Yukiteru Iwami1, Norifumi Hayashi, Fumio Takeshige, Shigeyuki Ebisu. 1. Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8, Yamadaoka, Suita, Osaka 565-0871, Japan. y-iwami@dent.osaka-u.ac.jp <y-iwami@dent.osaka-u.ac.jp>
Abstract
OBJECTIVES: To investigate the relationship between the color of carious dentin with varying lesion activity, and bacterial detection in the lesions. METHODS: In 26 extracted human molars with coronal dentin caries and four extracted sound human molars, dentin was removed by a round bur every 150 microm from the dentin surface, in the direction of the pulp chamber. Before and after removal, images of nine-color samples and the dentin surface stained with a caries detector dye (1% acid red in propylene glycol) were taken simultaneously by a charge-coupled device (CCD), and dentinal tissue samples were taken with a new round bur. From the images, corrected L*, a* and b* values (CIE 1976 L*a*b* color system) of the dentin surfaces were calculated from the color changes of the nine-color samples. Bacterial DNA in the dentinal tissues was detected by polymerase chain reaction. RESULTS: Before removal of dentin, the L* of sound molars (L*>50) was significantly larger than that of carious molars (L*<50) (ANOVA, Scheffe's F-test, P<0.05). In addition, the carious molars were divided into type I (a*>20, characteristics of active caries) and type II (a*<20, characteristics of arrested caries), and there was a significant difference in the a* value (P<0.05). For both carious types, the area under the receiver operating characteristic curve of L* was significantly larger than that of a* or b* (univariate Z score test, P<0.05), and the rate of bacterial detection decreased as the L* of dentinal tissue increased, and bacterial DNA was not detected when L* was >60. CONCLUSIONS: Sound and types I and II carious dentin were discriminated by the combination of L* and a* values of dentinal tissue stained with the caries detector dye before removal of dentin. In carious lesions, the a* values of carious dentin stained with the dye were related to the carious lesion activity before removal of carious tissue, and the L* values were related to the degree of caries progression.
OBJECTIVES: To investigate the relationship between the color of carious dentin with varying lesion activity, and bacterial detection in the lesions. METHODS: In 26 extracted human molars with coronal dentin caries and four extracted sound human molars, dentin was removed by a round bur every 150 microm from the dentin surface, in the direction of the pulp chamber. Before and after removal, images of nine-color samples and the dentin surface stained with a caries detector dye (1% acid red in propylene glycol) were taken simultaneously by a charge-coupled device (CCD), and dentinal tissue samples were taken with a new round bur. From the images, corrected L*, a* and b* values (CIE 1976 L*a*b* color system) of the dentin surfaces were calculated from the color changes of the nine-color samples. Bacterial DNA in the dentinal tissues was detected by polymerase chain reaction. RESULTS: Before removal of dentin, the L* of sound molars (L*>50) was significantly larger than that of carious molars (L*<50) (ANOVA, Scheffe's F-test, P<0.05). In addition, the carious molars were divided into type I (a*>20, characteristics of active caries) and type II (a*<20, characteristics of arrested caries), and there was a significant difference in the a* value (P<0.05). For both carious types, the area under the receiver operating characteristic curve of L* was significantly larger than that of a* or b* (univariate Z score test, P<0.05), and the rate of bacterial detection decreased as the L* of dentinal tissue increased, and bacterial DNA was not detected when L* was >60. CONCLUSIONS: Sound and types I and II carious dentin were discriminated by the combination of L* and a* values of dentinal tissue stained with the caries detector dye before removal of dentin. In carious lesions, the a* values of carious dentin stained with the dye were related to the carious lesion activity before removal of carious tissue, and the L* values were related to the degree of caries progression.
Authors: Maryann Lehmann; Analia Veitz-Keenan; Abigail G Matthews; Donald Vena; Ashley Grill; Ronald G Craig; Frederick A Curro; Van P Thompson Journal: J Am Dent Assoc Date: 2012-04 Impact factor: 3.634