Prevalence of Treponemaspp. in endodontic retreatment-resistant periapical lesions

[Acute apical abscess and associated factors in patients during the covid-19 pandemic in a health center in Acapulco, Mexico.]

Objective

To estimate the prevalence of acute apical abscess and identify associated factors in patients of a health center from Acapulco, Mexico.

Material and methods

Epidemiological study that collected clinical records of patients during the period of october 2021. Sociodemographic and housing information was collected, as well as personal pathological and non-pathological history and a record of the diagnosis of the periapical lesion based on its clinical characteristics issued by the operator on duty. Through multivariate analysis, a factor associated with acute apical abscess was identified with the odds ratio and its 95% confidence interval as estimators of the strength of association with CIETmap statistical software.

Results

The 37% (32/87) of patients were diagnosed with the infection. In terms of gender, females were the most affected with a proportion of 56% (18/32). The most common cause was caries with 72% (23/32). The right upper second premolar was the most affected tooth with 25% (8/32). One associated factor was identified, age 36 to 62 years (ORa=3.54; CI95%a=1.27 -16.62).

Conclusion

The morbidity rate of the infection was moderate, and it is a common pathology in stomatological emergency consultations, so it is important for the professional in charge of the area to manage it clinically. It will be important to implement oral health education strategies aimed at different age groups to raise awareness of the cariogenic process and its consequences.

Confocal laser scanning microscopy evaluation of roots subjected to activation protocol in endodontic microsurgery

This study evaluated the penetration of the irrigant subject to activation after performing retro-preparation in endodontic microsurgery. Forty mandibular premolars were prepared and filled. Subsequently, 1 mm from the root apex was cut using a multi-blade bur and the retro-preparation was performed. In group 1, the retro-cavity was cleaned with 2 mL of saline and then with 2 mL of 5.25% NaOCl gel mixed with 0.1% Rhodamine B. In group 2, the retro-cavity was cleaned with 2 mL of saline, 17% EDTA gel was activated ultrasonically for 30 s and 5.25% NaOCl gel was mixed with 0.1% Rhodamine B and activated for 30 s. After 7 days, the roots were cut at 1mm from the apex and the slices were evaluated with confocal laser scanning microscopy. The samples of group 2 showed statistically better results. The activation protocol proposed resulted in enhanced irrigant penetration when compared to the traditional.

Putative periodontal pathogens in persisting periodontal pockets of endodontic origin

Background:

The microbial profile of endodontically treated teeth, presenting with a persisting deep periodontal pocket, secondary to a primary endodontic lesion, draining through the gingival crevice, has received very less attention. This observational study was done to evaluate if these sites with persisting pockets of endodontic origin persist because they have acquired bacteria which are considered as putative periodontal pathogens.

Materials and Methods:

Subgingival plaque samples were collected from fifty patients diagnosed with a primary endodontic and a secondary periodontal lesion that persisted even after completion of the root canal treatment. Clinical parameters such as probing pocket depth, clinical attachment level, plaque index, furcation, and tooth mobility were recorded. Real-time polymerase chain reaction was used to determine the possible association between six bacteria, which are frequently associated with periodontal and endodontic lesions.

Results:

The mean cycle threshold value for Treponema denticola (Td) was found to be 33.74, and for Enterococcus faecalis (Ef), it was 34.39. With regard to clinical attachment loss, Td (P < 0.04) and Parvimonas micra (P < 0.05) had a significant correlation.

Conclusion:

Ef (92%) and Td (86%) were found to be most prevalent. Porphyromonas gingivalis and Tannerella forsythia were in minimal to nonexistent levels.

Analysis of microorganisms in periapical lesions: A systematic review and meta-analysis

AIMS

The aim of this study was to systematically review the literature on prevalence of microorganisms and their viability/activity in endodontic periapical lesions.

DESIGN

Literature research was performed on five electronic biomedical databases from their start dates to June 2020. Only studies evaluating the presence of microorganisms in periapical lesions in human permanent teeth with secondary/persistent infection were included. Two reviewers independently assessed the eligibility for inclusion, extracted data and evaluated the risk of bias. Meta-analysis and binominal tests were used to analyse the resulting data.

RESULTS

From the 1,313 records found, 23 full-texts were included for qualitative and quantitative analysis. The prevalence of microorganisms in endodontic periapical lesions was 87 % (95 % CI, 75-94) and the prevalence of viable/active microorganisms was 82 % (95 % CI, 66-91). There were statistical differences in the geographic area subgroup and between viable bacteria and active viruses. The most common detection method of microorganisms was the molecular one (69 %), and the most prevalent bacteria were the species Actinomyces, Fusobacterium and Prevotella (40 %). Most of the included studies had moderate risk of bias.

CONCLUSIONS

The prevalence of microorganisms in endodontic periapical lesions was 87 % and the prevalence of viable/active microorganisms was 82 %.

Passive Filtration, Rapid Scanning Electron Microscopy, and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Treponema Culture and Identification from the Oral Cavity

We present here a new passive-filtration-based culture device combined with rapid identification with a new electron microscope (Hitachi TM4000) for the detection and culture of Treponema species from the human oral cavity. Of the 44 oral samples cultivated, 15 (34%) were found to be positive for Treponema using electron microscopy and were also culture positive. All were subcultured on agar plates; based on genome sequencing and analyses, 10 were strains of Treponema pectinovorum and 5 were strains of Treponema denticola The 29 samples that were negative for Treponema remained culture negative. In addition, 14 Treponema species ordered from the DSMZ collection were cultured in the T-Raoult culture medium optimized here. Finally, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was used and 30 novel spectra were added to the MALDI-TOF MS database. We have successfully developed a new and effective method for treponemal detection, culture, and identification.

Methylene Blue and Hydrogen Peroxide for Photodynamic Inactivation in Root Canal - A New Protocol for Use in Endodontics

Objective

Antimicrobial photodynamic therapy (aPDT) is a controversial approach for endodontic disinfection. The objective of this study was to test the photosensitiser (PS) concentration and assess the optical shielding phenomenon, the use of hydrogen peroxide (H₂O₂) and minimal energy irradiation to optimise endodontic aPDT for suggesting a protocol for clinical use.

Methods

Different parameters for aPDT were tested. Aqueous solutions of methylene blue (MB) at 50, 100, 150 and 300 μM were tested in vitro for optical shield and reactive oxygen species (ROS) production by the reduction of N,N-dimethyl-4-notrosoaniline (RNO) at 440 nm absorbance when irradiated using a diode laser (660 nm). Ten single-rooted teeth were inoculated with bioluminescent bacteria Pseudomonas aeruginosa for 72 hours to form biofilms. Bioluminescence imaging was used to serially evaluate the minimum energy necessary during endodontic aPDT using MB and a diode laser coupled to an optical fibre for intracanal microbial reduction. In addition, teeth (n=21) infected with Enterococcus faecalis were treated with sequential combinations of endodontic aPDT and H₂O₂ and the colony-forming unit (CFU) was determined.

Results

ROS production was inversely proportional to the MB concentration in the solution due to quenching of MB. Optical shielding limited light penetration at high MB concentrations. The use of H₂O₂ before aPDT achieved higher disinfection compared to conventional aPDT or when MB was irradiated in an H₂O₂ solution. Energy irradiation of 9.6 J achieved a significant reduction and further light delivery did not produce further reduction.

Conclusion

PS concentration of about 50 μM, biofilm pre-treatment with H₂O₂ for 1 min and energy irradiation around 10 J appear to be an effective protocol for endodontic aPDT.

Microbial signatures of oral dysbiosis, periodontitis and edentulism revealed by Gene Meter methodology

Conceptual models suggest that certain microorganisms (e.g., the "red" complex) are indicative of a specific disease state (e.g., periodontitis); however, recent studies have questioned the validity of these models. Here, the abundances of 500+ microbial species were determined in 16 patients with clinical signs of one of the following oral conditions: periodontitis, established caries, edentulism, and oral health. Our goal was to determine if the abundances of certain microorganisms reflect dysbiosis or a specific clinical condition that could be used as a 'signature' for dental research. Microbial abundances were determined by the analysis of 138,718 calibrated probes using Gene Meter methodology. Each 16S rRNA gene was targeted by an average of 194 unique probes (n=25nt). The calibration involved diluting pooled gene target samples, hybridizing each dilution to a DNA microarray, and fitting the probe intensities to adsorption models. The fit of the model to the experimental data was used to assess individual and aggregate probe behavior; good fits (R²>0.90) were retained for back-calculating microbial abundances from patient samples. The abundance of a gene was determined from the median of all calibrated individual probes or from the calibrated abundance of all aggregated probes. With the exception of genes with low abundances (<2 arbitrary units), the abundances determined by the different calibrations were highly correlated (r~1.0). Seventeen genera were classified as 'signatures of dysbiosis' because they had significantly higher abundances in patients with periodontitis and edentulism when contrasted with health. Similarly, 13 genera were classified as 'signatures of periodontitis', and 14 genera were classified as 'signatures of edentulism'. The signatures could be used, individually or in combination, to assess the clinical status of a patient (e.g., evaluating treatments such as antibiotic therapies). Comparisons of the same patient samples revealed high false negatives (45%) for next-generation-sequencing results and low false positives (7%) for Gene Meter results.