Evaluation of the staining potential of a caries infiltrant in comparison to other products.

In this study, we evaluated in vitro the staining susceptibility of an infiltration resin (Icon, DMG, Hamburg, Germany) and compared it with several marketed bonding systems. Fifty 1-mm-thick disk-shaped specimens were prepared for Icon and for each bonding material. Initial specimen color was assessed by a spectrophotometer. Specimens in each group were then randomly divided into five sub-groups and stored in an incubator at 37˚C in the dark for 60 days. Groups 4 and 5 were used as negative controls by being stored dry and in tap water respectively. Test groups were stored in (1) coffee, (2) tea, or (3) red wine. After 60 days of storage, new spectrophotometric measurements were performed and dE (color difference) was calculated to determine color change. Icon showed higher staining susceptibility. The clinician should be aware of the staining potential of infiltration resins over time.

A new classification of resin-based aesthetic adhesive materials.

The purpose of this article is to illustrate a new classification of resin based aesthetic materials laying on the characterization of their matrix and their filler morphology. Four samples per material have been prepared for SEM evaluation. Each sample has been treated with chloroform to dissolve its matrix in order to evidence the filler morphology. A general schema of four different matrix systems which characterize the material's level of hydrophobicity can be put in evidence. The subsequent filler analysis individuates a more complex schema based on filler size and construction. A new classification based on matrix nature and filler morphology has been proposed. Based on this concept mechanical and aesthetic characteristics of the materials can be presumed.

In vitro colorimetric evaluation of the efficacy of home bleaching and over-the-counter bleaching products.

OBJECTIVE: Various bleaching modalities are now offered to patients, either monitored by the dental office or self-directed, for which relative efficiency is unknown. The aim of this in vitro study was to evaluate the ability of bleaching products and protocols to lighten enamel and dentin. METHOD AND MATERIALS: Bovine tooth specimens of standardized thickness (2.5 +/- 0.025 mm with similar dentin and enamel thickness) were prepared and stained with whole blood and hemolysate before being submitted to seven supervised or self-directed bleaching regimens: tray-based bleaching using 10% (Opalescence, Ultradent; Nite White, Discus Dental) or light-activated 30% (Metatray, Metatray) carbamide peroxide (CP); 6% (Zoom, Discus Dental) or 9% (TresWhite, Ultradent) hydrogen peroxide (HP); strips (Whitening Strips, Oral B-Rembrandt); and paint-on gel (Paint on Plus, Ivoclar Vivadent) containing 8.1% and 6% HP, respectively. Colorimetric measurements were performed on each specimen side, according to the CIE L*a*b* system, before and after staining, as well as after 5, 10, and the recommended number of bleaching applications. RESULTS: Color change after recommended number of applications (DEr) varied from 15.72 (Metatray) to 29.67 (Nite White) at enamel and 14.91 (Paint on Plus) to 41.43 (Nite White) at dentin side; Nite White (10% CP) and TresWhite (9% HP) were more effective than Metatray (30% CP) and Paint on Plus (6% HP) after 5 or the recommended number of applications. CONCLUSION: In this in vitro study based on bovine teeth, tray-based systems produced the faster and better bleaching effect, regardless of the product and concentration used, at both enamel and dentin sides.

Pilot in vivo image spectro-photometric evaluation of optical properties of pure enamel and enamel-dentin complex.

OBJECTIVES: The aim of this in vivo study is to investigate the L*a*b*and the opacity (CR) of front teeth by means of an image spectrophotometer and to evaluate the eventual influence of the background color on the results. The second aim is to investigate if there is a relationship between tea, coffee, red wine drinking habits or smoking habits of the test subjects and tooth color. METHODS: A novel image based spectro-photometric approach was developed and applied on a Swiss Army recruits group quantifying L*a*b* of pure enamel as well as of enamel-dentin complex against black and white background together with CR. RESULTS: When 2mm thick pure enamel was considered, the values obtained were (mean (SD)) L*(76.3 (3.4)), a*(3.4 (1.2)) and b*(17.2 (2.45)) against white background and L*(63.5 (4.2)), a*(0.8 (1.3)) and b*(10.7 (2.7)) against black background. The opacity (CR) of 2mm thick pure enamel was (64.4 (0.1)). When 3mm thick enamel-dentin complex was considered, the values obtained were L*(79.0 (2.6)), a*(3.9 (1.3)) and b*(20.4 (3.0)) against a white background and L*(74.9 (3.0)), a*(1.8 (1.2)) and b*(16.7 (3.1)) against a black background. The opacity (CR) of 3mm thick enamel-dentin complex was (87.4 (0.1)). SIGNIFICANCE: The application of this method on a larger group of subjects of different ages may serve as a database for a more exact characterization of optical properties of natural enamel and dentin.

Influence of mechanical and chemical degradation on surface gloss of resin composite materials.

PURPOSE: To determine the changes in surface gloss of different composite materials after simulation of mechanical and chemical aging mechanisms. METHODS: 36 specimens were fabricated for each material and polished with 120-, 220-, 500-, 1200-, 2400- and 4000- grit SiC abrasive paper, respectively. Gloss measurements were made with a glossmeter (Novo-Curve) prior to testing procedures. Specimens of each material were randomly divided into three groups. Group 1 was conditioned for 7 days at 37 degrees C in 75% ethanol aqueous solution. Group 2 was immersed in fluoride gel (Elmex Gelée) at 37 degrees C for 1 hour. Group 3 was subjected to simulated toothbrushing with an electric toothbrush while being immersed in toothpaste. Surface gloss measurements were made subsequently. RESULTS: Significant difference between surface gloss of the composite materials tested were detected after simulated brushing (Kruskal Wallis, P < 0.05). With the exception of Filtek Silorane, all composite materials tested were significantly affected by immersion in Elmex Gelèe (Wilcoxon signed-rank test, P < 0.05). Immersion in 75% alcohol aqueous solution significantly affected surface gloss except natural enamel and Durafill (Wilcoxon signed-rank test, P< 0.05).

Spectrophotometric evaluation of the efficacy of a new in-office bleaching technique.

OBJECTIVE: To quantitatively test the hypothesis that a new paint-on bleaching gel has the potential to lighten tooth color in clinical situations and to evaluate the change of the tooth color six months after the bleaching procedure. METHOD AND MATERIALS: Ten adult subjects requesting tooth bleaching were selected to participate in this randomized clinical trial involving a new in-office bleaching technique using VivaStyle Paint On Plus (Ivoclar Vivadent), originally designed as an over-the-counter bleaching gel. Digital images and CIE Lab spectrophotometric measurements were taken at baseline (I), after the bleaching treatment (PB), and 6 months after bleaching (6M). Differences in Lab values were tested with a repeated measures analysis of variance (ANOVA). Differences in Delta E values were tested with a factorial ANOVA. RESULTS: Significant (P < .05) differences were detected in L, as well as in a and b values, between initial (I) and post-bleaching (PB) and between initial (I) and 6 months post-op (6M). In contrast, there was no significant difference between post-bleaching (PB) and 6 months post-op (6M). CONCLUSION: This new bleaching technique proved to be efficient over a period of 6 months. It could be a less aggressive and more convenient alternative to traditional bleaching techniques.

Minimally invasive treatment of white spot enamel lesions.

This article describes a technique used to treat superficial white spot lesions by a minimally invasive approach. The proposed technique is based on reactivation of enamel by elimination of its hypermineralized external layer through microabrasion, followed by daily home application of casein phosphopeptide-amorphous calcium phosphate complexes (CCP-ACP). The technique may allow elimination of white spot lesions without involving restorative procedures. Microabrasion followed by long-term daily home application of CCP-ACP may be considered an interesting alternative to the restorative approach for treatment of white spot lesions.

Indications and limits of the microabrasion technique.

This clinical report illustrates with clinical cases the indications and limits of microabrasion in patients with discolored anterior teeth. The proposed techniques are based on the elimination of the dysplastic external enamel layer through microabrasion, completed by home bleaching and the use of modern adhesive restorative techniques, if necessary. In specific cases, the proposed technique may eliminate dysplastic enamel lesions without being invasive. The use of minimally invasive techniques based on microabrasion allows for treatment of slight enamel defects. In more severe cases, megabrasion combined with a minimally invasive adhesive resin composite restoration may present a valuable alternative to microabrasion.