In vitro evaluation of abrasion of eroded enamel by different manual, power and sonic toothbrushes

This study aimed to evaluate the susceptibility of eroded enamel to brushing abrasion performed by manual, power or sonic toothbrushes. Bovine enamel samples were subjected to 5 cycles, each consisting of 5 min demineralisation, 15 min remineralisation and 10 min brushing in a machine. Toothbrushing with the activated electric devices was supplemented with 20 linear strokes/min. Furthermore, enamel specimens were brushed with 20 linear strokes/min or 80 linear strokes/min with the electric toothbrushes without their individual operating action. A manual brush was applied at 100, 20 or 80 linear strokes/min. Specimens of the control group were not brushed after demineralisation. Loss of enamel was determined by profilometry. For all groups, substrate loss for linear brushing treatment applying 20 or 80 strokes/min did not differ significantly from the control (4.97 +/- 1.49 microm). Three power toothbrushing treatments significantly increased abrasion compared to linear brushing treatment with 20 or 80 strokes/min in their inactivated condition. The results indicate that brushing treatment with power or sonic toothbrushes may lead to significantly higher loss of demineralised enamel compared to toothbrushing without power or sonic support.     

Effect of a casein/calcium phosphate-containing tooth cream and fluoride on enamel erosion in vitro

The aim of this study was to determine whether a tooth cream containing casein/calcium phosphate (CasCP) protects enamel against erosion. Sixty bovine enamel specimens were prepared for profilometry and distributed into five groups. Specimens were rinsed with artificial saliva interrupted by 1% citric acid (pH 2.3) for 30 s 6 times daily for 14 days. Group 1 (n=12) was not treated (control); in group 2 (n=12) CasCP was applied for 120 s twice daily; in group 3 (n=12) 250 ppm fluoride as NaF was applied for 120 s twice daily; in group 4 (n=12) CasCP was applied for 120 s, then 250 ppm fluoride for 120 s twice daily, and in group 5 (n=12) amine fluoride (AmF) gel (12,500 ppm fluoride) was applied for 120 s twice daily. Differences between groups with respect to erosive enamel loss (profilometrically determined depth after 7 and 14 days) were tested by the Mann-Whitney test (alpha=0.05). After 7/14 days' erosive cycling, specimens treated with AmF gel showed significantly less enamel loss (18.5/35.5 microm; medians) than those treated with CasCP (25.5/46.9 microm), 250 ppm fluoride (25.0/ 40.9 microm), CasCP and 250 ppm fluoride (23.9/47.4 microm) or with no treatment (26.3/49.8 microm). It is concluded that highly fluoridated acidic AmF gel can protect enamel against erosion while CasCP, 250 ppm fluoride or a combination of CasCP and 250 ppm fluoride provide little protection.     

Efficiency of 4 caries excavation methods compared

This in vitro study compared the efficiency (time taken to excavate and successfully remove bacterially infected dentin) of Fluorescence Aided Caries Excavation (FACE), caries detector dye (CD), chemomechanical excavation (CS) and conventional excavation (CE). Teeth with dentin caries were assigned to 4 groups (n= 25). Caries excavation was carried out by one operator. In the FACE group, the operating field was illuminated with violet light. The operator observed the teeth through a high-pass filter and removed orange-red fluorescing areas with a slow speed bur. In the CS group, Carisolv was applied to the cavity using CS hand instruments and allowed to act for 30 seconds before caries was removed. In the CD group, caries was removed using the Caries Detector and, in the CE group, conventional excavation was carried out using visual-tactile criteria. The excavation time was recorded. Undecalcified thin slices (8 microm) were prepared, stained with giemsa and examined using light microscopy. The excavation time (median) was significantly shorter for FACE (3 minutes, 3 seconds) compared to CS (5 minutes, 8 seconds, p=0.015), CD (5 minutes, 26 seconds, p=0.003) and CE (4 minutes, 2 seconds, p=0.025). Histology showed remaining bacteria in significantly fewer (5/25) FACE samples compared to CS (15/25 p=0.004) CD (12/25 p=0.037) but not significantly fewer than CE (11/25 p=0.069). In conclusion: the excavation result with FACE is equal to CE and superior to CD and CS but requires a significantly shorter excavation time.     

Volumetry of human molars with flat panel-based volume CT in vitro

The flat panel-based volume computed tomography (fpVCT) is a new CT device applicable for experimental, three-dimensional evaluation of teeth at a resolution of about 150 μm in the high contrast region. The aim of this study was to investigate whether fpVCT was suitable for quantification of the volumes of dental hard tissues and the root canal system to establish a new method for morphological studies. Fifty-two extracted third molars (maxillary: 31, mandibular: 21) were examined with a prototype of an fpVCT using a volumetry algorithm at different levels according to the radiographic density of enamel and dentine. Volumetry of the root canal system was performed after “region growing segmentation”: starting from a voxel in the centre of the root canal, this algorithm searches voxels of same density in the surrounding. The volumetry of the root canal system was stopped by the investigator at the apical constriction. Results showed that dentine, enamel and root canal system could be well distinguished in three-dimensional images. Volumetry yielded the following data (cm³, mean±SD): dentine 0.438±0.111, enamel 0.227±0.051, root canal system 0.052±0.017 and total volume 0.753±0.159. In conclusion, the fpVCT is appropriate for non-destructive volumetry of large numbers of teeth in experimental laboratory studies.     

Antimicrobial effectiveness of a highly concentrated chlorhexidine varnish treatment in teenagers with fixed orthodontic appliances

OBJECTIVE: To evaluate the recolonization pattern of Mutans streptococci (ms) on densely colonized teeth with fixed orthodontic appliances after treatment with a highly concentrated (36%) chlorhexidine varnish. MATERIALS AND METHODS: Healthy subjects (n = 19) with fixed orthodontic appliances and high bacterial ms counts in saliva were recruited. In order to establish a baseline registration, plaque adjacent to brackets was sampled and cultivated on Dentocult strips. Following professional tooth cleaning, chlorhexidine varnish was applied on all teeth for 8 minutes. The degree of recolonization with ms was assessed 2 weeks after varnish application in plaque around the brackets. For statistical analysis, the data were subjected to a repeated measures design. RESULTS: After 2 weeks, ms counts were reduced as compared to baseline values. However, the reduction only weakly met statistical significance (P = .049). CONCLUSIONS: The application of a highly concentrated chlorhexidine varnish in patients with fixed orthodontic appliances does not result in a distinct reduction of ms numbers 2 weeks after treatment.     

Is HOMA index a predictor of nocturnal nondipping in hypertensives with newly diagnosed type 2 diabetes mellitus?

OBJECTIVE: Insulin resistance is involved in glucose intolerance, type 2 diabetes mellitus and hypertension. We aimed to analyze relationship between insulin resistance and nocturnal nondipping. METHODS: Patients underwent physical and biochemical evaluation, clinic and ambulatory blood pressure measurements. The homeostasis model assessment (HOMA) index was calculated. RESULTS: Ninety-six essential hypertensive patients, of whom 42 were dippers, with newly diagnosed type 2 diabetes mellitus were included. Nighttime average heart rate and mean arterial pressure of nondippers were higher than dippers (P<0.0001 and 0.001). Nondippers had higher fasting plasma glucose, serum insulin levels and HOMA indices than dipper patients (P=0.006, <0.0001 and <0.0001). Ten dippers and 36 nondippers were insulin resistant (P<0.0001). Clinic (r=+0.22, P=0.031), daytime average (r=+0.27, P=0.007), nighttime average (r=+0.33, P=0.001), 24-h average systolic (r=+0.25, P=0.015) and nighttime average diastolic blood pressures (r=+0.31, P=0.002) were positively correlated with homeostasis model assessment index. Nighttime mean arterial pressure and heart rates (daytime, nighttime, 24-h average) showed positive correlation with homeostasis model assessment index. In multivariate analysis, high homeostasis model assessment index was associated with increased nondipping risk (odds ratio: 1.85, confidence interval: 1.24-2.76, P=0.003). After adjustment of several factors, average nighttime systolic (P<0.0001), diastolic (P<0.0001) and 24-h diastolic blood pressure (P=0.029) and heart rate (P=0.001) measurements of insulin resistant patients were higher than nonresistant patients. CONCLUSIONS: Insulin resistance is related with diurnal blood pressure variation. The HOMA index may be a predictor of nocturnal nondipping in patients with essential hypertension and newly diagnosed type 2 diabetes mellitus.     

Management of patients with nonvariceal upper gastrointestinal hemorrhage before and after the adoption of the Rockall score, in the Italian Gastroenterology Units

OBJECTIVES: Nonvariceal upper gastrointestinal hemorrhage is a frequent reason for ordinary hospital admission. In Italy the use of prognostic scores to stratify the risk has not been adequately validated: the impact on clinical management of a rating system like the Rockall score remains to be established. RING is a 'register' that has been collecting hospital discharge files from hospital gastroenterology units, giving a broad picture of the patients admitted for this pathology. METHODS: We analyzed the hospital discharge files collected between 2001 and 2005 from 12 gastroenterology units, which issued more than 26,000 hospital discharge files for ordinary hospital admission and have been using the Rockall score for defining nonvariceal upper gastrointestinal hemorrhage since 2003. RESULTS: There were 2832 hospital discharge files with a main diagnosis of nonvariceal upper gastrointestinal hemorrhage: 1335 'before' the Rockall score was introduced, 1497 'after' the introduction. Patients' mean age was 67.7+/-16.7 years, with a male/female ratio of 1.7 and no significant changes over the years. There were no differences in the distribution of diagnoses in nonvariceal upper gastrointestinal hemorrhage patients before/after the introduction of the Rockall score, though the mean hospital stay became shorter (7.1+/-5.0 vs. 6.3+/-4.5 days), and mortality declined (2.8 vs. 2.3%), in parallel with the caselist as a whole. For 1102 ordinary hospital admission Rockall score was calculated. Diagnoses were more accurate: significantly fewer undefined causes and an increase in peptic ulcer. The mean Rockall score was 4.6+/-2.2: 17.8% low (0-2), 48.7% intermediate (3-5), and 33.5% high (>or=6). Mean hospital stay, rebleeding, and mortality were correlated with the severity of the score. CONCLUSION: The Rockall score enables the clinician to formulate a more precise diagnosis and substantially shortens the time in hospital, especially for patients at low-risk of rebleeding and death, so more resources can be dedicated to critically ill patients.     

Safety of a thermal vessel sealer on main pulmonary vessels.

OBJECTIVE: LigaSure (Valleylab, Tyco Healthcare, Boulder, CO) is a novel instrument with widespread use in various surgical disciplines for vessel sealing. It uses heat energy to denature collagen and elastin and achieve vessel sealing. We investigated the safety of LigaSure in pulmonary arteries (PA) and veins (PV). METHODS: Twelve sheep were anesthetized and endotracheally intubated. Six underwent right lower lobectomy (Group 1) and six right upper lobectomy (Group 2). All of the vessels in both groups were divided with LigaSure. Diameters of vessels were measured. Intraoperatively, pulmonary artery pressures (PAP) were monitored in Group 1. Following vascular division, ephedrine was injected to increase PAP in Group 1. In Group 2, animals were followed and euthanized at 7 days. Both immediate and 7 day samples were obtained from divided vessel stumps. Conventional histology was done. Statistical analysis was performed using t-test and Fisher's exact test. RESULTS: Mean diameter of PAs (n=9) divided in Group 1 was 8.3mm (3-11) and of PVs (n=8) was 10.4mm (4-15). Mean PAP increased from 18 (27/9) to 27 (45/18)mmHg after ephedrine injection. Dehiscence rate was 2/6 in PAs and 3/6 in PVs larger than 9 mm in diameter. Mean diameter of PAs (n=8) divided in Group 2 was 5.7 mm (3-7) and of PVs (n=9) was 4.6mm (4-6). No early or late (7 days) vascular disruption was seen in Group 2. Bleeding incidence was significantly different between groups (Fisher's exact test p=0.015). Overall no dehiscence was observed in vessels less than 7 mm in diameter. Histology of intraoperative samples showed thermal injury and necrosis. Seven day samples showed short segment necrosis limited to the vessel wall, fibrosis, thrombus formation without inflammation, and minimal granulation tissue. CONCLUSIONS: LigaSure achieves perfect sealing in pulmonary vessels less than 7 mm in diameter in sheep intra- and postoperatively even following a pressure challenge. It can safely be used in segmental branches of PAs and PVs during open or thoracoscopic surgery.     

Left ventricular mechanics in isolated mild mitral stenosis: a three dimensional speckle tracking study

In a fraction of patients with mild mitral stenosis, left ventricular systolic function deteriorates despite the lack of hemodynamic load imposed by the dysfunctioning valve. Neither the predisposing factors nor the earlier changes in left ventricular contractility were understood adequately. In the present study we aimed to evaluate left ventricular mechanics using three-dimensional (3D) speckle tracking echocardiography. A total of 31 patients with mild rheumatic mitral stenosis and 27 healthy controls were enrolled to the study. All subjects included to the study underwent echocardiographic examination to collect data for two- and three-dimensional speckle-tracking based stain, twist angle and torsion measurements. Data was analyzed offline with a echocardiographic data analysis software. Patients with rheumatic mild MS had lower global longitudinal (p?<?0.001) circumferential (p?=?0.02) and radial (p?<?0.01) strain compared to controls, despite ejection fraction was similar for both groups [(p?=?0.45) for three dimensional and (p?=?0.37) for two dimensional measurement]. While the twist angle was not significantly different between groups (p?=?0.11), left ventricular torsion was significantly higher in mitral stenosis group (p?=?0.03). All strain values had a weak but significant positive correlation with mitral valve area measured with planimetry. Subclinical left ventricular systolic dysfunction develops at an early stage in rheumatic mitral stenosis. Further work is needed to elucidate patients at risk for developing overt systolic dysfunction.