The Hidden Treasure in Apical Papilla: The Potential Role in Pulp/Dentin Regeneration and BioRoot Engineering
George T.-J. Huang, DDS, MSD, DSc, Wataru Sonoyama, DDS, PhD, Yi Liu, DDS, PhD, He Liu, DDS, PhD∥, Songlin Wang, DDS, PhD, Songtao Shi, DDS, PhD
Some clinical case reports have shown that immature permanent teeth with periradicular periodontitis or abscess can undergo apexogenesis after conservative endodontic treatment. A call for a paradigm shift and new protocol for the clinical management of these cases has been brought to attention. Concomitantly, a new population of mesenchymal stem cells residing in the apical papilla of permanent immature teeth recently has been discovered and was termed stem cells from the apical papilla (SCAP). These stem cells appear to be the source of odontoblasts that are responsible for the formation of root dentin. Conservation of these stem cells when treating immature teeth may allow continuous formation of the root to completion. This article reviews current findings on the isolation and characterization of these stem cells. The potential role of these stem cells in the following respects will be discussed: (1) their contribution in continued root maturation in endodontically treated immature teeth with periradicular periodontitis or abscess and (2) their potential utilization for pulp/dentin regeneration and bioroot engineering.
Evaluation of Pretreatment Analgesia and Endodontic Treatment for Postoperative Endodontic Pain
Sayeed Attar, DDS, MS, Walter R. Bowles, DDS, MS, BPharm†, Michael K. Baisden, DDS, James S. Hodges, PhD, Scott B. McClanahan, DDS, MS
This study compares single-dose ibuprofen pretreatment for postoperative endodontic pain. Thirty-nine emergent patients were randomly assigned to 3 groups: placebo, ibuprofen tablets, or ibuprofen liquigels. Patients recorded their pain levels before and at the end of treatment, then every 6 hours for 24 hours after administration of the medications and standard endodontic treatment. Pain evaluations by using 3 pain scales (visual analog scale [VAS], category, and Heft-Parker) were highly correlated, suggesting the rationale for only using one pain scale in pain studies. No significant differences in postoperative pain levels were found between either single-dose ibuprofen formulation or the placebo control group (P = .84). Patients treated with calcium hydroxide versus obturation did not differ in postoperative pain levels (P = .44). This study suggests that single-dose pretreatment analgesia alone in endodontic pain patients will not significantly reduce postoperative pain below the reduction in pain from endodontic treatment.
Anesthetic Efficacy of the Gow-Gates Injection and Maxillary Infiltration with Articaine and Lidocaine for Irreversible Pulpitis
Michael G. Sherman, DMD, Michael Flax, DDS, MS, Kenneth Namerow, DDS, Peter E. Murray, PhD
The aim of this randomized, double-blinded study was to compare the anesthetic efficacy of 4% articaine with 1:100,000 epinephrine (AE) with 2% lidocaine with 1:100,000 epinephrine (LE) for Gow-Gates blocks and maxillary infiltrations in patients experiencing irreversible pulpitis in mandibular and maxillary posterior teeth. Forty patients diagnosed with irreversible pulpitis of a posterior tooth randomly received either AE or LE by using a Gow-Gates injection or maxillary infiltration. Endodontic access was initiated after no response to Endo-ice 15 minutes after solution deposition. Success was defined as none to mild pain on a visual analogue scale after access. Chi-square and analysis of variance statistical tests were used to analyze the data. Successful endodontic treatment substantially reduced the assessment of pulpitis pain by patients (analysis of variance, P < .0001). Overall anesthetic success in both dental arches was 87.5%. Anesthetic success was not influenced by tooth arch (χ2, P > .7515) or gender (χ2, P > .1115). AE proved to be as effective but not superior to LE (P > .6002). These results demonstrated the similar anesthetic effectiveness of AE and LE when used during the endodontic treatment of teeth diagnosed with irreversible pulpitis.
A Prospective Clinical Study of Periradicular Surgery Using Mineral Trioxide Aggregate as a Root-end Filling
William Philip Saunders, BDS, PhD, FDS, RCSEdin, FDS, RCPS, FDS, RCS Eng, MRD, FHEA
A prospective outcome study of periradicular surgery using microsurgical techniques and root-end filling with mineral trioxide aggregate (MTA) was performed. Nonhealing endodontically treated teeth (n = 321) were included in the study. Surgery was completed under local anesthesia using a standardized clinical protocol. Patients were recalled periodically and examined for signs and symptoms of failure. Thirty-nine teeth were lost from recall. Of the 276 teeth examined, 163 showed complete healing radiographically with no other signs and symptoms; 82 teeth had no symptoms but incomplete or uncertain healing, and 31 teeth showed nonhealing (three had persistent pain despite evidence of complete radiologic healing and eight teeth did not heal for reasons unrelated to the surgical treatment). The overall success rate was 88.8%, including all teeth with no clinical symptoms. In this study, the use of MTA as a root-end filling, following microsurgical techniques, showed a high success rate.
Effect of Mineral Trioxide Aggregate on Dentin Bridge Formation and Expression of Dentin Sialoprotein and Heme Oxygenase-1 in Human Dental Pulp
Kyung-San Min, DDS, PhD, Hyo-Jin Park, DDS, MS, Sun-Kyung Lee, MS, Sang-Hyuk Park, DMD, PhD, Chan-Ui Hong, DDS, PhD, Hae-Won Kim, PhD, Hae-Hyoung Lee, DDS, PhD, Eun-Cheol Kim, DDS, PhD
This study was conducted to evaluate the pulpal response to direct capping with either mineral trioxide aggregate (MTA) or calcium hydroxide (CH) cement in humans, with a focus on dentin bridge formation and dentin sialoprotein (DSP) and heme oxygenase-1 (HO-1) expression. Direct pulp capping was performed in 20 cases of caries-free human third molars. The pulps were exposed and capped with either MTA or hard-setting CH. After 2 months, the teeth were extracted, and the specimens were prepared for histologic and immunohistochemical evaluations. Histologically, 100% of the MTA group and 60% of the CH group developed dentin bridges. The mean thickness of the dentin bridges observed in the MTA group was statistically greater than that of CH group. In addition, DSP and HO-1 were expressed in the odontoblast-like cells and pulp fibroblasts beneath the dentin bridge; furthermore, significantly greater immunostaining was observed in the MTA group than in the CH group. Collectively, these results indicate that MTA is superior to CH in terms of inducing the dentinogenic process in human pulp capping.
First Untoward Events and Reasons for Tooth Extraction after Nonsurgical Endodontic Treatment in Taiwan
Shih-Chung Chen, DDS, Ling-Huey Chueh, DDS, MS, Chuhsing Kate Hsiao, PhD, Hsin-Ping Wu, MS, Chun-Pin Chiang, DDS, DMSc
In this study, 857 teeth having undergone nonsurgical root canal treatment (NSRCT) in Taiwan in 2000 were evaluated during a 5-year follow-up period for first untoward events and reasons for tooth extractions. First untoward events occurred in 83 (9.7%) teeth during this follow-up period, and nonsurgical retreatment was performed for 20 (24.1%), 4 (4.8%) received apical surgery, and 59 (71.1%) were extracted. By the end of this 5-year follow-up period a total of 64 (7.5%) teeth had been extracted. There were 65 reasons for tooth extraction given by the 56 performing dentists who responded to the extraction reason questionnaires; 6 (10.7%) were attributed to endodontically related diseases, 15 (26.8%) to periodontal diseases, 26 (46.4%) to large decay or unrestorable tooth, and 18 (32.1%) to tooth fracture. The conclusion was that 7.5% of the NSRCT teeth were extracted by the end of the 5-year follow-up period, and only 10.7% of these teeth were extracted as a result of endodontically related diseases.
Prevalence and Management of Instrument Fracture in the Postgraduate Endodontic Program at the Dental School of Athens: A Five-year Retrospective Clinical Study
Giorgos N. Tzanetakis, DDS, MSc, Evangelos G. Kontakiotis, DDS, PhD, Dimitra V. Maurikou, DDS, MSc, Maria P. Marzelou, DDS, MSc
The aim of the present clinical research was to investigate the prevalence and management of instrument fracture during root canal preparation by postgraduate students (Department of Endodontics, Dental School of Athens) and to determine the percentage of referred cases with fractured instruments managed by the same students of the program. A retrospective study was conducted by reviewing the dental notes of 1367 patients (2180 endodontic cases, 4897 root canals) treated between October 2001 and June 2006 by endodontic postgraduate students at the Dental School of Athens. Type of tooth and canal, type and length of fractured segments, level of instrument fracture, and management that followed were recorded. The overall prevalence of instrument fracture during root canal preparation by postgraduate students was 1.83%. The prevalence of endodontic cases with fractured instruments referred to the endodontic postgraduates was 7.41%. The prevalence of stainless steel hand and rotary nickel-titanium instrument fracture by postgraduate students were 0.55% and 1.33%, respectively. The prevalence of instruments fractured in the apical third (52.5%) was significantly higher when compared with coronal (12.5%) and middle (27.5%) thirds of the canals. The retrieval or bypass of fractured instruments was most successful in the coronal (100%) and middle (45.4%) thirds when compared with the apical third (37.5%) of the canals. The fracture frequency was higher in retreatment cases in relation to the respective rate of initial therapies. On the basis of the results of this study, the prevalence of endodontic instrument fracture by the postgraduate students was relatively low. The prevalence of fracture of nickel-titanium rotary instruments was more frequent than that of hand instruments. Retrieval or bypass of the fractured instruments in the apical third was less successful.
Adiponectin Induces Dentin Sialophosphoprotein in Rat Dental Pulp Cells: An In Vitro Study
Yoshiyuki Yasuda, DDS, PhD, Toshiyuki Koike, DDS, PhD, Toru Kawamorita, DDS, Takashi Saito, DDS, PhD
Adiponectin is known to play an important role in the regulation of blood glucose levels through the mediation of adiponectin receptors 1 and 2 (AR1 and AR2, respectively). The purpose of this study was to investigate the role of adiponectin in dental pulp cells. The expressions of both AR1 and AR2 were observed in dental pulp by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting. Quantitative analysis of Alizarin Red S staining showed that 10 μg/mL of adiponectin significantly promoted mineralization by 1.6 times compared with control on day 12. However, no significant difference in mineralization was observed between control and 0.1 or 1 μg/mL adiponectin treatment. Moreover, real-time PCR results indicated that adiponectin (10 μg/mL) significantly increased the expression of dentin sialophosphoprotein (DSPP) by 2.3 and 1.8 times compared with control on days 8 and 12, respectively. These results indicated that adiponectin might promote mineralization by inducing DSPP expression in dental pulp cells.
Effect of 2-Hydroxyethyl Methacrylate on Human Pulp Cell Survival Pathways ERK and AKT
Gianrico Spagnuolo, DDS, PhD, Vincenzo D'Antò, DDS, Rosa Valletta, DDS, Caterina Strisciuglio, MD, Gottfried Schmalz, DMD, PhD, Helmut Schweikl, PhD, Sandro Rengo, DMD, DDS
Previous investigations have revealed that dental monomers could affect intracellular pathways leading to cell survival or cell death. Mitogen-activated protein kinase (MAPK) and protein kinase B (AKT) might mediate cell responses as well as cell survival and apoptosis. The purpose of this study was to evaluate the effects of 2-hydroxyethyl methacrylate (HEMA) on the ERK1/2 and AKT pathways in human primary pulp fibroblasts (HPCs). HPCs were treated with various concentrations of HEMA, after which viability and reactive oxygen species levels were determined by flow cytometry with Annexin V-PI staining and 2,7-dichlorofluorescine diacetate, respectively. Whole-cell extracts were immunoblotted with anti-P-Akt or anti–P-ERK1/2. Cell viability decreased in a dose-dependent manner after HEMA exposure, showing a significant decrease with 10 mmol/L HEMA (p < .05). HEMA treatment resulted in a 4-fold increase in reactive oxygen species formation (p < .05). A short HEMA exposure (30–90 minutes) increased ERK1/2 phosphorylation, whereas a decrease in the AKT phosphorylation was observed. Selective inhibitors of the ERK (PD98059) and AKT (LY294002) pathways amplified HPC cell damage after HEMA exposure. Our findings demonstrated that HEMA exposure modulates the ERK and AKT pathways in different manners, and that in turn, they function in parallel to mediate pro-survival signaling in pulp cells subjected to HEMA cytotoxicity.
RAGE mRNA Expression and Its Correlation with Nuclear Factor Kappa Beta mRNA Expression in Inflamed Human Periradicular Tissues
Michael Crabtree, DDS, Roberta Pileggi, DDS, MS, Indraneel Bhattacharyya, DMD, MS, Robert Caudle, PhD, Federico Perez, MS, Joseph Riley, PhD, Frank Vertucci, DMD, Joseph Katz, DMD
Advanced glycation end products (AGEs) have been found to play a role in inflammation and vascular complications. The receptor for AGE (RAGE) is expressed on many cells and is up-regulated during inflammation. To date, RAGE expression or its correlation with nuclear factor kappa beta (NF-κβ) expression has not been demonstrated in inflammatory periapical lesions. In this study, periapical tissue was obtained from 38 patients and processed for RAGE and NF-κβ expression by using reverse transcriptase polymerase chain reaction. Various patient variables were examined as predictors for these novel protein expressions. The results demonstrated a statistically significant positive correlation between the expression of RAGE and NF-κβ (P = .001). When comparing whites and African Americans, a statistically significant difference was noted, with the African American group exhibiting a higher expression of RAGE (analysis of variance, F= 12.746, P = .002). A positive linear correlation of their presence was demonstrated in inflamed periradicular tissues. This study outlines the possible use of these proteins as potential markers for periapical inflammation.
Glutathione Can Efficiently Prevent Direct Current–induced Cytotoxicity
Yuko Nakamura, DDS, PhD, Akiko Shimetani, DDS, PhD, Hiroko Fujii, PhD, Osamu Amano, DDS, PhD†, Hiroshi Sakagami, PhD, Keiso Takahashi, DDS, PhD
We have reported that direct current (DC) with antibacterial agents used in iontophoresis for root canal disinfection induced host cell necrotic cytotoxicity, and this DC-induced cytotoxicity may be because of generated free radicals and metal ions eluted from metal electrodes. Iontophoresis is still used in some cases, and thus it is necessary to consider how we may prevent DC-induced cytotoxicity of host cells of periapical lesions. Thus, we compared the protective effects of various antioxidants on the DC-induced cytotoxicity against host cells. N-acetyl-L-cysteine and glutathione (GSH) efficiently prevented DC-induced cytotoxicity against human polymorphnuclear cells (PMNs) (p < 0.01). The DC-induced cytotoxicity against PMNs was significantly enhanced by buthionine sulfoximine (p < 0.05), an inhibitor of GSH synthesis, and its effect was rescued by adding the exogenous GSH (p < 0.01). In addition, DC treatment reduced the intracellular GSH levels in a time-dependent manner (p < 0.05). Transmission electron microscopy showed that the DC induced the intense vacuolization and accumulation of cellular debris in autophagolysosomes, and these morphological changes were blocked by adding exogenous GSH. These results suggest that GSH, a thiol antioxidant, effectively prevents the DC-induced cytotoxicity.
Influence of Instrument Size on the Accuracy of Different Apex Locators: An In Vitro Study
Benjamín Briseño-Marroquín, PhD, MS, DDS, Santiago Frajlich, DDS, Fernando Goldberg, DDS, Brita Willershausen, PhD, DDS
The aim of this in vitro investigation was to determine the accuracy of 4 different electronic apex locators (EALs) with 3 different instrument sizes. For this study 146 roots were embedded in an agar solution. Electronic measurements were made to the physiologic foramen (apical constriction) with the Elements Apex Locator, Justy II, Raypex 5, and ProPex II and K-type files sizes 08, 10, and 15. Statistical significances were calculated with the sign test (P < .001). Exact measurements to the physiologic foramen were made with the Elements Apex Locator, 36.99%, 39.04%, and 44.93%; Justy II, 38.62%, 32.41%, and 43.41%; Raypex 5, 42.76%, 39.31%, and 39.06%; and ProPex II, 38.62%, 43.45%, and 40.63% of the time with instrument sizes 08, 10, and 15, respectively. No significant differences were found between the actual working length and EALs/instrument size. A nonsignificant higher number of unstable measurements were observed in all EALs with instrument size 15.
Soft Chelating Irrigation Protocol Optimizes Bonding Quality of Resilon/Epiphany Root Fillings
Gustavo De-Deus, MS, Fátima Namen, PhD, João Galan Jr, PhD, Matthias Zehnder, PhD
This study was designed to test the impact of either a strong (MTAD) or a soft (1-hydroxyethylidene-1, 1-bisphosphonate [HEPB]) chelating solution on the bond strength of Resilon/Epiphany root fillings. Both 17% EDTA and the omission of a chelator in the irrigation protocol were used as reference treatments. Forty extracted human upper lateral incisors were prepared using different irrigation protocols (n = 10): G1: NaOCl, G2: NaOCl + 17% EDTA, G3: NaOCl + BioPure MTAD (Dentsply/Tulsa, Tulsa, OK), and G4: NaOCl + 18% HEPB. The teeth were obturated and then prepared for micropush-out assessment using root slices of 1 mm thickness. Loading was performed on a universal testing machine at a speed of 0.5 mm/min. One-way analysis of variance and Tukey multiple comparisons were used to compare the results among the experimental groups. EDTA- and MTAD-treated samples revealed intermediate bond strength (0.3–3.6 MPa). The lowest bond strengths were achieved in NaOCl-treated samples (0.3–1.2 MPa, p < 0.05). The highest bond strength was reached in the HEBP-treated samples (3.1–6.1 MPa, p < 0.05). Under the present in vitro conditions, the soft chelating irrigation protocol (18% HEBP) optimized the bonding quality of Resilon/Epiphany (Resilon Research LLC, Madison, CT) root fillings.
Apical Extrusion of Root Canal Irrigants When Using Er:YAG and Er,Cr:YSGG Lasers with Optical Fibers: An In Vitro Dye Study
Roy George, BDS, MDS, Laurence J. Walsh, DDSc, PhD
Because of the potential for irritant reactions in the periapical region, irrigant solutions must be constrained within the root canal. We examined fluid extrusion beyond the apical constriction by pressure waves generated by pulsed middle infrared lasers using needles and Max-I-Probes (Dentsply) as controls. Both free-running pulsed Erbium: Yttrium Aluminum Garnet (Er:YAG) and Erbium, Chromium: Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) lasers with bare or conical fiber tips at distances of 5 or 10 mm from the apex displaced fluid past the apex. Larger apical openings showed greater extrusion of fluid. The volume of extruded fluid was similar to conventional 25-G needles, but fluid was distributed further from the apex. Because pulsed lasers create pressure waves in irrigant fluids within the root canal, the potential for extrusion of fluid from the apex should be considered when assessing intracanal laser treatments in endodontics.
Particle Size and Shape Analysis of MTA Finer Fractions Using Portland Cement
Takashi Komabayashi, DDS, PhD, Larz S.W. Spångberg, DDS, PhD
The aim of this study was to observe particle length, width, perimeter, and aspect ratio of mineral trioxide aggregate finer fractions using Portland cement. The High Power Field mode of the flow particle image analyzer was used for analysis. Images of particle samples were automatically collected by the analyzer along with analysis parameters. Mean, standard deviation, and the number of particles were calculated in each group. Parameters of length, width, and perimeter did not show a statistical significance when groups were compared. Examining the parameter of aspect ratio, there was evidence of a statistical significance seen (p<0.05). The cumulative percentage of particles that were between 0.5 and 3 µm in size was 88%. Fine particles may penetrate dentin tubules. The average aspect ratio was 0.744 (SD=0.155). It can be speculated that a dentin tubule occlusion pattern is dependent on the aspect ratio.
In Vitro Comparison of the Setting of Dry ProRoot MTA by Moisture Absorbed through the Root
Christopher Gene Budig, DDS, Paul Duncan Eleazer, DDS, MS
This study explored the potential of dry ProRoot mineral trioxide aggregate (MTA) (Dentsply Tulsa Dental, Tulsa, OK) powder to set solely by moisture absorbed through the root. Thirty-three single-rooted extracted teeth were decoronated and instrumented. The canal was packed with dry powder, and the coronal and apical 4 to 5 mm was sealed with nail varnish. Teeth were grouped and submerged in physiologic saline as follows: group A, 12 hours; group B, 36 hours; and group C, 72 hours. After submersion, the teeth were sectioned, and a 5-lb pound weight was placed on the Proroot MTA for 1 minute. The surface was evaluated for any evidence of penetration or fracture at 15× magnification. Nine of 10 samples were set at 72 hours versus 4 of 10 at 36 hours and 1 of 10 at 12 hours. Statistical analysis using a McNemar test with a significance of p < 0.05 found the number of roots in which dry MTA powder set at 72 hours versus 12 hours was statistically significantly different (p = 0.0133).
Influence of White versus Gray Mineral Trioxide Aggregate on Inflammatory Cells
Sepideh Vosoughhosseini, DMD, MSc, Mehrdad Lotfi, DMD, MSc, Shahriar Shahi, DMD, MSc, Hamid Baloo, DMD, MSc, Mehran Mesgariabbasi, VMD, Mohammad Ali Saghiri, MS, Vahid Zand, DMD, MSc, Saeed Rahimi, DMD, MSc, Bahram Ranjkesh, DMD
The aim of this investigation was to compare the quantity of inflammatory cells in response to white and gray mineral trioxide aggregate (MTA) in subcutaneous connective tissue of rats. Fifty Wistar rats were used in this study. Polyethylene tubes were filled with gray or white MTA and empty ones serving as the control group were implanted into subcutaneous tissue and harvested after 7-, 15-, 30-, 60-, and 90-day intervals. Sections of 5 μm were stained with hematoxylin and eosin and observed under a light microscope. Inflammatory reactions were categorized as 0, none (without inflammatory cells); 1, mild (inflammatory cells ≤25); 2, moderate (25-125 inflammatory cells); and 3, severe (more than 125 inflammatory cells). Statistical analysis was performed with the Kruskal-Wallis test. Both kinds of MTA provoked severe inflammatory reaction after 7 days, which significantly differed from control group (p < 0.05). However, there were no significant differences at any time period beyond 15 days (p > 0.05).
In Vitro Comparison of Coronal Microleakage between Resilon Alone and Gutta-Percha with a Glass-ionomer Intraorifice Barrier Using a Fluid Filtration Model
Ryan M. Jack, DDS, MS, Gary G. Goodell, DDS, MS, MA
The prevention and control of coronal microleakage is critical for successful endodontic outcomes. The purpose of this study was to compare coronal microleakage between Resilon alone and gutta-percha with a glass ionomer intraorifice barrier using a fluid filtration model. Thirty-four extracted human teeth were decoronated, prepared to a standardized length of 16 mm, and instrumented to a .06 taper ISO size 40. After removal of controls, the remaining roots were randomly divided into two equal groups of 15 and obturated with either Resilon alone or gutta-percha with a 2-mm glass-ionomer intraorifice barrier. After set of the sealers, the teeth were evaluated for microleakage using a fluid filtration model. A Student t test found significantly less leakage for the gutta-percha/glass-ionomer intraorifice barrier group than the Resilon alone group (p = 0.008).
Effect of 980-Nanometer Diode Laser on Root Canal Permeability after Dentin Treatment with Different Chemical Solutions
Melissa Andréia Marchesan, DDS, PhD, Aldo Brugnera-Junior, DDS, PhD, José Estevam Ozorio, DDS, MSc, Jesus Djalma Pécora, DDS, PhD, Manoel D. Sousa-Neto, DDS, PhD
This study evaluated the effect of 980-nm diode laser at different parameters on root canal dentin permeability associated with different irrigants. Seventy-five canines were sectioned at 15 mm from the apex, prepared mechanically up to #40 .02 instrument, and irrigated with 2 mL distilled water. Final irrigation (10 mL) was used as follows: (1) distilled water; (2) 1% NaOCl; (3) 17% ethylenediaminetetraacetic acid + a cationic surfactant cetyltrimethylammonium bromide (EDTAC). Laser was applied at 1.5 or 3.0 W as either continuous wave or pulsed wave (100 Hz). The teeth were then processed histochemically, the percentage of copper ion penetration into the dentin of the canal walls was counted, and the data were analyzed statistically with the Tukey-Kramer test (α < .01). When laser was associated with water, an increase in permeability was found, whereas permeability decreased when associated with EDTAC. Dentin permeability after laser irradiation was directly dependent on the solution used for final irrigation.
Comparative Assessment of ActiV GP/Glass Ionomer Sealer, Resilon/Epiphany, and Gutta-Percha/AH Plus Obturation: A Bacterial Leakage Study
Joel N. Fransen, DMD, Jianing He, DMD, PhD, Gerald N. Glickman, DDS, MS, Alejandro Rios, DDS, Jay D. Shulman, DMD, MA, MSPH, Allen Honeyman, PhD
The objective of this study was to compare the sealing ability of ActiV GP/glass ionomer (GI) sealer (Brasseler USA, Savannah, GA), Resilon/Epiphany (Pentron Clinical Technologies, Wallingford, CT), and gutta-percha (GP)/AH Plus (Dentsply Maillefer, Tulsa, OK). Seventy-three human single-rooted teeth were randomly divided into three test groups (20 canals each) and two control groups (5 positive and 8 negative). Using Enterococcus faecalis, a split-chamber bacterial leakage model was developed to evaluate the sealing ability of the three obturation systems. Samples were monitored every 24 hours for 65 days. Thirteen teeth leaked in both the Resilon/Epiphany and GP/AH Plus groups, whereas 17 teeth leaked in the ActiV GP/GI group at the end of the observation period. There were no statistically significant differences in the resistance to leakage between the three obturation systems (p > 0.05).
Photodynamic Treatment of Endodontic Polymicrobial Infection In Vitro
Jacob Lee Fimple, DDS, Carla Raquel Fontana, DDS, PhD, Federico Foschi, DDS, PhD, Karriann Ruggiero, BS, Xiaoqing Song, MD, MS, Tom C. Pagonis, DDS, MS, Anne C.R. Tanner, BDS, PhD, Ralph Kent, ScD, Apostolos G. Doukas, PhD, Philip P. Stashenko, DMD, PhD, Nikolaos S. Soukos, DDS, PhD
We investigated the photodynamic effects of methylene blue on multispecies root canal biofilms comprising Actinomyces israelii, Fusobacterium nucleatum subspecies nucleatum, Porphyromonas gingivalis, and Prevotella intermedia in experimentally infected root canals of extracted human teeth in vitro. The 4 test microorganisms were detected in root canals by using DNA probes. Scanning electron microscopy showed the presence of biofilms in root canals before therapy. Root canal systems were incubated with methylene blue (25 μg/mL) for 10 minutes followed by exposure to red light at 665 nm with an energy fluence of 30 J/cm2. Light was delivered from a diode laser via a 250-μm diameter polymethyl methacrylate optical fiber that uniformly distributed light over 360 degrees. Photodynamic therapy (PDT) achieved up to 80% reduction of colony-forming unit counts. We concluded that PDT can be an effective adjunct to standard endodontic antimicrobial treatment when the PDT parameters are optimized.
Antibacterial Properties of Four Endodontic Sealers
Iris Slutzky-Goldberg, DMD, Hagay Slutzky, DMD, Michael Solomonov, DMD, Joshua Moshonov, DMD⁎, Ervin I. Weiss, DMD, Shlomo Matalon, DMD
The purpose of this study was to evaluate the antimicrobial effects of root canal sealers. The direct contact test (DCT) was used to assess the antibacterial properties of AH plus, Apexit Plus, Epiphany SE, and RoekoSeal when in contact with Enterococcus faecalis. The materials were examined immediately after setting and 1, 2, 7, and 14 days after aging in phosphate-buffered-saline. Statistical analysis with two-way analysis of variance, one-way analysis of variance, and Tukey multiple comparison was applied to the data. Apexit Plus had a short-term antibacterial effect of 1 day on E. faecalis, whereas Epiphany SE enhanced bacterial growth for at least 7 days. AH plus and RoekoSeal were ineffective.
Diagnosis of Vertical Root Fractures with Optical Coherence Tomography
Hagay Shemesh, DMD⁎, Gijs van Soest, PhD, Min-Kai Wu, PhD, Paul R. Wesselink, PhD
The purpose of this experiment was to evaluate the ability of optical coherence tomography (OCT) to image vertical root fractures (VRFs). Twenty-five mandibular premolars were prepared to size 50. Five teeth served as controls. Group 1 (n = 10) was treated with ethylenediaminetetraacetic acid and ultrasonic irrigation, whereas group 2 (n = 10) received no further treatments. Teeth from groups 1 and 2 were fractured, and the presence of a fracture line was demonstrated microscopically. Control group teeth were not subjected to any force. Teeth were pooled and scanned with an OCT fiber. The resulting video files were blindly interpreted by 2 observers .No fractures were detected in the control teeth. The overall sensitivity for detection of VRFs with OCT was 93% for group 1 and 84% group 2, whereas the specificity was 95% for group 1 and 96% for group 2. OCT is a promising nondestructive imaging method for the diagnosis of VRFs.
Comparison of Forces Generated During Root Canal Shaping and Residual Stresses of Three Nickel–Titanium Rotary Files by Using a Three-Dimensional Finite-element Analysis
Hyeon-Cheol Kim, DDS, MS, PhD, Gary Shun-Pan Cheung, MDS, MSc, PhD, Chan-Joo Lee, Byung-Min Kim, PhD, Jeong-Kil Park, DDS, MS, PhD⁎, Soon-Il Kang, DDS, MS
The study was aimed to compare the stress distribution during simulated root canal shaping and to estimate the residual stress thereafter for some nickel-titanium rotary instruments. Three brands of instruments (ProFile, ProTaper, and ProTaper Universal; Dentsply Maillefer) were scanned with micro–computed tomography to produce a real-size, 3-dimensional model for each. The stresses on the instrument during simulated shaping of a root canal were analyzed numerically by using a 3-dimensional finite-element package, taking into account the nonlinear mechanical behavior of the nickel-titanium material. From the simulation, the original ProTaper design showed the greatest pull in the apical direction and the highest reaction torque from the root canal wall, whereas ProFile showed the least. In ProTaper, stresses were concentrated at the cutting edge, and the residual stress reached a level close to the critical stress for phase transformation of the material. The residual stress was highest in ProTaper followed by ProTaper Universal and ProFile.
The Physical and Cytological Properties of White MTA Mixed with Na2HPO4 as an Accelerant
Shinn Jyn Ding, PhD, Chia Tze Kao, DDS, MMD, PhD, Ming You Shie, DDS, MD, Chi Hung Jr, DDS, MD, Tsui Hsein Huang, DDS, MD, PhD
The purpose of the present study was to evaluate the physicochemical and cytologic properties of mineral trioxide aggregate (MTA) mixed with distilled water and Na2HPO4 buffer solution. The MTA setting time and pH value were evaluated. An MTA micrograph on scanning electron microscopy (SEM) was observed. Mouse fibroblasts (an L929 cell line) were used to test the toxicity of MTA after the first and seventh day of treatment by mitochondiral colorimetric assay. The results show the Na2HPO4 buffer group reduced the MTA setting time, and the pH value as in the distilled water group is similar with the Na2HPO4 buffer group. The mixed MTA's XRD produced similar peaks of the distilled water and Na2HPO4 buffer solution groups. The L929 cell survival rate of distilled water and H2PO4 buffer solution groups did not exhibit any significant difference (p < 0.05). There are differences in SEM observations both of the MTA surface and of the cells in culture on the surface of the MTA with Na2HPO4 versus distilled water. The results suggest that 15% Na2HPO4 buffer can be successfully used as an accelerator of MTA.
Post Space Debridement in Oval-shaped Canals: The Use of a New Ultrasonic Tip with Oval Section
Ivanovic Coniglio, DDS, MSc, Carlos Augusto Carvalho, DDS, Elisa Magni, DDS, MSc, Amerigo Cantoro, DDS, MSc, Marco Ferrari, MD, DDS, PhD
This study evaluates the effect on post space debridement in oval-shaped canals of an experimental ultrasonic tip with oval section (Satelec) compared with a circular ultrasonic tip (KaVo). Thirty teeth with an oval-shaped canal were endodontically treated and obturated and then randomly divided into 3 groups (n = 10) according to the procedure used for post space debridement: Satelec tip, Largo #2 drill + KaVo file, and Largo #2 drill + water. Debris and dentin tubules were evaluated by assigning scores to scanning electron microscope post spaces images; lower scores corresponded to fewer debris and higher number of open tubules. The Satelec group showed significantly lower debris and open tubules scores than KaVo group (p < .05) and control group (p < .05), which differed significantly between each other (p < .05). Also the debris and open tubules scores in different post space regions differed significantly among the experimental groups (p < .001). The oval ultrasonic tip resulted in a better post space debridement than a circular ultrasonic tip in oval-shaped canals.
Endodontic Treatment of a Maxillary Canine with Type 3 Dens Invaginatus and Large Periradicular Lesion: A Case Report
Damian Lichota, DDS, PhD, Mariusz Lipski, DDS, PhD, Krzysztof Woźniak, DDS, PhD, Jadwiga Buczkowska-Radlińska, DDS, PhD
Dens invaginatus type 3 is an anomaly characterized by an infolding of enamel and dentin that can extend up to the root apex and might present difficulties with respect to its diagnosis and treatment because of canal morphology. This article describes an unusual case of the maxillary canine having a type 3 dens invaginatus, necrotic pulp, and an associated large periradicular lesion treated by conventional root canal therapy. After gaining access to the pulp chamber, the primary canal and the invagination were localized, negotiated, enlarged, and filled with calcium hydroxide. Three weeks later the canal and the invagination were obturated with gutta-percha and restored. At 24-month recall satisfactory bone healing had occurred.