Comparison of the Diagnostic Power of Diagnodent and Phosphor Plate Radiography to Detect Secondary Caries in Class II Cavities

 It is of utmost importance to achieve a non-invasive method to diagnose secondary caries next to amalgam restorations. In many cases, clinical examination alone does not allow an accurate diagnosis of recurrent and proximal caries; therefore, appropriate radiographs and Diagnodent are required. The use of Diagnodent (laser fluorescence) and intraoral digital x-ray radiography (PSP) is increasing instead of visual inspection and tactile examination. Given the discrepancies in the results of studies about Diagnodent and digital x-ray radiography (PSP) for the detection of secondary caries, this study aimed to compare the diagnostic power of Diagnodet and intraoral digital radiography to detect secondary caries in class II  amalgam restorations.

 In this diagnostic study, 40 healthy human premolar teeth were used. First, 40 class II cavities were prepared and restored with amalgam. In the first stage, the teeth underwent radiography with an intraoral PSP system and saved. The teeth were then immersed in 0.1 mol lactic acid (pH = 4) to simulate recurrent caries for three weeks. Diagnodent was used in the clinical diagnosis to detect recurrent caries. In the final stage, teeth with recurrent caries underwent digital radiography. Finally, two oral and maxillofacial radiologists evaluated all the 80 radiographs. T-test was used to analyze the false-positive (FP) and false-negative (FN) results of the two techniques with SPSS 16 (α = 0.05).

 The study was carried out on 40 teeth using Diagnodent and intraoral PSP radiography. Incorrect diagnoses (FP and FN) were recorded in 28.5% and 21.2% of the cases with digital radiography and Diagnodent techniques, respectively (p value = 0.3).

 Diagnodent and intraoral digital radiography exhibited similar diagnostic power in the detection of secondary caries around class II amalgam restorations.