Microbial Ecosystem Analysis in Root Canal Infections Refractory to Endodontic Treatment

Introduction To combine Multiple Displacement Amplification (MDA) and checkerboard DNA–DNA hybridization to qualitatively and quantitatively evaluate the microbiota present in infections refractory to endodontic treatment. Methods The subjects of this study were 40 patients presenting periapical lesions refractory to endodontic treatment. Samples were taken by scraping or filing root canal walls with a #10 K-type hand file. Sample DNA was amplified by MDA, and the levels of 107 bacterial taxa were analyzed by checkerboard DNA–DNA hybridization. The taxa were divided into three distinct microbial populations, depending on their mean proportion in samples (% DNA probe counts ± SEM), as follows: dominant (≥3.0%), sub-dominant (\u3e1.6 to 3.0%) and residual (≤1.6%) populations. The significance of differences was determined using the Mann-Whitney test. Results The taxa present with the highest mean proportions (constituting the dominant population) were Corynebacterium diphtheriae (8.03±0.98), Porphyromonas gingivalis (5.42±2.09), Streptococcus sobrinus (5.33±0.69), and Stenotrophomonas maltophilia (4.72±1.73). Among the sub-dominant population were Eubacterium saphenum (3.85±1.06), Helicobacter pylori (3.16±0.62), Dialister pneumosintes (3.12±1.1), Clostridium difficile (2.74±0.41), Enterobacter agglomerans (2.64±0.54), Salmonella enterica (2.51±0.52), Mobiluncus mulieris (2.44±0.6), and Klebsiella oxytoca (2.32±0.66). In the population of bacteria present at the lowest mean proportions (the residual population), Bacteroides ureolyticus (0.04±0.01), Haemophilus influenzae (0.04±0.02), and Prevotella oris (0.01±0.01) were found at the lowest mean proportions. Enterococcus faecalis was detected in the residual population (0.52±0.26). Conclusion The microbial climax community in teeth refractory to endodontic treatment not only harbor medically important species, but also contains distinct microbial consortia present with different population levels

Antimicrobial agents used in the control of periodontal biofilms: effective adjuncts to mechanical plaque control?

The control of biofilm accumulation on teeth has been the cornerstone of periodontal disease prevention for decades. However, the widespread prevalence of gingivitis suggests the inefficiency of self-performed mechanical plaque control in preventing gingival inflammation. This is particularly relevant in light of recent evidence suggesting that long standing gingivitis increases the risk of loss of attachment and that prevention of gingival inflammation might reduce the prevalence of mild to moderate periodontitis. Several antimicrobials have been tested as adjuncts to mechanical plaque control in order to improve the results obtained with oral home care. Recent studies, including meta-analyses, have indicated that home care products containing chemical antimicrobials can provide gingivitis reduction beyond what can be accomplished with brushing and flossing. Particularly, formulations containing chlorhexidine, mouthrinses containing essential oils and triclosan/copolymer dentifrices have well documented clinical antiplaque and antigingivitis effects. In vivo microbiological tests have demonstrated the ability of these antimicrobial agents to penetrate the biofilm mass and to kill bacteria growing within biofilms. In addition, chemical antimicrobials can reach difficult-to-clean areas such as interproximal surfaces and can also impact the growth of biofilms on soft tissue. These agents have a positive track record of safety and their use does not seem to increase the levels of resistant species. Further, no study has been able to establish a correlation between mouthrinses containing alcohol and oral cancer. In summary, the adjunct use of chemical plaque control should be recommended to subjects with well documented difficulties in achieving proper biofilm control using only mechanical means

Alteração no volume do fluido gengival durante a retração de caninos superiores Change in the gingival fluid volume during maxillary canine retraction

INTRODUÇÃO: na análise da teoria da pressão/tensão do movimento dentário, a aplicação de uma força ortodôntica causa um deslocamento gradual dos fluidos do ligamento periodontal, acompanhado pela distorção das células e da matriz extracelular. OBJETIVOS: avaliar a quantidade de volume do fluido gengival (FG) nas faces mesiais e distais dos caninos superiores, de 14 pacientes (3 homens e 11 mulheres) submetidos a movimentação ortodôntica. MÉTODOS: o fluido foi coletado com tira de papel absorvente padrão (Periopaper®) e seu volume foi determinado por meio da utilização do medidor Periotron®, em sete tempos distintos (dia -7, dia 0, 1 hora, 24 horas, 14 dias, 21 dias e 80 dias). O teste Friedman foi usado para comparar os dados obtidos (p INTRODUCTION: In the analysis of the pressure-tension theory of tooth movement, the application of an orthodontic force causes gradual displacement of fluids of the periodontal ligament, followed by distortion of the cells and extracellular matrix. OBJECTIVES: This study evaluated the gingival fluid volume on the mesial and distal aspects of the maxillary canines of 14 patients (3 males and 11 females) submitted to orthodontic movement. METHODS: The fluid was collected using standard absorbent paper strips (Periopaper&trade;) and the fluid volume was determined using the instrument Periotron&trade; at seven different periods (day -7, day 0, 1 hour, 24 hours, 14 days, 21 days, 80 days). The Friedman test was applied to compare the data achieved (p < 0.01 and p < 0.05). RESULTS: The results revealed a significant change in the gingival fluid volume with time on both the pressure side (p < 0.001) and the tension side (p < 0.01). On the pressure side, the gingival fluid volume was significantly lower at the periods 0 (p < 0.01) and 24hs (p < 0.001) compared to the period 80 days