Root-End Filling Materials: Apical Microleakage and Marginal Adaptation
Cristina Braga Xavier, Ruben Weismann, Marília Gerhardt de Oliveira, Flávio Fernando Demarco, and Daniel Humberto Pozza
The purpose of this study was to evaluate the root-end sealing ability through dye leakage evaluation and the marginal adaptation through scanning electron microscopy (SEM) of some root-end filling materials. Thirty human uniradicular teeth were used. Teeth were divided into three groups: (1) retrofilled with MTA-Angelus, (2) with SuperEBA, and (3) with Vitremer. The root surfaces were isolated with nail polish and teeth were immersed in silver nitrate. Roots were sectioned transversally at each millimeter, in three sections and evaluated at a stereomicroscope to observe dye penetration. Using SEM the distance between the tested rootend filling materials and the surrounding dentin was measured at four points. The statistical analysis showed significant differences among the three materials in relation to the sealing ability (p < 0.05). Concerning marginal adaptation, MTA-Angelus presented the best results (p < 0.01). Absence of correlation between the two methodologies was clearly observed.
Effects on Smear Layer and Debris Removal with Varying Volumes of 17% REDTA after Rotary Instrumentation
Brent J. Crumpton, DMD, MS, Gary G. Goodell, DDS, MS, MA, Scott B. McClanahan, DDS, MS
The purpose of this study was to quantify the volume of 17% ethylene diamine tetra-acetic acid (EDTA) needed to efficiently remove the smear layer after rotary instrumentation, and to determine if additional irrigation has any effect on debris removal. Forty single canal teeth were instrumented with ProFile GT rotary instruments. Experimental groups were irrigated with 1, 3, or 10 ml of 17% EDTA for 1 min, followed by a final rinse with 3 ml of 5.25% sodium hypochlorite (NaOCl). Samples were scored for debris remaining and examined under SEM to determine quality of smear layer removal. There were no significant differences among groups when comparing either debris remaining or quality of smear layer removal. EDTA irrigation volume greater than 1 ml did not improve debris removal. Efficient removal of the smear layer was accomplished with a final rinse of 1 ml of 17% EDTA for 1 min, followed by 3 ml of 5.25% NaOCl.
The Effect of Disruption of Apical Constriction on Periapical Extrusion
Ali Cemal Tinaz, DDS, PhD, Tayfun Alacam, DDS, PhD, Ozgur Uzun, DDS, PhD, Murat Maden, DDS, PhD, and Guven Kayaoglu, DDS
The aim of this study was to compare the amount of apical extrusion during manual instrumentation and engine-driven rotary instrumentation in teeth with disrupted apical constriction. Fifty-two teeth were divided into two groups comprising 26 teeth each. Teeth in each group were further divided into two sub-groups, the apices of which were enlarged approximately to a diameter of 0.2 mm and 0.4 mm. One group was instrumented using standardized technique with K-files and the other with ProFile .04 Taper Series 29, while irrigating with sodium hypochlorite. Glass vial model was modified for collection of extruded debris and irrigant as well as to integrate an electronic apex locator to the experimental assemble. The statistical analysis using Student’s t test revealed no significant difference between instrumentation with K-files and ProFile .04 taper files (p > 0.05). There was a tendency with both techniques to extrude apically more material as the diameter of the apical patency increased.
Fracture Strength of Tooth Roots following Canal Preparation by Hand and Rotary Instrumentation
Patsandra P.S. Lam, Joseph E.A. Palamara, PhD, Harold H. Messer, MDSc, PhD
The study aimed to determine fracture loads in tooth roots after canal preparation using different techniques. Mesiobuccal roots of 39 extracted mandibular molars were used. Three groups each of 13 roots were prepared by stainless steel hand files (K-files), and two rotary nickel-titanium techniques (Lightspeed and Greater Taper files). After obturation, a vertical load was applied by means of a spreader inserted into the canal until fracture occurred. The mean fracture load was 10.2 ± 4.4 kg for K-files, 15.7 ± 9.1 kg for Lightspeed and 13.2 ± 6.1 kg for Greater Taper files, but differences were not statistically significant (p > 0.05). Most fracture lines were incomplete fractures on the buccal surface, followed by proximal and compound fractures. Greater apical enlargement (Lightspeed) or increased canal taper (Greater Taper files) did not increase fracture susceptibility of tooth roots.
The Effect of Thermocycling on a Colored Glass Ionomer Intracoronal Barrier
Scott M. Maloney, DDS, MS, Scott B. McClanahan, DDS, MS, Gary G. Goodell, DDS, MS, MA
The purpose of this study was to evaluate the effect of thermocycling on a colored glass ionomer intracoronal barrier used for the prevention of microleakage. Thirty single canal premolars were decoronated, standardized in length, instrumented, obturated, and randomly assigned to three groups. Group 1 received a 1 mm intracoronal barrier of Triage glass ionomer, group 2 received a 2 mmTriage barrier, and group 3 received no barrier. After incubation for sealer set, teeth were thermocycled. Microleakage was measured using the fluid transport model. Groups 1, 2, and 3 demonstrated 1.68 mm, 0.60 mm, and 23.24 mm of movement, respectively. Using ANOVA and Student-Neumann-Keuls, group 3 leaked significantly more (p < 0.05) than groups 1 and 2, with no difference between groups 1 and 2. A 1 or 2 mm intracoronal barrier of Triage significantly reduced coronal microleakage in thermocycled endodontically treated teeth.
The Effect of Antibiotics and Endodontic Antimicrobials on the Polymerase Chain Reaction
Ashraf F. Fouad DDS, MS, and Jody Barry, BA, MT(ASCP)
The effectiveness of endodontic antimicrobial treatment could be determined using sensitive molecular methods. The purpose of this study was to determine if antibiotics or endodontic reagents interfere with the ability of PCR to detect Enterococcus faecalis in vitro. Amoxicillin (25 mg/ml), clindamycin (15 mg/ml), tetracycline (25 mg/ml), doxycycline (10 mg/ml), calcium hydroxide, 1% buffered sodium hypochlorite (NaOCl1), 3% and 6% unbuffered NaOCl (NaOCl3 and NaOCl6), 2% chlorhexidine (CHX), 5% tincture iodine (TI), 2% iodine potassium iodide (IKI), chloroform (CF), 70% ethyl alcohol, 5% sodium thiosulphate, 5% citric acid or saline were added to 10⁵ or 10⁸ cells/ml E. faecalis ATCC 19433 for 1 h (1 wk for Ca(OH)₂). Using PCR, all specimens were positive except for NaOCl3 and NaOCl6. PCR with Ca(OH)₂ was positive with 10⁸ cells/ml but negative with 10⁵ cells/ml. The following reagents yielded negative culturing results: all antibiotics, Ca(OH) ₂, CHX, IKI, TI, NaOCl3, NaOCl6, and CF. BacLight nuclear staining revealed the presence of viable cells in all PCR positive, culture negative combinations, except for those with CF. Therefore, in the presence of threshold values of bacterial concentrations, all reagents tested except for NaOCl3 and NaOCl6 do not interfere with the detection of E. faecalis using PCR.
Ultrastructural Evaluation of the Apical Seal in Roots Filled with a Polycaprolactone-Based Root Canal Filling Material
Franklin R. Tay, BDSc (Hons), PhD, Robert J. Loushine, DDS, R. Norman Weller, DMD, W. Frank Kimbrough, DDS, David H. Pashley, DMD, PhD, Yiu-Fai Mak, BDS, MS, Ching-Ngor Shirley Lai, BDS, MS, Rakesh Raina, DDS, and M. Chad Williams, DMD
This in vitro study compared the ultrastructural quality of the apical seal achieved with Resilon/Epiphany and gutta-percha/AH Plus. Single-rooted extracted human teeth were prepared using a crown-down technique, debrided with NaOCl and EDTA, and obturated with either Resilon/Epiphany or gutta-percha/AH Plus. They were examined for gaps along canal walls using SEM, and for apical leakage using a transmission electron microscopy (TEM). SEM revealed both gap-free regions, and gap-containing regions in canals filled with both materials. TEM revealed the presence of silver deposits along the sealer-hybrid layer interface in Resilon/Epiphany, and between the sealer and gutta-percha in the controls. It is concluded that a complete hermetic apical seal cannot be achieved with either root filling materials.
Bending Fatigue Study of Nickel-Titanium Gates Glidden Drills
Neill H. Luebke, DDS, MS, William A. Brantley, PhD, Satish B. Alapati, BDS, MS, John C. Mitchell, PhD, Leonard L. Lausten, DDS, Glenn S. Daehn, PhD
ProFile nickel-titanium Gates Glidden drills were tested in bending fatigue to simulate clinical conditions. Ten samples each in sizes #1 through #6 were placed in a device that deflected the drill head 4 mm from the axis. The drill head was placed inside a ball bearing fixture, which allowed it to run free at 4000 rpm, and the total number of revolutions was recorded until failure. Fracture surfaces were examined with a scanning electron microscope to determine the initiation site and nature of the failure process. Mean ± SD for the number of revolutions to failure for the drill sizes were: #1: 1826.3 ± 542.5; #2: 5395.7 ± 2581.5; #3: 694.4 ± 516.8; #4: 261.0 ± 138.0; #5: 49.6 ± 14.9; #6: 195.9 ± 78.5. All drills failed in a ductile mode, and fracture initiation sites appeared to be coincident with machining grooves or other flaws, suggesting the need for improved manufacturing procedures.
Pilot Study of Correlation of Pulp Stones with Cardiovascular Disease
A.C. Edds, J.E. Walden, J.P. Scheetz, L.J. Goldsmith, C.L. Drisko, and P.D. Eleazer
We propose that calcification of dental pulp may have a similar pathogenesis as calcified atheromas and could lead to use of routine dental radiographs as a rapid screening method for early identification of potential cardiovascular disease (CVD). Fifty-five dental patients ages 20 to 55 were chosen because pulp stones in pulpally noninflamed teeth were not expected in this age group. They completed a questionnaire regarding their CVD status and that of their parents and siblings. Entry criteria included at least one asymptomatic, minimally restored, noncarious molar and no history of gout, renal disease, or renal lithiasis. Patients’ periapical radiographs of record were viewed to determine the presence of pulp stones. There was a significant relationship between pre-existing CVD and pulp stones (odds ratio of 4.4 with a 95% confidence interval of 1.1, 18.7), but no relationship was found for family history of CVD and pulp stones (odds ratio of 1.7 with a 95% confidence interval of 0.5, 5.5). Seventy-four percent (14/19) of patients with reported CVD had detectable pulp stones while only 39% (14/36) of patients without a history of CVD had pulp stones. This pilot study demonstrates that patients with CVD have an increased incidence of pulp stones in teeth with noninflamed pulps compared to patients with no history of CVD. No relationship was found between presence of pulp stones and family history of CVD. The findings suggest that dental radiographic determination of the presence or absence of pulp stones may have possibilities for use in CVD screening.
Comparison of the Efficiency and Effectiveness of Various Techniques for Removal of Fiber Posts
Matthew Lindemann, DDS, Peter Yaman DDS, MS, Joseph B. Dennison DDS, MS, and Alberto A. Herrero, DDS
A study was conducted to determine the efficiency and effectiveness of several techniques for fiber post removal. Four groups of 20 mandibular premolars were endodontically treated and obturated. Post spaces were prepared for the following post systems: ParaPost XH, ParaPost Fiber White, Luscent Anchors, and Aestheti- Plus. After cementation, 10 posts of each group were removed with their corresponding manufacturer’s removal kit and the other 10 removed with diamond burs and ultrasonics. Removal times were recorded and the teeth were sectioned vertically and microscopically analyzed for removal effectiveness based on a 0 to 5 point scale. Removal kits removed Luscent Anchors the fastest (mean = 3.9 min) and most effectively (mean = 2.6), while Aestheti-Plus posts were removed the slowest (mean = 7.3 min) and least effectively (mean = 3.4). Diamonds and ultrasonics required an average of 10 additional minutes for each fiber post system removal, yet removal effectiveness improved half a point. The results suggest recommended removal kits were significantly more efficient, while diamonds and ultrasonics were more effective. Removal kits could be enhanced with subsequent ultrasonic instrumentation to remove remaining fibers and cement.
An Evaluation of Root ZX and Elements Diagnostic Apex Locators
Marat Tselnik, DDS, J. Craig Baumgartner DDS, PhD, and J. Gordon Marshall, DMD
The purpose of this study was to compare the accuracy of the Root ZX and Elements Diagnostic electronic apex locators under clinical conditions. Thirty-six teeth planned for extraction were used. Each tooth was decoronated, coronally flared with Orifice Shapers, an irrigated with 2.6% sodium hypochlorite. Working lengths were measured with K-files using both electronic apex locators. The files were cemented at the last measured working length and the teeth were extracted. The apical 4-mm of each canal were exposed and photographed under 15× and 30× magnification. Images of each apex were projected and the distance from the file tip to the minor diameter was determined. The mean distances from the file tip to the minor diameter were 0.346 mm for the Elements Diagnostic and 0.410-mm for the Root ZX beyond the minor constriction.
In locating the minor constriction the Root ZX was accurate 75% of the time to ±0.5 mm, 83.3% ±0.75 mm, and 88.9% to ±1 mm. The Elements Diagnostic was accurate 75% of the time to _0.5 mm, 88.9% to ±0.75 mm, and 91.7% to ±1 mm. There was no statistically significant difference between the accuracy of the two electronic apex locators in locating the minor diameter (p < 0.05).
A Prospective, Randomized, Double-Blind Comparison of Bupivacaine and Lidocaine for Inferior Alveolar Nerve Blocks
Carmen Fernandez, DDS, MS, Al Reader, DDS, MS, Mike Beck, DDS, MA, and John Nusstein, DDS, MS
The purpose of this prospective, randomized, doubleblind study was to compare the degree of pulpal nesthesia obtained with 0.5% bupivacaine with 1:200,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine in inferior alveolar nerve blocks. Using a crossover design, inferior alveolar nerve blocks were randomly administered, in a double-blind manner, using 0.5% bupivacaine with 1:200,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine, at two separate appointments, to 39 subjects. A pulp tester was used to test for anesthesia until two consecutive readings of less than 80 were recorded on at least three of the five experimental teeth. Anesthesia was considered successful when two consecutive 80 readings were obtained within 15 min and the 80 reading was continuously sustained for 60 min. Anesthetic success was significantly improved for all teeth except the first molar with the lidocaine solution. Pulpal anesthesia averaged 4 hr for bupivacaine versus 2 hr and 24 min for lidocaine.
Exploiting Molecular Methods to Explore Endodontic Infections: Part 2—Redefining the Endodontic Microbiota
J. F. Siqueira, Jr, DDS MSc, PhD, I. N. Rôças, DDS, MSc, PhD
The second part of this review discusses the application of molecular methods in endodontic microbiology research for a comprehensive characterization of the microbiota associated with different types of endodontic infections. Despite their recent introduction in endodontic research, molecular methods have already given a significant contribution to the understanding of endodontic infections and the future holds the perspective of a still better refinement of the knowledge about these infections. Molecular methods have revealed a higher complexity of the endodontic microbiota than previously reported by cultivation approaches. In addition to detecting some cultivable species in increased prevalence, molecular methods have also expanded the list of putative endodontic pathogens by inclusion of some fastidious bacterial species or even uncultivated bacteria that have never been previously found in endodontic infections.