Methods: 20 cases with periodontitis were exposured by HBO, different periodontal clinical indices of 438 teeth were measured, and the plaque in pocket bottom were analyzed by congo red negative staining.

• 方法 :选 2 0例牙周炎患者 ,用HBO治疗 ,常规方法测定 438个患牙各临床指标的变化 ,用刚果红负性染色法观察袋底菌斑不同形态细菌的变化。