connections and scan bodies on ΔR and ΔA were significant (p ⟨0.05). Implant angulation could also affect ΔA (p=0.019). ΔD was only affected by scan body (p ⟨0.001). The three scan bodies were significantly different in terms of scanning time (p=0.001).

CONCLUSION

The results showed that scan body type and shape, and implant connection and angulation could affect digital impression accuracy in all-on-four restorations. For both internal and external connections, the NT-Trading and DESS scan bodies had the shortest and longest scanning times, respectively.

A novel missense mutation (c.1006C>T) of SPG20 gene associated with Troyer syndrome

The number of gene mutations involved in the hereditary spastic paraplegias is rapidly growing due to the expansion of the frontiers of genomic research by next-generation DNA sequencing platforms. Nevertheless, a comprehensive genetic diagnosis method remains yet unavailable for these diseases. In the current research, an 8-year-old boy with short stature and developmental delay impairment, from a nonconsanguineous family, was referred to our genetic lab. Firstly, based on the physician recommendation, the patient was evaluated by tandem mass spectrometry (MS/MS) for the quantitative examination of amino acids, and then the patient was genetically investigated by karyotype analysis and whole-exome sequencing (WES) technique. Subsequently, targeted Sanger sequencing was applied to confirm the presence of the candidate variant in all the members of the family and screening the other patients for Troyer syndrome. Analysis of inherited metabolic disorders by tandem MS/MS showed the state of all the family members as normal and also karyotyping indicated no chromosomal aberration in the patient. Further investigation by WES technique indicated a homozygous missense variant in the SPG20 gene, c.1006C[T. Targeted sequencing result of the mutation confirmed homozygote state for the affected case and a heterozygote genotype for his parents. The mutation was classified as pathogenic. Detection of novel variants especially pathogenic variantin the SPG20 gene was associated with Troyer syndrome, which encodes a multifunctional protein termed Spartin, assist in improving genotype-phenotype correlation of genetic variants and may facilitate initial diagnosis of Troyer syndrome.

Effect of Different Irrigants Applied After Post Space Preparation on Push-Out Bond Strength of a Self-Etch Resin Cement

OBJECTIVES

The aim was to investigate the effect of intracanal irrigants and agents on the bond strength of intraradicular fiber posts to dentin.

MATERIALS AND METHODS

Root canals of 72 decoronated single-rooted premolars were cleaned, shaped, and obturated with gutta-percha and AH26. The specimens were incubated at 37°C and 100% humidity for seven days. Next, the coronal 10 mm of the canals were prepared to receive size 2 D.T. Light fiber post, and the specimens were randomly allocated into six groups according to the irrigants used after post space preparation: normal saline (control group), 5.25% sodium hypochlorite (NaOCl)/15 seconds, 17% ethylenediaminetetraacetic acid (EDTA)/60 seconds, 2% chlorhexidine (CHX)/5 minutes, MTAD/5 minutes, and acid-etching/15 seconds. All canals were rinsed with normal saline and dried. Fiber posts were cemented using Panavia F2.0. After 24 hours, two mid-root slices of 1mm thickness were obtained from each specimen. Push-out bond strength test was performed in a universal testing machine at 0.5mm/minute. The maximum applied load was recorded, and the bond strength was calculated in megapascal (MPa). Data were analyzed by one-way analysis of variance (ANOVA) and Tukey's test.

RESULTS

The mean shear bond strengths of etched (53.21±12.11 MPa), MTAD (52.47±14.75 MPa) and EDTA (49.08±10.19 MPa) groups were significantly higher than that of the control group (39.82±10.04 MPa). The difference was marginally significant for CHX group (49.8±13.57 MPa) and not significant for NaOCl group (47.15±17.64 MPa).

CONCLUSIONS

Etching or irrigating the root canals with MTAD or EDTA after post space preparation increases the bond strength of Panavia F2.0 to dentin.

Effect of Repeated Firings on Microtensile Bond Strength of Bi-layered Lithium Disilicate Ceramics (e.max CAD and e.max Press)

AIM

To achieve acceptable contour, color, esthetics, and occlusal relations, the porcelain may be subjected to several firing cycles. This study sought to assess the effect of multiple firing cycles on the microtensile bond strength (MTBS) of lithium disilicate-based ceramics (e.max Press, e.max CAD).

MATERIALS AND METHODS

IPS e.max computer aided design (CAD) cores were fabricated using CAD/(Computer Aided Manufacturing (CAM)) technology, and IPS e.max Press cores were fabricated using the heat-pressing technique (12 × 12 × 4 mm(3)). Cores in each group were divided into three subgroups based on the number of firing cycles (three, five, and seven cycles). After porcelain application, the samples were sectioned into microbars and a total of 20 sound microbars in each group were subjected to tensile load in a microtensile tester at a crosshead speed of 1 mm/minute. Microtensile bond strength of the core to the veneering porcelain was analyzed using one-way analysis of variance (ANOVA). Pairwise comparisons were made using the Tukey's test (p < 0.05).

RESULTS

In the e.max CAD, the mean MTBS values were 22.07 ± 6.63, 34.68 ± 7.07, and 26.05 ± 10.29 MPa following three, five, and seven firing cycles respectively. These values for the e.max Press were 34.46 ± 9.28, 23.09 ± 5.02, and 31.26 ± 12.25 MPa respectively. There was significant difference in bond strength of e.max CAD (p < 0.003) and e.max Press (p < 0.002) based on the number of firing cycles.

CONCLUSION

Increasing the number of porcelain firing cycles decreased the bond strength of the core to the veneering porcelain in both ceramics.

CLINICAL SIGNIFICANCE

It is better to decrease the number of firing cycle as much as possible.

Comparison of Marginal Fit and Fracture Strength of a CAD/CAM Zirconia Crown with Two Preparation Designs

OBJECTIVES

The purpose of this in vitro study was to compare the marginal adaptation and fracture resistance of a zirconia-based all-ceramic restoration with two preparation designs.

MATERIALS AND METHODS

Twenty-four mandibular premolars were randomly divided into two groups (n=12); the conventional group received a peripheral shoulder preparation and the modified group received a buccal shoulder and proximal/lingual chamfer preparation. The marginal fit of the zirconia crowns (Cercon) was evaluated using a stereomicroscope. After cementation, load was applied to the crowns. The mean fracture load and the mean marginal gap for each group were analyzed using t-test (P=0.05).

RESULTS

The mean marginal gap was 71±16μm in the conventional group and 80±10μm in the modified group, with no significant difference (P=0.161). The mean fracture strength was 830±153N for the conventional group and 775±125N for the modified group, with no significant difference (P=0.396). All but one fracture occurred in the veneering ceramic.

CONCLUSION

Less aggressive preparation of proximal and lingual finish lines for the preservation of tooth structure in all-ceramic restorations does not adversely affect the marginal adaptation or fracture strength of the final restoration.

Nerve growth factor acts through the TrkA receptor to protect sensory neurons from the damaging effects of the HIV-1 viral protein, Vpr

Distal sensory polyneuropathy (DSP) with associated neuropathic pain is the most common neurological disorder affecting patients with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS). Viral protein R (Vpr) is a neurotoxic protein encoded by HIV-1 and secreted by infected macrophages. Vpr reduces neuronal viability, increases cytosolic calcium and membrane excitability of cultured dorsal root ganglion (DRG) sensory neurons, and is associated with mechanical allodynia in vivo. A clinical trial with HIV/AIDS patients demonstrated that nerve growth factor (NGF) reduced the severity of DSP-associated neuropathic pain, a problem linked to damage to small diameter, potentially NGF-responsive fibers. Herein, the actions of NGF were investigated in our Vpr model of DSP and we demonstrated that NGF significantly protected sensory neurons from the effects of Vpr. Footpads of immunodeficient Vpr transgenic (vpr/RAG1(-/-)) mice displayed allodynia (p<0.05), diminished epidermalinnervation (p<0.01) and reduced NGF mRNA expression (p<0.001) compared to immunodeficient (wildtype/RAG1(-/-)) littermate control mice. Compartmented cultures confirmed recombinant Vpr exposure to the DRG neuronal perikarya decreased distal neurite extension (p<0.01), whereas NGF exposure at these distal axons protected the DRG neurons from the Vpr-induced effect on their cell bodies. NGF prevented Vpr-induced attenuation of the phosphorylated glycogen synthase-3 axon extension pathway and tropomyosin-related kinase A (TrkA) receptor expression in DRG neurons (p<0.05) and it directly counteracted the cytosolic calcium burst caused by Vpr exposure to DRG neurons (p<0.01). TrkA receptor agonist indicated that NGFacted through the TrkA receptor to block the Vpr-mediated decrease in axon outgrowth in neonatal and adult rat and fetal human DRG neurons (p<0.05). Similarly, inhibiting the lower affinity NGF receptor, p75, blocked Vpr's effect on DRG neurons. Overall, NGF/TrkA signaling or p75 receptor inhibition protects somatic sensory neurons exposed to Vpr, thus laying the groundwork for potential therapeutic options for HIV/AIDS patients suffering from DSP.

Acrylic resin polymerization in direct contact to the abutment and the temperature at bone-implant interface: a pilot in vitro study

Three autopolymerizing acrylic resins were applied to a titanium alloy abutment connected to 2 different diameters of an implant. The implants were embedded in fresh iliac bone of sheep in a 37°C water bath. Temperature changes were recorded via embedded thermocouples at the cervical (T1) and apical (T2) regions of the implant surface. Polymerization temperature of acrylic resins did not seem to exceed the critical threshold of 47°C.

The effect of background and ceramic thickness on the color of an all-ceramic restorative system

OBJECTIVE

Evaluation of the color change of a semileucent ceramic system with different core-veneer thicknesses and backgrounds.

MATERIALS AND METHODS

Thirty disk-shaped specimens with different thicknesses of core-veneer were prepared with IPS-Empress 2 and IPS-Eris glass ceramic and four backgrounds were prepared.

RESULTS

Color differences were significantly influenced by total ceramic thicknesses and backgrounds (p < 0.001).

CONCLUSION

Thickness and backgrounds caused a detectable color mismatch in clinically relevant core-veneer thicknesses of IPS Empress 2.

MEFV mutations in Iranian Azeri Turkish patients with familial Mediterranean fever

Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disorder with more than 60 disease-associated mutations in the responsible gene, MEFV. In the present study, we determined 15 MEFV mutations in Iranian Azeri Turkish FMF patients. Five hundred and twenty-four unrelated patients were tested for 15 known mutations in the MEFV gene using amplification refractory mutation system-polymerase chain reaction and polymerase chain reaction-restriction fragment length polymorphism methods. Thirty-five different genotypes were characterized among the studied patients. Of the alleles investigated, the most common mutation was p.M694V (42.4%), followed by p.V726A (17%), p.E148Q (16.2%), and p.M680I (c.2040G>C) (15.2%). The p.R761H mutation (4.7%) was found to be the most frequent among the rare mutations. The mutations p.M680I (c.2040G>A), p.I692del, p.M694del and p.K695R were not found in this cohort. The remaining mutations account for 7.7% of the identifiable mutations. Five different types of complex alleles were also identified. The results show the diversity and the frequency of the mutations in the Iranian Azeri Turkish FMF patients. The p.R761H mutation is rather prevalent in Azeri Turks; therefore, it should be included in the routine molecular diagnosis of FMF patients from this ethnic group.

Postoperative junctional ectopic tachycardia (JET)

Postoperative junctional ectopic tachycardia (JET) is a potential life-threatening tachycardia that mainly occurs after surgical correction of congenital heart defects. The arrhythmia itself or the related treatment has significant clinical impact on the postoperative course and intensive care stay. In general, JET is a self-limiting disorder that usually resolves within one week. However, JET occurs usually within the first 24 to 48 hours after corrective surgery, when systolic and diastolic function of the heart is impaired. Thus, the rapid heart rate leads to an acute further deterioration of cardiac output that requires adequate treatment. The diagnosis of JET is made by the typical ECG-appearance with narrow QRS-configuration at a rate of 170 to 260 bpm and AV-dissociation. A variety of different therapeutic strategies have been tested in postoperative and congenital/spontaneous JET. Treatment success is usually defined as a stable decrease in the ventricular rate below 140-150/min, the possibility of atrial pacing and thereby the improvement of cardiac output. Optimal success is the reinstitution of sinus rhythm. Many of the treatment strategies reported are based on specific institutional treatment protocols. These include conventional supportive treatment, specific medical antiarrhythmic therapy, specific forms of pacing and surface cooling. Today, the administration of high doses of amiodarone usually leads to adequate control of the rate and enables pacing. Surgical intervention or catheter ablation of the HIS-bundle is rarely necessary. This article reviews the literature about JET over the past years and offers a specific treatment protocol.

Quality assurance of paediatric cardiac surgery: a prospective 6-year analysis

OBJECTIVE

To audit effective quality assurance methods to monitor outcomes following paediatric cardiac surgery at a single institution.

METHODS

All patients undergoing cardiac surgery from January 1996 to December 2001 were enrolled prospectively. Patients were stratified by complexity of surgical procedure into four groups, with Category 4 being the most complex procedure. Outcome measures included death, length of admission and morbidity from complications.

RESULTS

A total of 1815 patients underwent 1973 surgical procedures. Of these, 1447 (73.3%) were cardiopulmonary bypass procedures, and 543 (27.5%) were more complex (Category 3 and 4) procedures. Median patient age was 3.5 years (range, 1 day-20 years) and patient weight 15.0 kg (range, 900 g to 90 kg). Sixty-six patients (3.6%) died during the study period. Of the procedures in 1996, 22.7% were classified as complex compared with 29.2% of procedures in 2001. The annual surgical mortality ranged from 1.9-4.7% (P = 0.20), and when mortality was adjusted for complexity of surgery, there was no significant yearly variation in the mortality rate (P = 0.57). Analysis of individual surgeon's results showed no significant difference in the mortality rate by complexity of surgery performed (P = 0.90). Mean ventilation times did not change significantly over time (P = 0.79). The yearly incidence of significant neurological complications ranged from 0.6% to 4.5% and the incidence of arrhythmias from 4.2% to 8.0%. No difference was detected between the years.

CONCLUSIONS

Stratifying complexity of surgery proved valuable in monitoring surgical outcomes and detecting differences in performance over time as large subgroups were created for analysis.

Both beta(2)- and beta(1)-adrenergic receptors mediate hastened relaxation and phosphorylation of phospholamban and troponin I in ventricular myocardium of Fallot infants, consistent with selective coupling of beta(2)-adrenergic receptors to G(s)-protein

BACKGROUND

In adult human heart, both beta(1)- and beta(2)-adrenergic receptors mediate hastening of relaxation; however, it is unknown whether this also occurs in infant heart. We compared the effects of stimulation of beta(1)- and beta(2)-adrenergic receptors on relaxation and phosphorylation of phospholamban and troponin I in ventricle obtained from infants with tetralogy of Fallot.

METHODS AND RESULTS

Myocardium dissected from the right ventricular outflow tract of 27 infants (age range 21/2 to 35 months) with tetralogy of Fallot was set up to contract 60 times per minute. Selective stimulation of beta(1)-adrenergic receptors with (-)-norepinephrine (NE) and beta(2)-adrenergic receptors with (-)-epinephrine (EPI) evoked phosphorylation of phospholamban (at serine-16 and threonine-17) and troponin I and caused concentration-dependent increases in contractile force (-log EC(50) [mol/L] NE 5.5+/-0.1, n=12; EPI 5.6+/-0.1, n=13 patients), hastening of the time to reach peak force (-log EC(50) [mol/L] NE 5.8+/-0.2; EPI 5.8+/-0.2) and 50% relaxation (-log EC(50) [mol/L] NE 5.7+/-0.2; EPI 5.8+/-0.1). Ventricular membranes from Fallot infants, labeled with (-)-[(125)I]-cyanopindolol, revealed a greater percentage of beta(1)- (71%) than beta(2)-adrenergic receptors (29%). Binding of (-)-epinephrine to beta(2)-receptors underwent greater GTP shifts than binding of (-)-norepinephrine to beta(1)-receptors.

CONCLUSIONS

Despite their low density, beta(2)-adrenergic receptors are nearly as effective as beta(1)-adrenergic receptors of infant Fallot ventricle in enhancing contraction, relaxation, and phosphorylation of phospholamban and troponin I, consistent with selective coupling to G(s)-protein.

The stentless xenograft aortic valve: The wheel turns around

BACKGROUND

A brief overview of the historical pathways of both stented and stentless porcine xenografts is presented in order to understand the return to and continuing clinical use of stentless devices. In addition, 7-11 years of durability with various models of stentless porcine valves has now accumulated and is beginning to be of relevance in determining the future place of this xenograft. Stentlessness and anticalcium agents, coupled with the poor results of stented xenografts in certain patient groups, have led to a resurgence of the clinical use of stentless xenograft valves for aortic valve replacement. An overview of the present state and future of stentless valves is given.

METHODS

At both The Prince Charles Hospital and St Andrew's War Memorial Hospital, Queensland, Australia, 307 patients have received the Model 300 CryoLife-O'Brien stentless composite aortic xenograft from December 1992 to February 2000. Associated procedures were required in 56% of patients (mostly coronary artery bypass, mean 2.4 grafts, in 144 patients (47%) and left ventricular myomectomy in 34 patients (11%)).

RESULTS

The hospital mortality (four early deaths) has been 1.3 +/- 1% (CL 95%) and the follow-up 100% for this analysis. The mean patient age was 73 years (range 57-89 years with 16% being 80 years and over). Morbid events have included six perivalvar leaks: four trivial and identified only on echo Doppler (no clinical murmurs) and two patients requiring reoperation at 10 days and 12 weeks with simple successful repair verified on subsequent echocardiograms. Of the 307 patients over the 7 year period, three valves only have been explanted, two for endocarditis at 1.5 and 3.5 years and one for possible technically induced structural failure at 15 months (probable needle damage). With this exception, there has been as yet no other intrinsic leaflet failure. Four early thromboembolic events (4 days-5 weeks) in patients with atrial fibrillation (no anticoagulants used postoperatively with the first 80 patients) constituted the important early morbid events. Late mortality of this elderly patient cohort has occurred in 27 patients over 7 years of maximum follow-up. One death (endocarditis) has been valve related at 5 years. Serial echocardiography (some 700 echoes in the study of this valve) has demonstrated a mean gradient of 7-9 mmHg with a very low incidence of trivial incompetence (96%) on Doppler examination with implant valve sizes ranging from 21 to 29 mm. One patient had significant regurgitation requiring reoperation. There has been no progression of either incompetence or stenosis of the remaining patients in this follow-up, now into the eighth postoperative year.

CONCLUSION

The early and intermediate results appear excellent in this elderly patient cohort. Nevertheless, important surveillance is obviously required to determine the durability at 10-12 years, a crucial time when stented porcine xenografts began to show an obvious failure rate from structural deterioration, in the middle and elderly aged patient cohort. An attempt is made to outline the future of this type of stentless xenograft and to justify that its cautious use should probably be extended down to the over 50 year age patient cohort.

Late complications of tissue glues in aortic surgery

BACKGROUND

Tissue glues are used in cardiothoracic surgery as an adjunct to operative procedures where tissues are frail, as in aortic dissection, or where added hemostasis is required. This study was undertaken to review the use of tissue glue in our institution over a 5.5-year period. The aim of the study was to identify any potentially glue-related complications.

METHODS

A review of tissue glue use for the period from January 1993 to September 1998 was performed and pre-, intra-, and postoperative parameters were collected. After some unusual surgical findings, of special interest was a range of pathology found at late reoperation.

RESULTS

A total of 67 cases of tissue glue use were identified, with the majority of operations for type A dissection (76%). There were two intraoperative deaths. Twenty-seven of 65 patients (41%) required 29 further open chest operations; of these, 17 were for acute problems of bleeding or tamponade. Twelve patients (18%) underwent late reoperations months to years later. Nine of these patients, concentrated in two operative groups (7 patients with aortic valve resuspension and 2 patients who had undergone "switch" operations for transposition of great vessels), displayed complications related to the application of gelatin-resorcinol-formaldehyde (GRF) tissue glue.

CONCLUSIONS

Indications for tissue glues in cardiothoracic surgery must be carefully considered. We have reviewed our use of some tissue glues in acute type A aortic dissections and in pediatric cardiac patients and have discontinued the use of GRF glues because of unsatisfactory long-term complications.

[Medico-surgical management of childhood cardiopathy: results of the Liège experience]

OBJECTIVE

Evaluation of the results obtained in the management of congenital heart diseases in Liège.

MATERIAL AND METHODS

We evaluated the results, the mortality and the morbidity of diagnostic and interventional cardiac catheterization, and of the cardiac surgery in the 123 cardiac children who were referred to us during the three first years of operation of our medico-surgical team.

RESULTS

89 children underwent a catheterization, including 12 therapeutic interventions, whereas 68 were operated. In the two domains, the results are completely comparable with those of the established centers.

CONCLUSIONS

The widening of the activity of paediatric cardiology and the creation of an activity of pediatric cardiac surgery in Liège appeared important to us for the quality of management of the cardiac children. This goal could be reached only if our results were comparable with those of the literature. The bet seems to be held. The ultimate objective is to contribute by an adequate policy of management to the quality of life and the health of the cardiac children.

Mid-term results of the Ross procedure

METHODS

Fifty patients underwent a Ross operation between June 1991 and October 1996. Preoperative diagnosis was: congenital aortic valve disease (31 patients), complex left ventricular outflow tract (LVOT) obstruction (11 patients), outgrowth of a small aortic valve prosthesis (five patients) and valve endocarditis (three patients). Half of the interventions were reoperations. All operations were root replacements. A pulmonary homograft was used in 45 patients. An aorticoventriculoplasty was combined with the root replacement in the 16 patients with LVOT obstruction and a too small aortic valve prosthesis. An enlargement or reduction plasty of the ascending aorta was necessary in seven patients.

RESULTS

The mean age was 20.9 years (range: 2.5-54 years). The mean follow up was 34.2 +/- 21 months and was 94% complete. Two patients died after 8 days (low cardiac output due to myocardial fibrosis) and 17.4 months (sudden death), respectively, resulting in a survival of 95 +/- 4% at 4 years. Those two deaths occurred in the group of patients undergoing Ross procedure and aorticoventriculoplasty. Two autografts were replaced after respectively 2 days (technical failure) and 44 months (progressive root dilatation) resulting in a reoperation-free incidence of 93 +/- 6% at 4 years. Other postoperative major complications occurred in six patients. All survivors had regular echo-Doppler examination. All autografts except one had a systolic gradient below 10 mmHg at the last examination. Thirty-four autografts had no leak, ten showed grade 1-2 regurgitation. Two patients showed a higher than grade 3 regurgitation: one leak remains stable with normal left ventricular dimensions and function, one autograft was replaced by a mechanical valve.

CONCLUSION

This experience demonstrates that the medium-term results of the Ross procedure are excellent even in complex LVOT obstructions.

Use of computational fluid dynamics in the design of surgical procedures: application to the study of competitive flows in cavo-pulmonary connections

Computational fluid dynamic methods based on a finite-element technique were applied to the study of (1) competition of flows in the inferior and superior venae cavae in total cavopulmonary connection, and (2) competition between flow in the superior vena cava and forward flow from a stenosed pulmonary artery in bidirectional cavopulmonary anastomosis. Models corresponding to various degrees of offsetting and shape of the inferior vena caval anastomosis were simulated to evaluate energy dissipation and flow distribution between the two lungs. A minimal energy loss with optimal flow distribution between the two lungs was obtained by enlarging the inferior vena caval anastomosis toward the right pulmonary artery. This modified technique of total cavopulmonary connection is described. A computational model of the operation was developed in an attempt to understand the mechanisms of postoperative failure. In tight pulmonary artery stenosis (75%), the pulsatile forward flow is primarily directed to the left pulmonary artery, with little influence on superior vena caval pressure and the right pulmonary artery. Pulsatile forward flows corresponding to 15%, 30%, 45%, and 60% of the systemic artery output increased the mean pulmonary artery and superior vena caval pressures by 1, 1.7, 2.4, and 3.6 mm Hg, respectively. Although the modeling studies were not able to determine the cause of postoperative failure, they emphasize the impact of local geometry on flow dynamics. More simulations are required for further investigation of the problem.

An unusual case of cor triatriatum: clinical presentation and the haemodynamics of a rare anomaly

The case of a 24-year-old woman with cor triatriatum sinister and a persistent left superior vena cava connected to the junction of the left upper pulmonary vein and left atrium is reported. A diagnosis of partial anomalous pulmonary venous return had been made and the patient underwent surgery. Inspection of the left atrium revealed a complex form of left triatrial heart. The general haemodynamics of the malformation are discussed, with particular emphasis on the features accounting for variation in the clinical presentation. This rare anomaly often remains undiagnosed before surgery and should be considered whenever obstruction of pulmonary venous flow above the mitral valve is not explained by pulmonary vein stenosis, mitral or mitral valve-linked abnormalities, atrial tumours or anomalous pulmonary venous drainage with high resistance to flow.

Studies on trematodes of the family Heterophyidae (Odhner, 1914) in Iran: 1. Preliminary epidemiological surveys in man and carnivores in Khuzestan

Trematodes of the family Heterophyidae in man and carnivores were studied in Khuzestan, south-west Iran. Eight hundred and eleven stool samples from a population of 3400 in 13 villages in a swampy area located in central Khuzestan were examined by the formalin-ether concentration technique. The following helminths were found: Ascaris lumbricoides 7%, Trichostrongylus spp. 53%, hookworms 4+, Trichuris trichiura 5%, Hymenolepis nana 12% and heterophyid spp. 8%. Post-mortem examination of carnivores revealed that 14.2% of jackals, 33.3% of foxes and 2.5% of dogs were infected with heterophyids, namely Metagonimus yokogawai, Heterophyes heterophyes and H. katsuradai. The freshwater snails Melanoides and Melanopsis spp. and brackish water fishes Barbus spp. and Mugil spp. were thought to be the intermediate hosts of these flukes in this area. This is the first report of heterophyid infection in man and carnivores in Iran.

Prevalence of intestinal helminths in Khuzestan, Southwest Iran, 1977

Large scale studies were performed to determine the prevalence of various intestinal helminth infections in urban and rural areas of Khuzestan Province, southwest Iran. A total of 16,361 stool samples from people in 105 villages and 14 small towns were examined by the formalin-ether concentration method. Ascaris, hookworms, Trichostrongylus, Trichuris, and Hymenolepis nana showed the highest prevalence. Hookworms and Trichostrongylus were twice as prevalent in rural than in urban areas; in contrast, H. nana was more prevalent in urban areas while the level of Ascaris infections was not significantly different. The intensity of Ascaris and hookworm infections, as estimated by the number of eggs/g of feces, was higher in rural than in urban areas.

Evaluation of the effect of different methods of control of soil-transmitted helminths in Khuzestan, southwest Iran

Three methods of control of soil-transmitted helminths, namely, sanitation, mass-treatment, and sanitation plus mass-treatment, were tried in 15 villages in Khuzestan, southwest Iran. Stool samples from the inhabitants of each village were examined both quantitatively and qualitatively just before starting each control method and again about 4 years later, except for the inhabitants of one village whose stools were re-examined 7 months after moving to a new settlement. Sanitation measures consisted of one latrine for each family and the provision of a sanitary water supply in each village. The drugs piperazine and bephenium hydroxynapthoate were administered alternately every 3 months. The reduction in rates of infection with Ascaris, hookworm, and Trichostrongylus spp., respectively, for the above mentioned methods were as follows: sanitation alone, 28%, 4% and 30%; mass-treatment alone, 84%, 73%, and 31%; sanitation plus mass-treatment, 79%, 69%, and 30% and in the newly constructed village, 76%, 21%, and 38%. In a control group corresponding reductions were 19%, 11%, and 31%. The percentage of egg reduction in persons still infected with these three parasites was, respectively, as follows: mass-treatment plus sanitation, 88%, 88%, and 53%; mass-treatment alone, 90%, 87%, and 37%; sanitation alone, 60%, 26%, and 0.6%; in the newly constructed village, 87%, 78%, and 39%; and in the control group, 29% increased 12%, and 24.5%. The significance of these findings is discussed.

Comparative studies on the evaluation of the effect of new anthelminthics on various intestinal helminthiasis in Iran. Effects of anthelminthics on intestinal helminthiasis

The effect of pyrantel pamoate, levamisole, mebendazole, thiabendazole and bephenium hydroxynaphthoate on various intestinal helminths were evaluated among the inhabitants of four villages in the Dezful area southwest of Iran. A total number of 328 persons, all infected simultaneously with Ascaris and hookworm (Ancylostoma duodenale) and 49.2% with Trichostrongylus spp., were randomly divided into six groups. One group was kept as the control and the other five were each treated with one compound. Follow-up examinations showed that all of the drugs used were highly effective on Ascaris, and the differences in the cure rate were not statistically significant except for bephenium hydroxynaphthoate which showed a lower cure rate. For hookworm, cure rates of 100, 90, and 85% were observed with levamisole, pyrantel pamoate and bephenium hydroxynaphthoate, respectively. Cure rates observed with mebendazole and thiabendazole were 35 and 51%, respectively. For Trichostrongylus, the highest cure rate was achieved with levamisole, followed by thiabendazole and mebendazole. While the percentage of people showing side-effects was rather low for all drugs, thiabendazole and bephenium hydroxynaphthoate produced a higher, and levamisole a lower, percentage of side effects.