Abstract Introduction This study evaluated the disinfecting ability of chemomechanical preparation with rotary nickel-titanium instruments, followed by 2 distinct adjunctive procedures in the root ...canals of extracted mandibular molars by means of a correlative analytical approach. Methods Twenty-two extracted mandibular molars were selected and anatomically matched between groups on the basis of micro–computed tomographic analysis. In the first phase of the experiment, root canals were contaminated with Enterococcus faecalis and subjected to chemomechanical preparation with BT RaCe instruments and 2.5% NaOCl irrigation. Then either XP-Endo Finisher instrument or passive ultrasonic irrigation was used to supplement disinfection. Micro–computed tomography was used to show whether the percentage of unprepared areas correlated to bacterial counts. In the second phase, the same teeth were contaminated once again, and the adjunctive procedures were used. Samples from the isthmus area of mesial roots and the apical 5-mm fragment of distal roots were obtained by cryopulverization. Samples taken before and after treatment steps in both phases were evaluated by quantitative polymerase chain reaction and statistically analyzed. Results In phase 1, preparation in both groups resulted in substantial decrease of bacterial counts ( P < .001). The adjunctive approaches led to a further small bacterial reduction, which was significant for XP-Endo Finisher ( P < .05). No significant differences were observed between groups for persisting bacterial counts. Correlative analysis revealed no statistically significant relationship between bacterial reduction and the percentage of unprepared areas ( P > .05). In phase 2, both methods had significant antibacterial effects in the main canal, but none of them could predictably disinfect the isthmus/recess areas. Conclusions Both XP-Endo Finisher and passive ultrasonic irrigation exhibited antibacterial effectiveness, but only the former caused a significant reduction in the bacterial counts after chemomechanical preparation. None of them were effective in predictably disinfecting the isthmus/recess areas.
Abstract Introduction This study compared the efficacy of a reciprocating single-instrument system and a rotary multi-instrument system followed by a supplementary approach with a finishing ...instrument in removing the filling material from curved canals during retreatment. Methods Forty mesial canals from extracted mandibular molars were instrumented and filled. Then, each mesial canal was retreated by using either Reciproc (VDW, Munich, Germany) or Mtwo (VDW) instruments, alternating the technique used per canal from root to root. The working time was recorded, and the percentage of removed filling volume was assessed by means of micro–computed tomography imaging before and after retreatment. Canals still showing filling material remnants were subjected to an adjunctive approach with the XP-Endo Finisher (FKG Dentaire, La Chaux-de-Fonds, Switzerland), and another microCT scan was taken. Data were statistically analyzed with a significance level of 5%. Results The percentage of filling material removed with Mtwo instruments (96%) was significantly higher than Reciproc (89%) ( P < .05), both used up to a final instrument size of 40. Mtwo required less time to remove the filling material than Reciproc ( P < .05). Intragroup analysis in the Reciproc group showed that the R40 instrument removed significantly more filling material than R25 ( P < .05). The supplementary approach with the XP-Endo Finisher was effective in significantly enhancing the removal of filling material ( P < .05). Conclusions The rotary multiple-instrument system was more effective and faster than the reciprocating single-instrument approach in removing previous root canal fillings. As for the Reciproc group, it was observed that the larger instrument promoted significantly better results. The adjunctive finishing instrument XP-Endo Finisher significantly improved filling material removal.
Abstract Introduction This study evaluated the antibiofilm effects of 2 endodontic sealers incorporated with quaternary ammonium polyethylenimine (QPEI) nanoparticles at a 2% concentration (w/w). ...Methods The materials tested were AH Plus and Pulp Canal Sealer EWT (PCS) in the commercial unmodified form or containing 2% QPEI. Antibiofilm assays were conducted by using direct-contact and membrane-restricted tests for evaluation of bacterial viability in biofilms grown onto membranes or paper disks and the crystal violet microtiter-plate assay to evaluate the effects of sealer extracts on the biofilm biomass. Two Enterococcus faecalis strains (ATCC and an endodontic isolate) were used. Results Direct contact and membrane-restricted antibiofilm tests revealed that PCS 2% was the only material to promote total killing of E. faecalis ATCC biofilms. All the materials significantly reduced bacterial counts in E. faecalis ATCC biofilms when compared with the positive control in both tests ( P < .05). In the direct test against E. faecalis RW35, PCS 2% was significantly more effective than the other materials and was the only one that showed significantly lower counts than the positive control ( P < .05). In the crystal violet assay, only AH Plus 2% presented optical density readings significantly lower than the positive control of the ATCC strain ( P < .05). No other significant effects on the biofilm biomass of the 2 E. faecalis strains were observed for any of the sealers tested ( P > .05). Conclusions Addition of QPEI nanoparticles improved the killing ability of PCS against biofilms of both E. faecalis strains and the effects of AH Plus on the biomass of biofilms from the ATCC strain.
Abstract Apical periodontitis is an infectious disease caused by microorganisms colonizing the root canal system. For an optimal outcome of the endodontic treatment to be achieved, bacterial ...populations within the root canal should be ideally eliminated or at least significantly reduced to levels that are compatible with periradicular tissue healing. If bacteria persist after chemomechanical preparation supplemented or not with an intracanal medication, there is an increased risk of adverse outcome of the endodontic treatment. Therefore, bacterial presence in the root canal at the time of filling has been shown to be a risk factor for posttreatment apical periodontitis. About 100 species/phylotypes have already been detected in postinstrumentation and/or postmedication samples, and gram-positive bacteria are the most dominant. However, it remains to be determined by longitudinal studies if any species/phylotypes persisting after treatment procedures can influence outcome. This review article discusses diverse aspects of bacterial persistence after treatment, including the microbiology, bacterial strategies to persist, the requisites for persisting bacteria to affect the outcome, and future directions of research in this field.
Abstract Introduction This clinical study evaluated the influence of the apical preparation size using nickel-titanium rotary instrumentation and the effect of a disinfectant on bacterial reduction ...in root canal–treated teeth with apical periodontitis. Methods Forty-three teeth with posttreatment apical periodontitis were selected for retreatment. Teeth were randomly divided into 2 groups according to the irrigant used (2.5% sodium hypochlorite NaOCl, n = 22; saline, n = 21). Canals were prepared with the Twisted File Adaptive (TFA) system (SybronEndo, Orange, CA). Bacteriological samples were taken before preparation (S1), after using the first instrument (S2), and then after the third instrument of the TFA system (S3). In the saline group, an additional sample was taken after final irrigation with 1% NaOCl (S4). DNA was extracted from the clinical samples and subjected to quantitative real-time polymerase chain reaction to evaluate the levels of total bacteria and streptococci. Results S1 from all teeth were positive for bacteria. Preparation to the first and third instruments from the TFA system showed a highly significant intracanal bacterial reduction regardless of the irrigant ( P < .01). Apical enlargement to the third instrument caused a significantly higher decrease in bacterial counts than the first instrument ( P < .01). Intergroup comparison revealed no significant difference between NaOCl and saline after the first instrument ( P > .05). NaOCl was significantly better than saline after using the largest instrument in the series ( P < .01). Conclusions Irrespective of the type of irrigant, an increase in the apical preparation size significantly enhanced root canal disinfection. The disinfecting benefit of NaOCl over saline was significant at large apical preparation sizes.
Abstract Introduction This ex vivo study evaluated the disinfecting and shaping ability of 3 protocols used in the preparation of mesial root canals of mandibular molars by means of correlative ...bacteriologic and micro–computed tomographic (μμCT) analysis. Methods The mesial canals of extracted mandibular molars were contaminated with Enterococcus faecalis for 30 days and assigned to 3 groups based on their anatomic configuration as determined by μCT analysis according to the preparation technique (Self-Adjusting File ReDent-Nova, Ra’anana, Israel, Reciproc VDW, Munich, Germany, and Twisted File SybronEndo, Orange, CA). In all groups, 2.5% NaOCl was the irrigant. Canal samples were taken before (S1) and after instrumentation (S2), and bacterial quantification was performed using culture. Next, mesial roots were subjected to additional μCT analysis in order to evaluate shaping of the canals. Results All instrumentation protocols promoted a highly significant intracanal bacterial reduction ( P < .001). Intergroup quantitative and qualitative comparisons disclosed no significant differences between groups ( P > .05). As for shaping, no statistical difference was observed between the techniques regarding the mean percentage of volume increase, the surface area increase, the unprepared surface area, and the relative unprepared surface area ( P > .05). Correlative analysis showed no statistically significant relationship between bacterial reduction and the mean percentage increase of the analyzed parameters ( P > .05). Conclusions The 3 instrumentation systems have similar disinfecting and shaping performance in the preparation of mesial canals of mandibular molars.
Abstract Introduction This randomized clinical study compared the antibacterial effects of irrigation with either 2.5% sodium hypochlorite (NaOCl) or 2% chlorhexidine (CHX) during the preparation of ...infected root canals with rotary nickel-titanium instruments. Methods The root canals of 50 single-rooted teeth with apical periodontitis were prepared by using BioRaCe rotary instruments (FKG Dentaire, La Chaux-de-Fonds, Switzerland) and irrigation with either 2.5% NaOCl ( n = 25) or 2% CHX ( n = 25). Samples were taken from the canal at baseline (S1) and after (S2) chemomechanical preparation. DNA was extracted from the clinical samples, and the reduction of the levels of total bacteria and streptococci was evaluated by means of a 16S ribosomal RNA gene-based quantitative polymerase chain reaction assay. Results All S1 samples were positive for the presence of bacteria. After chemomechanical preparation using either 2.5% NaOCl or 2% CHX, 44% and 40% of the root canals still had detectable bacteria, respectively. As for total bacterial counts, a mean number of 3.7 × 105 bacterial cell equivalents was present in S1 samples from the NaOCl group, with a substantial reduction in S2 to a mean of 5.49 × 102 cell equivalents ( P < .001). In the CHX group, a mean bacterial load of 8.77 × 104 cell equivalents occurred in S1, with a significant reduction in S2 to a mean of 2.81 × 103 cells ( P < .001). The differences in both the presence/absence and quantitative data were not statistically significant ( P > .05). Both irrigation protocols were highly effective in reducing the levels of Streptococcus species ( P < .001). Conclusions No significant difference was observed for the clinical antibacterial effectiveness of rotary preparation using either 2.5% NaOCl or 2% CHX as the main irrigant.
Abstract Introduction The purpose of this clinical study was to compare the antimicrobial effects of 2.5% sodium hypochlorite (NaOCl) and 0.12% chlorhexidine digluconate (CHX) when used as irrigants ...during treatment of teeth with apical periodontitis. Methods Forty-seven single-rooted single-canal teeth with necrotic pulps and asymptomatic apical periodontitis were selected for this study according to stringent inclusion/exclusion criteria. Bacterial samples were taken at the baseline (S1) and after (S2) chemomechanical preparation using 2.5% NaOCl ( n = 30) or 0.12% CHX ( n = 17) as the irrigant. Bacterial, archaeal, and fungal presence was evaluated by broad-range polymerase chain reaction (PCR), whereas bacterial identifications were performed by a closed-ended reverse-capture checkerboard approach targeting 28 candidate endodontic pathogens. Results All S1 samples were PCR positive for bacterial presence but negative for both archaea and fungi. Both NaOCl- and CHX-based protocols were significantly effective in reducing the bacterial levels and number of taxa. No significant differences were observed between them in all tested parameters including the incidence of negative PCR results in S2 (40% for NaOCl vs 47% for CHX, p = 0.8), reduction in the number of taxa per canal ( p = 0.3), and reduction in the bacterial levels ( p = 0.07). The most prevalent taxa in S2 samples from the NaOCl group were Propionibacterium acnes , Streptococcus species, Porphyromonas endodontalis , and Selenomonas sputigena . In the CHX group, the most prevalent taxa in S2 were Dialister invisus , Actinomyces israelii , Prevotella baroniae , Propionibacterium acidifaciens , and Streptococcus species. Conclusions Treatment protocols using irrigation with either NaOCl or CHX succeded in significantly reducing the the number of bacterial taxa and their levels in infected root canals, with no significant difference between these substances.
Abstract Introduction This in vivo study compared the antibacterial effectiveness of a reciprocating single-instrument system (Reciproc; VDW, Munich, Germany) and a rotary multi-instrument system ...(BioRaCe; FKG Dentaire, La Chaux-de-Fonds, Switzerland) during the preparation of infected root canals of teeth with primary apical periodontitis. Methods Root canals from single-rooted teeth with necrotic pulps and apical periodontitis were instrumented using either Reciproc ( n = 29) or BioRaCe ( n = 30) instruments under irrigation with 2.5% sodium hypochlorite. DNA was extracted from samples taken before and after preparation and subjected to quantitative analysis of total bacteria and streptococci by using the quantitative real-time polymerase chain reaction. Results All initial samples were positive for the presence of bacteria, with median numbers of 7.1 × 105 and 1.31 × 105 bacterial cells for the Reciproc and BioRaCe groups, respectively. After preparation with Reciproc and BioRaCe, 16 (55%) and 15 (50%) root canals still had detectable bacteria with median counts of 7.05 × 102 and 6.03 × 101 , respectively. Both systems were highly effective in reducing the total bacterial counts ( P < .001), and there were no significant differences between them ( P > .05). Streptococci were highly frequent, and both systems succeeded in significantly reducing their levels ( P < .001). Conclusions Both reciprocating single-instrument and rotary multi-instrument systems were highly effective in reducing the counts of total bacteria and streptococci in root canals of teeth with apical periodontitis. Regardless of the system used, approximately one half of the teeth still had detectable bacteria.
Abstract Introduction Clinicians routinely face conditions in which they have to decide whether the dental pulp can be saved or not. This study evaluated how reliable the clinical diagnosis of normal ...pulp/reversible pulpitis (savable pulp) or irreversible pulpitis (nonsavable pulp) is when compared with the histologic diagnosis. Methods The study material consisted of 95 teeth collected consecutively in a general practice over a 5-year period and extracted for reasons not related to this study. Based on clinical criteria, teeth were categorized as having normal pulps, reversible pulpitis, or irreversible pulpitis. The former 2 were grouped together because they represent similar conditions in terms of prognosis. Teeth were processed for histologic and histobacteriologic analyses, and pulps were categorized as healthy, reversibly inflamed, or irreversibly inflamed according to defined criteria. The number of matching clinical/histologic diagnosis was recorded. Results The clinical diagnosis of normal pulp/reversible pulpitis matched the histologic diagnosis in 57 of 59 (96.6%) teeth. Correspondence of the clinical and histologic diagnosis of irreversible pulpitis occurred in 27 of 32 (84.4%) cases. Infection advancing to the pulp tissue was a common finding in teeth with irreversible pulpitis but was never observed in normal/reversibly inflamed pulps. Conclusions Findings using defined criteria for clinical and histologic classification of pulp conditions revealed a good agreement, especially for cases with no disease or reversible disease. This means that the classification of pulp conditions as normal pulps, reversible pulpitis, and irreversible pulpitis has high chances of guiding the correct therapy in the large majority of cases. However, there is still a need for refined and improved means for reliable pulp diagnosis.