RESUMO
It has been proposed that oral commensal bacteria are potential reservoirs of a wide variety of antimicrobial resistance genes (ARGs) and could be the source of pathogenic bacteria; however, there is scarce information regarding this. In this study, three common streptococci of the mitis group (S. oralis, S. sanguinis, and S. gordonii) isolated from dental plaque (DP) were screened to identify if they were frequent reservoirs of specific ARGs (blaTEM, cfxA, tetM, tetW, tetQ, ermA, ermB, and ermC). DP samples were collected from 80 adults; one part of the sample was cultured, and from the other part DNA was obtained for first screening of the three streptococci species and the ARGs of interest. Selected samples were plated and colonies were selected for molecular identification. Thirty identified species were screened for the presence of the ARGs. From those selected, all of the S. sanguinis and S. oralis carried at least three, while only 30% of S. gordonii strains carried three or more. The most prevalent were tetM in 73%, and blaTEM and tetW both in 66.6%. On the other hand, ermA and cfxA were not present. Oral streptococci from the mitis group could be considered frequent reservoirs of specifically tetM, blaTEM, and tetW. In contrast, these three species appear not to be reservoirs of ermA and cfxA.
RESUMO
The antibacterial efficacy of antimicrobial filling pastes (AFP) used in the root canal treatment of primary teeth has been widely reported. However, antibiotic resistance as an emerging global problem could impact their current efficacy. This study aimed to evaluate the efficacy of two common AFP on susceptible or resistant bacteria isolated from primary necrotic molars. Microbiological samples were obtained and cultured from the root canals of 34 children. In total, 96 colony-forming units were obtained to determine their resistance to tetracycline, rifampicin, and chloramphenicol. They were identified as S. mutans or E. faecalis using polymerase chain reaction. The antimicrobial activity of CTZ paste (chloramphenicol, tetracycline, zinc oxide, and eugenol) and Guedes-Pinto modified (GPM) paste (rifampicin, prednisolone, iodoform, and camphorated paramonochlorophenol) were tested against the identified and selected microorganisms. Larger size inhibition zones were observed in both species when the tested strains were susceptible to the antibiotics in the AFP preparation. The efficacy of AFP containing antibiotics depends on the antibiotic resistance profile of the strain. Antibiotic resistance and its effect on the AFP were shown, which calls into question the use of simplified endodontic techniques that depend on antibiotics, since in these cases these techniques could not clinically eliminate resistant bacteria from the root canal.
RESUMO
La colocación de restauraciones directas a base de resina en el área de premolares y molares permite realizar tratamientos complejos en pacientes afectados por atrición dental severa y/o bruxismo. Hoy en día gracias a la técnica de grabado ácido, la fuerza de adhesión de la resina al esmalte disminuye la microfi ltración y sensibilidad postoperatoria. El objetivo de este artículo es describir la rehabilitación provisional mediante restauraciones adhesivas de resina compuesta en un paciente con atrición dental severa, el cual recibirá posteriormente tratamiento de ortodoncia por discrepancia de las arcadas. Al término de este tratamiento se colocarán restauraciones onlay de disilicato de litio (AU)
The placement of resin-based direct restorations in the area of premolars and molars allows the treatment of complex cases in patients aff ected by dental attrition and/or bruxism. Nowadays, due to the acid etching technique, the bond strength of the resin to the enamel will reduce the micro-leakage and post-operative sensitivity. The aim of this article is to describe the provisional rehabilitation with resin adhesive restorations, in a patient with a severe dental attrition, which will receive orthodontic treatment due to discrepancies in the arches. At the end of this treatment, ceramic restorations will be placed (AU)