Activiteit

48). However, significant decrease of baseline mean VAS pain score of the participants in both groups was found during access cavity preparation or initial file insertion (P<0.05).

Mixed Li-KT solution did not increase the success rate of IANB injection significantly.

Mixed Li-KT solution did not increase the success rate of IANB injection significantly.

The present clinical study investigated the microbiota of teeth with persistent secondary endodontic infection in the different phases of root canal retreatment.

Twenty filled single-rooted teeth with apical periodontitis were included. Samples were collected with sterile paper points before chemo-mechanical preparation (CMP) (S1), after CMP (S2) and after 30 days of calcium hydroxide-based intracanal medication (ICM) (S3). Cultivable bacteria were assessed by colony forming units count (CFU/mL). DNA was extracted and assessed by using nested PCR. Paired t-test and repeated measures ANOVA were applied for intragroup analysis in the stages of endodontic therapy at a significance level of 5%.

Cultivable bacteria were detected in all initial samples. CMP reduced bacteria by 99.4% and ICM by 99.5%. The most prevalent species found in the initial samples were E. faecalis (20/20), P. gingivalis (20/20), F. nucleatum (17/20) and A. actinomycetemcomitans (10/20), whereas D. pneumosintes, F. alocis, P. nigrescenlus and cocci, facultative and strict anaerobes. E. faecalis and P. gingivalis were frequently detected in all stages of root canal retreatment, evidencing their great resistance to endodontic procedures. The endodontic procedures were effective in reducing the levels of bacteria from teeth presenting with persistent/secondary endodontic infection.

To assess the effect of osmotic stress on various bacteria in a planktonic milieu and the effect of exposure to sodium hypochlorite (NaOCl) on the microbial cells previously subjected to osmotic stress.

Enterococcus faecalis, Streptococcus sanguinis, Fusobacterium nucleatum, Porphyromonas gingivalis and Prevotella intermedia were suspended as follows Iso-osmotic group 0.9% NaCl; Hypo-osmotic group “ultrapure water”; Hyper-osmotic group 9% NaCl solution for 120 hours before exposure to 0.0001% NaOCl for 10 minutes. Quantitative analyses of viable cells were performed at 0 and 120 hours and after exposure to NaOCl to obtain colony forming units (CFU/mL). A linear mixed-effects model was used to find the association between mean CFU/mL (logarithmic transformation) and the interaction of solution Group and Time (P<0.001).

F. nucleatum, P. gingivalis and P. intermedia did not survive after 24 hours in any of the solutions and were excluded from further testing. For S. sanguinis there were significant diffiated with lower viable bacterial numbers, when compared to the other media for the above species. Hyper-osmotic stress was associated with higher viable bacterial numbers after NaOCl exposure for E. faecalis.

S. sanguinis and E. faecalis were able to withstand osmotic stress for 120 hours. Hypo-osmotic stress before contact with NaOCl was associated with lower viable bacterial numbers, when compared to the other media for the above species. Hyper-osmotic stress was associated with higher viable bacterial numbers after NaOCl exposure for E. faecalis.

The purpose of this in vitro study was to compare the quality of root canal filling of C Point, GuttaCore and lateral compaction using confocal laser scanning microscopy.

Ninety recently extracted human mandibular incisors with single canal were selected. Canals were prepared with ProTaper instruments to size F3 and obturated using C Point, GuttaCore or lateral compaction technique. Endosequence BC sealer was labeled with Rhodamine B dye to allow analysis under a confocal microscope. The percentages of gutta-percha filled area (PGFA), sealer filled area (PSFA), voids (POV) and interfacial adaptation (IA) was assessed at 2, 5 and 8 mm from the apex, using image analysis software. Kruskal-Wallis followed by Mann Whitney U tests were used for data analysis, and the P value was set at 0.05 (P=0.05).

No significant difference was seen among the three groups at 2 mm level for PGFA, PSFA and voids (P>0.05). MEK inhibition At 5 and 8 mm levels, canals filled with GuttaCore had significantly higher PGFA and lower PSFA than lateral compaction and C Point. Highest POV was seen for lateral compaction group followed by C Point and GuttaCore.

Out of the three techniques examined, best results in terms of quality of root canal filling were observed for GuttaCore. C Point system was found to be associated with internal defects such as tears and delamination which may adversely affect the long term performance of this system.

Out of the three techniques examined, best results in terms of quality of root canal filling were observed for GuttaCore. C Point system was found to be associated with internal defects such as tears and delamination which may adversely affect the long term performance of this system.

The aim of this study was to evaluate the cyclic fatigue, torsional behavior and bending resistance of EdgeTaper Platinum [ETP (tip 25, taper 0.06)], Flex Gold [FG (tip 25, taper 0.08)], Pro-T [PT (tip 25, taper 0.08)] and ProTaper Gold [PTG (tip 25, taper 0.08)] systems.

Rotary instruments of ETP, PT, FG, and PTG were used (n=30). Cyclic fatigue tests were performed using an artificial stainless-steel canal with a 60o angle and a 5-mm radius of curvature at body temperature (35°±1°C). The time and number of cycles to fracture (NCF) was recorded. The torsional test evaluated the torque and angle of rotation to failure at 3 mm from the tip according to ISO 3630-1. The fractured surface of each fragment was observed by using scanning electron microscopy (SEM). The bending test evaluated the torque required to bend the instruments at an angular deflection of 60°. Data were analyzed using one-way ANOVA and Tukey tests, and the level of significance was set at 5%.

The ETP had highest time until fracture and NCF than all the groups (P<0.05). The PTG had the highest torsional strength, followed by FG (P<0.05). The ETP had the highest angular rotation, followed by PT and PTG (P<0.05). The FG showed the highest bending resistance, followed by the PTG (P<0.05).

In conclusion, the ETP and PT exhibited higher cyclic fatigue resistance, higher angular deflection values and lower bending force than FG and PTG. The PTG instruments showed the highest torsional strength and the lowest cyclic fatigue resistance.

In conclusion, the ETP and PT exhibited higher cyclic fatigue resistance, higher angular deflection values and lower bending force than FG and PTG. The PTG instruments showed the highest torsional strength and the lowest cyclic fatigue resistance.