Search

This in vitro study aims to evaluate the bacterial microleakage of three conometric connections. Sixty dental implants (3P implafavourite Scalenghe) were divided in groups (n = 20): Cone–Morse with passing screw (Group 1); Cone–Morse with solid abutment (Group 2); and Conometric connection with esthetic abutment (Group 3). The implants were fixed in resin bases. Then, 1.0 µL of Streptococcus oralis (SO) was inoculated in the internal platform in 10 fixtures for each group, and another 10 were inoculated with Pseudomonas aeruginosa (PA). The abutments were then screwed, and five implants from each subgroup were randomly selected for SEM inspection to ensure that the abutments were installed correctly. Data were submitted to statistical analysis, ANOVA and Fisher’s Least Significant Difference (p ≤ 0.05). The turbidity of the broth was monitored for 14 days of follow-up in order to determine the penetration of the bacterial suspension into the surrounding solution, but the observation of the samples lasted until the 90th day, in which there was no difference between the two. Microbial contamination was found in 30%, 20%, and 50% of Group 1, Group 2, and Group 3, respectively, but there were no statistically significant differences between the groups, and PA showed greater infiltration than SO. Although no statistically significant differences were found, cone morse connections showed lower infiltration percentages, respective to the conometric connection with 18° angle.

Background: In this ex vivo study, the aim was to evaluate the effects of ALAD and red light on Enterococcus faecalis in infected root canals using a special intracanal fiber. Methods: A total of 70 extracted, single-rooted teeth were used. The teeth were decoronated at the length of the roots to approximately 15 mm and then instrumented. The apical foramen was sealed by composite resin, and the root canals were infected with a pure culture of E. faecalis ATCC 29212 for eight days at 37 °C. Following the contamination period, the roots were divided into seven groups, including the positive and negative control groups, and treated as follows: ALAD 45 min; red light activation 7 min; ALAD 45 min and red-light activation 7 min; sodium hypochlorite 2.5% 15 min; sodium hypochlorite 1% 15 min. The samples were taken by three sterile paper points, transferred to tubes containing 1 mL of PBS, and immediately processed for the number of colony-forming units and the cell viability by using live/dead. Results: The best treatment is obtained with 2.5% NaOCl. Except for ALAD + red light vs. 1% NaOCl, a statistically significant difference is recorded for all treatments. The combination of 2.5% NaOCl and ALAD + 7 min irradiation produces an evident killing effect on the E. faecalis cells. On the other hand, 1% NaOCl is ineffective for the viability action, with 25% of dead cells stained in red. Conclusions: This ex vivo study shows that ALAD gel with light irradiation is an efficacious protocol that exerts a potent antibacterial activity against E. faecalis in infected root canals.

The present study aims to discuss the main factors involving the use of 5-aminolevulinic acid together with red LED light and its application in endodontic treatment through a narrative review and a case report. Persistence of microorganisms remaining on chemical-mechanical preparation or intracanal dressing is reported as the leading cause of failure in endodontics. Photodynamic therapy has become a promising antimicrobial strategy as an aid to endodontic treatment. Being easy and quick to apply, it can be used both in a single session and in several sessions, as well as not allowing forms of microbial resistance. 5-aminolevulinic acid in combination with red LED light has recently been studied in many branches of medicine, with good results against numerous types of bacteria including Enterococuss faecalis. The case report showed how bacterial count of CFU decreased by half (210 CFU/mL), after 45 min of irrigation with a gel containing 5% of 5-aminolevulinic acid compared to the sample before irrigation (420 CFU/mL). The subsequent irradiation of red LED light for 7 min, the bacterial count was equal to 0. Thus, it is concluded that the use of 5-aminolevulinic acid together with red LED light is effective in endodontic treatment.