Can the Enterococcus faecalis identified in the root canals of primary teeth be a cause of failure of endodontic treatment?

The Contribution of Various In Vitro Methodologies to Comprehending the Filling Ability of Root Canal Pastes in Primary Teeth

A void-free obturation during root canal treatment on primary teeth is currently very difficult to attain. In this study, the pulpectomy filling abilities of Bio-C Pulpecto (Angelus, Basil, Londrina, Paraná, Brazil) and of zinc oxide eugenol, or "ZOE" (DenPro, Prevest, New York, NY, USA), were compared using several in vitro techniques. Therefore, 30 primary anterior teeth were used in the present in vitro study. Analysis of variance (ANOVA), including a multiple comparison procedure (Holm-Sidak method, Dunn's Method, or Tukey test), was used. On micro-CT, Bio-C Pulpecto exhibited higher void percentages than did ZOE (10.3 ± 3.8%, and 3.5 ± 1.3%), respectively (p < 0.05). With digital microscopy, higher total void percentages were found in the BC (13.2 ± 26.7%) group compared to the ZOE (2.7 ± 2.8%) group (p < 0.05). With the CLSM, mean tubular penetration depths were higher for Bio-C Pulpecto than for ZOE in all canal thirds (p < 0.05). SEM images demonstrated no tags into dentinal tubules in either group throughout the three thirds. Moreover, higher statistically significant flowability was found for Bio-C (2.657 ± 0.06 mm) compared to ZOE (1.8 ± 0.13 mm) (p < 0.05). The findings of this study indicate that neither ZOE nor Bio-C Pulpecto appears to meet the criteria for an ideal root canal filling paste for primary teeth. This study laid the groundwork for future research by determining how micro-CT, digital microscopy, SEM, and CLSM contribute to our understanding of the filling process of primary teeth. More thorough research on the mechanism of root canal obturation on primary teeth is required to achieve a long-term successful root canal therapy in young children.

Bacteria associated with apical periodontitis promotes in vitro the differentiation of macrophages to osteoclasts

OBJECTIVE

To analyze the possible in vitro effect of the cytokine RANKL and bacteria involved in apical periodontitis on the differentiation of macrophages into osteoclasts.

MATERIAL AND METHODS

Bacteria were isolated (mainly E. faecium and E. faecalis) from the root canal of fifty patients with apical periodontitis, the possible effect of these bacteria on the phagocytic activity of the monocyte cell line THP-1 was analyzed by flow cytometry. Furthermore, the effect of these bacteria (alone or in combination with the cytokine RANKL) on the differentiation of THP-1 macrophages into osteoclasts was analyzed through the expression of the receptor RANK and the tartrate-resistant acid phosphatase TRAP. Finally, the release of different cytokines (IL-1β, TNF-α, IL-6, IL-8, IL-10, and IL-12p70) by THP-1 cells induced to differentiate into osteoclasts was also analyzed.

RESULTS

We observed a significant proportion of THP-1 cells were able to internalize E. faecium and E. faecalis. Furthermore, these bacteria were able to induce (alone or in combination with RANKL) a significant expression of RANK by THP-1 macrophages; accordingly, E. faecium and E. faecalis induced very significant levels of TRAP in these cells. Finally, during the differentiation of THP-1 macrophages induced by RANKL or bacteria, a significant release of the pro-inflammatory cytokines IL-6 and TNF-α was observed.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data suggest that the causative agents of apical periodontitis can induce the differentiation of osteoclasts as well as the release of pro-inflammatory cytokines, phenomena that may have an important role in the bone damage observed in this condition.

Physicochemical and Antibacterial Properties of Conventional and Two Premixed Root Canal Filling Materials in Primary Teeth

In this study, some physicochemical and antibacterial properties of three root canal filling materials for primary teeth, Calplus “CP” (Prevest DenPro, Lewes, DE, USA), Bio-C Pulpecto “Bio-CP” (Angelus, Basil, Londrina, Paraná, Brazil), and Zinc Oxide and Eugenol “ZOE” (Prevest DenPro, Lewes, DE, USA) were compared. For each material, the pH, solubility, contact angle, and crystalline microstructure under SEM were evaluated. Their antibacterial activity against Enterococcus faecalis was determined through direct tests. The Kruskal−Wallis test was used to analyze the results using a one-way analysis of variance on ranks. All the materials had an alkaline pH at 3, 24, and 72 h, with CalPlus having the highest (p < 0.05). Bio-CP was more soluble during the evaluation period (24 h) than ZOE and CalPlus (p < 0.05). Bio-CP and ZOE demonstrated the creation of crystallite structures on their surfaces after immersion in PBS at 37 °C, whereas CalPlus showed none. The lowest contact angle was observed for Bio-CP (53 ± 1.5°); contact angles of (86 ± 4°) and (96 ± 1°), respectively, were observed after 10 s of the deposition of the water drop for CalPlus and ZOE. In conclusion, according to this study, there is still a need to develop new filling materials for primary teeth. ZOE, CalPlus and Bio-CP demonstrated different physicochemical and antibacterial properties, but none of the materials had optimal properties and could be considered the most suitable filling material for primary teeth pulpectomy. Bioceramics in their current state are not an alternative. The physicochemical and antibacterial properties still need improvement to fit the intricate anatomy of primary teeth.

Virulence of Lactobacillus spp. misidentified as Enterococcus faecalis from children's carious dentine

Objective: This study aimed to search for Enterococcus faecalis in children's deep carious dentine and characterize their virulence traits.Material and Methods: Eight isolates from 15 carious molars identified by 16S rDNA species-specific PCR as E. faecalis were included. These eight isolates were subject to identification by MALDI-TOF and characterized regarding: (i) bacterial aggregation and biofilm formation on polystyrene and glass, with/without saliva, as single or dual-species (associated to Streptococcus mutans); (ii) environmental pH measurement before and after 24 h incubation; (iii) acidogenicity; (iv) gelatinase production; (v) macrophage adherence; and (vi) toxicity towards Caenorhabditis elegans. Statistical analyses were performed using two-way ANOVA/Tukey or Fisher's exact tests.Results: All isolates initially identified as E. faecalis by PCR were correctly identified as Lactobacillus by MALDI-TOF, being designated as Lactobacillus misidentified as Enterococcus (LME). These isolates produced biofilm in the presence of saliva and in the dual-species assays. Bacterial aggregation was only observed in the dual-species model. After 24 h, environmental pH dropped from 7.5 to 4.5 for seven of eight isolates, and to 4.0 in all dual-species models. LME isolates were acidogenic, none of them produced gelatinase or adhered to macrophages, but all presented toxicity towards C. elegans.Conclusions: No E. faecalis were identified in the children's caries lesions. All LME isolates presented important virulence traits, including biofilm formation and high acidogenicity, which cause enamel demineralization, that might increase the risk of dental caries in children carrying LME. Thus, the correct identification and in-depth virulence characterization of microorganisms isolated from dental caries are important to understand the dynamics of this disease.

A retrospective study on the long-term outcomes of pulpectomy and influencing factors in primary teeth

Background/purpose

Materials and methods

Results

Conclusion

Radiographic and antimicrobial evaluation of enterococcus Faecalis and Actinomyces Israelii micro-organisms after photodynamic therapy (aPDT)

This study evaluated the action of Antimicrobial Photodynamic Therapy (aPDT) on Enterococcus faecalis and Actinomyces israelii. Samples were taken from the root canal system, at different stages of treatment and bacteria were identified through qPCR. Fifty teeth (incisors, canines, and premolars) with pulp necrosis and periapical lesion diagnosis were randomly selected and divided into 2 groups: Group 1 (G1) - Endodontic Therapy with Mechanical Chemical Preparation (MPQ) and intracanal medication; Group 2 (G2) - Endodontic therapy with MPQ, intracanal medication, and 2 applications of aPDT. APDT was performed with application of 0.005% methylene blue, wavelength of 660 nm, and 90 seconds. Follow-up was performed with an initial x-ray and an x-ray 60 days after the end of treatment. The radiographs were scored evaluated by two examiners to classify periapical repair: total repair, partial repair, doubtful repair, or no repair. Enterococcus faecalis was found more frequently in G1 than G2. Actinomyces israelii was found equally in G1 and G2. Evaluation of the two bacteria between collections 1, 2 and 3, showed that there was no difference, both in G1 and in G2. There was association between the variables group and repair classification in radiographs evaluation. APDT did not promote better results in endodontic treatment, being similar to conventional treatment. However, this study pointed out that molecular methods may not be efficient in detecting bacteria after treatment, and colony-forming units may complement, being an effective quantifying method. Therefore, new studies must be carried out to show the possible effectiveness of aPDT.

Qualitative and quantitative molecular analysis of bacteria in root canals of primary teeth with pulp necrosis

Information about bacterial diversity, such as the number of each species in the root canals of primary teeth, contributes to improving our effective management of infections of endodontic origin in primary teeth. This study made a qualitative and quantitative assessment of the bacteria in the root canals of primary teeth with necrotic pulp, using the fluorescence in situ hybridization (FISH) technique. Thirty-one primary teeth with pulp necrosis from 31 children were evaluated using the FISH technique, to detect the presence and density of Aggregatibacter actinomycetemcomitans, Campylobacter rectus, Enterococcus faecalis, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Streptococcus, Streptococcus mutans, Streptococcus sobrinus, Tannerella forsythia and Treponema denticola. Descriptive measures explained the data related to density, and Student's t-test assessed the differences among the densities of each bacterium, according to signs and symptoms. The bacterial density was paired and correlated. All bacteria tested were detected and identified in all the samples. The average number of bacterial individuals from each species ranged from 1.9 x 108 cells/mL (S. mutans) to 3.1 x 108 cells/mL (F. nucleatum) (p > 0.05). The sum of the mean counts of each bacterium represented almost 80% of the entire microbial community. Patients with pain had significantly more T. denticola, and those with edema showed a greater density of Streptococcus and P. nigrescens (p < 0.05). This study revealed that all 12 bacteria evaluated were found in all primary teeth with pulp necrosis. There was no predominance among the species studied; all species had a similar number of individuals.

Analysis of survival and factors associated with failure of primary tooth pulpectomies performed under general anaesthesia in children from South China

BACKGROUND

Pulpectomy is a technique recommended for treatment of irreversible pulp inflammation or necrosis. Treatment-related variables and patient factors may affect the prognosis of pulpectomy.

AIM

To investigate the survival and related predictors associated with failure of pulpectomies performed under general anaesthesia for early childhood caries.

DESIGN

Dental records of 124 patients, who underwent pulpectomy as part of comprehensive dental treatment under general anaesthesia, were reviewed and assessed. Relapse of pulpitis and periodontal periodontitis were evaluated by clinical examination and periapical film assessment at each follow-up appointment after original treatment.

RESULTS

A total of 389 teeth of 124 children were evaluated. By the end of the fourth year, 45% of teeth with pulpitis and 46% of teeth with periapical periodontitis were estimated to relapse; the median (interquartile range) number of years to relapse was 3.5 (3.4-3.8) and 3.0 (1.8-3.0) years, respectively. The follow-up frequency, number of teeth extracted, plaque index, tooth position, type of restoration, pulp status, and quality of root canal filling were observed to have independent effects on relapse.

CONCLUSION

Recurrence came earlier in teeth diagnosed with periapical periodontitis than those with pulpitis. Both treatment-related variables and patient factors could affect the prognosis of pulpectomy.

Antibiofilm activity of natural zeolite supported NanoZnO: inhibition of Esp gene expression of Enterococcus faecalis

AIM

To evaluate the antibiofilm effect and esp gene downregulation of Enterococcus faecalis through nanozinc oxide fabricated on natural zeolite (NanoZnO/Ze). Materials & methods:Zeolite and NanoZnO/Ze materials were characterized by x-ray diffraction, x-ray fluorescence and field emission scanning electron microscopy coupled with energy dispersive x-ray. Atomic absorption spectroscopy was used to evaluate zinc release. E. faecalis biofilm formation and its esp gene expression were assessed under nanocomposite treatment.

RESULTS

Spherical-shaped ZnO nanoparticles with an average size of 30 nm were dispersed on the zeolites surface. The leakage of cationic zinc from NanoZnO/Ze displayed a long lasting and considerable release content (p < 0.0001) compared with ZnO/Ze. NanoZnO/Ze effectively inhibited (p < 0.0001) biofilm formation and affected esp gene downregulation of E. faecalis.

CONCLUSION

Our results show that NanoZnO/Zeolite can potentiate against biofilm infections due to E. faecalis and possibly other pathogens.