Performance Assessment of Colorimetric Devices on Dental Porcelains

The selection of an appropriate material that duplicates the appearance of natural tooth structure is very important in restorative dentistry. Photometric and colorimetric analysis techniques offer great potential as a tool for aiding in the duplication process. The degree to which these techniques will be useful depends on the accuracy and precision with which they can be applied to translucent as well as opaque surfaces. The purpose of this investigation was to evaluate the performance of three currently-available photometric devices. The performance capabilities of the instruments were tested on various shades of opaque and translucent dental porcelain surfaces. The performance tests were designed for evaluation of the accuracy and precision of the instrument relative to a well-studied reference instrument. CIELAB color difference metrics were used for the performance analysis. The results revealed that each of the photometric instruments evaluated was capable of producing color measurements with precision. However, the degree of accuracy with which the color measurements were made varied depending on the instrument used and the type of material surface being measured. A photo-electric tristimulus colorimeter showed the best overall performance on the porcelain surfaces, supporting its use as a valuable tool for evaluating color in dentistry.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68099/2/10.1177_00220345890680120701.pd

Three-body wear potential of dental yttrium-stabilized zirconia ceramic after grinding, polishing, and glazing treatments

Statement of problem. Zirconia complete-coverage crowns are being widely used as restorations because of their improved esthetic characteristics. Data about the enamel wear potential of this ceramic after chair side adjustments are sparse. Purpose. The purpose of this study was to investigate the 3-body wear of enamel opposing 3 types of ceramic (dense sintered yttrium-stabilized zirconia; Crystal Zirconia; DLMS) (Z), a lithium disilicate (IPS e-max CAD; Ivoclar Vivadent) (E), and a conventional low-fusing feldspathic porcelain (VitaVMK-Master; Vita Zahnfabrik) (P), treated to impart a rough, smooth, or glazed surface. Material and methods. Twenty-four specimens of each of the zirconia and the lithium disilicate ceramic were sectioned from computer-aided design and computer-aided manufacturing blocks into rectangular plates (15 12 2 mm). Twenty-four specimens of the feldspathic porcelain were formed into disks (12 mm diameter) from powders compressed in a silicone mold. All specimens (n¼72) were prepared according to the manufacturers’ recommendations. Specimens of each ceramic group were placed into 1 of 3 groups: group R, rough surface finish; group S, smooth surface finish; and group G, glazed surface finish. A total of 9 groups with 8 specimens each were placed in a 3-body wear simulator, with standardized enamel specimens (n¼72) acting as the substrate. The wear of the enamel specimens was evaluated after 50 000 cycles. The data were analyzed with 2-way ANOVA and the Tukey HSD multiple comparison test (a¼.05). Results. The data showed that the smooth zirconia group (ZS) was associated with the least amount of enamel wear (1.26 0.55 mm2). The most antagonistic enamel wear was associated with the glazed groups ZG (5.58 0.66 mm2), EG (3.29 1.29 mm2), and PG (4.2 1.27 mm2). Conclusions. The degree of enamel wear associated with monolithic zirconia was similar to conventional feldspathic porcelain. Smoothly polished ceramic surfaces resulted in less wear of antagonistic enamel than glazing

Non-Pharmacological Treatments

In clinical psychiatry, we dispose of different non-pharmacological approaches, such as somatic treatments, chronobiological treatments, cognitive remediation, and psychotherapy. Somatic treatments include transcranial direct current stimulation (tDCS), transcranial magnetic stimulation (TMS), and electroconvulsive therapy (ECT). These techniques, which exert their function through the modulation of cortical excitability, find an application in many psychiatric disorders, but mainly in resistant depression. Chronotherapies, a group of non-pharmacological therapeutic approaches to mood disorder treatment, are rooted in the hypothesis of chronobiology aetiopathogenesis of psychiatric disorders (mainly mood disorders). Chrono-biological treatments include light therapy (LT), sleep deprivation (SD), and dark therapy (DT). While LT and SD are mainly used in depression, DT finds a clinical application in mania. Cognitive remediation (CR) is a set of interventions based on behavioural training whose goal is to enhance neurocognitive abilities. This technique finds its main application in schizophrenia. Psychotherapy approaches have a proved effectiveness for the treatment of various psychiatric conditions when combined to psychopharmacological treatment. The two main approaches are cognitive-behavioural therapy and psychodynamic therapy

Nanoparticles for Local Drug Delivery to the Oral Mucosa: Proof of Principle Studies

Purpose To determine if solid lipid nanoparticles represent a viable strategy for local delivery of poorly water soluble and unstable chemopreventive compounds to human oral tissues. Methods Nanoparticle uptake and compound retention evaluations employed monolayer-cultured human oral squamous cell carcinoma (OSCC) cell lines and normal human oral mucosal explants. Feasibility of nanoparticle delivery was also evaluated with respect to the presence of phase-III efflux transporters in normal oral mucosal tissue and OSCC tissues. Results Functional uptake assays confirmed significantly greater internalization of nanoparticle-delivered fluorescent probe relative to free-fluorescent probe delivery, while concurrently demonstrating nanoparticle uptake rate differences among the OSCC cell lines and the phagocytic control human monocyte cell line. Mucosal explants exhibited nanoparticle penetration and internalization in the spinous and basal epithelial layer