Journal of Endodontics

Published by Elsevier
Online ISSN: 0099-2399
Publications
Article
The purpose of this investigation was to examine variability of gutta-percha (GP) cone tip diameter (D(0)) and taper among five different brands of #30, 0.04 GP cones (n = 15/brand). Mean percent D(0) difference from the manufacturer's reported (nominal) diameter of Maillefer (-15.42 +/- 7.16%) and Lexicon (-12.76 +/- 4.98%) were significantly different (p < or = 0.05) from Maxima (3.18 +/- 7.06%), Diadent (3.62 +/- 11.37%), and K(3) (7.27 +/- 7.84%), which were not significantly different from each other but exhibited diameters larger than the nominal diameter as indicated by positive values. Mean taper percent difference of Maxima (-3.00 +/- 3.80%) was significantly different (p < or = 0.05) from Lexicon (3.67 +/- 3.64%) and Maillefer (6.67 +/- 3.49%), with comparisons to Diadent (-0.17 +/- 6.37%) and K(3) (1.50 +/- 6.93%) not significantly different (p > 0.05) from each other or any other brand. Based on the evidence, there is significant variability between GP cone brands for both diameter and taper, with Maxima and Diadent, respectively, exhibiting the smallest mean difference from manufacturer's nominal tip diameter and taper. However, the high standard deviation values associated with most of the diameter and taper differences from nominal values also suggest high variability within individual brands.
 
Article
The purpose of this study was to compare the rates of separation of 0.04 taper nickel titanium (NiTi) rotary instruments using two different instrumentation techniques. Twenty sets of 0.04 taper Profile Series 29 rotary instruments, sizes 2 to 6 were used in the mesial (mandibular) or buccal (maxillary) canals of extracted human molars with a 20 to 30 degree root curvature according to the Schneider classification. The rotary instruments were used up to 20 times either with the crown-down technique recommended by the manufacturer or with a combination of preflaring with hand files in a passive step-back technique followed by rotary instrumentation. Statistical analysis of the data showed that the combination technique allowed more uses before separation compared with the crown-down technique recommended by the manufacturer p < 0.0001.
 
Article
This investigation examined the variability of tip diameter (D0) and taper measurements among four different brands of #30, 0.04 nickel-titanium (NiTi) rotary files (n=15/brand). With all brands, the mean percent D0 difference from the manufacturer's reported (nominal) diameter (Profile GT, 1.73+/-2.03%; Endo Sequence, 3.38+/-3.91%; K3, 4.56+/-2.36%; Profile, 6.13+/-4.07%) indicated that files tended to be larger than the nominal diameter. A 1-factor ANOVA and Tukey's post hoc test revealed a statistically significant difference (p<or=0.05) between Profile GT (smallest difference from nominal) and Profile (largest difference). The ANOVA also indicated no significant effect (p>0.05) of brand on the mean percent difference of the measured taper compared to the nominal taper with the majority of measurements at either 0.039 or 0.040 taper.
 
Article
The purpose of this in vitro study was to compare the extrusion of thermoplacticized gutta-percha in teeth instrumented with Profile 0.06 or Profile GT, and obturated with Thermafil Plus and Thermafil GT, respectively. A total of 120, extracted, human maxillary central incisors were divided into four equal groups. Group 1 was instrumented with Profile 0.06 and obturated with Thermafil Plus. Group 2 was instrumented with Profile 0.06 and obturated using warm vertical condensation (negative control). Group 3 was instrumented with Profile GT and obturated with Thermafil GT. Group 4 was instrumented with Profile GT and obturated like Group 2 (negative control). Extrusion was graded as present or absent. Results found 9 of 30 extruded for group 1, 1 of 30 for group 2, 15 of 30 for group 3, and 2 of 30 for group 4. The results suggest that, in vitro, Thermafil GT may be more prone to extruding gutta-percha past the apical foramen than Thermafil Plus.
 
Article
This study compared the taper variation among Profile, Guidance, and EndoSequence 0.06 tapered rotary files to current standards. Fifteen files of sizes 35, 40, and 45 from each manufacturer were evaluated for a total of 135 files. A digital image of the first 4 mm of each file was captured with light microscope at 22x, calibrated for 0.001-mm accuracy, and analyzed. The diameter of each file was measured at 1 and 4 mm, and the taper was calculated. Of the 3 file systems, 100% of the Profile files, 97.8% of the Guidance files, and 86.7% of the EndoSequence files fell within +/-0.02 taper. All file systems demonstrated variability within their groups. A series of chi(2) analyses indicated that manufacturers tend to produce Guidance and Profile tapers slightly under the ideal 0.06 taper (P < .05). The tapers of EndoSequence files were just as likely to be over or under the advertised 0.06 taper (P > .05).
 
Zones of Inhibition (mm)
Article
The purpose of this in vitro study was to determine whether the substitution of 0.12% chlorhexidine gluconate for sterile water as a mixing agent would enhance the antimicrobial activity of tooth-colored ProRoot mineral trioxide aggregate (MTA) against Actinomyces odontolyticus (ATCC17982), Fusobacterium nucleatum (ATCC2586), Streptococcus sanguis (ATCC10556), Enterococcus faecalis (ER3/2S), Escherichia coli (SM10lambdapir), Staphylococcus aureus (ATCC6538), Pseudomonas aeruginosa (UME), and Candida albicans (ATCC10261). Two wells of 5-mm diameter were made in triplicate agar plates inoculated with standardized suspensions of each microorganism. MTA (33 mg) mixed with chlorhexidine (12 microl) or sterile water (12 microl) was placed to fill each well. Plates were incubated at 37 degrees C as required for microbial growth. A blinded, independent observer measured zones of inhibition. All MTA samples inhibited microbial growth regardless of mixing agent. MTA/chlorhexidine showed significantly larger zones of inhibition (p < 0.0002, paired t test). In conclusion, substituting 0.12% chlorhexidine gluconate for water enhanced the antimicrobial activity of tooth-colored ProRoot MTA.
 
Article
This in vitro study used dye penetration to compare the sealing ability of white and gray mineral trioxide aggregate mixed with distilled water and 0.12% chlorhexidine gluconate when used as root-end filling materials. Ninety-six single-rooted human teeth were cleaned, shaped, and obturated with gutta-percha and AH26 root canal sealer. The apical 3 mm of each root was resected, and 3-mm deep root-end cavity preparations were made. The teeth were randomly divided into 4 experimental groups, each containing 20 teeth, and 2 negative and positive control groups, each containing 8 teeth. Root-end cavities in the experimental groups were filled with the experimental materials. After decoronation of the teeth and application of nail polish, the teeth were exposed to India ink for 72 hours and longitudinally sectioned, and the extent of dye penetration was measured with a stereomicroscope. Statistical analysis showed that there were no significant differences among the 4 experimental groups.
 
Article
Sodium hypochlorite irrigant is known to be toxic to periapical tissues. Chlorhexidine gluconate, a safer and effective antimicrobial irrigant, is not known to dissolve pulpal tissues. To obtain their optimal properties, their combined action within the root canal was evaluated. Ten single rooted nonvital anterior teeth were irrigated using either 2.5% sodium hypochlorite alone, 0.2% chlorhexidine gluconate alone, 2.5% sodium hypochlorite and 0.2% chlorhexidine gluconate combined within the root canal, or 0.9% saline, respectively. Microbiological samples for culture and Gram's staining were taken before and proceeding irrigation. This study indicates that the use of sodium hypochlorite and chlorhexidine gluconate combined within the root canal resulted in the greatest percentage reduction of postirrigant positive cultures. This may be due to formation of "chlorhexidine chloride," which increases the ionizing capacity of the chlorhexidine molecule. This reduction was significant compared to use of sodium hypochlorite alone but not significant compared to use of chlorhexidine gluconate alone.
 
Article
The present study aimed to evaluate whether the association between a calcium hydroxide paste (Calen paste) and 0.4% chlorhexidine (CHX) affects the development of the osteogenic phenotype in vitro. With rat calvarial osteogenic cell cultures, the following parameters were assayed: cell morphology and viability, alkaline phosphatase activity, total protein content, bone sialoprotein immunolocalization, and mineralized nodule formation. Comparisons were carried out by using the nonparametric Kruskal-Wallis test (level of significance, 5%). The results showed that the association between Calen paste and 0.4% CHX did not affect the development of the osteogenic phenotype. No significant changes were observed in terms of cell shape, cell viability, alkaline phosphatase activity, and the total amount of bone-like nodule formation among control, Calen, or Calen + CHX groups. The strategy to combine Ca(OH)(2) and CHX to promote a desirable synergistic antibacterial effect during endodontic treatment in vivo might not significantly affect osteoblastic cell biology.
 
Article
The purpose of these 2 prospective, randomized, single-blind studies was to determine the anesthetic efficacy of lidocaine with epinephrine compared with a combination lidocaine with epinephrine plus 0.5 mol/L mannitol for inferior alveolar nerve (IAN) blocks in patients experiencing symptomatic irreversible pulpitis. In study one, 55 emergency patients randomly received IAN blocks by using a 3.18-mL formulation containing 63.6 mg of lidocaine with 31.8 μg epinephrine or a 5-mL formulation containing 63.6 mg of lidocaine with 31.8 μg epinephrine (3.18 mL) plus 1.82 mL of 0.5 mol/L mannitol. In study two, 51 emergency patients randomly received IAN blocks by using a 1.9-mL formulation containing 76.4 mg of lidocaine with 36 μg epinephrine or a 3-mL formulation containing 76.4 mg of lidocaine with 36 μg epinephrine (1.9 mL) plus 1.1 mL of 0.5 mol/L mannitol. Endodontic access was begun 15 minutes after the IAN block, and all patients had profound lip numbness. Success was defined as no or mild pain (visual analogue scale recordings) on endodontic access or instrumentation. The 1.9 mL of lidocaine (76.4 mg) with epinephrine plus 0.5 mol/L mannitol had a significantly (P = .04) better success rate of 39% when compared with the lidocaine formulation without mannitol (13% success rate). For mandibular posterior teeth in patients with symptomatic irreversible pulpitis, the addition of 0.5 mol/L mannitol to 1.9 mL of lidocaine (76.4 mg) with epinephrine resulted in a statistically higher success rate. However, the combination lidocaine/mannitol formulation would not result in predictable pulpal anesthesia.
 
Article
A measuring instrument must be both accurate and reliable. This study compared the reliability of the "0.5" and "APEX" mark measurements by using 2 impedance quotient-based electronic apex locators (EALs). One hundred four extracted human premolars were used in this study. After access preparation, the teeth were embedded in an alginate model. By using 2 EALs (Root ZX and i-Root), the tooth length was measured at the "0.5" and "APEX" marks with K-files. The file was then cemented, and the apical 3-4 mm was trimmed for the photograph under an operating microscope. The distance between the tip of the file and major foramen (MF) was measured. The intraclass correlation coefficient, the Bland-Altman plot, and box plot were used to compare the reliability. The intraclass correlation coefficient ranged from 0.976-0.994, indicating excellent agreement in both "0.5" and "APEX" marks. The Bland-Altman plots showed that the limits of agreement (mean ± 2 standard deviations) were small enough to confirm that both marks of the 2 EALs can be used for clinical purposes. The distribution of the measurements and outliers was analyzed by using box plots, and it was found that there was no significant difference between the 2 marks. There was no significant difference in the reliability of the "0.5" and "APEX" marks for locating the MF in both devices. Accordingly, knowing where each mark indicates is more important for determining the working length than which mark to choose.
 
Article
The purpose of this study was to compare the initial penetration depth of fine-fine nickel-titanium (NiTi) and fine-fine stainless-steel (SS) spreaders during lateral compaction of .02 or .04 tapered master gutta-percha cones and to evaluate the effect of increasing canal curvature on penetration depth. Fifty-one root canals were instrumented to a standardized size and grouped by degree of curvature for comparison. Our results showed that NiTi spreaders penetrated to a significantly greater depth than SS spreaders using .02 tapered gutta-percha in canal curvatures greater than 20 degrees and when using .04 tapered gutta-percha regardless of canal curvature. No significant difference occurred between NiTi and SS-spreader penetration using .02 tapered gutta-percha in canal curvatures of 0 to 20 degrees (p > 0.05). Both NiTi and SS spreaders penetrated to a greater depth as canal curvatures increased to greater than 20 degrees (p < 0.05). Both NiTi and SS spreaders penetrated to a shallower depth with .04 tapered gutta-percha compared with .02 tapered gutta-percha (p < 0.0001).
 
Article
The purpose of this in vitro study was to compare the quality of the seal in canals prepared in a standardized manner and obturated with a .06 or a .02 tapered gutta-percha master cone using lateral condensation. Forty-four extracted human anterior teeth with single, straight canals were divided into two experimental groups of 20 teeth each and two control groups of 2 teeth each. The teeth were instrumented with Series 29 Profile .06 tapered rotary nickel-titanium files to a master apical file of 0.46 mm. Teeth in group 1 were obturated with a .02 tapered master gutta-percha cone and Roth 801 sealer using lateral condensation. Teeth in group 2 were obturated similarly, except a .06 tapered master gutta-percha cone was used. The depth of spreader penetration was recorded in millimeters. Positive control teeth were instrumented but not filled. Negative control teeth were instrumented, obturated, and externally sealed. The teeth were placed into a coronal leakage apparatus that contained an upper and lower reservoir of trypticase soy broth separated by the tooth. A 24-h growth of Proteus vulgaris in 0.25 ml of trypticase soy broth was placed in the coronal reservoir every 7 days for 70 days and incubated at 37 degrees C. Student's t test was used to determine whether there was a difference in spreader penetration between the groups, and a Fisher's exact test was used to determine whether there was a difference in bacterial leakage. The positive and negative controls validated the testing model. When a .02 tapered master cone was used, the spreader penetrated significantly closer to working length than when a .06 tapered master cone was used (p < 0.05). The difference between the groups in the number of samples that demonstrated complete bacterial penetration was not significant (p > 0.05).
 
Article
ProFile 25/.04 instruments manufactured from three variants of Nitinol (1A, 1B & 2AS) were compared with stock production ProFile 25/.04 instruments and fatigue tested to failure. Cyclic fatigue testing was performed by rotating instruments at 300 RPM in a simulated steel root canal with 5 mm radius and 90 degrees curve until instrument separation. Time to failure was recorded. Torsion testing was undertaken by clamping 3 mm of each instrument tip between brass plates and rotating it at 2 RPM until failure. Data were recorded for torque and angle at fracture. Statistical differences were found with nickel-titanium variant 1B (M-Wire NiTi) nearly 400% more resistant to cyclic fatigue than stock ProFile 25/.04 (P < .001). Torsion testing found differences between all 508 Nitinol groups and M-Wire NiTi (P < .001). ProFile 25/.04 files manufactured from M-Wire NiTi have significantly greater resistance to cyclic fatigue while maintaining comparable torsional properties.
 
Article
The purposes of this study were to determine quantitatively the amount of debris and irrigant forced in an apical direction, the frequency of apical plug development, and the time required to prepare canals when a step-back technique using K-files was compared with the .04 Taper system. Sixty-nine extracted teeth with straight canals were divided into four statistically similar groups. Two groups were instrumented either 1 mm short of the apical foramen or to the apical foramen with K-files. The other two groups were instrumented to the same levels using .04 Taper files. The extruded debris and irrigant were collected in preweighed vials. The weight of the debris and volume of irrigant extruded using both techniques were compared and analyzed using paired t test and one-way ANOVA. Tukey's Multiple Comparisons Procedure showed K-files used to the apical foramen extruded significantly more debris than the other three groups (p < 0.01). The .04 Taper files used 1 mm short extruded less debris than the other groups. Significantly more irrigant was extruded when filing was performed to the apical foramen (p < 0.007), regardless of the technique used. More apical plugs were created in teeth filed short of the apical foramen, but the difference between the two preparation techniques was not statistically significant. It took significantly less time to instrument canals with the .04 Taper system than with K-files (p < 0.002).
 
Article
This study determined if the cleaning efficiency of nickel-titanium rotary files in an endodontic electric handpiece using a no-torque control setting was superior to that obtained when using the torque-control feature. Fifty extracted human anterior teeth with straight canals were divided into two groups of 20 and two control groups of 5. Canals were instrumented with GT and .04 ProFile nickel-titanium files until a size 35 advanced to working length. Samples were sectioned and the apical 6 mm of the canal was photographed (x20) and projected onto a 3- x 4-foot grid with squares measuring 0.5 inches each. Total debris was the percentage of the number of squares containing debris versus the total number of squares. The teeth in the torque-controlled group showed an average of 24.99% debris versus 15.55% for the teeth in the no-torque group. The difference was not statistically significant; therefore, no difference can be said to exist between the two torque settings in terms of cleaning efficiency.
 
Article
This study investigated the retreatment effectiveness of .04 Taper nickel-titanium rotary ProFiles. Thirty extracted single-rooted anterior teeth were instrumented and obturated with gutta-percha/Roth's Sealer using lateral condensation. They were distributed into three groups of 10 each. Retreatment for group A was done using Profile alone, group B using Profile and chloroform, and group C using hand files with chloroform. The teeth were then split longitudinally into halves. The remaining gutta-percha/sealer on the root canal wall in the cervical, middle, apical thirds, and the whole canals were visually scored with the aid of light microscopes. The results showed that the mean scores in groups A and B were generally lower (better) than group C. Mean scores of the apical thirds tended to be higher (worse) than the middle and the cervical thirds, except in group A. ProFile with or without chloroform seemed to be a viable alternative retreatment method.
 
Article
M-Wire (Sportswire LLC, Langley, OK) is reportedly created by altering alloy temperatures during the manufacturing process of GT series X instruments (Dentsply Tulsa Dental Specialties, Tulsa, OK). Currently, there are few published studies looking at torsional profiles of these instruments. The purpose of this study was to investigate the torsional profiles of new and used 20/0.06 GT series X (GTX) and GT (GT) instruments (Dentsply Tulsa Dental Specialties). Thirty instruments were allocated to one of eight groups and were used 2, 6, or 10 times in simulated canals or remained as unused controls. Testing of torque (TF) and angle at fracture (AF) were conducted in accordance with American National Standards Institute/American Dental Association (ANSI/ADA) specification No. 28. Data analyses were performed by using one- and two- way analysis of variance with honesty significance difference post hoc comparison with alpha = 0.05. Overall, there were significant differences in TF and AF among the experimental groups (p < 0.001). GTX instruments showed a significant initial increase in TF with two and six uses (p < 0.001) in contrast to the GT, which showed a linear reduction in TF with increased use (p < 0.004). Both GTX and GT instruments showed no statistical difference in AF of new instruments but did show a significant decrease in AF in all groups except the GT two-use group (p < 0.02). The GTX instruments had a higher resistance to torsional failure after use as compared with the GT.
 
Article
A study of 1,200 teeth was carried out in order to determine the occurrence of four-rooted maxillary second molars. One-thousand untreated teeth were examined radiographically. Two-hundred teeth were evaluated radiographically following endodontic treatment. The results indicated that only 0.4% of the teeth presented with four separate roots. Endodontic therapy in such a tooth is described.
 
Article
The effects of parathyroid hormone (PTH), 1,25-dihydroxyvitamin D3, and prostaglandin E2 (PGE2) on alkaline phosphatase activity on cultured dental pulp and gingiva cells of bovine calf were compared. In pulp cells, PTH, 1,25-dihydroxyvitamin D3, and PGE2 significantly increased alkaline phosphatase activity, but no increase in the enzyme activity by these factors was observed in gingiva cells. Dibutyryl cAMP also increased alkaline phosphatase activity in both types of cell, but the increase in pulp cells was greater than that in gingiva cells. Treatment of the cultured pulp cells with PTH or PGE2 significantly increased the intracellular cAMP content. These results suggest that calciotropic factors such as PTH, 1,25-dihydroxyvitamin D3, and PGE2 may be involved in the differentiation of dental pulp cells and that some of these effects (those of PTH and PGE2) are mediated by cAMP.
 
Article
We studied the possibility of the clinical use of a calcium phosphate-type newly developed sealer composed of tetracalcium phosphate, dicalcium phosphate dihydrate, and a modified McIlvain's buffer solution (TDM). Another sealer using the buffer solution, to which 2.5% chondroitin sulfate was added to promote wound healing (TDM-S), was also studied. TDM and TDM-S were histopathologically compared with another type of calcium phosphate sealer (ARS), which is commercially available in Japan, in the dorsal subcutaneous tissue and in the periapical tissue of rats. TDM and TDM-S caused no inflammatory reactions in the subcutaneous tissue. The periapical tissue reacted mildly to them. ARS caused severe inflammatory reactions in both the subcutaneous and the periapical tissue. These results indicate that TDM-S has excellent histocompatibility and potential as a root canal sealer.
 
Article
The purpose of this study was to compare the antimicrobial efficacy of 1.3% NaOCl/BioPure MTAD to 5.25% NaOCl/15% EDTA for root canal irrigation. Twenty-six bilaterally matched pairs of human teeth were collected. The teeth were incubated with Enterococcus faecalis for 4 weeks. The teeth were divided into two experimental groups and one positive control group. The canals were instrumented and irrigated with either 5.25% NaOCl/15% EDTA or 1.3% NaOCl/BioPure MTAD. Bacterial samples were collected after instrumentation/irrigation and after additional canal enlargement. Statistical analysis of the data using the Wilcoxon Signed Rank test showed significant differences between the experimental groups. The first bacterial samples revealed growth in 0 of 20 samples with 5.25% NaOCl/15% EDTA irrigation and in 8 of 20 samples with 1.3% NaOCl/BioPure MTAD irrigation. Samples taken after additional canal enlargement revealed growth in 0 of 20 samples in 5.25% NaOCl/15% EDTA and in 10 of 20 samples in 1.3% NaOCl/BioPure MTAD group. This investigation showed consistent disinfection of infected root canals with 5.25% NaOCl/15% EDTA. The combination of 1.3% NaOCl/BioPure MTAD left nearly 50% of the canals contaminated with E. faecalis.
 
Article
The purpose of this prospective, randomized, single-blinded study was to measure the degree of anesthesia obtained with 1.8 mL and 3.6 mL of 2% lidocaine with 1:100,000 epinephrine in posterior superior alveolar (PSA) nerve blocks. Thirty-one adult subjects randomly received PSA nerve blocks of 1.8 mL and 3.6 mL of the lidocaine solution at 2 separate appointments in a crossover design. An electric pulp tester was used to test for anesthesia of the first and second molars and premolars in 3-minute cycles for 50 minutes. Anesthesia was considered successful when 2 consecutive 80 readings were obtained within 15 minutes. Anesthetic success for the 1.8 mL volume of 2% lidocaine with 1:100,000 epinephrine was 97% for the second molar and 77% for the first molar. Anesthetic success for the 3.6 mL volume of 2% lidocaine with 1:100,000 epinephrine was 100% for the second molar and 84% for the first molar. The differences were not statistically significant between the 2 anesthetic volumes. Anesthetic success for the premolars for both volumes was in the low to moderate range and would not provide predictable pulpal anesthesia. For the first molar, the 3.6 mL volume of the lidocaine formulation provided a statistically longer duration of pulpal anesthesia than the 1.8 mL volume. The pain of depositing a 3.6 mL volume of a lidocaine solution was not statistically more painful than depositing a 1.8 mL volume.
 
Article
The purpose of this retrospective study was to determine the success of the inferior alveolar nerve (IAN) block using either 3.6 mL or 1.8 mL 2% lidocaine with 1:100,000 epinephrine in patients presenting with symptomatic irreversible pulpitis. As part of 7 previously published studies, 319 emergency patients presenting with symptomatic irreversible pulpitis received either a 1.8-mL volume or 3.6-mL volume of 2% lidocaine with 1:100,000 epinephrine in an IAN block. One hundred ninety patients received a 1.8-mL volume, and 129 received a 3.6-mL volume. Endodontic emergency treatment was completed on each subject. Success was defined as the ability to access and instrument the tooth without pain (visual analog scale score of 0) or mild pain (VAS rating ≤54 mm). Success of the 1.8-mL volume was 28%, and for the 3.6-mL volume it was 39%. There was no statistically significant difference between the 2 volumes. In conclusion, for patients presenting with irreversible pulpitis, success was not significantly different between a 3.6-mL volume and a 1.8-mL volume of 2% lidocaine with 1:100,000 epinephrine. The success rates (28%-39%) with either volume were not high enough to ensure complete pulpal anesthesia.
 
Article
There is a decrease in the anesthetic efficacy of inferior alveolar nerve blocks in patients with irreversible pulpitis. It was hypothesized that the increasing the volume of anesthetic solution may improve the success rates of dental pulp anesthesia in patients with pulpal pain. Fifty-five adult volunteers, actively experiencing pain, participated in this prospective, randomized, single-blind study. The patients were divided into 2 groups on a random basis and received an inferior alveolar nerve block with either 1.8 mL or 3.6 mL of 2% lidocaine with 1:200,000 epinephrine. Endodontic access preparation was initiated after 15 minutes of the initial IANB. Pain during treatment was recorded using the Heft-Parker visual analog scale (HP VAS). The primary outcome measure, and the definition of "success," was the ability to undertake pulp access and canal instrumentation with no or mild pain (HP VAS score <55 mm). Statistical analysis was performed using the chi-square test. All patients included in the final analysis had profound lip anesthesia. There were no significant differences in sex, age, or preoperative pain scores of the experimental groups. IANBs of 1.8 mL lidocaine with epinephrine had a success rate of 26%, whereas the administration of 3.6 mL had a 54% success rate. The difference was statistically significant. Increasing the volume of 2% lidocaine to 3.6 mL improved the success rate as compared with 1.8 mL but did not give a clinical success rates of 100%.
 
Article
The purpose of this prospective, randomized, single-blinded study was to measure the degree of anesthesia obtained with 1.8 mL and 3.6 mL of 2% lidocaine with 1:100,000 epinephrine in maxillary infiltrations. Ninety-six adult subjects randomly received infiltrations of 1.8 mL and 3.6 mL of the lidocaine solution at two separate appointments, in a crossover design. Thirty-two lateral incisors, 32 first premolars and 32 first molars were studied in this investigation. Anesthetic success (obtaining two consecutive 80 readings with the electric pulp tester) for the two volumes ranged from 97% to 100%. The onset of pulpal anesthesia was not statistically different between the two volumes. For both volumes, the lateral incisors had a higher percentage of anesthesia of short duration than the first premolar and first molar. The 3.6 mL volume provided a statistically longer duration of pulpal anesthesia for the lateral incisor, first premolar, and first molar.
 
Article
No study has compared 1.8 mL and 3.6 mL 4% articaine with 1:100,000 epinephrine in a mandibular buccal infiltration of the first molar. The authors conducted a prospective, randomized, single-blind, crossover study comparing the degree of pulpal anesthesia obtained with 1.8 mL and 3.6 mL 4% articaine with 1:100,000 epinephrine as a primary infiltration in the mandibular first molar. Eighty-six asymptomatic adult subjects randomly received a primary mandibular buccal first molar infiltration of 1.8 mL or 3.6 mL 4% articaine with 1:100,000 epinephrine in two separate appointments. The authors used an electric pulp tester to test the first molar for anesthesia in 3-minute cycles for 90 minutes after the injections. Compared with the 1.8-mL volume of 4% articaine with 1:100,000 epinephrine, the 3.6-mL volume showed a statistically higher success rate (70% vs 50%). The anesthetic efficacy of 3.6 mL 4% articaine with 1:100,000 epinephrine is better than 1.8 mL of the same anesthetic solution in a primary mandibular buccal infiltration of the first molar. However, the success rate of 70% is not high enough to support its use as a primary injection technique in the mandibular first molar.
 
Article
The purpose of this prospective, randomized study was to compare the degree of pulpal anesthesia obtained in vital, asymptomatic teeth by using 1.8 mL and 3.6 mL of 2% lidocaine with 1:50,000 epinephrine compared with 1.8 mL of 2% lidocaine with 1:100,000 epinephrine for inferior alveolar nerve (IAN) block. Thirty adult subjects randomly received IAN blocks of 1.8 mL and 3.6 mL of 2% lidocaine with 1:50,000 epinephrine and 1.8 mL of 2% lidocaine with 1:100,000 epinephrine at 3 separate appointments in a crossover design. An electric pulp tester was used to test for anesthesia in 3-minute cycles for 60 minutes of the first molars, first premolars, and lateral incisors. Anesthesia was considered successful when 2 consecutive 80 readings were obtained within 15 minutes, and the 80 reading was continuously sustained through the 60th minute. By using 1.8 mL of 2% lidocaine with 1:50,000 epinephrine, successful pulpal anesthesia ranged from 33%-50%, and when using 3.6 mL of 2% lidocaine with 1:50,000 epinephrine, success ranged from 40%-60%. When using 1.8 mL of 2% lidocaine with 1:100,000 epinephrine, success ranged from 40%-60%, with no significant difference among the 3 anesthetic formulations. Increasing the epinephrine concentration to 1:50,000 epinephrine or increasing the volume to 3.6 mL of 2% lidocaine with 1:50,000 epinephrine did not result in more successful pulpal anesthesia when compared with 1.8 mL of 2% lidocaine with 1:100,000 epinephrine by using the IAN block.
 
Article
Local anesthetics can be buffered to a physiological pH before injection to decrease the time of onset and reduce injection pain. Thirty subjects with intact maxillary canines were included. The subjects randomly received, in a double-blind manner, 1 of the 3 maxillary infiltration injections of 1.8 mL 2% lidocaine with 1:100,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine buffered at 5% and 10% with sodium bicarbonate by volume at 3 separate appointments. Pain on needle penetration and deposition of anesthetic solution was recorded by using a Heft-Parker visual analogue scale. Anesthetic onset was determined by 2 consecutive negative responses to electronic pulp test. The mean anesthetic onset for nonbuffered anesthetics was 119 seconds, 116 seconds for the 5% buffered solutions, and 121 seconds for the 10% buffered solutions. There was no significant difference between the 3 groups. There was also no significant difference in pain on needle penetration or anesthetic deposition between the 3 anesthetic solutions tested. Two percent lidocaine with 1:100,000 epinephrine buffered with 5% or 10% sodium bicarbonate did not differ from nonbuffered solutions in anesthetic onset or injection pain in maxillary infiltrations of canines with healthy pulps.
 
Article
The purpose of this prospective, randomized, double-blind study was to compare the anesthetic efficacy of 2% lidocaine with 1:100,000 epinephrine and 3% mepivacaine in the maxillary high tuberosity second division nerve block. Fifty subjects randomly received maxillary high tuberosity second division nerve blocks by using 3.6 mL of 2% lidocaine with 1:100,000 epinephrine and 3.6 mL of 3% mepivacaine at 2 separate appointments spaced at least 1 week apart. The anterior, premolar, and molar teeth were pulp tested in 4-minute cycles for a total of 60 minutes. Success was defined as no subject response to 2 consecutive 80 readings with the electric pulp tester. The high tuberosity approach to the maxillary second division nerve block with both anesthetic formulations resulted in a high success rate (92%-98%) for the first and second molars. Approximately 76%-78% of the second premolars were anesthetized with both anesthetic formulations. Both anesthetic formulations were ineffective for the anterior teeth and first premolars. The use of 3% mepivacaine provided a significantly shorter duration of pulpal anesthesia than 2% lidocaine with 1:100,000 epinephrine in the molars and premolars.
 
Article
The purpose of this study was to evaluate, with an electric pulp tester, the anesthetic efficacy of the periodontal ligament injection. Two percent lidocaine, 3% mepivacaine, and 1:100,000 epinephrine were compared with 2% lidocaine with 1:100,000 epinephrine in human mandibular premolars. Two percent lidocaine with 1:100,000 epinephrine anesthetized significantly more first premolars (87% success), for a longer duration (approximately 20 min), than any of the test solutions. Three percent mepivacaine anesthetized 42% of the teeth and, had a duration of approximately 4 min. Two percent lidocaine anesthetized 14% of the teeth and had a duration of 2 to 4 min. The epinephrine solution did not anesthetize any teeth. Two percent lidocaine with epinephrine anesthetized more adjacent teeth, both mesial (45% success rate) and distal (78% success rate), for a longer duration than any of the test solutions. Initial needle penetrations and injections of 2% lidocaine with epinephrine, in clinically healthy teeth, were only mildly discomforting. Postinjection discomfort was experienced by 88% of the subjects and 49% reported that their tooth felt high in occlusion. No clinically observable pulpal or periodontal damage was seen at 4 wk postinjection.
 
Article
The purpose of this study was to determine the anesthetic efficacy of a supplemental intraosseous injection of 2% lidocaine with 1:100,000 epinephrine in teeth diagnosed with irreversible pulpitis. Fifty-one patients with symptomatic, vital maxillary, and mandibular posterior teeth diagnosed with irreversible pulpitis received conventional infiltrations or inferior alveolar nerve blocks. Pulp testing was used to determine pulpal anesthesia after "clinically successful" injections. Patients who were positive to the pulp tests, or were negative to the pulp tests but felt pain during endodontic access, received an intraosseous injection using 1.8 ml of 2% lidocaine with 1:100,000 epinephrine. The results demonstrated that 42% of the patients who tested negative to the pulp tests reported pain during treatment and required supplemental anesthesia. Eighty-one percent of the mandibular teeth and 12% of maxillary teeth required an intraosseous injection due to failure to gain pulpal anesthesia. Overall, the Stabident intraosseous injection was found to be 88% successful in gaining total pulpal anesthesia for endodontic therapy. We concluded that, for posterior teeth diagnosed with irreversible pulpitis, the supplemental intraosseous injection of 2% lidocaine (1:100,000 epinephrine) was successful when conventional techniques failed.
 
Article
The purpose of this prospective, randomized, double-blind crossover study was to evaluate the anesthetic efficacy of 2% lidocaine with 1:100,000 and 1:50,000 epinephrine and 3% mepivacaine in maxillary lateral incisors and first molars. Sixty subjects randomly received, in a double-blind manner, maxillary lateral incisor and first molar infiltrations of 1.8 mL of 2% lidocaine with 1:100,000 epinephrine, 2% lidocaine with 1:50,000 epinephrine, and 3% mepivacaine at three separate appointments spaced at least 1 week apart. The teeth were pulp tested in 3-minute cycles for a total of 60 minutes. Anesthetic success and the onset of pulpal anesthesia were not significantly different between 2% lidocaine with either 1:100,000 or 1:50,000 epinephrine and 3% mepivacaine for the lateral incisor and first molar. Increasing the epinephrine concentration from 1:100,000 to 1:50,000 in a 2% lidocaine formulation significantly decreased pulpal anesthesia of short duration for the lateral incisor but not the first molar. For both the lateral incisor and first molar, 3% mepivacaine significantly increased pulpal anesthesia of short duration compared with 2% lidocaine with either 1:100,000 or 1:50,000 epinephrine.
 
Article
The purpose of this prospective, randomized, double-blind study was to compare the anesthetic efficacy of 2% lidocaine with 1:100,000 epinephrine, 2% lidocaine with 1:50,000 epinephrine, and 3% mepivacaine in the intraoral, infraorbital nerve block. Forty subjects randomly received intraoral, infraorbital nerve blocks by using a cartridge of 2% lidocaine with 1:100,000 or 1:50,000 epinephrine and a cartridge of 3% mepivacaine at 3 separate appointments spaced at least 1 week apart. The anteriors, premolars, and first molar were pulp tested in 4-minute cycles for a total of 60 minutes. The intraoral, infraorbital nerve block was ineffective in providing profound pulpal anesthesia of the maxillary central incisor, lateral incisor, and first molar. Successful pulpal anesthesia of the canine and first and second premolars ranged from 75%-92% by using 2% lidocaine with 1:100,000 and 1:50,000 epinephrine. However, pulpal anesthesia did not last for 60 minutes. The use of 3% mepivacaine provided a shorter duration of anesthesia than the lidocaine formulations with epinephrine in the canines and premolars.
 
Article
The purpose of this prospective, randomized study was to compare the venous blood levels of lidocaine and heart rate changes after intraosseous and infiltration injections of 1.8 ml of 2% lidocaine with 1:100,000 epinephrine. Using a crossover design, 20 subjects randomly received an intraosseous and infiltration injection at two separate appointments. The heart rate was measured using a pulse oximeter. Venous blood samples were collected before the injections and at 2, 5, 10, 15, 20, 25, 30, 45, and 60 min after the injections. The blinded plasma samples were analyzed for lidocaine concentrations using high-performance liquid chromatography (HPLC). The intraosseous injection resulted in a statistically significant increase in heart rate, when compared to the infiltration injection, during solution deposition and for 2 min after the injection. The plasma levels of lidocaine were not statistically different for maxillary anterior intraosseous and infiltration injections when using 1.8 ml of 2% lidocaine with 1:100,000 epinephrine.
 
Article
To assess the efficacy of buccal infiltrations of 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:80,000 epinephrine in achieving anesthesia in maxillary teeth with irreversible pulpitis. This randomized double-blind clinical trial included 100 patients diagnosed with irreversible pulpitis in maxillary teeth. Patients received 2.0 mL 4% articaine with 1:100,000 epinephrine or 2% lidocaine with 1:80,000 epinephrine in the buccal sulcus adjacent to the tooth with pulpitis. Before and every 2 minutes up to a maximum of 10 minutes after injection, the response of the test tooth was assessed using an electronic pulp tester. Successful pulp anesthesia was considered to have occurred when no response was obtained to the maximum stimulation (80 reading) of the pulp tester during the test period, at which time treatment commenced. Treatment was regarded as being successfully completed when it was associated with no pain. The time to onset of successful pulp anesthesia was recorded for each test tooth. Injection discomfort was recorded on standard 100-mm visual analog scales (VASs). Data were analyzed by the Chi-square and Student t tests. Fifty patients received articaine and 50 received lidocaine. Seventy-three of the 100 patients achieved pulpal anesthesia within 10 minutes of injection: 38 after articaine and 35 after lidocaine (P = .5). The onset of pulpal anesthesia after articaine and lidocaine buccal infiltrations was similar (mean and standard deviations: 4.9 ± 2.7 minutes vs 5.1 ± 2.4 minutes, respectively; t = 0.2; P = .82). Pain-free treatment was completed in 33 patients after articaine and 29 after lidocaine buccal infiltrations (P = .63). Although articaine buccal injection was significantly more comfortable than lidocaine buccal injection (t = 2.3, P = .026), both were associated with mild discomfort on VAS (means ± standard deviation: 10.8 mm ± 11.7 mm vs 17.5 mm ± 17.6 mm, respectively). There was no significant difference in efficacy between 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:80,000 epinephrine in achieving anesthesia in maxillary teeth with irreversible pulpitis after buccal infiltration.
 
Article
A randomized, double-blind trial was conducted to compare the efficacy of 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine when used as a supplemental anesthetic. Forty-eight patients with irreversible pulpitis requiring supplemental buccal infiltration for endodontic therapy were given either 4% articaine with 1:100,000 epinephrine or 2% lidocaine with 1:100,000 epinephrine in a double-blind manner. A standard VAS pain scale was used to evaluate the patient's response to pain after a supplemental injection. The mean VAS score after supplemental anesthesia was 15.28 for 4% articaine with 1:100,000 epinephrine and 19.70 for 2% lidocaine with 1:00,000 epinephrine. The mean percentage change in VAS score was 70.5 and 62.2% for articaine and lidocaine, respectively. There was no statistically significant difference in the VAS pain score between 4% articaine with 1:00,000 epinephrine and 2% lidocaine with 1:00,000 epinephrine as a supplemental anesthetic.
 
Article
The purpose of this study was to measure the degree of anesthesia obtained with 4% prilocaine and 3% mepivacaine compared with 2% lidocaine (1:100,000 epinephrine) for inferior alveolar nerve block. Using a repeated measures design, 30 subjects randomly received an inferior alveolar injection using masked cartridges of each solution at three successive appointments. The first molar, first premolar, lateral incisor, and contralateral canine (control) were blindly tested with an Analytic Technology pulp tester at 3-min cycles for 50 min. Anesthetic success was defined as no subject response to the maximum output of the pulp tester (80 reading) within 16 min and maintenance of this reading for 50 min. Although subjects felt numb subjectively, anesthetic success as defined here occurred in 43 to 63% of the molars, in 53 to 67% of the premolars, and in 30 to 37% of the lateral incisors. No statistically significant differences in onset, success, or failure were found among the solutions. We conclude that the three preparations are equivalent for an inferior alveolar nerve block of 50-min duration.
 
Article
No study has compared 4% articaine with 1:100,000 epinephrine with 4% articaine with 1:200,000 epinephrine in a mandibular buccal infiltration of the first molar. The authors conducted a prospective, randomized, double-blind, crossover study comparing the degree of pulpal anesthesia obtained with 4% articaine with 1:100,000 epinephrine and 4% articaine with 1:200,000 epinephrine as a primary infiltration in the mandibular first molar. Eighty-six asymptomatic adult subjects randomly received a primary mandibular buccal first molar infiltration of a cartridge of 4% articaine with 1:100,000 epinephrine and a cartridge of 4% articaine with 1:200,000 epinephrine in 2 separate appointments. The authors used an electric pulp tester to test the first molar for anesthesia in 3-minute cycles for 60 minutes after the injections. The two 4% articaine formulations showed no statistically significant difference when comparing anesthetic success, onset of anesthesia, or incidence of pulpal anesthesia. The anesthetic efficacy of 4% articaine with 1:200,000 epinephrine is comparable to 4% articaine with 1:100,000 epinephrine in a primary mandibular buccal infiltration of the first molar.
 
Article
Bone cells can be exposed to high calcium in the course of endodontic treatment. To investigate the effects of high calcium on bone cell function, responses of a rat osteoblast cell line (UMR 106) were examined. Responsiveness of the cells to parathyroid hormone, prostaglandin F1 alpha, and ionomycin was assessed by measuring calcium transients elicited by these stimuli. Raising the medium calcium from 1.8 to 50 mM did not alter cell responsiveness. Pretreatment of the cells with the calcium pump inhibitor sodium vanadate prevented parathyroid hormone effects and slightly decreased prostaglandin F1 alpha effects in both normal and high calcium. The effect of ionomycin was prolonged in high calcium when vanadate was present. The results suggest that cells of the osteoblast phenotype can maintain calcium signaling in the presence of high extracellular calcium. These processes could play a role in the therapeutic effectiveness of high calcium in endodontic treatment.
 
Article
Intra-alveolar root fractures of posterior teeth are rare when compared with other dental injuries. This case report describes one vertical and two horizontal root fractures of teeth 3, 14, and 15. The teeth all tested normal to cold and electric pulp tests. The patient reported no history of accidental trauma, and no signs of scarring were found. These fractures were discovered during a routine full-mouth radiographic survey. All teeth were asymptomatic and in good function. During the 11 yr that followed, there was no dental treatment, except for routine periodontal maintenance. The patient had one abscess that occurred after 9 yr on tooth 3, which had to be extracted. The upper left molars are surprisingly still in function and asymptomatic. Either occlusal or lateral trauma may be the cause of these fractures. This would strongly suggest night guard appliances for patients who clench or grind. A psychological evaluation of the patient might reveal neurosis, anxiety, or stress situations affecting teeth.
 
Article
The action of chemicals such as calcium hydroxide (Ca(OH)2) and sodium hypochlorite (NaOCl) that are used as tissue solvents may be enhanced by prolonged contact. The objective of this study was to determine if sealing Ca(OH)2 and NaOCl into the canal space would improve debridement of both the main canal and areas inaccessible to files. Mesial root canals of 75 freshly extracted mandibular molars were step-back hand-instrumented. Another six molars were controls. Either Ca(OH)2, NaOCl, or no medication was sealed in the canals for 1 or 7 days. Canals were finally irrigated with H2O and prepared for histological evaluation. The cleanliness of main canals and inaccessible areas (isthmi and fins) at the apical, middle, and coronal thirds was examined, scored, and compared by nonparametric statistical analysis. Results showed no significant differences among different groups in either the 1-day or 7-day time intervals in either the main canal or inaccessible areas. Instrumentation combined with NaOCl irrigation alone accounted for the removal of tissue in the main canal. In conclusion, in this system, prolonged contact with Ca(OH)2 and NaOCl was similarly ineffective; neither contributed significantly to canal debridement.
 
Article
Cryopreservation preserves periodontal ligament cells but has a lower success rate with dental pulp cells (DPCs) because it causes inflammation. There are 2 well-known cryopreservation methods that reduce inflammation, slow freezing and rapid freezing, but the effects of the 2 methods on inflammation are not well-established. The purpose of this study was to compare the effects of the 2 different cryopreservation methods on CCL-13 induction from DPCs by using microarrays, real-time polymerase chain reaction (PCR), Western blotting, enzyme-linked immunosorbent assay, and confocal laser scanning microscopy (CLSM). In this study, the concentration of cryoprotectant was fixed, and the methods compared differed with respect to freezing speed. Initially we screened the DPCs of cryopreserved teeth with expression microarrays, and CCL-13 was identified as a differentially expressed gene involved in generalized inflammation. We then compared the expression of CCL-13 after exposing teeth to the 2 cryopreservation methods by using real-time PCR, Western blot, enzyme-linked immunosorbent assay, and CLSM. Expression of CCL-13 was up-regulated significantly only in the rapid freezing group, except in measurements made by real-time PCR. CLSM analysis also confirmed this up-regulation visually. Rapid freezing increased the expression of CCL-13 in DPCs compared with slow freezing. Understanding the inflammatory effect of cryopreservation should help to establish an optimal cryoprofile to minimize inflammation of DPCs and reduce the need for endodontic treatment.
 
Article
The purpose of this study was to investigate the efficacy of laser-activated irrigation (LAI) of 1320-nm neodymium-doped:yttrium-aluminum-garnet (Nd:YAG) laser on sealer penetration into dentinal tubules in the presence of 5.25% sodium hypochlorite (NaOCl) or 17% ethylenediaminetetraacetic acid (EDTA). The curved root canals (>20°) from 63 extracted human molars (negative control, n = 3) were prepared to size #30.06 with NaOCl irrigation. Teeth were divided into 4 groups (n = 15) as follows: group N, NaOCl irrigation without LAI; group E, EDTA irrigation without LAI; group NL, LAI with NaOCl; group EL, LAI with EDTA. In all groups, the laser fiber was inserted and withdrawn 4 times for 5 seconds each. Teeth were obturated with gutta-percha and fluorescent-labeled sealer. Transverse sections at 2 and 5 mm from root apex were examined with confocal laser scanning microscopy, and the percentage of sealer penetration into dentinal tubules was measured. Groups E, NL, and EL showed higher percentage of sealer penetration than group N (P < .05). With NaOCl as irrigant, LAI (group NL) resulted in significantly higher amount of sealer penetration than nonactivated group (group N) in both levels (P < .05). However, with EDTA, no significant differences in sealer penetration were observed between the laser-activated group (group EL) and its nonactivated counterpart (group E) in both levels (P > .05). The 1320-nm Nd:YAG laser activation with either NaOCl or EDTA was much better than NaOCl irrigation alone and as effective as EDTA final flush for sealer penetration into dentinal tubules. Additional use of laser with EDTA did not improve the quality of obturation in the curved canals.
 
Article
The purpose of this study was to investigate the efficacy of a 1440-nm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser on relieving pain in relation to the levels of inflammatory cytokine and neuropeptides in the root canal exudates of teeth with persistent symptomatic apical periodontitis. Forty teeth with persistent symptomatic apical periodontitis were randomly assigned to treatment groups: group L, intracanal irradiation of 1440-nm Nd:YAG laser with a 300-μm-diameter fiberoptic tip in addition to conventional root canal retreatment, and group C, conventional root canal re-treatment. The degrees of both spontaneous pain and the pain on percussion before and after treatment were recorded, and root canal exudate samples were collected to quantify the associated levels of substance P, calcitonin gene-related peptide (CGRP), and matrix metalloproteinase (MMP)-8 by immunoassay. All of the measured parameters were significantly reduced in group L (P < .05), whereas the level of pain on percussion, CGRP, and MMP-8 were significantly reduced in group C (P < .05). The 1440-nm Nd:YAG laser had significantly better effect on the relief of pain on percussion and the reduction of substance P, CGRP, and MMP-8 levels. The visual analog scale scores of perceived pain correlated with pain-related neuropeptides and inflammatory cytokine levels in root canal exudates. The 1440-nm Nd:YAG laser irradiation via fiberoptic tip to the teeth with persistent apical periodontitis provided promising consequences of pain and inflammation modulation.
 
Article
MicroRNAs are small noncoding RNAs that play crucial roles in regulating normal and pathologic functions. Bacterial lipopolysaccharide (LPS) is one of the key regulators of pulpal pathogenesis. This study investigated how LPS regulates microRNA expression and affects the phenotype of human dental pulp cells (DPCs). Primary DPCs were established and immortalized to achieve immortalized DPCs (I-DPCs). DPCs and I-DPCs were treated with LPS and examined to identify changes in microRNA expression, cell proliferation, and cell migration. Quantitative reverse-transcriptase polymerase chain reaction was used to detect changes in gene expression. Exogenous miR-146a expression was performed transfection with pre-mir-146a mimic. Knockdown of interleukin receptor-associated kinase (IRAK1) and tumor necrosis factor receptor-associated factor 6 (TRAF6) expression was performed by small interference oligonucleotide transfection. Western blot analysis was used to detect changes in the expression of the IRAK1 and TRAF6 proteins. The differentiation of DPCs was induced by osteogenic medium. I-DPCs had a higher level of human telomerase reverse transcriptase gene than the parental DPCs. Up-regulation of miR-146a expression and an increase in migration was induced by LPS treatment of DPCs and I-DPCs. Exogenous miR-146a expression increased the migration of DPCs and I-DPCs and down-regulated the expression of IRAK1 and TRAF6. Knockdown of IRAK1 and/or TRAF6 increased the migration of DPCs. The results suggested that LPS is able to increase the migration of DPCs by modulating the miR-146a-TRAF6/IRAK1 regulatory cascade.
 
Article
The systemic distribution of 14C-labeled formaldehyde which had been placed in the root canals of the canines of cats following pulpectomies was studied using liquid scintillation counting and wholebody autoradiographic technique. Radioactive 14C which had been placed in the canals was found in the plasma 30 min after the root canal procedure. The recovery of systemic 14C radioactivity increased with time. In addition, it seemed that approximately 3% of the dose placed in the teeth was excreted in the urine within 36 h. Whole-body autoradiograms indicated extensive concentration of 14C radioactivity in tissues other than those analyzed with the liquid scintillation technique.
 
Top-cited authors
Martin Trope
  • University of Pennsylvania
Shimon Friedman
  • University of Toronto
Frank Tay
  • Augusta University
Al Reader
  • The Ohio State University
John Baumgartner
  • Oregon Health and Science University