Perceptibility and acceptability thresholds for colour differences in dentistry.

Introduction: Data on acceptability (AT) and perceptibility thresholds (PT) for colour differences vary in dental literature. There is consensus that the determination of ΔE* is appropriate to define AT and PT, however there is no consensus regarding the values that should be used. The aim of this clinical review was to provide a systematic approach to the topic of colour science of high clinical relevance to dental research.

Materials And Methods: MEDLINE/PubMed, WoS and EBSCO databases were searched up to January 7, 2013; the outcome was restricted to English, and to clinical studies were spectrophotometers were used for measurement.

Results: Forty-eight studies were eligible and met the inclusion criteria. Of the 48 studies there appeared to be a trend in their source references: 44% referred to the same study for the PT (ΔE*=1); and 35% referred to the same article for the AT (ΔE*=3.7).

Conclusions: More than half the studies defined PT as ΔE*=1, and one third of the studies referred to ΔE*=3.7 as the threshold at which 50% of observers accepted the colour difference. Most clinical studies refer to the same few in vitro literature that have attempted to determine PT and AT from decades ago.