Tooth discoloration induced by calcium silicate–based cements: effect of dentin surface pre-treatments in regenerative endodontics

This in vitro study evaluated whether dentin bonding agent application or Nd: YAG laser irradiation can reduce tooth discoloration induced by different calcium silicate-based cements (CSCs) under blood-contaminated conditions simulating regenerative endodontic procedures. Ninety extracted human maxillary incisors were standardized and randomly assigned to nine groups (n = 10) according to pre-treatment strategy (no treatment, universal adhesive, or Nd: YAG laser) and CSC type (ProRoot MTA, Biodentine, or TheraCal PT). Following blood application and clot formation, Spongostan and the assigned CSC were placed in the coronal third of the canal. Specimens were restored with resin composite and stored at 37 °C and 100% humidity. Color measurements were performed spectrophotometrically at baseline and after 7, 30, 90, and 180 days. Color changes were calculated using ΔE₀₀ and whiteness index difference (ΔWID) values. Data were analyzed using three-way repeated-measures ANOVA and Sidak post hoc tests (α = 0.05). All groups exhibited time-dependent discoloration. In ProRoot MTA groups, both dentin bonding agent and Nd: YAG laser pre-treatments significantly reduced discoloration compared with untreated controls (p < 0.05), with no significant difference between the two approaches (p > 0.05). Biodentine and TheraCal PT demonstrated significantly greater color stability than ProRoot MTA (p < 0.05). Within the limitations of this study, neither dentin bonding agent nor Nd: YAG laser pre-treatment completely prevented CSC-related discoloration. ProRoot MTA showed the greatest discoloration potential, even after preventive dentin pre-treatment, and therefore may not be the preferred material for anterior regenerative endodontic cases in which esthetics are critical. Biodentine and TheraCal PT demonstrated better color stability and may be more suitable alternatives for esthetically demanding regions, while dentin bonding or Nd: YAG laser pre-treatment appears to provide only limited, material-dependent benefit.