Kits and methods facilitate chair-side coating of an endodontic cone for improved sealing between the hydrophilic root canal tissue, the hydrophobic elastomer substrate of the endodontic cone, and a hydrophilic sealing resin. The kit includes one or more endodontic cones (e.g., formed of gutta percha) and a micro-dose container containing an adhesive composition. The practitioner can dip the cones into the adhesive composition so as to coat the cones chair-side, just prior to use. The adhesive composition includes an adhesive resin compound comprising at least one hydrophobic region and at least one hydrophilic region. The hydrophobic region is compatible with the hydrophobic elastomer substrate of the endodontic cone, while the hydrophilic region is compatible with a hydrophilic endodontic sealing resin.