Luciana Moura Sassone

A Microbiological Profile of Symptomatic Teeth with Primary Endodontic Infections

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 = 30) or asymptomatic (n = 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 (x10(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 < 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.

Antimicrobial activity of sodium hypochlorite and chlorhexidine by two different tests

The aim of this study was to evaluate the antimicrobial capacity of sodium hypochlorite (1% and 5%) and chlorhexidine (0.12%, 0.5% and 1%) with or without the addition of organic material (bovine serum albumin, BSA) against some bacterial samples (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Porphyromonas gingivalis and Fusobacterium nucleatum) using two activity tests (contact and diffusion agar tests). In the contact test (first model), bacterial samples were kept in contact with each irrigating solution for different time intervals: immediately (t(0)), 5 min (t(5)), 15 min (t(15)) and 30 min (t(30)). The agar diffusion test was the second model used. In half the specimens, 0.5% BSA was added to simulate organic tissue present in the root canal. Bacterial growth was evaluated for each microorganism and activity test. Each test was repeated 10 times. In the contact test, 0.12% chlorhexidine solution (CHX) did not eliminate E. faecalis at any tested time. CHX at 0.5% eliminated all strains except E. faecalis after immediate contact. All strains were eliminated by 1% CHX, 1% NaOCl and 5% NaOCl. BSA did not interfere with the antimicrobial activity of the irrigating solutions. In the agar diffusion test, all solutions exhibited zones of antimicrobial activity; however, BSA interfered with the antimicrobial activity of NaOCl and CHX. Under the condition of the contact test, the 0.12% CHX was ineffective in eliminating E. faecalis, while 0.5% CHX, 1% CHX, 1% NaOCl and 5% NaOCl showed antibacterial effectiveness against all the tested bacterial strains. The addition of an organic load interfered with the accuracy of the agar diffusion test.

Microbial Diversity in Persistent Root Canal Infections Investigated by Checkerboard DNA-DNA Hybridization

INTRODUCTION The aim of the present study was to investigate the composition of the root canal microbiota in endodontic failures in order to identify and quantify these microorganisms. METHODS Microbiological samples were taken from 36 root canals with persistent endodontic infection. The presence, levels, and proportions of 79 bacterial species were determined by checkerboard DNA-DNA hybridization. The Pearson correlation coefficient was used to investigate the relations between bacterial counts and clinical conditions (P ≤ .05). RESULTS Enterococcus faecium (36%), Streptococcus epidermidis (36%), Eubacterium saburreum (28%), Parvimonas micra (28%), Streptococcus sanguis (28%), Capnocytophaga sputigena (28%), Leptotrichia buccalis (28%), Enterococcus faecalis (28%), and Staphylococcus warneri (28%) were the most prevalent species; and there was a low prevalence of Treponema socranskii (3%), Fusobacterium periodonticum (3%), Capnocytophaga gingivalis (3%), and Spiroplasma ixodetis (3%). The highest mean levels were found for the following species: E. faecium, Dialister pneumosintes, Staphylococcus epidermidis and Helicobacter pylori. There was a statistically significant difference between the levels of gram-negative species and gram-positive species (13.5 × 10(5) vs 6.5 × 10(5), respectively). A positive correlation was found between the area of the periapical lesion and the levels of gram-negative and rod species (P < .05). CONCLUSIONS The microbiota from teeth with persistent apical periodontitis presents a mixed and complex profile, hosting E. faecium and S. epidermidis as the most highly prevalent species. No correlation was found between any of the species tested and clinical findings; however, periapical lesions with the largest areas presented higher counts of gram-negative and rod species.

Apical extrusion of bacteria when using reciprocating single-file and rotary multifile instrumentation systems

AIM To evaluate ex vivo, apical bacterial extrusion associated with two reciprocating single-file systems (WaveOne and Reciproc) compared with a conventional multifile rotary system (BioRace). METHODOLOGY Forty-five human single-rooted mandibular incisors were used. Endodontic access cavities were prepared, and root canals were contaminated with an Enterococcus faecalis suspension. Following incubation at 37 °C for thirty days, the contaminated teeth were divided into three groups of 15 specimens each (G1 - Reciproc, G2 - WaveOne and G3 - BioRace). Positive and negative controls consisted of 5 infected teeth and 3 uninfected incisors that were instrumented with one of the tested NiTi systems, respectively. Bacteria extruded from the apical foramen during instrumentation were collected into vials containing 0.9% NaCl. The microbiological samples were taken from the vials and incubated in brain heart agar medium for 24 h. The resulting bacterial titre, in colony-forming units (CFU) per mL, was determined, and these data were analysed by Wilcoxon matched-pairs signed rank test and Kruskal-Wallis H-test. The level of significance was set at α = 0.05. RESULTS No significant difference was found in the number of CFU between the two reciprocating systems (P = 0.41). The conventional multifile rotary system group was associated with significantly higher CFU than both of the two reciprocating groups (P = 0.01). CONCLUSIONS All instrumentation systems extruded bacteria beyond the foramen. However, both reciprocating single-file systems extruded fewer bacteria apically than the conventional multifile rotary system.

Antimicrobial activity of different concentrations of NaOCl and chlorhexidine using a contact test

The purpose of this study was to analyze the in vitro antimicrobial activity of sodium hypochlorite (1% and 5%) and chlorhexidine (0.12%, 0.5% and 1%). Bacterial samples (ATCC) of Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Porphyromonas gingivalis and Fusobacterium nucleatum were submitted to a contact test. Solutions were evaluated at different time intervals: immediately, 5 min, 15 min, and 30 min after contact and repeated 10 times. The results of the contact test showed that 0.12% chlorhexidine did not eliminate E. faecalis at any time interval, while 0.5% and 1% chlorhexidine and 1% and 5% sodium hypochlorite did. These results permit us to conclude that to obtain better antimicrobial activity, chlorhexidine in a concentration greater than 0.12% should be used.

Microbiological evaluation of primary endodontic infections in teeth with and without sinus tract

AIM To examine the microbiological status of primary endodontic infections in teeth with and without a sinus tract. METHODOLOGY Samples were collected by means of a size 15 H-type file and two sterile paper points from 30 cases of primary endodontic infections with (n = 15) or without (n = 15) a sinus tract. The presence of 40 bacterial species was determined by the checkerboard DNA-DNA hybridization method. RESULTS The species found at the highest levels and prevalence were Fusobacterium nucleatum sp. vincentii, Porphyromonas gingivalis, Veillonella parvula, Enterococcus faecalis, Campylobacter gracilis and Neisseria mucosa. Total bacterial counts were similar between teeth with (44 x 10(5)) and without (50 x 10(5)) a sinus tract (t-test: P > 0.05). E. faecalis, Streptococcus anginosus, Capnocytophaga sputigena and Capnocytophaga gingivalis had significantly higher counts in the absence of sinus tract (Mann-Whitney test, P < 0.05). Higher levels of P. gingivalis and Fusobacterium nucleatum sp. nucleatum were observed in cases with a sinus tract. Leptotrichia buccalis (OR = 1.83; CI 95%) and Porphyromonas endodontalis (OR = 2.15; CI 95%) were associated with an increased chance of subjects having a sinus tract. CONCLUSIONS Primary endodontic infections were associated with a large variety of bacterial species. Specific differences between the composition of the microbiota of primary root canal infections were observed in cases with or without a sinus tract.

A Microbiological Profile of Unexposed and Exposed Pulp Space of Primary Endodontic Infections by Checkerboard DNA-DNA Hybridization

INTRODUCTION The aim of this study was to evaluate, by checkerboard DNA-DNA hybridization, the composition of the microbiota of primary endodontic infections in cases associated with exposed (n = 30) and unexposed (n = 30) pulp space. METHODS Samples were collected by means of a #15 H-type file and 2 sterile paper points from 60 single-rooted teeth with necrotic pulp and periapical lesions. The presence, levels, and proportions of 40 bacterial species were determined by checkerboard DNA-DNA hybridization. RESULTS The species found in higher counts (×10(5)) in exposed pulp space cases were Eubacterium saburreum, Fusobacterium nucleatum ssp. vincentii, Tannerella forsythia, Enterococcus faecalis, Neisseria mucosa, Campylobacter gracilis, and Prevotella nigrescens, and in unexposed pulp space cases they were F. nucleatum ssp. vincentii, N. mucosa, E. faecalis, E. saburreum, C. gracilis, and Porphyromonas gingivalis. Counts of F. nucleatum ssp. vincentii, Campylobacter sputigena, Capnocytophaga showae, Treponema socrenskii, Porphyromonas endodontalis, Eikenella corrodens, and Capnocytophaga ochracea were significantly higher in unexposed pulp space cases (P < .05). CONCLUSIONS The data of the present investigation suggested specific differences between the composition of the microbiota in cases with exposed and unexposed pulp space and an association between higher levels of some specific species and unexposed pulp space cases.

Revascularization Technique for the Treatment of External Inflammatory Root Resorption: A Report of 3 Cases

The current external inflammatory root resorption treatment protocol, which uses calcium hydroxide dressing, usually comprises multiple and long-term applications. In addition to the need for multiple appointments for calcium hydroxide replacement, the long-term maintenance of this compound in the root canal weakens dental structures. A modification of this therapy would be advisable. In this clinical investigation, 3 patients with external inflammatory root resorption were submitted to revascularization therapy protocol usually used in teeth with necrotic pulp and open apices. The teeth were treated with revascularization therapy protocol, which consisted of disinfecting the root canal system with triantibiotic paste, filling it with blood clot, and sealing of the root canal with mineral trioxide aggregate and bonded resin restoration. During the follow-up, the pathologic process was arrested with tissue repair in pre-existing radiolucent areas. Reduced mobility was observed in the treated teeth. The 3 cases were followed up for 30, 18, and 15 months, respectively. All teeth remained asymptomatic and retained function and physiological mobility. The therapy used in the revascularization procedure was efficient in the treatment of external inflammatory root resorption, reducing the number of appointments and increasing patient compliance.

In vitro genotoxicity and cytotoxicity in murine fibroblasts exposed to EDTA, NaOCl, MTAD and citric acid

The aim of the present study was to evaluate the capacity of some root canal irrigants to induce genetic damage and/or cellular death in vitro. Murine fibroblast cells were exposed to ethylenediaminetetraacetic acid (EDTA), sodium hypochlorite (NaOCl), MTAD™ and citric acid in increasing concentrations for 3 h at 37ºC. The negative control group was treated with vehicle control (phosphate buffer solution - PBS) for 3 h at 37°C, and the positive control group was treated with methylmetanesulfonate, 1 μM. for 3 h at 37°C. Cytotoxicity was assessed by the trypan blue test and genotoxicity was evaluated by the single cell gel (comet) assay. The results showed that exposure to 2.5% and 5% NaOCl and 8.5% citric acid resulted in a significant cytotoxic effect. NaOCl, EDTA and citric acid did not produce genotoxic effects with respect to the comet assay data for all evaluated concentrations. Although MTAD was not a cytotoxic agent, it showed significant genotoxic effects at all tested concentrations (ANOVA and Tukeys test; p<0.05). NaOCl, EDTA and citric acid were found to be cytotoxic in a dose-dependent manner, but they were not genotoxic. MTAD did not cause cell death, but presented genotoxic effects.

Clinical management of a complicated crown-root fracture: a case report

This report describes the clinical procedures involved in the treatment of a complicated crown-root fracture in the maxillary left central incisor with a wide open apex of a 10-year-old male patient, due to fall from his own height. Post-trauma treatment comprised cervical pulpotomy and adhesive tooth fragment reattachment. After 1 year, clinical and radiograph examinations showed pulp necrosis and an associated periapical lesion. Endodontic therapy with calcium hydroxide-base intracanal dressing, root canal filling and orthodontic extrusion were performed. Extrusion was completed within approximately 16 weeks and the tooth was restored with a post-core system and a prosthetic crown. After a 3 years of follow-up, there was no evidence of apical periodontitis and the tooth was satisfactory both esthetically and functionally.