In vitro colour stability of aesthetic brackets

Abstract

Contrary to their popularity in satisfying aesthetic demands, plastic brackets still present some problems because of their decreased hardness and wear resistance. A problem of plastic brackets is discolouration, due to ultraviolet (UV) light and food dyes. The aim of this study was to investigate the colour stability of aesthetic brackets during UV irradiation and exposure to food dyes. Four different polymer brackets were exposed in a Suntest CPS+ ageing device to a xenon lamp to simulate natural day light. Because most tooth-coloured bracket systems are used in adult treatment, red wine, coffee, and tea were chosen as food colourants. After 24 and 72 hours of exposure, colour measurements were performed by means of a spectrophotometer according to the CIE L*a*b* system and colour changes (DeltaE*) were computed. Statistical differences were investigated using three-way analysis of variance (ANOVA). With the exception of the Aesthetic-Line bracket, almost all investigated polymer brackets showed clinically unacceptable discolouration during in vitro exposure to colourants. Most of the brackets became yellower after UV light treatment. In spite of the short exposure period of 72 hours, almost all polymer brackets showed undesirable discolouration. These current in vitro findings indicate that even newly developed plastic brackets, consisting of composite materials or modern polymers (polyoxymethylene) may have clinically unacceptable colour stability in the long-term.

Retentive forces and fatigue resistance of thermoplastic resin clasps

“…The most widely used appliances were the esthetic clasps of partial removable dental prostheses [1, 10,58,61], cast posts and cores [11,42] and brackets [18].…”

Torque Stability of Plastic Brackets Following Multiple Loading and Artificial Material Aging – an In-Vitro Comparison

“…However, as plastic is softer than ceramic, deviations from the pre-programmed torque values can occur. Another disadvantage is the tendency to discolor, especially during treatments of longer duration [12,18].…”

“…Allerdings kann es durch die verminderte Härte des Kunststoffes zu Abweichungen in den einprogrammierten Torquewerten kommen. Ein weiterer Nachteil ist die Neigung zur Verfärbung, insbesondere bei lang andauernden Behandlungen [12,18].…”

Assessment of Exogenous Pigmentation on Clear Elastomeric Modules: An in vitro Study

“…Immersion of the food substance for Seventy-two hour is adequate to simulate the clinical interruption and exposure of the elatomeric modules to staining diet substances during the 3 weeks appointment interval. 5,8 The hue, saturation & intensity of group A changed significantly after staining with methylene blue. Hue changed significantly with methylene blue in group B, saturation & intensity changed with coffee & tea.…”