So simple rule, the suffering of small, low-cost dental caries, gingivitis into the treatment of complicated, painful, expensive dental pulp and periodontal disease.

• 使简单易治、痛苦小、费用较低的龋齿、牙龈炎发展成治疗复杂、令人痛苦、费用较高的牙髓病和牙周炎。