Speed of Injection Influences Efficacy of Inferior Alveolar Nerve Blocks: A Double-Blind Randomized Controlled Trial in Volunteers
Mohammad Dib Kanaa, MPhil, DDS, John Gerard Meechan, PhD, BDS, Ian Porter Corbett, PhD, BDS, John Martin Whitworth, PhD, BChD
This randomized double-blind crossover trial investigated the efficacy and discomfort associated with slow (60 seconds) and rapid (15 seconds) inferior alveolar nerve blocks (IANB) using 2.0 ml of 2% lidocaine with 1:80,000 epinephrine in securing mandibular first molar, premolar and lateral incisor pulp anesthesia in 38 healthy adult volunteers. Episodes of maximal stimulation (80 μA) without sensation on electronic pulp testing were recorded. Injection discomfort was self-recorded by volunteers on 100 mm visual analogue scales. Data were analyzed by McNemar, Friedman, Wilcoxon Signed Ranks, and paired t tests. Slow IANB produced more episodes of no response to maximal pulp stimulation than rapid IANB in molars (220 episodes versus 159, p < 0.001), premolars (253 episodes versus 216, p = 0.003) and lateral incisors (119 episodes versus 99, p = 0.049). Slow IANB was more comfortable than rapid IANB (p = 0.021).
Demographic Characteristics of Endodontic Practice Sites in the United States
Eric S. Solomon, DDS, MA, Gerald N. Glickman, DDS, MS, MBA
Few studies have addressed the demographic characteristics of dental practice sites including endodontic practice sites. This study investigated the demographic characteristics of endodontic practice sites in the United States. Demographic data and endodontic practices were organized by zip codes and analyzed using discriminant analysis. The demographic characteristics associated with zip codes that contained an endodontic practice were determined versus the characteristics of zip codes that did not contain an endodontic practice. The resulting model correctly classified 93.7% of the 30,171 zip code areas based upon the presence or absence of an endodontic practice. The variables most closely associated with a zip code containing an endodontic practice included: number of dental practices (nonendodontic), population size, percent of adult population with a college degree, size of employed population, projected population growth (2005 to 2010), percent of population over 64 years old, and median housing value.
Survival Rate of Endodontically Treated Teeth With Posts After Prosthetic Restoration
Pia K. Wegner, Sandra Freitag, PhD, Matthias Kern, DMD, PhD
The purpose of this retrospective clinical study was to evaluate the survival rate of teeth that were endodontically treated and restored with endodontic posts and prosthodontic restorations. A total of 864 teeth in 360 patients were included in the study. Dental records and radiographs of the patients were evaluated and four parameters were documented. The parameters were type of post, type of prosthodontic restoration, observation time, and, in cases of failure, failure mode. Statistical survival analyses were performed according to Kaplan-Meier. The mean observation time was 22.5 ± 14.9 months. The calculated survival rates of the abutments were statistically significant different for fixed partial dentures (FPDs) and for removable partial dentures (RPDs) with survival rates of 92.7% and 51.0% after 60 months, respectively. Most of the presumed factors influencing the survival rate of endodontically treated abutment teeth only affected the outcome in the RPD group. Teeth restored with post and cores present a high risk for failure when used as abutments for conical-double-crown-retained RPDs.
Complicated Root Canal Morphology of Mandibular First Premolar in a Chinese Population Using the Cross Section Method
Tzu-Yi Lu, DDS, Shue-Fen Yang, DDS, MS, Sheng-Fang Pai, DDS
The purpose of this study was to assess the canal anatomy and morphology of mandibular first premolars in a Chinese population. Eighty-two extracted mandibular first premolars with intact roots were collected and stored in a glutaraldehyde solution. The teeth were embedded in clear resin and the root length was measured. The roots were resected perpendicular to the long axis at 3, 6, 9, and 12 mm from the apex. The resected root surfaces were polished, rinsed, dried, and stained with methylene blue. Digital photographs of the cross-sectional root surfaces were made at 24X. The incidence of multiple canals and varied morphology was determined by two independent examiners. The results indicated that 54% of the mandibular first premolars demonstrated a single canal. Twenty-two percent contained two canals and 18% percent had C-shaped configuration. The C-shaped root canal occurred predominantly in the 3 and 6 mm sections with one or two canals coronally. A unique finding was the circumferential canal (apical delta), which was characterized by a single canal splitting into 3 or 4 canals. The incidence of circumferential canal was 6% and occurred only in the apical 3 mm cross-sections. Identification of this unique apical canal configuration and the high incidence of multiple canals in mandibular first premolars may explain endodontic treatment failure in this tooth group.
Molecular Analysis of Filifactor alocis, Tannerella forsythia, and Treponema denticola Associated With Primary Endodontic Infections and Failed Endodontic Treatment
Brenda P.F.A. Gomes, DDS, MS, PhD, Rogério C. Jacinto, DDS, MS, Ericka T. Pinheiro, DDS, MS, PhD, Ezilmara L.R. Sousa, DDS, MS, PhD, Alexandre A. Zaia, DDS, MS, PhD, Caio C.R. Ferraz, DDS, MS, PhD, Francisco J. Souza-Filho, DDS, MS, PhD
The aim of this study was to investigate the presence of strict anaerobes such as Filifactor alocis, Tannerella forsythia, and Treponema denticola in primary and secondary root-infected canals with periapical lesions by molecular analysis and the association of these species with specific endodontic signs and symptoms. Microbial samples were taken from 100 root canals, 50 with necrotic pulp tissues (NPT, primary infection), and 50 with failed endodontic treatment (FET, secondary infection). DNA was extracted from the samples, which were analyzed for the presence of three endodontic pathogens using species-specific primers and PCR. F. alocis were isolated from 23 canals with NPT and 12 canals with FET; T. forsythia from 12 canals with NPT and three canals with FET; T. denticola from 19 canals with NPT and 12 canals with TEP. Suggested associations were found between primary infection and the presence of F. alocis and T. forsythia (both p < 0.05). In particular, associations were found between: pain and F. alocis; swelling and F. alocis; tenderness to percussion and T. forsythia; mobility and T. forsythia and T. denticola; wet canals and F. alocis, T. forsythia, and T. denticola; purulent exsudate and F. alocis, T. forsythia and T. denticola; abscess and F. alocis, T. forsythia, and T. denticola (all p < 0.05). The findings of this study indicated that F. alocis, T. forsythia, and T. denticola seem to be associated with endodontic signs and symptoms. Additionally, F. alocis and T. forsythia were detected more frequently in teeth with necrotic pulp than in teeth with failing endodontic treatment.
Quantitative Three-Dimensional Analysis of Root Canal Curvature in Maxillary First Molars Using Micro-Computed Tomography
Jong-Ki Lee, DDS, MSD, Byung-Hyun Ha, PhD, Jeong-Ho Choi, DDS, PhD, Seok-Mo Heo, DDS, Hiran Perinpanayagam, DDS, PhD
In endodontic therapy, access and instrumentation are strongly affected by root canal curvature. However, the few studies that have actually measured curvature are mostly from two-dimensional radiographs. The purpose of this study was to measure the three-dimensional (3D) canal curvature in maxillary first molars using micro-computed tomography (microCT) and mathematical modeling. Extracted maxillary first molars (46) were scanned by microCT (502 image slices/tooth, 1024X1024 pixels, voxel size of 19.5 × 19.5 × 39.0 μm) and their canals reconstructed by 3D modeling software. The intersection of major and minor axes in the canal space of each image slice were connected to create an imaginary central axis for each canal. The radius of curvature of the tangential circle was measured and inverted as a measure of curvature using custom-made mathematical modeling software. Root canal curvature was greatest in the apical third and least in the middle third for all canals. The greatest curvatures were in the mesiobuccal (MB) canal (0.76 ± 0.48 mm−1) with abrupt curves, and the least curvatures were in the palatal (P) canal (0.38 ± 0.34 mm−1) with a gradual curve. This study has measured the 3D curvature of root canals in maxillary first molars and reinforced the value of microCT with mathematical modeling.
Coaggregation Interactions Between Oral and Endodontic Enterococcus faecalis and Bacterial Species Isolated From Persistent Apical Periodontitis
Erika M. Johnson, DDS, Susan E. Flannagan, MA, Christine M. Sedgley, PhD
Interactions between Enterococcus faecalis and other species found in root canal infections might be important for the development and persistence of periapical disease. The aim of this study was to investigate the coaggregation interactions between E. faecalis clinical isolates and species previously shown to survive and induce apical periodontitis in monkeys: Peptostreptococcus anaerobius, Prevotella oralis, Fusobacterium nucleatum, and Streptococcus anginosus. Intergeneric coaggregation assays were conducted in duplicate with observations scored immediately at 0 h, 1 h and 24 h after mixing of combinations of strains. All E. faecalis strains (n = 53) coaggregated with F. nucleatum; E. faecalis did not coaggregate with P. anaerobius or S. anginosus. One strain, E. faecalis E1, coaggregated with P. oralis, with aggregates visible at 1 h. Coaggregation interactions between E. faecalis and F. nucleatum observed in this study suggest a potential role for this combination in endodontic infections.
TLR4 Mediates LPS-Induced VEGF Expression in Odontoblasts
Tatiana M. Botero, DDS, Charles E. Shelburne, PhD, G. Rex Holland, DDS, MS, PhD, Carl T. Hanks, DDS, MS, PhD, Jacques E. Nör, DDS, MS, PhD
Lipopolysaccharide (LPS) from gram-negative bacteria cell walls such as Prevotella intermedia and Escherichia coli induce vascular endothelial growth factor (VEGF) expression in odontoblasts, but not in undifferentiated dental pulp cells. CD14 and TLR4 are responsible for LPS signaling in macrophages, but their expression levels and function in dental pulp cells are unknown. We showed here that murine odontoblast-like cells (MDPC-23) express CD14 and TLR4 by immunohistochemistry and flow cytometry. In contrast, undifferentiated dental pulp cells (OD-21) presented low or no expression of these two receptors. MDPC-23 cells showed CD14 and TLR4 up-regulation upon exposure to LPS, as determined by real time PCR. Dominant negative murine TLR4 (DN-mTLR4) transfected MDPC-23 cells did not show upregulated VEGF expression in response to LPS stimulation. These results demonstrate that odontoblast-like cells express CD14 and TLR4, and that LPS-induced VEGF expression is mediated, at least in part, by TLR4 signaling.
Apical Leakage of Root-End Placed SuperEBA, MTA, and Geristore Restorations in Human Teeth Previously Stored in 10% Formalin
Michael R. Pichardo, DDS, Scott W. George, DDS, Brian E. Bergeron, DMD, Billie G. Jeansonne, DDS, PhD, Rick Rutledge, DDS
The purpose of this study was to determine if storage of extracted teeth in 10% formalin affects microleakage of MTA, Geristore, or SuperEBA root-end fillings. There were 130 freshly extracted single-rooted teeth collected, immediately placed in phosphate buffered saline (PBS) and stored for less than 24 hours. Teeth were divided and either placed in 10% formalin for a 4-weeks immersion or immediately prepared. Preparation for all teeth consisted of canal instrumentation, obturation, apical resection, retrograde preparation, and placement of a root-end filling material. After 72 hours, the apical portions were immersed in India ink under vacuum pressure for 30 minutes, and then stored in ink for 1 week. Negative controls and positive controls performed as expected. In general, there was significantly less dye leakage of root-end restorations in teeth stored in 10% formalin when compared to the freshly extracted teeth (p < 0.0001). No difference in dye leakage was observed between Geristore restorations placed in teeth stored in formalin as compared to fresh teeth (p = 0.892). Less dye leakage was noted in teeth restored with Geristore as compared to MTA and SuperEBA, regardless of storage medium (p < 0.0001). No difference was observed between MTA and SuperEBA root-end restorations (p = 0.157). The results of this study provide evidence that storage of teeth in 10% formalin over a 4-week period may significantly influence dye leakage as compared to leakage in freshly extracted teeth.
Comparison of the Shaping Ability of RaCe and FlexMaster Rotary Nickel-Titanium Systems in Simulated Canals
Sarah J. Merrett, BDS, MFDS, Susan T. Bryant, BDS, Paul M.H. Dummer, BDS, MScD, PhD, DDSc
The aim of this study was to compare the shaping ability of RaCe and FlexMaster rotary nickel-titanium instruments in simulated canals. A total of 80 canals with four different shapes were prepared with either RaCe or FlexMaster instruments. Pre- and postoperative images of each canal were recorded and combined using image analysis software. The development of canal aberrations and transportation was assessed. There was a significant difference (p < 0.001) between the systems for time of preparation to apical size 30, .06 taper; FlexMaster instruments took on average 1.86 min and RaCe 1.66 min. One RaCe and two FlexMaster instruments fractured. No zips, elbows, or danger zones were created. One perforation and eight outer widenings were created using FlexMaster instruments; RaCe instruments created two outer widenings. No differences were found between the instruments for direction of transportation. RaCe and FlexMaster nickel-titanium instruments prepared canals rapidly with few aberrations.
An In Vitro Comparison of the Intraradicular Dentin Bond Strength of Resilon and Gutta-Percha
Lance J. Skidmore, DDS, David W. Berzins, PhD, James K. Bahcall, DMD, MS
The purpose of this study was to compare the micropush-out bond strength of Resilon to that of gutta-percha. Extracted human anterior teeth were used for evaluation. The crowns were removed and the root canals were instrumented with Gates Glidden drills and 0.06 Profile rotary files. Instrumentation was performed with 5.25% sodium hypochlorite irrigation and a final rinse of 17% EDTA. The teeth were randomly divided into two groups. Gutta-percha group: obturation with gutta-percha and Kerr Pulp Canal Sealer EWT. Resilon group: obturation with Resilon points, Epiphany Primer, and Root Canal Sealant. The teeth were cut perpendicular to their long axis to obtain a series of 1.0 mm thick disks (n = 15 per group). Micropush-out bond strengths to root canal dentin were measured. The results show that the mean bond strength to root canal dentin was significantly higher (p < 0.05) in the Resilon/Epiphany group as compared to the gutta-percha/Kerr Pulp Canal Sealer EWT group.
Effects of Sodium Hypochlorite and Chlorhexidine Solutions on Resilon (Synthetic Polymer Based Root Canal Filling Material) Cones: An Atomic Force Microscopy Study
Sehnaz İsci, DDS, Oguz Yoldas, DDS, PhD, Aysin Dumani, DDS
The aim of the present study is to evaluate the effects of 2% chlorhexidine and 5.25% sodium hypochlorite on the surface properties of Resilon cones with the atomic force microscopy. The Resilon cones were immersed in disinfecting agents (5.25% sodium hypochlorite and 2% chlorhexidine) at 1 and 5 min time intervals. Atomic force microscopy was used to evaluate topographical deviations of Resilon cones. Root mean square (RMS) parameters for topographic amplitudes were calculated. The cones exhibited statistically significant low RMS values at 5-min immersion in sodium hypochlorite and chlorhexidine groups compared to the all other groups (p < 0.05). One-minute immersion did not show any significant deterioration on the Resilon surface (p > 0.05). In conclusion, sodium hypochlorite and chlorhexidine solutions used for disinfection significantly decreased (p < 0.05) the RMS values of Resilon cones at 5-min applications.
Reduction in Antimicrobial Substantivity of MTAD After Initial Sodium Hypochlorite Irrigation
Franklin R. Tay, Noriko Hiraishi, George S. Schuster, David H. Pashley, Robert J. Loushine, Hani F. Ounsi, Simone Grandini, Joyce Y.Y. Yau, Annalisa Mazzoni, Adam Donnelly, Nigel M. King
Potential intrinsic tetracycline staining of intraradicular dentin has been observed when BioPure MTAD was employed as the final irrigant after initial rinsing with NaOCl. This study examined the effect of NaOCl-MTAD interaction on the antimicrobial substantivity of MTAD in dentin. Dentin cores previously irrigated with either MTAD, or in conjunction with 1.3% NaOCl as an initial irrigant were placed on blood agar plates inoculated with Escherichia faecalis at 105 cfu/ml. Dentin cores irrigated with 1.3% NaOCl only, and autoclaved dentin disks were used as the respective positive and negative controls. After anaerobic incubation, the mean diameter of bacterial inhibition zones formed around the MTAD group was significantly larger than the NaOCl/MTAD group, which, in turn, was not significantly different from the NaOCl positive control. Oxidation of MTAD by NaOCl resulted in the partial loss of antimicrobial substantivity in a manner similar to the peroxidation of tetracycline by reactive oxygen species.
An In Vitro Evaluation of the Apical Sealing Ability of a New Resin-Based Root Canal Obturation System
Emel Olga Onay, DDS, PhD, Mete Ungor, DDS, PhD, Hasan Orucoglu, DDS, PhD
The purpose of this study was to assess the apical sealing ability of the new resin-based Epiphany-Resilon root canal filling system, and to compare this with the sealing abilities of different pairings of AH plus, gutta-percha, Epiphany, and Resilon. Seventy extracted human single-rooted teeth were used. All teeth were instrumented using a set of ProTaper rotary instruments. The canal spaces were filled with different combinations of core and sealer using lateral condensation, as follows: group 1, AH Plus + gutta-percha; group 2, AH Plus + Resilon; group 3, Epiphany + Resilon; group 4, Epiphany + gutta-percha. Apical leakage quantity was measured with the computerized fluid filtration meter. Statistical analysis indicated that Epiphany gutta-percha combination had the least amount of microleakage than all the other groups; AH Plus gutta-percha combination proved to have second least amount of microleakage among the groups. AH Plus-Resilon combination demonstrated the greatest amount of microleakage. There were a significant difference between Epiphany gutta-percha and AH Plus-Resilon combinations (p < 0.05). It was found that there were no significant differences between Epiphany-Resilon combination and all the other groups (p > 0.05).
Photodynamic Therapy for Endodontic Disinfection
Nikolaos S. Soukos, DDS, PhD, Peter Shih-Yao Chen, DMD, MS, Jason T. Morris, DMD, MS, Karriann Ruggiero, BS, Abraham D. Abernethy, BS, Sovanda Som, BS, MS, Federico Foschi, DDS, Stephanie Doucette, BS, Lili Luschke Bammann, DMD, PhD, Carla Raquel Fontana, DDS, Apostolos G. Doukas, PhD, Philip P. Stashenko, DMD, PhD
The aims of this study were to investigate the effects of photodynamic therapy (PDT) on endodontic pathogens in planktonic phase as well as on Enterococcus faecalis biofilms in experimentally infected root canals of extracted teeth. Strains of microorganisms were sensitized with methylene blue (25 μg/ml) for 5 minutes followed by exposure to red light of 665 nm with an energy fluence of 30 J/cm2. Methylene blue fully eliminated all bacterial species with the exception of E. faecalis (53% killing). The same concentration of methylene blue in combination with red light (222 J/cm2) was able to eliminate 97% of E. faecalis biofilm bacteria in root canals using an optical fiber with multiple cylindrical diffusers that uniformly distributed light at 360 degrees. We conclude that PDT may be developed as an adjunctive procedure to kill residual bacteria in the root canal system after standard endodontic treatment.
Effect of Root Canal Treatments on Quartz Fiber Posts Bonding to Root Dentin
Paolo Baldissara, DDS, Francesca Zicari, DDS, Luiz Felipe Valandro, DDS, MS†, Roberto Scotti, MD, DDS
The aim of this study was to evaluate the effect of irrigants and endodontic sealers on fiber post push-out strength in both fatigue cycling and no-cycling conditions. Fifty single-rooted human teeth received five endodontic treatments. The posts were cemented using a flowable composite and a three-steps adhesive. Five specimens from each group were subjected to 2 × 106 cycles of 37.5 N. There were 200 sections obtained for the push-out test. Fatigue cycled groups treated with an eugenol-containing sealer showed the lowest push-out strength (p < 0.001). No significant differences were found among no-cycled groups (p = 0.665). The post-cement interface was found to be weaker than the cement-dentin one. However, fatigue cycles increased the occurrence of cement-dentin failures (p = 0.001). The eugenol-containing sealer reduced the bonding of fiber posts when mechanically cycled, thus the use of a resin-based sealer is advisable.
Initial In Vitro Biological Response to Contemporary Endodontic Sealers
Serge Bouillaguet, DMD, PD, John C. Wataha, DMD, PhD, Franklin R. Tay, DMD, PhD, Martha G. Brackett, DDS, MSD, Petra E. Lockwood
The objective of this study was to evaluate the cytotoxicity of three endodontic sealers (AH Plus/Maillefer-Dentsply, Epiphany/Pentron, GuttaFlow, Coltene-Whaledent). Materials were mixed according to the manufacturer instructions and packed into Teflon molds (10 × 1 mm). For cytotoxicity testing (MTT method), the specimens were placed in contact with cultured cells, then evaluated at two subsequent time points (24 or 72 h). In addition to testing the mixed materials, 5 μl of primer liquid (GuttaFlow and Epiphany) and resin solvents (HEMA, ethanol, sterile water, or acetone) were added directly in culture for 24 and 72 h. The results showed that most materials pose significant cytotoxic risks and that cytotoxicity generally increased with time. At 72 h, GuttaFlow became significantly less toxic than AH Plus, Epiphany sealer, and Resilon. The current results support the need to continue to develop better endodontic sealers that combine the excellent sealing and bonding properties of resins with acceptable biological properties for endodontic applications.
The Effectiveness of Different Acid Irrigating Solutions in Root Canal Cleaning After Hand and Rotary Instrumentation
Mercedes Pérez-Heredia, BDS, Carmen María Ferrer-Luque, DDS, MD, PhD, María Paloma González-Rodríguez, DDS, PhD
The goal of this study was to evaluate the cleaning ability of three acid irrigating solutions after hand and rotary instrumentation. Eighty human teeth were randomly divided in eight groups. Four groups were prepared with hand instrumentation and other four with ProTaper. The irrigating solutions were 15% citric acid plus 2.5% NaOCl; 15% EDTA plus 2.5% NaOCl; 5% orthophosphoric acid plus 2.5% NaOCl; and 2.5% NaOCl alone as control. Canal walls were observed with scanning electron microscopy, and photomicrographs were taken in apical, middle, and coronal thirds. A scoring system for debris and smear layer was used. Acid solutions with 2.5% NaOCl were effective in the elimination of smear layer or debris, and no significant differences were showed in smear layer removal between techniques. However, 2.5% NaOCl did not remove smear layer or debris, and no significant differences in debris were observed between manual and rotary techniques.
Polymicrobial Leakage of Four Root Canal Sealers at Two Different Thicknesses
Gustavo De-Deus, DDS, MS, Tauby Coutinho-Filho, DDS, PhD, Claudia Reis, DDS, MS, Cristiana Murad, DDS, MS, Sidnei Paciornik, Physicist, PhD
The present study investigated the sealing ability of four root canal sealers at two different thicknesses. There were 82 maxillary incisors roots prepared with Gates Glidden drills up to size 6 and divided into four groups: Pulp Canal Sealer, EndoREZ, Sealapex, and AH Plus. Each group was divided in two subgroups and gutta-percha cylinders 1.5 or 1 mm wide were used, respectively. The roots were mounted in a bacterial leakage model and the system was checked daily during the following 12 wk. Data were analyzed by Log-Rank test and Student t-test. In the thin layer samples, the sealers demonstrated similar results while, in the thick layer samples, AH Plus revealed the best performance. Generally, greater sealer thickness influenced negatively the sealing ability of the root canal filling, except in AH Plus samples.
Maxillary Central Incisor With Two Root Canals: A Case Report
Emílio Carlos Sponchiado Jr, DDS, MD, Hanan Awwad Abdel Qader Ismail, Ac, Márcia Raquel Lima Braga, DDS, Fabrício Kitazono de Carvalho, DDS, MD, Cláudia Andréa Correa Garcia Simões, DDS, MD
The success of endodontic therapy requires a knowledge of the internal and external dental anatomy and its variations in presentation. The internal anatomy of the maxillary central incisor is well known and usually presents with one root and one radicular canal system. This case report describes an endodontic treatment of a maxillary central incisor with two roots and two canal systems, demonstrated by radiography and computerized tomography examinations.
Cemental Tear: A Case Report of a Rare Root Fracture
Michael J. Tulkki, DDS, Michael K. Baisden, DDS, Scott B. McClanahan, DDS, MS
A 79-yr-old female presented to the clinic for endodontic evaluation of an unresolved periodontal defect. The patient’s dental history included extraction of tooth #30 with subsequent placement of two dental implants. The patient presented with a localized periodontal defect on the distal of tooth #29. Radiographic evaluation revealed a thin radiopacity and associated radiolucency along the entire lateral aspect of tooth #29. Periodontal surgery and biopsy resulted in a diagnosis of cemental tear. Cemental tears have been rarely reported in the endodontic literature. Case reports of cemental tears have been associated with age, trauma, and traumatic occlusion. With the increasing age of the dental population and longer retention of teeth, clinicians should be aware of this rare entity.