Effects of buccal versus lingual surfaces, enamel conditioning procedures and storage duration on brackets debonding characteristics

OBJECTIVES: To determine the influence of two enamel conditioning techniques on buccal and lingual tooth surfaces at two different times on debonding strength and tooth damage. METHODS: The study included 50 premolars. Buccal and lingual surfaces of 10 teeth were scanned using SEM before (N=4) and after enamel conditioning by either acid etching or sandblasting prior to acid etching (N=6) for their morphology. The remaining 40 teeth were divided into 2 equal groups, differing in enamel conditioning prior to metallic bracket bonding on the buccal and lingual surfaces. Each group was equally subdivided into short-term (48h) or long-term (12m) water storage. Debonding strength was measured followed by SEM and EDAX for adhesive remnant index (ARI) and calcium remnant index (CRI) left on bracket bases. ANOVA with repeated measures was applied to the results. RESULTS: The buccal enamel was rougher than the lingual one. The surface morphology after the two types of conditioning showed a different pattern. A significantly higher debonding strength was needed to debond the buccal brackets compared to the lingual ones (p<0.05). A significantly higher ARI (p<0.002) and higher CRI (p<0.005) were found in the lingual surface compared with the buccal. No differences were found in debonding strength ARI or CRI regarding the different conditioning or storage duration. CONCLUSIONS: Lingual bonding leads to higher ARI and CRI than buccal bonding. Sandblasting prior to etching does not improve bonding strength for lingual or buccal bonding.     

Pulse transmission coefficient: a nonhyperemic index for physiologic assessment of procedural success following percutaneous coronary interventions.

Intracoronary pressure measurements and the determination of fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) predict adverse events. Coronary lesions may impair the transmission of pressure waves across a stenosis, potentially acting as a high-frequency filter. The pulse transmission coefficient (PTC) is a nonhyperemic parameter that calculates the transmission of high-frequency components of the pressure signal through a stenosis. It was shown recently that PTC is highly correlated with FFR. This study was designed to examine the change of PTC as compared to FFR following PCI. Pressure signals were obtained by pressure guidewire in 27 lesions pre- and post-PCI and were analyzed with an algorithm that identifies the high-frequency component in the pressure signal. The PTC was calculated at baseline as the ratio between distal and proximal high-frequency components of the pressure waveform across the lesion. FFR measurements were assessed with intracoronary adenosine. There was a significant increase in PTC following PCI (0.15 +/- 0.17 at baseline vs. 0.84 +/- 0.11 post-PCI; P < 0.001). Comparable changes were observed for FFR (0.58 +/- 0.12 at baseline vs. 0.91 +/- 0.05 post-PCI; P < 0.001). PTC is a nonhyperemic parameter for physiologic assessment of coronary artery stenoses. Similar to FFR, PTC is significantly increased following PCI. Thus, it may serve as an adjunct index for the functional assessment of procedural success following PCI.     

Catheter-based ultrasound thrombolysis--a new promising thrombus-debulking device for the treatment of intracoronary thrombosis.

Angiographic suggestion of intercoronary thrombus is often seen in patients sustaining acute coronary syndromes (ACS). Even in the era of stenting and glycoprotein IIb/IIIa antagonists, the presence of thrombus-rich lesion during percutaneous coronary interventions portends an increased risk of adverse events. It has been hypothesized that reduction of clot-burden prior to PCI may reduce complications and enhance efficacy. Experimental and clinical data have shown that catheter-based ultrasound thrombolysis is capable of inducing an efficacious and safe thrombus-debulking. This article reviews the collective experience with this promising device solution for the treatment of thrombotic lesions in the setting of ACS.     

The influence of dentin and/or metal surface treatment on the retention of cemented crowns in teeth with an increased taper.

OBJECTIVES: To evaluate the effect of dentin and/or metal surface treatments on retention of cast crowns cemented to preparations with compromised retention. METHODS: Cast crowns (n=105) were fabricated on extracted molars prepared to 40 degrees convergence and standard height. 60 teeth were randomly divided into: (A) cemented with zinc phosphate cement; (B-D) cemented with resin cement (Compolute, 3M) with either no surface treatment (B), dentin etched and bonded (EBS multi, 3M) (C), or dentin etched and bonded, and metal tribochemically treated (Co-Jet, 3M) (D); 45 teeth were randomly divided and crowns cemented with another resin cement (Rely-X Arc, 3M) with either no surface treatment (E), dentin etched and bonded (Single Bond, 3M) (F), or dentin etched and bonded and metal tribochemically treated (G). Teeth were stored in 100% humidity for 3 months and thermocycled 5000 cycles. Crowns were dislodged from the preparations and retention (MPa) was calculated. RESULTS: Group D showed significantly higher retention (3.52+/-1.3 MPa) compared to Group C (2.26+/-0.9 MPa), Group B (0.85+/-0.4 MPa), and Group A (1.22+/-0.4 MPa). Group G exhibited significantly higher retention (5.4+/-1.4 MPa) compared to F (2.6+/-1.2 MPa) and E (2.0+/-0.6 MPa). Higher retention corresponded with more cohesive cement type of failure. SIGNIFICANCE: Cast crowns with compromised retention cemented by resin cement should undergo combined tribochemical metal treatment and dentin bonding. The crucial link is the interaction of different brands of resin cements with the metal tribochemically treated.     

Effect of Different Surface Treatments of Lithium Disilicate on the Adhesive Properties of Resin Cements

The aim of the current study was to evaluate the influence of hydrofluoric (HF) acid concentration and conditioning time on the shear bond strength (SBS) of dual cure resin cement to pressed lithium disilicate ceramic compared to treatment with an Etch and Prime self-etching glass-ceramic primer (EP). A total of 100 samples of pressed lithium disilicate (IPS e.max Press, Ivoclar Vivadent) were randomly divided into five groups (n = 20) according to surface treatment: two different concentrations of HF (5% or 9%), for different durations (20 or 90 s), or treatment with EP. Adhesion of light-cured resin cement to the treated surface was tested by the SBS test. The substrate surfaces of the specimen after failures were examined by SEM. Data were analyzed using Weibull distribution. The highest cumulative failure probability of 63.2% of the shear bond strength (η parameter) values was in the 9% HF −90 s group (17.71 MPa), while the lowest values were observed in the 5% HF −20 s group (7.94 MPa). SBS values were not affected significantly by the conditioning time (20 s or 90 s). However, compared to treatment with 5% HF, surface treatment with 9% HF showed a significantly higher η (MPa) as well as β (reliability parameter). Moreover, while compared to 9% HF for 20 s, EP treatment did not differ significantly in SBS values. Examination of the failure mode revealed a mixed mode of failure in all the groups. Within the limits of this study, it is possible to assume that IPS e.max Press surface treatment with 9% HF acid for only 20 s will provide a better bonding strength with resin cement than using 5% HF acid.     

Treatment of Induced Murine SLE with a Peptide Based on the CDR3 of an Anti-DNA Antibody Reverses the Pattern of Pathogenic Cytokines

A peptide based on the complementarity determining region (CDR) 3 of a pathogenic anti-DNA monoclonal antibody that bears the 16/6 idiotype (Id) was shown previously to be a dominant T-cell epitope in experimental SLE, and to be capable of inhibiting SLE-associated responses. When injected, concomitant with active immunization with the pathogenic human anti-DNA, 16/6 Id + mAb, pCDR3 inhibited the proliferation of LN-derived T cells stimulated in vitro with the 16/6 Id mAb. The inhibition of the specific proliferative responses could be reversed by the addition of exogenous IL-2 to the cultures. Analysis of secreted cytokine profile in supernatants of these cultures demonstrated that pCDR3 treatment reduced significantly the levels of both IL-2 and IFN- &#110 that were elevated further in cells of the 16/6 Id-immunized mice. The CDR3-based peptide was shown here to immunomodulate in vivo experimental SLE, induced by the human anti-DNA 16/6 Id + antibody. The beneficial effects of pCDR3 on the clinical manifestations of SLE were associated with downregulation of the Th1-type (IL-2, IFN- &#110 ) and proinflammatory (TNF- &#102 ) cytokines, whereas the immunosuppressive cytokine TGF- &#103 was up regulated.     

Effect of enalapril and nifedipine on orthostatic hypotension in older hypertensive patients

OBJECTIVE: To compare the effect of enalapril with long-acting nifedipine on orthostatic hypotension in older patients. DESIGN: A prospective, double blinded, cross-over study. SETTING: The outpatient clinic of a university hospital. PARTICIPANTS: Thirty-nine patients aged 65 years or older with systolic blood pressure (SBP) of 140-190 mm Hg and diastolic blood pressure (DBP) of 90-110 mm Hg. INTERVENTION: Enalapril 5-20 mg od or nifedipine 30-90 mg od for 8 weeks, followed by 4 weeks washout and cross-over for a second 8-week period. MEASUREMENTS: Supine and standing 0-, 1-, and 5-minutes blood pressure was recorded before and at the end of each treatment period. RESULTS: At baseline, SBP was 158.8 +/- 8.7 mm Hg, and DBP was 97.1 +/- 5.9 mm Hg. There was a decline in SBP of 6.1 +/- 2.7 mm Hg and 8.4 +/- 4.1 mm Hg after 1 and 5 minutes of standing, respectively. Both agents caused a significant decline in supine blood pressure. Enalapril: supine SBP 158.8 +/- 8.7 to 143 +/- 7.3 mm Hg; supine DBP 97.1 +/- 5.9 to 85.1 +/- 5.1 mm Hg (P = .0001). The drop in SBP after standing for 5 minutes was only 2.4 +/- 1.6 mm Hg with no change in diastolic values. A > or = 10 mm Hg drop in SBP was observed in only three patients, and no patient experienced a decline of 20 mm Hg or more. Nifedipine: supine SBP: 160.3 +/- 9 to 145.3 +/- 8.1 mm Hg; supine DBP: 96.3 +/- 5.7 to 86.3 +/- 5.8 (P = .0001). Nifedipine induced an orthostatic decline in SBP values; there was an 8.7 +/- 4.8 mm Hg difference between supine and 5 minutes standing values (P = .0005) without change in diastolic values. An orthostatic decline in SBP of > or = 10 mm Hg occurred in 13 patients, and there was a drop of > or = 20 mm Hg in six patients. The cross-over of enalapril and nifedipine reproduced the hypotensive effect and reversed the postural effect. (P = .0002 nifedipine vs enalapril) CONCLUSIONS: Enalapril and nifedipine were equipotent in reducing supine blood pressure levels. Enalapril also reduced the number of orthostatic episodes significantly, whereas nifedipine aggravated this phenomenon.     

Effect of clopidogrel pretreatment on angiographic and clinical outcomes in patients undergoing primary percutaneous coronary intervention for ST-elevation acute myocardial infarction

Pretreatment with clopidogrel before elective primary percutaneous coronary intervention (PCI) has been shown to reduce ischemic complications. There are limited data about the value of clopidogrel pretreatment in the setting of PCI for ST-elevation myocardial infarction (STEMI). We aimed to examine the effect of clopidogrel preloading on angiographic and clinical outcomes in patients with STEMI who were treated with PCI. We conducted a prospective registry of all patients treated with primary PCI for STEMI from March 2003 to June 2006. Excluded were patients with cardiogenic shock. For the current analysis, patients (n = 292) were allocated into 2 groups. One group received clopidogrel loading dose before PCI (in the emergency department or coronary care unit, n = 165); the other,immediately after PCI (n = 127). TIMI myocardial perfusion (TMP) grade at the end of PCI and 30-day and 6-month clinical outcomes were assessed. Clinical characteristics were similar among the groups. However, patients pretreated with clopidogrel were more likely to receive aspirin and beta blockers before the current admission. TMP grade 3 occurred in a higher proportion of patients in the clopidogrel pretreatment group than in the no-pretreatment group (85% vs 71%, p = 0.01). Multivariate logistic regression analysis showed that clopidogrel pretreatment was associated with an odds ratio of 2.2 for TMP grade 3 (1.2 to 3.9, p = 0.01). Furthermore, the incidence of reinfarction at 30 days was lower in the pretreatment group (0% vs 3.2%, respectively, p = 0.04). In conclusion, these findings support the early use of clopidogrel in patients with STEMI who are treated with primary PCI.