Reliability and discriminatory power of methods for dental plaque quantification

Objective

This in situ study evaluated the discriminatory power and reliability of methods of dental plaque quantification and the relationship between visual indices (VI) and fluorescence camera (FC) to detect plaque.

Material and Methods

Six volunteers used palatal appliances with six bovine enamel blocks presenting different stages of plaque accumulation. The presence of plaque with and without disclosing was assessed using VI. Images were obtained with FC and digital camera in both conditions. The area covered by plaque was assessed. Examinations were done by two independent examiners. Data were analyzed by Kruskal-Wallis and Kappa tests to compare different conditions of samples and to assess the inter-examiner reproducibility.

Results

Some methods presented adequate reproducibility. The Turesky index and the assessment of area covered by disclosed plaque in the FC images presented the highest discriminatory powers.

Conclusions

The Turesky index and images with FC with disclosing present good reliability and discriminatory power in quantifying dental plaque.     

Bacteriocin production by Shigella sonnei isolated from faeces of children with acute diarrhoea

Sousa MÂB, Mendes EN, Apolônio ACM, Farias LM, Magalhães PP. Bacteriocin production by Shigella sonnei isolated from faeces of children with acute diarrhoea. APMIS 2010; 118: 125–35. Shigella is a common agent of diarrhoea, a worldwide major health problem. The bacterium produces bacteriocins; however, the role of these substances as a virulence factor is completely unknown. With the aim to search for colicin production by Shigella sonnei, to evaluate the influence of culture conditions on bacteriocin expression, and to characterize the substance partially, 16 S. sonnei strains isolated from children with diarrhoea were tested for antagonism against members of the intestinal microbiota or agents of diarrhoea. Nine strains exhibited isoantagonism and heteroantagonism against S. flexneri and diarrhoeagenic Escherichia coli. Autoantagonism and antagonism against the intestinal microbiota were not detected. Culture medium and incubation conditions influenced antagonism expression. Antagonism resulting from bacteriophages, low pH, fatty acids, hydrogen peroxide, and chloroform was excluded. The activity of the intracellular fraction obtained with 75% ammonium sulphate was preserved at pH 1.0–11.0, and was found to be reduced by organic solvents and affected by high temperatures and proteases. The antagonistic spectrum and the in vitro conditions for better antagonism expression suggest that the role of colicin in S. sonnei virulence, if any, would be expressed prior to infection, and may regulate population density of enteropathogens by helping in organism transmission.     

Can the individual calibration be modified when laser fluorescence method is used for caries detection?

International Journal of Paediatric Dentistry 2013; 23: 138–144 Background. Individual calibration (IC) for caries detection methods based on fluorescence is time‐consuming, especially for paediatric dentists, if the calibration has to be performed tooth‐by‐tooth. However, it is not clear how this calibration actually interfere in laser fluorescence (LF) readings. Aim. This in vivo study was to verify the influence of different modes of IC on laser fluorescence (LF) readings. Design. Ninety six occlusal and 95 buccal surfaces of 1st permanent molars were examined using LF device after IC performed on control (no IC), the examined teeth, a permanent incisor, a 1st primary molar or a 2nd primary molar. All modes of IC were performed in the same child. Wilcoxon test and Bland–Altman analysis were used to compare the readings. Intraclass correlation coefficients (ICC) were calculated. Results. Laser fluorescence readings without prior calibration were higher than readings performed after any mode of IC and resulted in different values of ICC. After other IC modes, the LF readings were statistically similar. Conclusion. The absence of IC influences LF readings and LF reproducibility, but different IC methods can be considered in clinical practice.     

Physical and chemical properties of orthodontic brackets after 12 and 24 months: in situ study

Objective

The aim of this article was to assess how intraoral biodegradation influenced the surface characteristics and friction levels of metallic brackets used during 12 and 24 months of orthodontic treatment and also to compare the static friction generated in these brackets with four different methods of the ligation of orthodontic wires.

Material and Methods

Seventy premolar brackets as received from the manufacturer and 224 brackets that were used in previous orthodontic treatments were evaluated in this experiment. The surface morphology and the composition of the deposits found in the brackets were evaluated with rugosimetry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Friction was analyzed by applying tensile tests simulating sliding mechanics with a 0.019x0.025" steel wire. The static friction levels produced by the following ligation methods were evaluated: loosely attached steel ligature around all four bracket wings, steel ligature attached to only two wings, conventional elastomeric ligation around all 4 bracket wings, and non-conventional Slide^® elastomeric ligature.

Results

The results demonstrated the presence of biodegradation effects such as corrosion pits, plastic deformation, cracks, and material deposits. The main chemical elements found on these deposits were Carbon and Oxygen. The maximum friction produced by each ligation method changed according to the time of intraoral use. The steel ligature loosely attached to all four bracket wings produced the lowest friction levels in the new brackets. The conventional elastic ligatures generated the highest friction levels. The metallic brackets underwent significant degradation during orthodontic treatment, showing an increase in surface roughness and the deposit of chemical elements on the surface.

Conclusion

The levels of static friction decreased with use. The non-conventional elastic ligatures were the best alternative to reduce friction.     

Non-invasive ventilation improves peripheral oxygen saturation and reduces fatigability of quadriceps in patients with COPD

Background and objective:   Non-invasive ventilation (NIV) might improve peripheral muscle function and exercise capacity in severely disabled patients. This study evaluated the physiological impact of NIV on isokinetic concentric strength and endurance of lower limb muscles in patients with severe COPD.
Methods:   This clinical trial tested COPD patients ( n  = 24) and healthy subjects ( n  = 18). Subjects underwent isokinetic dynamometry tests while given either bi-level positive airway pressure ventilation (BV) or sham ventilation (SV), in a randomized order with 30 min of rest prior to each intervention. The inspiratory level of BV was set up to 14 cm H₂O and expiratory pressure up to 6 cm H₂O. Peripheral oxygen saturation (SpO₂), heart rate (HR), systolic (SBP) and diastolic blood pressure (DBP) at the peak of exercise were measured for each intervention.
Results:   Compared with controls, COPD patients had lower values of SpO₂ and HR ( P  < 0.01) during both BV and SV and lower values of DBP ( P  < 0.01) during BV. BV improved SpO₂ ( P  < 0.01), and reduced SBP in both COPD ( P  < 0.01) and control groups ( P  < 0.05) and reduced DBP in COPD patients ( P  < 0.01). BV also reduced the fatigue index in COPD patients when compared with SV ( P  = 0.003). Variation (BV-SV) of total work at the peak of the test was higher in the control group than in the COPD group ( P  < 0.05).
Conclusions:   BV improved SpO₂ and reduced the fatigability of the quadriceps muscle in patients with severe COPD. These results support the need for further evaluation of BV as adjunct during high-intensity strength exercise training in these patients.     

Temporary Atrial Pacing in the Prevention of Postoperative Atrial Fibrillation

Background: Atrial fibrillation (AF) is a common complication after coronary artery bypass grafting (CABG). Since its prevention with prophylactic drug therapy has limited success, alternative approaches are desirable. This study examined the efficacy of atrial or biatrial pacing, compared with no pacing, on the incidence of AF after isolated CABG.
Methods: From August 2002 to September 2004, 240 patients underwent CABG. After surgery, right and left atrial epicardial pacing wires were implanted for 72 hours of temporary pacing. Patients were randomly assigned to one of three groups: no pacing (control group), right atrial (RA), and biatrial (BiA) pacing. Cardiac rhythm was monitored continuously during intensive care, or daily on the ward. The primary endpoints of this study were an episode of AF occurring up to 72 hours after CABG and the risk factors correlated with this event.
Results: Atrial and BiA pacing significantly lowered the incidence (1.25% vs 25%, P = 0.001) of AF episodes, and were both correlated (odd ratio 0.038; 95% confidence interval 0.005–0.29) with a decrease in rates of postoperative AF. Multivariable analysis identified older age (odd ratio 1.074; 95% confidence interval 1.024–1.12) and no pacing as independent risk factors of postoperative AF.
Conclusions: Temporary right atrial or biatrial pacing after CABG significantly decreased the postoperative incidence of AF. Multivariable analysis identified older age and no pacing as predictors of AF occurrence .     

Assessment scale of the oral motor performance of children and adolescents with neurological damages

Summary  Among the conditions that classify individuals as special needs patients are those resulting from neurological sequelae, particularly cerebral palsy (CP), which is a disorder of high prevalence. Innumerable alterations can be found in individuals with CP but the inability to control striated muscles, due to damages suffered by the central nervous system, should be emphasized. Changes in tonus, speed and strength of oral muscles, reduction of mandibular mobility amplitude and difficulty to passively seal the lips are characteristics observed in such individuals. Categorization of the individual's mastication pattern is important in order to establish diagnosis and treatment protocols and prognosis. The aim of this study was to develop an Oral Motor Assessment Scale (OMAS) and evaluate its performance in terms of construct validity and reliability in a cohort of 53 children and individuals with CP. Two dentists examined the same patients on two different occasions. Good interexaminer (kappa > 0·85) and intra-examiner (kappa > 0·90) agreement was obtained for the majority of the OMAS items. This study shows that the OMAS is an accurate and valid method of assessment of oral motor skills in children and adolescents with neurological damages.