Endodontic Microflora of Different Teeth in the Same Mouth

International Journal of Applied Dental Sciences, 2021

Root canal system acts as an 'affluent sanctuary' for the growth and survival of endodontic microbiota. This is attributed to the special environment which the microbes get inside the root canals. Although variety of microbes such as viruses and fungi have been isolated from the root canal system, bacteria are the most commonly found to be associated with Endodontic infections. These are the first to reach the pulp and initiate the pulpal reaction through direct pulp exposure, lateral/accessory canals or through periodontal membrane and blood stream. The oral cavity is home to multiple anatomic micro niches which may vary from birth to old age due to changes in oral environment however root canal being the closed space harbours different microbiota including gram negative and positive microorganisms. To achieve the best results with root canal therapy it becomes important to have knowledge about the residing microbiota and how to combat them.

Since 1890, when Miller first observed microorganisms associated with pulp tissue, microorganisms have been implicated in infections of endodontic origin. Microbes seeking to establish in the root canal must leave the nutritionally rich and diverse environment of the oral cavity, breach enamel, invade dentine, overwhelm the immune response of the pulp and settle in the remaining necrotic tissue within the root canal. During that time they have to compete in a limited space with other microbes for the available nutrition. It is no accident that microbes berth in a particular environment there are ecological advantages for them to establish and flourish if conditions are favorable. This review will highlight the recent facts and controversies related to endodontics microbiology.

Journal of Endodontics, 2016

Introduction: The purpose of this study was to combine multiple displacement amplification 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 with 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 multiple displacement amplification, and the levels of 107 bacterial taxa were analyzed by checkerboard DNA-DNA hybridization. The taxa were divided into 3 distinct microbial populations depending on their mean proportion in samples (% DNA probe counts AE standard error of the mean) as follows: dominant ($3.0%), subdominant (>1.6%-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 AE 0.98), Porphyromonas gingivalis (5.42 AE 2.09), Streptococcus sobrinus (5.33 AE 0.69), and Stenotrophomonas maltophilia (4.72 AE 1.73). Among the subdominant population were Eubacterium saphenum (3.85 AE 1.06), Helicobacter pylori (3.16 AE 0.62), Dialister pneumosintes (3.12 AE 1.1), Clostridium difficile (2.74 AE 0.41), Enterobacter agglomerans (2.64 AE 0.54), Salmonella enterica (2.51 AE 0.52), Mobiluncus mulieris (2.44 AE 0.6), and Klebsiella oxytoca (2.32 AE 0.66). In the population of bacteria present at the lowest mean proportions (the residual population), Bacteroides ureolyticus (0.04 AE 0.01), Haemophilus influenzae (0.04 AE 0.02), and Prevotella oris (0.01 AE 0.01) were found at the lowest mean proportions. Enterococcus faecalis was detected in the residual population (0.52 AE 0.26). Conclusions: The microbial climax community in teeth refractory to endodontic treatment not only harbors medically important species but also contains distinct microbial consortia present with different population levels.

Oral Microbiology and Immunology, 2004

Dentistry Journal

The primary objective of endodontic therapy is to create a biologically acceptable environment within the root canal system that allows for the healing and maintenance of the health of the peri-radicular tissue. Bacteria are one of the main causes of pulp problems, and they have different methods of penetrating and invading the endodontic space such as through carious lesions, traumatic pulp exposures, and fractures. The types of bacteria found range from facultative anaerobes to aerobes, up to the most resistant species able to survive in nutrient-free environments; the bacterial species Enterococcus faecalis belongs to this last group. Enterococcus faecalis is considered one of the main causes of recurring apical periodontal lesions following endodontic treatment, with persistent lesions occurring even after re-treatment. The review presented in this paper was performed in accordance with the PRISMA protocol and covers articles from the related scientific literature that were sour...

Endodontic Topics, 2003

The science of oral microbiology is in a period of change from the era of bacterial cultivation to an era of molecular genetic methods and techniques. Already a significant body of new knowledge exists with regard to the oral flora in health and disease. Inevitably, this new knowledge has led to a better understanding of many oral diseases. In endodontics, the prevailing concepts are still to a great extent based on the results of the classical cultivation studies. However, a few groups have started to use molecular methods, and a new understanding of endodontic infections is presently evolving. Thus, the root canal infection clearly is more complex than revealed by cultivation methods alone, and both previously unidentified and uncultivable microorganisms have been detected by molecular methods. A reasonable estimate at present is that the infected root canal contains, not less than 10, but rather between 10 and 50 bacterial species which coincide well with the number of bacterial species normally found in a dental plaque sample and at different sites in the oral cavity. A further interesting finding in the studies using molecular techniques is that the microbiota of the infected root canal appears to be very similar to the flora of the periodontal pocket in patients with active periodontal disease. With regard to infection of periapical lesions in patients with asymptomatic apical periodontitis, electron microscopic and molecular methods have confirmed our cultivation findings that this is a common occurrence. Mature biofilms have been demonstrated on the external surfaces of root tips and in the form of sulfur granules within periapical granulomas. As in dental plaque, Actinomyces species appear to have a special role as scaffold builders in the development of sulfur granules. Other bacteria are then attracted to the site and a multibacterial granule (biofilm) develops. In addition, in situ hybridization studies show a variety of different bacteria and bacterial morphotypes in periapical lesions. With DNA-DNA hybridization between 11and 39 bacterial species have been recognized in the lesions, again confirming that in patients with active disease, the microbiotas of endodontic and periodontal infections are very similar. Thus, the recent findings demonstrate and confirm that the periapical endodontic lesion is not as hostile to microorganisms as many have thought. As clinicians we have to understand and accept that an infection might not be limited to the root of the tooth, but include the periapical lesion as well.

Journal of Endodontics, 2014

The aim of the present study was to analyze the microbiota of primary and secondary/ persistent endodontic infections of patients undergoing endodontic treatment with respect to clinical and radiographic findings. Methods: Samples from the root canals of 21 German patients were taken using 3 sequential sterile paper points. In the case of a root canal filling, gutta-percha was removed with sterile files, and samples were taken using sterile paper points. The samples were plated, and microorganisms were then isolated and identified morphologically by biochemical analysis and sequencing the 16S rRNA genes of isolated microorganisms. Results: In 12 of 21 root canals, 33 different species could be isolated. Six (50%) of the cases with isolated microorganisms were primary, and 6 (50%) cases were endodontic infections associated with root-filled teeth. Twelve of the isolated species were facultative anaerobic and 21 obligate anaerobic. Monomicrobial infections were found for Enterococcus faecalis and Actinomyces viscosus. E. faecalis was most frequently isolated in secondary endodontic infections (33%). Moraxella osloensis was isolated from a secondary endodontic infection that had an insufficient root canal filling accompanied by a mild sensation of pain. A new bacterial composition compromising Atopobium rimae, Anaerococcus prevotii, Pseudoramibacter alactolyticus, Dialister invisus, and Fusobacterium nucleatum was recovered from teeth with chronic apical abscesses. Conclusions: New bacterial combinations were found and correlated to clinical and radiographic findings, particularly to chronic apical abscesses. M. osloensis was detected in root canals for the second time and only in German patients. (J Endod 2014;40:670-677)

African Journal of Microbiology Research, 2013

This study investigated the microbial species present in necrotic pulps of permanent teeth needing endodontic treatment. The search for articles was conducted on the Health Science Database and considered all articles published until October 2011, with selected human clinical studies examined, through molecular biology the microorganisms that are present in root canals of permanent teeth requiring root canal treatment with necrosis pulps (exposition). The selected articles were categorized according to the methodological quality and evidence in levels A (high), B (moderate), and C (low). The search strategy was based on PubMed, Bireme, Cochrane and OVID databases. The data extracted from the studies were also tabulated. Eighty-four titles and abstracts were assessed and eight articles met the inclusion criteria, showing that there is a high diversity of microorganisms involved in necrotic permanent teeth. The microorganisms found in these articles were: Porphyromonas gingivalis (27.8%), Porphyromonas endodontalis (42.6%), Prevotella intermedia (5.6%), Prevotella nigrescens (7.4%), Bacteroides forsythus (21%) and Enterococcus faecalis (>50%). This systematic review found high evidence of the polymicrobial nature of primary endodontic infections in necrotic permanent teeth, and also showed that there is a dominance of anaerobic bacteria.

Journal of Endodontics, 2008

The aim of this study was to evaluate the composition of the microbiota of primary endodontic infections associated with symptomatic teeth. Samples were collected by means of a #15 H-type file and 2 sterile paper points from 60 symptomatic (n ϭ 30) or asymptomatic (n ϭ 30) single-rooted teeth with necrotic pulp. The presence of 40 bacterial species was determined by the checkerboard DNA-DNA hybridization method. The species found in higher counts (ϫ10 5 ) in symptomatic cases were Fusobacterium nucleatum ssp. vincentii, Veillonella parvula, Treponema socranskii, Enterococcus faecalis, and Campylobacter gracilis and in asymptomatic cases were F. nucleatum ssp. vincentii, Fusobacterium nucleatum ssp. nucleatum, E. faecalis, Eubacterium saburreum, and Neisseria mucosa. Total bacterial counts and counts of Tannerella forsythia were significant higher in symptomatic cases (p Ͻ 0.05), whereas levels of Propionibacterium acnes were reduced in this group of teeth. The data of the present investigation suggested an association between higher total bacterial counts and levels of T. forsythia and the presence of pain. (J Endod 2008;34:541-545)

Australian Endodontic Journal, 1998

Objective. The purposes of this study were to determine what microbial flora were present in teeth after failed root canal therapy and to establish the outcome of conservative re-treatment.