Impression materials: effect of hydrophilicity and viscosity on ability to displace water from dentin surfaces

Abstract – The water-displacing ability of hydrophilic and hydrophobic impression materials was determined and related to the hydrophilicity and viscosity of the materials. The waterdisplacing ability of the materials was determined on a network of grooves in a dentin surface covered by a drop of water. After setting of the material, the number of crossings reproduced in the impression was calculated in percent of the total number of crossings. The hydrophilicity was assessed by measuring the contact angle between water and impression material. To determine viscosity, a rotoviscosimeter was used. Impression materials with contact angles less than 70° showed a significant negative correlation between water-displacing ability and contact angle, i.e. the reproducing ability decreased with decreasing hydrophilicity of the materials. Impression materials with contact angles above 70° showed a significant positive correlation between water-displacing ability and viscosity, i.e. the water-displacing ability improved with increasing viscosity.     

A RISK FACTOR APPROACH TO THE ALCOHOL-RELATED DISEASES

Alcohol-related disorders belong to the spectrum of major non-infectiousdiseases in Western societies which are capable of preventionby means that have not yet been fully implemented. The mortalityin a population of 10,353 middle-aged males invited to a preventivemedical population program in Malm was assessed for 1.5–6.5years (mean 4.5 years) after the time of invitation and analysedin relation to participation or non-participation. The characteristicsat entry of the 7948 males who participated in screening werecompared in order to evaluate risk factor patterns for the majorcategories of premature death during the follow-up period. Among the non-participants for screening the mortality ratewas twice as high, and the death rate due to alcohol-relateddiseases was five times higher than among the participants.There were no significant differences between participants andnon-participants in the other death causes. The autopsy ratewas high, at 87.8%. Even in the males participating in the screening, alcohol-relateddeaths constituted a major mortality category, comprising 55of 218 cases, whereas cancer comprised 61 and coronary heartdisease 50 of the premature deaths in this group. In these three main categories of male premature mortality,significant and distinctly differential risk factor patternswere found. Risk factors for coronary heart disease involvedsmoking, serum cholesterol, triglycerides and systolic bloodpressure, and for alcohol-related deaths involved gamma-glutamyltransferase,an alcoholism screening questionnaire and, inversely, serumcholesterol and serum creatinine. In both groups of diseases,these risk factors could be combined into a highly predictivemultiple logistic risk factor function. The discriminative powerof this instrument was higher for the alcohol-related deathsthan for the coronary heart disease deaths. Malignant and alcohol-related diseases constituted at leastequally prominent categories as the cardiovascular disordersamong the deaths that occurred within middle age in these cohorts.All of these conditions are potentially avoidable and are associatedwith significant and distinctive risk factor patterns. Riskfactors may be applied to the alcohol-related disorders as signalsfor preventive measures in analogy with tested methods for theregulation of blood pressure and serum lipids.     

Cryoballoon Pulmonary Vein Isolation with Real-Time Recordings from the Pulmonary Veins

Introduction: Cryoballoon (CB) ablation represents a novel technology for pulmonary vein isolation (PVI). We investigated feasibility and safety of CB-PVI, utilizing a novel spiral catheter (SC), thereby obtaining real-time PV potential registration.
Methods: Following double transseptal puncture, a Lasso catheter (Biosense Webster, Diamond Bar, CA, USA) and the 28 mm CB were positioned within the left atrium. A novel SC (Promap, ProRhythm Inc., Ronkonkoma, NY, USA) was inserted through the lumen of the CB allowing PV signal registration during treatment. Time to PV conduction block was analyzed. If no stable balloon position was obtained, the SC was exchanged for a regular guide wire and PV conduction was assessed after treatment by Lasso catheter.
Results: In 18 patients, 39 of 72 PVs (54%) were successfully isolated using the SC. The remaining 33 PVs were isolated switching to the regular guide wire. Time to PV conduction block was significantly shorter in PVs in which sustained PVI was achieved as compared to PVs in which PV conduction recovered within 30 minutes (33 ± 21 seconds vs 99 ± 65 seconds). In 40 PVs, time to PV conduction block was not obtained because of: (1) PVI not being achieved during initial treatment; (2) a distal position of the SC; or (3) isolation with regular guide wire. No procedural complications occurred.
Conclusion: Visualization of real-time PV conduction during CB PVI is safe, feasible, and allows accurate timing of PVI onset in a subset of PVs. Time to PV conduction block predicts sustained PVI. However, mechanical properties of the SC need to be improved to further simplify CB PVI.     

Caries risk profiles in schoolchildren over 2 years assessed by Cariogram

International Journal of Paediatric Dentistry 2010; 20: 341–346 Background. Caries risk assessment is an important tool in clinical decision making. Aim. To evaluate longitudinal changes in caries risk profiles in a group of schoolchildren in relation to caries development. Design. The Cariogram model was used to create caries risk profiles and to identify risk factors in 438 children being 10–11 years at baseline. The assessment was repeated after 2 years and the caries increment was recorded. The frequency of unfavourable risk factors were compared between those considered at the lowest and the highest risk. Results. Fifty percent of the children remained in the same risk category after 2 years. One third of the children were assessed in a higher‐risk category while 18.4% showed a lower risk. Those with increased risk compared with baseline developed significantly more caries than those with an unchanged risk category. The most frequent unfavourable risk factors among those with high risk at baseline were high‐salivary mutans streptococci and lactobacilli counts as well as frequent meals. Conclusion. Half of the children showed a changed risk category after 2 years, for better or for worse, which suggests that regular risk assessments are needed in order to make appropriate decisions on targeted preventive care and recall intervals.     

Carotid Revascularization: A Systematic Review of the Evidence

Objective and Background

The aim of this study is to provide an evidence‐based review of the periprocedural safety and long‐term effectiveness of carotid artery stenting (CAS) compared to carotid endarterectomy (CEA), with particular attention paid to the use of embolic protection devices and patients at high risk for CEA.

Methods

Electronic databases (Ovid Medline, Cochrane central register of controlled trials, Pubmed, and Embase) were searched to identify: (1) randomized controlled trials (RCT) comparing outcomes of CEA and CAS, and (2) prospective clinical trials assessing the safety of CAS in patients at high surgical risk. Pooled incidence rates and one‐sided 95% confidence interval for the periprocedural and long‐term composite end‐point of stroke, myocardial infarction, or death among high surgical risk patients were generated and compared to objective performance criteria (OPC) reported by previous trials.

Results

Six RCTs and 14 prospective clinical trials met our search criteria. Selected RCTs showed inconsistency in reported periprocedural and long‐term outcome rates. Pooled incidence rates of the periprocedural and long‐term composite end‐point of stroke, myocardial infarction or death in high surgical risk candidates were 5.59% and 7.92%, respectively. These results were noninferior to selected OPCs (P‐value <0.001).

Conclusions

CAS represents a safe and effective stroke prevention strategy in high surgical risk patients when compared with CEA. The inconsistent results from the RCTs and the improved outcomes in the prospective clinical trials are likely related to variability in operator experience, use of embolic protection devices, and patient selection strategies.

     

The Prevalence of Mutations in KCNQ1, KCNH2, and SCN5A in an Unselected National Cohort of Young Sudden Unexplained Death Cases

Introduction: Sudden unexplained death account for one‐third of all sudden natural deaths in the young (1–35 years). Hitherto, the prevalence of genopositive cases has primarily been based on deceased persons referred for postmortem genetic testing. These deaths potentially may represent the worst of cases, thus possibly overestimating the prevalence of potentially disease causing mutations in the 3 major long‐QT syndrome (LQTS) genes in the general population. We therefore wanted to investigate the prevalence of mutations in an unselected population of sudden unexplained deaths in a nationwide setting. Methods: DNA for genetic testing was available for 44 cases of sudden unexplained death in Denmark in the period 2000–2006 (equaling 33% of all cases of sudden unexplained death in the age group). KCNQ1, KCNH2, and SCN5A were sequenced and in vitro electrophysiological studies were performed on novel mutations. Results: In total, 5 of 44 cases (11%) carried a mutation in 1 of the 3 genes corresponding to 11% of all investigated cases (R190W KCNQ1, F29L KCNH2 (2 cases), P297S KCNH2 and P1177L SCN5A). P1177L SCN5A has not been reported before. In vitro electrophysiological studies of P1177L SCN5A revealed an increased sustained current suggesting a LQTS phenotype. Conclusion: In a nationwide setting, the genetic investigation of an unselected population of sudden unexplained death cases aged 1–35 years finds a lower than expected number of mutations compared to referred populations previously reported. We therefore conclude that the prevalence of mutations in the 3 major LQTS associated genes may not be as abundant as previously estimated. (J Cardiovasc Electrophysiol, Vol. 23 pp. 1092‐1098, October 2012)     

Anatomical differences in the psoas muscles in young black and white men

The anatomy of the psoas major muscle (PMA) in young black and white men was studied during routine autopsies. The forensic autopsies included 44 fresh male cadavers (21 black, 23 white) with an age span of 14 to 25 y. The range for weight was 66–76 kg and for height 169–182 cm. The PMA was initially measured in its entire length before measuring the diameter and circumference at each segmental level (L1–S1). At each segmental level, the calculated anatomical cross-sectional area (ACSA) was more than 3 times greater in the black group compared with the white ( P <0.001). The psoas minor muscle (PMI) was absent in 91% of the black subjects, but only in 13% of the white subjects. These data show that the PMA is markedly larger in black than white subjects. The marked race specific difference in the size of the PMA may have implications for hip flexor strength, spine function and race specific incidence in low back pathology, and warrants further investigation.     

Impairment severity selectively affects the control of proximal and distal components of reaching movements in children with hemiplegic cerebral palsy

This study explored proximal-to-distal components during goal-directed reaching movements in children with mild or moderate hemiplegic cerebral palsy (HCP); [seven females, four males; mean age 8y 6mo; SD 27mo], compared with age-matched, typically developing children (seven females, five males; mean age 8y 3mo [SD 25mo]. Severity of HCP was assessed following the approach of Claeys et al. Optoelectronic registrations were made during unimanual reaching-to-grasp and reaching-to-hit movements with both the affected/non-preferred and unaffected/preferred side. Regardless of task, the children with HCP, particularly those with moderate impairment, displayed less optimal spatiotemporal organization of movements performed with the affected arm. Compared with the goal to hit, and increasingly with more severe impairment, children with HCP adapted to the goal to grasp by recruiting augmented shoulder movements when reaching with the affected side. A resulting impact on distal kinematics was found in shorter, straighter, and less segmented movement paths. Thus, depending on severity of hemispheric lesions and task complexity, unilateral brain injuries in HCP may selectively affect neural pathways underlying both proximal and distal arm movement control. Levels of both ipsi- and contralateral activation in relation to side and lesion severity should be considered in future studies on prehension movements in HCP.     

Serum lipids and apolipoproteins A-I, A-II and B in primary hypothyroidism before and during treatment

Serum lipids and apolipoproteins (apo) A-I, A-II, and B were measured in twenty-four patients with severe primary hypothyroidism (Thyrotropin above 40 mU/l), before and during 1-thyroxine treatment. Apo A-I, A-II, and B were assayed by immunonephelometry, using monospecific antisera. The serum levels of total cholesterol (TC), of low-density lipoprotein cholesterol (LDLc), and of the major LDL apoprotein, apo B, were markedly increased in the untreated hypothyroid patients compared to the values during therapy (TC: mean +/- SD, 8.87 +/- 2.9 v. 5.48 +/- 1.6 mmol/l; LDLc: 6.66 +/- 2.6 v. 3.78 +/- 1.4 mmol/l; apo B: 1.66 +/- 0.48 v. 1.14 +/- 0.37 g/l; P less than 0.00001 for all variables). High-density lipoprotein cholesterol (HDLc) was slightly higher before than during therapy (1.58 +/- 0.7 v. 1.31 +/- 0.4 mmol/l; P less than 0.05), while the main HDL apoprotein, apo A-I, was significantly elevated (1.49 +/- 0.42 v. 1.13 +/- 0.27 g/l; P less than 0.0002). The increase of the second major HDL apoprotein, apo A-II, was less pronounced (0.33 +/- 0.1 v. 0.30 +/- 0.08 g/l; P less than 0.022). The apo A-I to apo A-II ratio, which reflects the relative concentrations of the HDL subfractions HDL2 and HDL3, was significantly higher before than during treatment (P less than 0.0006). Serum triglyceride levels were moderately elevated in the untreated hypothyroid patients (1.34 +/- 0.6 v. 0.95 +/- 0.4 mmol/l; P less than 0.002). The small decrease in body weight during therapy did not correlate with the changes of the various lipid and apoprotein parameters.(ABSTRACT TRUNCATED AT 250 WORDS)