Correlation between the Periapical Index and Lesion Volume in Cone-beam Computed Tomography Images.

INTRODUCTION: The study aimed to correlate the Periapical Index (PAI), obtained by way of periapical radiographs, with the volume of chronic periapical lesion, obtained through cone-beam computed tomography (CBCT), in the permanent teeth. METHODS AND MATERIALS: Radiographs and CBCT images were selected from 35 single-rooted permanent teeth, with fully formed apices, with a diagnosis of pulp necrosis and chronic apical periodontitis that was radiographically visible. Two independent raters evaluated the radiographs on two separate occasions and classified the periapical lesions in accordance with Ørstavik's PAI. The periapical lesion volume was calculated in the CBCT images. The correlation between the PAI and the lesion volume was calculated using Spearman's correlation test. RESULTS: There was a positive, moderate correlation between the PAI and the volume (rs=0.596; P<0.001) where rs2 is equal to 0.355, showing that only 35% of the PAI variation was dependent upon the variation in periapical lesion volume. CONCLUSION: The radiographic evaluation of the periapical lesion does not reflect the lesion's volumetric characteristics as the volume had a moderate effect on the choice of PAI score.

Exploring different photodynamic therapy parameters to optimize elimination of Enterococcus faecalis in planktonic form.

BACKGROUND: The failure of endodontic treatment is linked to the presence of Enterococcus faecalis in the root canals. The scope of this study was to evaluate the influence of the energy dose and frequency of photodynamic therapy (PDT cycles), as well as the volume of bacterial suspensions (BS) in the elimination of Enterococcus faecalis in planktonic form. METHODS: In four successive assays BS of Enterococcus faecalis ATCC 19433 were irradiated with a diode laser (40 mW) using the photosensitizer (PS) methylene blue (MB) (0.005 µg/mL). Group 1 - Effect of energy dose: 100 µâ€¯L of BS and 100 µâ€¯L of PS were irradiated by 1, 2.5, 5, 7.5 and 10 minute s. Group 2 - Effect of PDT cycles: The BS received 1, 2, 3 or 4 PDT cycles (in each cycle 100 m L of PS was added and irradiated by 2.5 minutes). Group 3 - Effect of energy dose and bacterial suspension volume: 10 µâ€¯L of BS and 10 µâ€¯L of PS were irradiated similar to group 1. Group 4 - Effect of energy dose, bacterial suspension volume and PDT cycles: 10 µâ€¯L of BS and 10 µL of PS were irradiated according to group 2. The laser source and MB isolated represented the controls. RESULTS: The mean log reduction after separate applying laser light and MB were 0.01 and 0.07, respectively. It was found that wells with 100 µâ€¯L of BS irradiated with 2.4 to 24 J of energy did not cause significant bacterial elimination (p > 0.05), on the other hand PDT cycles above 12 J increased significantly bacterial elimination (p < 0.05). In 10 µâ€¯L wells irradiation from 12 J of energy provided higher bacterial elimination (p < 0.05) which combined with PDT cycle resulted in the logarithmic elimination of E. faecalis (p < 0.05). CONCLUSIONS: The energy dose, the volume of the bacterial suspension and, especially, the PDT cycles optimized the bacterial elimination of Enterococcus faecalis in planktonic form.

Photodynamic therapy with high-power LED mediated by erythrosine eliminates Enterococcus faecalis in planktonic forms.

BACKGROUND: The failure of endodontic treatment is linked to the presence of microorganisms, particularly Enterococcus faecalis, in the root canals. This study evaluated the effectiveness of photodynamic therapy (PDT) using erythrosine irradiated by a high-power curing light on a planktonic suspension culture of E. faecalis. METHODS: Bacterial suspensions of E. faecalis were adjusted and then mixed in a 1:1 proportion, in triplicate, in treatment groups by varying the length of irradiation time (120 and 240s) and the molarity of the erythrosine (5 and 10µM). In order to verify the post-treatment bactericidal effect, a count of the viable bacteria was performed (CFUmL-1) and transformed into Log10 CFU. The one-way ANOVA with Tukey post-hoc test was applied to check for differences between the groups. RESULTS: The bacteria were completely eradicated in the groups that used PDT with 5µM 240s, 10µM 120s and 10µM 240s (p≪0.001). The effect of the PDT 5µM 120s group was significant (p≪0.05) in comparison with the groups using only light or only erythrosine. Positive control (exposure to 2.5% NaClO for 120 and 240s) completely eradicated E. faecalis. The negative control (PBS) did not alter the quantities of E. faecalis CFU with 9.605 Log10 CFU at 120s and 9.621 Log10 CFU at 240s. CONCLUSION: PDT with erythrosine in a concentration of 10µM and high-power LED is capable of totally eliminating E. faecalis in planktonic suspension.