Influence of coffee on color stability of direct/ indirect veneers: A systematic review

Objectives: Over time, there has been a development in veneer materials, changes in preparations, and improvements in veneer cementation. Multiple research have assessed the impact of coffee on various physical characteristics of both direct and indirect veneers, as well as the materials utilized in their fabrication. The attribute of veneers that has received the most extensive research is their color stability. This systematic review aimed to study the effect of coffee as a beverage on color stability of direct and indirect veneers. Material and Methods: The current investigation was done according to the PRISMA 2020 Guidelines. The procedure for the systematic review was recorded in PROSPERO (CRD42024519382).A systematic qualitative search was conducted in two databases (PubMed, Scholar) until January 18, 2024. Two independent reviewers executed the search strategy, screened and selected studies, extracted methodology and result data, and assessed the internal methodological risk of bias. Strict inclusion and exclusion criteria were followed. The titles of the studies and their respective abstracts were reviewed independently by two authors in accordance with the inclusion criteria in order to choose the studies. The authors of the current review reached a consensus on the final inclusion of research after fully evaluating and screening the texts. “Modified CONSORT checklist of items for reporting in vitro studies of dental materials" assessed the bias. The study's final evaluation involved assigning a risk of bias of "low," "medium," or "high" to each researched aspect. The fulfillment or non-fulfillment of each of the 14 characteristics considered in the quality assessment was evaluated individually, and the percentage of compliant items was calculated using the formula (number of compliant items/total number of items x 100). Results: From the identified 1014 studies, 23 in-vitro studies were included for systematic review after removal of duplicates and strictly following the inclusion criteria. Among the studies reviewed, 37 different veneer materials were examined. The studies that were retrieved used various artificial staining techniques. Coffee is investigated in this review as a staining solution. The CIEDE2000 color difference formula and CIELAB formula was used for color assessment in the included studies. Four studies had low risk of bias (RoB) while remaining studies had medium risk of bias. Analysis revealed better color stability of indirect veneers when compared with direct veneers. Conclusions: This current study reviewed the effect of coffee on the various materials used for veneers. Based on current evidence, coffee definitely has a major impact on color stability of veneers. Resin materials that are machined instead of direct or prefabricated exhibit greater color stability. Indirect or direct materials do not exhibit the same color stability as resin-based blocks used in CAD/CAM processes.