Endodontic cellulitis 'flare-up'. Case report

In Vitro Comparison of Apically Extruded Debris during Root Canal Preparation of Mandibular Premolars with Manual and Rotary Instruments

Background and aims. During root canal preparation, debris extruded beyond the apical foramen may result in periapical inflammation and postoperative pain. To date no root canal preparation method has been developed that extrudes no periapical debris. The purpose of this study was to identify a system leading to minimal extrusion of debris from the apical foramen. The study was conducted to comparatively evaluate the amount of apical extrusion of debris during root canal preparation using hand ProTaper and GT rotary and RaCe rotary instruments using crown-down technique.

Materials and methods. Ninety freshly extracted human single-rooted mandibular premolars were equally assigned to three groups (n=30). The root canals were instrumented using hand ProTaper, GT rotary and RaCe rotary systems. Debris and irrigant extruded from the apical foramen were collected into vials. The mean weight of the remaining debris was calculated for each group and subjected to statistical analysis.

Results. ANOVA was used to compare the mean dry weights of the debris extruded in the three groups, followedby post hoc Tukey tests for multiple comparisons the between groups. Highly significant differences were found in the amount of debris extruded among all the groups (P<0.001). The ProTaper group exhibited the highest mean debris weight (0.8293±0.05433 mg) and the RaCe system exhibited the lowest mean debris weight (0.1280±0.01606 mg).

Conclusion. All the systems tested resulted in apical extrusion of debris. However, the hand ProTaper files extruded a significantly higher amount of debris than GT and RaCe systems.

Clinical and pharmacological management of endodontic flare-up

Knowledge of the causes of and mechanisms behind interappointment pain in endodontics is of utmost importance for the clinician to properly prevent or manage this undesirable condition. The causative factors of interappointment pain encompass mechanical, chemical, and microbial injuries to the pulp or periradicular tissues, which are induced or exacerbated during root canal treatment. This review article underlines the various treatment modalities for relief of pain and swelling in such situations, including premedication, drainage establishment, relief of occlusion, and intracanal and systemic medication.

Antibacterial Effect of Selected Root-End Filling Materials

The purpose of this study was to evaluate the antibacterial activity of leachable components of selected root-end filling materials: amalgam, ProRoot MTA (mineral trioxide aggregate), Intermediate Restorative Material (IRM), Super Bond C&B, Geristore, Dyract, Clearfil APX composite with SE Bond, or Protect Bond. The direct contact test (DCT) with Staphylococcus aureus, Enterococcus faecalis, and Pseudomonas aeruginosa, was used. The materials were tested immediately after application to the microtiter wells (fresh samples) and after setting for 3 days (set samples). Ten microliters of bacterial suspension was added to each well for direct contact with each material for 1 h at 37 degrees C. Growth of surviving bacteria was then measured in a microplate spectrophotometer hourly at 620 nm for 15 h. Twelve uncoated wells using identical inoculum size served as positive controls. The data obtained at the end of 15 h was subjected to one-way ANOVA and post hoc comparisons were done using Tamhane's T2 test. Fresh samples of all materials showed a 3-h delay in exponential growth of both E. faecalis and S. aureus, and a 5-h delay in growth of P. aeruginosa. Set samples of IRM and ProRoot MTA cements showed generally greater antibacterial activity than the other materials: both completely inhibited P. aeruginosa, and both delayed or limited growth of E. faecalis. The DCT, by being quantitative and virtually independent of solubility and diffusion, was found suitable to assay solid root-end filling materials. IRM and ProRoot MTA were generally more potent inhibitors of bacterial-growth than the other tested materials.

Microbial causes of endodontic flare-ups

LITERATURE REVIEW

Inter-appointment flare-up is characterized by the development of pain, swelling or both, following endodontic intervention. The causative factors of flare-ups encompass mechanical, chemical and/or microbial injury to the pulp or periradicular tissues. Of these factors, microorganisms are arguably the major causative agents of flare-ups. Even though the host is usually unable to eliminate the root canal infection, mobilization and further concentration of defence components at the periradicular tissues impede spreading of infection, and a balance between microbial aggression and host defences is commonly achieved. There are some situations during endodontic therapy in which such a balance may be disrupted in favour of microbial aggression, and an acute periradicular inflammation can ensue. Situations include apical extrusion of infected debris, changes in the root canal microbiota and/or in environmental conditions caused by incomplete chemo-mechanical preparation, secondary intraradicular infections and perhaps the increase in the oxidation-reduction potential within the root canal favouring the overgrowth of the facultative bacteria. Based on these situations, preventive measures against infective flare-ups are proposed, including selection of instrumentation techniques that extrude lesser amounts of debris apically; completion of the chemo-mechanical procedures in a single visit; use of an antimicrobial intracanal medicament between appointments in the treatment of infected cases; not leaving teeth open for drainage and maintenance of the aseptic chain throughout endodontic treatment. Knowledge about the microbial causes of flare-ups and adoption of appropriate preventive measures can significantly reduce the incidence of this highly distressing and undesirable clinical phenomenon.

Antimicrobial activity and flow rate of newer and established root canal sealers

Endodontic sealers that possess both optimum flow ability and antimicrobial properties may theoretically assist in the elimination of microorganisms located in confined areas of the root canal system. The antimicrobial effects and the flow rate of the following sealers were investigated and compared: Kerr Pulp Canal Sealer EWT, Grossman's Sealer, ThermaSeal, Sealer 26, AH Plus, and Sealer Plus. The agar diffusion test was used to assess the antimicrobial activity of the sealers. In the flow assay, the sealers were placed between two glass slabs and a weight of 500 g was placed on the top of the glass. The diameters of the formed discs were recorded. All root canal sealers tested showed some antimicrobial activity against most of the microorganisms. There were no significant differences between the materials tested (p > 0.05). All root canal sealers also flowed under the conditions of this study. Statistical analysis of the results revealed that AH Plus and Kerr Pulp Canal Sealer EWT had flow values significantly superior to the other sealers tested (p > 0.05). Taken together, these findings suggest that these sealers have the potential to help in the microbial control in the root canal system.

Pathogenicity of facultative and obligate anaerobic bacteria in monoculture and combined with either Prevotella intermedia or Prevotella nigrescens

The pathogenicity of obligate and facultative anaerobic bacteria commonly found in endodontic infections was tested using a mouse model. The capacity of inducing abscesses was evaluated seven days after subcutaneous injection of the bacteria in pure culture and in combinations with either Prevotella intermedia or Prevotella nigrescens. Nine of the fifteen bacterial strains tested were pathogenic in pure culture. No statistically significant differences were detected between these strains in pure culture and in mixtures with either P. intermedia or P. nigrescens. Synergism between the bacterial strains was only apparent when associating Porphyromonas endodontalis with P. intermedia or P. nigrescens. Histopathological examination of tissue sections from induced abscesses revealed an acute inflammatory reaction, dominated by polymorphonuclear leukocytes. Sections from the control group using sterile medium showed no evidence of inflammatory reaction.

Antibacterial effects of endodontic irrigants on black-pigmented gram-negative anaerobes and facultative bacteria

The antibacterial effect of endodontic irrigants was evaluated against four black-pigmented Gram-negative anaerobes and four facultative anaerobic bacteria by means of the agar diffusion test. All solutions used were inhibitory against all bacterial strains tested. A 4% NaOCl solution provided the largest average zone of bacterial inhibition of this study that was significantly superior when compared with the other solutions, except 2.5% NaOCl (p < 0.05). Based on the averages of the diameters of the zones of bacterial growth inhibition, the antibacterial effects of the solutions could be ranked from strongest to weakest as follows: 4% NaOCl; 2.5% NaOCl; 2% chlorhexidine; 0.2% chlorhexidine, EDTA, and citric acid; and 0.5% NaOCl.