Diagnostic Accuracy of a Bioluminescence System for the Assessment of Caries Activity on Occlusal Surfaces.

OBJECTIVE: Assessment of caries lesion activity is usually performed using visual-tactile criteria. A new approach is to use a system consisting of a photoprotein, which is specific for free calcium ions, along with an integrated camera that visualizes the elevated calcium ions on the lesion as a light signal (bioluminescence). This study aimed to evaluate the reproducibility and diagnostic accuracy of a newly developed bioluminescence system to assess caries lesion activity on occlusal surfaces in vitro. MATERIALS AND METHODS: Ninety-four extracted permanent teeth with sound surfaces and both active and inactive caries lesions were included. The extent and activity of the investigation sites were classified visually according to the International Caries Detection and Assessment System. Digital images of the teeth were produced by the bioluminescence system and the images were analyzed for the presence of caries activity (the bioluminescent areas at the investigation sites). The images were reanalyzed after 4 weeks. Teeth were hemisected and methyl red dye was applied on the sections to validate lesion activity histologically. RESULTS: Agreement between the bioluminescence readings was shown by κ values of 0.802-0.917. A significant positive correlation (p < 0.001) was found across all methods (rs 0.618-0.811). Sensitivity and specificity for activity assessment using histology as the gold standard (cut-off: active/inactive) were, respectively, 83.6 and 85.0% for the visual assessment, and 92.5 and 90.0% for the bioluminescence method. Comparison of areas under the receiver-operating characteristic curves showed no significant difference between the visual and bioluminescence systems (p = 0.094). CONCLUSION: The bioluminescence system demonstrated high in vitro reproducibility and good diagnostic accuracy for activity assessment of caries lesions on occlusal surfaces which were not significantly different from the values obtained in the visual assessment.

Quantitative evaluation of root canal surface roughness after filing with adaptive reciprocating and continuous rotary instruments.

Obtaining clean and smooth root canal walls is the ideal clinical outcome of the cleaning and shaping stage in root canal treatment. This study compares the surface roughness of root canal surfaces instrumented with a NiTi filing system with either adaptive reciprocating (AR) or continuous rotation (CR). Root canal cleaning and shaping was carried out on the mesial canals of 24 extracted first molars roots with either AR or CR. Roots were split in half and the surface roughness of their canals was evaluated in 12 three dimensional roughness reconstructions using a scanning electron microscope. Rz (nm) values were calculated in three areas of each reconstruction and analyzed (α = 0.05). Mann-Whitney tests showed that surface roughness was significantly higher overall in the AR group (Rz = 967 ± 250 nm) compared with the CR group (Rz = 739 ± 239 nm; p = 0.044). The roughness values generally increased from apical towards the coronal third in both groups. A less aggressive finishing file or a continuous rotary system to end the cleaning and shaping stage may be beneficial to reduce roughness of the root canal surface.

Effect of storage environment on the bond strength of reattachment of crown fragments to fractured teeth.

AIM: The aim of this study was to examine various storage environments for storing fragments before being bonded to the remaining teeth and also estimate the required force to fracture the restored teeth. MATERIALS AND METHODS: Sixty mandibular incisor teeth were fractured on the incisal one-third and were divided into five groups of 12 each to be stored in normal saline, water, milk, saliva and dry environments for 24 hours. All the fractured parts in each group were bonded to their relevant apical parts by an etch and rinse bonding system and a flowable composite resin. The fracture resistance was measured by a universal testing machine, and the results were analyzed using one-way ANOVA and Tukey statistical tests. RESULTS: The results revealed that the difference among the five groups was statistically significant (P<0.001). Tukey tests showed that the force required for fracturing fragments kept in the milk and saliva environments were significantly higher than those for the normal saline, water and dry environments (P<0.05 ). CONCLUSIONS: It was concluded that keeping the fractured parts in milk and saliva environments can increase the required force for fracturing teeth more than the other environments.