Clinical characteristics of patients with chronic periodontitis and healthy control subjects.

aAPI, Approximal Plaque Index.bSBI, Sulcus Bleeding Index.cPIRI, Periodontal Index of Risk of Infectiousness.dPversus healthy subjects). Data are shown as mean±standard deviation (mean±SD).

a. 近似菌斑指数（Approximal Plaque Index，API）；b. 龈沟出血指数（Sulcus Bleeding Index，SBI）；c. 牙周感染风险指数（Periodontal Index of Risk of Infectiousness，PIRI）；d. 与健康受试者对比。数据以平均值±标准差（mean±SD）形式呈现。