Color stability of resin used for caries infiltration after exposure to different staining solutions

PURPOSE : The aim of this study was to investigate the staining behavior of demineralized enamel infiltrated by low-viscosity resin. METHODS AND MATERIALS : Bovine enamel/dentin cylindrical samples (3 × 2 mm) were assigned into four groups (n=45) according to the enamel treatment: sound enamel (control), demineralization + artificial saliva, demineralization + daily application of 0.05% NaF, demineralization + resin infiltration (Icon, DMG). Artificial white spot lesions were produced in groups with demineralization. After the treatments, color was assessed by spectrophotometry, using the CIE L*a*b* system. The specimens (n=15) were then immersed in deionized water, red wine, or coffee for 10 minutes daily for eight days. Color was measured again, and the specimens were repolished with sandpaper discs. The final color was assessed. Data were analyzed by two-way analysis of variance and Tukey tests (α=0.05). A paired t-test was used for comparison between staining and repolishing conditions. RESULTS : There were significant differences for surface treatment and dye after staining and repolishing. Immersion in wine and coffee resulted in significantly increased color alteration (ΔE) compared with water (p=0.001). The resin-infiltrated group exhibited the highest staining values (p=0.001). The repolishing procedures resulted in significantly decreased color change.

CONCLUSION

The exposure of specimens to colored solutions resulted in significant color alteration. The demineralized enamel treated with resin infiltration showed significantly higher staining than all other tested groups; however, the repolishing of the specimens minimized the staining effect.

Mental distress and effort to engage an image-guided navigation system in the surgical training of endoscopic sinus surgery: a prospective, randomised clinical trial

The use of image-guided navigation systems in the training of FESS is discussed controversy. Many experienced sinus surgeons report a better spatial orientation and an improved situational awareness intraoperatively. But many fear that the navigation system could be a disadvantage in the surgical training because of a higher mental demand and a possible loss of surgical skills. This clinical field study investigates mental and physical demands during transnasal surgery with and without the aid of a navigation system at an early stage in FESS training. Thirty-two endonasal sinus surgeries done by eight different trainee surgeons were included. After randomization, one side of each patient was operated by use of a navigation system, the other side without. During the whole surgery, the surgeons were connected to a biofeedback device measuring the heart rate, the heart rate variability, the respiratory frequency and the masticator EMG. Stress situations could be identified by an increase of the heart rate frequency and a decrease of the heart rate variability. The mental workload during a FESS procedure is high compared to the baseline before and after surgery. The mental workload level when using the navigation did not significantly differ from the side without using the navigation. Residents with more than 30 FESS procedures already done, showed a slightly decreased mental workload when using the navigation. An additional workload shift toward the navigation system could not be observed in any surgeon. Remarkable other stressors could be identified during this study: the behavior of the supervisor or the use of the 45° endoscope, other colleagues or students entering the theatre, poor vision due to bleeding and the preoperative waiting when measuring the baseline. The mental load of young surgeons in FESS surgery is tremendous. The application of a navigation system did not cause a higher mental workload or distress. The device showed a positive effort to engage for the trainees with more than 30 FESS procedures done. In this subgroup it even leads to decreased mental workload.

Impact of navigated-control assistance on performance, workload and situation awareness of experienced surgeons performing a simulated mastoidectomy

BACKGROUND

Navigated control (NC) is an advanced image-guided navigation system that provides an additional control function to enhance patient safety. It automatically stops the surgical instrument if it comes close to critical anatomical structures that need to be protected during surgery. The purpose of this study was to explore the human performance consequences of computer-based navigated control assistance.

METHODS

Seven experienced surgeons conducted a simulated mastoidectomy manually and with support of the NC system. The impact on surgical performance, workload and situation awareness was analysed.

RESULTS

NC support led to a better quality of surgical outcome and a lower level of physiological effort during surgery. Cost effects were reflected in reduced time efficiency and an increased subjectively experienced workload.

CONCLUSION

The results demonstrate the potential of NC support in terms of lower workload and enhanced patient safety. Cost effects might be reduced by remodelling the control function.

Evaluation of an image-guided navigation system in the training of functional endoscopic sinus surgeons. A prospective, randomised clinical study

INTRODUCTION

Many sinus surgeons report improved spatial orientation after using a navigation system. This study investigates the surgical, ergonomic and economic aspects of using a navigation system in training and teaching.

MATERIALS AND METHODS

Eight rhino-surgeons in training and 32 patients with bilateral diseases of the paranasal sinus system were included. After randomisation, one patient`s side was operated on with a navigation system while the other side was operated on without navigation. It was monitored how often the surgeon used the navigation pointer and then changed the procedures. A standardised and validated interview recorded the cognitive load when using the navigation system and the application efficiency.

RESULTS

The operations lasted on average 16 minutes longer with the navigation. Five paranasal sinuses could not be found in the control group without navigation. In only 10-13% of cases did the surgical procedure change after the use of the pointer. Most of the surgeons admitted that particular steps of the operation were more reliable and safer to carry out with the navigation system. The general trust in the system rose in proportion to intraoperative accuracy and repeated use.

CONCLUSION

Overall, there was an overwhelming level of trust in the navigation system. Trainee sinus surgeons seeing their more experienced colleagues using a navigation device tend to overestimate the possibilities of the system and to underestimate the risks. The assistance system was used particularly effectively in the group of slightly more experienced surgeons. In this group, the additional expenditure of time was less and the navigation substantially contributed to reinforcing the anatomical sense of direction.

Comparison of generic to branded pentavalent antimony for treatment of new world cutaneous leishmaniasis

The cost of generic pentavalent antimony (generic stibogluconate) is approximately one-sixth that of branded pentavalent antimony (stibogluconate in the form of Pentostam or meglumine antimoniate in the form of Glucantime. We compared generic stibogluconate to Pentostam and Glucantime for the treatment of cutaneous leishmaniasis patients in Bolivia and Colombia. For all 114 patients, the per-protocol cure rates were 83-91% and the intent-to-treat cure rates were 75-83%. The highest values were in the generic stibogluconate group. The incidence of pancreatic enzyme abnormalities was 48-88% and the incidence of liver enzyme abnormalities was 48-87%. The lowest incidences were in the generic stibogluconate group. The efficacy and tolerance of inexpensive generic stibogluconate appears comparable to branded formulations for the treatment of cutaneous leishmaniasis in these endemic regions.

Miltefosine for New World Cutaneous Leishmaniasis

The oral agent miltefosine has demonstrated a >95% cure rate in Indian visceral leishmaniasis. We performed a large, placebo-controlled study of miltefosine therapy (2.5 mg/kg per day orally for 28 days) against cutaneous leishmaniasis in Colombia and Guatemala. In regions in Colombia where Leishmania vianna panamensis is common, the per-protocol cure rates for miltefosine and placebo were 91% (40 of 44 patients) and 38% (9 of 24). These values are similar to historic values for the antimony standard of care and placebo. In regions in Guatemala where L. v. braziliensis and L. mexicana mexicana are common, the per-protocol cure rates were 53% (20 of 38) for miltefosine and 21% (4 of 19) for placebo. The miltefosine rate was lower than historic antimony cure rates of >90%. Miltefosine was well tolerated. Miltefosine is a useful oral agent against cutaneous leishmaniasis due to L. v. panamensis in Colombia but not against leishmaniasis due to L. v. braziliensis in Guatemala.

Biodegradation of 1,1,1,2-tetrachloroethane under methanogenic conditions

Chlorinated aliphatic hydrocarbons are widely used as solvents and as intermediates in chemical synthesis, so they can be found in industrial wastewaters and released to the environment where they became a serious health risk due to their toxic properties and high chemical stability. Most of these compounds are xenobiotic and recalcitrant to biodegradation. In this article we report the effect of different co-substrates in the 1,1,1,2-tetrachloroethane (1,1,1,2-TeCA) degradation by anaerobic granular sludge, and its degradative pathway. Our results show that this compound is easy and rapidly biodegradable under methanogenic conditions, even in the absence of external electron donors. 1,1,1,2-TeCA is equimolecularly degraded to 1,1-dichloroethene (1,1-DCE) by reductive dichloroelimination. 1,1-DCE is only completely biodegraded in the presence of lactic acid as co-substrate. Although 1,1,1,2-TeCA can be apparently removed by autoclaved granular sludge, the compound is not transformed but retained inside the granules. The primary biodegradation of 1,1,1,2-TeCE to 1,1-DCE is a biotic process mediated by anaerobic bacteria.

Heparin-induced thrombocytopenia with thromboembolic complications: meta-analysis of 2 prospective trials to assess the value of parenteral treatment with lepirudin and its therapeutic aPTT range

This meta-analysis focuses on 2 prospective studies in patients with heparin-induced thrombocytopenia (HIT) and thromboembolic complication (TEC) who were treated with lepirudin (n = 113). Data were compared with those of a historical control group (n = 91). The primary endpoint (combined incidence of death, new TEC, and limb amputation) occurred in 25 lepirudin-treated patients (22.1%; 95% CI, 14.5%-29.8%): 11 died (9.7%; 95% CI, 4.9%-16.8%), 7 underwent limb amputation (6.2%; 95% CI, 2.5%-12.3%), and 12 experienced new TEC (10.6%; 95% CI, 5.8%-18.3%). The risk was highest in the period between diagnosis of HIT and the start of lepirudin therapy (combined event rate per patient day 6.1%). It markedly decreased to 1.3% during lepirudin treatment and to 0.7% in the posttreatment period. From the start of lepirudin therapy to the end of follow-up, lepirudin-treated patients had consistently lower incidences of the combined endpoint than the historical control group (P =.004, log-rank test), primarily because of a reduced risk for new TEC (P =. 005). Thrombin-antithrombin levels in the pretreatment period (median, 43.9 microg/L) decreased after the initiation of lepirudin (at 24 hours +/- 6 hours; median, 9.18 microg/L.) During treatment with lepirudin, aPTT ratios of 1.5 to 2.5 produced optimal clinical efficacy with a moderate risk for bleeding, aPTT ratios lower than 1. 5 were subtherapeutic, and aPTT levels greater than 2.5 were associated with high bleeding risk. Bleeding events requiring transfusion were significantly more frequent in patients taking lepirudin than in historical control patients (P =.02). In conclusion, this meta-analysis provides further evidence that lepirudin is an effective and acceptably safe treatment for patients with HIT.

Lepirudin (recombinant hirudin) for parenteral anticoagulation in patients with heparin-induced thrombocytopenia. Heparin-Associated Thrombocytopenia Study (HAT) investigators

BACKGROUND

We prospectively investigated lepirudin for further parenteral anticoagulation in patients with heparin-induced thrombocytopenia (HIT).

METHODS AND RESULTS

Patients with confirmed HIT (n=112) received lepirudin according to need for 2 to 10 days (longer if necessary): A1, treatment: 0.4 mg/kg IV bolus, followed by 0.15 mg. kg(-1). h(-1) intravenous infusion, n=65; A2, treatment in conjunction with thrombolysis: 0.2 mg/kg, followed by 0.10 mg. kg(-1). h(-1), n=4; and B, prophylaxis: 0.10 mg. kg(-1). h(-1), n=43. Outcomes from 95 eligible lepirudin-treated patients were compared with those of historical control patients (n=120). Complete laboratory response (activated partial thromboplastin time ratio >1.5 with </=2 dose increases and platelet count normalization by day 10) was achieved in 65 lepirudin-treated patients (69.1%; 95% CI, 59. 3% to 78.3%). At 2 weeks after cessation of lepirudin, 11 patients died (9.8%), 10 underwent limb amputation (8.9%), and 20 suffered a new thromboembolic complication (17.9%). The average combined event rate per patient-day decreased from 5.1% in the pretreatment period to 1.5% in the treatment period. Thirty-five days after HIT confirmation, fewer lepirudin-treated patients than historical control patients had experienced >/=1 outcome (cumulative incidence 30.9% versus 52.1%; relative risk [RR] 0.71; P=0.12, log-rank test). Bleeding events were more frequent in the lepirudin group than the historical control group (cumulative incidence at 35 days, 44.6% versus 27.2%; RR 2.57; P=0.0001, log-rank test). No difference was observed in bleeding events requiring transfusion (cumulative incidence at 35 days, 12.9% versus 9.1%; RR 1.66; P=0.23, log-rank test); no intracranial bleeding was observed in the lepirudin group.

CONCLUSIONS

Lepirudin effectively prevents death, limb amputations, and new thromboembolic complications and has an acceptable safety profile in HIT patients. Treatment should be initiated as soon as possible if HIT is suspected.

[Microsurgical reconstruction of the head and neck: experience of 63 free flaps]

The authors present the experience of 63 clinical cases of microsurgical reconstruction of the head and neck. These reconstructions were accomplished by different microvascular free flaps which were selected according to the type, size and location of the defects. Fasciocutaneous, osteofasciocutaneous, adipofascial, myo, myocutaneous, myosseous, jejunum and great omentum flaps were applied. The etiology was traumatic in 10 cases, tumoral in 41 cases, congenital in 7 cases, iatrogenic in 3 cases and infectious in 2 cases. The reconstructed anatomical regions were the scalp in 6 cases, the skull base in 1 case, the orbit in 3 cases, the nose in 1 case, the hemiface in 7 cases, the lips in 1 case, the intraoral cavity in 21 cases, the mandible in 8 cases, the intraoral cavity plus mandible in 11 cases and the cervical esophagus in 1 cases. An analysis was made of surgical times, selection and survival rate of the free flaps and the morphofunctional quality of the reconstructions. Considering the good quality of reconstructions, the amelioration of quality of life and the low morbidity in these patients, microvascular free flaps are considered a first choice technique for head and neck reconstruction when the size and location of the defect prevents the use of local flaps.

Recombinant hirudin as a periprocedural antithrombotic in coronary angioplasty for unstable angina pectoris

Percutaneous transluminal coronary angioplasty is often complicated by thrombotic abrupt vessel closure in patients with unstable angina pectoris. The present multicentre trial was performed to determine the feasibility of two-dose regimens of recombinant hirudin (r-hirudin) compared to standard heparin in patients undergoing coronary angioplasty for unstable angina, and to investigate the effects of the different treatment regimen on markers of coagulation activation. At five participating centres, 61 patients were randomly enrolled in one of two sequential groups of r-hirudin (group 1: 0.3 mg.kg-1 i.v. bolus, 0.12 mg.kg-1.h-1 i.v. infusion; 21 patients; group 2: 0.5 mg.kg-1 i.v. bolus, 0.24 mg.kg-1.h-1 i.v. infusion; 19 patients) or in a heparin control group (150 IU.kg-1 i.v. bolus, 20 IU.kg-1.h-1 i.v. infusion; 21 patients). Antithrombotic therapy was started immediately before coronary angioplasty and continued for 24 h. This was followed by a low-dose anticoagulant infusion for another 24 h (r-hirudin: 0.04 mg . kg-1 . h-1; heparin: 7 IU . kg-1 . h-1). Activated partial thromboplastin time, r-hirudin plasma concentrations by both immunological and functional assay, thrombin-hirudin complex, thrombin-antithrombin III complex, soluble fibrin, and prothrombin fragment 1 + 2 were closely monitored. The median partial thromboplastin time prolongations at 24 h vs baseline were found to be 1.9-fold and 2.3-fold in r-hirudin group 1 and dose group 2, respectively, and 3.0-fold in the heparin group. There was a dose-dependent correlation between partial thromboplastin time and the r-hirudin plasma levels (r = 0.61). In five of 21 patients of dose group 1, three of 19 patients of dose group 2, and 10/21 patients of the heparin group, partial thromboplastin time values exceeding the predefined target range prompted an interruption of the infusion. One major bleeding complication occurred in dose group 2. The functional assay for the estimation of r-hirudin plasma concentrations showed excellent correlations to the immunological technique (r = 0.99). Differences between the thrombin-hirudin complex levels could not be observed. Increased concentrations of thrombin-antithrombin III complex, soluble fibrin, and prothrombin fragment 1 + 2 were seen 4-8 h after coronary angioplasty and after reduction of the high-dose therapy in dose group 1 when compared with dose group 2 and the heparin group, respectively. Based on coagulation tests the present study showed the feasibility of a periprocedural antithrombotic regimen with r-hirudin for patients undergoing coronary angioplasty for unstable angina. In addition to the partial thromboplastin time the determination of r-hirudin plasma levels by a chromogenic substrate assay considerably improves the monitoring of therapy. The lower dose r-hirudin regimen seems to be suboptimal as periprocedural anticoagulation in coronary angioplasty patients as indicated by markers of thrombin generation and thrombin activity.

Recombinant hirudin (HBW 023) prevents troponin T release after coronary angioplasty in patients with unstable angina

OBJECTIVES

This study was performed to evaluate the efficacy of peri-interventional treatment with recombinant hirudin (r-hirudin [HBW 023]) compared with heparin in the prevention of troponin T release in patients with unstable angina.

BACKGROUND

Percutaneous transluminal coronary angioplasty in patients with unstable angina is associated with a high risk of acute thrombotic complications.

METHODS

Serial troponin T measurements were performed in 61 patients with unstable angina during the 48-h observation period after coronary angioplasty of the ischemia-related lesion. Patients were randomly assigned to peri-interventional intravenous treatment with either r-hirudin (dosage group I: 0.3-mg/kg body weight bolus, 0.12 mg/kg per h for 24 h; dosage group II: 0.5-mg/kg bolus, 0.24 mg/kg per h for 24 h) or heparin (150-IU/kg bolus, 20 IU/kg per h for 24 h). All patients received acetylsalicylic acid before coronary angiography. After 24 h, patients received a constant low dose infusion of either hirudin (0.04 mg/kg per h) or heparin (7 IU/kg per h) for another 24 h. The power of the study to detect a decrease in abnormal troponin T levels from 60% (heparin group) to 20% (combined r-hirudin groups) was 88%.

RESULTS

Serial troponin T measurements revealed two peaks within the 48 h after coronary angioplasty in the heparin but not the hirudin groups. An elevated serum troponin T concentration (> 0.2 ng/ml) within 48 h of coronary angioplasty was found in 9 (24%) of 38 patients in the hirudin groups (5 [25%] of 20 in dosage group I; 4 [22%] of 18 in dosage group II) compared with 11 (58%) of 19 in the heparin group (p = 0.01). We observed major cardiac events (death, myocardial infarction, abrupt vessel closure) in 1 (4.8%) of 21 patients in dosage group I, 1 (5.3%) of 19 in dosage group II and 3 (14.3%) of 21 in the heparin group (p = 0.33).

CONCLUSIONS

In this pilot trial, hirudin appears to be superior to heparin in preventing troponin T release after coronary angioplasty.