ABSTRACT Introduction: Medical imaging continues to play an increasing role in health care and is an integral part of medicine and dentistry. Recent technological advancements have led to the development of fully automated landmark identification (ALI) systems capable of tracing Cone-Beam Computed Tomography (CBCT). The purpose of this study was to evaluate the accuracy and reliability of an ALI system as a tool for automatic landmark location compared to human judges. Methods: One hundred subjects’ CBCT volumes from multiple imaging centers were traced by two human judges who were calibrated and had an ICC close to 1. Fifty-three landmarks were identified in the x, y, and z coordinate planes using Checkpoint Software (Stratovan Corporation, Davis, CA). The ground truth was created by calculating the mean values of the x, y, and z coordinates for each landmark across both judges’ landmark identification. To evaluate the accuracy of ALI, the mean absolute error at each coordinate and mean error distance (mm) between the human landmark identification (ground truth) and the ALI were determined, and a successful detection rate (SDR) was calculated. Results: Overall, the ALI system was as successful at landmarking as the human judges with the exception of a few landmarks. The mean error distance for all 53 landmarks was 4.04 mm ± 6.5. Forty-nine out of 53 landmarks were located within a mean error of 4mm when the average for the coordinates of human judges was considered as a ground truth. Conclusion: Across all three coordinate planes, 96% of the landmarks had a mean absolute error of less than 4mm when compared to the ground truth. The ALI was more precise than humans when identifying landmarks on the same image at different times. This study demonstrates the promise of ALI in aiding orthodontists with landmark identification on CBCTs in the future.

The objective of this study was to evaluate the biofilm removal efficacy of three root canal treatment systems: ProUltra® PiezoFlow™, traditional needle irrigation, and the GentleWave® system in an ex-vivo benchtop study. Twenty-four extracted maxillary and mandibular molars were selected. Teeth were all instrumented to a master apical file size #25 with 4% taper. Teeth were then randomly divided into four experimental groups and two control groups. The root canals were inoculated with a culture of Enterococcus faecalis and incubated for five weeks to form a biofilm. Each group was then treated with one of the different root canal treatment systems using 6% sodium hypochlorite (NaOCl) as per the respective manufacturer’s recommendation followed by a rinse with water. Following treatment, teeth were decoronated and roots were sectioned longitudinally. Three scanning electron microscope images were taken at the apical level per root half at 5000x magnification. Images were scored by four calibrated examiners blind to group membership using a four-point scoring system (<5% coverage, 5-33%, 34-66%, and >66%). Results were analyzed using mixed model ANOVA. All the experimental groups were significantly better than the positive control group in removing biofilm. Among the experimental groups, the GentleWave® 15/04 group was significantly better than the other groups. There was no significant difference between the GentleWave® and the ProUltra® PiezoFlow™. Traditional needle irrigation scored the worst in reducing E. faecalis biofilm. The GentleWave™ system was as effective at intracanal biofilm removal as the ProUltra® PiezoFlow™ and better than traditional needle irrigation using 6% NaOCl as an irrigant.

Numerous nickel titanium rotary file systems have been introduced in recent years. The recommended speed at which these files are to be operated varies widely between manufacturers. The purpose of this study was to test the number of rotations to fracture of NiTi rotary files when operated at different speeds and at different angles. Sixty size 25 Profile® nickel titanium rotary files were tested, thirty 0.04 and thirty 0.06 taper. Files were operated at speeds of 350 or 600 rpm and at angles of 25°, 28°, and 33.5°. The time to fracture was recorded and the numbers of rotations to fracture were calculated. The data was analyzed using a two-way ANOVA, and post hoc Tukey-Kramer multiple-comparison test with alpha = .001. The results show a significant difference in the number of rotations fracture according to taper and angle. Files of .06 taper fractured more readily than files of .04 taper as the speed increased, and the time to fracture decreased for both tapers as the angle increased. No significant difference was produced by the speed at which the files were operated. The number of rotations until fracture of NiTi rotary files is not related to the operational speed.

The purpose of this study was to examine the effect of immersion in sodium hypochlorite on nickel titanium rotary files and determine whether resistance to fracture was influenced by the immersion time. 70 ISO size 25 0.04 taper nickel titanium K3 and Profile rotary instruments were immersed in 5.25% sodium hypochlorite for 1, 5, 15, 30, 60, and 120 minutes (n=5 each). Resistance to fracture was tested by rotating files at a 30 degree angle at 350 rpm in a universal testing machine. Time to fracture was recorded and analyzed by a two-way ANOVA. Within both file types, there was a decreased time to fracture with increased immersion time in sodium hypochlorite. K3 files required an average of 327 rotations to fracture, while Profiles required 420 rotations to fracture. Profiles required significantly more rotations to failure than K3 files.

The purpose of this study was to quantitatively compare the fill density of MTA produced by hand condensation and hand condensation with indirect ultrasonic activation. Thirty acrylic block with 30 degree curved canals (group C) and 30 with straight canals (group S) were instrumented to a final apical size of 45 of 0.06 taper crown-down technique. After irrigating with water and drying with paper points, each block was weighed to the nearest 0.0001g with a digital electronic balance. In half of the specimens, chosen at random, the canal first filled with MTA using the hand condensation method (H) then weighed. The MTA was removed. The canal was rinsed, dried, and refilled using hand condensation with indirect ultrasonic activation (US). In the other half of the specimens, the procedure was carried out identically but in reverse order. The blocks were weighed again after cleaning the MTA from the canal as well as after refilling the canal using indirect ultrasonic condensation. Data comparing the weight of MTA between the two placement methods and the two canal configurations were analyzed by a two-way ANOVA. There was a statistically significant increase in weight of MTA produced by ultrasonic activation than by hand condensation in groups C (p<.0001) and S (p<.0001). However, there was no statistically significant difference when comparing the straight canal versus the 30-degree curved canal (p = .08). In group C, ultrasonic condensation resulted in a 10.07% increase in the weight of MTA over hand condensation alone. Similarly in group S, there was a 9.1% increase in the weight of MTA over hand condensation. In conclusion, hand condensation with indirect ultrasonic activation resulted in an MTA fill that was denser than that accomplished by hand condensation alone.

The purpose of this study was to compare the density of gutta percha following three different obturation techniques using two split-tooth models. One split-tooth model was constructed with a straight rooted maxillary incisor and the other with the curved palatal root of a maxillary molar. Each tooth was obturated using single cone, cold lateral, and warm vertical obturation techniques without sealer. Each obturation technique was performed 20 times for each of the root systems. The weights of the gutta percha were recorded for each root type and obturation technique by subtracting the post-fill weight from the pre-fill weight of the two split-tooth models. Results show that in the straight canal, the three obturation techniques are significantly different (p < 0.0001). The warm vertical technique had the largest weight of gutta percha, followed by the single cone, and lastly by the cold lateral condensation group. In the curved canal, the three fill types were also significantly different (p < 0.0001). The warm vertical and single cone obturation techniques were not significantly different from one another but were significantly greater in gutta percha weight than the cold lateral technique. In conclusion, within curved canals, warm vertical and single cone techniques were more dense than cold lateral condensation. In the straight canal, the warm vertical was more dense than the single cone which was more dense than the cold lateral technique.

The purpose of this study was to compare the number of rotations to failure of three different rotary file systems. ProFile, Sequence, and Liberator files in sizes 25 and 40 with 0.04 taper were divided into groups of five and rotated against a grooved metal block mounted to a Universal testing machine at 31 and 34 degrees. Each file was rotated at 300 rpm until fracture occurred. The number of rotations to fracture were calculated. Use of a three-way ANOVA and Tukey's HSD multiple comparison tests revealed significant differences for the angle of deflection, size, and type of file. An increased angle of deflection resulted in a decreased number of rotations to failure for all three file types. An increased size of file also resulted in a decreased number of rotations to failure in all the groups. Liberator and Sequence files required fewer rotations to failure than ProFiles in all groups tested except the size 25 files rotated at the less severe angle. ProFiles appear to be more resistant to flexural fracture than Liberator and Sequence files unless the files are of smaller size with a less severe curvature. Care should be taken to limit the number of uses when using larger size files, especially Liberator and Sequence files, around severe curvatures.

The purpose of this study was to test the predictive ability of specific questions in diagnosis of pulpal and periradicular disease in a dental school population. 210 patients were recruited to fill out a questionnaire, and undergo a clinical examination for pulpal and/or periradicular disease.The Questionnaire asked if the patient had in the last 6 months: 1. a toothache that kept them up at night 2. a toothache that required pain killers 3. facial swelling caused by a tooth 4. injury to any teeth 5. a broken tooth 6. a tooth darker in color than the surrounding teeth 7. a bump, pimple, or boil on the gums. 8. a toothache after eating or drinking something hot or cold 9. repeated sharp pain in the same area while chewing 10. A toothache or facial swelling that caused them to visit an emergency room.Examiners were blinded to the responses on the questionnaire and then, based on the clinical examination and testing, determined the presence or absence of endodontic disease. The data was analyzed using univariate logistic regression models.Results: The most predictive questions were #1 and #2 (p-value Conclusion: Patients with pain that wakes them at night or that requires analgesics were greater than 3 times more likely to have endodontic disease at the time of examination.

K3 ENDO, PRO TAPER, AND PRO FILE SYSTEMS: BREAKAGE AND DISTORTION IN SEVERELY CURVED ROOTS OF MOLARS.By Matthew T. Ankrum, D.D.S.A Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University.Virginia Commonwealth University, 2003Major Director: Gary R. Hartwell, D.D.S., M.S.Chairman and Professor, Department of EndodonticsIt was the aim of this study to investigate the incidence of file breakage and distortion when the Pro Taper, K3 Endo and ProFile systems were used to instrument canals in the severely curved roots of extracted molars.Forty-five roots of extracted mandibular and maxillary molars with curvatures between 40 and 75 degrees were chosen for use in this study. The roots in Group One were instrumented with the Pro File (PF) system and served as the control group. Roots in Group Two were instrumented with the Pro Taper (PT) system and those in Group Three were instrumented with the K3 Endo (K3) system. The three systems were used according to the manufacturers' instructions.The proportion of files distorted was 15.3% for the PF group, 2.4% for the PT group, and 8.3% for the K3 group. There was a statistically significant difference between the PF and PT groups (p = .0079). The percentage of broken files was 1.7% for the PF group, 6.0% for the PT group and 2.1% for the K3 group. No statistically significant differences were found between these three groups (p = .4243). The results of this study showed that these three rotary tapered systems were not significantly different with regard to breakage. There were significantly more distorted files in the PF group when compared to the PT group, with regard to distortion there was no significant difference between the PT and K3 and the PF and K3 groups.

Mature dendritic cells (DCs) in inflamed tissues may promote inflammation but the status of DCs in pulpitis is not known. We hypothesized that DC maturation would correlate with carious lesion depth and that CD4+ cells would be found in association with mature DCs. Pulps were collected from teeth exhibiting: (I) no caries (n=9), (II) shallow dentinal caries (n=5), and (III) deep caries (n=9). Pulpal tissues were cryo-sectioned and positive cells were examined with immunohistochemistry, Mature DCs (CD83+) were almost exclusively restricted to pulps from deep caries. Furthermore, CD209+ DCs in deep caries were elevated over other groups and CD209+ cells about doubled the CD83+ cells suggesting that immature DCs had accumulated and were available for terminal maturation. CD4+ cells were found associated with both mature DCs and macrophages in pulps from deep caries suggesting that T cells may be a source of pro-inflammatory cytokines at this inflamed site. This document was created in Microsoft Word 2000.