OpalDam Green 20 - 1.2 ml Syringes. Liquid dam, resin barriers used to isolate and protect soft tissue with an impervious seal. It applied directly and removed easily, giving you peace of mind without sacrificing efficiency. Light-reflective properties focus heat away from the teeth and gingiva for patient comfort. OpalDam Green contrasts perfectly with teeth, gingiva and boosting gels, making it ideal for use during in-office whitening procedure. Protects soft tissue with impervious seal. Removes easily. Light-reflective properties focus heat away from the teeth and gingiva for patient comfort. Applies directly. OpalDam Econo Refill: 20 x 1.2 ml Syringes. Liquid dam, resin barriers used to isolate and protect soft tissue with an impervious seal.It applied directly and removed easily, giving you peace of mind without sacrificing efficiency. Light-reflective properties focus heat away from the teeth and gingiva for patient comfort.