近廿年来,由于一些国家提供了优良的口腔保健服务和采取了众多的预防措施,致使曾一度非常流行的龋病逐步得以控制,出现下降趋势。当然,即使在这些国家,龋病仍是危害人类的最重要疾病之一。应该指出,牙科流行病学至今仍是相对不成熟的一门学科。在大多数国家,15～20年 In the last 20 years, as some countries provided excellent oral health services and adopted many preventive measures, the ever-prevailing caries was gradually brought under control with a downward trend. Of course, even in these countries, caries remains one of the most important diseases that endanger humans. It should be pointed out that dental epidemiology is still a relatively immature subject. In most countries, 15 to 20 years