PH GRADIENTS INDUCED BY UREA METABOLISM IN ARTIFICIAL MOUTH MICROCOSM PLAQUES

被引:20
作者
SISSONS, CH
WONG, L
HANCOCK, EM
CUTRESS, TW
机构
[1] Dental Research Unit, Health Research Council, Wellington School of Medicine, Wellington
关键词
PH; MICROCOSM PLAQUE; UREA; PLAGUE PH GRADIENTS;
D O I
10.1016/0003-9969(94)90147-3
中图分类号
R78 [口腔科学];
学科分类号
1003 ;
摘要
Evidence was sought for urea-induced pH gradients in dental plaque microcosm biofilms cultured from the mixed salivary bacteria in a multi plaque 'artificial mouth'. Application of 500 mmol/l urea for short periods (6 min) to 5-8 mm maximum-thickness plaques induced intraplaque pH gradients of up to 0.7 pH units with the surface alkaline relative to the inner plaque. These pH gradients persisted for more than 5 h in the absence of a flow of fluid. With 30-min urea applications and a flow of a basal medium containing mucin (BMM, pH 7.0), the pH of the inner (deeper) plaque regions also increased. Although the pH gradient initially formed was alkaline at the plaque surface, the BMM flow lowered the surface pH to neutrality whilst the inner layers were still alkaline, thereby reversing the pH gradient. In thick microcosm dental plaques, urea-induced pH gradients can therefore form and last many hours. They probably result from the significant time taken for urea to penetrate to the inner layers of plaque, its rapid metabolism by the outer plaque layers, and a rate-limiting clearance of ammonia. Even a slow BMM flow over the plaque greatly increased the rate of return to the resting pH, causing the gradients to change polarity.
引用
收藏
页码:507 / 511
页数:5
相关论文
共 29 条
[21]   THE SOURCE OF VARIATION IN UREOLYSIS IN ARTIFICIAL PLAQUES CULTURED FROM HUMAN SALIVARY BACTERIA [J].
SISSONS, CH ;
HANCOCK, EM ;
CUTRESS, TW .
ARCHIVES OF ORAL BIOLOGY, 1988, 33 (10) :721-726
[22]   INVITRO UREA-DEPENDENT PH-CHANGES BY HUMAN SALIVARY BACTERIA AND DISPERSED, ARTIFICIAL-MOUTH, BACTERIAL PLAQUES [J].
SISSONS, CH ;
CUTRESS, TW .
ARCHIVES OF ORAL BIOLOGY, 1987, 32 (03) :181-189
[23]   KINETICS AND PRODUCT STOICHIOMETRY OF UREOLYSIS BY HUMAN SALIVARY BACTERIA AND ARTIFICIAL MOUTH PLAQUES [J].
SISSONS, CH ;
CUTRESS, TW ;
PEARCE, EIF .
ARCHIVES OF ORAL BIOLOGY, 1985, 30 (11-12) :781-790
[24]   A MULTI-STATION DENTAL PLAQUE MICROCOSM (ARTIFICIAL MOUTH) FOR THE STUDY OF PLAQUE GROWTH, METABOLISM, PH, AND MINERALIZATION [J].
SISSONS, CH ;
CUTRESS, TW ;
HOFFMAN, MP ;
WAKEFIELD, JS .
JOURNAL OF DENTAL RESEARCH, 1991, 70 (11) :1409-1416
[25]   PH RESPONSES TO SUCROSE AND THE FORMATION OF PH GRADIENTS IN THICK ARTIFICIAL MOUTH MICROCOSM PLAQUES [J].
SISSONS, CH ;
CUTRESS, TW ;
FAULDS, G ;
WONG, L .
ARCHIVES OF ORAL BIOLOGY, 1992, 37 (11) :913-922
[26]  
Stephan Robert M., 1944, JOUR DENTAL RES, V23, P257, DOI 10.1177/00220345440230040401
[27]   STUDIES OF THE MICROBIOLOGY OF CARIES .3. THE BUFFER CAPACITY OF THE DENTAL PLAQUES [J].
STRALFORS, A .
JOURNAL OF DENTAL RESEARCH, 1948, 27 (05) :587-592
[28]   DIFFUSION OF RADIOTRACERS IN HUMAN DENTAL PLAQUE [J].
TATEVOSSIAN, A .
CARIES RESEARCH, 1979, 13 (03) :154-162
[29]  
[No title captured]