Contrast-enhanced micro-CT to assess dental pulp tissue debridement in root canals of extracted teeth: a series of cascading experiments towards method validation.

AIM: To validate a new method for the evaluation of pulp tissue debridement in the root canals of extracted teeth using an impregnation protocol involving potassium triiodide, a radiocontrast solution known as Lugol's, combined with micro-computed tomographic (micro-CT) imaging. METHODOLOGY: The impact of NaOCl on the radiopacity of Lugol's solution was assessed using a two-fold dilution series of Lugol in distilled water and 5.25% NaOCl, which were then pipetted into transparent dishes and radiographed. To verify the influence of Lugol on the proteolytic effect of NaOCl, a dissolution test was performed using fresh bovine meat. Ten slices did not undergo any tissue processing, whilst twenty slices were fixed in formaldehyde for 24 h. After that, 10 of them were immersed in Lugol for another 24 h. Then, all specimens were placed in NaOCl and the time required for a complete tissue dissolution was recorded. For the last experiments (histological validation and micro-CT assessment), 8 extracted mandibular premolars with formerly vital pulps were immersed in buffered formalin, scanned in a micro-CT device, accessed, immersed in Lugol for 7 days and scanned again. Then, the root canals of 5 teeth were prepared and scanned, and the volume of remaining pulp tissue identified and quantified, whilst 3 teeth were histologically processed. The same specimens were subjected to histological assessment, and the images of the histologic sections were registered with the corresponding micro-CT images to verify whether the pulp tissue in the histological sections matched its counterpart in the Lugol-impregnated tissues identified in the micro-CT slices. RESULTS: There was no discernible effect on radiopacity when NaOCl was mixed with Lugol's solution. Tissue processing did not affect the time required for the complete dissolution of fresh bovine meat. Histological evaluation revealed a correlation between micro-CT and histological images confirming the identification of Lugol-impregnated pulp tissue in micro-CT images. CONCLUSIONS: The radiocontrast Lugol's solution was unaffected by NaOCl and did not interfere with its soft tissue dissolution capability. The impregnation protocol using Lugol's solution allowed the visualization of pulp tissue on the micro-CT images and the identification of pulp remnants after chemical-mechanical canal procedures.

Transcatheter Aortic Valve Replacement Without the Use of Contrast Medium: An Alternative Safe Implantation Technique.

BACKGROUND: New transcatheter equipment and accumulated experience have stimulated further refinements in implantation techniques. We aimed to compare the outcomes of transfemoral transcatheter aortic valve replacement (TF-TAVR) with and without the use of contrast medium (CM) in patients with glomerular filtration rate (GFR) <30 mL/min/1.73 m². METHODS: This single-center, retrospective study included all patients who underwent TF-TAVR procedure with Edwards Sapien balloon-expandable bioprostheses between September 2017 and September 2018 at the Zentralklinik Bad Berka Germany, and compared outcomes of TF-TAVR with and without the use of CM. RESULTS: A total of 98 consecutive patients were included in this study; 25 patients underwent TF-TAVR without the use of CM and 73 patients underwent TF-TAVR with the use of CM. Acute kidney injury was significantly higher in patients who received CM (15 patients [20.5%] in the control group vs 1 patient [4%] in the study group; P=.04). Other procedure-related complications were equally distributed between both groups. CONCLUSION: TF-TAVR without the use of CM can be considered a safe and reproducible alternative technique. Furthermore, it reduced the incidence of postoperative acute kidney injury in patients with GFR <30 mL/min/1.73 m².

Comparison of Penetration of Irrigant Activated by Traditional Methods with A Novel Technique.

INTRODUCTION: The effectiveness of irrigation depends upon various irrigation activation methods & devices used. AIM: To compare and evaluate the penetration of irrigant upto working length and into simulated lateral canals using four different irrigation activation techniques. MATERIALS AND METHODS: The root canals of 60 single-rooted teeth were instrumented using the proTaper rotary system. After decalcification of each sample tooth, three simulated lateral canals were created at 2mm, 4mm and 6mm levels from the root apex using a 06-size C+ file. After clearing the samples they were randomly assigned into four experimental groups (n=15) and 1ml of Irrigating Contrast Solution (ICS) was delivered into all samples and then it is activated with 4 different methods Group I-Conventional syringe and needle, Group II - Sonic activation with Endo activator, Group III - Ultrasonic activation with ultrasonic tips and Group IV - Activation using reciprocation movement. All the samples were examined under a stereomicroscope and irrigant penetration was evaluated by means of penetration of ICS. RESULTS: Group III and Group IV resulted in better penetration of ICS into lateral canals at 2mm and 4mm depth (p<0.001), when compared with Group I and II. At lateral canals 6mm all the groups except Group I, had shown 100 % penetration. CONCLUSION: The activation of irrigant using reciprocation was able to achieve penetration of irrigating contrast solution both up to the working length and into lateral canals. Hence the clinical significance of this method of irrigant activation is that it can be used for effective penetration of irrigants both upto working length and into lateral canals.