Systematic review of in vitro studies evaluating tooth bleaching efficacy.

PURPOSE

To review and assess the literature on in vitro studies evaluating tooth bleaching efficacy considering the use of a negative control, type of tooth substrate, storage medium, color evaluation methods, and evaluation time points.

METHODS

The following databases were searched: PubMed (MEDLINE), Web of Science. Search used Medical Subject Headings (MeSH) in PubMed in addition to free text. The following limits were applied: English, articles published between January 1989 and October 2017. Additional free text key terms included: in vitro, tooth bleaching, placebo, negative control, overall CIELAB color change (ΔE*ab), change in shade guide units (ΔSGU), tooth color stabilization, evaluation time points, bovine teeth, and staining. Search was repeated in Web of Science but no additional articles were identified. A total of 11 studies were included for qualitative and quantitative analysis.

RESULTS

The meta-analysis of nine included studies that reported ΔE*ab values, revealed that the NC statistically exceeded the perceptibility threshold (PT) of 1.2 (P< 0.05). The estimate was 2.872 with lower and upper bounds of 1.955 and 3.790, respectively.

CLINICAL SIGNIFICANCE

Randomized controlled trials are gold standards to evaluate bleaching efficacy of different materials. However, in vitro studies offer a way to screen for potential bleaching efficacy. It is vital to determine an appropriate cut-off value for determining bleaching efficacy in vitro and further apply for clinical relevance.