October 2006
Volume 2, Issue 8

Diagnodent Measurements and Correlation with the Depth and Volume of Minimally Invasive Cavity Preparations

Howard E. Strassler, DMD

Hamilton JC, Gregory WA, Valentine JB.  Oper Dent. 2006;31(3):291-296.


In this clinical study, DIAGNOdent (KaVo) was used to assess previously diagnosed carious lesions in the pits and fissures of first and second molars. The measurements from this device were correlated with the depth and volume of the cavity preparations that resulted from minimal intervention to remove occlusal carious lesions. Twenty-five patients, 18 years of age or older, who were previously scheduled for an occlusal restoration due to caries, were recruited and enrolled in this clinical study. These patients had 48 qualifying teeth without previous restorations, sealant or other carious lesions. The occlusal surface of each study tooth was cleaned utilizing ProphyFlex2 (KaVo). Two dentists separately traced the pit and fissure system of each tooth using the DIAGNOdent for two 15-second periods each. The peak reading of each of the four measurements were recorded. An impression of the occlusal surface of each tooth was recorded with a polyvinyl siloxane bite registration material. The carious lesions were removed with an air abrasion unit employing a 0.015-inch nozzle opening utilizing minimal operative intervention. A low viscosity polyvinyl siloxane was used to take an impression of the cavity preparation impression, using the bite registration impression to form the occlusal surface of the preparation impression. The preparation impression volume was calculated from its weight using the known density of the impression material. The greatest depth of the preparation was measured. The Pearson correlation coefficient was used to investigate any relationship between depth or volume of the preparation impression and the DIAGNOdent measurements. The correlation for the preparation volume and maximum DIAGNOdent measurement was 0.191 (p= 0.189). Other logical subsets of cases also did not result in any statistically significant correlations between DIAGNOdent readings and the depth or volume of the final cavity preparation.


Clinical research and observations in the past quarter century have led to changes in the way pit-and-fissure caries is detected, diagnosed, and treated. The difficulty in establishing a diagnosis of pit-and-fissure caries is due to the increased use of fluoride. DIAGNOdent, a laser fluorescent unit, is being used as an aid in caries diagnosis. In other research, the peak reading of the device has been suggested to determine depth of the carious lesion on the occlusal surface. This study investigated whether or not there is a correlation between peak reading of the DIAGNOdent and carious lesion depth orand volume of caries. The device uses laser fluorescence of carious tooth structure when compared to the lack of fluorescence of healthy tooth structure. This study demonstrates that the peak value of the DIAGNOdent cannot be used to predict size or depth of a carious lesion and only the presence or absence of caries within tooth structure on the occlusal surfaces of posterior teeth. Clinicians using this laser fluorescence caries diagnosing device need to be careful to prepare diagnosed caries carefully to conserve healthy tooth structure without having an expectation of the final preparation size based upon the peak readings of the device.

About the Author
Howard E. Strassler, DMD
Professor and Director of Operative Dentistry
Department of Endodontics, Prosthodontics and Operative Dentistry
University of Maryland Dental School, Baltimore, Maryland

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