Dnj. Ricketts et al., A REEVALUATION OF ELECTRICAL-RESISTANCE MEASUREMENTS FOR THE DIAGNOSIS OF OCCLUSAL CARIES, British Dental Journal, 178(1), 1995, pp. 11
Clinical and radiographic diagnosis of occlusal caries is difficult. R
esistance measurements in pits and fissures have shown better sensitiv
ity compared with the more conventional methods of diagnosis. Two mach
ines have been manufactured for this purpose: the Vanguard and the Car
ies Meter L. The aims of this study were to calibrate the readouts of
these machines against a variable standard resistance box and use the
Vanguard to compare readings taken in vivo and in vitro after extracti
on of the teeth. The diagnositc accuracy of clinical, radiographic, Va
nguard and Caries Meter L diagnoses were also assessed. One hundred oc
clusal sites in 40 teeth of 20 patients were investigated in vivo with
the Vanguard, noting clinical and radiographic appearances. The teeth
were then extracted and the Vanguard readings repeated in vitro, toge
ther with Caries Meter L readings. The in vivo/in vitro comparison bet
ween Vanguard readings showed excellent reproducibility (Cohen's Kappa
= 0.80). The sensitivity and specificity for the different examinatio
n techniques at the enamel level of diagnosis were 27% and 89% for vis
ual, 6% and 100% for radiographic, 81% and 78% for the Vanguard and 74
% and 74% for the Caries Meter L. In conclusion, this study supports t
he renewed interest in resistance measurements as a diagnostic techniq
ue and indicates that the in vitro model used gives results comparable
to those in vivo.