Biofilms are responsible for the most prevalent oral infections such as caries, periodontal disease, and pulp and periapical lesions, which affect the quality of life of people. Antibiotics have been widely used to treat these conditions as therapeutic and prophylactic compounds. However, due to the emergence of microbial resistance to antibiotics, there is an urgent need to develop and evaluate new antimicrobial agents. This scoping review offers an extensive and detailed synthesis of the potential role of selenium nanoparticles (SeNPs) in combating oral pathogens responsible for causing infectious diseases. A systematic search was conducted up until May 2022, encompassing the MEDLINE, Embase, Scopus, and Lilacs databases. We included studies focused on evaluating the antimicrobial efficacy of SeNPs on planktonic and biofilm forms and their side effects in in vitro studies. The selection process and data extraction were carried out by two researchers independently. A qualitative synthesis of the results was performed. A total of twenty-two articles were considered eligible for this scoping review. Most of the studies reported relevant antimicrobial efficacy against C. albicans, S. mutans, E. faecalis, and P. gingivalis, as well as effective antioxidant activity and limited toxicity. Further research is mandatory to critically assess the effectiveness of this alternative treatment in ex vivo and in vivo settings, with detailed information about SeNPs concentrations employed, their physicochemical properties, and the experimental conditions to provide enough evidence to address the construction and development of well-designed and safe protocols.

Several articles have used cone beam computed tomography (CBCT) to study the morphology of the maxillary molars and to ascertain its ability to visualize the second mesiobuccal canal (MB2); however, its geometric location has not been examined in depth. The aim of this study was to describe in vivo the prevalence and location of the MB2 in the mesiobuccal root of the first maxillary molar (1MM) and the second maxillary molar (2MM) through CBCT imaging. Five hundred fifty CBCT images of the 1MM and 550 of the 2MM were analyzed. To detect the MB2 canal, the observation and measurements were done 1 mm apically to the pulpal floor to standardize the methodology. The geometric location of the central point of the MB2 canal (PMB2) was measured in relation to the central point of the mesiobuccal canal (PMB1) and in relation to the line projected between the PMB1 and the central point of the palatal canals (PP). The data were analyzed using descriptive statistics, with a value of P < 0.05 being statistically significant. In the 1MM, the prevalence of the MB2 canal was 69.82% and was more frequent in women (p = 0.005). The distance between PMB1 and PP was 7.64 ± 1.04 mm. The average distance between PMB1 and PMB2 was 2.68 ± 0.49 mm, and for PMB2 and the line projected between the PMB1 and PP canals was 1.25 ± 0.34 mm. In the 2MM, the MB2 canal was identified in 46.91% and was more frequent in men (p = 0.000). The distance between PMB1 and PP was 7.02 ± 1.30. The average distance between PMB1 and PMB2 was 2.41 ± 0.64 mm, and for the PMB2 and the line projected between the PMB1 and PP canals was 0.98 ± 0.33 mm. The MB2 canal was found in a high percentage of the sample. These results indicate that CBCT is an effective, high-precision diagnostic tool not only for detecting but also locating in vivo the MB2 canal in the mesiobuccal root of upper molars.

Objective: To compare the antibacterial effectiveness of 0.5% sodium hypochlorite (NaOCl) activated by the Er,Cr:YSGG laser-activated irrigation (LAI) and passive ultrasonic irrigation (PUI) against a 10-day-old intracanal Enterococcus faecalis biofilm. Background: LAI and PUI are regarded as alternative methods to release the irrigant in the inner regions of the root canal system achieving enhanced cleaning ability. Nevertheless, little evidence regarding the activation of low concentrations of NaOCl has been reported. Materials and methods: Seventy-two single-rooted teeth were instrumented, inoculated ( E. faecalis ATCC 29212), and incubated for 10 days to allow biofilm formation. Specimens were randomly divided into six groups ( n = 12 each): (1) 0.5% NaOCl+Er,Cr:YSGG LAI, (2) saline+Er,Cr:YSGG LAI, (3) 0.5% NaOCl+PUI, (4) saline+PUI, (5) positive control (no treatment), and (6) negative control (no bacteria). The activation time was distributed as follows: 30 sec of activation, followed by a rest phase of 30 sec, and ending with 30 sec of activation. The number of bacterial survivors was determined by plate counting. Results: Both irrigation regimens LAI and PUI reduced the number of colony-forming unit. Moreover, LAI +0.5% NaOCl and the rest of groups significantly differ ( p < 0.001 for all comparisons). Conclusions: Er,Cr:YSGG LAI proved to be more effective than PUI in enhancing the antimicrobial activity of 0.5% NaOCl against 10-day-old intracanal E. faecalis biofilms.

The onset and persistence of endodontic infections due to residual biofilm after chemical disinfection promotes secondary bacterial infection. Alternative methods to disinfect operated root canals are a matter of great interest. The aim was to evaluate the antibacterial effectiveness of sodium hypochlorite (NaOCl) at low concentrations activated by the Er,Cr:YSGG laser-activated irrigation (LAI) against 10-day-old intracanal Enterococcus faecalis biofilm. Biofilms were formed inside the root canals and divided into 7 groups (n13): 0.5% NaOCl + Er,Cr:YSGG; Saline + Er,Cr:YSGG; 0.5% NaOCl + syringe irrigation(SI); 2.5% NaOCl + SI; 5% NaOCl + SI; positive and negative controls. Bacterial survivors were counted and specimens visualized under scanning electron and confocal laser scanning microscopy. Treatments with 0.5% NaOCl + Er,Cr:YSGG and 2.5% NaOCl + SI gave a significant reduction in the number of CFU/mm². Moreover, scanning electron microscopy and confocal laser scanning microscopy imaging confirmed and reinforced bacteriological data. Thus, Er,Cr:YSGG LAI proved to be able to improve the intracanal distribution of 0.5% NaOCl after 60 s of activation, reaching the same level of effectiveness than 2.5% NaOCl. This is regarded as of clinical interest, since working with lower concentrations may contribute to reduce undesired effects.