摘要:Proteolytic enzymes in dental plaque are important elements in the pathophysiology of periodontal disease and are putative virulence factors. The effect of sucrose intake versus a sucrose-free diet (substituting glucose for sucrose) on numbers of isolates from early dental plaque expressing extracellular proteolytic enzymes able to hydrolyse gelatin and azocoll was studied. The bacteria were isolated from 0-3 d dental plaque formed on the buccal surface of a lower premolar in six subjects. A total of 7987 isolates were tested. Sucrose intake was associated with lower numbers of isolates expressing proteolytic activity at the start of plaque formation and higher numbers in 2 and 3 d plaque. Limitations of current methods for cultural studies of developing dental plaque are discussed, and the need for improved methods to study the nature and activities of all microorganisms colonising the teeth is stressed.Keywords: sucrose intake, dental plaque, proteolytic activity, virulence factors, validity, plaque ecology.