Color stability of resin-based composites: Staining procedures with liquids-A narrative review.

Abstract

The objective of this study was to review the experimental staining procedures performed in in-vitro studies for evaluating color stability of resin-based composites used for direct restorations. A review was performed with the purpose to identify in vitro procedures carried out to establish staining and color stability of resin-based composites used for direct restorations. A literature search was performed on four online databases (PubMed, Scopus, Embase and Web of Science) for articles published from January 1st 2001 till March 20th 2021, using a combination of free words and Medical Subject Headings (MESH) terms: "Composite Resins" AND "Color Stability" OR "Staining." Two reviewers screened titles and/or abstracts of 1728 unique studies. In total, 208 studies were selected for full-text reading, from which 178 were included in the review. The assessed variables were specimen dimensions, shape, and surface finishing; time before immersion; staining media type, dwell time, temperature and renewal interval; type of composite; color and translucency assessment parameters and measuring system. One hundred and seventy-eight articles analyzed color stability with staining liquids. Coffee was the most used staining medium (n=102), followed by tea (n=61), and red wine (n=55). A disc-shaped specimen was used in most studies (n=170) with a 2 mm thickness (n=116). Spectrophotometers were the most used color assessment devices (n=154), followed by colorimeters (n=17). Color differences were quantified with ΔE (n=154), ΔE00 (n=23). Acceptability and or perceptibility thresholds were also taken into consideration (n=126). The large variety of staining procedure suggests the need for standardization. Aesthetic failure due to discoloration is a relevant clinical problem. Evaluating benefits and drawbacks of resin based composites artificial staining procedures will improve to predict materials clinical performances.