Rotary endodontic instruments have different cross sectional designs that may effect their resistance to torsional stress. The purpose of this study is to evaluate the static torsional properties of two nickel titanium files that have recently been introduced for use in endodontics and compare them to the same size Profile instruments. Ten new files of each brand and size were tested. The files tested were: RaCe 25 tip 0.02, 0.04, 0.06 taper, K3 and Profile 25 and 40 tip in 0.02, 0.04 and 0.06 taper. The diameter of each file was measured at 3mm from tip. The last three millimeters of the working area of the file was grasped with a non-rotating stainless steel chuck and the handle was held in freely rotating chuck. Torque was applied with the Instron Universal Tester in a counter-clockwise direction to simulate the direction of torque encountered clinically. The crosshead speed was set to produce 2 rotations per minute until fracture occurred. The maximum torque achieved and the rotations to fracture were recorded. A multi-way ANOVA of rotations revealed that RaCe 25-0.02 exhibited significantly less rotations to fracture than Profile and K3 of the same size (p<0.0001). RaCe 25 tip exhibited lower maximum torque in all tapers than corresponding K3 and Profile instruments. The mean diameter was significantly smaller for the RaCe files. In this study the RaCe file series exhibited lower values for maximum torque and rotations to fracture. These results should be taken into account while using these files clinically, however further testing is indicated.

The purpose of this study was to determine if the viscosity of MTA Angelus Fluid is lower than that of Pro Root MTA and MTA Angelus; and to compare the viscosity, leakage and particle size of these materials to determine whether a relationship exists between these properties. The viscosity of each material was measured and compared with the Student's t test. MTA Angelus Fluid's viscosity was significantly lower than the other two materials tested. Microleakage of root end fillings was assessed in a passive diffusion model. Leakage groups were compared with a one-way ANOVA (p < 0.05). No significant difference was found. Particle size and shape were evaluated with the SEM. MTA Angelus Fluid has a lower viscosity than the other materials tested. There was no significant difference in the sealing ability of the three materials tested and there was no apparent variation in each material's particle size or shape.

This study compared seven dental unit water line (DUWL) treatments and three in-office bacteria test kits. Sodium hypochlorite (NaOCl) 1:10 in tap water weekly; 3 drops of NaOCl in 1 liter of water; Dentapure® DP 40; ICX™ tablet; Sterilex® Ultra powder; Lines™; and Selective Micro® Dental-Clean. Traditional culture technique was compared to HPC Dental Sampler; Aquasafe™ Dental Unit Water Line Test Kit; and Bacteria in Water Test Kit. Eight dental units in the Virginia Commonwealth University Graduate Endodontic Clinic were randomly assigned treatment regimens. Samples were taken weekly initially and after flushing for 1 minute. In conclusion NaOCl hypochlorite 1:10 in tap water once weekly, Sterilex® Ultra, Lines™, and Selective Micro® Dental-Clean were effective at all sample times while ICX™, 3 drops of NaOCl, and Dentapure® DP 40 were only effective after 1 minute flushing. There was no significant difference between the in-office test kits and traditional culture.

This study determined if any of six endodontic solutions would have a softening effect on resorcinol-formalin paste in extracted teeth, and if there were any differences in the solvent action between these solutions. Forty-nine single-rooted extracted teeth were decoronated two mm coronal to the CEJ, and the roots sectioned apically to a standard length of 15 mm. Canals were prepared to a 12mm WL and a uniform size with a #7 Parapost drill. Teeth were then mounted in a cylinder ring with acrylic. The resorcinol-formalin mixture was placed into the canals and was allowed to set for 60 days in a humidor. The solutions tested were 0.9% sodium chloride, 5.25% sodium hypochlorite, chloroform, Endosolv R®, 3% hydrogen peroxide, and 70% isopropyl alcohol. Seven samples per solution were tested and seven samples using water served as controls. One drop of the solution was placed over the set mixture in the canal, and the depth of penetration of a 1.5 mm probe was measured at 2, 5, 10, and 20 min using a dial micrometer gauge. A repeated-measures ANOVA showed a difference in penetration between the solutions at 10 min (p=0.04) and at 20 min (p=0.0004). At 20 min, Endosolv R®, had significantly greater penetration than 5.25% sodium hypochlorite (p=0.0033) and chloroform (p=0.0018); however, it was not significantly better than the control (p=0.0812). Although Endosolv R®, had statistically superior probe penetration at 20 min, the softening effect could not be detected clinically at this time.

The use of Mineral Trioxide Aggregate (MTA) is gaining popularity among clinicians. Despite the many ideal qualities it possesses, it is often difficult to manipulate and often requires a second appointment for placement of a restoration to allow for setting. If the time to set of MTA can be accelerated to a single appointment time frame without significantly altering its properties, then MTA may gain even wider acceptance. The purpose of this study is to identify the percentage of a Portland Cement Accelerator (PCA), that when added to MTA, will decrease the time to set of MTA towards a single appointment time frame. Ten Teflon sample molds were prepared to hold 20 standardized chambers in each. Three sample molds were prepared with a 5.0% (by weight of MTA) accelerator, 3 with 10.0% accelerator and 3 with 15.0% accelerator mixed with MTA and water. Another sample mold contained a mixture of MTA and water only and acted as the control. Samples were tested using a dial indicator microgauge apparatus that measured the depth of needle penetration starting at 2 minutes and then every minute up to 15 minutes. Samples were also tested at 3, 4, 24, 48 and 72 hours. A mixed-model repeated measures ANOVA showed the four accelerator groups were significantly different and there was a significant time trend. The 5.0% accelerator group set significantly faster compared to the 15.0% and the control at 15 minutes or less (p<0.05). In conclusion, it appears that 5.0% PCA when added to MTA can accelerate the setting reaction.

The purpose of this study was to determine the changes in prescribing habits of active members of American Association of Endodontics (AAE) with regards to antibiotics in comparison to the findings reported by Yingling et al. in 1999. The invitations to take the online survey were sent via email to 2593 active members. A response rate of 37.75% was obtained. It was determined to be adequate for analysis and for comparison to the results obtained by Yingling et al. Comparisons between the percentages shown in this survey and the previous survey were tested using a z-test. An ANOVA model was used to determine the relationships between predictive factors and the number of prescriptions written. The change in distribution of respondents was notable with an increase in younger clinicians (25% in 1999 to 36% at present). They were more likely to be in private practice and much less in part-time academic and private practice setting. The number of patients being seen per week and the number of prescriptions written per week also decreased in comparison (p<0.001). For all the considered factors, it was also noted that board certified endodontists were prescribing less antibiotics per week. A positive correlation was noted for number of years in practice (p=0.0006), type of practice (p<0.001) and number of prescriptions written per week. Changes in choice of antibiotics were also noted. There was a decrease in use of Penicillin (61.48% to 43%), an increase in the use of Amoxicillin (27.5% to 37.6%), and an increase in use clindamycin (45.3% to 64%) for patients with no medical allergies. As for patients with medical allergies, there was a steep incline in the use of clindamycin (56.03% to 90.3%) as first choice to an increase in azithromycin (7.4% to 38%) as a second choice. An improved trend was noted with a significant decrease in use of antibiotics in managing most of the endodontic scenarios given. Antibiotic use in cases of irreversible pulpitis significantly dropped from 16.76% to 12% (p<0.05); in necrotic pulps with acute apical periodontitis with no swelling, a significant decline from 53.9% to 28.3% (p<0.001); significant decreases were also noted for necrotic pulp with chronic apical periodontitis with no/mild symptoms, 18.8% to 16.1% (p=0.029), and necrotic pulp with acute apical periodontitis with swelling and mod/severe symptoms, 99.2% to 92.4% (p<0.001). An exception was noted for necrotic pulp with chronic apical periodontitis with a sinus tract where there was a significant increase in antibiotic use from 11.9% to 29.1% (p<0.001). Many clinicians (19%) were still giving antibiotics due to soliciting of patients and referring general dentists in fear of losing referrals. A disturbing find is that 50% of the respondents were using antibiotics to manage post treatment flare-ups and pain, while 13% were using antibiotics for inter-appointment pain. As for prophylactic antibiotics, most clinicians were aware of the new AHA/ADA guidelines and were abiding by them. Most of the clinicians responding to survey were choosing the appropriate antibiotics and regimen (i.e. dosage, loading dose, and duration). Although there is an improvement in trends, it has to be noted that there is still an indiscriminate and overuse of antibiotics at large. There needs to be greater improvement in the use of antibiotics in endodontics, and a group effort as a specialty is needed in halting this alarming problem of antibiotic resistance globally.

The purpose of this study was to use existing Cone Beam Computer Tomography images to determine the vertical and horizontal location of the mental foramen in relation to the mandibular first and second premolars, as well as the distance in millimeters from the apex of each. The distance from the inferior border of the foramen to the inferior border of the mandible was also recorded. The average distance from the apices of the mandibular first and second premolars to the mental foramen was 7.43mm (SD= 1.97) and 5.30mm (SD=1.65) respectively. The foramen was located 11.44mm (SD=1.49) from the inferior border of the mandible. The foramen was in line with the apex of the mandibular second premolar 41% of the time. The mental foramen was further away from the inferior border of the mandible in males and older patients. Mental foramina seemed to be positioned more apically and distally in older patients.

The objective of this study was to compare the time to final set and compressive strength of the white mineral trioxide aggregate (MTA) formulation to the original grey MTA. To test compressive strength, each MTA formulation was placed into Teflon split molds for four hours at 37° Celsius (C) and 100% humidity. Compressive strength of both MTA formulations was measured at 24 hours (n=12) and 21 days (n=19) using an Instron Testing Machine. For determination of time to final set, each MTA formulation (n=6) was placed into a metal mold and maintained at 37° C and 100% humidity while setting. At five-minute time intervals, an indenter needle was lowered onto the surface of the MTA material and allowed to remain in place for five seconds before it was removed from the specimen surface. This process was repeated until the needle failed to make a complete circular indentation in the MTA specimen. Results of a two-way ANOVA indicate that white MTA had a significantly higher compressive strength (mean=32.7 MPa) than grey MTA (mean=25.2 MPa) at 24 hours and no statistically significant differences at 21 days (white mean=38.6 MPa and grey mean=38.0 MPa). Using one-way ANOVA, results indicate that grey MTA had a significantly longer time to final setting time (mean=296 min) compared to white MTA (mean=276 min). Based on this study, the results suggest that white MTA is an effective substitute for grey MTA.

The purpose of this study was to assess the changes in size of periapical lesions 3-12 months following root canal treatment using CBCT. Patients who had non-surgical root canal therapy (NSRCT) or non-surgical retreatment (ReTx) from July 30,2014 to August 19, 2015 with a periapical lesion of endodontic origin and received NSRCT or ReTx and had a pre-treatment or intra-treatment CBCT were invited to participate. Volumetric and linear measurements of periapical lesions on initial and post- treatment CBCT images were performed. A total of 20 patients with 23 treated teeth with 30 separate periapical radiolucent lesions returned for follow up 91-390 days after the initiation of endodontic treatment. Lesions showed an overall reduction in volume (p=0.0096), maximum coronal diameter (p=0.0117), maximum sagittal diameter (p=0.0071), and maximum axial diameter (p=0.0006). Lesions show a significant reduction in size 3-12 months following non-surgical endodontic treatment using CBCT.

Symptomatic apical periodontitis (SAP) is indicative of inflammation of the periodontal ligament. It may or may not be accompanied by radiographic changes and may occur with vital or necrotic pulpal diagnosis. Purpose of this study was to analyze clinical and radiographic presentations of SAP in a retrospective electronic dental chart and digital radiograph review utilizing the endodontic diagnostic template note of predoctoral dental school patients presenting with SAP. The aim was to determine prevalence of periapical radiolucencies (PARLs) in SAP, association of SAP to pulpal diagnosis, and define associated radiographic changes. Most prevalent pulpal diagnosis with SAP was symptomatic irreversible pulpitis (44%). A tooth presenting with SAP was more likely to have an intact lamina dura, but presented with a PARL 38% of the time. When a PARL was present the most common pulpal diagnosis was pulp necrosis however, 24.5% of teeth presented with a vital pulp diagnosis and lesions <2mm.