Addition of MTA in a salicylate-based resin root canal sealer to retrograde root-end filling

Aim To evaluate the flow, pH and calcium release of white MTA (WMTA), salicylate-based resin root canal sealer (Sealapex; SEAL) and SEAL containing 10 (SE10) or 20% (SE20) (w/w) of MTA. Methodology Flow test was realized according to ISO 6876 specification. The sealers samples (n= 10) were placed in polyethylene tubes and immersed in deionized water. After 24 hours and 7, 14, and 28 days, the water pH was determined with a pH meter, and calcium release was assessed by atomic absorption spectrophotometry. Results SEAL and WMTA showed respectively the highest and lowest flow rate when compared with the other materials (P<0.05). SE20 showed the highest pH value only in 24h and 7 days periods (p<0.05). In 14- and 28-days periods, SEAL showed the lowest pH value (p<0.05), but there are no differences between other groups (p>0.05). In all periods, WMTA and SEAL respectively showed the highest and lowest calcium release (p<0.05). Conclusions SE20 proves to be an association with better flow and handling than WMTA, with satisfactory potential for alkalinization and calcium release.

Effects of dentinary contamination by endodontic irrigants on bonding strength of adhesive systems

This study aimed to evaluate if 2.5% sodium hypochlorite compromises the adhesion of bonding materials. The factors in the study were the irrigation solutions in two levels: 2.5% sodium hypochlorite and saline solution; and the adhesive systems used in three levels: three-step adhesive, universal adhesive, and two-step self-etch adhesive systems. The answer variable used was the microshear bond strength obtained through a universal testing machine and fracture mode. Six groups were obtained (n=10) : Etch-and-rinse/Saline (saline solution + 3-step adhesive system - Scotchbond Multipurpose, 3M ESPE); Universal/saline (saline solution + universal adhesive system ­ Prime&Bond,); Self-etch/saline (saline solution + 2-step self-etch adhesive systems - Clearfil SE Bond); Etch-and-rinse/Hypo (sodium hypochlorite 2,5% + 3-step adhesive system - Scotchbond Multiuso); Universal/Hypo (sodium hypochlorite 2,5% + universal adhesive system ­ Prime&Bond); Self-etch/Hypo (sodium hypochlorite 2,5% + 2-step self-etch adhesive system - Clearfil Se Bond). The specimens were obtained from 60 healthy bovine incisors. The crowns were separated from the roots, and the regularization of the buccal surface was performed. The groups received saline solution and 2.5% sodium hypochlorite for 30 minutes, respectively. A matrix of 1mm and 3mm oh height was stabilized by Scotch tape to obtain the resin sticks. Afterward, the bond strength test was performed in a universal testing machine at 1mm/min speed. The data were analyzed with normality Shapiro-Wilk, two-way ANOVA, and Tukey's tests (p<0.001). Etch-and-rinse and Self-etch adhesives presented the highest bond strength values after irrigation with saline solution and 2.5% sodium hypochlorite, respectively (P < 0.01). The irrigation with 2.5% sodium hypochlorite decreased the bond strength values of Etch-and-rinse and Universal (P < 0.01). On the other hand, 2.5% sodium hypochlorite improved the bond strength values of Self-etch (P < 0.01). In conclusion, 2.5% sodium hypochlorite negatively impacted the bond strength of Etch-and-rinse and Universal but improved the adhesion of Self-etch.

Passive ultrasonic irrigation in calcium hydroxide removal from root canals: a sem/ eds analysis

AIM: The aim of this study was to evaluate the efficacy of different lengths of time of passive ultrasonic irrigation (PUI) in removing calcium hydroxide (CH) paste from root canal, using scanning electron microscopy and energy dispersive spectrometry (SEM/EDS). MATERIAL AND METHODS: Fifty-four human premolars were used. After coronal access, a size #15 K-file was used to obtain apical patency. Root canal preparation was performed using WaveOne 40.08 instruments. CH paste was placed into the root canal. Specimens were stored in a humid environment, and after seven days, they were divided into five groups (n=12) according to the irrigation protocols: Manual­ a size #40 K-file; PUI/1­ 1 min; PUI/2­ 2 min; PUI/3­ 3 min; and Control­ without CH paste. An elementary chemical microanalysis (SEM/EDS) was performed to quantify the presence of calcium on the dentinal walls. RESULTS: The percentage of calcium was higher in all experimental groups when compared to the control group (P < 0.05); but no differences among them were found (P > 0.05). CONCLUSION: The amount of calcium hydroxide paste on the dentinal walls was not dependent on length of time of ultrasonic activation. SEM/EDS analysis seems to be a reliable method to assess CH paste removal from the root canals.

Evaluation of the in vitro antimicrobial activity of alcoholic solution and aqueous extract of bee propolis against enterococcus faecalis

AIM: The purpose of this study was to analyze the in vitro antimicrobial activity of aqueous and alcoholic extracts of propolis at 1% and 3% concentrations against Enterococcus faecalis (ATCC® 19433). MATERIAL AND METHODS: Initially, the microbial suspension was seeded in a Brain Heart Infusion Agar (BHIA) culture medium, distributed in 20 Petri dishes. Then, 4 soaked filter paper discs were placed on the surface of the inoculated medium of each plate for 1 minute in 1 mL of the following substances: C+ (positive control, n=20): 2% chlorhexidine gel; C- (negative control, n=20): saline solution; S1 (n=10): 1% bee propolis alcoholic solution; S2 (n=10): 3% bee propolis alcoholic solution; E1 (n=10): 1% aqueous propolis extract; E2 (n=10): 3% aqueous propolis extract. One filter paper disc of each (C+, C-, S1 and S2) was placed in a set of 10 Petri dishes, whereas one filter paper disc of each (C+, C-, E1 and E2) was placed in the other set of 10 Petri dishes. RESULTS: The results obtained after incubation at 37°C for 24 hours under microaerobic conditions revealed that S2 showed higher mean levels of microbial growth inhibition as compared to E1, E2 and S1. There were no significantly statically differences between the groups, except for the S2 group and C- group. Mean levels in all other groups were lower than in the C+ group. CONCLUSION: The study concluded that 1% and 3% bee propolis alcoholic solution had lower antibacterial activity against Enterococcus faecalis as compared to 2% chlorhexidine gel.