Abstract: Disclosed are chemical agents with unexpected antimicrobial activity against the microbes, especially Porphyromonas gingivalis, known to be important in the cause and progression of gingivitis, periodontitis, and destruction of hard and soft oral tissues leading to tooth loss. The agents have additional unexpected anticollagenase activity useful in the direct mitigation of tissue damage. The agents can be formulated to produce various compositions and dental implements useful in management of peridental diseases, particularly those involving infection with certain gram-negative anaerobes.