Polyelectrolyte film fabrication by successive spraying of polycation and polyanion solutions is described and compared to classic dipping. The poly(styrenesulfonate)/poly(allylamine) system is examined in detail. The influence of various parameters such as spraying time, polyelectrolyte concentration, and effect of film drying during multilayer construction is investigated. It is found that film deposition by spraying is easily controlled and very reliable. The thickness of the multilayers grows linearly with the number of deposition cycles similarly to what is observed when dipping substrates or when polyelectrolyte solutions flow over a surface. The assembly of films is very fast and leads to films with small surface roughness as estimated by atomic force microscopy and X-ray reflectometry. Spray deposition allows achieving regular multilayer growth even under conditions for which dipping fails to produce homogeneous films (e.g., extremely short contact times). Moreover, because drainage constantly removes a certain quantity of the excess material arriving at the surface, one can even skip the rinsing step and, thus, speed up even further the whole buildup process.

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In a previous paper (Michel, M.; Vautier, D.; Voegel, J.-C.; Schaaf, P.; Ball, V. Langmuir 2004, 20, 4835), we showed that phospholipid vesicles can be incorporated into poly(glutamic-acid)/poly(allylamine) (PGA/PAH) multilayered polyelectrolyte films built by the alternated dipping of a surface in polyanion and polycation solutions. AFM imaging, quartz crystal microbalance, and ellipsometry suggested that the vesicles remain intact when adhering on the surface. In the present paper, we show that such films can also be realized by spraying both the polyelectrolyte solutions and the vesicles onto the surface. Using such vesicles filled with ferrocyanide ions, we prove by cyclic voltammetry that the sprayed vesicles remain intact when embedded in the multilayers. We show that multilayers containing two distinct layers of intact vesicles separated by several polyanion/polycation bilayers can also be constructed. Polyelectrolyte multilayers containing layers of phospholipid vesicles could act as reservoirs for drug or other biologically active molecules in controlled release bioactive coatings.

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This investigation examined the effects of pharmacologically induced precocious puberty on cranial growth in Wistar rats. Forty-eight female newborn Wistar rats were divided into two groups: a control group (C) and an experimental group (E), with four subgroups of six animals each. The time interval from birth until sacrifice differed between the subgroups, and was set at 30, 60, 90, and 120 days. An intramuscular single dose (300 μg) of steroid hormone danazol was administered on day 5 after birth, as a means of inducing precocious puberty. Alizarin (2 mg/100 g) was administered to three animals in each subgroup three days prior to sacrifice. Body mass and dates corresponding to the beginning of the oestrous cycle were recorded. Craniometric measurements were undertaken. Histological analysis using light and fluorescence microscopy was then carried out to qualitatively and quantitatively evaluate the spheno-occipital synchondrosis and to visualize bone deposition patterns. The results were analysed with a Student's t-test and analysis of variance. Precocious puberty was effectively induced and differences between groups denoted an earlier maturation in the experimental rats. In qualitative analysis, a significant increase of total synchondrosis width was noted only in group E60, in comparison with C60, and an increase in the E90 subgroup cortical bone width compared with the C90 subgroup. Histomorphometrically, a statistical difference between total width values of subgroups E60 (434.3 μm) and C60 (323.5 μm) was detected. However, body mass and macroscopic measurements did not show statistically significant differences. An appropriate model for studying bone growth associated with precocious puberty in Wistar female rats was not achieved using steroid hormone danazol, when evaluated at 30 day intervals.

Aim: The aim of this systematic review was to compare the maxillary dental effects of cervical headgear and pendulum appliance during distalization of permanent maxillary first molars. Methods: A literature survey from databases covering the period from 1956 to August 2008 was carried out. Randomized controlled trials (RCT) and controlled clinical trials (CCT) were included. Two reviewers selected and extracted the data independently, and also assessed the quality of the retrieved studies. Results: The search strategy resulted in 48 articles, of which 3 met the inclusion criteria. Distal molar movement with headgear versus pendulum appliance was identified. In all studies selected, the methods used to detect and analyze the distal molar movement were valid and generally well know. All articles included an error analysis method and considered the risk for confounding factors, but only one study used blinding in measurements. Conclusions: The studies showed that both cervical headgear with patient compliance and a non-compliance pendulum appliance are very effective in distalizing maxillary molars. However, additional RCTs with larger samples of both molar distalizing appliances are needed to confirm this result and provide further reliable scientific evidence.

Varnish application is necessary to preserve the cement and avoid enamel decalcification. Glass-ionomer cements should be protected in order to fully keep their properties, thus contributing to dental health during orthodontic treatment.

Objective: Verify the in vitro effectiveness of different porcelain surface polishing systems used after orthodontic debonding. Materials and Methods: Restorations were simulated by 52 metallic samples covered with glazed feldspathic porcelain. Four of these intact samples composed the control group (C). The remaining samples were divided into four groups (n ϭ 12), according to the surface preparation they were to receive: no surface treatment (G1); roughened with a diamond bur (G2); etched with 10% hydrofluoric acid (G3); and sandblasted with aluminum oxide (G4). All experimental samples were treated with silane and bonded with a primer and standardized amount of adhesive. After composite removal, each group was divided into subgroups randomly (n ϭ 4), according to the porcelain polishing system used: Edenta (P1); Identoflex (P2); and Komet (P3). All 52 sample-surfaces were evaluated quantitatively with a profilometer, and a mean roughness profile (Ra) value was determined for each sample. Both control and experimental specimens were evaluated qualitatively using a scanning electron microscope (SEM) to assess surface morphology. Results: Statistical analysis with analysis of variance (ANOVA) and post-hoc Tukey multiple comparisons test showed statistical differences between surface preparation groups (G1 G2 ϭ G3 ϭ G4), at ␣ ϭ .05 level of significance; as for polishing protocols, no statistical difference was found. Conclusions: The surface preparation was the determinant for final surface texture. No combination between surface preparation and polishing system was able to reestablish the original glazed porcelain smoothness. (Angle Orthod. 2009;79:790-795.)