Minimal alterations on the enamel surface by micro-abrasion: in vitro roughness and wear assessments

Objective:

To evaluate the in vitro changes on the enamel surface after a micro-abrasion treatment promoted by different products.

Material and Methods:

Fifty (50) fragments of bovine enamel (15 mm x 5 mm) were randomly assigned to five groups (n=10) according to the product utilized: G1 (control)= silicone polisher (TDV), G2= 37% phosphoric acid (3M/ESPE) + pumice stone (SS White), G3= Micropol (DMC Equipment), G4= Opalustre (Ultradent) and G5= Whiteness RM (FGM Dental Products). Roughness and wear were the responsible variables used to analyze these surfaces in four stages: baseline, 60 s and 120 s after the micro-abrasion and after polishing, using a Hommel Tester T1000 device. After the tests, a normal distribution of data was verified, with repeated ANOVA analyses (p≤0.05) which were used to compare each product in different stages. One-way ANOVA and Tukey tests were applied for individual comparisons between the products in each stage (p≤0.05).

Results:

Means and standard deviations of roughness and wear (mm) after all the promoted stages were: G1=7.26(1.81)/13.16(2.67), G2=2.02(0.62)/37.44(3.33), G3=1.81(0.91)/34.93(6.92), G4=1.92(0.29)/38.42(0.65) and G5=1.98(0.53)/33.45(2.66). At 60 seconds, all products tended to produce less surface roughness with a variable gradual decrease over time. After polishing, there were no statistically significant differences between the groups, except for G1. Independent of the product utilized, the enamel wear occurred after the micro-abrasion.

Conclusions:

In this in vitro study, enamel micro-abrasion presented itself as a conservative approach, regardless of the type of the paste compound utilized. These products promoted minor roughness alterations and minimal wear. The use of phosphoric acid and pumice stone showed similar results to commercial products for the micro-abrasion with regard to the surface roughness and wear.     

Secretory immune response in patients with intestinal amoebiasis

The secretory immune response in saliva from intestinal amoebiasis patients against antigens obtained from Entamoeba histolytica membranes was studied. Western blot analysis indicated that patient saliva contains secretory IgA antibodies against antigens with molecular masses ranging from 170 to 24 kDa, some of which were also recognized by saliva from healthy subjects. However, antigens of 170, 125, 46 and 37 kDa are recognized more frequently (> 90%) by the secretory IgA from patients with intestinal amoebiasis than by that from healthy subjects (< 10%).     

Bifocal Right Ventricular Resynchronization for the Failing Right Ventricle

The present case illustrates that in patients with right ventricular (RV) failure and right bundle branch block it is possible to resynchronize the RV without further worsening RV or left ventricular (LV) pump function, even in cases with various degrees of atrioventricular block. The acute response to different pacing configurations was analyzed in terms of dP/dt variations. Bifocal RV pacing (His bundle plus RV outflow tract pacing) achieved the best acute results and was chosen for permanent pacing. This pacing configuration was associated to clinical and echocardiographic improvement. (PACE 2011; 34:e78–e81)     

Decreased spontaneous arousability in preterm newborns with impaired neurological outcome

Preterm newborns are at high risk of neurological injury. In this population, we investigated the link between neurological complications and sleep architecture. At term‐corrected gestational age, we studied retrospectively the polysomnography of 45 preterm infants born at < 28 weeks or weighting < 1 kg. These infants were followed‐up by a neuropaediatrician (median age at last follow‐up 50.4 months). Two groups of children were constituted: a group without neurological disorder and a second group with at least one of the following: cerebral palsy, language or mental retardation, visual or hearing disability or attention disorder. A Multiple Indicators and Multiple Causes model assessed the relationship between the neurological outcome and two sleep components: spontaneous arousability [number of awakenings and movements per hour of quiet sleep (QS) and active sleep] and QS characteristics (median duration of QS cycles and percentage of QS over total sleep time). Twenty‐six infants had an impaired neurological outcome. There were no statistical differences between the two groups regarding clinical characteristics. Compared to preterm neonates with normal neurological outcome, those with impaired outcomes had a lower spontaneous arousability; i.e. 0.7 (0.5–1) times less awakenings and movements per hour of QS and 0.9 (0.8–1) times less per hour of active sleep than infants with normal outcomes (P = 0.05). The differences in QS characteristics did not reach statistical significance. These findings suggested that, in preterm infants, perinatal neurological injuries could be associated with an abnormal sleep architecture characterized by altered spontaneous arousability.