Non-invasive monitoring of gingival crevicular fluid for estimation of blood glucose level

Abstract

Development of a non-invasive method for measuring the blood glucose level is an urgent necessity, and putting such a method into practical use will enable some of the physical and mental stress that patients with diabetes have to endure to be removed. To realise a non-invasive blood glucose monitor, the gingival crevicular fluid (GCF) was measured. A GCF-collecting device was developed that was designed to be disposable, biocompatible and small enough to be inserted in the gingival crevice for collection of a sub-microlitre sample of GCF. Also, a high-sensitivity glucose testing tape incorporated in the device was developed. Red laser light in a portable optical device measured the colour density of the testing tape. Standard glucose solutions were used to investigate the measurement accuracy of the GCF glucose monitor and showed a correlation coefficient of R = 0.99 (n = 20) between the optical density and the glucose levels. The GCF glucose monitor was evaluated on healthy Swedish and Japanese adults (n = 10) and both GCF glucose levels (GCFLs) and blood glucose levels (BGLs) were measured in conjunction with meal loads. The GCFLs were about 1/10-1/560 lower than the BGLs. No difference in the range of GCFLs between the Swedish and the Japanese subjects was observed. Therefore it was concluded that physique, body mass index and life-style, such as dietary habit, did not significantly influence the GCFLs. Further, the correlation coefficients of all the subjects were 0.70 and 0.88 with each group. It was suggested that GCF could be used as a method of non-invasive blood glucose measurement.

Evaluation of Time-Course Changes of Gingival Crevicular Fluid Glucose Levels in Diabetics

“…The correlation coefficient was lower than the one Parker reported as 0.975 (1993). However, it was almost the same result as the correlation coefficient, between 0.705 and 0.877, that the authors indicated for healthy subjects (Yamaguchi et al, 2004). The diabetes period was not considered to influence the GCF glucose level with regards to the subject with the diabetes period for 4.8 ±1.7 yr (mean ± SD).…”

“…The use of GCF-collecting device with a testing tape saturated with enzyme as a collecting tape, simultaneous analysis of GCF could be possible (Yamaguchi et al, 2001(Yamaguchi et al, , 2002a(Yamaguchi et al, , 2002b(Yamaguchi et al, , 2004. In addition, not only the use of the non-invasive blood glucose level measurement via GCF, but also the application to qualitative and quantitative analyses for various diseases will be the subject of further study.…”

“…Since the GCF was collected only from either the incisor or canine teeth gingival crevice, collection was easily performed without causing any pain to the subjects. In the previous study, GCF collecting took about one to two minutes; however, it could be shortened to 5 to 30 s (Yamaguchi et al, 2004). Consequently, variations in collecting time among the subjects could be reduced.…”

“…Furthermore, the stimulating test using guinea pigs revealed that insertion of the GCF-collecting device into the gingival crevice would not cause any long-term problems (Yamaguchi et al, 2002b). Also, the results of the meal load test using healthy subjects demonstrated that the blood glucose level correlated well with the GCF glucose level, with a correlation coefficient of more than 0.9 (Yamaguchi et al, 2004). However, it was revealed that improvement in the device to allow visual confirmation of sample collection was required for the method to be practically applied.…”

A Novel Exclusion Mechanism for Carbon Resource Partitioning in Aggregatibacter actinomycetemcomitans

“…The gingival crevice contains a robust microbial population that is consistently bathed in crevicular fluid, which differentiates it from the tooth surface, which is immersed in saliva. Crevicular fluid is a plasma exudate that passes through the gingiva and flows along the teeth (20) and contains a number of potential carbon sources including sugars, small acids, and amino acids (6,11,20,48). A. actinomycetemcomitans primarily resides in the "moderate" pockets (4 to 6 mm in depth) in the gingival crevice instead of the deeper portions (9).…”