Staining reaction of dental plaque after various extraction procedures

After water and dilute alkali extraction, a sample of dental plaque that was stained by the PA-CrA-silver technique showed staining intracellularly on the cell wall and extracellularly. When more prolonged and stronger alkali extraction was used, reacting material was retained on the cell wall and intracellualarly. There was a noticeable loss of extracellular reacting material.