Comparison of OneShape, 2Shape and One Curve endodontic instruments for debris and irrigant extrusion.

BACKGROUND: Better understanding is needed about the debris-and-irrigant-extrusion potential of the instruments used for root canal preparation procedures, manufactured of different heat-treated alloys. OBJECTIVES: The aim of the study was to evaluate the single-file nickel-titanium (NiTi) rotary system OneShape® and compare it with 2 different heat-treated instrumentation systems produced by the same manufacturer - a single-file C-wire system (One Curve®) and a multi-file T-wire system (2Shape®) - in terms of debris and irrigant extrusion. MATERIAL AND METHODS: The mesiobuccal root canals of 51 extracted mandibular molar teeth were selected for the study. The roots were applied to the test apparatus prepared with the Myers and Montgomery method. The roots were divided into 3 groups according to the instrumentation system: OneShape; One Curve; and 2Shape. The root canals were prepared according to the manufacturer's instructions. The analysis of variance (ANOVA) and the post hoc Tukey tests were used to evaluate the significance of the amount of the extruded debris and irrigant (p < 0.05). RESULTS: The One Curve group produced less debris extrusion than the 2Shape group (p < 0.05). There were no significant differences between the 2Shape and OneShape (p = 0.136), or the One Curve and OneShape groups (p = 0.159). The weight of the extruded irrigant was significantly lower for the One Curve group as compared to other systems (p < 0.05). The mean weight of the extruded irrigant did not differ significantly for the 2Shape and OneShape groups (p = 0.976). CONCLUSIONS: The C-wire One Curve system was associated with less apical irrigant extrusion in comparison with the OneShape and 2Shape systems. The amount of debris extrusion produced by the One Curve system was similar to that produced by the OneShape system and lower than in the case of the 2Shape system.

Mechanical Allodynia in Healthy Teeth Adjacent and Contralateral to Endodontically Diseased Teeth: A Clinical Study.

INTRODUCTION: The aims of this study were to examine whether teeth adjacent and contralateral to endodontically diseased teeth showed co-occurring mechanical allodynia and to determine whether demographic and clinical variables were involved in such associations. METHODS: Patients with irreversibly inflamed or necrotic permanent first molars or second premolars were examined. From the 348 eligible patients (160 men and 188 women; mean age ± standard deviation = 30.4 ± 10.0 years), data on age, sex, health status, current presence of pain, tooth type, dental arc, and pulpal diagnosis were collected. Percussion testing was applied to all posterior teeth, and the degrees of pain were recorded using a 4-point verbal scale as follows: none to slight (coded as 0) and moderate to severe (coded as 1). Following association rule mining (with minimum support and confidence levels of 0.1), univariate and multiple logistic regression analyses were performed at various stringency levels (α = 0.05). RESULTS: The number of painful associations was greater ipsilaterally than contralaterally and distally than mesially and increased with the severity of percussion pain in the diseased tooth. Successful regression models were established for the ipsilateral (between the diseased tooth and adjacent teeth; current pain: odds ratio = 3.37; 95% confidence interval, 1.94-5.83) and contralateral (between the diseased tooth and the tooth distal to the contralateral symmetrical tooth; dental arc: odds ratio = 2.40; 95% confidence interval, 1.21-4.76) sides (P < .05). CONCLUSIONS: Healthy teeth adjacent and contralateral to symptomatic diseased teeth exhibited percussion sensitivity. Patients' current pain and dental arc, respectively, were involved in such painful associations.

Volumetric Evaluation of Void/Gap Formation and Microleakage Cementing Fiber Posts on Extracted Teeth with Three Different Cements.

PURPOSE: To evaluate microleakage in roots restored with fiber posts cemented using three different luting cements, to measure the volume of voids/gaps within the obturated/postcemented root canals, and to examine whether microleakage and the volume of voids/gaps were correlated. MATERIALS AND METHODS: Thirty-six extracted human mandibular incisors were decoronated, and the root canals were obturated using gutta-percha and sealer in the experimental groups (n = 30). Six roots were used as controls. A standard post space was prepared, and an identically sized fiber post was cemented in each experimental specimen using one of three luting cements (Panavia F2.0, Bifix SE, GC FujiCEM; n = 10 each). The specimens were scanned using micro-computed tomography, and the volume of voids/gaps was determined. The specimens were then subjected to a fluid filtration assay to evaluate microleakage. RESULTS: The volume of voids/gaps was significantly lower in the GC FujiCEM group, and significantly less microleakage occurred in the Bifix SE group compared with other groups (both p < 0.001). A significant correlation between the volume of voids/gaps and leakage was found only in the Panavia F2.0 group (p = 0.003; r = 0.830). No such correlation was found in the analysis of all groups combined. CONCLUSIONS: The group with the greatest volume of voids/gaps (Bifix SE) showed the least microleakage, and the group with the smallest volume of voids/gaps (GC FujiCEM) showed the most microleakage. Panavia F2.0 ranked between and exhibited significant correlation.

Predicting intraoperative pain in emergency endodontic patients: clinical study.

This prospective observational study sought to investigate the incidence of intraoperative pain (IOP) among emergency endodontic patients and to construct an IOP prediction model that includes preoperative pain level (PPL). All patients who underwent emergency endodontic treatment at Gazi University, Ankara, Turkey, during the spring term of 2016 were considered for inclusion in the study. Demographic and clinical variables and PPL were recorded. Local anesthesia was provided to all patients before beginning routine endodontic treatment. IOP was defined as the condition of requiring supplementary anesthesia before the working length was established and exhibiting persistent moderate or severe pain despite supplementary anesthesia. Data from 85% and 15% of 435 patients (178 men, 257 women; mean age: 35 years) were used to develop predictive models by multiple logistic regression analysis and to test external validity of the models, respectively. Two multiple logistic regression models achieved good model fits. Model 1 included age, pulpal diagnosis, and arc (p < 0.05). In addition to these variables, Model 2 included periapical diagnosis and PPL (p < 0.15). Models 1 and 2 showed accuracies of 0.76 and 0.75, sensitivities of 0.74 and 0.77, and specificities of 0.76 and 0.74, respectively for the modeling data (internal validity), and accuracies of 0.82 and 0.80, sensitivities of 0.83 and 0.67, and specificities of 0.81 and 0.81, respectively for the control data (external validity). The IOP incidence was 10.3%. IOP in patients undergoing emergency endodontic treatment can be successfully predicted by using models that account for demographic and clinical variables, including PPL.

Predicting intraoperative pain in emergency endodontic patients: clinical study

Abstract This prospective observational study sought to investigate the incidence of intraoperative pain (IOP) among emergency endodontic patients and to construct an IOP prediction model that includes preoperative pain level (PPL). All patients who underwent emergency endodontic treatment at Gazi University, Ankara, Turkey, during the spring term of 2016 were considered for inclusion in the study. Demographic and clinical variables and PPL were recorded. Local anesthesia was provided to all patients before beginning routine endodontic treatment. IOP was defined as the condition of requiring supplementary anesthesia before the working length was established and exhibiting persistent moderate or severe pain despite supplementary anesthesia. Data from 85% and 15% of 435 patients (178 men, 257 women; mean age: 35 years) were used to develop predictive models by multiple logistic regression analysis and to test external validity of the models, respectively. Two multiple logistic regression models achieved good model fits. Model 1 included age, pulpal diagnosis, and arc (p < 0.05). In addition to these variables, Model 2 included periapical diagnosis and PPL (p < 0.15). Models 1 and 2 showed accuracies of 0.76 and 0.75, sensitivities of 0.74 and 0.77, and specificities of 0.76 and 0.74, respectively for the modeling data (internal validity), and accuracies of 0.82 and 0.80, sensitivities of 0.83 and 0.67, and specificities of 0.81 and 0.81, respectively for the control data (external validity). The IOP incidence was 10.3%. IOP in patients undergoing emergency endodontic treatment can be successfully predicted by using models that account for demographic and clinical variables, including PPL.

Predictive Model of Intraoperative Pain during Endodontic Treatment: Prospective Observational Clinical Study.

INTRODUCTION: This observational study sought to assess the incidence of intraoperative pain (IOP) among patients receiving endodontic treatment and to construct a model for predicting the probability of IOP. METHODS: All patients attending the endodontic training clinic at Gazi University, Ankara, Turkey, during the spring term of 2014 were examined (N = 2785 patients; observation completed in 1435 patients; male: 628, female: 807; mean age: 39 years; 1655 teeth total). Demographic and clinical variables were recorded for patients requiring primary endodontic treatment. Local anesthesia was administered and routine endodontic treatment commenced. After the working length was established, each patient was asked to report any pain according to a visual analog scale. Supplementary local infiltration anesthesia was administered if necessary. If pain continued despite supplementary anesthesia, then the pain score was immediately assessed. A visual analog scale score corresponding to more than mild pain indicated IOP. A predictive model was constructed with multiple logistic regression analysis from the data of 85% of cases, with the remaining 15% of cases being used to test the external validity of the model. RESULTS: The incidence of IOP was 6.1% (101/1655 cases). One tooth from each patient was randomly selected, with 1435 teeth being retained for further analysis. A multiple logistic regression model was constructed with the variables age, tooth type, arc, pulpal diagnosis, pain present within the previous 24 hours, and anesthetic solution (P < .05). Good fits were obtained for the final model and external control, with a correct classification rate (efficiency) of 0.78, sensitivity (true positive rate) of 0.63, and specificity (true negative rate) of 0.79 for the external control. CONCLUSIONS: A successful predictive model of IOP was constructed with demographic and clinical variables.

Root and canal symmetry in the mandibular anterior teeth of patients attending a dental clinic: CBCT study.

The aims of this study were to evaluate the number of roots/root canals in the mandibular anterior teeth of a Turkish population, to assess the relationship between gender or age and the frequency of two canals in a single root, and to determine the symmetry in root/root canal numbers between contralateral sides among patients. Cone-beam computed tomography images (n = 1128; 6253 teeth) taken at the Department of Dentomaxillofacial Radiology of the Faculty of Dentistry of Gazi University were examined by three observers and a supervisor, all of whom were blinded to patient gender and age. Axial, sagittal, and cross-sectional slices with a thickness of 1 mm were used. Numbers of roots and canals for each type of tooth were recorded. Most teeth had a single root and single root canal. Roots with two canals were more frequent in the incisors (14.9%, 17.2%, and 6.1% of the central incisors, lateral incisors, and canines, respectively). Teeth with two roots were more frequent in the canines (3.1% vs. 0% or 0.1%). Females more often had canines with double root canals (p < 0.001). When at least one tooth had two root canals, bilateral symmetry between contralateral teeth was found in 45.0%, 29.0%, and 28.0% of cases for central incisors, lateral incisors, and canines, respectively. Patients older than 56 years had fewer teeth with double root canals (p ≤ 0.001). A small proportion of the mandibular anterior teeth had two roots or root canals. Double root canals were mostly unilateral. Age and gender were associated with the number of root canals.

Root and canal symmetry in the mandibular anterior teeth of patients attending a dental clinic: CBCT study

The aims of this study were to evaluate the number of roots/root canals in the mandibular anterior teeth of a Turkish population, to assess the relationship between gender or age and the frequency of two canals in a single root, and to determine the symmetry in root/root canal numbers between contralateral sides among patients. Cone-beam computed tomography images (n = 1128; 6253 teeth) taken at the Department of Dentomaxillofacial Radiology of the Faculty of Dentistry of Gazi University were examined by three observers and a supervisor, all of whom were blinded to patient gender and age. Axial, sagittal, and cross-sectional slices with a thickness of 1 mm were used. Numbers of roots and canals for each type of tooth were recorded. Most teeth had a single root and single root canal. Roots with two canals were more frequent in the incisors (14.9%, 17.2%, and 6.1% of the central incisors, lateral incisors, and canines, respectively). Teeth with two roots were more frequent in the canines (3.1%vs. 0% or 0.1%). Females more often had canines with double root canals (p < 0.001). When at least one tooth had two root canals, bilateral symmetry between contralateral teeth was found in 45.0%, 29.0%, and 28.0% of cases for central incisors, lateral incisors, and canines, respectively. Patients older than 56 years had fewer teeth with double root canals (p ≤ 0.001). A small proportion of the mandibular anterior teeth had two roots or root canals. Double root canals were mostly unilateral. Age and gender were associated with the number of root canals.

Sealer penetration into dentinal tubules in the presence or absence of smear layer: a confocal laser scanning microscopic study.

INTRODUCTION: The aim of this study was to test the dentinal tubule penetration of AH26 (Dentsply DeTrey, Konstanz, Germany) and MTA Fillapex (Angelus, Londrina, PR, Brazil) in instrumented root canals obturated by using cold lateral compaction or warm vertical compaction techniques in either the presence or absence of the smear layer. METHODS: Forty-five extracted single-rooted human mandibular premolar teeth were used. The crowns were removed, and the root canals were instrumented by using the Self-Adjusting File (ReDent-Nova, Ra'anana, Israel) with continuous sodium hypochlorite (2.6%) irrigation. Final irrigation was either with 5% EDTA or with sodium hypochlorite. The canals were dried and obturated by using rhodamine B-labeled AH26 or MTA Fillapex in combination with the cold lateral compaction or the warm vertical compaction technique. After setting, the roots were sectioned horizontally at 4-, 8-, and 12-mm distances from the apical tip. On each section, sealer penetration in the dentinal tubules was measured by using confocal laser scanning microscopy. RESULTS: Regardless of the usage of EDTA, MTA Fillapex, compared with AH26, was associated with greater sealer penetration when used with the cold lateral compaction technique, and, conversely, AH26, compared with MTA Fillapex, was associated with greater sealer penetration when used with the warm vertical compaction technique (P < .05). Removal of the smear layer increased the penetration depth of MTA Fillapex used with the cold lateral compaction technique (P < .05); however, it had no significant effect on the penetration depth of AH26. CONCLUSIONS: Greater sealer penetration could be achieved with either the MTA Fillapex-cold lateral compaction combination or with the AH26-warm vertical compaction combination. Smear layer removal was critical for the penetration of MTA Fillapex; however, the same did not hold for AH26.

Antibacterial activity of various root canal sealers and root-end filling materials in dentin blocks infected ex vivo with Enterococcus faecalis.

OBJECTIVE: The aim was to investigate the antibacterial activity of the root-end filling materials MTA and IRM, different endodontic sealers and calcium hydroxide [Ca(OH)2] in experimentally infected dentinal tubules. MATERIALS AND METHODS: Ninety-four human root segments were prepared and the root canals were enlarged to ISO size 90. After smear removal, the specimens were infected with Enterococcus faecalis for 3 weeks. The roots were divided into eight groups and filled either with MTA, IRM, Ca(OH)2, gutta-percha and EndoRez (ER)/GuttaFlow (GF)/AH Plus (AH+) or with Resilon and Epiphany (EpRe). One group of specimens was left unfilled for control. Half of the specimens were treated for 1 day and the other half for 7 days in humid conditions at 37°C. Dentin samples from each canal were collected by enlarging the canals to ISO size 150; thus a dentinal depth of 300 µm was sampled. The number of cultivable bacteria was determined for each specimen. Statistical significance was set to 5%. RESULTS: After 1-day or 7-days of treatment, compared to control, all materials (except ER and GF at day 7) significantly reduced the number of bacteria. At day 1 and day 7, no significant difference was found between ER and GF and between Ca(OH)2, AH+, EpRe, IRM and MTA. However, a significant difference was found between these two groups of materials (except between GF and EpRe at day 7). Significantly more bacteria were cultured in the ER, GF, EpRe and IRM groups at day 7 compared to day 1. CONCLUSIONS: All materials exerted varying degrees of antibacterial activity which generally tended to decrease with time. The most stable antibacterial effect throughout the 7-day period was for Ca(OH)2, AH+ and MTA.

Evaluation of three instrumentation techniques at the precision of apical stop and apical sealing of obturation

OBJECTIVE: The aim of this study was to investigate the ability of two NiTi rotary apical preparation techniques used with an electronic apex locator-integrated endodontic motor and a manual technique to create an apical stop at a predetermined level (0.5 mm short of the apical foramen) in teeth with disrupted apical constriction, and to evaluate microleakage following obturation in such prepared teeth. MATERIAL AND METHODS: 85 intact human mandibular permanent incisors with single root canal were accessed and the apical constriction was disrupted using a #25 K-file. The teeth were embedded in alginate and instrumented to #40 using rotary Lightspeed or S-Apex techniques or stainless-steel K-files. Distance between the apical foramen and the created apical stop was measured to an accuracy of 0.01 mm. In another set of instrumented teeth, root canals were obturated using gutta-percha and sealer, and leakage was tested at 1 week and 3 months using a fluid filtration device. RESULTS: All techniques performed slightly short of the predetermined level. Closest preparation to the predetermined level was with the manual technique and the farthest was with S-Apex. A significant difference was found between the performances of these two techniques (p<0.05). Lightspeed ranked in between. Leakage was similar for all techniques at either period. However, all groups leaked significantly more at 3 months compared to 1 week (p<0.05). CONCLUSIONS: Despite statistically significant differences found among the techniques, deviations from the predetermined level were small and clinically acceptable for all techniques. Leakage following obturation was comparable in all groups.

Evaluation of three instrumentation techniques at the precision of apical stop and apical sealing of obturation.

OBJECTIVE: The aim of this study was to investigate the ability of two NiTi rotary apical preparation techniques used with an electronic apex locator-integrated endodontic motor and a manual technique to create an apical stop at a predetermined level (0.5 mm short of the apical foramen) in teeth with disrupted apical constriction, and to evaluate microleakage following obturation in such prepared teeth. MATERIAL AND METHODS: 85 intact human mandibular permanent incisors with single root canal were accessed and the apical constriction was disrupted using a #25 K-file. The teeth were embedded in alginate and instrumented to #40 using rotary Lightspeed or S-Apex techniques or stainless-steel K-files. Distance between the apical foramen and the created apical stop was measured to an accuracy of 0.01 mm. In another set of instrumented teeth, root canals were obturated using gutta-percha and sealer, and leakage was tested at 1 week and 3 months using a fluid filtration device. RESULTS: All techniques performed slightly short of the predetermined level. Closest preparation to the predetermined level was with the manual technique and the farthest was with S-Apex. A significant difference was found between the performances of these two techniques (p<0.05). Lightspeed ranked in between. Leakage was similar for all techniques at either period. However, all groups leaked significantly more at 3 months compared to 1 week (p<0.05). CONCLUSIONS: Despite statistically significant differences found among the techniques, deviations from the predetermined level were small and clinically acceptable for all techniques. Leakage following obturation was comparable in all groups.

Antibacterial activity of Propolis versus conventional endodontic disinfectants against Enterococcus faecalis in infected dentinal tubules.

INTRODUCTION: The antibacterial activity against Enterococcus faecalis of 2 propolis samples was investigated in a dentin block model, and their effectiveness was compared with that of established endodontic disinfectants, chlorhexidine (CHX) and calcium hydroxide [Ca(OH)(2)]. METHODS: Standardized dentin blocks were infected with E. faecalis ATCC 29212. The root canal space was filled with one of the ethanolic extracts of propolis (Artvin or Tekirdag mix [TM]), CHX 2%, Ca(OH)(2), or ethanol or phosphate-buffered saline for control. Canal dentin was sampled after 1 or 7 days by using a standard-size bur. The dentinal shavings were vortexed vigorously in phosphate-buffered saline, and aliquots were cultured on tryptone soy agar plates. Colonies were counted after 2 days of incubation. Statistical significance was set to 5%. RESULTS: All experimental agents significantly reduced the number of the cultivable bacteria. CHX was the most potent disinfectant at both times. Compared with the ethanol control, no significant reduction in the number of colonies was found for the propolis extracts at day 1; however, significant reduction was found at day 7. The 2 propolis samples were statistically similar to each other and to Ca(OH)(2), but the TM sample was also similar to CHX at day 7. This has been linked to the greater concentration of flavonoids, a group of antibacterially active compounds, in the TM sample as determined by gas chromatography-mass spectrometry analysis. CONCLUSIONS: The antimicrobial activity of the propolis samples tested in this study was between Ca(OH)(2) and CHX. Both propolis samples were antimicrobially effective; however, their activity did not exceed CHX.

Dental restoration dislodgment and fracture during scuba diving: a case of barotrauma.

BACKGROUND: The term "barotrauma" is used to describe a physical injury caused by a rapid or extreme change in air pressure. Enclosed areas within the body are particularly affected by barotrauma. CASE DESCRIPTION: A 40-year-old man had complaints of restorations in three teeth fracturing and dislodging while he was scuba diving at a depth of 35 meters. The affected teeth contained carious dentin. The caries was removed, and the affected teeth underwent endodontic, restorative and prosthetic rehabilitation. CLINICAL IMPLICATIONS: Inadequate restorations and selection of dental materials in some cases predispose patients to barotrauma. To prevent barotrauma-related damages on the teeth, it is important to maintain good-quality restorations and avoid trapping air beneath them. Dentists and patients who are exposed to barometric stress as part of their jobs or hobbies should know the causes of barotrauma and be aware of the importance of routine dental checkups to avoid barotrauma-related dental problems.

Examination of gutta-percha cones for microbial contamination during chemical use

OBJECTIVE: The aim of this study was to evaluate the degree of microbial contamination in packaged gutta-percha cones before and during use in clinical conditions. MATERIAL AND METHODS: Sealed packages of #15-40 gutta-percha cones were opened under aseptic laboratory conditions. Two gutta-percha cones from each size were randomly drawn and added to tubes containing glass beads and 750 µL of saline. The tubes were vortexed, serially diluted and samples of 250 µL were cultured on agar plates. The plates were incubated at 37ºC for 3 days and colonies were counted. The initially sampled packages were distributed to 12 final year dental students. The packages were collected at the end of the first and the third clinical practice days and sampled as described above. RESULTS: Baseline microbial counts did not exceed 3 CFU. At the end of the first and the third day, additional contamination was found in five and three of the packages, respectively. The ratio of contaminated packages at the first day and the third day was not significantly different (z-test; p > 0.05). The numbers of microorganisms cultured at the first day (8 ± 9.9 CFU) and the third day (4.5 ± 8.3 CFU) were not significantly different (Wilcoxon signed-rank test; p > 0.05). No significant correlation was found between the number of filled root canals and cultured microorganisms at either the first day (Spearman's rho; r = 0.481, p = 0.113) or the third day (r = -0.034, p = 0.917). CONCLUSIONS: Gutta-percha cones taken directly from manufacturer's sealed package harbored microorganisms. Clinical use of the packages has been found to be associated with additional contamination of the gutta-percha cones. The counts of cultured microorganisms did not correlate well with the number of filled root canals.

A case of Ekman-Westborg-Julin trait: endodontic treatment of a macrodontic incisor.

A case of Ekman-Westborg and Julin trait and endodontic treatment of a macrodontic lateral incisor with a necrotic pulp and periradicular pathosis presented in a 21-year-old woman. Clinical and radiological findings suggesting the Ekman-Westborg and Julin trait included multiple macrodontia, multituberculism, and single conical molar roots. Orthodontic problems such as mandibular prognatism and anterior and posterior cross-bite and other minor dental morphological changes were also found. Periradicular healing after endodontic treatment was followed by standardized periapical x-ray series, and signs of healing were observed at the 9 months postoperative control.

Examination of gutta-percha cones for microbial contamination during chemical use.

OBJECTIVE: The aim of this study was to evaluate the degree of microbial contamination in packaged gutta-percha cones before and during use in clinical conditions. MATERIAL AND METHODS: Sealed packages of #15-40 gutta-percha cones were opened under aseptic laboratory conditions. Two gutta-percha cones from each size were randomly drawn and added to tubes containing glass beads and 750 microL of saline. The tubes were vortexed, serially diluted and samples of 250 microL were cultured on agar plates. The plates were incubated at 37 degrees C for 3 days and colonies were counted. The initially sampled packages were distributed to 12 final year dental students. The packages were collected at the end of the first and the third clinical practice days and sampled as described above. RESULTS: Baseline microbial counts did not exceed 3 CFU. At the end of the first and the third day, additional contamination was found in five and three of the packages, respectively. The ratio of contaminated packages at the first day and the third day was not significantly different (z-test; p > 0.05). The numbers of microorganisms cultured at the first day (8 +/- 9.9 CFU) and the third day (4.5 +/- 8.3 CFU) were not significantly different (Wilcoxon signed-rank test; p > 0.05). No significant correlation was found between the number of filled root canals and cultured microorganisms at either the first day (Spearman's rho; r = 0.481, p = 0.113) or the third day (r = -0.034, p = 0.917). CONCLUSIONS: Gutta-percha cones taken directly from manufacturer's sealed package harbored microorganisms. Clinical use of the packages has been found to be associated with additional contamination of the gutta-percha cones. The counts of cultured microorganisms did not correlate well with the number of filled root canals.

The resistance of collagen-associated, planktonic cells of Enterococcus faecalis to calcium hydroxide.

This study examined whether collagen association by an endodontic isolate of Enterococcus faecalis conferred resistance to the bacterium against calcium hydroxide. E. faecalis A197A was grown at 46 degrees C until early stationary phase. Standardized bacterial suspensions were pretreated for 1 hour either with acid-soluble collagen or acidified phosphate-buffered saline (ac-PBS) and cultured to determine the baseline viable bacterial numbers. The bacterial suspensions were challenged with calcium hydroxide solution. Samples were removed at 6, 12, and 24 hours and cultured on tryptone soy agar plates. An adherence assay was performed to confirm that the collagen in the pretreatment medium was bound by the bacteria. Significantly more bacteria were cultivated at 12 hours in the collagen-pretreated group than the ac-PBS-pretreated group (p < 0.01). No bacteria could be cultivated at 24 hours in either group. Collagen association by E. faecalis A197A was found to increase the tolerance of the bacterium to calcium hydroxide.

Second mesiobuccal canal detection in maxillary first molars using microscopy and ultrasonics.

The aim of this study was to investigate whether the use of operating microscope in combination with ultrasonics increased the rate of second mesiobuccal (MB2) canal detection in permanent maxillary first molar teeth. A hundred extracted human maxillary first molars were assessed. After location of the main canals, the MB2 canal was sought in all teeth first without microscopy, then with the aid of the operating microscope and finally with the combined use of the operating microscope and ultrasonics. With these techniques, the MB2 canal was detected in 62%, 67% and 74% of the teeth, respectively. The combination of the operating microscope and ultrasonics detected significantly more MB2 canals than when no microscopy was utilized (P < 0.05). Sectioning of the roots disclosed the presence of the MB2 canal in 82% of the teeth. Twenty-nine per cent of the teeth had a separate MB2 canal orifice and separate apical foramina. The results of this study suggested that the combined use of the operating microscope and ultrasonics increased the detection of MB2 canals in maxillary first permanent molars.

Intraradicular splinting with endodontic instrument of horizontal root fracture--case report.

This case report describes the treatment of a horizontal mid-root-fractured incisor with an alternative fixation technique. As a result of clinical signs of pulpal necrosis, both the coronal and the apical root fragments were endodontically treated and obturated at single visit, and the fragments were stabilized internally through insertion of a stainless-steel endodontic file into the root canal. Four-year follow-up examination revealed satisfactory clinical and radiographic findings with hard tissue repair of the fracture line. This technique can be a quick remedy for patients with root-fractured tooth, especially for those who cannot make a second visit to the dental clinic.